Robert F. Reardon

Echocardiographic evaluation of TASER X26 probe deployment into the chests of human volunteers

Several animal studies have shown that the TASER X26 (TASER International, Scottsdale, Ariz) conducted electrical weapon can electrically capture the myocardium when discharged on the thorax. These results have not been reproduced in human echocardiographic studies. A primary limitation of those human studies is that the TASER device was connected by taping the wires into conductive gel on the skin surface of the thorax. This study overcomes those limitations. In this study, a training instructor discharged a TASER X26 into the chests of 10 subjects from a distance of 7 ft so that a 5-second discharge could be administered through the probes as in field exposures. Limited echocardiography was performed before, during, and after discharge. In agreement with 2 prior studies by these authors, the TASER X26 did not electrically capture the human myocardium when used with probe deployment. These data are contrary to animal studies in which capture occurred.

Face Mask Ventilation: A Comparison of Three Techniques

BACKGROUND There are multiple techniques for face-mask (FM) ventilation. To our knowledge, the one-handed vs. two-handed C-E technique has been compared in children and adults, but no studies have compared the various two-handed methods. OBJECTIVE To compare the effectiveness of mask seal using three different FM techniques on a model intended to simulate difficult FM ventilation and measure ventilation performance. METHODS This was a prospective randomized study of health care providers. A standard airway-training mannequin was modified to produce variable airway resistance and allow measurements of ventilation volume and pressure. Each subject performed FM ventilation for 3 min per technique (30 breaths) in a randomized order. Median exhaled tidal volume and proximal peak flow pressure were determined and compared. RESULTS Seventy subjects were enrolled. Both two-handed ventilation techniques were more effective than the one-handed technique by both volume and pressure measurements. The one-handed C-E technique yielded a median volume of 428.4 mL, vs. the two-handed C-E technique with 550.8 mL, and the two-handed V-E technique with 538 mL (p < 0.001). Peak pressure measurements revealed a median of 54.6 cm H2O for the one-handed C-E technique, 66 cm H2O for the two-handed C-E technique, and 66.6 cm H2O for the two-handed V-E technique (p < 0.001). There was not a difference between the various two-handed techniques. CONCLUSIONS This model for FM ventilation is able to differentiate the efficacy of FM techniques. Both two-handed ventilation methods were superior to one-handed ventilation, both of which should perhaps be included in airway training for health care providers.

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.

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.

An evaluation of two conducted electrical weapons using a swine comparative cardiac safety model

Arrest-related deaths proximate to the use of a conducted electrical weapon (CEW) continue to generate controversy despite a better understanding of the multi-factorial nature of many of these deaths. With the rapid adoption of this technology by law enforcement, and the proliferation of companies entering the marketplace, it is important to have a method to assess the relative safety of these weapons. We had previously developed a model to assess the relative cardiac safety of CEWs. In this study, we use this model to compare the TASER X2 and the Karbon Arms MPID. Our results suggest that the TASER X2 may have an improved cardiac safety margin over the Karbon Arms MPID as determined by a smaller area of cardiac pacing on the anterior chest in our model. This model seems to offer a reproducible means of comparing the cardiac effects of CEWs.

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

Retrograde Intubation with an Extraglottic Device in Place

BACKGROUND The intubating laryngeal mask airway (ILMA) is an extraglottic device with a high rate of successful ventilation and oxygenation. Most modern airway algorithms suggest using an extraglottic device as the first-line rescue technique for a failed airway in emergency airway management. Eventually, a more secure airway is needed if the extraglottic temporizing device is working well. Retrograde intubation is a surgical airway management technique that is effective but relatively slow, making it most useful when ventilation can be maintained during the procedure. CASE REPORT We report 2 cases of difficult emergency airway management with an ILMA used initially and retrograde intubation later used to establish a more secure airway. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Retrograde incubation can be performed with an LMA in place for complicated airway management.

A Novel Technique for a Difficult Breech Delivery

BACKGROUND Breech presentation and delivery are important complications of labor and delivery, which, although dealt with by the emergency physician infrequently, can represent major morbidity and mortality to both the mother and fetus if techniques are not performed correctly. OBJECTIVES We aim to describe a technique for breech delivery that was used successfully when all conventional techniques had failed. To our knowledge, this technique has not been described in previous literature. CASE REPORT A 36-year-old woman presented to an urban emergency department in active labor. The physicians were called to the triage area, and found the patient lying on the floor with a limp, cyanotic-appearing fetus delivered to the level of the mid thorax. The arms and shoulders were delivered successfully, but after all traditional maneuvers to deliver the head were unsuccessful, a novel approach was used successfully and is described in this report. CONCLUSION We have described a novel, seemingly safe, and effective technique to use in breech delivery when traditional techniques have failed.