Steve A. Aguilar

ASSESSMENT OF THE ADDITION OF PREHOSPITAL CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP) TO AN URBAN EMERGENCY MEDICAL SERVICES (EMS) SYSTEM IN PERSONS WITH SEVERE RESPIRATORY DISTRESS

BACKGROUND The use of continuous positive airway pressure (CPAP) assisted ventilation in the emergency department(ED) has been well described. OBJECTIVES The purpose of this study was to measure the efficacy of adding pre-hospital CPAP to an urban emergency medical service (EMS) respiratory distress protocol on persons with respiratory distress. METHODS A historical cohort analysis of consecutive patients between 2005 and 2010. Groups were matched for severity of respiratory distress. Physiologic variables were the primary outcome obtained from first responders and upon triage in the ED. Additional outcomes included endotracheal intubation rate, hospital mortality, overall hospital length of stay(LOS), intensive care unit (ICU) admission, and ICU length of stay (ICU LOS). RESULTS There were 410 consecutive patients with predetermined criteria for severe respiratory distress, 235 historical controls matched with 175 post-implementation patients. Average age was 67 years, 54% being male. There were significant median differences in heart and respiratory rates favoring the historical cohort (p < 0.05). There were no significant differences in intubation rate, overall hospital LOS, ICU admission rate, ICU LOS, and hospital mortality (p > 0.05).Patients that were continued on noninvasive ventilatory assistance had a significantly improved rate of intubation and ICU LOS (p < 0.05). CONCLUSIONS The addition of CPAP to our pre-hospital respiratory distress protocol did not improve physiologic variables.There were no differences in overall and ICU LOS between groups. Persons with apparent continued ventilatory assistance appeared to have improved rates of intubation and ICU LOS [corrected].

Pre-Hospital Electrocardiography by Emergency Medical Personnel: Effects on Scene and Transport Times for Chest Pain and ST-Segment Elevation Myocardial Infarction Patients

OBJECTIVES This study sought to measure the impact of pre-hospital (PH) electrocardiography (ECG) on scene-to-hospital time for patients with chest pain of cardiac origin and those with ST-segment elevation myocardial infarction (STEMI). BACKGROUND Pre-hospital ECG decreases door-to balloon (D2B) time for STEMI patients. However, obtaining a PH ECG might prolong scene time. We investigated the impact of obtaining a PH ECG on both scene and transport times for patients with chest pain suspected of cardiac origin. METHODS City of San Diego Emergency Medical System runsheets of patients with chest pain from January 2003 to April 2008 were analyzed. The scene times and transport times were compared before (from January 2003 to December 2005) and after (from January 2006 to April 2008) implementation of the PH ECG. Among patients with a PH ECG, median scene times and transport times were compared in patients with and without STEMI. RESULTS There were 21,742 patients evaluated for chest pain during the study period. Implementation of PH ECG resulted in minimal increases in median scene time (19 min, 10 s vs. 19 min, 28 s, p = 0.002) and transport time (13 min, 16 s vs. 13 min, 28 s, p = 0.007). However, compared with chest pain patients, in STEMI patients (n = 303), shorter median scene time (17 min, 51 s vs. 19 min, 31 s, p < 0.001), transport time (12 min, 34 s vs. 13 min, 31 s, p = 0.006), and scene-to-hospital time was observed (30 min, 45 s vs. 33 min, 29 s, p < 0.001). CONCLUSIONS Obtaining a PH ECG for patients with chest pain minimally prolongs scene and transport times. Further, for STEMI patients, both scene times and transport times are actually reduced leading to a potential reduction in total ischemic time.

Clinical ResearchAcute Coronary SyndromesPre-Hospital Electrocardiography by Emergency Medical Personnel: Effects on Scene and Transport Times for Chest Pain and ST-Segment Elevation Myocardial Infarction Patients

OBJECTIVES This study sought to measure the impact of pre-hospital (PH) electrocardiography (ECG) on scene-to-hospital time for patients with chest pain of cardiac origin and those with ST-segment elevation myocardial infarction (STEMI). BACKGROUND Pre-hospital ECG decreases door-to balloon (D2B) time for STEMI patients. However, obtaining a PH ECG might prolong scene time. We investigated the impact of obtaining a PH ECG on both scene and transport times for patients with chest pain suspected of cardiac origin. METHODS City of San Diego Emergency Medical System runsheets of patients with chest pain from January 2003 to April 2008 were analyzed. The scene times and transport times were compared before (from January 2003 to December 2005) and after (from January 2006 to April 2008) implementation of the PH ECG. Among patients with a PH ECG, median scene times and transport times were compared in patients with and without STEMI. RESULTS There were 21,742 patients evaluated for chest pain during the study period. Implementation of PH ECG resulted in minimal increases in median scene time (19 min, 10 s vs. 19 min, 28 s, p = 0.002) and transport time (13 min, 16 s vs. 13 min, 28 s, p = 0.007). However, compared with chest pain patients, in STEMI patients (n = 303), shorter median scene time (17 min, 51 s vs. 19 min, 31 s, p < 0.001), transport time (12 min, 34 s vs. 13 min, 31 s, p = 0.006), and scene-to-hospital time was observed (30 min, 45 s vs. 33 min, 29 s, p < 0.001). CONCLUSIONS Obtaining a PH ECG for patients with chest pain minimally prolongs scene and transport times. Further, for STEMI patients, both scene times and transport times are actually reduced leading to a potential reduction in total ischemic time.

Gender differences in scene time, transport time, and total scene to hospital arrival time determined by the use of a prehospital electrocardiogram in patients with complaint of chest pain.

BACKGROUND Recent studies have described a gender bias against women in the setting of acute coronary syndrome (ACS). OBJECTIVES We sought to measure the impact that a prehospital electrocardiogram (PH ECG) has on prehospital total scene time to hospital arrival time, comparing men and women with the complaint of chest pain (cCP). METHODS This study retrospectively analyzed San Diego Emergency Medical Services (EMS) runsheets of patients with cCP before and after implementation of the PH ECG protocol. The average scene time (ST), transport time (TT), and total scene-to-arrival-at-hospital time (STH) were compared. After stratification by gender, times were compared in patients with ST-elevation myocardial infarction (STEMI) to those without STEMI. RESULTS Of 21,742 EMS activations for patients with cCP, there were no significant differences overall. When stratified by gender, there was a significant reduction of ST (00:19:16 min vs. 00:20:48 min, p<0.001, 95% CI 00:01:17-00:01:48) and STH (00:33:22 min vs. 00:35:44 min, p<0.001, 95% CI 00:01:21-00:02:24) favoring men in cases without STEMI. In cases of STEMI, men had a significant reduction in ST (00:17:27 min vs. 00:20:29 min, p<0.001, 95% CI 00:01:24-00:04:40) and STH (00:30:30 min vs. 00:34:25 min, p<0.01, 95% CI 00:01:23-00:06:26) times compared to women. CONCLUSION Prehospital ECG implementation led to no significant differences in pre- and post-implementation times. In cases of STEMI, men had significantly reduced scene time and scene-to-hospital time when compared to women. The precise reason for these disparities remains unknown.

A novel configuration of a traditional rapid response team decreases non–intensive care unit arrests and overall hospital mortality

BACKGROUND In-hospital cardiopulmonary arrest (CPA) accounts for substantial morbidity and mortality. Rapid response teams (RRTs) are designed to prevent non-intensive care unit (ICU) CPA through early detection and intervention. However, existing evidence has not consistently demonstrated a clear benefit. OBJECTIVE To explore the effectiveness of a novel RRT program design to decrease non-ICU CPA and overall hospital mortality. METHODS This study was conducted from the start of fiscal year 2005 to 2011. In November 2007, our hospitals implemented RRTs as part of a novel resuscitation program. Charge nurses from each inpatient unit underwent training as unit-specific RRT members. Additionally, all inpatient staff received annual training in RRT concepts including surveillance and recognition of deterioration. We compared the incidence of ICU and non-ICU CPA from first complete preimplementation year 2006 to postimplementation years 2007 to 2011. Overall hospital mortality was also reported. RESULTS The incidence of non-ICU CPA decreased, whereas the incidence of ICU CPA remained unchanged. Overall hospital mortality also decreased (2.12% to 1.74%, P < 0.001). The year-over-year change in RRT activations was inversely related to the change in Code Blue activations for each inpatient unit (r = -0.68, P < 0.001). CONCLUSION Our novel RRT program was associated with a decreased incidence of non-ICU CPA and improved hospital mortality.

Latency and Loss of Pulse Oximetry Signal with the Use of Digital Probes during Prehospital Rapid-Sequence Intubation

Abstract Background. Prehospital personnel rely on timely and accurate pulse oximetry data when performing critical skills, such as rapid-sequence intubation (RSI). However, loss of signal may be a frequent occurrence in patients with poor peripheral perfusion. In addition, a delay or latency period in the timeliness of pulse oximetry data may exist with probes placed on the fingers. Objective. To define the incidence of pulse oximetry signal loss or a latent period during prehospital RSI. Methods. Patients with severe traumatic brain injury (TBI) (Glasgow Coma Scale score [[GCS]] 3–8) undergoing prehospital RSI by air medical crews were enrolled. Data from hand-held oximetry–capnometry units were analyzed for either the loss of a pulse oximetry tracing (≥ 30 seconds) during the RSI procedure or the presence of a latent period, defined by the saturation of peripheral oxygen (SpO2) nadir occurring after intubation in patients undergoing desaturation (SpO2 ≤ 93%%) during the procedure. Results. A total of 98 of 124 patients (79%%, 95%% confidence interval [[CI]] 71–85%%) had pulse oximetry failure during critical points in the RSI procedure. In the 49 patients with a desaturation during RSI, a latent period was observed in 27 patients (55%%, 95%% CI 41–68%%). Conclusions. A high incidence of pulse oximetry failure was observed with the use of a digital pulse oximetry probe during prehospital RSI. In addition, a latent period appears to exist in the majority of patients undergoing desaturation.

Latency of Pulse Oximetry Signal with Use of Digital Probes Associated with Inappropriate Extubation during Prehospital Rapid Sequence Intubation in Head Injury Patients: Case Examples

BACKGROUND Endotracheal intubation remains the definitive skill needed for airway management of both medical and surgical patients treated in the prehospital and hospital arenas. Subsequently, rapid sequence intubation (RSI) protocols have been established for various first-line emergency service providers. Because RSI results in the paralysis of skeletal muscles, with a subsequent period of apnea and an increased potential for oxygen desaturation, the accuracy of pulse oximetry (SpO(2)) data is critical in guiding pre-oxygenation efforts and indicating abandonment of intubation attempts to avoid hypoxic injury. Latency of up to 120 s has been demonstrated in conditions producing peripheral vasoconstriction. The influence of peripheral oximetry on the decision-making process during the establishment of a definitive airway has not, to our knowledge, been previously investigated in the prehospital setting. OBJECTIVE To demonstrate how signal latency may manifest itself as a perceived oxygen desaturation with a subsequent premature abortion of a primary RSI attempt or erroneous extubation. CASE EXAMPLES We document endotracheal extubation associated with pulse oximetry signal latency during prehospital RSI with the use of digital SpO(2) probes. Two case examples are presented that are taken from a retrospective analysis of pre-hospital RSI data recorded by the City of San Diego Emergency Medical Services. CONCLUSION To avoid the possibility of mistaking oximetry signal latency for oxygen desaturation during pre-hospital RSI, we propose a conservative approach of aggressive pre-oxygenation to SpO(2) values≥94%, and the use of quantitative continuous capnometry for decision-making regarding whether the endotracheal tube is correctly placed. In cases of hypoxemia despite a properly placed tube, focus should be turned to other causes of post intubation hypoxemia.

A Conceptual Framework to Reduce Inpatient Preventable Deaths

BACKGROUND Efforts to reduce preventable deaths in the in-hospital setting should target both cardiopulmonary arrest (CPA) prevention and optimal resuscitation. This requires consideration of a broad range of clinical issues and processes. A comprehensive, integrated system of care (SOC) that links data collection with a modular education program to reduce preventable deaths has not been defined. METHODS This study was conducted in two urban university hospitals from 2005 to 2009. The Advanced Resuscitation Training (ART) program was implemented in 2007, incorporating hands-on resuscitative skills and in-hospital-specific training with an institutional resuscitation database. Linkage between the database and training modules occurs via the ART Matrix, which classifies all CPA events into the following etiologies: sepsis, hemorrhage, pulmonary embolus, heart failure, tachyarrhythmias, bradyarrhythmias, acute respiratory distress syndrome, non-intubated pulmonary disease, obstructive apnea, traumatic brain injury, ischemic brain injury, and intracranial mass lesions. This taxonomy was validated using descriptive statistics, before-and-after analysis evaluating CPA incidence, and multivariate logistic regression to predict CPA survival. RESULTS A total of 336 inpatients suffered a cardiopulmonary arrest during the study period-187 in the pre-ART period and 149 in the post-ART period. The vast majority of CPA events were categorized using the ART Matrix with high inter-observer reliability. As anticipated, changes in CPA incidence and survival were observed for some Matrix categories but not others following ART implementation. In addition, multivariate logistic regression revealed strong independent associations between taxonomy classifications and outcome. CONCLUSION A novel SOC using a unique taxonomy for arrest classification appears to be effective at reducing inpatient CPA incidence and outcome.

Preliminary Report of a Mathematical Model of Ventilation and Intrathoracic Pressure Applied to Prehospital Patients with Severe Traumatic Brain Injury

Abstract Background: Inadvertent hyperventilation is associated with poor outcomes from traumatic brain injury (TBI). Hypocapnic cerebral vasoconstriction is well described and causes an immediate and profound decrease in cerebral perfusion. The hemodynamic effects of positive-pressure ventilation (PPV) remain incompletely understood but may be equally important, particularly in the hypovolemic patient with TBI. Objective: Preliminary report on the application of a previously described mathematical model of perfusion and ventilation to prehospital data to predict intrathoracic pressure. Methods: Ventilation data from 108 TBI patients (76 ground transported, 32 helicopter transported) were used for this analysis. Ventilation rate (VR) and end-tidal carbon dioxide (PetCO2) values were used to estimate tidal volume (VT). The values for VR and estimated VT were then applied to a previously described mathematical model of perfusion and ventilation. This model allows input of various lung parameters to define a pressure–volume relationship, then derives mean intrathoracic pressure (MITP) for various VT and VR values. For this analysis, normal lung parameters were utilized. Separate analyses were performed assuming either fixed or variable PaCO2–PetCO2 differences. Ground and air medical patients were compared with regard to VR, PetCO2, estimated VT, and predicted MITP. Results: A total of 10,647 measurements were included from the 108 TBI patients, representing about 13 minutes of ventilation per patient. Mean VR values were higher for ground patients versus air patients (21.6 vs. 19.7 breaths/min; p < 0.01). Estimated VT values were similar for ground and air patients (399 mL vs. 392 mL; p = NS) in the fixed model but not the variable (636 vs. 688 mL, respectively; p < 0.01). Mean PetCO2 values were lower for ground versus air patients (30.6 vs. 33.8 mmHg; p < 0.01). Predicted MITP values were higher for ground versus air patients, assuming either fixed (9.0 vs. 8.1 mmHg; p < 0.01) or variable (10.9 vs. 9.7 mmHg; p < 0.01) PaCO2–PetCO2 differences. Conclusions: Predicted MITP values increased with ventilation rates. Future studies to externally validate this model are warranted.

Reply to “Statistical Errors in a Recent Article in the Journal”

admissions and 69 non-ICU admissions for patients who did receive CPAP in the ED, the one-tailed p value obtained using Yates’ correction for the comparison is 0.146, not the reported value of 0.012. The erroneous p values reported by the authors in Table 6 led them to unnecessary speculation in paragraph six of the Discussion, regarding possible reasons that lack of continuation of CPAP in the ED might increase the probability of intubation and ICU admission. Such speculation would not have been needed if correct statistical results had been obtained. In addition, the authors’ Discussion stated that there was a “trend” toward a decreased hospital length of stay (4 days vs. 3) and length of ICU stay (3 days vs. 2) for patients who received prehospital CPAP compared to the historical controls noted in Table 4 who did not receive prehospital CPAP. The p values for these comparisons were reported in Table 4 to be 0.342 and 0.217, respectively. Statistical analysis of the data merely indicates how likely numerical differences observed between groups were due to chance alone. The data indicate that there was a 34.2% probability that the numerical difference in length of hospital stay, and a 21.7% chance that the difference in ICU length of stay, were due simply to chance. Trend is not a proper statistical term. The authors may have conducted a study that was underpowered to detect a statistically significant difference of hospital or ICU length of stay, but the authors should not have used the term trend to overstate the meaning of the numerical differences of hospital and ICU length of stay observed.