Impact of noninvasive ventilation at a municipal emergency department on ICU admissions.

BACKGROUND: In 2015, the emergency department of a municipal hospital in Vienna began to perform noninvasive ventilation (NIV) on patients admitted for acute respiratory failure, given no intubation criteria were met. The intention of this study was to show to which type of hospital unit patients were transferred after undergoing NIV in the emergency department. Additionally, the impact of the underlying disease, a patient's sex and age and the year of intervention were analyzed. METHODS: A single-center retrospective exploratory study was performed on 371 patients. All patients with acute respiratory failure who were noninvasively ventilated at the study center emergency department from 2015 to 2018 were eligible. Relevant data were extracted from the patient's medical records. RESULTS: A total of 43.7% (95% confidence interval, CI 38.8-48.5%) of patients were successfully stabilized in the emergency department through NIV and subsequently transferred to a normal care unit or discharged. This nonintensive care admission rate was significantly associated with certain underlying medical conditions, age and year of intervention. A further 19.7% (95% CI 15.6-23.7%) of patients were transferred to an intermediate care unit instead of an intensive care unit. CONCLUSION: These findings emphasize the importance of noninvasive ventilation at the emergency department in reducing load on intensive care units and ensuring an efficient hospital workflow. Nonintensive care admission rate appears to be the highest in patients with pulmonary edema, especially in the higher age range and is also associated with the level of staff training. Prospective trials are needed to accurately confirm these correlations.

Evaluation of a novel, rapid antigen detection test for the diagnosis of SARS-CoV-2.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19) is currently finally determined in laboratory settings by real-time reverse-transcription polymerase-chain-reaction (rt-PCR). However, simple testing with immediately available results are crucial to gain control over COVID-19. The aim was to evaluate such a point-of-care antigen rapid test (AG-rt) device in its performance compared to laboratory-based rt-PCR testing in COVID-19 suspected, symptomatic patients. METHODS: For this prospective study, two specimens each of 541 symptomatic female (54.7%) and male (45.3%) patients aged between 18 and 95 years tested at five emergency departments (ED, n = 296) and four primary healthcare centres (PHC, n = 245), were compared, using AG-rt (positive/negative/invalid) and rt-PCR (positive/negative and cycle threshold, Ct) to diagnose SARS-CoV-2. Diagnostic accuracy, sensitivity, specificity, positive predictive values (PPV), negative predictive value (NPV), and likelihood ratios (LR+/-) of the AG-rt were assessed. RESULTS: Differences between ED and PHC were detected regarding gender, age, symptoms, disease prevalence, and diagnostic performance. Overall, 174 (32.2%) were tested positive on AG-rt and 213 (39.4%) on rt-PCR. AG correctly classified 91.7% of all rt-PCR positive cases with a sensitivity of 80.3%, specificity of 99.1%, PPV of 98.3, NPV of 88.6%, LR(+) of 87.8, and LR(-) of 0.20. The highest sensitivities and specificities of AG-rt were detected in PHC (sensitivity: 84.4%, specificity: 100.0%), when using Ct of 30 as cut-off (sensitivity: 92.5%, specificity: 97.8%), and when symptom onset was within the first three days (sensitivity: 82.9%, specificity: 99.6%). CONCLUSIONS: The highest sensitivity was detected with a high viral load. Our findings suggest that AG-rt are comparable to rt-PCR to diagnose SARS-CoV-2 in COVID-19 suspected symptomatic patients presenting both at emergency departments and primary health care centres.

Standard blood laboratory values as a clinical support tool to distinguish between SARS-CoV-2 positive and negative patients.

Standard blood laboratory parameters may have diagnostic potential, if polymerase-chain-reaction (PCR) tests are not available on time. We evaluated standard blood laboratory parameters of 655 COVID-19 patients suspected to be infected with SARS-CoV-2, who underwent PCR testing in one of five hospitals in Vienna, Austria. We compared laboratory parameters, clinical characteristics, and outcomes between positive and negative PCR-tested patients and evaluated the ability of those parameters to distinguish between groups. Of the 590 patients (20-100 years, 276 females and 314 males), 208 were PCR-positive. Positive compared to negative PCR-tested patients had significantly lower levels of leukocytes, neutrophils, basophils, eosinophils, lymphocytes, neutrophil-to-lymphocyte ratio, monocytes, and thrombocytes; while significantly higher levels were detected with erythrocytes, hemoglobin, hematocrit, C-reactive-protein, ferritin, activated-partial-thromboplastin-time, alanine-aminotransferase, aspartate-aminotransferase, lipase, creatine-kinase, and lactate-dehydrogenase. From all blood parameters, eosinophils, ferritin, leukocytes, and erythrocytes showed the highest ability to distinguish between COVID-19 positive and negative patients (area-under-curve, AUC: 72.3-79.4%). The AUC of our model was 0.915 (95% confidence intervals, 0.876-0.955). Leukopenia, eosinopenia, elevated erythrocytes, and hemoglobin were among the strongest markers regarding accuracy, sensitivity, specificity, positive and negative predictive value, positive and negative likelihood ratio, and post-test probabilities. Our findings suggest that especially leukopenia, eosinopenia, and elevated hemoglobin are helpful to distinguish between COVID-19 positive and negative tested patients.

Short structured feedback training is equivalent to a mechanical feedback device in two-rescuer BLS: a randomised simulation study.

BACKGROUND: Resuscitation guidelines encourage the use of cardiopulmonary resuscitation (CPR) feedback devices implying better outcomes after sudden cardiac arrest. Whether effective continuous feedback could also be given verbally by a second rescuer ("human feedback") has not been investigated yet. We, therefore, compared the effect of human feedback to a CPR feedback device. METHODS: In an open, prospective, randomised, controlled trial, we compared CPR performance of three groups of medical students in a two-rescuer scenario. Group "sCPR" was taught standard BLS without continuous feedback, serving as control. Group "mfCPR" was taught BLS with mechanical audio-visual feedback (HeartStart MRx with Q-CPR-Technology™). Group "hfCPR" was taught standard BLS with human feedback. Afterwards, 326 medical students performed two-rescuer BLS on a manikin for 8 min. CPR quality parameters, such as "effective compression ratio" (ECR: compressions with correct hand position, depth and complete decompression multiplied by flow-time fraction), and other compression, ventilation and time-related parameters were assessed for all groups. RESULTS: ECR was comparable between the hfCPR and the mfCPR group (0.33 vs. 0.35, p = 0.435). The hfCPR group needed less time until starting chest compressions (2 vs. 8 s, p < 0.001) and showed fewer incorrect decompressions (26 vs. 33 %, p = 0.044). On the other hand, absolute hands-off time was higher in the hfCPR group (67 vs. 60 s, p = 0.021). CONCLUSIONS: The quality of CPR with human feedback or by using a mechanical audio-visual feedback device was similar. Further studies should investigate whether extended human feedback training could further increase CPR quality at comparable costs for training.

Prehospital surface cooling is safe and can reduce time to target temperature after cardiac arrest.

PURPOSE: Mild therapeutic hypothermia proved to be beneficial when induced after cardiac arrest in humans. Prehospital cooling with i.v. fluids was associated with adverse side effects. Our primary objective was to compare time to target temperature of out-of hospital cardiac arrest patients cooled non-invasively either in the prehospital setting vs. the in-hospital (IH) setting, to assess surface-cooling safety profile and long term outcome. METHODS: In this retrospective, single center cohort study, a group of adult patients with restoration of spontaneous circulation (ROSC) after out-of hospital cardiac arrest were cooled with a surface cooling pad beginning either in the prehospital or IH setting for 24h. Time to target temperature (33.9°C), temperature on admission, time to admission after ROSC and outcome were compared. Also, rearrests and pulmonary edema were assessed. Neurologic outcome at 12 months was evaluated (Cerebral Performance Category, CPC 1-2, favorable outcome). RESULTS: Between September 2005 and February 2010, 56 prehospital cooled patients and 54 IH-cooled patients were treated. Target temperature was reached in 85 (66-117)min (prehospital) and in 135 (102-192)min (IH) after ROSC (p<0.001). After prehospital cooling, hospital admission temperature was 35.2 (34.2-35.8)°C, and in the IH-cooling patients initial temperature was 35.8 (35.2-36.3)°C (p=0.001). No difference in numbers of rearrests and pulmonary edema between groups was observed. In both groups, no skin lesions were observed. Favorable outcome was reached in 26.8% (prehospital) and in 37.0% (IH) of the patients (p=0.17). CONCLUSIONS: Using a non-invasive prehospital surface cooling method after cardiac arrest, target temperature can be reached faster without any major complications than starting cooling IH. The effect of early non-invasive cooling on long-term outcome remains to be determined in larger studies.

Where no guideline has gone before: retrospective analysis of resuscitation in the 24th century.

AIM OF THE STUDY: Evaluation of the treatment, epidemiology and outcome of cardiac arrest in the television franchise Star Trek. METHODS: Retrospective cohort study of prospective events. Screening of all episodes of Star Trek: The Next Generation, Star Trek: Deep Space Nine and Star Trek: Voyager for cardiac arrest events. Documentation was performed according to the Utstein guidelines for cardiac arrest documentation. All adult, single person cardiac arrests were included. Patients were excluded if cardiac arrest occurred during mass casualties, if the victims were annihilated by energy weapons or were murdered and nobody besides the assassin could provide first aid. Epidemiological data, treatment and outcome of cardiac arrest victims in the 24th century were studied. RESULTS: Ninety-six cardiac arrests were included. Twenty-three individuals were female (24%). Cardiac arrest was witnessed in 91 cases (95%), trauma was the leading cause (n = 38; 40%). Resuscitation was initiated in 17 cases (18%) and 12 patients (13%) had return of spontaneous circulation. Favorable neurological outcome and long-term survival was documented in nine patients (9%). Technically diagnosed cardiac arrest was associated with higher rates of favorable neurological outcome and long-term survival. Neurological outcome and survival did not depend on cardiac arrest location. CONCLUSION: Cardiac arrest remains a critical event in the 24th century. We observed a change of etiology from cardiac toward traumatic origin. Quick access to medical help and new prognostic tools were established to treat cardiac arrest.

Comparing three CPR feedback devices and standard BLS in a single rescuer scenario: a randomised simulation study.

BACKGROUND: Efficiently performed basic life support (BLS) after cardiac arrest is proven to be effective. However, cardiopulmonary resuscitation (CPR) is strenuous and rescuers' performance declines rapidly over time. Audio-visual feedback devices reporting CPR quality may prevent this decline. We aimed to investigate the effect of various CPR feedback devices on CPR quality. METHODS: In this open, prospective, randomised, controlled trial we compared three CPR feedback devices (PocketCPR, CPRmeter, iPhone app PocketCPR) with standard BLS without feedback in a simulated scenario. 240 trained medical students performed single rescuer BLS on a manikin for 8min. Effective compression (compressions with correct depth, pressure point and sufficient decompression) as well as compression rate, flow time fraction and ventilation parameters were compared between the four groups. RESULTS: Study participants using the PocketCPR performed 17±19% effective compressions compared to 32±28% with CPRmeter, 25±27% with the iPhone app PocketCPR, and 35±30% applying standard BLS (PocketCPR vs. CPRmeter p=0.007, PocketCPR vs. standard BLS p=0.001, others: ns). PocketCPR and CPRmeter prevented a decline in effective compression over time, but overall performance in the PocketCPR group was considerably inferior to standard BLS. Compression depth and rate were within the range recommended in the guidelines in all groups. CONCLUSION: While we found differences between the investigated CPR feedback devices, overall BLS quality was suboptimal in all groups. Surprisingly, effective compression was not improved by any CPR feedback device compared to standard BLS. All feedback devices caused substantial delay in starting CPR, which may worsen outcome.

Cardiac arrest caused by acute intoxication-insight from a registry.

INTRODUCTION: The aim of the study was to evaluate the epidemiology and outcome after cardiac arrest caused by intoxication. METHODS: A retrospective analysis of 1991 to 2010 medical record of patients experiencing cardiac arrest caused by self-inflicted, intentional intoxication was performed. The setting was an emergency department of a tertiary care university hospital. The primary end point was the presentation of epidemiologic data in relation to favorable neurologic outcome, defined as cerebral performance categories 1 or 2 and 180-day survival. Furthermore, the patients were subdivided into a single-substance and polysubstance group, depending on the substances causing the intoxication. RESULTS: Of 3644 patients admitted to our department, 99 (2.7%) with a median age of 26 (interquartile range, 19-42) years (37% female) were included. Cardiac arrest was witnessed in 62 cases (63%). Eleven patients (11%) received basic life support by bystanders, and 11 (11%) had a shockable rhythm in the initial electrocardiogram. The combined end point "good survival" was achieved by 34 patients (34%). Cardiac arrest occurred out of hospital in 73 patients (74%) and in-hospital in 26 patients (26%). A single substance causing the intoxication was found in 56 patients (56%). Opiates were the leading substance, with 25 patients (25%) using them. CONCLUSION: Cardiac arrest caused by intoxication is found predominately in young patients. Overall, favorable neurologic survival was achieved in 34%. Opiate-related cardiac arrest was associated with poor survival and a high incidence of neurologic deficits.

Airway management of adult patients without trauma in an ED led by internists.

BACKGROUND: Airway management is a key competence in emergency medicine. Patients heavily differ from those in the operating room. They are acutely ill by definition and usually not fasting. Evaluation of risk factors is often impossible. Current literature primarily originates from countries where emergency medicine is an independent specialty. We evaluated intubations in a high-volume emergency department run by internists and comprising its own distinctive intensive care unit. METHODS: In this prospective, noncontrolled, observational study, we continuously documented all intubations performed at the emergency department. We analyzed demographic, medical, and staff-related factors predicting difficulties during intubation using logistic regression models. RESULTS: For 73 months, 660 cases were included, 69 (10.5%) of them were without any induction therapy. Two hundred fifty-two (38.2%) patients were female, and their mean age was 59 ± 17 years. Three hundred four (49.9%) had an initial Glasgow Coma Scale of 3. Leading indications were respiratory insufficiency (n = 246; 37.3%), resuscitation (n = 172; 26.1%), and intracranial hemorrhage (n = 75; 11.4%). First attempt was successful in 465 cases (75.1%); alternative airway devices were used in 22 cases (3.3%). Time from the first intubation attempt to a validated airway was 1 minute (interquartile range, 0-2 minutes). Physicians' experience and anatomical risk factors were associated with failure at the first attempt, prolonged intubation, and the need for alternative devices. CONCLUSIONS: Airway management at the emergency department possesses a high potential of failure. Experience seems to be the key to success.

Femoro-iliacal artery versus pulmonary artery core temperature measurement during therapeutic hypothermia: an observational study.

AIM OF THE STUDY: Therapeutic hypothermia after cardiac arrest improves neurologic outcome. The temperature measured in the pulmonary artery is considered to best reflect core temperature, yet is limited by invasiveness. Recently a femoro-arterial thermodilution catheter (PiCCO-Pulse Contour Cardiac Output) has been introduced in clinical practice as a safe and accurate haemodynamic monitoring system, which is also able to measure blood temperature. The aim of the study was to investigate, if the temperature measured with the PiCCO catheter reflects pulmonary artery temperature better than other sites during therapeutic hypothermia. METHODS: In this observational study twenty patients after cardiac arrest and successful resuscitation were cooled with various cooling methods to 33 ± 1°C for 24h, followed by rewarming. Temperatures were recorded continuously in the pulmonary artery (Tpa), femoro-iliacal artery (Tpicco), ear canal (Tear), oesophagus (Toeso) and urinary bladder (Tbla). We assessed agreement of methods using the Bland Altman approach including bias and limits of agreement (LA). RESULTS: All other sites differed significantly from Tpa with the bias varying from 0.4°C (Tbla) to -0.6°C (Tear). Standard deviations varied from 0.1°C (Tpicco, Toeso) to 0.5°C (Tear). For all sites bias was closer to zero with increasing average temperatures. Bias tended to be larger in the cooling phase compared to overall measurements. CONCLUSIONS: Temperature measurement in the femoro-iliacal artery (Tpicco) reflects the gold standard of pulmonary artery temperature most accurately, especially during the cooling phase. Tpicco is easily accessible and might be used for monitoring core temperature without the need for additional temperature probes.

Seasonal variability and influence of outdoor temperature on body temperature of cardiac arrest victims.

AIM OF THE STUDY: Mild therapeutic hypothermia is a major advance in post-resuscitation-care. Some questions remain unclear regarding the time to initiate cooling and the time to achieve target temperature below 34 °C. We examined whether seasonal variability of outside temperature influences the body temperature of cardiac arrest victims, and if this might have an effect on outcome. METHODS: Patients with witnessed out-of-hospital cardiac arrests were enrolled retrospectively. Temperature variables from 4 climatic stations in Vienna were provided from the Central Institute for Meteorology and Geodynamics. Depending on the outside temperature at the scene the study participants were assigned to a seasonal group. To compare the seasonal groups a Student's t-test or Mann-Whitney U test was performed as appropriate. RESULTS: Of 134 patients, 61 suffered their cardiac arrest during winter, with an outside temperature below 10 °C; in 39 patients the event occurred during summer, with an outside temperature above 20 °C. Comparing the tympanic temperature recorded at hospital admission, the median of 36 °C (IQR 35.3-36.3) during summer differed significantly to winter with a median of 34.9 °C (IQR 34-35.6) (p<0.05). This seasonal alterations in core body temperature had no impact on the time-to-target-temperature, survival rate or neurologic recovery. CONCLUSION: The seasonal variability of outside temperature influences body temperature of out-of-hospital cardiac arrest victims.

Randomized crossover trial comparing physical strain on advanced life support providers during transportation using real-time automated feedback.

BACKGROUND: Feedback devices provide verbal and visual real-time information on cardiopulmonary resuscitation (CPR) quality. Feedback devices can improve the quality of CPR during transportation. It remains unclear if feedback has an effect on the physical strain felt by providers during ongoing CPR. OBJECTIVES: The objective was to assess the influence of real-time automated feedback on physical strain of rescuers during ongoing chest compressions in different means of transportation. METHODS: The study was a randomized crossover trial comparing physical strain on advanced life support (ALS) providers during chest compressions using real-time automated feedback in different transport environments: 1) a moving ambulance and 2) a flying helicopter. The authors measured objective and subjective measures of physical strain and calculated the difference in the rate pressure product (RPP) after 8 minutes of external chest compressions. RESULTS: There was no difference in the RPP (mean intraindividual difference = 21; 95% confidence interval [CI] = -1,438 to 1,480; p = 0.98) between using the feedback device versus no feedback. There was no significant interaction of vehicle type on the effect of feedback on the RPP. Feedback resulted in a significant mean perceived exertion reduction of a Borg scale score by 0.89 points (95% CI = 0.42 to 1.35; p < 0.001). For systolic and diastolic blood pressure, for serum lactate concentrations, and for the modified Nine Hole Peg Test (NHPT; measurement of fine motor skills), we found no statistically significant differences. CONCLUSIONS: Feedback devices for CPR during transportation do not have an effect on objective components of physical strain, but decrease perceived exertion in experienced rescuers in an experimental setting.

Mild therapeutic hypothermia is associated with favourable outcome in patients after cardiac arrest with non-shockable rhythms.

AIM: Mild therapeutic hypothermia (32-34°C) improves neurological recovery and reduces the risk of death in comatose survivors of cardiac arrest when the initial rhythm is ventricular fibrillation or pulseless ventricular tachycardia. The aim of the presented study was to investigate the effect of mild therapeutic hypothermia (32-34°C for 24h) on neurological outcome and mortality in patients who had been successfully resuscitated from non-ventricular fibrillation cardiac arrest. METHODS: In this retrospective cohort study we included cardiac arrest survivors of 18 years of age or older suffering a witnessed out-of-hospital cardiac arrest with asystole or pulseless electric activity as the first documented rhythm. Data were collected from 1992 to 2009. Main outcome measures were neurological outcome within six month and mortality after six months. RESULTS: Three hundred and seventy-four patients were analysed. Hypothermia was induced in 135 patients. Patients who were treated with mild therapeutic hypothermia were more likely to have good neurological outcomes in comparison to patients who were not treated with hypothermia with an odds ratio of 1.84 (95% confidence interval: 1.08-3.13). In addition, the rate of mortality was significantly lower in the hypothermia group (odds ratio: 0.56; 95% confidence interval: 0.34-0.93). CONCLUSION: Treatment with mild therapeutic hypothermia at a temperature of 32-34°C for 24h is associated with improved neurological outcome and a reduced risk of death following out-of-hospital cardiac arrest with non-shockable rhythms.

Cardiac arrest survivors with moderate elevated body mass index may have a better neurological outcome: a cohort study.

AIM: Body mass index (BMI) may influence the quality of cardiopulmonary resuscitation and may influence prognosis after cardiac arrest. To review the direct effect of obesity on outcome after cardiac arrest, the following cohort study was conducted. METHODS: This study based on a cardiac arrest registry comprising all adult patients with cardiac arrest of non-traumatic origin and restoration of spontaneous circulation (ROSC) admitted to the department of emergency medicine of a tertiary-care facility. Data were collected between January 1992 and December 2007 according to the Utstein criteria. We assessed the association between BMI according to the WHO classification (underweight, BMI<18.5; normal weight, 18.5-24.9; overweight, 25.0-29.9; obese ≥ 30), six-month survival and neurological recovery. RESULTS: Analysis was carried out on a total of 1915 adult patients (32% female). Patients had a median age of 59 years (interquartile range [IQR] 49-70) and a median BMI of 26.0 (IQR 23.9-29.1). Survival to six months was 50%. There was no significant difference in survival between the BMI groups (underweight 46%, normal weight 47%, overweight 52%, obese 51%). In a multivariate analysis neurological outcome was better in overweight patients as compared to subjects with normal BMI (odds ratio 1.35; 95% confidence interval 1.02-1.79). CONCLUSION: Body mass index may have no direct influence on six-month survival after cardiac arrest, but patients with moderately elevated BMI may have a better neurological prognosis.

Exercise related cardiac arrest in amateur athletes on the tennis court.

AIM OF THE STUDY: The aim of this study was to study exercise-related cardiac arrests on the tennis court and investigate the impact of early initiation of cardiopulmonary resuscitation on survival rate and outcome. METHODS: This study was based on the cardiac arrest registry of the Department of Emergency Medicine at the General Hospital Vienna in Austria. Between February 1993 and April 2010 non-professional athletes were identified, who experienced exercise-related cardiac arrest on the tennis court. The analysis was accomplished using descriptive statistics. Results are presented as mean±standard-deviation or median and interquartile range (IQR). RESULTS: The subjects (n=27) were predominantly male (96%) with a median age of 58 years; 52% of all patients had underlying cardiovascular risk factors. All cardiac arrests were witnessed. Bystander CPR was documented in 17 cases (63%). Median time from collapse to initiation of CPR was 1(IQR 0-2) minute. Ventricular fibrillation was the initial rhythm in 25 patients (93%) and in 3 an automated external defibrillator was used by bystanders. Twenty-four patients (89%) had return of spontaneous circulation before admission to the hospital and four (15%) followed verbal commands thereafter. The survival rate at 6 months was 82% with 20 patients (74%) having favourable neurologic outcome. CONCLUSIONS: Cardiac arrest on the tennis court is a predominantly witnessed event with a respectively high rate of bystander CPR, which reflects in a high successful survival rate.

Relationship between time to target temperature and outcome in patients treated with therapeutic hypothermia after cardiac arrest.

INTRODUCTION: Our purpose was to study whether the time to target temperature correlates with neurologic outcome in patients after cardiac arrest with restoration of spontaneous circulation treated with therapeutic mild hypothermia in an academic emergency department. METHODS: Temperature data between April 1995 and June 2008 were collected from 588 patients and analyzed in a retrospective cohort study by observers blinded to outcome. The time needed to achieve an esophageal temperature of less than 34°C was recorded. Survival and neurological outcomes were determined within six months after cardiac arrest. RESULTS: The median time from restoration of spontaneous circulation to reaching a temperature of less than 34°C was 209 minutes (interquartile range [IQR]: 130-302) in patients with favorable neurological outcomes compared to 158 min (IQR: 101-230) (P < 0.01) in patients with unfavorable neurological outcomes. The adjusted odds ratio for a favorable neurological outcome with a longer time to target temperature was 1.86 (95% CI 1.03 to 3.38, P = 0.04). CONCLUSIONS: In comatose cardiac arrest patients treated with therapeutic hypothermia after return of spontaneous circulation, a faster decline in body temperature to the 34°C target appears to predict an unfavorable neurologic outcome.

Comparison of surface cooling and invasive cooling for rapid induction of mild therapeutic hypothermia in pigs--effectiveness of two different devices.

AIM OF THE STUDY: The effectiveness and safety of non-invasive surface cooling was compared to invasive endovascular cooling in an animal model. METHODS: Eight healthy pigs (29-38 kg) were cooled twice, starting in the first 4 pigs with unique surface cooling pads followed by endovascular cooling. In the second 4 pigs the order was reversed. The goal was to quickly lower pulmonary artery temperature from 38 to 33°C. A paired t-test was used to compare cooling rates (°C/h, mean±standard deviation) between both cooling techniques. RESULTS: Mean non-invasive surface cooling rate (11.9±3.8°C/h) significantly exceeded mean invasive cooling rate (3.9±0.7°C/h; p<0.001). The mean difference in cooling rates was 8.0±3.6°C/h. No surface cooling related adverse skin reactions were observed. CONCLUSIONS: Surface cooling is a simple method for achieving fast cooling rates. In our animal model, non-invasive cooling was three times faster than rapid endovascular cooling without overshoot.

Temperature monitored on the cuff surface of an endotracheal tube reflects body temperature.

OBJECTIVE: When treating patients with cardiac arrest with mild therapeutic hypothermia, a reliable and easy-to-use temperature probe is desirable. This study was conducted to investigate the accuracy and safety of tracheal temperature as a measurement of body temperature. DESIGN: Observational cohort study. SETTING: Emergency department of a tertiary care university hospital. PATIENTS: Patients successfully resuscitated from cardiac arrest intended for mild hypothermia therapy. INTERVENTIONS: Intubation was performed with a newly developed endotracheal tube that contains a temperature sensor inside the cuff surface. During the cooling, mild hypothermia maintenance, and rewarming phases, the temperature was recorded minute by minute. These data were compared with the temperature assessed by esophageal and blood temperature probes. Thereafter, tracheoscopy was performed to evaluate the condition of the tracheal mucosa. MEASUREMENTS AND MAIN RESULTS: Approximately 2000 measurements per temperature sensor per patient were recorded in 21 patients. The mean bias between the blood temperature and the tracheal temperature was -0.16 degrees C (limits of agreement: -0.36 degrees C to 0.04 degrees C). The mean bias between the esophageal and tracheal temperatures was -0.22 degrees C (limits of agreement: -0.49 degrees C to 0.07 degrees C). Agreement between temperature probes investigated by the Bland-Altman method showed a mean bias of less than -(1/4) degrees C, and time lags assessed graphically by hysteresis plots were negligible. No clinically relevant injury to the tracheal mucosa was detected. CONCLUSION: Temperature monitoring at the cuff surface of an endotracheal tube is safe and provides accurate and reliable data in all phases of therapeutically induced mild hypothermia after cardiac arrest.

Surface cooling for rapid induction of mild hypothermia after cardiac arrest: design determines efficacy.

OBJECTIVES: Recently, a novel cooling pad was developed for rapid induction of mild hypothermia after cardiac arrest. The aim of this study was to evaluate the cooling efficacy of three different pad designs for in-hospital cooling. METHODS: Included in this prospective interventional study were patients with esophageal temperature (Tes) > 34 degrees C on admission. The cooling pad consists of multiple cooling units, filled with a combination of graphite and water, which is precooled to -18 degrees C (design A) or to -9 degrees C (designs B and C) before use. The designs of the cooling pad differed in number, shape, and thickness of the cooling units, with weights of 9.7 kg (design A), 5.3 kg (design B), and 6.2 kg (design C). All three designs were tested in sequential order and were changed according to the results found in the previous trial. Cooling was started after admission until Tes = 34 degrees C, when the cooling pad was removed. The target temperature of Tes = 32-34 degrees C was maintained for 24 hours. Data are presented as medians and interquartile ranges (IQRs = 25%-75%) or proportions. RESULTS: Cooling rates were 3.4 degrees C/hour (IQR = 2.5-3.7) with design A (n = 12), 2.8 degrees C/hour (IQR = 1.6-3.3) with design B (n = 7), and 2.9 degrees C/hour (IQR = 1.9-3.6) with design C (n = 10; p = 0.5). To reach 34 degrees C, the cooling pad had to be exchanged with a new one due to melting and therefore depleting cooling capacity in three patients with design A, in five patients with design B, and in no patient with design C (p = 0.004). CONCLUSIONS: With adequate design and storage temperature, the cooling pad proved to be efficient for rapid in-hospital cooling of patients resuscitated from cardiac arrest.

Non-invasive continuous cerebral temperature monitoring in patients treated with mild therapeutic hypothermia: an observational pilot study.

AIM OF THE STUDY: To investigate if body temperature as measured with a prototype of a non-invasive continuous cerebral temperature sensor using the zero-heat-flow method to reflect the oesophageal temperature (core temperature) during mild therapeutic hypothermia after cardiac arrest. METHODS: In patients over 18 years old with restoration of spontaneous circulation after cardiac arrest, a temperature sensor that uses the zero-heat-flow principle was placed on the forehead during the periods of cooling and re-warming. This temperature was compared to oesophageal temperature as the primary temperature-monitoring site. To assess agreement, we used the Bland-Altman approach and Lin's concordance correlation coefficient. RESULTS: From September 2008 to April 2009, data from 19 patients were analysed. The median time from restoration of spontaneous circulation until temperature sensor application was 53min (interquartile range, 31; 96). All sensors were removed when a core temperature of 36 degrees C was reached. These measurements were in agreement with oesophageal temperature measurements. No allergic reaction, rash or other irritation occurred on the skin around or under the probes. Bland-Altman results showed a bias of -0.12 degrees C and 95% limits of agreement of -0.59 and +0.36 degrees C. Lin's concordance correlation coefficient was 0.98. CONCLUSIONS: Body temperature measurements using a non-invasive continuous cerebral temperature sensor prototype that uses the zero-heat-flow method accurately reflected oesophageal temperature measurements during mild therapeutic hypothermia in patients with restoration of spontaneous circulation after cardiac arrest.