Adam Frisch

Duration of Resuscitation Efforts and Functional Outcome After Out-of-Hospital Cardiac Arrest When Should We Change to Novel Therapies?

Background— Functionally favorable survival remains low after out-of-hospital cardiac arrest. When initial interventions fail to achieve the return of spontaneous circulation, they are repeated with little incremental benefit. Patients without rapid return of spontaneous circulation do not typically survive with good functional outcome. Novel approaches to out-of-hospital cardiac arrest have yielded functionally favorable survival in patients for whom traditional measures had failed, but the optimal transition point from traditional measures to novel therapies is ill defined. Our objective was to estimate the dynamic probability of survival and functional recovery as a function of resuscitation effort duration to identify this transition point. Methods and Results— Retrospective cohort study of a cardiac arrest database at a single site. We included 1014 adult (≥18 years) patients experiencing nontraumatic out-of-hospital cardiac arrest between 2005 and 2011, defined as receiving cardiopulmonary resuscitation or defibrillation from a professional provider. We stratified by functional outcome at hospital discharge (modified Rankin scale). Survival to hospital discharge was 11%, but only 6% had a modified Rankin scale of 0 to 3. Within 16.1 minutes of cardiopulmonary resuscitation, 89.7% (95% confidence interval, 80.3%–95.8%) of patients with good functional outcome had achieved return of spontaneous circulation, and the probability of good functional recovery fell to 1%. Adjusting for prehospital and inpatient covariates, cardiopulmonary resuscitation duration (minutes) is independently associated with favorable functional status at hospital discharge (odds ratio, 0.84; 95% confidence interval, 0.72–0.98; P=0.02). Conclusions— The probability of survival to hospital discharge with a modified Rankin scale of 0 to 3 declines rapidly with each minute of cardiopulmonary resuscitation. Novel strategies should be tested early after cardiac arrest rather than after the complete failure of traditional measures.

Prediction of Serious Infection During Prehospital Emergency Care

Abstract Background. Regionalization of emergency care for patients with serious infections has the potential to improve outcomes, but is not feasible without accurate identification of patients in the prehospital environment. Objective. To determine the incremental predictive value of provider judgment in addition to prehospital physiologic variables for identifying patients who have serious infections. Methods. We conducted a prospective study at a single teaching tertiary-care emergency department (ED) where a convenience sample of emergency medical services (EMS) providers and ED clinicians completed a questionnaire about the same patients. Prehospital providers provided limited demographics and work history about themselves. They also reported the presence of abnormal prehospital physiology for each patient (heart rate >90 beats/min, systolic blood pressure <100 mmHg, respiratory rate >20 breaths/min, pulse oximetry <95%, history of fever, altered mental status) and their judgment about whether the patient had an infection. At the end of formal evaluation in the ED, the physician was asked to complete a survey describing the same patient factors in addition to patient disposition. The primary outcome of serious infection was defined as the presence of both 1) ED report of acute infection and 2) patient admission. We included prehospital factors associated with serious infection in the prediction models. Operating characteristics for various cutoffs and the area under the curve (AUC) were calculated and reported with 95% confidence intervals (95% CIs). Results. Serious infection occurred in 32 (16%) of 199 patients transported by EMS, 50% of whom were septic, and 16% of whom were admitted to the intensive care unit. Prehospital systolic blood pressure <100 mmHg, EMS-elicited history or suspicion of fever, and prehospital judgment of infection were associated with primary outcome. Presence of any one of these resulted in a sensitivity of 0.59 (95% CI 0.40–0.76) and a specificity of 0.81 (95% CI 0.74–0.86). The AUC for the model was 0.71. Conclusions. Including prehospital provider impression to objective physiologic factors identified three more patients with infection at the cost of overtriaging five. Future research should determine the effect of training or diagnostic aids for improving the sensitivity of prehospital identification of patients with serious infection.

Documentation discrepancies of time-dependent critical events in out of hospital cardiac arrest

OBJECTIVES The timing of and interval between events in prehospital care is important for system design, patient outcome, and prehospital research. Since these data can guide treatment recommendations, it is imperative that time-based prehospital documentation is accurate and precise, especially for time-sensitive conditions such as out-of-hospital cardiac arrest (OHCA). We compared the times of select events documented in the medical record (PCR) with times from time-stamped audio recordings in the monitor-defibrillator (AUD). METHODS A retrospective cohort of prehospital, adult, atraumatic OHCA resuscitations from two regional EMS agencies over a 10-month period was performed. Primary outcome was absolute difference (minutes) between PCR and AUD documented times for select events during OHCA resuscitation (IV access, IO access, first epinephrine administration, supraglottic airway insertion, endotracheal intubation, and return of spontaneous circulation). We describe the magnitude and direction of differences, and estimate the potential error in time intervals abstracted from the medical record. RESULTS Of 411 patients treated by EMS, 192 had complete data for ≥1 event and 136 had complete data for ≥2 events. 422 total events were identifiable in both PCR and AUD. Median absolute time discrepancy between PCR and AUD was 2 (IQR 1-4) min. Median differences between the smallest and largest PCR-AUD discrepancy was 2 (IQR 1-4.5) min. Discrepancies were both positive and negative, and not consistent within individual records. CONCLUSION We found a 2 (IQR 1-4) min imprecision in the documented timing of select events during OHCA resuscitation. This imprecision contributes to uncertainty in analyses that incorporate time-stamped variables.

Potential Utility of Near-Infrared Spectroscopy in Out-of-Hospital Cardiac Arrest: An Illustrative Case Series

Abstract Objective. We evaluated the measurement of tissue oxygen content (StO2) by continuous near-infrared spectroscopy (NIRS) during and following cardiopulmonary rescuscitation (CPR) and compared the changes in StO2 and end-tidal carbon dioxide (ETCO2) as a measure of return of spontaneous circulation (ROSC) or rearrest. Methods. This was a case series of five patients who experienced out-of hospital cardiac arrest. Patients included those who had already experienced ROSC, who were being transported to the hospital, or who were likely to have a reasonable amount of time remaining in the resuscitation efforts. Patients were continuously monitored from the scene using continuous ETCO2 monitoring and a NIRS StO2 monitor until they reached the hospital. The ETCO2 and StO2 values were continuously recorded and analyzed for comparison of the time points when patients were clinically identified to have ROSC or rearrest. Results. Four of five patients had StO2 and EtCO2 recorded during an episode of CPR and all were monitored during the postarrest period. Three patients experienced rearrest en route to the hospital. Downward trends were noted in StO2 prior to each rearrest, and rapid increases were noted after ROSC. The StO2 data showed less variance than the ETCO2 data in the periarrest period. Conclusions. This preliminary study in humans demonstrates that StO2 dynamically changes during periods of hemodynamic instability in postarrest patients. These data suggest that a decline in StO2 level may correlate with rearrest and may be useful as a tool to predict rearrest in post–cardiac arrest patients. A rapid increase in StO2 was also seen upon ROSC and may be a better method of identifying ROSC during CPR than pauses for pulse checks or ETCO2 monitoring. Key words: resuscitation; hemodynamics; tissue oxygen content; near-infrared spectroscopy; cardiopulmonary resuscitation; return of spontaneous circulation; rearrest

The Prevalence of Cardiovascular Disease Risk Factors and Obesity in Firefighters

Obesity is associated with increased risk of cardiovascular disease (CVD) mortality. CVD is the leading cause of duty-related death among firefighters, and the prevalence of obesity is a growing concern in the Fire Service. Methods. Traditional CVD risk factors, novel measures of cardiovascular health and a measurement of CVD were described and compared between nonobese and obese career firefighters who volunteered to participate in this cross-sectional study. Results. In the group of 116 men (mean age 43 ± 8 yrs), the prevalence of obesity was 51.7%. There were no differences among traditional CVD risk factors or the coronary artery calcium (CAC) score (criterion measure) between obese and nonobese men. However, significant differences in novel markers, including CRP, subendocardial viability ratio, and the ejection duration index, were detected. Conclusions. No differences in the prevalence of traditional CVD risk factors between obese and nonobese men were found. Additionally, CAC was similar between groups. However, there were differences in several novel risk factors, which warrant further investigation. Improved CVD risk identification among firefighters has important implications for both individual health and public safety.

Tissue oximetry by near-infrared spectroscopy in a porcine model of out-of-hospital cardiac arrest and resuscitation

INTRODUCTION Monitoring during resuscitation remains relatively crude. Near-infrared spectroscopy (NIRS) measures aggregate oxygen saturation in a volume of tissue. We assessed the utility of continuous StO2 measurement in a porcine model of cardiac arrest, and explored the effects of differential vasoconstriction on StO2. We hypothesized that (1) StO2 trends correspond with the onset of loss of pulses, resuscitation, and return of spontaneous circulation (ROSC); (2) epinephrine has a dose-dependent effect on StO2. METHODS We anesthetized and instrumented 7 female swine, placing a NIRS probe on the left forelimb to recorded StO2. After 8 min of untreated VF and 2 min of CPR, we randomized animals to 0.015 mgkg(-1) (SDE) or 0.1mgkg(-1) (HDE) epinephrine. After 3 min of CPR, animals were defibrillated. Animals with ROSC were given SDE, then HDE for subsequent hemodynamic deteriorations. Data were analyzed with descriptive statistics and generalized linear model (alpha=0.05) to determine overall slope of pooled StO2 across animals for resuscitation segments. RESULTS Four animals received HDE and three SDE. All achieved ROSC. Significant coefficients (ΔStO2 min(-1)) were noted for resuscitation segments. StO2 decreased after loss of pulses (-29.1; 95%CI -33.4, -24.7; p<0.01) but plateaued during CPR (-0.2; 95%CI -1.2, 0.8; p=0.71). There was a graded decline in StO2 between SDE (-1.3; 95%CI -1.5, -1.2; p<0.01) and HDE (-3.1; 95%CI -5.8, -0.4; p=0.03). The slowest change occurred with ROSC (0.4; 95%CI 0.3, 0.5; p<0.01). CONCLUSIONS In a porcine model of OHCA, peripheral StO2 rapidly decreased after loss of pulses, but did not improve with CPR or epinephrine. It increased extremely slowly after ROSC.

Prevalence and Interventional Outcomes of Patients with Resolution of ST-segment Elevation between Prehospital and In-hospital ECG

Abstract Objective. To determine the prevalence and significance of ST-segment elevation resolution between prehospital and first hospital ECG. Methods. We examined consecutive prehospital ECGs transmitted to a single medical command center in southwestern Pennsylvania between January 1, 2009 and December 31, 2011. We included ECG cases with ST-segment elevation myocardial infarction (STEMI) and excluded cases with incomplete prehospital and/or hospital data. Our primary outcome was ST-segment resolution (STR), defined by cases no longer meeting STEMI criteria on the first in-hospital ECG. Primary variables of interest included prehospital vital signs and treatment, cardiac catheterization findings, and time intervals for diagnostics and treatment. Analysis included t-tests for continuous variables and chi-squared analysis for categorical variables. Results. We reviewed 24,197 prehospital ECGs and identified 293 cases of prehospital STEMI. Complete hospital and prehospital records were available for 83 cases (28%). Analyzed cohort was an average 62 years old and the majority were male (67%), with a primary complaint of chest pain (93%). STR occurred in 18 cases (22%, CI 14–32%). There were no differences between STR and non-STR cases in prehospital vital signs or treatments. 95% of patients underwent cardiac catheterization with a mean door-to-needle time of 57 minutes (interquartile range 43–71). Comparing STR and non-STR cases, significant lesions (≥50%) were found in 94 and 97% of patients (p = 0.6), and subtotal or total lesions (≥95%) were found in 63 and 85% (p = 0.1), respectively. Conclusions. We found that ST-segment resolution occurred prior to catheterization in 1 of 5 patients with prehospital STEMI, emphasizing the necessity of prehospital ECG in risk stratification of patients with suspected coronary disease. Coronary lesions and intervention rates did not differ between STR and non-STR, suggesting that catheterization is warranted even when STEMI criteria are no longer met in-hospital. Key words: 

Multivariate analysis of successful intravenous line placement in the prehospital setting.

Abstract Background. Intravenous (IV) line placement is an important prehospital advanced life support skill, but IV success rates are variable among providers. Little is known about what factors are associated with successful IV placement, limiting the ability to develop benchmarks for skill maintenance, such as requiring a specific number of IV placements per year. Objective. We aimed to identify whether first-pass IV success was associated with the number of attempted or successful previous IV attempts. We hypothesized that IV success is associated with the number of successful IV placements in the preceding year. Methods. We retrospectively studied 800 consecutive charts with an IV attempt from 11 suburban and rural emergency medical services (EMS) agencies over a one-month period. Cases involving pediatric patients (age <18 years) and those with incomplete data were excluded. Success of the first IV attempt was identified. Potential predictor variables were collected and analyzed by univariate logistic regression, including patient age, systolic blood pressure, history of IV drug abuse or renal disease, traumatic event, catheter size, and location of IV attempt, as well as the individual providers numbers of total and successful IV attempts in the preceding year. Variables significantly associated with IV success at the p < 0.10 level were included in a multivariate regression model using a p-value of 0.05. Results. Of 602 cases meeting the study criteria, 469 (77.9%) had a successful first-pass IV placement. Significantly associated with IV success in the univariate regression were patient age (p = 0.054), trauma (p = 0.074), IV catheter size (p < 0.001), IV location (p = 0.056), and the number of previous successful IV attempts (p = 0.039), whereas the number of total previous IV attempts was not significantly associated (p = 0.871). In the multivariate logistic regression model, only IV catheter size had a significant association (p < 0.001), with a larger-bore IV catheter size associated with higher success. Conclusion. In this retrospective study, larger IV catheter size, but not the prehospital providers’ previous years experience, was associated with successful IV placement in adult patients. These data fail to support requirements for a minimum number of yearly IV placements by full-time paramedics to improve success rates.

Emergency physician recognition of delirium

Objective To compare the recognition of delirium by emergency physicians based on observations made during routine clinical care with concurrent ratings made by a trained researcher after formal cognitive assessment and to examine each of the four individual features of delirium separately to determine the variation in identification across features. Methods In a prospective study, a convenience sample of 259 patients, aged ≥65 years, who presented to two urban, teaching hospital emergency departments (EDs) in Western Pennsylvania between 21 June and 29 August 2011, underwent paired delirium ratings by an emergency physician and a trained researcher. Emergency physicians were asked to use their clinical judgment to decide whether the patient had any of the following delirium features: (1) acute change in mental status, (2) inattention, (3) disorganised thinking and (4) altered level of consciousness. Questions were prompted with examples of delirium features from the Confusion Assessment Method. Concurrently, a trained researcher interviewed surrogates to determine feature 1, conducted a cognitive test for delirium (Confusion Assessment Method for the intensive care unit) to determine delirium features 2 and 3 and used the Richmond Agitation and Sedation Scale to determine feature 4. Results In the 2-month study period, trained researchers identified delirium in 24/259 (9%; 95% CI 0.06 to 0.13) older patients admitted to the ED. However, attending emergency physicians recognised delirium in only 8 of the 24 and misidentified delirium in a further seven patients. Emergency physicians were particularly poor at recognising altered level of consciousness but were better at recognising acute change in mental status and inattention. Conclusions When emergency physicians use routine clinical observations, they may miss diagnosing up to two-thirds of patients with delirium. Recognition of delirium can be enhanced with standardised cognitive testing.

Diagnostic Accuracy of a Rapid Checklist to Identify Delirium in Older Patients Transported by EMS

Abstract Background. The presence of delirium in elderly patients is common and has been identified as an independent marker for increased mortality and hospital-acquired complications, yet it is poorly recognized by health care providers. Early recognition of delirium in the prehospital setting has the potential to improve outcomes, but is not feasible without valid assessment tools. Objective. To determine whether use of a rapid delirium checklist by prehospital providers is a valid way to identify cases of delirium compared with a criterion standard and whether the checklist is better at identifying delirium than the Glasgow Coma Score (GCS). Methods. We conducted a prospective study at two academic, tertiary-care emergency departments (EDs) where a convenience sample of matched dyads of emergency medical services providers and elderly patients (age ≥65 years) were enrolled. Prehospital providers reported limited demographics and work history about themselves. They also reported vital signs and GCS for each patient and completed the checklist asking about presence of the four features of delirium. The patient then underwent a cognitive assessment using the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) by a trained investigator, which was used as the criterion standard. Criterion validity and concurrent validity of the delirium checklist and abnormal GCS were evaluated using sensitivity and specificity. Results. Two hundred fifty-nine matched dyads were studied. Delirium occurred in 24 (9%) of the elderly patients sampled. Prehospital providers’ recognition of any delirium symptom resulted in a sensitivity of 0.63 (95% confidence interval [CI] 0.43–0.79) and a specificity of 0.74 (95% CI 0.73–0.84). Prehospital report of a GCS <15 has a sensitivity of 0.67 (95% CI 0.47–0.82) and a specificity of 0.85 (95% CI 0.80–0.89). Conclusions. A rapid delirium checklist can identify 63% of patients with delirium, but performed no better than the GCS. Future research should determine whether a rapid test of cognition improves early identification of elderly patients with delirium. Key words: elderly; delirium; checklist; emergency medical services