Cardiac Arrest in the Cardiac Catheterization Laboratory: Combining Mechanical Chest Compressions and Percutaneous LV Assistance.

OBJECTIVES: The aim of this study was to evaluate the optimal treatment approach for cardiac arrest (CA) occurring in the cardiac catheterization laboratory. BACKGROUND: CA can occur in the cath lab during high-risk percutaneous coronary intervention. While attempting to correct the precipitating cause of CA, several options are available to maintain vital organ perfusion. These include manual chest compressions, mechanical chest compressions, or a percutaneous left ventricular assist device. METHODS: Eighty swine (58 ± 10 kg) were studied. The left main or proximal left anterior descending artery was occluded. Ventricular fibrillation (VFCA) was induced and circulatory support was provided with 1 of 4 techniques: either manual chest compressions (frequently interrupted), mechanical chest compressions with a piston device (LUCAS-2), an Impella 2.5 L percutaneously placed LVAD, or the combination of mechanical chest compressions and the percutaneous left ventricular assist device. The study protocol included 12 min of left main coronary occlusion, reperfusion, with defibrillation attempted after 15 min of VFCA. Primary outcome was favorable neurological function (CPC 1 or 2) at 24 h, while secondary outcomes included return of spontaneous circulation and hemodynamics. RESULTS: Manual chest compressions provided fewer neurologically intact surviving animals than the combination of a mechanical chest compressor and a percutaneous LVAD device (0% vs. 56%; p < 0.01), while no difference was found between the 2 mechanical approaches (28% vs. 35%: p = 0.75). Comparing integrated coronary perfusion pressure showed sequential improvement in hemodynamic support with mechanical devices (401 ± 230 vs. 1,337 ± 905 mm Hg/s; p = 0.06). CONCLUSIONS: Combining 2 mechanical devices provided superior 24-h survival with favorable neurological recovery compared with manual compressions during moderate duration VFCA associated with an acute coronary occlusion in the animal catheterization laboratory.

Assessment of Simulated Emergency Scenarios: Are Trained Observers Necessary?

OBJECTIVES: Simulation-based medical training is associated with superior educational outcomes and improved cost efficiency. Self- and peer-assessment may be a cost-effective and flexible alternative to expert-led assessment. We compared accuracy of self- and peer-assessment of untrained raters using basic evaluation tools to expert assessment using advanced validation tools including validated questionnaires and post hoc video-based analysis. METHODS: Twenty-eight simulated emergency airway management scenarios were observed and video-recorded for further assessment. Participants consisted of 28 emergency physicians who were involved in four different airway management scenarios with different roles: One scenario as a team leader, one as an assisting team member, and two as an observer. Non-technical skills (NTS) and technical skills (TS) were analyzed by three independent groups: 1) the performing team (PT) consisted of the two emergency physicians acting either in the role of team leader or team member (self-assessment); 2) the observing team (OT), consisted of two of the participating emergency physicians not involved in the current clinical scenario (peer-assessment) and assessment occurred during (OT) or directly after (PT) the simulation without prior specific interpretational training but using standardized questionnaires; and 3) the expert team (ET) consisted of two specifically trained external observers (one psychologist and one emergency physician) using video-assisted objective assessment combined with standardized questionnaires. RESULTS: Intragroup reliability demonstrated by intra-class correlation (ICC) was moderate to good for TS (ICC 0.42*) and NTS (ICC 0.55*) in PT and moderate to good for TS (ICC 0.41*) or poor for NTS (ICC 0.27) in OT. ET showed an excellent intragroup reliability for both TS (ICC 0.78*) and NTS (ICC 0.81*). Interrater reliability was significantly different between ET and PT and between ET and OT for both TS and NTS. There was no difference between OT and PT for neither TS nor NTS; *p < 0.05. CONCLUSIONS: Expert assessment of simulation-based medical training scenarios using validated checklists and performance of post hoc video-based analysis was superior to self- or peer-assessment of untrained observers for both TS and NTS.

Importance of Both Early Reperfusion and Therapeutic Hypothermia in Limiting Myocardial Infarct Size Post-Cardiac Arrest in a Porcine Model.

OBJECTIVES: The aim of this study was to test the hypothesis that hypothermia and early reperfusion are synergistic for limiting infarct size when an acutely occluded coronary is associated with cardiac arrest. BACKGROUND: Cohort studies have shown that 1 in 4 post-cardiac arrest patients without ST-segment elevation has an acutely occluded coronary artery. However, many interventional cardiologists remain unconvinced that immediate coronary angiography is needed in these patients. METHODS: Thirty-two swine (mean weight 35 ± 5 kg) were randomly assigned to 1 of the following 4 treatment groups: group A, hypothermia and reperfusion; group B, hypothermia and no reperfusion; group C, no hypothermia and reperfusion; and group D, no hypothermia and no reperfusion. The left anterior descending coronary artery was occluded with an intracoronary balloon, and ventricular fibrillation was electrically induced. Cardiopulmonary resuscitation was begun after 4 min of cardiac arrest. Defibrillation was attempted after 2 min of cardiopulmonary resuscitation. Resuscitated animals randomized to hypothermia were rapidly cooled to 34°C, whereas those randomized to reperfusion had such after 45 min of left anterior descending coronary artery occlusion. RESULTS: At 4 h, myocardial infarct size was calculated. Group A had the smallest infarct size at 16.1 ± 19.6% (p < 0.05). Group C had an intermediate infarct size at 29.5 ± 20.2%, whereas groups B and D had the largest infarct sizes at 41.5 ± 15.5% and 41.1 ± 15.0%, respectively. CONCLUSIONS: Acute coronary occlusion is often associated with cardiac arrest, so treatment of resuscitated patients should include early coronary angiography for potential emergent reperfusion, while providing hypothermia for both brain and myocardial protection. Providing only early hypothermia, while delaying coronary angiography, is not optimal.

Prehospital risk factors of mortality and impaired consciousness after severe traumatic brain injury: an epidemiological study.

BACKGROUND: Severe traumatic brain injury (TBI) is a significant health concern and a major burden for society. The period between trauma event and hospital admission in an emergency department (ED) could be a determinant for secondary brain injury and early survival. The aim was to investigate the relationship between prehospital factors associated with secondary brain injury (arterial hypotension, hypoxemia, hypothermia) and the outcomes of mortality and impaired consciousness of survivors at 14 days. METHODS: A multicenter, prospective cohort study was performed in dedicated trauma centres of Switzerland. Adults with severe TBI (Abbreviated Injury Scale score of head region (HAIS) >3) were included. Main outcome measures were death and impaired consciousness (Glasgow Coma Scale (GCS) ≤13) at 14 days. The associations between risk factors and outcome were assessed with univariate and multivariate regression models. RESULTS: 589 patients were included, median age was 55 years (IQR 33, 70). The median GCS in ED was 4 (IQR 3-14), with abnormal pupil reaction in 167 patients (29.2%). Median ISS was 25 (IQR 21, 34). Three hundred seven patients sustained their TBI from falls (52.1%) and 190 from a road traffic accidents (32.3%). Median time from Out-of-hospital Emergency Medical Service (OHEMS) departure on scene to arrival in ED was 50 minutes (IQR 37-72); 451 patients had a direct admission (76.6%). Prehospital hypotension was observed in 24 (4.1%) patients, hypoxemia in 73 (12.6%) patients and hypothermia in 146 (24.8%). Prehospital hypotension and hypothermia (apart of age and trauma severity) was associated with mortality. Prehospital hypoxemia (apart of trauma severity) was associated with impaired consciousness; indirect admission was a protective factor. CONCLUSION: Mortality and impaired consciousness at 14 days do not have the same prehospital risk factors; prehospital hypotension and hypothermia is associated with mortality, and prehospital hypoxemia with impaired consciousness.

Prospective observational study on tracheal tube cuff pressures in emergency patients--is neglecting the problem the problem?

BACKGROUND: Inappropriately cuffed tracheal tubes can lead to inadequate ventilation or silent aspiration, or to serious tracheal damage. Cuff pressures are of particular importance during aeromedical transport as they increase due to decreased atmospheric pressure at flight level. We hypothesised, that cuff pressures are frequently too high in emergency and critically ill patients but are dependent on providers' professional background. METHODS: Tracheal cuff pressures in patients intubated before arrival of a helicopter-based rescue team were prospectively recorded during a 12-month period. Information about the method used for initial cuff pressure assessment, profession of provider and time since intubation was collected by interview during patient handover. Indications for helicopter missions were either Intensive Care Unit (ICU) transports or emergency transfers. ICU transports were between ICUs of two hospitals. Emergency transfers were either evacuation from the scene or transfer from an emergency department to a higher facility. RESULTS: This study included 101 patients scheduled for aeromedical transport. Median cuff pressure measured at handover was 45 (25.0/80.0) cmH2O; range, 8-120 cmH2O. There was no difference between patient characteristics and tracheal tube-size or whether anaesthesia personnel or non-anaesthesia personnel inflated the cuff (30 (24.8/70.0) cmH2O vs. 50 (28.0/90.0) cmH2O); p = 0.113.With regard to mission type (63 patients underwent an emergency transfer, 38 patients an ICU transport), median cuff pressure was different: 58 (30.0/100.0) cmH2O in emergency transfers vs. 30 (20.0/45.8) cmH2O in inter-ICU transports; p < 0.001. For cuff pressure assessment by the intubating team, a manometer had been applied in 2 of 59 emergency transfers and in 20 of 34 inter-ICU transports (method was unknown for 4 cases each). If a manometer was used, median cuff pressure was 27 (20.0/30.0) cmH2O, if not 70 (47.3/102.8) cmH2O; p < 0.001. CONCLUSIONS: Cuff pressures in the pre-hospital setting and in intensive care units are often too high. Interestingly, there is no significant difference between non-anaesthesia and anaesthesia personnel. Acceptable cuff pressures are best achieved when a cuff pressure manometer has been used. This method seems to be the only feasible one and is recommended for general use.

Role of manual and mechanical chest compressions during resuscitation efforts throughout cardiac arrest.

The previously published randomized trials of mechanical versus manual resuscitation of patients with cardiac arrest are inconclusive, but a recent systematic review concluded: "There is no evidence that mechanical cardiopulmonary resuscitation devices improve survival; to the contrary they may worsen neurological outcome." However, in our view, none of the randomized trials to date are definitive as the manual groups with primary cardiac arrest have not been treated optimally; that is, with minimally interrupted manual chest compressions, as advocated with cardiocerebral resuscitation. Since the mechanical chest compression devices work on different principles, it is possible that, while they may not be as effective and may even be worse in some subsets of patients, they may be preferable in others. Nevertheless, there are situations where manual chest compressions are not practical and, in these, mechanical devices may well be preferable. The Thumper® (Michigan Instruments, MI, USA) and the LUCAS™ (Jolife AB, Lund, Sweden) devices produce sternal compressions at 100 per min. By contrast, the AutoPulse® (ZOLL Circulation, CA, USA) produces chest compressions at a rate of only 80 per min. Since chest compression rate, as reviewed in this article, is important, one would guess that the devices that can produce a faster rate would be more effective. On the other hand, it could be that sternal compressions with manual or mechanical devices may be more or less effective depending on the arrested patient's chest configuration. We speculate that in the subset of patients with barrel chests, where sternal compressions are less likely to be operative, the AutoPulse might be more effective, but less effective in thin-chested individuals, where direct cardiac compression is the major mechanism of forward blood flow in the manual, Thumper and LUCAS methods. The original LUCAS device had the potential of active decompression as well as compression. To market in the USA, holes had to be placed in the 'suction cup'. It would be informative to know whether the original LUCAS device is more effective than the device in which the active decompression has been deactivated.

Air transfer of patients with intraaortic balloon pump support: Swiss experience and recommendations.

BACKGROUND AND AIM: Inter-hospital transfers are high-risk operations for critically ill patients dependent on intra-aortic balloon pump (IABP) support. Since September 2008, Swiss Air-Rescue (Rega) has offered such transfers by helicopter. The aim of the present study was to review the first 38 IABP transfers and to promulgate the currently used standard operating procedure (SOP). METHODS: All helicopter transfers of IABP-dependent patients by Swiss Air-Rescue (Rega) between September 2008 and October 2010 were retrospectively analysed. Adverse events (e.g., death), vital parameters and respiratory modus during takeover by the Rega crew and discharge at the receiving hospital, as well as patient demographics, aetiology of heart failure and outcome at the receiving hospital were assessed. RESULTS: A total of 38 IABP transfers occurred, 35 of which were carried out to hospitals within Switzerland. No major adverse events were observed during flight. The mean patient age was 64 ± 11 (mean ± SD) years. The leading cause for IABP support was ischaemic heart failure (32 patients, 84%). The outcome of 35 patients was available: 30 were discharged home or to another institution, and 5 died at the receiving hospital. CONCLUSIONS: Based on these findings, the helicopter transport, the equipment provided, the crew composition and the predefined process offer a safe concept for these complex transfers. The adherence to standard operating procedures is a precondition to achieve excellent quality of care, facilitating and accelerating the hand-over and comprehensive care of such high-risk patients.

A sternal accelerometer does not impair hemodynamics during piglet CPR.

AIM: To determine whether the residual weight of a 260 g sternal accelerometer/force feedback device (AFFD) adversely affects hemodynamics during cardiopulmonary resuscitation in a piglet model of ventricular fibrillation cardiac arrest. METHODS: After induction of ventricular fibrillation, cardiopulmonary resuscitation was provided to ten piglets (10.8 ± 1.9 kg) for 12 min while maintaining aortic systolic pressure of 80-90 mm Hg during four 3-min periods with or without an AFFD on the chest. Cardiac output and left ventricular myocardial blood flow were determined by neutron-microsphere technique. RESULTS: Using a linear mixed-effect model with residual maximum likelihood estimation to control for changes in cardiopulmonary resuscitation hemodynamics over time, cardiac output and myocardial blood flow did not differ with AFFD versus without AFFD. During the first 6 min, mean (± SEM) cardiac outputs were 0.42 (± 0.05)L/min with AFFD versus 0.31 (± 0.04)L/min without AFFD, and median left ventricular myocardial blood flows were 40.5 (± 7.3)mL/min/100g with AFFD versus 40.4 (± 5.0)mL/min/100g without AFFD. The mean right atrial diastolic pressures and coronary perfusion pressures were also not different (8 ± 0.7 mm Hg versus 8 ± 0.9 mm Hg and 16 ± 2 mm Hg versus 16 ± 2 mm Hg, respectively, during the first 6 min of CPR). CONCLUSION: The use of a 260 g accelerometer/force feedback device designed for real-time feedback to the rescuer during resuscitation efforts did not adversely affect cardiac output or left ventricular myocardial blood flow during 12 min of chest compressions in a piglet model of ventricular fibrillation cardiac arrest.

Epinephrine improves 24-hour survival in a swine model of prolonged ventricular fibrillation demonstrating that early intraosseous is superior to delayed intravenous administration.

BACKGROUND: Vasopressors administered IV late during resuscitation efforts fail to improve survival. Intraosseous (IO) access can provide a route for earlier administration. We hypothesized that IO epinephrine after 1 minute of cardiopulmonary resuscitation (CPR) (an "optimal" IO scenario) after 10 minutes of untreated ventricular fibrillation (VF) cardiac arrest would improve outcome in comparison with either IV epinephrine after 8 minutes of CPR (a "realistic" IV scenario) or placebo controls with no epinephrine. METHODS: Thirty swine were randomized to IO epinephrine, IV epinephrine, or placebo. Important outcomes included return of spontaneous circulation (ROSC), 24-hour survival, and 24-hour survival with good neurological outcome (cerebral performance category 1). RESULTS: ROSC after 10 minutes of untreated VF was uncommon without administration of epinephrine (1 of 10), whereas ROSC was nearly universal with IO epinephrine or delayed IV epinephrine (10 of 10 and 9 of 10, respectively; P = 0.001 for either versus placebo). Twenty-four hour survival was substantially more likely after IO epinephrine than after delayed IV epinephrine (10 of 10 vs. 4 of 10, P = 0.001). None of the placebo group survived at 24 hours. Survival with good neurological outcome was more likely after IO epinephrine than after placebo (6 of 10 vs. 0 of 10, P = 0.011), and only 3 of 10 survived with good neurological outcome in the delayed IV epinephrine group (not significant versus either IO or placebo). CONCLUSION: In this swine model of prolonged VF cardiac arrest, epinephrine administration during CPR improved outcomes. In addition, early IO epinephrine improved outcomes in comparison with delayed IV epinephrine.

Post-resuscitation myocardial microcirculatory dysfunction is ameliorated with eptifibatide.

BACKGROUND: The post-cardiac arrest syndrome includes a decline in myocardial microcirculation function. Inhibition of the platelet IIb/IIIa glycoprotein receptor has improved myocardial microvascular function post-percutaneous coronary intervention. Therefore, we evaluated such inhibition with eptifibatide for its effect on myocardial microcirculation function post-cardiac arrest and resuscitation. METHODS: Four groups of swine were studied in a prospective, randomized, blinded, placebo-controlled protocol including; eptifibatide administered during CPR (Group 1, n=5), after resuscitation (Group 2, n=4), during and after resuscitation (Group 3, n=5), or placebo (Group 4, n=10). CPR was initiated following 12min of untreated VF. Those successfully resuscitated were studied during a 4-h post-resuscitation period. Coronary flow reserve, a measure of microcirculation function (in the absence of coronary obstruction), as well as parameters of left ventricular systolic and diastolic function, were measured pre-arrest and serially post-resuscitation. RESULTS: Coronary flow reserve was preserved during the post-resuscitation period, indicating normal microcirculatory function in the eptifibatide-treated animals, but not in the placebo-treated group. However, LV function declined equally in both groups during the first 4h after cardiac arrest. CONCLUSION: Inhibition of platelet IIb/IIIa glycoprotein receptors with eptifibatide post-resuscitation prevented myocardial microcirculation dysfunction. Left ventricular dysfunction post-resuscitation was not improved with eptifibatide, and perhaps transiently worse at 30min post-resuscitation. Post-cardiac arrest ventricular dysfunction may require a multi-modality treatment strategy for successful prevention or amelioration.

Prevalence and hemodynamic effects of leaning during CPR.

BACKGROUND: Cardiopulmonary resuscitation (CPR) guidelines recommend complete release between chest compressions (CC). OBJECTIVE: Evaluate the hemodynamic effects of leaning (incomplete chest wall release) during CPR and the prevalence of leaning during CPR. RESULTS: In piglet ventricular fibrillation cardiac arrests, 10% and 20% (1.8 kg and 3.6 kg, respectively), leaning during CPR increased right atrial pressures, decreased coronary perfusion pressures, and decreased cardiac index and left ventricular myocardial blood flow by nearly 50%. In contrast, residual leaning of a 260 g accelerometer/force feedback device did not adversely affect cardiac index or myocardial blood flow. Among 108 adult in-hospital CPR events, leaning ≥ 2.5 kg was demonstrable in 91% of the events and 12% of the evaluated CC. For 12 children with in-hospital CPR, 28% of CC had residual leaning ≥ 2.5 kg and 89% had residual leaning ≥ 0.5 kg. CONCLUSIONS: Leaning during CPR increases intrathoracic pressure, decreases coronary perfusion pressure, and decreases cardiac output and myocardial blood flow. Leaning is common during CPR.

Gasping in response to basic resuscitation efforts: observation in a Swine model of cardiac arrest.

Objective. To analyze the effect of basic resuscitation efforts on gasping and of gasping on survival. Methods. This is secondary analysis of a previously reported study comparing continuous chest compressions (CCC CPR) versus chest compressions plus ventilation (30:2 CPR) on survival. 64 swine were randomized to 1 of these 2 basic CPR approaches after either short (3 or 4 minutes) or long (5 or 6 minutes) durations of untreated VF. At 12 minutes of VF, all received the same Guidelines 2005 Advanced Cardiac Life Support. Neurologically status was evaluated at 24 hours. A score of 1 is normal, 2 is abnormal, such as not eating or drinking normally, unsteady gait, or slight resistance to restraint, 3 severely abnormal, where the animal is recumbent and unable to stand, 4 is comatose, and 5 is dead. For this analysis a neurological outcome score of 1 or 2 was classified as "good", and a score of 3, 4, or 5 was classified as "poor." Results. Gasping was more likely to continue or if absent, to resume in the animals with short durations of untreated VF before basic resuscitation efforts. With long durations of untreated VF, the frequency of gasping and survival was better in swine receiving CCC CPR. In the absence of frequent gasping, intact survival was rare in the long duration of untreated VF group. Conclusions. Gasping is an important phenomenon during basic resuscitation efforts for VF arrest and in this model was more frequent with CCC-CPR.

Predictors of resuscitation in a swine model of ischemic and nonischemic ventricular fibrillation cardiac arrest: superiority of amplitude spectral area and slope to predict a return of spontaneous circulation when resuscitation efforts are prolonged.

OBJECTIVE: We have demonstrated that a return of spontaneous circulation in the first 3 mins of resuscitation in swine is predicted by ventricular fibrillation waveform (amplitude spectral area or slope) when untreated ventricular fibrillation duration or presence of acute myocardial infarction is unknown. We hypothesized that in prolonged resuscitation efforts that return of spontaneous circulation immediately after a second or later shock with postshock chest compression is independently predicted by end-tidal CO2, coronary perfusion pressure, and ventricular fibrillation waveform measured before that shock in a swine model of ischemic and nonischemic ventricular fibrillation arrest. DESIGN: Animal intervention study with comparison to a control group. SETTING: University animal laboratory. SUBJECTS: Twenty swine. INTERVENTIONS: Myocardial infarction was induced by steel plug occlusion of the left anterior descending coronary artery. Ventricular fibrillation was untreated for 8 mins in normal swine (n=10) and acute myocardial infarction swine (n=10). MEASUREMENTS AND MAIN RESULTS: End-tidal CO2, coronary perfusion pressure, and ventricular fibrillation waveform characteristics of amplitude spectral area and slope were analyzed before second or later shocks. For an amplitude spectral area>35 mV-Hz, the odds ratio for achieving return of spontaneous circulation after that shock was 72 (95% confidence interval, 3.8-1300; p=.004) compared with an amplitude spectral area<28 mV-Hz and with an area under the receiver operator characteristic curve of 0.86. For slope>3.6 mV/s, the odds ratio for achieving return of spontaneous circulation was 36 (95% confidence interval, 2.7-480; p=.007) compared with slope<2.72 mV/s with an area under the curve of 0.86. End-tidal CO2 and coronary perfusion pressure were not predictive of return of spontaneous circulation after a shock, although coronary perfusion pressure was significantly related to both amplitude spectral area (p<.001) and slope (p<.001). CONCLUSIONS: : In prolonged untreated ventricular fibrillation arrest, the waveform characteristics of amplitude spectral area and slope predict the attainment of return of spontaneous circulation with a second or later shock. This has implications for the ideal means to customize the timing of shocks and chest compressions when return of spontaneous circulation is not promptly obtained.

Continued breathing followed by gasping or apnea in a swine model of ventricular fibrillation cardiac arrest.

BACKGROUND: Continued breathing following ventricular fibrillation has here-to-fore not been described. METHODS: We analyzed the spontaneous ventilatory activity during the first several minutes of ventricular fibrillation (VF) in our isoflurane anesthesized swine model of out-of-hospital cardiac arrest. The frequency and type of ventilatory activity was monitored by pneumotachometer and main stream infrared capnometer and analyzed in 61 swine during the first 3 to 6 minutes of untreated VF. RESULTS: During the first minute of VF, the air flow pattern in all 61 swine was similar to those recorded during regular spontaneous breathing during anesthesia and was clearly different from the patterns of gasping. The average rate of continued breathing during the first minute of untreated VF was 10 breaths per minute. During the second minute of untreated VF, spontaneous breathing activity either stopped or became typical of gasping. During minutes 2 to 5 of untreated VF, most animals exhibited very slow spontaneous ventilatory activity with a pattern typical of gasping; and the pattern of gasping was crescendo-decrescendo, as has been previously reported. In the absence of therapy, all ventilatory activity stopped 6 minutes after VF cardiac arrest. CONCLUSION: In our swine model of VF cardiac arrest, we documented that normal breathing continued for the first minute following cardiac arrest.

Endotracheal tube intracuff pressure during helicopter transport.

STUDY OBJECTIVE: We evaluate changes in endotracheal tube intracuff pressures among intubated patients during aeromedical transport. We determine whether intracuff pressures exceed 30 cm H(2)O during aeromedical transport. METHODS: During a 12-month period, a helicopter-based rescue team prospectively recorded intracuff pressures of mechanically ventilated patients before takeoff and as soon as the maximum flight level was reached. With a commercially available pressure manometer, intracuff pressure was adjusted to < or =25 cm H(2)O before loading of the patient. The endpoint of our investigation was the increase of endotracheal tube cuff pressure during helicopter transport. RESULTS: Among 114 intubated patients, mean altitude increase was 2,260 feet (95% confidence interval [CI] 2,040 to 2,481 feet; median 2,085 feet; interquartile range [IQR] 1,477.5 to 2,900 feet). Mean flight time was 14.8 minutes (95% CI 13.1 to 16.4 minutes; median 13.5 minutes; IQR 10 to 16.1 minutes). Intracuff pressure increased from 28.7 cm H(2)O (95% CI 27.0 to 30.4 cm H(2)O [median 25 cm H(2)O; IQR 25 to 30 cm H(2)O]) to 62.6 cm H(2)O (95% CI 58.8 to 66.5 cm H(2)O; median 58; IQR 48 to 72 cm H(2)O). At cruising altitude, 98% of patients had intracuff pressures > or =30 cm H(2)O, 72% had intracuff pressures > or =50 cm H(2)O, and 20% even had intracuff pressures > or =80 cm H(2)O. CONCLUSION: Endotracheal cuff pressure during transport frequently exceeded 30 cm H(2)O during aeromedical transport. Hospital and out-of-hospital practitioners should measure and adjust endotracheal cuff pressures before and during flight.

Mass casualty incidents with multiple burn victims: rationale for a Swiss burn plan.

INTRODUCTION: Mass casualty incidents involving victims with severe burns pose difficult and unique problems for both rescue teams and hospitals. This paper presents an analysis of the published reports with the aim of proposing a rational model for burn rescue and hospital referral for Switzerland. METHODS: Literature review including systematic searches of PubMed/Medline, reference textbooks and journals as well as landmark articles. RESULTS: Since hospitals have limited surge capacities in the event of burn disasters, a special approach to both prehospital and hospital management of these victims is required. Specialized rescue and care can be adequately met and at all levels of needs by deploying mobile burn teams to the scene. These burn teams can bring needed skills and enhance the efficiency of the classical disaster response teams. Burn teams assist with both primary and secondary triage, contribute to initial patient management and offer advice to non-specialized designated hospitals that provide acute care for burn patients with Total Burn Surface Area (TBSA) <20-30%. The main components required for successful deployments of mobile burn teams include socio-economic feasibility, streamlined logistical implementation as well as partnership coordination with other agencies including subsidiary military resources. CONCLUSIONS: Disaster preparedness plans involving burn specialists dispatched from a referral burn center can upgrade and significantly improve prehospital rescue outcome, initial resuscitation care and help prevent an overload to hospital surge capacities in case of multiple burn victims. This is the rationale behind the ongoing development and implementation of the Swiss burn plan.

Continuous chest compression resuscitation in arrested swine with upper airway inspiratory obstruction.

BACKGROUND: This study was designed to compare 24-h survival rates and neurological function of swine in cardiac arrest treated with one of three forms of simulated basic life support CPR. METHODS: Thirty swine were randomized equally among three experimental groups to receive either 30:2 CPR with an unobstructed endotracheal tube (ET) or continuous chest compression (CCC) CPR with an unobstructed ET or CCC CPR with a collapsable rubber sleeve on the ET allowing air outflow but completely restricting air inflow. The swine were anesthetized but not paralyzed. Two min of untreated VF was followed by 9 min of simulated single rescuer bystander CPR. In the 30:2 CPR group, each set of 30 chest compressions was followed by a 15-s pause to simulate the realistic duration of interrupted chest compressions required for a single rescuer to deliver 2 mouth-to-mouth ventilations. The other two groups were provided continuous chest compressions (CCC) without assisted ventilations. At 11 min post-arrest a biphasic defibrillation shock (150 J) was administered followed by a period of advanced cardiac life support. RESULTS: In the 30:2 group, 8 of 10 animals had good neurological function at 24-h post-resuscitation. In the CCC open airway group, 10 of 10, and in the CCC inspiratory obstructed group, 9 of 10. The number of shocks (P<0.05) and epinephrine doses (P<0.05) required for ROSC was greater in the 30:2 CPR group than in the other two groups. CONCLUSIONS: There were no differences in 24-h survival with good neurological function among these three different CPR protocols.

Leaning during chest compressions impairs cardiac output and left ventricular myocardial blood flow in piglet cardiac arrest.

OBJECTIVE: Complete recoil of the chest wall between chest compressions during cardiopulmonary resuscitation is recommended, because incomplete chest wall recoil from leaning may decrease venous return and thereby decrease blood flow. We evaluated the hemodynamic effect of 10% or 20% lean during piglet cardiopulmonary resuscitation. DESIGN: Prospective, sequential, controlled experimental animal investigation. SETTING: University research laboratory. SUBJECTS: Domestic piglets. INTERVENTIONS: After induction of ventricular fibrillation, cardiopulmonary resuscitation was provided to ten piglets (10.7 +/- 1.2 kg) for 18 mins as six 3-min epochs with no lean, 10% lean, or 20% lean to maintain aortic systolic pressure of 80-90 mm Hg. Because the mean force to attain 80-90 mm Hg was 18 kg in preliminary studies, the equivalent of 10% and 20% lean was provided by use of 1.8- and 3.6-kg weights on the chest. MEASUREMENTS AND MAIN RESULTS: Using a linear mixed-effect regression model to control for changes in cardiopulmonary resuscitation hemodynamics over time, mean right atrial diastolic pressure was 9 +/- 0.6 mm Hg with no lean, 10 +/- 0.3 mm Hg with 10% lean (p < .01), and 13 +/- 0.3 mm Hg with 20% lean (p < .01), resulting in decreased coronary perfusion pressure with leaning. Microsphere-determined cardiac index and left ventricular myocardial blood flow were lower with 10% and 20% leaning throughout the 18 mins of cardiopulmonary resuscitation. Mean cardiac index decreased from 1.9 +/- 0.2 L . M . min with no leaning to 1.6 +/- 0.1 L . M . min with 10% leaning, and 1.4 +/- 0.2 L . M . min with 20% leaning (p < .05). The myocardial blood flow decreased from 39 +/- 7 mL . min . 100 g with no lean to 30 +/- 6 mL . min . 100 g with 10% leaning and 26 +/- 6 mL . min . 100 g with 20% leaning (p < .05). CONCLUSIONS: Leaning of 10% to 20% (i.e., 1.8-3.6 kg) during cardiopulmonary resuscitation substantially decreased coronary perfusion pressure, cardiac index, and myocardial blood flow.

Predictors of resuscitation outcome in a swine model of VF cardiac arrest: A comparison of VF duration, presence of acute myocardial infarction and VF waveform.

INTRODUCTION: Factors that affect resuscitation to a perfusing rhythm (ROSC) following ventricular fibrillation (VF) include untreated VF duration, acute myocardial infarction (AMI), and possibly factors reflected in the VF waveform. We hypothesized that resuscitation of VF to ROSC within 3min is predicted by the VF waveform, independent of untreated VF duration or presence of acute MI. METHODS: AMI was induced by the occlusion of the left anterior descending coronary artery. VF was induced in normal (N=30) and AMI swine (N=30). Animals were resuscitated after untreated VF of brief (2min) or prolonged (8min) duration. VF waveform was analyzed before the first shock to compute the amplitude-spectral area (AMSA) and slope. RESULTS: Unadjusted predictors of ROSC within 3min included untreated VF duration (8min vs 2min; OR 0.11, 95%CI 0.02-0.54), AMI (AMI vs normal; OR 0.11, 95%CI 0.02-0.54), AMSA (highest to lowest tertile; OR 15.5, 95%CI 1.7-140), and slope (highest to lowest tertile; OR 12.7, 95%CI 1.4-114). On multivariate regression, untreated VF duration (P=0.011) and AMI (P=0.003) predicted ROSC within 3min. Among secondary outcome variables, favorable neurological status at 24h was only predicted by VF duration (OR 0.22, 95% CI 0.05-0.92). CONCLUSIONS: In this swine model of VF, untreated VF duration and AMI were independent predictors of ROSC following VF cardiac arrest. AMSA and slope predicted ROSC when VF duration or the presence of AMI were unknown. Importantly, the initial treatment of choice for short duration VF is defibrillation regardless of VF waveform.