Giacomo Strapazzon

Resuscitation of avalanche victims: Evidence-based guidelines of the international commission for mountain emergency medicine (ICAR MEDCOM) Intended for physicians and other advanced life support personnel

BACKGROUND In North America and Europe ∼150 persons are killed by avalanches every year. METHODS The International Commission for Mountain Emergency Medicine (ICAR MEDCOM) systematically developed evidence-based guidelines and an algorithm for the management of avalanche victims using a worksheet of 27 Population Intervention Comparator Outcome questions. Classification of recommendations and level of evidence are ranked using the American Heart Association system. RESULTS AND CONCLUSIONS If lethal injuries are excluded and the body is not frozen, the rescue strategy is governed by the duration of snow burial and, if not available, by the victims core-temperature. If burial time ≤35 min (or core-temperature ≥32 °C) rapid extrication and standard ALS is important. If burial time >35 min and core-temperature <32 °C, treatment of hypothermia including gentle extrication, full body insulation, ECG and core-temperature monitoring is recommended, and advanced airway management if appropriate. Unresponsive patients presenting with vital signs should be transported to a hospital capable of active external and minimally invasive rewarming such as forced air rewarming. Patients with cardiac instability or in cardiac arrest (with a patent airway) should be transported to a hospital for extracorporeal membrane oxygenation or cardiopulmonary bypass rewarming. Patients in cardiac arrest should receive uninterrupted CPR; with asystole, CPR may be terminated (or withheld) if a patient is lethally injured or completely frozen, the airway is blocked and duration of burial >35 min, serum potassium >12 mmol L(-1), risk to the rescuers is unacceptably high or a valid do-not-resuscitate order exists. Management should include spinal precautions and other trauma care as indicated.

LUCAS compared to manual cardiopulmonary resuscitation is more effective during helicopter rescue-a prospective, randomized, cross-over manikin study.

OBJECTIVE High-quality chest-compressions are of paramount importance for survival and good neurological outcome after cardiac arrest. However, even healthcare professionals have difficulty performing effective chest-compressions, and quality may be further reduced during transport. We compared a mechanical chest-compression device (Lund University Cardiac Assist System [LUCAS]; Jolife, Lund, Sweden) and manual chest-compressions in a simulated cardiopulmonary resuscitation scenario during helicopter rescue. METHODS Twenty-five advanced life support-certified paramedics were enrolled for this prospective, randomized, crossover study. A modified Resusci Anne manikin was employed. Thirty minutes of training was allotted to both LUCAS and manual cardiopulmonary resuscitation (CPR). Thereafter, every candidate performed the same scenario twice, once with LUCAS and once with manual CPR. The primary outcome measure was the percentage of correct chest-compressions relative to total chest-compressions. RESULTS LUCAS compared to manual chest-compressions were more frequently correct (99% vs 59%, P < .001) and were more often performed correctly regarding depth (99% vs 79%, P < .001), pressure point (100% vs 79%, P < .001) and pressure release (100% vs 97%, P = .001). Hands-off time was shorter in the LUCAS than in the manual group (46 vs 130 seconds, P < .001). Time until first defibrillation was longer in the LUCAS group (112 vs 49 seconds, P < .001). CONCLUSIONS During this simulated cardiac arrest scenario in helicopter rescue LUCAS compared to manual chest-compressions increased CPR quality and reduced hands-off time, but prolonged the time interval to the first defibrillation. Further clinical trials are warranted to confirm potential benefits of LUCAS CPR in helicopter rescue.

Ketamine: use in anesthesia.

The role of ketamine anesthesia in the prehospital, emergency department and operating theater settings is not well defined. A nonsystematic review of ketamine was performed by authors from Australia, Europe, and North America. Results were discussed among authors and the final manuscript accepted. Ketamine is a useful agent for induction of anesthesia, procedural sedation, and analgesia. Its properties are appealing in many awkward clinical scenarios. Practitioners need to be cognizant of its side effects and limitations.

Adherence of backcountry winter recreationists to avalanche prevention and safety practices in northern Italy.

Backcountry recreationists account for a high percentage of avalanche fatalities, but the total number of recreationists and relative percentage of different recreation types are unknown. The aim of this study was to collect the first comprehensive survey of backcountry skiers and snowshoers in a region in the European Alps to quantify adherence to basic prevention and safety practices. Over a 1‐week period in February 2011 in South Tyrol, Italy, 5576 individuals (77.7% skiers, 22.3% snowshoers) in 1927 groups were surveyed. Significantly more skiers than snowshoers could report the avalanche danger level (52.5% vs 28.0% of groups) and carried standard rescue equipment (transceiver, probe, and shovel) (80.6% vs 13.7% of individuals). Complete adherence to minimum advisable practices (i.e., an individual being in a group with one member correctly informed about the danger level and carrying personal standard rescue equipment) was 41.5%, but was significantly higher in skiers (51.1% vs 8.7% snowshoers) and in individuals who were younger, reported more tours per season, traveled in larger groups, and started earlier. A transnational survey over a complete winter season would be required to obtain total participation prevalence, detect regional differences, and assess the influence of prevention and safety practices on relative reduction in mortality.

Factors affecting survival from avalanche burial—A randomised prospective porcine pilot study

BACKGROUND AND AIM The majority of avalanche victims who sustain complete burial die within 35min due to asphyxia and injuries. After 35min, survival is possible only in the presence of a patent airway, and an accompanying air pocket around the face may improve survival. At this stage hypothermia is assumed to be an important factor for survival because rapid cooling decreases oxygen consumption; if deep hypothermia develops before cardiac arrest, hypothermia may be protective and prolong the time that cardiac arrest can be survived. The aim of the study was to investigate the combined effects of hypoxia, hypercapnia and hypothermia in a porcine model of avalanche burial. METHODS Eight piglets were anaesthetised, intubated and buried under snow, randomly assigned to an air pocket (n=5) or ambient air (n=3) group. RESULTS Mean cooling rates in the first 10min of burial were -19.7±4.7°Ch(-1) in the air pocket group and -13.0±4.4°Ch(-1) in the ambient air group (P=0.095); overall cooling rates between baseline and asystole were -4.7±1.4°Ch(-1) and -4.6±0.2°Ch(-1) (P=0.855), respectively. In the air pocket group cardiac output (P=0.002), arterial oxygen partial pressure (P=0.001), arterial pH (P=0.002) and time to asystole (P=0.025) were lower, while arterial carbon dioxide partial pressure (P=0.007) and serum potassium (P=0.042) were higher compared to the ambient air group. CONCLUSION Our results demonstrate that hypothermia may develop in the early phase of avalanche burial and severe asphyxia may occur even in the presence of an air pocket.

Electrical Heart Activity Recorded During Prolonged Avalanche Burial

A man in his midthirties triggered an avalanche at an elevation of 2750 m (9022 ft) while ski touring and sustained complete avalanche burial for 253 minutes before being located with an avalanche transceiver device, probed, and extricated by a rescue team. The burial depth (ie, depth of the head) was 30 cm (1 ft). The victim was in a supine position with a patent airway and a clearly visible air space in front of the mouth and nose with a size of 15×15×5 cm (0.5×0.5×0.2 ft) and frozen inner surface, which was not reported to the emergency physician on site. The victim had a Glasgow Coma Scale of 3 (E1V1M1), no vital signs, and no obvious traumatic fatal injuries. Extrication proceeded without reading the core body temperature or ECG. Because of severe weather conditions and the impending risk for the rescue team, the emergency physician withheld an on-site attempt of resuscitation. The victim was evacuated down to the valley by helicopter and declared dead. While the victims body was being handled in the mortuary, it was revealed that the victim was equipped with a multifunction sport watch and transmitter chest belt. The recorded dataset included heart rate, …

Respiratory Failure and Spontaneous Hypoglycemia During Noninvasive Rewarming From 24.7°C (76.5°F) Core Body Temperature After Prolonged Avalanche Burial

Clinical reports on management and rewarming complications after prolonged avalanche burial are not common. We present a case of an unreported combination of respiratory failure and unexpected spontaneous hypoglycemia during noninvasive rewarming from severe hypothermia. We collected anecdotal observations in a 42-year-old, previously healthy, male backcountry skier admitted to the ICU at a tertiary care center after 2 hours 7 minutes of complete avalanche burial, who presented with a patent airway and a core body temperature of 25.0°C (77.0°F) on extrication. There was no decrease in core body temperature during transport (from 25.0°C [77.0°F] to 24.7°C [76.5°F]). Atrial fibrillation occurred during active noninvasive external rewarming (to 37.0°C [98.6°F] during 5 hours), followed by pulmonary edema and respiratory failure (SaO(2) 73% and PaO(2)/FIO(2) 161 mm Hg), which resolved with endotracheal intubation and continuous positive end-respiratory pressure. Moreover, a marked spontaneous glycemic imbalance (from 22.2 to 1.4 mmol/L) was observed. Despite a possible favorable outcome, clinicians should be prepared to identify and treat severe respiratory problems and spontaneous hypoglycemia during noninvasive rewarming of severely hypothermic avalanche victims.

Basic life support trained nurses ventilate more efficiently with laryngeal mask supreme than with facemask or laryngeal tube suction-disposable—A prospective, randomized clinical trial

OBJECTIVE In some emergency situations resuscitation and ventilation may have to be performed by basic life support trained personnel, especially in rural areas where arrival of advanced life support teams can be delayed. The use of advanced airway devices such as endotracheal intubation has been deemphasized for basically-trained personnel, but it is unclear whether supraglottic airway devices are advisable over traditional mask-ventilation. METHODS In this prospective, randomized clinical single-centre trial we compared airway management and ventilation performed by nurses using facemask, laryngeal mask Supreme (LMA-S) and laryngeal tube suction-disposable (LTS-D). Basic life support trained nurses (n=20) received one-hour practical training with each device. ASA 1-2 patients scheduled for elective surgery were included (n=150). After induction of anaesthesia and neuromuscular block nurses had two 90-second attempts to manage the airway and ventilate the patient with volume-controlled ventilation. RESULTS Ventilation failed in 34% of patients with facemask, 2% with LMA-S and 22% with LTS-D (P<0.001). In patients who could be ventilated successfully mean tidal volume was 240±210 ml with facemask, 470±120 ml with LMA-S and 470±140 ml with LTS-D (P<0.001). Leak pressure was lower with LMA-S (23.3±10.8 cm H2O, 95% CI 20.2-26.4) than with LTS-D (28.9±13.9 cm·H2O, 95% CI 24.4-33.4; P=0.047). CONCLUSIONS After one hour of introductory training, nurses were able to use LMA-S more effectively than facemask and LTS-D. High ventilation failure rates with facemask and LTS-D may indicate that additional training is required to perform airway management adequately with these devices. High-level trials are needed to confirm these results in cardiac arrest patients.

Factors associated with optic nerve sheath diameter during exposure to hypobaric hypoxia

Objective: To monitor the changes in optic nerve sheath diameter (ONSD) induced by acute exposure to hypobaric hypoxia and to investigate factors associated with these changes, including development of acute mountain sickness. Methods: In this cohort study, neurologic signs and symptoms, cardiovascular parameters, and ultrasonography of ONSD were prospectively assessed in 19 healthy lowlanders at baseline and after ascent to 3,830 m (3 hours, 9 hours, 24 hours, 48 hours, 72 hours, and 8 days) by blinded investigators. Potential confounding factors (e.g., altitude variations, physical effort) were minimized. A multivariate analysis of factors associated with ONSD was performed by means of generalized estimating equations. Results: ONSD increased with exposure to altitude in all participants (p < 0.001). The increase between 9 and 24 hours was larger in patients who developed acute mountain sickness (p = 0.001). There was no influence of sex, oxygen saturation, or acclimatization on ONSD. Conclusion: Both physiologic and pathologic responses to hypobaric hypoxia were independently associated with changes in ONSD. Studies on a larger cohort, at a range of altitudes, and with baseline neuroimaging techniques are necessary to further understand the clinical significance of increased ONSD during exposure to hypobaric hypoxia.

Ultrasonography of the Optic Nerve Sheath Diameter for Diagnosis and Monitoring of Acute Mountain Sickness: A Systematic Review

AIMS Despite extensive research on acute mountain sickness (AMS), the underlying pathophysiology remains unclear. Ultrasonography studies have shown that optic nerve sheath diameter (ONSD) correlates with intracranial pressure (ICP) in critical care patients, and recent studies report elevated ONSD values at high altitude. The aim of this review was to elucidate whether 1. measurement of ONSD could shed light on the pathophysiology of AMS, and 2. ultrasonography of the ONSD could support the diagnosis of AMS. METHODS Systematic search of MEDLINE (through Pubmed; from 1966 to 14 October 2014), Cochrane Central Register of Controlled Trials (CENTRAL), and EMBASE databases. RESULTS Six studies with 436 subjects (139 women, 297 men; 406 mostly Caucasian; 30 Nepalese) were included. A marked variability in ONSD was found across studies both at baseline and at high altitude. CONCLUSION The variability in ONSD across the included studies and within each study limit the utility of ONSD measurement in the diagnosis of AMS. ONSD measurements might be useful from a population perspective, but the accuracy of optic nerve ultrasonography for single subjects and single point-in-time assessment for diagnosing AMS is questionable due to high individual variability in ONSD.