David Carlbom

Pilot Randomized Clinical Trial of Prehospital Induction of Mild Hypothermia in Out-of-Hospital Cardiac Arrest Patients With a Rapid Infusion of 4°C Normal Saline

Background— Although delayed hospital cooling has been demonstrated to improve outcome after cardiac arrest, in-field cooling started immediately after the return of spontaneous circulation may be more beneficial. The aims of the present pilot study were to assess the feasibility, safety, and effectiveness of in-field cooling. Methods and Results— We determined the effect on esophageal temperature, before hospital arrival, of infusing up to 2 L of 4°C normal saline as soon as possible after resuscitation from out-of-hospital cardiac arrest. A total of 125 such patients were randomized to receive standard care with or without intravenous cooling. Of the 63 patients randomized to cooling, 49 (78%) received an infusion of 500 to 2000 mL of 4°C normal saline before hospital arrival. These 63 patients experienced a mean temperature decrease of 1.24±1°C with a hospital arrival temperature of 34.7°C, whereas the 62 patients not randomized to cooling experienced a mean temperature increase of 0.10±0.94°C (P<0.0001) with a hospital arrival temperature of 35.7°C. In-field cooling was not associated with adverse consequences in terms of blood pressure, heart rate, arterial oxygenation, evidence for pulmonary edema on initial chest x-ray, or rearrest. Secondary end points of awakening and discharged alive from hospital trended toward improvement in ventricular fibrillation patients randomized to in-field cooling. Conclusions— These pilot data suggest that infusion of up to 2 L of 4°C normal saline in the field is feasible, safe, and effective in lowering temperature. We propose that the effect of this cooling method on neurological outcome after cardiac arrest be studied in larger numbers of patients, especially those whose initial rhythm is ventricular fibrillation.

Effect of prehospital induction of mild hypothermia on survival and neurological status among adults with cardiac arrest: a randomized clinical trial.

IMPORTANCE Hospital cooling improves outcome after cardiac arrest, but prehospital cooling immediately after return of spontaneous circulation may result in better outcomes. OBJECTIVE To determine whether prehospital cooling improves outcomes after resuscitation from cardiac arrest in patients with ventricular fibrillation (VF) and without VF. DESIGN, SETTING, AND PARTICIPANTS A randomized clinical trial that assigned adults with prehospital cardiac arrest to standard care with or without prehospital cooling, accomplished by infusing up to 2 L of 4°C normal saline as soon as possible following return of spontaneous circulation. Adults in King County, Washington, with prehospital cardiac arrest and resuscitated by paramedics were eligible and 1359 patients (583 with VF and 776 without VF) were randomized between December 15, 2007, and December 7, 2012. Patient follow-up was completed by May 1, 2013. Nearly all of the patients resuscitated from VF and admitted to the hospital received hospital cooling regardless of their randomization. MAIN OUTCOMES AND MEASURES The primary outcomes were survival to hospital discharge and neurological status at discharge. RESULTS The intervention decreased mean core temperature by 1.20°C (95% CI, -1.33°C to -1.07°C) in patients with VF and by 1.30°C (95% CI, -1.40°C to -1.20°C) in patients without VF by hospital arrival and reduced the time to achieve a temperature of less than 34°C by about 1 hour compared with the control group. However, survival to hospital discharge was similar among the intervention and control groups among patients with VF (62.7% [95% CI, 57.0%-68.0%] vs 64.3% [95% CI, 58.6%-69.5%], respectively; P = .69) and among patients without VF (19.2% [95% CI, 15.6%-23.4%] vs 16.3% [95% CI, 12.9%-20.4%], respectively; P = .30). The intervention was also not associated with improved neurological status of full recovery or mild impairment at discharge for either patients with VF (57.5% [95% CI, 51.8%-63.1%] of cases had full recovery or mild impairment vs 61.9% [95% CI, 56.2%-67.2%] of controls; P = .69) or those without VF (14.4% [95% CI, 11.3%-18.2%] of cases vs 13.4% [95% CI,10.4%-17.2%] of controls; P = .30). Overall, the intervention group experienced rearrest in the field more than the control group (26% [95% CI, 22%-29%] vs 21% [95% CI, 18%-24%], respectively; P = .008), as well as increased diuretic use and pulmonary edema on first chest x-ray, which resolved within 24 hours after admission. CONCLUSION AND RELEVANCE Although use of prehospital cooling reduced core temperature by hospital arrival and reduced the time to reach a temperature of 34°C, it did not improve survival or neurological status among patients resuscitated from prehospital VF or those without VF. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00391469.

Pilot Study of Rapid Infusion of 2 L of 4°C Normal Saline for Induction of Mild Hypothermia in Hospitalized, Comatose Survivors of Out-of-Hospital Cardiac Arrest

Background—Recent clinical studies have demonstrated that mild hypothermia (32°C to 34°C) induced by surface cooling improves neurological outcome after resuscitation from out-of-hospital cardiac arrest. Results from animal models suggest that the effectiveness of mild hypothermia could be improved if initiated as soon as possible after return of spontaneous circulation. Infusion of cold, intravenous fluid has been proposed as a safe, effective, and inexpensive technique to induce mild hypothermia after cardiac arrest. Methods and Results—In 17 hospitalized survivors of out-of-hospital cardiac arrest, we determined the effect on temperature and hemodynamics of infusing 2 L of 4°C cold, normal saline during 20 to 30 minutes into a peripheral vein with a high-pressure bag. Data on vital signs, electrolytes, arterial blood gases, and coagulation were collected before and after fluid infusion. Cardiac function was assessed by transthoracic echocardiography before fluid administration and 1 hour after infusion. Passive (fans, leaving patient uncovered) or active (cooling blankets, neuromuscular blockade) cooling measures were used to maintain mild hypothermia for 24 hours. Infusion of 2 L of 4°C cold, normal saline resulted in a mean temperature drop of 1.4°C 30 minutes after the initiation of infusion. Rapid infusion of fluid was not associated with clinically important changes in vital signs, electrolytes, arterial blood gases, or coagulation parameters. The initial mean ejection fraction was 34%, and fluid infusion did not affect ejection fraction or increase central venous pressure, pulmonary pressures, or left atrial filling pressures as assessed by echocardiography. Passive measures were ineffective in maintaining hypothermia compared with active measures. Conclusions—Infusion of 2 L of 4°C cold, normal saline is safe and effective in rapidly lowering body temperature in survivors of out-of-hospital cardiac arrest.

Barriers to implementing protocol-based sepsis resuscitation in the emergency department - Results of a national survey

Objective:To identify barriers to implementation of a written protocol for early goal-directed therapy for severe sepsis in the busiest emergency departments in the United States. Design:Telephone survey with both quantitative and qualitative analysis. Setting:Two busiest teaching and two busiest nonteaching emergency departments in each of the 25 most densely populated combined statistical areas in the United States. Subjects:Twenty-four physician directors and 40 nursing managers representing 53% of the 100 emergency departments surveyed. Interventions:Survey questionnaire. Measurements and Main Results:Respondents identified lack of available nursing staff to perform the procedure, the inability to monitor central venous pressure in the emergency department, and challenges in identifying septic patients as the most frequent barriers. Although nurse managers and physicians identified similar barriers, nurses were more likely than physicians to list central venous catheter insertion as an important barrier (38% vs. 5%; p = .01), and physicians were more likely to endorse lack of agreement with the early goal-directed therapy resuscitation protocol (16% vs. 0%; p = .03). There were no statistically significant differences in the rankings assigned by clinicians from teaching and nonteaching hospitals. Qualitative analysis of open-ended questions identified barriers in a number of areas, including barriers to initiating the protocol process and factors that distinguish sepsis from other time-sensitive diseases in the emergency department. Conclusions:Nurse managers and physician directors of busy emergency departments representing the largest urban areas in the United States identify multiple barriers to implementing time-sensitive resuscitation to patients with severe sepsis. More than half of all respondents recognized a critical shortage of nursing staff, problems in obtaining central venous pressure monitoring, and challenges in identification of patients with sepsis as the largest roadblocks to overcome in implementing early goal-directed therapy.

Paramedic Training for Proficient Prehospital Endotracheal Intubation

Abstract Background. Emergency airway management is an important component of resuscitation of critically ill patients. Multiple studies demonstrate variable endotracheal intubation (ETI) success by prehospital providers. Data describing how many ETI training experiences are required to achieve high success rates are sparse. Objectives. To describe the relationship between the number of prehospital ETI experiences and the likelihood of success on subsequent ETI and to specifically look at uncomplicated first-pass ETI in a university-based training program with substantial resources. Methods. We conducted a secondary analysis of a prospectively collected cohort of paramedic student prehospital intubation attempts. Data collected on prehospital ETIs included indication, induction agents, number of direct laryngoscopy attempts, and advanced airway procedures performed. We used multivariable generalized estimating equations (GEE) analysis to determine the effect of cumulative ETI experience on first-pass and overall ETI success rates. Results. Over a period of three years, 56 paramedic students attempted 576 prehospital ETIs. The odds of overall ETI success were associated with cumulative ETI experience (odds ratio [OR] 1.097 per encounter, 95% confidence interval [CI] = 1.026–1.173, p = 0.006). The odds of first-pass ETI success were associated with cumulative ETI experience (OR 1.061 per encounter, 95% CI = 1.014–1.109, p = 0.009). Conclusion. In a training program with substantial clinical opportunities and resources, increased ETI success rates were associated with increasing clinical exposure. However, first-pass placement of the ETT with a high success rate requires high numbers of ETI training experiences that may exceed the number available in many training programs.

The Utility of Early End-Tidal Capnography in Monitoring Ventilation Status After Severe Injury

BACKGROUND An arterial CO2 (Paco2) of 30 mm Hg to 39 mm Hg has been shown to be the ideal target range for early ventilation in trauma patients; however, this requires serial arterial blood gases. The use of end-tidal capnography (EtCO2) has been recommended as a surrogate measure of ventilation in the prehospital arena. This is based on the observation of close EtCO2 Pa(CO2) correlation in healthy patients, yet trauma patients frequently suffer from impaired pulmonary ventilation/perfusion. Thus, we hypothesize that EtCO2 will demonstrate a poor reflection of actual ventilation status after severe injury. METHODS Prospective observational study on consecutive intubated trauma patients treated in our emergency department (ED) during 9 months. Arterial blood gas values and concomitant EtCO2 levels were recorded. Regression was used to determine the strength of correlation among all trauma patients and subgroups based on injury severity (Abbreviated Injury Score and Injury Severity Score) and physiologic markers of perfusion status (lactate, shock index, and arterial base deficit). RESULTS During 9 months, 180 patients were evaluated. The EtCO2 Paco2 correlation was poor at R2 = 0.277. Patients ventilated in the recommended EtCO2 (range, 35 to 40) were likely to be under ventilated (Pa(CO2) > 40 mm Hg) 80% of the time, and severely under ventilated (Pa(CO2) > 50 mm Hg) 30% of the time. Correlation was best for patients with isolated traumatic brain injury and worst for those with evidence of poor tissue perfusion. CONCLUSION EtCO2 has low correlation with Pa(CO2), and therefore should not be used to guide ventilation in intubated trauma patients in the ED. Better strategies for guiding prehospital and ED ventilation are needed.

The Process of Prehospital Airway Management: Challenges and Solutions During Paramedic Endotracheal Intubation

Objectives:Endotracheal intubation success rates in the prehospital setting are variable. Our objective was to describe the challenges encountered and corrective actions taken during the process of endotracheal intubation by paramedics. Design:Analysis of prehospital airway management using a prospective registry that was linked to an emergency medical services administrative database. Setting:Emergency medical services system serving King County, Washington, 2006–2011. Paramedics in this system have the capability to administer neuromuscular blocking agents to facilitate intubation (i.e., rapid sequence intubation). Patients:A total of 7,523 patients more than 12 years old in whom paramedics attempted prehospital endotracheal intubation. Interventions:None. Measurements and Main Results:An intubation attempt was defined as the introduction of the laryngoscope into the patient’s mouth, and the attempt concluded when the laryngoscope was removed from the mouth. Endotracheal intubation was successful on the first attempt in 77% and ultimately successful in 99% of patients (7,433 of 7,523). Paramedics used a rapid sequence intubation strategy on 54% of first attempts. Among the subset with a failed first attempt (n = 1,715), bodily fluids obstructing the laryngeal view (50%), obesity (28%), patient positioning (17%), and facial or spinal trauma (6%) were identified as challenges to intubation. A variety of adjustments were made to achieve intubation success, including upper airway suctioning (used in 43% of attempts resulting in success), patient repositioning (38%), rescue bougie use (19%), operator change (16%), and rescue rapid sequence intubation (6%). Surgical cricothyrotomy (0.4%, n = 27) and bag-valve-mask ventilation (0.8%, n = 60) were rarely performed by paramedics as final rescue airway strategies. Conclusions:Airway management in the prehospital setting has substantial challenges. Success can require a collection of adjustments that involve equipment, personnel, and medication often in a simultaneous fashion.

Volume Overload: Prevalence, Risk Factors, and Functional Outcome in Survivors of Septic Shock

RATIONALE Survivors of septic shock have impaired functional status. Volume overload is associated with poor outcomes in patients with septic shock, but the impact of volume overload on functional outcome and discharge destination of survivors is unknown. OBJECTIVES This study describes patterns of fluid management both during and after septic shock. We examined factors associated with volume overload upon intensive care unit (ICU) discharge. We then examined associations between volume overload upon ICU discharge, mobility limitation, and discharge to a healthcare facility in septic shock survivors, with the hypothesis that volume overload is associated with increased odds of these outcomes. METHODS We retrospectively reviewed the medical records of 247 patients admitted with septic shock to an academic county hospital between June 2009 and April 2012 who survived to ICU discharge. We defined volume overload as a fluid balance expected to increase the subjects admission weight by 10%. Statistical methods included unadjusted analyses and multivariable logistic regression. MEASUREMENTS AND MAIN RESULTS Eighty-six percent of patients had a positive fluid balance, and 35% had volume overload upon ICU discharge. Factors associated with volume overload in unadjusted analyses included more severe illness, cirrhosis, blood transfusion during shock, and higher volumes of fluid administration both during and after shock. Blood transfusion during shock was independently associated with increased odds of volume overload (odds ratio [OR], 2.65; 95% confidence interval [CI], 1.33-5.27; P = 0.01) after adjusting for preexisting conditions and severity of illness. Only 42% of patients received at least one dose of a diuretic during their hospitalization. Volume overload upon ICU discharge was independently associated with inability to ambulate upon hospital discharge (OR, 2.29; 95% CI, 1.24-4.25; P = 0.01) and, in patients admitted from home, upon discharge to a healthcare facility (OR, 2.34; 95% CI, 1.1-4.98; P = 0.03). CONCLUSIONS Volume overload is independently associated with impaired mobility and discharge to a healthcare facility in survivors of septic shock. Prevention and treatment of volume overload in patients with septic shock warrants further investigation.

Pediatric Intubation by Paramedics in a Large Emergency Medical Services System: Process, Challenges, and Outcomes

STUDY OBJECTIVE Pediatric intubation is a core paramedic skill in some emergency medical services (EMS) systems. The literature lacks a detailed examination of the challenges and subsequent adjustments made by paramedics when intubating children in the out-of-hospital setting. We undertake a descriptive evaluation of the process of out-of-hospital pediatric intubation, focusing on challenges, adjustments, and outcomes. METHODS We performed a retrospective analysis of EMS responses between 2006 and 2012 that involved attempted intubation of children younger than 13 years by paramedics in a large, metropolitan EMS system. We calculated the incidence rate of attempted pediatric intubation with EMS and county census data. To summarize the intubation process, we linked a detailed out-of-hospital airway registry with clinical records from EMS, hospital, or autopsy encounters for each child. The main outcome measures were procedural challenges, procedural success, complications, and patient disposition. RESULTS Paramedics attempted intubation in 299 cases during 6.3 years, with an incidence of 1 pediatric intubation per 2,198 EMS responses. Less than half of intubations (44%) were for patients in cardiac arrest. Two thirds of patients were intubated on the first attempt (66%), and overall success was 97%. The most prevalent challenge was body fluids obscuring the laryngeal view (33%). After a failed first intubation attempt, corrective actions taken by paramedics included changing equipment (33%), suctioning (32%), and repositioning the patient (27%). Six patients (2%) experienced peri-intubation cardiac arrest and 1 patient had an iatrogenic tracheal injury. No esophageal intubations were observed. Of patients transported to the hospital, 86% were admitted to intensive care and hospital mortality was 27%. CONCLUSION Pediatric intubation by paramedics was performed infrequently in this EMS system. Although overall intubation success was high, a detailed evaluation of the process of intubation revealed specific challenges and adjustments that can be anticipated by paramedics to improve first-pass success, potentially reduce complications, and ultimately improve clinical outcomes.

Effect of Prehospital Induction of Mild Hypothermia on 3‐Month Neurological Status and 1‐Year Survival Among Adults With Cardiac Arrest: Long‐Term Follow‐up of a Randomized, Clinical Trial

Background Randomized trials of prehospital cooling after cardiac arrest have shown that neither prehospital cooling nor targeted temperature management differentially affected short‐term survival or neurological function. In this follow‐up study, we assess the association of prehospital hypothermia with neurological function at least 3 months after cardiac arrest and survival 1 year after cardiac arrest. Methods and Results There were 508 individuals who were discharged alive from hospitals in King County, Washington; 373 (73%) were interviewed by telephone 123±43 days after the initial event. Overall, 59% of the treatment group and 58% of the control group had Cerebral Performance Category (CPC) 1 or 2 (P=0.70), and 50% of the treatment group and 49% of the control group had slight disability or better by the Modified Rankin Scale (MRS; (P=0.35). One‐year survival was 87% in the treatment group and 84% in the control group (P=0.42). Of those with CPC 1 at hospital discharge, 68% had CPC 1 or 2 at follow‐up, and 59% had MRS of slight disability or better. Of 41 patients with CPC 3 or 4 at discharge, only 12% had CPC 2 at follow‐up, and just 5% had MRS of slight disability or better. One‐year survival was 92% for CPC 1 at discharge, but only 40% for CPC 4. Conclusion In addition to excellent survival, patients who had good neurological function at discharge continued to have good function at least 3 months after the event. Clinical Trial Registration URL: Clinicaltrials.gov. Unique identifier: NCT00391469