Double sequential defibrillation therapy for out-of-hospital cardiac arrests: The London experience

Refractory ventricular fibrillation remains a problem for out of hospital cardiac arrests, despite advances in treatment. While ventricular fibrillation is often treatable, there is a subset of cases that do not respond to repeated attempts at traditional defibrillation. Recent studies have suggested that double sequence defibrillation may be useful as in these patients. Double sequence defibrillation is a defibrillation technique wherein 2 shocks are delivered within quick succession. This study aimed to utilize a local EMS protocol in conjunction with a highly trained EMS unit to determine if double-sequence defibrillation results in improved outcomes in those patients with refractory ventricular fibrillation (RVF). RVF is generally considered to exist after 3 shock attempts.

This was a retrospective, observational study that observed 18 months of data from 24 paramedics specially trained in the use of double sequence defibrillation (DSD). All patients who received DSD following standard defibrillation attempts (defined as 6 shocks in this case) were included in the study. Likewise, to compare against the DSD patients, those patients with RVF treated with standard defibrillation were identified. Outcomes measured included pre-hospital ROSC, ROSC sustained to hospital, and survival to hospital discharge.

45 total patients were treated by these specialized paramedics over the 18 month period. Over the same time period, 175 patients were treated with standard defibrillation. In the DSD group, ROSC was obtained in 37 8% of patients, with 58.8% of those sustaining ROSC to the hospital. Only 3 patients (7%) survived to hospital discharge. Very similar results were noted in the non-DSD group. 34.9% achieved ROSC, 55.7% of those sustained ROSC to the hospital, and 6.6% survived to hospital discharge.

Our group discussed the multiple limitations of this study. First and foremost, the study looked at a very small sample size of only 45 total patients. Additionally, a lack of randomization and blinding are significant limitations. Demographically, the DSD group was noted to have a significantly higher proportion of witnessed arrests as compared to the non-DSD group. There was additionally no obvious ACLS standardization, and there is concern that these specially trained paramedics may be performing differently than standard paramedics in the field. They had also previously stated that the generally accepted definition of RVF occurred after 3 shocks, but placed in the protocol not to perform DSD until after 6 standard defibrillation attempts. In summary, there were many limitations to this study, but it certainly warrants further research.


Impact of total occlusion of culprit artery in acute non-ST elevation myocardial infarction: a systematic review and meta-analysis

Total occlusion of culprit artery usually results in a ST-elevation myocardial infarction. However, there is a subset of patients with elevated troponin without ST-segment elevation who are found on PCI to have total occlusion. The purpose of this study was to identify if there is a significant different in outcomes between NSTEMIs with and without total occlusion of the culprit artery.

This was a systematic review and meta-analysis of 7 studies that compared clinical outcomes of NSTEMI patients with partial, total, or non-occluded culprit arteries. Identification of studies was performed by the two lead authors, and disagreements on study inclusion was resolved with discussion between them. Quality of the included studies were measured by the Newcastle-Ottawas Scale, which assesses the methodological quality of cohort studies. Outcomes measured included all-cause mortality and major cardiac adverse events (MACE). Secondary parameters measured included Killip class, LVEF, and time to angiography.

A total of 40, of 700 patients were included in the analysis, of which 25.5% had total occlusion of the culprit artery. The frequency of culprit artery in the total occlusion group was noted to be RCA (40%) > LCX (32%) > LAD (28%), whereas the non-total occlusion group had a frequency of LAD (44%) > LCX (28%) > RCA (27%). In all of these cases, there was a lack of classic ST-elevation on EKG. Short term all-cause mortality was noted to be increased in the total occlusion group, with RR of 1.67, and medium to long term all-cause mortality was noted to be increased as well with a RR of 1.42. Likewise, patents with total occlusion had increased risk of MACE, with a relative risk of 1.41.

Although the studies included were all noted to be observational studies, and there may have been differences in EKG interpretation between the included studies, our group commended this meta-analysis for its good study inclusion. We discussed that while the line between STEMI and NSTEMI can be ambiguous, it's important to recognize that some of our patients with NSTEMIs can have what is essentially a "silent" STEMI, and to take extra care when interpreting EKGs and determining proper disposition. Additionally, we discussed the importance of always checking old EKGs, as there are often EKG changes besides ST-segment changes that may suggest a more serious etiology.


Refractory ventricular fibrillation treated with esmolol

Refractory ventricular fibrillation (RVF) remains a problem for out of hospital cardiac arrests, despite advances in treatment. While ventricular fibrillation is often treatable, there is a subset of cases that do not respond to repeated attempts at traditional defibrillation. Various animal studies, including case reports and case series, have reported success with the use of beta-blockers in RVF. However, there is limited evidence for the efficacy of adjunctive beta-blocker use versus traditional therapy. The purpose of this study is to evaluate the use of esmolol as a treatment for RVF in out-of-hospital cardiac arrests.

This was a single center retrospective pre-post study that followed patients from 2012 to 2013 who did not receive esmolol as part of their treatment for RVF, and compared outcomes to patients followed from 2014 to 2015 who did receive esmolol for the RVF treatment. Verbal consent for esmolol use was given by patients' relatives located at the bedside during resuscitation, with written consent obtained following the resuscitation. Outcomes measured included sustained ROSC without recurrence of RVF primarily, with secondary outcomes measured being survival to ICU admission, survival to discharge, and survival with favorable neurological outcomes.

16 patients were identified from the study group (post-phase) as having RVF, and 25 patients from the control group (pre-phase). Sustained ROSC was noted to be more common in the esmolol group, noted to be 56% versus 16% for the standard treatment group. The esmolol group additionally had better rate of survival to ICU admission (again 56% to 16%), but the difference in survival and survival with good neurological outcome was noted to be statistically insignificant.

Our group primarily discussed the chief limitation of this study: size. The study and control populations were very small, and large variations in data can exist when sample sizes are not sufficiently large. Additionally the nature of a pre-post study versus a randomized controlled trial allows significant bias to emerge. The study did note a statistically significant difference in rate of achieving ROSC between esmolol and non-esmolol groups. We discussed that is is possible for this study to change practice, in that we could use it as a last option, but that we would likely need more data, possibly in a multi-center randomized clinical trial, to make this a regular part of practice.


Submitted by Dr. Will Morris, PGY-1

Randomized Trial of Icatibant for Angiotensin Converting Enzyme Inhibitor-Induced Upper Airway Angioedema

There is no current, effective pharmacologic treatment for upper airway angioedema that occurs as a results of ACE-Inhibitor use. Although it is a rare adverse effect, it is life-threatening, which prompted this study. Icatibant has been proven to be efficacious in the management of hereditary angioedema, so the investigators wanted to see if it can have a role in the management of ACE-I induced angioedema.

This was a randomized double-blind, placebo controlled, trial which collected data from 31 centers in 4 countries. The study investigated the efficacy of icatibant in decreasing the time to discharge for patients who presented within 12 hours of symptom onset of at least moderately severe ACE-I induced angioedema. The primary measure was time to meeting discharge criteria, determined by a blinded physicians' hourly assessment, after administration of the study drug. 121 subjects were randomized, with 61 receiving Icatibant and 60 receiving placebo. Ultimately, there was no significant observed difference in time to meeting discharge criteria with a median time of 4.0 hours in each group. There was no significant difference in the time to onset of symptom relief with either with a median of 2.0 hours for Icatibant and 1.6 hours for placebo.

The study had strict exclusion criteria to reduce the likelihood of enrolling patients that may have developed angioedema as a result of another etiology. One confounding factor to the study was the shorter time to onset of symptom relief for the placebo group, and there could be many explanations for this finding. Even though the study was careful to exclude patients with upper airway angioedema from another etiology, it is still possible that there were patients included in the study with multifactorial agnioedema that may have at least partially responded to the standard, steroids, antihistamines, and epinephrine treatment. Also, there is an inherent delay between the time of symptom onset and administration of the study drug for many reasons, which may have had an effect on the results of this study.


An Observational Study to Determine Whether Routinely Sending Patients Home with a 24-Hour Supply of Topical Tetracaine from the Emergency Department for Simple Corneal Abrasion Pain is Potentially Safe

The management of pain and irritation from simple corneal abrasion is a common problem in the ED. Traditionally, patients would receive pain relief from tetracaine for the purpose of eye examination in the ED, but they would not be given tetracaine for relief at home due to the potential adverse effects associated with prolonged use.

This was a retrospective cohort study in which physician were able to dispense a 24-hour supply of tetracaine hydrochloride 1% eye drops for pain relief in patients with corneal abrasions. The goal of the study was to determine if the number of ED rechecks, persistent fluorescein uptake, ophthalmology referrals, or complications would be affected by the prescription of topical tetracaine for simple corneal abrasions. Tetracaine was only supposed to be supplied to patients with a simple corneal abrasion, defined as fluorescent uptake on cornea, subjectively small, non-penetrating, non-lacerating, and occurring within the past 2 days due to trauma, not chemical, contact lens use, thermal burns, contaminated wounds, or infection. The classification of SCA versus non-SCA was determined by the data collector according to the aforementioned rules. Tetracaine was dispensed at the initial visit for 303 presenting patients with SCA. It was inappropriately dispensed for 141 cases of non-SCA. No serious complications or uncommon adverse events were attributed to tetracaine for either the patients with SCA, nor those with non-SCA. The RR of ED recheck and fluorescein staining was increased overall among patients receiving tetracaine at 1.67, but the RR for those with only SCA receiving tetracaine was 1.16. Ultimately, no evidence was found that would indicate 24-hour use of tetracaine in the case of SCA was unsafe. There was some observed increased risk on the cases of inappropriate tetracaine for non-SCA.

There was some subjectivity to the term SCA and the study relied on the initial charting physician. The researchers that initially collected data were not blinded to the study hypothesis. However, there was a second researcher who scrutinized the data collected by the first researcher. Also, data could only be collected for patients who returned for rechecks. It is possible that there were non-reported adverse effects.



Effects of Oral Dexamethasone without Immediate Antibiotics vs Placebo on Acute Sore Throats in Adults

Acute sore throat is a common chief complaint in the primary care setting, and it represents a major source of inappropriate antibiotic usage. The use of corticosteroids for symptoms relief should be considered in the absence of contraindications when antibiotics are inappropriate.

This was a double-blind, placebo-controlled randomized trial looking to assess the clinical efficacy of oral corticosteroids for acute sore throat in the absence of antibiotics. 576 adults, at least age 18 or older, with acute sore throat were recruited on the day of presentation to primary care when immediate antibiotic therapy was not indicated. The primary measure of the study was the proportion of participants who experienced complete symptom resolution at 24 hours. Secondarily, they measured the proportion of patients with complete symptoms resolution at 48 hours, duration of moderately bad symptoms, visual analog symptom scales, health care attendance, days missed from work or education, consumption of delayed antibiotics, or other medication and adverse events.

Ultimately, the study found that at 24 hours, the patients receiving the single dose of oral dexamethasone were not more likely to have symptoms resolution as compared to the placebo group. 22.6% of the patients receiving dexamethasone and 17.7% of the placebo group reported complete resolution. At 48 hours, however the participants receiving dexamethasone were considered to be more likely to have complete symptoms resolution. 35.4% of the patients receiving dexamethasone and 27.1% of the placebo group reported complete symptoms resolution.

It is possible that the small measured efficacy is due to corticosteroids being more beneficial for severe sore throat. This study aimed to evaluate the efficacy of dexamethasone in the absence of antibiotics, so patients with severe sore throat that received antibiotics were excluded from the trial. Thus, the efficacy of dexamethasone mono therapy wasn't evaluated in a severely ill population, which may have received more benefit.


Submitted by Dr. Daniel Laursen, PGY-1

Implementation of a Regional Telephone Cardiopulmonary Resuscitation Program and Outcomes After Out-of-Hospital Cardiac Arrest

Cardiac arrests in an out-of-hospital setting is a major health problem, which requires a "chain of survival" to allow for successful resuscitation. The initial links in this chain are the prompt recognition of cardiac arrest and the activation of the emergency response system, early CPR and defibrillation. Bystander performed CPR (BCPR) has been shown to double or even triple the survival of out-of-hospital arrest in prior studies.

This was a prospective observational study to investigate the effect of a Telephone Cardiopulmonary Resuscitation (TCPR) Program bundle of care on T-CPR process measures and outcomes, before and after its implementation. This study observed adult patients with out-of-hospital cardiac arrest not receiving bystander CPR before 911 was called between October 1, 2010 and September 30, 2013. Primary outcome was survival to hospital discharge and functional outcome at hospital discharge. The T-CPR program feedback in two regional dispatch centers serving metropolitan Phoenix, Arizona. The need to perform CPR was indicated when it was determined that the patient was not conscious and was not breathing normally, i.e. absence of breathing, agonal breathing, or a rapid or a slow respiratory rate. There was 2,334 out-of-hospital cardiac arrests, with 97% due to presumed cardiac origin, during this time frame in the study group with 64% males, and median age of 63 years old (range from 9-101 years old).

The median time to first chest compression was decreased from 256 seconds to 212 seconds. Survival, for all rhythms, was higher after implementation of TCPR program, 9% vs 12% with an adjusted odds ratio of 1.47 p=0.02. Patients that were noted to have a shockable rhythm, had significantly improved survival after TCPR, 24.7% vs 35.0% with an adjusted odds ratio of 1.70 p=0.02. Patients with a favorable outcome were also significantly higher after TCPR program implementation, 5.6% vs 8.3% with an adjusted odds ratio of 1.68 p=0.01. Additionally, the researchers found that BCPR, CPR performed by a bystander lay rescuer, increased from 61.8% to 66.8%, whether TCPR instructions were given or not.


Bystander Efforts and 1-Year Outcomes in Out-of-Hospital Cardiac Arrest

Due to improvements in bystander interventions during cardiac arrest and post-resuscitation care, survival after out-of-hospital cardiac arrest has improved, however, there has been little research in long term functional outcomes, including how bystander interventions, including CPR and defibrillation, have impact on these outcomes.

This was an observational study that looked to investigate whether the improvement in bystander interventions and post-resuscitation care affected long term functional outcomes, including how bystander interventions influence these outcomes. Nationwide data on out-of-hospital cardiac arrests in Denmark were linked to functional outcome data and reported the one-year risks of patients, adults age 18 years and older, who survived to day 30 after out-of-hospital cardiac arrest having anoxic brain damage, nursing home admission, or death from any cause. This study analyzed outcomes according to whether patients received bystander CPR and bystander defibrillation, and the temporal changes in bystander interventions and outcomes. During the period from 2001 through2 012, 42,089 patients had an out-of-hospital cardiac arrest, 2855 patients were eligible for inclusion in their study and survived to day 30. A total of 10.5% of these patients had brain damage or were admitted to a nursing home, Additionally, 9.7% died during the one-year follow up period.

It was noted that for the 2084 patients that had a cardiac arrest not witnessed by emergency medical services (EMS) personnel, the rate of bystander performed CPR increased from 66.7% to 80.6%, bystander defibrillation rate increased from 2.1% to 16.8% during this timeframe as well. Additionally, the rate of brain damage or nursing home admission decreased from 10.0% to 7.6% and all cause mortality decreased from 18.0% to 7.9%.

These researches concluded that since this study demonstrated associations between early bystander cardiac resuscitation efforts and a lower one-year risk of anoxic brain injury, or nursing home admission further supports the need to apply and/or improve approaches that help bystanders to start CPR and aid in public access to AEDs.


Delayed Diagnoses in Children with Constipation: Multicenter Retrospective Cohort Study - NARDI

There are greater than 250,000 visits to EDs for children that are diagnosed with constipation. Prior research has shown that major misdiagnoses are uncommon between 0.4% and 0.8% with appendicitis the leading missed diagnosis.

This was a retrospective cohort study of children ages 18 years and younger that were diagnosed with constipation, impaction of intestine, or encopresis, between 2004 and 2015 at one of 23 different emergency departments in the US. The primary outcome was a 3-day ED revisit with a clinically significant alternative diagnosis. The primary exposure was abdominal radiograph performance, since abdominal radiographs contribute to increased healthcare costs, radiation exposure, and potentially missed diagnoses.

There were 282,225 children included in this study. Of these patients, 185,439 (65.7%) had an index ED visit where abdominal radiographs were performed. They found that 3.7% of children had a three-day revisit, with 0.28% of all children found to have a clinically significant alternative diagnosis. The most common 3-day visit with clinically significant alternative diagnosis was appendicitis, 267 patient or 34.1%. Of the children that had an abdominal radiograph performed, they were found to be more likely to have a 3-day revisit with a clinically significant alternative diagnosis, 0.33% vs 0.17% with an adjusted odds ratio of 1.39. Additionally, they found that the performance of abdominal radiographs was an independent risk for a 3-day revisit with a clinically significant alternative diagnosis, along with narcotic and non-narcotic analgesics, antiemetics and the presence of complex chronic conditions.

They concluded that their data suggested that among children with diagnosed constipation, clinical features may help identify children at increased risk of having a clinically important alternative diagnosis and mindfulness of these attributes may help clinicians identify atypical patient presentations to reduce diagnostic error. Additionally, they noted a prior report, which stated that additional testing may reflect diagnostic uncertainty or alternatively it may be that the more tests and/or therapies, the more likely a family is to seek additional ED care in the future.

Submitted by Dr. Lee Raube, PGY-1

Predicting Fluid Responsiveness by Passive Leg Raising: a Systematic Review and Meta-Analysis of 23 Clinical Trials

Critically ill patients often receive fluid therapy in the treatment of shock. However, studies have shown that unnecessary fluid administration can actually increase morbidity and mortality. Therefore, determining an accurate way to assess "fluid responsiveness" may improve patient outcomes in the future. Passive leg raising creates a reversible increase in venous return, mimicking fluid administration.

This is a systematic meta-analysis determining the predictive value of passive leg raising on fluid responsiveness. Twenty-three articles were included in this study with a total of 1013 patients. In all studies chosen, a fluid challenge was given a gold standard to delineate fluid responders and non-responders, passive leg raise was performed, and adequate data was available for statistical analysis.

The mean patient age was 59 +/- 9 years, with an average cardiac output of 5.5 +/- 1.2 L/min. Patients were clinically characterized as suffering from poor tissue perfusion. Measurements were made by esophageal Doppler, transthoracic echocardiography, calibrated pulse contour analysis, and tioreactance. All of these methods measure a flow as outcome, representing the cardiac output.

The global predictive value of passive leg raising had a pooled sensitivity of 86%, specificity of 92%, and area under the receiver operating characteristic curve (AUROC) of 0.95. The result was unchanged by variables such as ventilation mode, type of fluid used, passive leg raise starting position, or technique measuring the change in flow induced by the passive leg raise. Therefore, investigators concluded that passive leg raise is a reliable predictor of fluid responsiveness.

Our group discussed several limitations of this study. In the study, investigators do not provide an exact definition of fluid responsiveness. In addition, different measurement techniques used in the analysis had different cutoff values. Finally, this study did not cover pediatrics, which if included would further strengthen the result. In all, our group concluded that passive leg raising does appear to be a tool that can be used to predict fluid responsiveness in these critically ill patients.


Prevalence of Pulmonary Embolism Among Patients Hospitalized for Syncope

The differential diagnosis of syncope is separated into several distinct categories; it can be neurally mediated, caused by orthostasis, or can have a cardiovascular origin. Pulmonary embolism (PE) is included in this differential diagnosis, however the prevalence of PE as a cause of syncope has not been well studied. Because of this, patients admitted after an episode of syncope are rarely worked up for PE as a cause. The investigators in this study set out to assess the prevalence of PE in patients hospitalized for a first episode of syncope.

This was a cross-sectional study that included patients older than 18 years of age who were hospitalized for a first episode of syncope. Syncope was defined as a transient loss of consciousness with rapid onset, short duration, and spontaneous resolution, with obvious causes ruled out. Patients were cared for at 1 of 11 different hospitals located in Italy All patients underwent EKG, chest x-ray, blood gas testing, and d-dimer assay. In patients with high pretest clinical probability and positive d-dimer, CT pulmonary angiography or ventilation-perfusion lung scanning (VQ scan) was performed. Criterion for presence of PE was an intraluminal filling defect of at least 75% of a segment with corresponding normal ventilation.

A total of 560 patients were included in the study. Most patients were elderly, with >75% 70 years of age or older. 17.3% of the patients meeting criteria were found to have PE confirmed on CT or VQ scan. Prevalence was highest among patients who had syncope of undetermined origin, however 13% of patients with potential alternative explanations for syncope had PE.

Our group discussed one key limitation of this study. The greatest limitation is that the study only included patients that were admitted for syncope, therefore it did not include patients seen in the ambulatory setting or those discharged from the emergency department. We agreed that PE should be more routinely included in our workup of undifferentiated syncope.


Effect of Hydrocortisone on Development of Shock Among Patients with Severe Sepsis

The use of hydrocortisone treatment in patients with severe sepsis and septic shock has been debated for decades. Previous studies have not been consistent. One study showed improved survival and reversal of septic shock. Another showed accelerated reversal of septic shock, but failed to demonstrate significant reduction in mortality. However, hydrocortisone has been shown to significantly improve survival and progression to shock in patients with community acquired pneumonia. It was thus hypothesized that early hydrocortisone administration might prevent shock development in patients presenting with severe sepsis.

This was a multi center, placebo-controlled, double blind study conducted at 34 sites in Germany. Patients were in an intermediate or ICU care and had to meet several inclusion criteria. These were that patients provided informed consent, had evidence of infection, had evidence of a systemic response to infection, and had evidence of organ dysfunction present for not longer than 48 hours. Main exclusion criteria was septic shock, which was defined as mean arterial pressure (MAP) < 65 mmHg, or use of vasopressors to maintain MAP above 65 mmHg. The primary endpoint was occurrence of septic shock within 14 days.

A total of 9953 patients were screened for eligibility, and 380 patients were chosen and randomized to receive hydrocortisone or placebo. Characteristics between the two groups were comparable. No significant difference was found in the proportion of septic shock after 14 days between patients who received hydrocortisone or placebo. In addition, no significant difference in secondary endpoints such as 28 day, 90 day, 180 day, ICU or hospital all-cause mortality, LOS in the ICU or hospital, ventilation or renal replacement free days, or Sequential Organ Failure Assessment score. In addition, there were more episodes of hyperglycemia in the hydrocortisone group, and two patients developed severe hypertension requiring antihypertensive therapy.

Our group discussed how well the study was conducted. It was randomized, double-blinded with similar groups that were treated similarly. In addition, we commended the journal for publishing a negative study, which showed the treatment not to be helpful. The study points out that this contradicts the previous study on effects of hydrocortisone treatment on community acquired pneumonia, which only included 46 patients. This will need to be further studied in the future to determine its application, however this study is strong evidence that steroids should not be given to patients in severe sepsis.


Submitted by Dr. Bradley Stone, PGY-1

Renal colic is a common presentation to the emergency department (ED), affecting approximately 10% of the population worldwide. [1] Providing adequate analgesia to this group can be challenging. Therapeutic staples such as ketorolac followed by morphine are commonly used. However, ketorolac will typically only be dosed once for analgesia in the ED. Morphine and other opioids can be given repeatedly, but they can cause unwanted side effects. Additionally, with 14,000 prescription opioid deaths in 2014 alone, there has been several resources discussing the concept of opioid free EDs. [2-4] Alternatives to opioids for pain control for renal colic would be beneficial, and may reduce the number of opioids prescribed on discharge.

Clinical Question: is intravenous lidocaine useful for the treatment fo pain associated with acute renal colic in the ED?

Journal Article: Effectiveness of Intravenous Lidocaine Versus Intravenous Morphine for Patients with Renal Colic in the ED. [5]

Study Design: Randomized double blind, comparator trial

Population: Patients aged 18-55, without history of renal, cardiac or hepatic disease and were not pregnant. Those with an allergy to lidocaine were also excluded.

Patient selection and interventions: patients presenting with flank pain, pain radiating to the groin, nausea, vomiting, dysuria, and CVA tenderness, along with a hematuria on urinalysis were selected. All patients received metoclopramide 0.15 mg/kg on enrollment into the study. To avoid withholding pain medication to those with the renal colic, patients were randomized to receive lidocaine 1.5 mg/kg (max dose 200 mg), or morphine 0.1 mg/kg (max dose 10 mg) at enrollment. The diagnosis was later confirmed by KUB plain films and ultrasound.

Primary Outcomes: pain score < 3 on Visual Analog Scale (VAS) after 30 minutes

Results: 120 patients were enrolled into each arm. There were no significant differences in regards to age, stone side, hydronephrosis, or history of stones between the two groups. The primary outcome was achieved in 90% of the lidocaine group versus 70% of the morphine group. The mean pain scores after 30 minutes on the VAS were 1.13 and 2.23, respectively. The side effects were minimal overall and similar between the two groups, with the most common being dizziness with the use of lidocaine.

Limitations:

• Small sample size
• Over reliance on clinical impression for diagnosis
• Lack of confirmation with gold standard
• Short term outcome without follow up

Discussion: Overall this is useful article. It provides us with some evidence of using lidocaine for pain in renal colic, and is the best evidence we have available at this point. Lidocaine has also been shown to be beneficial as an adjunct to morphine for pain cotnrol in renal colic. [6]

Clinical bottom line: In young and healthy people with renal colic, lidocaine may be considered as an alternative agent for pain control.

References

1. Ban KMaE, JS. Selected Urologic Problems. In: Marx J, Hockenberger R, Walls R, Biros M, et al, ed. Rosen's Emergency Medicine Concepts and CLinical Practice 8th ed. Philadelphia, PA: Elsevier Saunders, 2014.
2. Weingart SD. Podcast 139. Opioid-Free ED with Sergey Motov. EMCrit, 2016.
3. Prevention CfDCa. Prescription Opioid Overdose Data. Secondary Prescription Opioid Overdose Data. 2016.
4. Hipskind J, Kamboj K. Pain Points: Non-Narcotic Management of Acute and Chronic Pain. Critical Decisions in Emergency Medicine 2016;30(10).
5. Soleimanpour H, Hassanzadeh K, Vaezi H, Golzari SE, Esfanjani RM, Soleimanpour M. Effectiveness of intravenous lidocaine versus intravenous morphine for patients with renal colic in the emergency department. BMC Urol 2012;12:13 doi:10.1186/1471-2490-12-13[published Online First: Epub date]|.
6. Firouzian A, Alipour A. Rashidian DH, et al. Does lidocaine as an adjunvant to morphine improve pain relief in patients presenting to the ED with acute renal colic? A double-blind, randomized controlled trial. Am J Emerg Med 2016;34(3):443-8.

Submitted by Dr. Michael Craddick, PGY-3, Chief Resident

Contrast CT scans in the Emergency Department do not increase risk of adverse renal outcomes
Evidence had previously shown that older CT contrast media, with high osmolality no longer used, was responsible for contrast induced nephropathy (CIN). CIN is defined as creatinine increase by 0.5 mg/dL or 25% above baseline. Despite the change to modern iso-osmolal IV contrast for CT scans, it has remained widely accepted that CT contrast carries the risk of nephropathy and renal failure, when there is actually scarce data on whether this is truly due to the IV contrast itself.

This was a retrospective study using computerized chart review that occurred over 5 years fro 2005-2010 at an urban teaching hospital with census of about 75,000 patients. It compared patients who received CT contrast for CT abdomen/pelvis or chest with a control group who received CT but without contrast. The control group did not receive contrast if the initial creatinine >1.5 mg/dL or if the study did not indicate contrast (ie - renal colic). The patients studied were admitted adults and needed to have at least one additional Cr within the next 96 hours. The contrast media was non-ionic with the same 100 mL dose and either Omnipaque 240 or Isovue 300. Data analysis was performed by a single investigator who was not blinded.

6,954 patients received contrast CT scans vs. 909 patients receiving non-contrasted scans. Age, sex, and incidence of diabetes were similar among the groups. There was no difference in mortality (1.5% vs. control 1.3%) or need for dialysis (0.23% vs. 0%) between the groups. The rate of CIN was also not statistically significant (8.6% vs. 9.6% control with p value 0.32). Surprisingly, there was a higher proportion of control group that had CIN. The article suggests a temporal relationship for CIN among patients who are already sick and being admitted with correlated elevated Cr, but that contrast is not causality. It has been shown in previous studies a 25% increase in Ct in in-patients, even in those who did not receive contrast.

Our group discussed limitations within the study. Although they did well matching age/sex there may have been many other confounding factors such as comorbidities, although there was such a large sample size that this may reduce this. The time period of 96 hours may have also contributed to confounding events that occurred in such a long time frame. Since it was a retrospective study there was no way to standardize when the subsequent Cr would be measured. Finally, ordering CT contrast studies in the ED on patients with renal insufficiency is not likely to be probable, at least just yet. It would require acceptance and mutual agreeance with radiology department before it could be implemented.


Low dose vs. standard dose tPA in acute ischemic stroke
Currently, the standard dose of tPA for acute ischemic strokes is accepted as 0.9 mg/kg. It has since been debated whether a lower dose of tPA would be safer with a lower incidence of intracerebral hemorrhage (ICH). A Japanese study cited in this article showed that using tPA at a dose of 0.6 mg/kg showed similar outcomes but with less ICH. Subsequent studies have had inconsistent results. The Enhanced Control of Hypertension and Thrombolysis Stroke Study (ENCHANTED) set out to compare the low dose to the conventional dose and also assess the effects of early intensive lowering of blood pressure.

The study was an international (13 countries), multi-center (!11 medical centers) prospective study. Patients with suspected ischemic stroke meeting guideline-recommended criteria within the time window of 4.5 hours from symptom onset were randomly assigned to 2 groups. The control group received the standard dose of 0.9 mg/kg (10% bolus, then 90% infusion over 60 minutes) tPA and the other group received low dose of 0.6 mg/kg (15% bolus, then 85% infusion over 60 minutes). Patient with elevated BP were further randomly assigned to the early and intensive lowering of BP vs conventional blood pressure management for an additional future study. 3,310 underwent the study, 1.654 assigned to low dose tPA and 1.643 assigned to the standard dose. Patient characteristics were similar over a wide range of variables including age, sex, comorbidities, NIHSS score and neurologic findings. However, the majority of the patients were of Asian descent (2/3).

Follow up data was obtained at 24 hours, 72 hours, 7 days or discharge (whichever was sooner). They were also evaluated in person or via telephone at 28 and 90 days. Brain imaging was obtained at entry, 24 hours and subsequently if clinically indicated. The primary outcome was combined end point of death and disability at 90 days. The modified Rankin score (mRS) was used to define the outcome: 0-1 meaning good outcome, 2-5 with increasing disability, and death with 6. The secondary outcome was to assess ICH, symptomatic ICH is indicated by Safe-Monitoring Study (SITS-MOST): large focal or remote parenchymal pattern of > 30% of infarcted area, mass effect or extension outside the infarct, and neurologic deterioration with increase in at least 4 points in NIHSS score, or death at 36 hours.

For the primary outcome, mRS 2-6 occurred in 53.2% of low dose tPA group and 51.1% with the standard dose. The determined odds ration was 1.09 with CI 0.95-1.25, crossing the upper limit therefore being non-inferior (negative study). Symptomatic ICH was seen in 1% of low dose and 2% of the standard dose. Although not statistically significat, there were less deaths in the low dose tPA group.

One point raised was that the rate of symptomatic ICH wasmuch less than cited in other studies (2% vs. 8%). Having a better risk gives us a number to define when discussing informed consent for treatment. The criteria for symptomatic ICH were raised in discussion. NIHSS score deterioration of 4 points was thought of as very extreme and it was questioned if there would have been more of a difference if there was more subtle neurologic deterioration. The study was a non-inferiority trial, so it was emphasized that although there may be less harm in low dose tPA the results were focused only on showing non-inferiority and not showing benefit. It does bring up a need for the search for the optimal dose tPA, and there may be certain groups that may benefit from lower or modified dose.


Immediate total-body CT scanning vs conventional imaging and selective CT scanning in patients with severe trauma (REACT-2): a randomized controlled study
Published studies have suggested survival benefit for patients with trauma who have total body CT scans during initial trauma assessment over the standard accepted ATLS guidelines using adjunctive radiographs, ultrasound, and selective CT scans. In a systematic review assessment by the authors, results showed that in 1 out of the 4 studies assessed there was an increase in probability of survival in patient with total-body CT.

This study was an international (Netherlands and Switzerland), multicenter (4 level I trauma centers), randomized controlled trial that occurred from 2011-2014. It compared immediate total body CT scanning with the standard work up in patients with severe trauma.
Eligibility included:

• RR > 30
  
• SBP < 100
• > 500 mL blood loss
• GCS < 13
• Abnormal pupils
• Multiple rib fractures/flail chest
• Severe abdominal injury
• Pelvic fracture
• Unstable vertebral fracture/spinal cord injury
• Fracture > 2 long bones
• Fall > 10 feet
• Severe injury/death to passenger
• Ejection from vehicle
• Trapped by chest/abdomen in vehicle

Trained trauma leaders assigned patients 1:1 to etiher immediate total-body CT or standard work up. Whole body CT scans consisted of first addressing life-threatening interventions, then non-contrasted head and neck scans, then administering contrast for chest, abdomen and pelvic scans. Primary outcomes were mortality (in hospital). Secondary outcomes include morbidity, length of time to diagnosis, time length in trauma bay, and radiation exposure.

1.403 patients were randomly assigned, 702 in the total-body CT scanning group and 701 in the control group. There was no significant difference between the groups for in-hospital mortality (16% of total-body CT scans and 16% in standard workup group). Mortality was also found to be comparable for subgroups among patients with polytrauma and TBI. Not surprisingly, there was higher radiation exposure to total-body scans (20.9 mSv vs 20.6 in the standard work up group), also higher amount of radiation throughout entire hospital admission (21 vs 20.6). Median time to end of imaging was decreased in the total-body CT scan group by 7 minutes. There were 5 serious adverse events that occurred during scanning - three (1%) in the total-body CT group and 1 in the control (<1%).

The group discussed that the patients in the study were not the sickest group (demographics and baseline characteristics are listed in table1) that we would typically thing of a severe trauma. You only needed one of any of the criteria to be included. There might be some utility in total-body CT scans in certain subgroups, perhaps patients who are sicker. Also, although the time benefit appears to be statistically significant, 7minutes overall really isn't clinically significant, and this does not offset the risks of radiation exposure.


Submitted by Dr. Lindsey Budris, PGY-1

Diagnostic Accuracy of High-Sensitivity Cardiac Troponin-T at Presentation Combined with History and EKG for Ruling Out Major Adverse Cardiac Events
Several studies indicate that a single high-sensitivity cardiac troponin T (hs-cTnT) result below the limit  of detection (<5ng/L) at ED presentation can rule out acute myocardial infarction. However, this does not take into account unstable angina and major adverse cardiac events (MACE). It is thought that this can be done by also taking into account patient history and EKG. The purpose of the study is to evaluate the diagnostic accuracy of hs-cTnT level (<14 ng/L) at ED presentation, combined with the physician's assessment of history and EKG, for ruling out major adverse cardiac events (MACE) within 30 days.

This was a prospective observation study that enrolled ED Chest Pain Patients, collecting patient history and EKG. The primary outcome was a 30-day MACE defined as myocardial infarction, unstable angina, cardiogenic shock, ventricular arrhythmia, AV block, cardiac arrest, or death by cardiac or unknown cause. A questionnaire asked for physician's EKG interpretation and clinical gestalt of the patient's history in terms of risk (high, intermediate, low or very low). hs-cTnT levels were categorized into < 5ng/L or < 14ng/L at presentation. Patients were then managed at the discretion of the physician.

Results
High Risk
hs-cTnT > 14 ng/L or ischemic EKG, or high risk history (n=379)

• No 30 day MACE (n=264)
• 30 day MACE (n=115)

Intermediate Risk
hs-cTnT < 14 ng/L and non-ischemic EKG and non-high risk history (n=759)

• No 30 day MACE (n=749)
• 30 day  MACE (n=10)

Low Risk
hs-cTnT < 5 ng/L and non-ischemic EKG and non-high risk history 9n=332)

• No 30 day MACE (n=331)
• 30 day MACE (n=1)

Sensitivity (99.2%), NPV (99.7%), negative LR (0.02)

Single hs-cTnT result of < 5 ng/L at ED presentation is combination of non-ischemic EKG and non-high risk history essentially ruled out the possibility of having a MACE within the next 30 days. This study had a well-defined sample of patients with appropriate follow up. The clinical gestalt of the physician was biased, but they attempted to make everything as objective as possible. However, this study looked at a very low risk subset of people with troponins. This is not exactly the population that we are concerned about the ED. We need something for people in the group where there is some risk seen with their troponin, EKG or history.


Emergency Department Prescription Opioids as an Initial Exposure Preceding Addiction
Opioid abuse and overdose are an increasingly frequent and common problem. It is thought that opioids have little potential for iatrogenic addiction when used as directed (ie, ED setting). This study evaluates the possibility that initial exposure of opioids from the ED could be related to subsequent opioid misuse.

This was a cross-sectional study that surveyed patients reporting heroin or nonmedical opioid use at an urban, academic ED. They then estimated the proportion of patients whose initial exposure to opioids camefrom a legitimate medical prescription and the proportion of those prescriptions that came from an ED. The secondary measurement looked at the proportion of patients receiving nonopioid substances before initial exposure, the source of the opioids between initial exposure and onset of regular nonmedical use, and time from initial exposure to opioid use disorder.

Of 59 subjects, 35 were legitimately exposed by an initial exposure, and 10 of 35 came from the ED. Most medically exposed patients reported nonopioid substance use or treatment for nonopioid substance use disorders preceding the initial exposure. Although short term opioid administration by EPs is unlikely to cause addiction by itself, ED opioid prescription may contribute to addiction in some patients. Although the respondent population reflected our population in the ED, there were some flaws to the study. In terms of sampling error, the age range of 18-40 may have missed key age demographics, especially in the younger population. In terms of response errors, there was a great potential for recall and responder bias in this study. The way they also identified opiate abusers was also subjective. Overall, this is a poorly designed study on a really interesting topic that is gaining a lot of attention, and forcing us to walk the fine line of not over prescribing, while at the same time not under prescribing.


Amiodarone, Lidocaine or Placeboin Out-of-Hospital Cardiac Arrest
Antiarrhythic drugs are used commonly in out-of-hospital cardiac arrest for shock refractory vfib or pulseless vtach, but without proven survival benefit. Amiodarone and lidocaine are used commonly to promote successful defibrillation of shock refractory ventricular fibrillation or pulseless ventricular tachycardia and prevent recurrence. Although amiodarone has been shown in controlled trials to improve return of spontaneous circulation and to survive to be admitted to the hospital, the survival to hospital discharge is still uncertain.

This was a randomized, double blind trial that compared parenteral amiodarone, lidocaine and saline placebo, along with standard care, in adults who had nontraumatic out-of-hospital cardiac arrest, shock refractory vfib or pulseless vtach after at least one shock, and vascular access. The primary outcome was survival to hospital discharge. The secondary outcome was favorable neurologic function at discharge. The difference in survival rate for amiodarone vs placebo was 3.2 percentage points (not significant); for lidocaine vs placebo was 2.6 percentage points (not significant); and for amiodarone vs lidocaine was 0.7 percentage points (not significatn). The neurologic outcome at discharge was similar in the three groups.

Neither amiodarone nor lidocaine resulted in a significantly higher rate of survival or favorable neurologic outcome than the rate with placebo among patients with out-of-hospital cardiac arrest due to initial shock-refractory vfib or pulseless vtach. There was no difference in primary or secondary outcomes between groups. A downfall of this study is that they did not have a time frame of when all of these drugs were delivered, specifically when looking at patient down-time. They should look at witnessed arrests. Overall though, this was a very well done study, and when looking at where this study took place, these are all very high performing centers (Pittsburgh, Seattle, Milwaukee). It will be interesting to see how this study affects us in the ED when ACLS guidelines are updated in the next couple of years. Currently, electricity and high-quality CPR are really the only two proven effective things in successful resuscitation.


Submitted by Dr. Fritz Liaboe, PGY-1

Isopropyl Alcohol Nasal Inhalation for Nausea in the Emergency Department: A Randomized Controlled Trial
Nausea or vomiting is a common chief complaint in the ED. Multiple randomized trials comparing commonly used antiemetics, such as ondansetron, promethazine and metoclopramide, have failed to show their superiority against a placebo. Identifying an antiemetic medication that outperforms placebo would be beneficial to the ED provider.

This study was a randomized, double-blind, placebo controlled trial that used a convenience sample from an urban tertiary care ED. They compared nasally inhaled isopropyl alcohol with nasally inhaled normal saline solution and measured nausea using an 11 point verbal numeric scale. The primary outcome was reduction in nausea after 10 minutes. Secondary outcomes included patient satisfaction and pain reductions measured at 10 minutes poststart.

37 patients received the nasally inhaled isopropyl alcohol and 43 received nasally inhaled normal saline solution. The median nausea verbal numeric response scale score was 3 for the treatment arm and 6 for the placebo arm. The median satisfaction score was 4 for the treatment arm and 2 for the placebo arm. There was no significant difference between the two arms in the median pain response score.

The study showed alleviation of symptoms for only 10 minutes and while both groups required rescue antiemetics, the treatment arm reported higher satisfaction scores. The group discussed whether this treatment would be beneficial to use in the waiting room prior to the patient being seen by a provider.


Intensive Blood Pressure Lowering in Patients with Acute Cerebral Hemorrhage
Patient with intracerebral hemorrhage commonly have an acute hypertensive response that may be associated with hematoma expansion and increased mortality. The Antihypertensive Treatment of Acute Cerebral Hemorrhage II (ATACH-2) trial was designed to help determine the efficacy of rapidly lowering the SBP level in patients in an earlier time window after onset of symptoms than has been evaluated in earlier trials.

This was randomized, multi center, two-group, open-label trial conducted at 110 sites in the US, Germany and four Asian countries. They used IV nicardipine to lower BP to either 110-139 (intensive treatment) or to 140-179 (standard treatment) within 4.5 hours of symptom onset in patients with spontaneous supratentorial intracerebral hemorrhage. The primary outcome was death or disability after 3 months.

The primary outcome was observed in 38.7% of participants in the intensive treatment group and in 37.7% in the standard treatment group. The rate of adverse events attrached to the treatment were found in 1.6% of patients in the intensive treatment group and 1.2% of those in the standard treatment group. The rate of renal adverse events was significantly higher in the intensive treatment group (9% vs 4%). The trial was discontinued for futility before reaching the target enrollment. Thus, they concluded that intensive reduction in SBP level does not provide an incremental benefit.

The group discussed the limitations of the study included that there is missing data, relatively higher proportion of Asian participants (56.2%) and pre-randomization use of intravenous antihypertensive agents. In the real world clinical setting, neurosurgeons still demand for strict control of BP and they will be overseeing this. Also one cannot compare this to the earlier intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial (INTERACT 2) as patients varied greatly in severity.


Ketamine as Rescue Treatment for Difficult to Sedate Severe Acute Behavioural Disturbance in the Emergency Department
Violent patients with agitated delirium can endanger themselves and ED staff. This study aimed to investigate the effecitveness and safety of ketamine in severely agitated and aggressive patients in the ED when other parenteral sedation (benzodiazepines and antipsychotics) had failed on at least 2 occasions.

This was a prospective, observational study of patients who were given ketamine for sedation after failing other sedation attempts. Demographics, drug dose, observations and adverse effects were recorded. Primary outcome was the number of patients who failed to sedate within 120 minutes of ketamine administration or required further sedation within an hour. There were 12986 patients sedated as part of DORM || protocol (droperidol or midazolam) at two different hospitals during a 27 month period. 49 of these patients received ketamine after failing sedation. Median time to sedation was 20 minutes with a median dose of 300 mg ketamine. Adverse events occurred in 3 patients (6%) including vomiting and transient oxygen desaturation to 90%. The study concluded that ketamine was effective, did not cause obvious harm and is a viable option for patients who have failed sedation with benzodiazepines or antipsychotics. They recommend a dose of 4-5 mg/kg.

The group discussion centered around the fact that this study does not take into account the wide variety of causes of agitated delirium in these patients prior to sedating them with a universal agent. Should all causes be treated the same? The study also did not use similar patient groups, was not randomized nor blinded which contributes to its limitations. The consensus was however, that none of the patients had adverse outcomes (no deaths) and are discharged making ketamine a useful tool, though it can only be applied to patients in the ED. Also be aware of the potential complication of ketamine, laryngospasm, which can be treated with lidocaine.


Submitted by Dr. Ifat Sattar, PGY-1

A 32 year old female presented to a Midwest emergency department during one of the coldest weeks in January complaining of an allergic reaction. The high temperature that day was 10 degrees with a low of -3. The patient reported that while outside the day prior to presentation, she developed large red circles on the areas of her body that were exposed to the cold air.  The rash improved when she went inside. The next day, when she drank a cold beverage she felt like her throat was swelling and had difficulty breathing. She searched online for a possible explanation for her symptoms and discovered something called the ice challenge test and decided to try it on herself. She placed an ice cube on her arm and the same rash as the day before appeared on her arm. What is the patient experiencing?

Diagnosis: Cold Urticaria

Pathophysiology
Urticaria, also known as hives, are itchy, red papules that are circular in shape with pale centers.[1] Hives blanch with pressure and can last for minutes to days.[1] In cold urticaria, exposure to low temperature activates mast cells. Triggered mast cells release histamine and other inflammatory mediators leading to plasma leakage and vasodilation, which in turn creates hives and angioedema.[1] There are familial forms of cold urticaria, which are rare and associated with specific genetic mutations.[2] There are also idiopathic/acquired cases, which are more common. Symptoms are thought to be related to histamine release triggered by cold temperatures.[1]

Management
The most effective was to prevent cold urticaria is to avoid cold triggers. Patients should be advised to dress for the weather and stay inside when possible, as well as avoid cold beverages and cold emersion.[1] Similar to the treatment for other allergic reactions, first and second generation antihistamines such as diphenhydramine and loratadine can provide symptomatic relief for mild cases.[1] Systemic steroids may help with symptoms of itching, but have not been shown to be effective in preventing hive formation.[3] Anaphylactic shock may develop from cold urticaria and patients with severe symptoms may need to receive epinephrine in the ED along with diphenhydramine and steroids.[1] Patients that have experienced anaphylaxis to cold urticaria should be given epi-pens.

Diagnosis
Acquired cold urticaria can be diagnosed with a positive ice challenge test. To perform the test, an ice cube is placed on the subject's skin which is observed for the formation of hives. A positive test is noted when hives form under the area of ice contact within 15 minutes of exposure.[4] Ice cube challenge test is negative in familial forms for cold urticaria. Genetic testing may be performed to diagnose familial forms.[2]

Case Resolution
The patient improved symptomatically in the ED with Benadryl. She was instructed to take Benadryl for symptomatic relief and to avoid cold triggers. She was given follow up with an allergist.


References

1. Dresden C. Chapter 34: Urticaria and Angioedema. In: Andreoli TE, Cecil RL, eds. Andreoli and Carpenter's Cecil Essentials of Medicine. 23rd ed. Philadelphia, PA: Saunders'Elsevier;2008:1942-1946.
   
2. Hoffman HM, Wanderer AA, Broide DH. Familial cold autoinflammatory syndrome: phenotype and genotype of an autosomal dominant periodic fever. J Allergy Clin Immunol 2001;108:615-620.
3. Kobza Black A, Keahey TM, Eady RAJ, et al. Dissociation of histamine release and clinical improvement following treatment of acquired cold urticaria by prednisone. Br J Pharma 1981;12:327-331.
4. Neittaanma'ki H. Cold urticaria. Clinical findings in 220 patients. J Am Acad Dermatol 1985;13:636-644.

Submitted by Dr. Julia Hutchison, PGY-3

Case
A 27 year old male presents through triage complaining of shortness of breath. After obtaining the EKG shown below, he is taken back to a treatment room. What does the EKG show? Can you make a diagnosis? What are the next steps in management?

Background
An EKG is diagnostic only in few circumstances, i.e. STEMI, and always must be taken into the clinical context. However, there are certain EKGs an emergency physician must be able to identify and this is one of them. This EKG shows an irregularly irregular wide complex rhythm with various QRS morphologies and rates approaching 300 beats per minute. These are all clues to the diagnosis. First, there are not many causes of irregularly irregular rhythms, the most common by far being atrial fibrillation, but also multifocal atrial tachycardia and occasionally atrial flutter. Next, there is a wide complex rhythm. This may occur from conduction abnormalities (LBBB, RBBB) or sodium channel blockade (TCA overdose being a classic example). These both are fixed pathologies, and would not be expected to produce QRS complexes with various morphologies. Finally, rates approaching 300 beats per minute cannot be via AV nodal conduction. This must either be through an accessory pathway or from a ventricular focus. (1,2)

Considering the above, this EKG could either be polymorphic ventricular tachycardia or atrial fibrillation with aberrant conduction. However, as discussed AV nodal conduction is not possible, meaning an accessory pathway must be in play.

Diagnosis
Atrial fibrillation in the setting of Wolff-Parkinson-White (WPW) syndrome.

Pathophysiology
Recall that in WPW there is an accessory pathway which allows conduction to bypass the AV node. That is why when the atria are beating up to 500 beats per minute in atrial fibrillation it is able to conduct the produce such a high rate (if there is antidromic conduction, see figure below). Additionally, because of the timing and inconsistent depolarization, there are different QRS complexes seen.

AVRT with orthodromic (left) and antidromic (right) AV nodal conduction (2)
Life in the Fast Lane Pre-excitation Syndrome

Management
Management depends if the patient is stable or unstable. Unstable patients should undergo emergent synchronized cardioversion at 100 J to 200 J with sedation as appropriate. (1,3)  Stable patients can be considered for medical management. However, if the rhythm is unknown, it is always appropriate to treat as ventricular tachycardia and perform cardioversion, regardless of the stability of the patient. If WPW with aberrant conduction is suspected, it is important to avoid AV nodal blocking agents, such as adenosine, beta-blockers or calcium channel blockers, as they may promote conduction through the accessory pathway. This can lead to extremely high conduction rates and cause deterioration to ventriculat fibrillation. (1,3,4)

While the common anti-arrhythmic amiodarone may be thought of as first line, it is actually associated with deterioration to ventricular fibrillation and sudden death. (5-7)  Procainamide appears to be safe and effective in atrial fibrillation in WPW, and carries a slightly higher level of recommendation by the American Heart Association in the 2015 ACLS guidelines. (3)  Procainamide is also recommended in Tintinalli's Emergency Medicine, 8th edition, as well as in the 2015 guidelines from the American College of Cardiology/American Heart Association/European Society of Cardiology. (1,4)  It is dosed at a constant infusion of 20-50 mg/min until end points of hypotension, QRS duration increases by 50%, arrhythmia suppression or a maximum dose of 17 mg/kg is given. Maintenance infusion is 1-4 mg/min. Caution advised in cases of prolonged QT and CHF. (3)

Case Resolution
Your patients was unstable and was successfully cardioverted and had the follow up EKG below. Note the classic findings of WPW of short PR interval and a delta wave.

Summary
Recall the findings of atrial fibrillation with WPW

• Wide complete tachycardia
• Irregularly irregular rhythm
• Various QRS morphologies
• Rates near 300 bpm

Synchronized cardioversion for unstable and possibly for stable patients
If suspected, procainamide may be a better option than amiodarone

For more, see these great reviews from Life in the Fast Lane and Amal Mattu.


References

1. William Brady TL, Chris Ghaemmaghami. Cardiac Rhythm Disturbances. In: Tintinalli JE, Stapczynskj JS, Ma OJ, Yealy DM, Meckler GD, Cline DM, editor. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 8th ed. USA: McGraw-Hill Education; 2016.
2. Burns E. Wolff-Parkinson-White Syndrome. In: Lane LitF, editor.
3. Association AH. Part 7: Adult Advanced Cardiovascular Life Support. 2015.
4. Writing Committee M, Page RL, Joglar JA, et al. 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Heart Rhythm. 2016 Apr;13(4):e136-221.
5. Tijunelis MA, Herbert ME. Myth: Intravenous amiodarone is safe in patients with atrial fibrillation and Wolff-Parkinson-White syndrome in the emergency department. CJEM. 2005 Jul;7(4):262-5.
6. Simonian SM, Lotfipour S, Wall C, Langdorf MI. Challenging the superiority of amiodarone for rate control in Wolff-Parkinson-White and atrial fibrillation. Intern Emerg Med. 2010 Oct;5(5):421-6.
7. Tiago Luiz Luz Leiria AM, Rafeal de March Ronsoni, Leonardo Martins Pires, Marcelo Lapa Kruse, Gustavo Glotza de Lima. Ventricular Fibrillation during amiodarone infusion in a patient with Wolff-Parkinson
   

Submitted by Dr. Michael Craddick, PGY-2