An ideal model for out-of-hospital airway management?
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Airway Obstruction↗
Biomedical subjects
Henry E Wang
Publications and source records attributed to Henry E Wang.
Does the type of out-of-hospital airway interfere with other cardiopulmonary resuscitation tasks?
BACKGROUND: Out-of-hospital rescuers often perform tracheal intubation (TI) prior to other cardiopulmonary resuscitation (CPR) interventions. TI is a complex and error-prone procedure that may interfere with other key resuscitation tasks. We compared the effects of TI versus esophageal tracheal combitube (ETC) insertion on the accomplishment of other interventions during simulated cardiopulmonary resuscitation. METHODS: In this prospective trial using a human simulator, two-paramedic teams simulated resuscitation of a ventricular fibrillation cardiopulmonary arrest using standard Advanced Cardiac Life Support guidelines. In each of two trials, teams used either TI or ETC as the primary airway device. Following delivery of three rescue shocks, we measured time intervals to successful airway placement, intravenous (IV) line insertion, drug administration, delivery of fourth rescue shock and completion of all four tasks. We also measured the total time without chest compressions. We compared task completion times using non-parametric statistics (Wilcoxon signed-ranks test) with a Bonferroni-adjusted p-value of 0.008. RESULTS: Twenty teams each completed two scenarios. Participants required a median of 172.5 s (IQR: 146.5-225.5) to accomplish all four tasks. Elapsed time to airway placement was significantly less for ETC than TI (median difference 26.5 s (IQR 13-44.5), p=0.002). Time without chest compressions was less for ETC than TI (median difference 8.5 s (IQR 2.5-23.5), p=0.005). There were no differences between ETC and TI in times to IV placement (median difference 23.5 s (IQR -20 to 61), p=0.11), drug delivery (39.5 s (IQR -18 to 63), p=0.07), delivery of fourth rescue shock (39.5 s (IQR -21.5 to 87.5), p=0.07) or completion of all four tasks (33 s (IQR -11 to 74.5), p=0.08). CONCLUSION: Compared with TI, ETC reduced time to airway placement and time without chest compressions, but did not affect elapsed times to accomplish other interventions. Additional time differences may be realized if translated to clinical out-of-hospital conditions.
Cardiopulmonary Resuscitation↗
Limited opportunities for paramedic student endotracheal intubation training in the operating room.
BACKGROUND: Paramedics, who often are the first to provide emergency care to critically ill patients, must be proficient in endotracheal intubation (ETI). Training in the controlled operating room (OR) setting is a common method for learning basic ETI technique. OBJECTIVES: To determine the quantity and nature of OR ETI training currently provided to paramedic students. METHODS: The authors surveyed directors of paramedic training programs accredited by the Commission on Accreditation of Allied Health Education Programs. An anonymous 12-question, structured, closed-response survey instrument was used that requested information regarding the duration and nature of OR training provided to paramedic students. The results were analyzed by using descriptive statistics. RESULTS: From 192 programs, 161 completed surveys were received (response rate, 85%). OR training was used at 156 programs (97%) but generally was limited (median, 17-32 hours per student). Half of the programs provided fewer than 16 OR hours per student. Students attempted a limited number of OR ETI (median, 6-10 ETI). Most respondents (61%) reported competition from other health care students for OR ETI. Other identified hindering factors included the increasing OR use of laryngeal mask airways and physicians' medicolegal concerns. Respondents from 52 (33%) programs reported a recent reduction in OR access, and 56 (36%) programs expected future OR opportunities to decrease. CONCLUSIONS: Despite its key role in airway management education, the quantity and nature of OR ETI training that is available to paramedic students is limited in comparison to that available to other ETI providers.
Emergency Medical Technicians↗
A randomized comparison of manual, mechanical and high-impulse chest compression in a porcine model of prolonged ventricular fibrillation.
BACKGROUND: Elevated coronary perfusion pressure (CPP) during CPR is associated with return of spontaneous circulation (ROSC). We compared CPP achieved with three methods of chest compression: manual (MAN), mechanical (MECH) and high-impulse mechanical (HI) in a porcine model of prolonged ventricular fibrillation (VF). We hypothesized that HI (very rapid acceleration of the down-stroke) would produce greater CPPs than MAN or MECH, and that HI would also produce a higher rate of ROSC. METHODS: Twenty-eight domestic swine (mean 27.8 kg) were randomly assigned to three methods of chest compression. Animals were instrumented under anesthesia, and VF was induced and untreated for 8 min. After 2 min of CPR, epinephrine (adrenaline) (0. 1 mg/kg), vasopressin (40 U) and propranolol (1.0 mg) were administered. CPR continued for three more minutes, after which up to three rescue shocks were delivered. CPP was determined in an automated fashion by measuring the difference between aortic and right atrial pressures 0.1s prior to the down-stroke of each compression (i.e. end-relaxation). ROSC was defined as a systolic pressure greater than 80 mmHg sustained for at least 1 min. We analyzed CPP and ROSC using repeated measures ANOVA and Fisher's exact test. RESULTS: Over the 5 min of CPR, CPP increased more with HI compression than with MAN compression (p=0.017). ROSC was attained in 4/9 MAN, 6/9 MECH and 10/10 HI (HI versus MAN p=0.01). CONCLUSIONS: Over the course of CPR, HI compression increased CPP more than MAN compression. HI compression produced a significantly higher rate of ROSC than MAN, but not MECH compression.
Adrenergic alpha-Agonists↗
How many attempts are required to accomplish out-of-hospital endotracheal intubation?
BACKGROUND: An important goal of emergency airway management is to complete endotracheal intubation (ETI) correctly, safely, and quickly, and repeated ETI attempts can increase patient morbidity and mortality. Clinical protocols limiting the number of ETI attempts may minimize harm, but this strategy also may reduce the frequency of successful ETI. OBJECTIVES: To characterize the relationship between the number of out-of-hospital ETI attempts and ETI success. METHODS: This study used prospective, multicenter data from 42 emergency medical services agencies from an 18-month period. Out-of-hospital rescuers (paramedics, out-of-hospital nurses, and physicians) completed structured, closed-response data forms describing clinical methods, course, and outcomes for all ETIs. An ETI attempt was defined as an insertion of the laryngoscope blade. Rescuers identified ETI outcome (success or failure) for each attempt. The authors defined overall success as ETI outcome (success or failure) on the last attempt, examining cardiac arrest, conventional nonarrest, sedation-facilitated, and rapid-sequence ETI separately. Univariate odds ratios (ORs) were used to identify the number of ETI attempts in which the cumulative ETI success rate approached the overall ETI success rate. RESULTS: Complete data were available for 1,941 cases. More than 30% of patients received more than one ETI attempt. For 1,272 cardiac arrest ETIs, cumulative success for the first three attempts were 69.9%, 84.9%, and 89.9%; cumulative success approached overall success (91.8%) after three attempts (OR, 0.79; 95% confidence interval [CI] = 0.61 to 1.04). For 463 conventional non-arrest ETIs, cumulative success for the first three attempts were 57.6%, 69.2%, and 72.7%; cumulative success approached overall success (73.7%) after two attempts (OR, 0.95; 95% CI = 0.71 to 1.28). For 126 sedation-facilitated ETIs, cumulative success for the first three attempts were 44.4%, 62.7%, and 75.4%; cumulative success approached overall success (77.0%) after three attempts (OR, 0.92; 95% CI = 0.51 to 1.64). For 80 rapid-sequence ETI, cumulative ETI success for the first three attempts were 56.3%, 81.3%, and 91.3%; cumulative success approached overall success (96.3%) after three attempts (OR, 0.41; 95% CI = 0.10 to 1.65). CONCLUSIONS: Out-of-hospital rescuers often require multiple attempts to accomplish ETI. A protocol limit of three attempts offers reasonable opportunity for accomplishing ETI within the constraints of the out-of-hospital environment.
Clinical Competence↗
Out-of-hospital endotracheal intubation: where are we?
While remaining prominent in paramedic care and beneficial to some patients, out-of-hospital endotracheal intubation has not clearly improved survival or reduced morbidity from critical illness or injury when studied more broadly. Recent studies identify equivocal or unfavorable clinical effects, adverse events and errors, interaction with other important resuscitation interventions, and challenges in providing and maintaining procedural skill. We provide an overview of current data evaluating the overall effectiveness, safety, and feasibility of paramedic out-of-hospital endotracheal intubation. These studies highlight our limited understanding of out-of-hospital endotracheal intubation and the need for new strategies to improve airway support in the out-of-hospital setting.
Allied Health Personnel↗
A case of conversion disorder presenting as a severe acute stroke.
Conversion disorders often present with dramatic physical presentations suggestive of severe organic disease. We present the case of a young woman who presented to the Emergency Department with a dense left hemiparesis suggestive of a severe acute stroke. Emergent referral to a regional stroke center facilitated rapid medical evaluation, exclusion of organic disease, and confirmation of conversion disorder as the etiology for the symptoms. This report highlights the dramatic clinical presentations that may result from conversion disorders as well as the benefits of rapid medical evaluation by specialty stroke centers.
Adult↗
Ten years of clinical experience with adult meningitis at an urban academic medical center.
The purpose of this study is to describe the clinical presentation and bacteriology of adult patients admitted to an urban academic medical center with bacterial meningitis over a 10-year period. In this retrospective review, we identified all adult patients discharged from a tertiary care facility between November 1992 and March 2003 with a diagnosis of bacterial meningitis. Data regarding demographics, vital signs, presenting symptoms, seven predisposing factors, body fluid cultures, cerebrospinal fluid (CSF) findings, and mortality were abstracted. Data were analyzed using descriptive methods. We identified 38 cases. Overall mortality rate was 18.4% (95% confidence interval 7.7-34.3%). The most common of the seven predisposing factors was an immunocompromised state (31.6%). Streptococcus pneumoniae (24.3%), other streptococcus species (24.3%), and Gram-negative rods (16.2%) were the most commonly identified organisms. The classic meningitis triad (fever, neck stiffness, mental status change or headache) was present in only 21.1% of cases. CSF analysis demonstrated WBC >or= 100/mm3 in 81.3%, decreased glucose (< 50 mg/dL) in 50%, and elevated protein (> 45 mg/dL) in 91.2%. With increasing numbers of immunocompromised patients, atypical presentations of bacterial meningitis seem to be more common. A higher percentage of bacterial meningitis cases seem to be caused by Gram-negative rods and Streptococcus species other than Streptococcus pneumoniae. The classic meningitis triad occurred in fewer cases than previously described.
Academic Medical Centers↗
Human patients or simulators for teaching endotracheal intubation: whom are we fooling?
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Emergency Medical Technicians↗
Clinical policy on pediatric procedural sedation.
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Analgesics↗
Differential effects of out-of-hospital interventions on short- and long-term survival after cardiopulmonary arrest.
AIM: The aim of this study was to describe the relationship between prehospital clinical variables, interventions and survival time after cardiac arrest and to determine whether various factors affect the risk of death differently at early and late time periods. METHODS: Time-to-death (days) after collapse was identified using the paramedic record, the social security death index or obituaries for adult (> or =18 years) out-of-hospital cardiac arrest (OOHCA) cases from Pittsburgh, Pennsylvania between 1998 and 2002. Clinical prehospital variables included age of patient, sex, witnessed collapse, bystander CPR, use of an automated external defibrillator (AED), initial ECG rhythm, medications and response time intervals. We used Cox regression with time varying coefficients to describe the effects of each covariate separately upon short-term (on day 1) and long-term (after day 1) survival. RESULTS: Of 1496 adult patients, overall mortality was 89.5%. The majority (75%) of deaths occurred on day 1. Of the 1339 deaths, 1213 (90.6%) occurred by day 3, 1272 (95.0%) occurred by day 7 and 1299 (97.0%) occurred by day 14. Witnessed collapse (hazard ratio 0.85; 95% CI: 0.75-0.97) or the use of epinephrine (adrenaline) (1.57; 1.20-2.07), lidocaine (0.78; 0.66-0.91) or dopamine (0.75; 0.56-1.00) were independently associated with risk of death on day 1 (day of collapse). Epinephrine use (1.84; 1.23-2.78) and age (1.02; 1.01-1.03) were independently associated with risk of death after day 1. The proportional hazards assumption was satisfied. CONCLUSIONS: Survival after out-of-hospital cardiac was characterized by a large number of deaths on day 1. Most subsequent deaths were identified within 14 days after collapse. Prehospital factors have markedly different relationships with short- and long-term survival. Linkage between prehospital intervention and short- and long-term outcomes must consider the survival time characteristics of this population.
Adult↗
Admission hypothermia and outcome after major trauma.
OBJECTIVE: Uncontrolled exposure hypothermia is believed to be deleterious in the setting of major trauma. Prevention of hypothermia in the injured patient is currently practiced in both prehospital and in-hospital settings. However, this standard is based on studies of limited patient series that were not designed to identify the independent relationship between hypothermia and mortality. Recent studies suggest that therapeutically applied hypothermia may benefit selected patient subsets. The goal of this study was to evaluate the independent association between admission hypothermia and mortality after major trauma, with adjustment for clinical confounders. DESIGN: Retrospective analysis of a statewide trauma registry. The primary outcome was death at hospital discharge. The key exposure was hypothermia, defined as body temperature </=35 degrees C at admission. Multivariate regression was used to risk-adjust for age, severity and mechanism of injury, and route of temperature measurement. Additional adjustment for prehospital exposure time and intravenous fluid therapy was also evaluated. SETTING: Trauma centers of the Commonwealth of Pennsylvania. PATIENTS: All trauma patients >/=16 yrs of age for the years 2000-2002. Transferred patients were excluded. Patients were excluded if temperature or route of temperature measurement was not known. Both the full cohort and a subset with isolated severe head injury were evaluated. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 38,520 patients, 1,921 (5.0%) were hypothermic at admission. Admission hypothermia was independently associated with increased odds of death in both the full cohort (odds ratio, 3.03; 95% confidence interval, 2.62-3.51) and the subset with isolated severe head injury (2.21; 1.62-3.03), with adjustment for age, severity and mechanism of injury, and route of temperature measurement. CONCLUSIONS: Admission hypothermia is independently associated with increased adjusted odds of death after major trauma. The increase in mortality is not completely attributable to physiologic presentation or injury pattern or severity.
Adolescent↗
Procedural experience with out-of-hospital endotracheal intubation.
OBJECTIVE: Out-of-hospital rescuers likely need regular clinical experience to perform endotracheal intubation (ETI) in a safe and effective manner. We sought to determine the frequency of ETI performed by individual out-of-hospital rescuers. DESIGN: Analysis of an administrative database of all emergency medical services (EMS) patient care reports in Pennsylvania. SETTING: Commonwealth of Pennsylvania from January 1 to December 31, 2003. SUBJECTS: EMS advanced life support rescuers (paramedics, prehospital nurses, and EMS physicians) who reported at least one patient contact during the study period. INTERVENTIONS: None. MEASUREMENTS: We calculated individual rescuer ETI frequency and opportunity. We evaluated relationships between ETI frequency and the number of patient contacts. We also examined the relationship with practice setting (air medical vs. ground rescuers and urban vs. rural rescuers). MAIN RESULTS: In 1,544,791 patient care reports, 11,484 ETIs were reported by 5,245 out-of-hospital rescuers. The median ETI frequency was one (interquartile range, 0-3; range, 0-23). Of 5,245 rescuers, >67% (3,551) performed two or fewer ETIs, and >39% (2,054) rescuers did not perform any ETIs. The median number of ETI opportunities was three (interquartile range, 0-6; range, 0-76). ETI frequency was associated with patient volume (Spearman's rho = 0.67) and was higher for air medical (p = .006) and urban (p < .0001) rescuers. ETI frequency was not associated with response (Spearman's rho = -0.01) or transport (Spearman's rho = -0.06) times. CONCLUSIONS: Out-of-hospital ETI, an important and difficult resuscitation intervention, is an uncommon event for most rescuers.
Clinical Competence↗
Out-of-hospital endotracheal Intubation--it's time to stop pretending that problems don't exist.
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Airway Obstruction↗
Ventricular fibrillation scaling exponent can guide timing of defibrillation and other therapies.
BACKGROUND: The scaling exponent (ScE) of the ventricular fibrillation (VF) waveform correlates with duration of VF and predicts defibrillation outcome. We compared 4 therapeutic approaches to the treatment of VF of various durations. METHODS AND RESULTS: Seventy-two swine (19.5 to 25.7 kg) were randomly assigned to 1 of 9 groups (n=8 each). VF was induced and left untreated until the ScE reached 1.10, 1.20, 1.30, or 1.40. Animals were treated with either immediate countershock (IC); 3 minutes of CPR before the first countershock (CPR); CPR for 2 minutes, then drugs given with 3 more minutes of CPR before the first shock (CPR-D); or drugs given at the start of CPR with 3 minutes of CPR before the first shock (Drugs+CPR). Return of spontaneous circulation (ROSC) and 1-hour survival were analyzed with chi2 and Kaplan-Meier survival curves. IC was effective when the ScE was low but had decreasing success as the ScE increased. No animals in the 1.30 or 1.40 groups had ROSC from IC (0 of 16). CPR did not improve first shock outcome in the 1.20 CPR group (3 of 8 ROSC). Kaplan-Meier survival analyses indicated that IC significantly delayed time to ROSC in both the 1.3 (P=0.0006) and the 1.4 (P=0.005) groups. CONCLUSIONS: VF of brief to moderate duration is effectively treated by IC. When VF is prolonged, as indicated by an ScE of 1.3 or greater, IC was not effective and delayed time to ROSC. The ScE can help in choosing the first intervention in the treatment of VF.
Animals↗
Out-of-hospital endotracheal intubation and outcome after traumatic brain injury.
STUDY OBJECTIVE: Previous studies disagree about the effect of out-of-hospital endotracheal intubation on traumatic brain injury. This study compares the effects of out-of-hospital endotracheal intubation versus emergency department (ED) endotracheal intubation on mortality and neurologic and functional outcome after severe traumatic brain injury. METHODS: From the 2000 to 2002 Pennsylvania Trauma Outcome Study (a registry of all patients treated at trauma centers in the Commonwealth of Pennsylvania), adult patients with head/neck Abbreviated Injury Scale score of 3 or greater and undergoing out-of-hospital endotracheal intubation or ED endotracheal intubation were included. Transferred patients were excluded. The primary outcome was death (on hospital discharge). The secondary outcomes were neurologic (good versus poor, inferred from discharge to home versus long-term care facility) and functional outcome (determined from a Functional Impairment Score). The key exposure was endotracheal intubation (out-of-hospital endotracheal intubation versus ED endotracheal intubation). Using multivariate logistic regression, odds estimates for out-of-hospital endotracheal intubation were adjusted using age, sex, head/neck Abbreviated Injury Scale score, Injury Severity Score, mechanism of injury (penetrating versus blunt), admission systolic blood pressure, mode of transport (ground only versus helicopter or helicopter + ground), and the use of out-of-hospital neuromuscular blocking agents. A propensity score adjustment accounted for the potential effects of preexisting conditions, inhospital complications, and social factors (drug and alcohol use, race, and insurance coverage). RESULTS: There were 4,098 patients with head/neck Abbreviated Injury Scale score of 3 or greater who received either out-of-hospital endotracheal intubation (n=1,797, 43.9%) or ED endotracheal intubation (n=2,301, 56.1%). Adjusted odds of death were higher for out-of-hospital endotracheal intubation than ED endotracheal intubation (odds ratio [OR] 3.99; 95% confidence interval [CI] 3.21 to 4.93). Out-of-hospital endotracheal intubation was associated with an increased adjusted odds of poor neurologic outcome (OR 1.61; 95% CI 1.15 to 2.26), moderate or severe functional impairment (Functional Impairment Score 6 to 15; OR 1.92; 95% CI 1.40 to 2.64), and severe functional impairment (Functional Impairment Score 11 to 15; OR 1.80; 95% CI 1.29 to 2.52). CONCLUSION: Out-of-hospital endotracheal intubation was associated with adverse outcomes after severe traumatic brain injury. The implications for current clinical care remain undefined.
Adolescent↗
Out-of-hospital rapid-sequence intubation for trauma patients.
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Allied Health Personnel↗
Preliminary experience with a prospective, multi-centered evaluation of out-of-hospital endotracheal intubation.
STUDY OBJECTIVE: Previous out-of-hospital airway management data are limited by small, single-site designs. We sought to evaluate the feasibility of performing a prospective, multi-centered evaluation of out-of-hospital endotracheal intubation (ETI) using a standardized data collection tool. METHODS: We designed a prospective multi-centered observational study involving 45 advanced life support (ALS) services from a mid-Atlantic state. Using a standardized data form, prehospital personnel reported details of each attempted ETI, including patient demographics, methods used, difficulties encountered, and initial patient outcomes. We calculated and assessed data form return rates (using independent queries of the number of ETI attempted by each EMS service) and missing data entry rates. We also performed preliminary cross-sectional assessments of factors of current interest in out-of-hospital ETI. Accuracy and validity of responses were not evaluated. Data were stored centrally and analyzed using descriptive techniques. RESULTS: Participants included 8 urban, 15 suburban, 20 rural, and 2 air medical services. Data forms were received on 783 adults receiving ETI attempts during the study period June 1, 2001-November 30, 2001. The pooled data form return rate was 72.7%. Per-service return rates ranged from 0 to 100% and the median per-service return rate was 75%. Non-response (data form not returned for attempted intubation) was problematic, with nine services demonstrating data return rates less than 50%. Data return rates could not be calculated for an additional nine services. The missing data entry rate was 0.5-22.2%. The overall reported ETI success rate was 86.8% (92.8% for cardiac arrests and 76.8% for non-arrests) and did not appear to vary between population settings. There were two cases of delayed recognition of esophageal intubation, one case of unrecognized esophageal intubation, and 22 cases of tube dislodgement during patient care or transport. Bag-valve-mask ventilation was used as the rescue airway technique in the majority of failed ETI. When stratified for cardiac arrests vs. non-arrests, ETI success was not associated with field or initial ED survival. CONCLUSIONS: We successfully obtained complete data for the majority of ETI attempted across multiple EMS services. Our data also indicate the need to address problems with non-response. Preliminary cross-sectional data highlight areas of current interest in out-of-hospital airway management.
Emergency Medical Services↗