CJEM Articles: P. Richard Verbeek

Objective: We sought to determine whether the use of currently issued gowns delays initiation of chest compressions and ventilations during cardiopulmonary resuscitation and whether simple gown modifications can reduce this delay.

Methods: Firefighter defibrillation instructors were allocated into pairs and videotaped while performing standardized cardiac arrest scenarios. Three scenarios were compared: "no gown," "standard gown" and "modified gown." Key time intervals were extracted from videotaped data.

Results: Ninety-five scenarios were analyzed. Mean time interval to chest compression was 39 seconds (95% confidence interval [CI] 34-43) for "no gown" scenarios, 71 seconds (95% CI 66-77) for "standard gown" scenarios and 59 seconds (95% CI 54-63) for "modified gown" scenarios (p < 0.001). Time to first ventilation was 146 seconds (95% CI 134-158), 238 seconds (95% CI 224-253) and 210 seconds (95% CI 198-223) in the 3 groups, respectively (p < 0.001). Post hoc testing showed that the time differences between all groups were statistically significant.

Conclusion: Standard gowns protect front-line care providers but cause significant delays to chest compressions and ventilations, potentially increasing patient morbidity and mortality. Minor gown modifications, including pre-tied neck straps and longer waist ties that tie in front, allow for easier use and shorter delays to time-critical interventions. Future research is required to reduce care delays while maintaining adequate protection of emergency medical service providers from infectious disease.

Objectives: National survival rates for out-of-hospital cardiac arrests are less than 5%, and substantial resources are associated with transporting cardiac arrest victims to hospital for emergency department (ED) resuscitation. The low overall survival rate and the identification of predictors of unsuccessful resuscitation have opened debate on the "futility" of transporting such patients to the ED. This study compares the costs of prehospital pronouncement of death to the costs of transporting patients to a hospital ED for physician pronouncement.
Methods: The study was a retrospective chart review on a matched cohort of out-of-hospital cardiac arrest patients. Patients were included if documentation was adequate and ambulance response time was less than 8 minutes. A cohort of 20 patients pronounced dead in the field were matched to 20 patients pronounced dead in an ED. Cases were matched on 6 evidence-based predictors of unsuccessful resuscitation. Direct medical costs and mean physician and prehospital provider times were compared.
Results: The total cost of pronouncement of death in the ED was $45.35 higher than the cost of field pronouncement (p < 0.001). Paramedics spent more time delivering care when death was pronounced in the field (83.3 vs. 55.9 min; p < 0.001). Base hospital physicians spent more time when patients were transported to hospital for ED pronouncement (16.3 vs. 4.3 min; p < 0.001). Total provider time for field pronouncement was 15.5 min longer (p = 0.004), but field pronouncement consumed 12.0 min less physician time.
Conclusions: Paramedic pronouncement of death in the field is less costly than transporting patients to hospital for physician pronouncement. Pronouncement in the field requires more paramedic time but less physician time.

Objectives: Our goals were to determine whether selection bias occurred in a prehospital study comparing an esophageal detector device (EDD) to a disposable capnometer for detecting esophageal intubation, and to determine whether such a bias would have changed the study’s conclusions about EDD effectiveness.
Methods: In a study of patients requiring prehospital intubation, we determined the sensitivity, specificity and predictive values of the EDD for detecting esophageal intubation. We then compared intubation success rate in patients who were enrolled in the study (n = 129) to that in eligible patients who were excluded from it (n = 107). After finding that the incidence of failed intubation was higher in the “excluded” group, we used sensitivity and specificity parameters derived from the study population to assess whether EDD test characteristics would differ in studied vs. excluded patients.
Results: The first intubation attempt was successful in 125 of 129 study patients and 76 of 107 excluded patients (97% vs. 71%, p = 0.03), confirming the presence of selection bias. The negative predictive value of the EDD for esophageal intubation was 98% in the study cohort and would have been 77% in patients like those excluded (i.e., difficult intubation cases).
Conclusion: The high “first attempt” intubation success rate seen in this study was due to selective exclusion of failed intubations. This selection bias led to a clinically important overestimation of the EDD’s negative predictive value. Bias may substantially alter the estimations of test accuracy reported in scientific studies. To reduce the chance of unrecognized selection bias in studies of diagnostic tests, investigators must determine whether recruited subjects resemble patients in whom the test will ultimately be used.