Henry E. Wang

Interruptions in Cardiopulmonary Resuscitation From Paramedic Endotracheal Intubation

STUDY OBJECTIVE Emergency cardiac care guidelines emphasize treatment of cardiopulmonary arrest with continuous uninterrupted cardiopulmonary resuscitation (CPR) chest compressions. Paramedics in the United States perform endotracheal intubation on nearly all victims of out-of-hospital cardiopulmonary arrest. We quantified the frequency and duration of CPR chest compression interruptions associated with paramedic endotracheal intubation efforts during out-of-hospital cardiopulmonary arrest. METHODS We studied adult out-of-hospital cardiopulmonary arrest treated by an urban and a rural emergency medical services agency from the Resuscitation Outcomes Consortium during November 2006 to June 2007. Cardiac monitors with compression sensors continuously recorded rescuer CPR chest compressions. A digital audio channel recorded all resuscitation events. We identified CPR interruptions related to endotracheal intubation efforts, including airway suctioning, laryngoscopy, endotracheal tube placement, confirmation and adjustment, securing the tube in place, bag-valve-mask ventilation between intubation attempts, and alternate airway insertion. We identified the number and duration of CPR interruptions associated with endotracheal intubation efforts. RESULTS We included 100 of 182 out-of-hospital cardiopulmonary arrests in the analysis. The median number of endotracheal intubation-associated CPR interruption was 2 (interquartile range [IQR] 1 to 3; range 1 to 9). The median duration of the first endotracheal intubation-associated CPR interruption was 46.5 seconds (IQR 23.5 to 73 seconds; range 7 to 221 seconds); almost one third exceeded 1 minute. The median total duration of all endotracheal intubation-associated CPR interruptions was 109.5 seconds (IQR 54 to 198 seconds; range 13 to 446 seconds); one fourth exceeded 3 minutes. Endotracheal intubation-associated CPR pauses composed approximately 22.8% (IQR 12.6-36.5%; range 1.0% to 93.4%) of all CPR interruptions. CONCLUSION In this series, paramedic out-of-hospital endotracheal intubation efforts were associated with multiple and prolonged CPR interruptions.

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 &khgr;2 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.

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.

Outcomes after out-of-hospital endotracheal intubation errors ,

INTRODUCTION We sought to evaluate the association between three key out-of-hospital endotracheal intubation (ETI) errors and patient outcomes. METHODS We prospectively collected multicenter data on out-of-hospital ETI attempted by Emergency Medical Service (EMS) rescuers. We probabilistically linked these data to statewide EMS, death and hospital discharge data sets. The key ETI error events were (1) endotracheal tube misplacement or dislodgement, (2) multiple ETI attempts (> or =4 laryngoscopies) and (3) failed ETI. The primary outcomes were death (survival to hospital discharge) and secondary complications identified through ICD-9 discharge diagnoses. Using Cox regression with heavyside functions, we identified the associations between out-of-hospital ETI errors and early (in the field or emergency department) and later (on or after hospital admission) death. We censored non-linked cases, adjusted for important clinical covariates, and used a shared frailty regression model to account for clustering by EMS agency. We evaluated the associations between out-of-hospital ETI errors and secondary complications using univariable odds ratios with exact 95% confidence intervals. RESULTS Of 1954 out-of-hospital ETI, 444 (22.7%) patients experienced one or more ETI errors, including tube misplacement or dislodgement in 61 (3%), multiple ETI attempts in 62 (3%) and failed ETI in 359 (15%). Of the 1196 (61%) cases linked to outcomes, 872 (73%) died and 323 (27%) survived to hospital discharge. ETI errors were not associated with early death (tube misplacement or dislodgement: Hazard Ratio 0.98, 95% CI 0.65-1.47; multiple ETI attempts: 1.22, 0.80-1.85; failed ETI: 1.10, 0.88-1.39) or later death (tube misplacement or dislodgement: 0.40, 0.10-1.62; multiple ETI attempts: 1.77, 0.23-13.30; failed ETI: 0.76, 0.47-1.25). Pneumonitis was associated with failed ETI (n=20, 19%; univariable OR 2.54; 95% CI 1.24-5.25). CONCLUSION Out-of-hospital ETI errors are not associated with mortality. Failed out-of-hospital ETI increases the odds of pneumonitis.

Paramedic Rapid Sequence Intubation for Severe Traumatic Brain Injury: Perspectives from an Expert Panel

Although early intubation has become standard practice in the prehospital management of severe traumatic brain injury (TBI), many patients cannot be intubated without neuromuscular blockade. Several emergency medical services (EMS) systems have implemented paramedic rapid sequence intubation (RSI) protocols, with published reports documenting apparently conflicting outcomes effects. In response, the Brain Trauma Foundation assembled a panel of experts to interpret the existing literature regarding paramedic RSI for severe TBI andoffer guidance for EMS systems considering adding this skill to the paramedic scope of practice. The interpretation of this panel can be summarized as follows: (1) the existing literature regarding paramedic RSI is inconclusive, andapparent differences in outcome can be explained by use of different methodologies andvariability in comparison groups; (2) the use of Glasgow Coma Scale score alone to identify TBI patients requiring RSI is limited, with additional research needed to refine our screening criteria; (3) suboptimal RSI technique as well as subsequent hyperventilation may account for some of the mortality increase reported with the procedure; (4) initial andongoing training as well as experience with RSI appear to affect performance; and(5) the success of a paramedic RSI program is dependent on particular EMS andtrauma system characteristics.

Patient status and time to intubation in the assessment of prehospital intubation performance

Assessment of paramedic endotracheal intubation (ETI) performance often does not account for varied clinical conditions or the time required to complete the procedure. Objective. To demonstrate the utility of patient status and time to intubation (TTI) for evaluating prehospital ETI performance. Methods. Paramedic charts were reviewed for the period January-December 1998. Patient clinical status was defined as cardiac arrest (absence of perfusing rhythm) or non-cardiac arrest (presence of perfusing rhythm). Method, route, and success of ETI were noted. The TTI was determined as the elapsed time from on-scene arrival to securing of the endotracheal tube. Time elapsed from on-scene arrival to emergency department arrival was noted for instances of failed ETI. Statistical analysis was performed using chi-square and survival analysis (Kaplan-Meier estimator). Results. Computer records were available for 26,026 patient contacts. Of 893 documented ETI attempts, 771 (86%) were successful. The ETI success rate was significantly higher (p < 0.001) for cardiac arrests (551 of 591, 93.2%) than for non-cardiac arrests (220 of 302, 72.9%). Median TTIs were 5 minutes (95% CI: 5, 5) for cardiac arrests and 17 minutes (95% CI: 14, 20) for non-cardiac arrests; this difference was significant (p < 0.001). For non-cardiac arrests, ETI success was significantly (p = 0.002) higher for orotracheal intubation (OTI) (168 of 214, 78.5%) than for nasotracheal intubation (NTI) (52 of 88, 59.1%). Median TTIs were 15 minutes (95% CI: 13, 17) for OTI and 25 minutes (95% CI: 23, 27) for NTI; this difference was significant (p = 0.002). For non-cardiac arrests, the difference in ETI success rates between conventional ETI (63 of 88, 71.6%) and midazolam-facilitated ETI (157 of 214, 73.4%) was not significant (p = 0.75). Median TTIs were 16 minutes (95% CI: 13, 19) for conventional ETI and 19 minutes (95% CI: 16, 22) for the midazolam-facilitated ETI; this difference was not significant (p = 0.08). Conclusions. The TTI is shorter and ETI success rates are higher for patients in cardiac arrest. Similar trends are observed for OTI compared with NTI in non-cardiac arrest patients. Success rates and TTIs for conventional vs midazolam-facilitated intubation in non-cardiac arrest patients do not differ. Prehospital ETI data should be segregated according to patient clinical status. Survival analysis of TTI can be used to establish time benchmarks for performing field intubation and to define strategies for approaching field intubation.

Emergency department visits by nursing home residents in the United States.

To characterize emergency department (ED) use by nursing home residents in the United States.

The utilization of midazolam as a pharmacologic adjunct to endotracheal intubation by paramedics

Objective. Pharmacologic agents have been used in the prehospital setting for facilitating endotracheal intubation (ETI). The purpose of this study was to determine the utility of intravenous midazolam for prehospital patients who require pharmacologic relaxation to facilitate ETI. Methods. Data were reviewed retrospectively using paramedic charts from an eight-month period for a three-county state EMS system. Results. There were 26,133 paramedic dispatches during the study period. Six hundred eighty-three ETIs were attempted, including 72 midazolam-facilitated intubations (MFIs). The most common indications for MFI were “clenched teeth,” “gag,” and “combativeness.” Successful MFI was achieved in 45 of 72 cases (62.5%). Midazolam-facilitated intubation was less successful for trauma patients (41.2%) than for medical patients (69.1%) (p = 0.04). Of the 58 failed conventional ETIs that occurred during the study period, 25 (43.1%) were identified as having one or more indications for the use of MFI. Although the use of intravenous midazolam was effective in facilitating ETI, a high MFI failure rate (37.5%) was noted. Conclusion. Although it is of limited efficacy, MFI is underutilized and should be considered by medical direction as a pharmacologic adjunct to ETI in selected field patients.

I NTRAOSSEOUS I NFUSION

Establishing vascular access is vital in the resuscitation of critically-ill children and adults. Intraosseous infusion (IOI) is a viable route for providing vascular access when traditional intravenous methods cannot be accomplished. IOI is relatively easy to perform and is a standard recommended intervention for the resuscitation of both adults and children. The authors review the history, anatomy, technique, and clinical application of IOI. They also highlight the use of IOI in the prehospital setting.

FEASIBILITY OF STERNAL INTRAOSSEOUS ACCESS BY EMERGENCY MEDICAL TECHNICIAN STUDENTS

Objective. Emergency medical technician–basic (EMT-B) providers are not trained to establish vascular or intraosseous (IO) access on critically ill patients. This study was conducted to examine the feasibility of training EMT-B students to correctly place a commercial sternal IO infusion device (FAST-1). Methods. Twenty-nine EMT-B students attended a two-hour training session. Subjects were subsequently tested in FAST-1 application using a modified resuscitation mannequin permitting IO needle deployment. Two observers assessed correct IO application andtechnique. Results were analyzed using descriptive statistics (binomial proportions andmedians with 95% confidence intervals). Inter-rater agreement of observations was evaluated using kappa statistics andintraclass correlation coefficients (ICCs). Results. Inter-rater agreement ranged from fair to excellent (kappa = 0.37–1.00) for all parameters except sternal notch identification (kappa = −0.03). Reliabilities of elapsed times were good (ICC = 0.83, 0.31). Correct identification of the sternal notch was accomplished by 28 of 29 students (96.6%; 95% CI: 82.2–99.9%). Correct application of the IO target patch was achieved by 29 of 29 (100.0%; 88.1–100.0%). First-attempt successful IO needle deployment was achieved by 16 of 29 (55.2%; 35.7–73.6%). Overall successful IO needle deployment within four attempts was achieved by 27 of 29 (93.1%; 77.2–99.2%). The protective dome was correctly applied by 27 of 29 (93.1%; 77.2–99.2%). The median time to needle deployment was 27.5 seconds (95% CI: 24–31). The median time to dome placement was 50 seconds (95% CI: 42–55). Conclusions. EMT-B students with minimal training demonstrated limited success with applying a commercial sternal IO device. Clinical application by EMT-Bs on critically ill patients may be possible with more intensive training.