Michael W. Hubble

A meta-analysis of prehospital airway control techniques part I: orotracheal and nasotracheal intubation success rates.

Abstract Background. Airway management is a key component of prehospital care for seriously ill and injured patients. Although endotracheal intubation has been a commonly performed prehospital procedure for nearly three decades, the safety and efficacy profile of prehospital intubation has been challenged in the last decade. Reported intubation success rates vary widely, and established benchmarks are lacking. Objective. We sought to determine pooled estimates for oral endotracheal intubation (OETI) and nasotracheal intubation (NTI) placement success rates through a meta-analysis of the literature. Methods. We performed a systematic literature search for all English-language articles reporting placement success rates for prehospital intubation. Studies of field procedures performed by prehospital personnel from any nation were included. All titles were reviewed independently by two authors using prespecified inclusion criteria. Pooled estimates of success rates for each airway technique, including drug-facilitated intubation (DFI) and rapid-sequence intubation (RSI), were calculated using a random-effects model. Historical trends were evaluated using meta-regression. Results. Of 2,005 identified titles reviewed, 117 studies addressed OETI and 23 addressed NTI, encompassing a total of 57,132 prehospital patients. There was substantial interrater reliability in the review process (kappa = 0.81). The pooled estimates (and 95% confidence intervals [CIs]) for intervention success for nonphysician clinicians were as follows: overall non-RSI/non-DFI OETI success rate: 86.3% (82.6%–89.4%); OETI for non–cardiac arrest patients: 69.8% (50.9%–83.8%); DFI 86.8% (80.2%–91.4%); and RSI 96.7% (94.7%–98.0%). For pediatric patients, the paramedic OETI success rate was 83.2% (55.2%–95.2%). The overall NTI success rate for nonphysician clinicians was 75.9% (65.9%–83.7%). The historical trend of OETI reflects a 0.49% decline in success rates per year. Conclusions. We provide pooled estimates of placement success rates for prehospital airway interventions. For some patient and clinician characteristics, OETI has relatively low success rates. For nonarrest patients, DFI and RSI appear to increase success rates. Across all clinicians, NTI has a low rate of success, raising questions about the safety and efficacy of this procedure.

A meta-analysis of prehospital airway control techniques. Part II: Alternative airway devices and cricothyrotomy success rates

Abstract Background. Airway management is a key component of prehospital care for seriously ill and injured patients. Oral endotracheal intubation (OETI) is the definitive airway of choice in most emergency medical services (EMS) systems. However, OETI may not be an approved skill for some clinicians or may prove problematic in certain patients because of anatomic abnormalities, trauma, or inadequate relaxation. In these situations alternative airways are frequently employed. However, the reported success rates for these devices vary widely, and established benchmarks are lacking. Objective. We sought to determine pooled estimates of the success rates of alternative airway devices (AADs) and needle cricothyrotomy (NCRIC) and surgical cricothyrotomy (SCRIC) placement through a meta-analysis of the literature. Methods. We performed a systematic literature search for all English-language articles reporting success rates for AADs, SCRIC, and NCRIC. Studies of field procedures performed by prehospital personnel from any nation were included. All titles were reviewed independently by two authors using prespecified inclusion criteria. Pooled estimates of success rates for each airway technique were calculated using a random-effects meta-analysis model. Results. Of 2,005 prehospital airway titles identified, 35 unique studies were retained for analysis of AAD success rates, encompassing a total of 10,172 prehospital patients. The success rates for SCRIC and NCRIC were analyzed across an additional 21 studies totaling 512 patients. The pooled estimates (and 95% confidence intervals [CIs]) for intervention success across all clinicians and patients were as follows: esophageal obturator airway–esophageal gastric tube airway (EOA-EGTA) 92.6% (90.1%–94.5%); pharyngeotracheal lumen airway (PTLA) 82.1% (74.0%–88.0%); esophageal-tracheal Combitube (ETC) 85.4% (77.3%–91.0%); laryngeal mask airway (LMA) 87.4% (79.0%–92.8%); King Laryngeal Tube airway (King LT) 96.5% (71.2%–99.7%); NCRIC 65.8% (42.3%–83.59%); and SCRIC 90.5% (84.8%–94.2%). Conclusions. We provide pooled estimates for prehospital AAD, NCRIC, and SCRIC airway interventions. Of the AADs, the King LT demonstrated the highest insertion success rate (96.5%), although this estimate is based on limited data, and data regarding its ventilatory effectiveness are lacking; more data are available for the ETC and LMA. The ETC, LMA, and PTLA all had similar—but lower—success rates (82.1%–87.4%). NCRIC has a low rate of success (65.8%); SCRIC has a much higher success rate (90.5%) and should be considered the preferred percutaneous rescue airway.

Association Between Poor Sleep, Fatigue, and Safety Outcomes in Emergency Medical Services Providers

Abstract Objective. To determine the association between poor sleep quality, fatigue, and self-reported safety outcomes among emergency medical services (EMS) workers. Methods. We used convenience sampling of EMS agencies and a cross-sectional survey design. We administered the 19-item Pittsburgh Sleep Quality Index (PSQI), 11-item Chalder Fatigue Questionnaire (CFQ), and 44-item EMS Safety Inventory (EMS-SI) to measure sleep quality, fatigue, and safety outcomes, respectively. We used a consensus process to develop the EMS-SI, which was designed to capture three composite measurements of EMS worker injury, medical errors and adverse events (AEs), and safety-compromising behaviors. We used hierarchical logistic regression to test the association between poor sleep quality, fatigue, and three composite measures of EMS worker safety outcomes. Results. We received 547 surveys from 30 EMS agencies (a 35.6% mean agency response rate). The mean PSQI score exceeded the benchmark for poor sleep (6.9, 95% confidence interval [CI] 6.6, 7.2). More than half of the respondents were classified as fatigued (55%, 95% CI 50.7, 59.3). Eighteen percent of the respondents reported an injury (17.8%, 95% CI 13.5, 22.1), 41% reported a medical error or AE (41.1%, 95% CI 36.8, 45.4), and 90% reported a safety-compromising behavior (89.6%, 95% CI 87, 92). After controlling for confounding, we identified 1.9 greater odds of injury (95% CI 1.1, 3.3), 2.2 greater odds of medical error or AE (95% CI 1.4, 3.3), and 3.6 greater odds of safety-compromising behavior (95% CI 1.5, 8.3) among fatigued respondents versus nonfatigued respondents. Conclusions. In this sample of EMS workers, poor sleep quality and fatigue are common. We provide preliminary evidence of an association between sleep quality, fatigue, and safety outcomes.

Effectiveness of Prehospital Continuous Positive Airway Pressure in the Management of Acute Pulmonary Edema

Objective. To compare the effectiveness of continuous positive airway pressure (CPAP) with standard pharmacologic treatment in the management of prehospital acute pulmonary edema. Methods. Using a nonrandomized control group design, all consecutive patients presenting to two participating emergency medical services (EMS) systems with a field impression of acute pulmonary edema between July 1, 2004, andJune 30, 2005, were included in the study. The control EMS system patients received standard treatment with oxygen, nitrates, furosemide, morphine, and, if indicated, endotracheal intubation. The intervention EMS system patients received CPAP via face mask at 10 cm H2O in addition to standard therapy. Results. Ninety-five patients received standard therapy, and120 patients received CPAP andstandard therapy. Intubation was required in 8.9% of CPAP-treated patients compared with 25.3% in the control group (p = 0.003), andmortality was lower in the CPAP group than in the control group (5.4% vs. 23.2%; p = 0.000). When compared with the control group, the CPAP group had more improvement in respiratory rate (−4.55 vs. −1.81; p = 0.001), pulse rate (−4.77 vs. 0.82; p = 0.013), anddyspnea score (−2.11 vs. −1.36; p = 0.008). Using logistic regression to control for potential confounders, patients receiving standard treatment were more likely to be intubated (odds ratio, 4.04; 95% confidence interval, 1.64 to 9.95) andmore likely to die (odds ratio, 7.48; 95% confidence interval, 1.96 to 28.54) than those receiving standard therapy andCPAP. Conclusion. The prehospital use of CPAP is feasible, may avert the need for endotracheal intubation, andmay reduce short-term mortality.

W ILLINGNESS OF H IGH S CHOOL S TUDENTS TO P ERFORM C ARDIOPULMONARY R ESUSCITATION AND A UTOMATED E XTERNAL D EFIBRILLATION

Objective. To evaluate the willingness of high school students to perform cardiopulmonary resuscitation (CPR) and automated external defibrillation (AED). Methods. A convenience sample of high school students was surveyed regarding how they would respond if they witnessed a cardiac arrest. Participants were first shown a video segment on the operation of an automated external defibrillator. They were then shown a series of video clips depicting six different cardiac arrest scenarios: motor vehicle collision (MVC) with facial bleeding, pediatric drowning, intravenous (IV) drug user, choking family member, victim of differing race, and victim with facial vomitus. Following each video, the subjects were asked how they would respond had they actually witnessed a similar event. Results. With parental permission and institutional review board approval, 683 students participated, representing 6.8% of the total student body. Of these, 585 (86%) were trained in CPR and 142 (21%) in AED. One hundred six participants (16%) had witnessed a cardiac arrest prior to the survey. Of these, 24 (23%) had intervened in some way. Twenty (19%) had performed mouth-to-mouth resuscitation (MMR), 15 (14%) had performed chest compressions (CC), and one (0.9%) had performed AED. Across all six mock scenarios and all 683 respondents collectively (4,098 simulated cardiac arrest events), the respondents indicated they would be willing to perform AED 1,308 times (32%). In comparison, the respondents indicated they would be willing to perform MMR 1,768 times (43%) and CC 2,249 times (55%). More respondents were willing to intervene on behalf of a child or family member, while fewer were willing to act in the setting of blood, vomitus, or an IV drug user (p < 0.05). There was no association between willingness to intervene and prior experience with any of the interventions. Fear of infection, legal consequences, and fear of harming the patient were the most frequently cited reasons for not intervening. Conclusions. Among high school students, few are willing to perform automated external defibrillation. Willingness to perform MMR and CC appears to depend on the circumstances.

Medication calculation skills of practicing paramedics

Objective. To assess the medication calculation skills among a group of practicing paramedics, the types of computations they find most difficult, and the relationship between drug calculation skills and various demographic characteristics. Methods. A demographic survey and a ten-item drug calculation examination were administered to a convenience sample of 109 practicing paramedics representing a cross-section of emergency medical services (EMS) system characteristics in North Carolina. Examinations were scored independently by two graders and error types were assigned to incorrect responses. Examination results were then correlated with demographic and EMS system characteristics. Results. Overall performance on the drug calculation examination was poor. The mean score was 51.4% (SD 27.4). Intravenous flow rate problems and medication bolus problems were calculated correctly in 68.8% of the cases, followed by non-weight-based medication infusions (33.9%), weight-based medication infusions (32.5%), and percentage-based medication infusions (4.5%). Examination scores were higher among paramedics with college level education, but scores were lower among paramedics with more years of EMS experience. Conceptual errors (i.e., errors in setting up the problem) were more prevalent than mathematical errors, errors in weight conversion, or errors in unit conversion (e.g., grams to milligrams). The participants reported that drug calculations were infrequently performed in daily practice and were rarely a topic of continuing education programs. Conclusion. Similar to findings among other allied health professions, medication calculation skills were found to be lacking among a group of practicing paramedics. In addition, the paramedics reported infrequent opportunities to perform this skill in the clinical setting and that medication calculations were not a routine part of EMS continuing education programs.

Training prehospital personnel in saphenous vein cutdown and adult intraosseous access techniques

Objective. To compare the success rates, complication rates, and times required for paramedic students to perform saphenous vein cutdown and adult intraosseous infusion using the bone injection gun (BIG). Methods. This was a prospective, randomized crossover study of 13 senior-level students in a baccalaureate degree paramedic program. Study subjects were instructed in adult intraosseous and saphenous vein cutdown techniques through lecture and laboratory exercises and then randomized into two groups. Group 1 performed saphenous vein cutdown at the ankle, followed by intraosseous infusion using the BIG. Group 2 performed the same procedures but in reverse order. All procedures were performed on preserved cadavers and videotaped. Using a standardized scoring sheet, the authors evaluated the study subjects at the time of the procedures to determine success rates, errors, and complications. Videotapes were later reviewed to verify the time required to complete the procedures. Results. The normalized mean procedure scores were 96.15 (SD 4.28) and 83.83 (SD 15.52) for the intraosseous infusion and saphenous vein cutdown procedures, respectively (95% CI for difference in means, −12.34 to −1.3; p = 0.020). Success rates for establishing venous access were higher for the intraosseous route (92.3%) than the cutdown technique (69.2%), but did not achieve statistical significance (p = 0.250). The times required to initiate fluid flow were 3.91 minutes (SD 0.82) by the intraosseous route and 7.57 minutes (SD 1.80) by venous cutdown (95% CI for difference in means, 2.43 to 5.55; p = 0.000). One critical error and 11 noncritical errors were encountered during the intraosseous procedure, compared with ten critical errors and 29 noncritical errors during the cutdown procedure ( p = 0.195). Conclusion. In a group of inexperienced paramedic students working on a preserved human cadaver model, intravenous access was gained more rapidly, with a higher success rate, and with fewer complications using the bone injection gun than by the saphenous vein cutdown procedure. Further study is needed to evaluate these procedures in the field setting and to compare their feasibility with other alternative venous access techniques such as femoral, external jugular, and central venous cannulation.

Time to First Compression Using Medical Priority Dispatch System Compression-First Dispatcher-Assisted Cardiopulmonary Resuscitation Protocols

Abstract Introduction. Without bystander cardiopulmonary resuscitation (CPR), cardiac arrest survival decreases 7%–10% for every minute of delay until defibrillation. Dispatcher-assisted CPR (D-CPR) has been shown to increase the rates of bystander CPR and cardiac arrest survival. Other reports suggest that the most critical component of bystander CPR is chest compressions with minimal interruption. Beginning with version 11.2 of the Medical Priority Dispatch System (MPDS) protocols, instructions for mouth-to-mouth ventilation (MTMV) and pulse check were removed and a compression-first pathway was introduced to facilitate rapid delivery of compressions. Additionally, unconscious choking and third-trimester pregnancy decision-making criteria were added in versions 11.3 and 12.0, respectively. However, the effects of these changes on time to first compression (TTFC) have not been evaluated. Objective. We sought to quantify the TTFC of MPDS versions 11.2, 11.3, and 12.0 for all calls identified as cardiac arrest on call intake that did not require MTMV instruction. Methods. Audio recordings of all D-CPR events for October 2005 through May 2010 were analyzed for TTFC. Differences in TTFC across versions were compared using the Kruskal-Wallis test. Results. A total of 778 cases received D-CPR. Of these, 259 were excluded because they met criteria for MTMV (pediatric patients, allergic reaction, etc.), were missing data, or were not initially identified as cardiac arrest. Of the remaining 519 calls, the mean TTFC was 240 seconds, with no significant variation across the MPDS versions (p = 0.08). Conclusions. Following the removal of instructions for pulse check and MTMV, as well as other minor changes in the MPDS protocols, we found the overall TTFC to be 240 seconds with little variation across the three versions evaluated. This represents an improvement in TTFC compared with reports of an earlier version of MPDS that included pulse checks and MTMV instructions (315 seconds). However, the MPDS TTFC does not compare favorably with reports of older, non-MPDS protocols that included pulse checks and MTMV. Efforts should continue to focus on improving this key, and modifiable, determinant of cardiac arrest survival. Key words: emergency medical dispatch; emergency medical services; prehospital; paramedic; cardiac arrest; CPR

Estimates of Cost-Effectiveness of Prehospital Continuous Positive Airway Pressure in the Management of Acute Pulmonary Edema

Objective. To estimate the cost-effectiveness of continuous positive airway pressure (CPAP) in managing prehospital acute pulmonary edema in an urban EMS system. Methods. Using estimates from published reports on prehospital andemergency department CPAP, a cost-effectiveness model of implementing CPAP in a typical urban EMS system was derived from the societal perspective as well as the perspective of the implementing EMS system. To assess the robustness of the model, a series of univariate andmultivariate sensitivity analyses was performed on the input variables. Results. The cost of consumables, equipment, andtraining yielded a total cost of

The longitudinal study of turnover and the cost of turnover in emergency medical services.

89 per CPAP application. The theoretical system would be expected to use CPAP 4 times per 1000 EMS patients andis expected to save 0.75 additional lives per 1000 EMS patients at a cost of