Brian E. Driver

Use of esmolol after failure of standard cardiopulmonary resuscitation to treat patients with refractory ventricular fibrillation

INTRODUCTION We compare the outcomes for patients who received esmolol to those who did not receive esmolol during refractory ventricular fibrillation (RVF) in the emergency department (ED). METHODS A retrospective investigation in an urban academic ED of patients between January 2011 and January 2014 of patients with out-of-hospital or ED cardiac arrest (CA) with an initial rhythm of ventricular fibrillation (VF) or ventricular tachycardia (VT) who received at least three defibrillation attempts, 300mg of amiodarone, and 3mg of adrenaline, and who remained in CA upon ED arrival. Patients who received esmolol during CA were compared to those who did not. RESULTS 90 patients had CA with an initial rhythm of VF or VT; 65 patients were excluded, leaving 25 for analysis. Six patients received esmolol during cardiac arrest, and nineteen did not. All patients had ventricular dysrhythmias refractory to many defibrillation attempts, including defibrillation after administration of standard ACLS medications. Most received high doses of adrenaline, amiodarone, and sodium bicarbonate. Comparing the patients that received esmolol to those that did not: 67% and 42% had temporary return of spontaneous circulation (ROSC); 67% and 32% had sustained ROSC; 66% and 32% survived to intensive care unit admission; 50% and 16% survived to hospital discharge; and 50% and 11% survived to discharge with a favorable neurologic outcome, respectively. CONCLUSION Beta-blockade should be considered in patients with RVF in the ED prior to cessation of resuscitative efforts.

Diagnostic Performance of High Sensitivity Compared with Contemporary Cardiac Troponin I for the Diagnosis of Acute Myocardial Infarction

BACKGROUND We examined the diagnostic performance of high-sensitivity cardiac troponin I (hs-cTnI) vs contemporary cTnI with use of the 99th percentile alone and with a normal electrocardiogram (ECG) to rule out acute myocardial infarction (MI) and serial changes (deltas) to rule in MI. METHODS We included consecutive patients presenting to a US emergency department with serial cTnI onclinical indication. Diagnostic performance for acute MI, including MI subtypes, and 30-day outcomes were examined. RESULTS Among 1631 patients, MI was diagnosed in 12.9% using the contemporary cTnI assay and in 10.4% using the hs-cTnI assay. For ruling out MI, contemporary cTnI ≤99th percentile at 0, 3, and 6 h and a normal ECG had a negative predictive value (NPV) of 99.5% (95% CI, 98.6-100) and a sensitivity of 99.1% (95% CI, 97.4-100) for diagnostic and safety outcomes. Serial hs-cTnI measurements ≤99th percentile at 0 and 3 h and a normal ECG had an NPV and sensitivity of 100% (95% CI, 100-100) for diagnostic and safety outcomes. For ruling in MI, contemporary cTnI measurements had specificities of 84.4% (95% CI, 82.5-86.3) at presentation and 78.7% (95% CI, 75.4-82.0) with serial testing at 0, 3, and 6 h, improving to 89.2% (95% CI, 87.1-91.3) by using serial cTnI changes (delta, 0 and 6 h) >150%. hs-cTnI had specificities of 86.9% (95% CI, 85.1-88.6) at presentation and 85.7% (95% CI, 83.5-87.9) with serial testing at 0 and 3 h, improving to 89.3% (95% CI, 87.3-91.2) using a delta hs-cTnI (0 and 3 h) >5 ng/L. CONCLUSIONS hs-cTnI and contemporary cTnI assays are excellent in ruling out MI following recommendations predicated on serial testing and the 99th percentile with a normal ECG. For ruling in MI, deltas improve the specificity. ClinicalTrials.gov Identifier: NCT02060760.

Flush Rate Oxygen for Emergency Airway Preoxygenation

Study objective: Recent data suggest that emergency airway preoxygenation with a bag‐valve‐mask (BVM) device (held with a tight mask seal but without squeezing the bag) is superior to a nonrebreather (NRB) mask at standard oxygen flow rates. We seek to determine whether preoxygenation with an NRB mask with flush rate oxygen (>40 L/min by fully opening a standard oxygen flowmeter) is noninferior to BVM device with standard‐flow oxygen (15 L/min). We also seek to compare the efficacy of preoxygenation with NRB mask at flush rate oxygen with both NRB mask with oxygen at 15 L/min and simple mask at flush rate oxygen. Methods: We performed a crossover trial using healthy volunteers. In random sequence, subjects underwent 3‐minute trials of preoxygenation with nonrebreather mask with oxygen at 15 L/min (NRB‐15), nonrebreather mask with flush rate oxygen (NRB‐Flush), BVM device with oxygen at 15 L/min (BVM‐15), and simple mask with flush rate oxygen. The primary outcome measure was the FeO2 in a single exhaled breath. We compared the FeO2 of NRB‐Flush to other study groups, using a prespecified noninferiority margin of 10%. Results: We enrolled 26 subjects. Mean FeO2 values for NRB‐15, NRB‐Flush, BVM‐15, and simple mask with flush rate oxygen were 54% (95% confidence interval [CI] 50% to 57%), 86% (95% CI 84% to 88%), 77% (95% CI 74% to 81%), and 72% (95% CI 69% to 76%), respectively. FeO2 for NRB‐Flush was noninferior to BVM‐15 (difference 8%; 95% CI 5% to 11%). FeO2 for NRB‐Flush was higher than both NRB‐15 (FeO2 difference 32%; 95% CI 29% to 35%) and simple mask with flush rate oxygen (FeO2 difference 13%; 95% CI 10% to 17%). Conclusion: Preoxygenation with NRB‐Flush was noninferior to BVM‐15. NRB with flush rate oxygen may be a reasonable preoxygenation method for spontaneously breathing patients undergoing emergency airway management.

Unsuspected Critical Illness Among Emergency Department Patients Presenting for Acute Alcohol Intoxication

Study objective: Emergency department (ED) visits for acute alcohol intoxication are common, but this population is at risk for decompensation and occult critical illness. The purpose of this study is to describe the incidence and predictors of unsuspected critical illness among patients with acute alcohol intoxication. Methods: This was a retrospective observational study of ED patients from 2011 to 2016 with acute alcohol intoxication. The study cohort included patients presenting for alcohol intoxication, whose initial assessment was uncomplicated alcohol intoxication without any other active acute medical or traumatic complaints. The primary outcome was defined as the unanticipated subsequent use of critical care resources during the encounter or admission to an ICU. We investigated potential predictors for this outcome with generalized estimating equations. Results: We identified 31,364 eligible patient encounters (median age 38 years; 71% men; median breath alcohol concentration 234 mg/dL); 325 encounters (1%) used critical care resources. The most common diagnoses per 1,000 ED encounters were acute hypoxic respiratory failure (3.1), alcohol withdrawal (1.7), sepsis or infection (1.1), and intracranial hemorrhage (1.0). Three patients sustained a cardiac arrest. Presence of the following had an increased adjusted odds ratio (aOR) of developing critical illness: hypoglycemia (aOR 9.2), hypotension (aOR 3.8), tachycardia (aOR 1.8), fever (aOR 7.6), hypoxia (aOR 3.8), hypothermia (aOR 4.2), and parenteral sedation (aOR 2.4). The initial blood alcohol concentration aOR was 1.0. Conclusion: Critical care resources were used for 1% of ED patients with alcohol intoxication who were initially assessed by physicians to have low risk. Abnormal vital signs, hypoglycemia, and chemical sedation were associated with increased odds of critical illness.

A prospective study of ketamine as primary therapy for prehospital profound agitation

Objective: We investigated the effectiveness of ketamine as a primary therapy for prehospital profound agitation. Methods: This was a prospective observational study of patients receiving 5 mg/kg of intramuscular ketamine for profound agitation, defined as a score of + 4 on the Altered Mental Status Scale (AMSS), a validated ordinal scale of agitation from − 4 (unresponsive) to + 4 (most agitated). The primary outcome was time to adequate sedation (AMSS < + 1). Secondary outcomes included need for additional sedatives, intubation frequency, complications associated with ketamine, and mortality. Results: Forty‐nine patients were enrolled. Median age was 29 years (range 18–66); 76% (37/49) were male. Median time to adequate sedation was 4.2 min (95% CI: 2.5–5.9, range 1–25 min) and 90% (44/49) had adequate sedation prehospital. Seven patients (14%) received a second sedative prehospital. Intubation occurred in 57% (28/49) of patients. Mechanical ventilation lasted < 24 h in 82% (23/28) of patients, and < 48 h in 96% (27/28) of patients. A single physician intubated 36% (10/28) of the patients. Complications related to ketamine included hypersalivation (n = 9, 18%), vomiting (n = 3, 6%), and emergence reaction (n = 2, 4%). One patient died from complications of septic shock on hospital day 29, likely unrelated to ketamine. Conclusions: In patients with prehospital profound agitation, ketamine provides rapid effective sedation when used as a primary therapy. Intubation was common but accompanied by a short duration of mechanical ventilation and appears to have been subject to individual physician practice variation.

Definitive airway management in emergency department patients with a King laryngeal tube™ in place: a simple and safe approach.

To the Editor, We read with interest the article by Subramanian et al. describing their experience with definitive airway management in 48 patients arriving at the emergency department (ED) with a King LT(S)-D laryngeal tube (KingLT) placed by pre-hospital personnel. We agree that there are potential complications associated with removing the KingLT in such patients. We were surprised, however, at the proportion of patients requiring surgical airway management [14 (29%) patients] and airway techniques [i.e., tube exchange catheter or flexible bronchoscopy, 14 (29%)] beyond direct (DL) or video (VL) laryngoscopy. We therefore offer a summary of our own experience with such patients and suggest a simple, non-surgical technique for exchanging the KingLT for an endotracheal tube (ETT). Over a similar five-year period (2010-2015), a total of 454 patients arrived at our Level 1 trauma centre ED with a KingLT in situ. A survey of our faculty revealed that 453 (99.8%) patients had a definitive airway secured by emergency physicians with non-surgical techniques (Table). The most common definitive airway technique for patients with the KingLT in place was VL-guided endotracheal intubation without removing the device. We recently described this technique in detail, and we summarize it here. We believe that the simplest way to intubate with the KingLT (King Systems; Noblesville, IN, USA) in situ is to use VL and a bougie. During the first portion of the procedure, the KingLT balloons remain inflated, and ventilation through the device is ongoing. The first step is to place the VL blade anterior to the KingLT, advancing it along the tongue until the oropharyngeal balloon is well visualized (Figure A). The KingLT balloons are then deflated, allowing visualization of the glottic structures on the VL monitor. A bougie can then be advanced into the trachea followed by an ETT (Figure B-D). Unlike DL, VL consistently allows good visualization of the glottis with the KingLT in situ. Also, in rare cases of failed intubation, the KingLT remains in a functional position, and the balloons can be immediately re-inflated and ventilation resumed. In summary, our experience is that conventional nonsurgical techniques (most often VL) can be used to secure a definitive airway in nearly every patient arriving at the ED with a KingLT in place. We believe that the safest technique for managing such patients is to intubate endotracheally using VL and then place a bougie while the KingLT remains in position. This technique is simple, intuitive, and utilizes airway equipment that is readily available in most EDs and operating suites. This letter is accompanied by a reply. Please see Can J Anesth 2016; 63: this issue.

Emergency Department Airway Management of Severe Angioedema: A Video Review of 45 Intubations

Study objective Angioedema is an uncommon but important cause of airway obstruction. Emergency airway management of angioedema is difficult. We seek to describe the course and outcomes of emergency airway management for severe angioedema in our institution. Methods We performed a retrospective, observational study of all intubations for angioedema performed in an urban academic emergency department (ED) between November 2007 and June 2015. We performed a structured review of video recordings of each intubation. We identified the methods of airway management, the success of each method, and the outcomes and complications of the effort. Results We identified 52 patients with angioedema who were intubated in the ED; 7 were excluded because of missing videos, leaving 45 patients in the analysis. Median time from arrival to the ED to the first intubation attempt was 33 minutes (interquartile range 17 to 79 minutes). Nasotracheal intubation was the most common first method (33/45; 73%), followed by video laryngoscopy (7/45; 16%). Two patients required attempts at more invasive airway procedures (retrograde intubation and cricothyrotomy). The intubating laryngeal mask airway was used as a rescue method 5 times after failure of multiple methods, with successful oxygenation, ventilation, and intubation through the laryngeal mask airway in all 5 patients. All patients were successfully intubated. Conclusion In this series of ED patients who were intubated because of angioedema, emergency physicians used a range of methods to successfully manage the airway. These observations provide key lessons for the emergency airway management of these critical patients.

Apnea After Low-Dose Ketamine Sedation During Attempted Delayed Sequence Intubation

Some patients are agitated and unable to tolerate conventional preoxygenation methods, including face mask oxygen or noninvasive positive-pressure ventilation. Sedation with ketamine for preoxygenation, also known as delayed sequence intubation, is a technique that can be used to achieve preoxygenation in this patient population. No complications of delayed sequence intubation have previously been reported. A 60-year-old woman presented with acute hypoxic respiratory failure. Despite application of high-flow oxygen (60 L/min) with a nonrebreather face mask, her oxygen saturation remained at 93%. She would not accept a noninvasive positive-pressure ventilation mask, although she remained alert, with vigorous respiratory effort. She received 25 mg of intravenous ketamine (0.31 mg/kg) to allow application of noninvasive positive-pressure ventilation. One minute after receiving ketamine, she developed apnea; bag-valve-mask ventilation was initiated, and she received succinylcholine and etomidate and was intubated on the first attempt, without complication. She had no respiratory effort between the onset of apnea and pharmacologic paralysis. Apnea can occur in critically ill patients who receive ketamine to facilitate preoxygenation. Sedation remains a valuable technique to enable optimal preoxygenation in agitated patients; however, clinicians should not perform this technique lightly and should be prepared to secure the patients airway immediately.

The Bougie and First-Pass Success in the Emergency Department

Study objective: The bougie may improve first‐pass intubation success in operating room patients. We seek to determine whether bougie use is associated with emergency department (ED) first‐pass intubation success. Methods: We studied consecutive adult ED intubations at an urban, academic medical center during 2013. Intubation events were identified by motion‐activated video recording. We determined the association between bougie use and first‐pass intubation success, adjusting for neuromuscular blockade, video laryngoscopy, abnormal airway anatomy, and whether the patient was placed in the sniffing position or the head was lifted off the bed during intubation. Results: Intubation with a Macintosh blade was attempted in 543 cases; a bougie was used on the majority of initial attempts (80%; n=435). First‐pass success was greater with than without bougie use (95% versus 86%; absolute difference 9% [95% confidence interval {CI} 2% to 16%]). The median first‐attempt duration was higher with than without bougie (40 versus 27 seconds; difference 14 seconds [95% CI 11 to 16 seconds]). Bougie use was independently associated with greater first‐pass success (adjusted odds ratio 2.83 [95% CI 1.35 to 5.92]). Conclusion: Bougie was associated with increased first‐pass intubation success. Bougie use may be helpful in ED intubation.

Effect of Use of a Bougie vs Endotracheal Tube and Stylet on First-Attempt Intubation Success Among Patients With Difficult Airways Undergoing Emergency Intubation: A Randomized Clinical Trial.

Importance The tracheal tube introducer, known as the bougie, is typically used to aid tracheal intubation in poor laryngoscopic views or after intubation attempts fail. The effect of routine bougie use on first-attempt intubation success is unclear. Objective To compare first attempt intubation success facilitated by the bougie vs the endotracheal tube + stylet. Design, Setting, and Patients The Bougie Use in Emergency Airway Management (BEAM) trial was a randomized clinical trial conducted from September 2016 through August 2017 in the emergency department at Hennepin County Medical Center, an urban, academic department in Minneapolis, Minnesota, where emergency physicians perform all endotracheal intubations. Included patients were 18 years and older who were consecutively admitted to the emergency department and underwent emergency orotracheal intubation with a Macintosh laryngoscope blade for respiratory arrest, difficulty breathing, or airway protection. Interventions Patients were randomly assigned to undergo the initial intubation attempt facilitated by bougie (n = 381) or endotracheal tube + stylet (n = 376). Main Outcomes and Measures The primary outcome was first-attempt intubation success in patients with at least 1 difficult airway characteristic (body fluids obscuring the laryngeal view, airway obstruction or edema, obesity, short neck, small mandible, large tongue, facial trauma, or the need for cervical spine immobilization). Secondary outcomes were first-attempt success in all patients, first-attempt intubation success without hypoxemia, first-attempt duration, esophageal intubation, and hypoxemia. Results Among 757 patients who were randomized (mean age, 46 years; women, 230 [30%]), 757 patients (100%) completed the trial. Among the 380 patients with at least 1 difficult airway characteristic, first-attempt intubation success was higher in the bougie group (96%) than in the endotracheal tube + stylet group (82%) (absolute between-group difference, 14% [95% CI, 8% to 20%]). Among all patients, first-attempt intubation success in the bougie group (98%) was higher than the endotracheal tube + stylet group (87%) (absolute difference, 11% [95% CI, 7% to 14%]). The median duration of the first intubation attempt (38 seconds vs 36 seconds) and the incidence of hypoxemia (13% vs 14%) did not differ significantly between the bougie and endotracheal tube + stylet groups. Conclusions and Relevance In this emergency department, use of a bougie compared with an endotracheal tube + stylet resulted in significantly higher first-attempt intubation success among patients undergoing emergency endotracheal intubation. However, these findings should be considered provisional until the generalizability is assessed in other institutions and settings. Trial Registration clinicaltrials.gov Identifier: NCT02902146