Paal P, Brugger H, Strapazzon G.
Accidental hypothermia.
Handb Clin Neurol. 2018;157:547-563. doi: 10.1016/B978-0-444-64074-1.00033-1.
Abstract/Text
Accidental hypothermia causes profound changes to the body's physiology. After an initial burst of agitation (e.g., 36-37°C), vital functions will slow down with further cooling, until they vanish (e.g. <20-25°C). Thus, a deeply hypothermic person may appear dead, but may still be able to be resuscitated if treated correctly. The hospital use of minimally invasive rewarming for nonarrested, otherwise healthy patients with primary hypothermia and stable vital signs has the potential to substantially decrease morbidity and mortality for these patients. Extracorporeal life support (ECLS) has revolutionized the management of hypothermic cardiac arrest, with survival rates approaching 100%. Hypothermic patients with risk factors for imminent cardiac arrest (i.e., temperature <28°C, ventricular arrhythmia, systolic blood pressure <90 mmHg), and those who have already arrested, should be transferred directly to an ECLS center. Cardiac arrest patients should receive continuous cardiopulmonary resuscitation (CPR) during transfer. If prolonged transport is required or terrain is difficult, mechanic CPR can be helpful. Intermittent CPR may be appropriate in hypothermic arrest when continuous CPR is impossible. Modern postresuscitation care should be implemented following hypothermic arrest. Structured protocols should be in place to optimize prehospital triage, transport, and treatment as well as in-hospital management, including detailed criteria and protocols for the use of ECLS and postresuscitation care.
Copyright © 2018 Elsevier B.V. All rights reserved.
Paal P, Gordon L, Strapazzon G, Brodmann Maeder M, Putzer G, Walpoth B, Wanscher M, Brown D, Holzer M, Broessner G, Brugger H.
Accidental hypothermia-an update : The content of this review is endorsed by the International Commission for Mountain Emergency Medicine (ICAR MEDCOM).
Scand J Trauma Resusc Emerg Med. 2016 Sep 15;24(1):111. doi: 10.1186/s13049-016-0303-7. Epub 2016 Sep 15.
Abstract/Text
BACKGROUND: This paper provides an up-to-date review of the management and outcome of accidental hypothermia patients with and without cardiac arrest.
METHODS: The authors reviewed the relevant literature in their specialist field. Summaries were merged, discussed and approved to produce this narrative review.
RESULTS: The hospital use of minimally-invasive rewarming for non-arrested, otherwise healthy, patients with primary hypothermia and stable vital signs has the potential to substantially decrease morbidity and mortality for these patients. Extracorporeal life support (ECLS) has revolutionised the management of hypothermic cardiac arrest, with survival rates approaching 100 % in some cases. Hypothermic patients with risk factors for imminent cardiac arrest (temperature <28 °C, ventricular arrhythmia, systolic blood pressure <90 mmHg), and those who have already arrested, should be transferred directly to an ECLS-centre. Cardiac arrest patients should receive continuous cardiopulmonary resuscitation (CPR) during transfer. If prolonged transport is required or terrain is difficult, mechanical CPR can be helpful. Delayed or intermittent CPR may be appropriate in hypothermic arrest when continuous CPR is impossible. Modern post-resuscitation care should be implemented following hypothermic arrest. Structured protocols should be in place to optimise pre-hospital triage, transport and treatment as well as in-hospital management, including detailed criteria and protocols for the use of ECLS and post-resuscitation care.
CONCLUSIONS: Based on new evidence, additional clinical experience and clearer management guidelines and documentation, the treatment of accidental hypothermia has been refined. ECLS has substantially improved survival and is the treatment of choice in the patient with unstable circulation or cardiac arrest.
Matsuyama T, Morita S, Ehara N, Miyamae N, Okada Y, Jo T, Sumida Y, Okada N, Watanabe M, Nozawa M, Tsuruoka A, Fujimoto Y, Okumura Y, Kitamura T, Ohta B.
Characteristics and outcomes of accidental hypothermia in Japan: the J-Point registry.
Emerg Med J. 2018 Nov;35(11):659-666. doi: 10.1136/emermed-2017-207238. Epub 2018 Jun 9.
Abstract/Text
BACKGROUND: Accidental hypothermia (AH) has higher incidence and mortality in geriatric populations. Japan has a rapidly ageing population, and little is known about the epidemiology of hypothermia in this country.
METHODS: We created an AH registry based on retrospective review of patients visiting the ED of 12 institutions with temperature ≤35°C between April 2011 and March 2016. The severity of AH was classified as mild (≤35, ≥32°C), moderate (<32, ≥28°C) or severe (<28°C). The relationship between in-hospital mortality and severity of AH was assessed using a multivariable logistic regression analysis.
RESULTS: A total of 572 patients were registered in this registry and 537 patients were eligible for our analysis. The median age was 79 (IQR 66-87) years and the proportion of men was 51.2% (273/537). AH was more likely to occur in elderly patients aged ≥65 years (424/537, 80.0%) and in indoor settings (418/537, 77.8%). The condition most frequently associated with AH, irrespective of severity, was acute medical illness. A lower mean outside temperature was associated with a higher prevalence of AH, and particularly severe AH (p for trend <0.001). The overall proportion of cases resulting in in-hospital death was 24.4% (131/537), with no significant difference between severity levels observed in a multivariable logistic regression analysis (severe group (37/118, 31.4%) vs mild group (42/192, 21.9%), adjusted OR (AOR) 1.01, 95% CI 0.61 to 1.68; and moderate group (52/227, 22.9%) vs mild group, AOR 1.11, 95% CI 0.58 to 2.14).
CONCLUSION: Active prevention and intervention should occur for this important public health issue.
© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
Elbaz G, Etzion O, Delgado J, Porath A, Talmor D, Novack V.
Hypothermia in a desert climate: severity score and mortality prediction.
Am J Emerg Med. 2008 Jul;26(6):683-8. doi: 10.1016/j.ajem.2007.10.016.
Abstract/Text
INTRODUCTION: The goal of our study was to characterize patients admitted to the hospital with hypothermia in a desert climate.
METHODS: This was a retrospective study (1999-2005) in a 1200-bed tertiary care hospital in southern Israel. Patients' data and weather condition (including mean day high and low temperatures, humidity, wind velocity and precipitation) within 48 hours before admission were assessed.
RESULTS: One hundred sixty-nine patients with hypothermia were admitted. The mean highest environmental temperature over 48 hours before admission was 15.3 degrees C in the severe hypothermia (9 cases, 5.3%), 21.4 degrees C in the moderate (40 cases, 23.7%), and 29.3 degrees C in the mild group (120 cases, 71.0%). Major medical conditions associated with decreased body temperature were sepsis (65, 38.5%), trauma (34, 20.1%), endocrine disorders (19, 11.2%), and substance abuse (15, 8.9%). The inhospital mortality rate was 47.3%. A risk score based on 5 admission variables (age > or = 70 years, mean arterial pressure < 90 mm Hg, pH < 7.35, creatinine > 1.5 mg/dL, and confusion) was generated, predicting inhospital mortality with area under the receiver operating characteristic (ROC) curve of 0.81 (95% confidence interval, 0.75-0.87).
CONCLUSIONS: Hypothermia should not be overlooked in geographical areas with temperate climates. Using a prognostication system based upon clinical and laboratory variables may identify hypothermia patients with increased risk of death.
Brändström H, Johansson G, Giesbrecht GG, Ängquist KA, Haney MF.
Accidental cold-related injury leading to hospitalization in northern Sweden: an eight-year retrospective analysis.
Scand J Trauma Resusc Emerg Med. 2014 Jan 27;22:6. doi: 10.1186/1757-7241-22-6. Epub 2014 Jan 27.
Abstract/Text
BACKGROUND: Cold injuries are rare but important causes of hospitalization. We aimed to identify the magnitude of cold injury hospitalization, and assess causes, associated factors and treatment routines in a subarctic region.
METHODS: In this retrospective analysis of hospital records from the 4 northernmost counties in Sweden, cases from 2000-2007 were identified from the hospital registry by diagnosis codes for accidental hypothermia, frostbite, and cold-water drowning. Results were analyzed for pre-hospital site events, clinical events in-hospital, and complications observed with mild (temperature 34.9 - 32°C), moderate (31.9 - 28°C) and severe (<28°C), hypothermia as well as for frostbite and cold-water drowning.
RESULTS: From the 362 cases, average annual incidences for hypothermia, frostbite, and cold-water drowning were estimated to be 3.4/100,000, 1.5/100,000, and 0.8/100,000 inhabitants, respectively. Annual frequencies for hypothermia hospitalizations increased by approximately 3 cases/year during the study period. Twenty percent of the hypothermia cases were mild, 40% moderate, and 24% severe. For 12%, the lowest documented core temperature was 35°C or higher, for 4% there was no temperature documented. Body core temperature was seldom measured in pre-hospital locations. Of 362 cold injury admissions, 17 (5%) died in hospital related to their injuries. Associated co-factors and co-morbidities included ethanol consumption, dementia, and psychiatric diagnosis.
CONCLUSIONS: The incidence of accidental hypothermia seems to be increasing in this studied sub-arctic region. Likely associated factors are recognized (ethanol intake, dementia, and psychiatric diagnosis).
Herity B, Daly L, Bourke GJ, Horgan JM.
Hypothermia and mortality and morbidity. An epidemiological analysis.
J Epidemiol Community Health. 1991 Mar;45(1):19-23. doi: 10.1136/jech.45.1.19.
Abstract/Text
STUDY OBJECTIVE: The aim was to identify socioeconomic variables associated with deaths and hospital admissions due to hypothermia and to quantify the risk due to ambient outside temperature.
DESIGN: The study was a survey of deaths and hospital admissions due to hypothermia (ICD 991.6), for the period 1979-85 inclusive, identified from death certificates and Hospital Inpatient Enquiry (HIPE) data.
SETTING: The study included all deaths and hospital admissions due to hypothermia (1979-85) in the 26 counties of the Republic of Ireland, population 3.5 million.
SUBJECTS: All deaths coded during the study period as being due to hypothermia and all persons admitted to hospital during the study period for whom hypothermia was recorded as a discharge diagnosis in HIPE data.
MEASUREMENTS AND MAIN RESULTS: Demographic data and date of death/diagnosis were obtained from both data sets. Complete national temperature records were obtained from the meteorological service and a temperature was assigned to each case representing ambient outside temperature at which hypothermia developed. Risk of hypothermia at a given temperature was obtained by dividing the number of cases at that temperature by the appropriate person-years of exposure of the entire national population. Incidence of and mortality from hypothermia doubled with each 5 degrees C and 4 degrees C fall in temperature respectively; the majority of deaths and hospital admissions occurred between October and March. Incidence and mortality increased with age and men had 30% higher case fatality than women. Single men had four times the incidence and 6.5 times the mortality, and single women had double the incidence and four times the mortality of married men and women respectively. Low population density was also an important risk marker.
CONCLUSIONS: The risk of hypothermia due to ambient outside temperature has been quantified and a high risk group was identified. A combination of statutory support measures and good neighbourliness could prevent illness and deaths from hypothermia.
Taylor NA, Griffiths RF, Cotter JD.
Epidemiology of hypothermia: fatalities and hospitalisations in New Zealand.
Aust N Z J Med. 1994 Dec;24(6):705-10. doi: 10.1111/j.1445-5994.1994.tb01788.x.
Abstract/Text
BACKGROUND: Hypothermia occurs within domestic and non-residential settings. Most epidemiological data originate from the northern hemisphere, with little data being generally available concerning cases from New Zealand and Australia.
AIMS: The National Health Statistics Centre (New Zealand) records hospital discharges and deaths. This study isolated hypothermia cases, to quantify its incidence and identify risk groups.
METHODS: The morbidity and mortality files for the years 1979-86 (cases = 3,808,717) and 1977-86 (cases = 259,325; respectively) were searched by three investigators.
RESULTS: Hypothermia hospitalisations were identified (6.9 per 100,000 per year). There were 176 deaths from hypothermia, representing 0.07% of the 259,325 deaths from all causes for the same period (0.537 per 100,000 people per year); of these fatalities, 72.2% were classified as domestic, and 27.8% as non-residential; of the domestic fatalities, 86.6% were 65 + years and 35.5% of these were male. Within the non-residential category, 75.5% were aged 13-65, of which 94.6% were male. The hospitalisation incidence was 12.7 times the fatality incidence, with the majority of hospitalisations being of domestic origin (88.4% of total), and occurring mostly within the lower and upper age extremes. Neonatal domestic hypothermia accounted for 72.6% of all domestic hospitalisations, and the elderly constituted 72.0% of the remaining cases. The proportion of New Zealand fatalities caused by hypothermia was 0.067%; lower than reported in the United Kingdom.
CONCLUSIONS: The two main non-neonatal groups contributing to cases of hypothermia were males aged 13-65 years, and the elderly. In the aged, the proportion of hypothermia-related deaths was no different from that associated with other disorders, however, the case-fatality ratio was three times greater, highlighting the need for improving prevention and management strategies.
Vassal T, Benoit-Gonin B, Carrat F, Guidet B, Maury E, Offenstadt G.
Severe accidental hypothermia treated in an ICU: prognosis and outcome.
Chest. 2001 Dec;120(6):1998-2003. doi: 10.1378/chest.120.6.1998.
Abstract/Text
STUDY OBJECTIVES: To assess the characteristics and outcomes of patients admitted to an ICU for severe accidental hypothermia, and to identify risk factors for mortality.
METHODS: All consecutive patients admitted to an ICU between January 1, 1979, and July 31, 1998, with a temperature of < or = 32 degrees C were retrospectively analyzed. Rewarming was always conducted passively with survival blankets and conventional covers. Prognostic factors were studied by means of univariate analysis (Mann-Whitney U and chi(2) tests) and multivariate analysis (logistic regression).
RESULTS: Forty-seven patients were enrolled (mean +/- SD age, 61.7 +/- 16 years). Five patients had a cardiac arrest before ICU admission. Patient characteristics at ICU admission were as follows: temperature, 28.8 +/- 2.5 degrees C; systolic BP, 85 +/- 23 mm Hg; heart rate, 60 +/- 24 beats/min; Glasgow Coma Scale, 10.4 +/- 3.7; and simplified acute physiology score (SAPS) II, 50.9 +/- 27. Mechanical ventilation was necessary in 23 cases, and 22 patients in shock received vasoactive drugs. The mean length of stay in the ICU was 6.7 +/- 9 days. Eighteen patients (38%) died, but ventricular arrhythmia was never the cause. Univariate analysis identified several prognostic factors (p < 0.05): age (57 +/- 16 years vs 69 +/- 14 years), systolic arterial BP (93 +/- 20 mm Hg vs 71 +/- 21 mm Hg), blood bicarbonate level (23.5 +/- 5.2 mmol/L vs 16.6 +/- 6.2 mmol/L), SAPS II score (35.3 +/- 19.5 vs 72 +/- 21), mechanical ventilation (34% vs 81%), vasopressor agents (42% vs 82%), rewarming time (11.5 +/- 7.2 h vs 17.2 +/- 7 h), and discovery of the patient at home (2.3% vs 54.5%). The initial temperature did not influence vital outcome (28.9 +/- 2.6 degrees C vs 28.6 +/- 2.2 degrees C). Only the use of vasoactive drugs (odds ratio, 9; 95% confidence interval, 1.6 to 50.1) was identified as a prognostic factor in the multivariate analysis.
CONCLUSION: Severe accidental hypothermia is a rare cause of ICU admission in an urban area. Its mortality remains high, but there is no overmortality according to the SAPS II-derived prediction of death. Shock, requiring treatment with vasoactive drugs, is an independent risk factor for mortality, while initial core temperature is not. It remains to be determined whether aggressive rather than passive rewarming procedures are better.
Lankford HV, Fox LR.
The Wind-Chill Index.
Wilderness Environ Med. 2021 Sep;32(3):392-399. doi: 10.1016/j.wem.2021.04.005. Epub 2021 Jul 20.
Abstract/Text
This Lessons from History article about the wind-chill index (WCI) explores the historical polar and meteorologic literature relevant to the topic and presents unpublished work from 1939. Geographer Paul Siple (1908-1968) was a 6-time Antarctic explorer and scientist who invented and named the WCI in his doctoral dissertation at Clark University. Siple and Charles Passel (1915-2002) performed studies in Antarctica in 1940 that led to publication in 1945. This paper is often credited as the beginning of the WCI. Through years of critiques and revisions by others, these efforts evolved into the wind-chill equivalent temperatures (WCTs) used today. This essay explores the history, the science, and the overlooked originality, simplicity, and details of Siple's unpublished work. The remarkable similarity of the original chart to a current chart is shown by adapting and overlaying the 1939 WCI onto a current WCT chart with its times-to-frostbite data. The writings of Siple, Passel, and others provide an evocative supporting narrative to illustrate some of the problems of living in cold environmental conditions.
Copyright © 2021 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.
Tipton MJ, Collier N, Massey H, Corbett J, Harper M.
Cold water immersion: kill or cure?
Exp Physiol. 2017 Nov 1;102(11):1335-1355. doi: 10.1113/EP086283. Epub 2017 Sep 21.
Abstract/Text
What is the topic of this review? This is the first review to look across the broad field of 'cold water immersion' and to determine the threats and benefits associated with it as both a hazard and a treatment. What advances does it highlight? The level of evidence supporting each of the areas reviewed is assessed. Like other environmental constituents, such as pressure, heat and oxygen, cold water can be either good or bad, threat or treatment, depending on circumstance. Given the current increase in the popularly of open cold water swimming, it is timely to review the various human responses to cold water immersion (CWI) and consider the strength of the claims made for the effects of CWI. As a consequence, in this review we look at the history of CWI and examine CWI as a precursor to drowning, cardiac arrest and hypothermia. We also assess its role in prolonged survival underwater, extending exercise time in the heat and treating hyperthermic casualties. More recent uses, such as in the prevention of inflammation and treatment of inflammation-related conditions, are also considered. It is concluded that the evidence base for the different claims made for CWI are varied, and although in most instances there seems to be a credible rationale for the benefits or otherwise of CWI, in some instances the supporting data remain at the level of anecdotal speculation. Clear directions and requirements for future research are indicated by this review.
© 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.
Lott C, Truhlář A, Alfonzo A, Barelli A, González-Salvado V, Hinkelbein J, Nolan JP, Paal P, Perkins GD, Thies KC, Yeung J, Zideman DA, Soar J; ERC Special Circumstances Writing Group Collaborators.
European Resuscitation Council Guidelines 2021: Cardiac arrest in special circumstances.
Resuscitation. 2021 Apr;161:152-219. doi: 10.1016/j.resuscitation.2021.02.011. Epub 2021 Mar 24.
Abstract/Text
These European Resuscitation Council (ERC) Cardiac Arrest in Special Circumstances guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the modifications required to basic and advanced life support for the prevention and treatment of cardiac arrest in special circumstances; specifically special causes (hypoxia, trauma, anaphylaxis, sepsis, hypo/hyperkalaemia and other electrolyte disorders, hypothermia, avalanche, hyperthermia and malignant hyperthermia, pulmonary embolism, coronary thrombosis, cardiac tamponade, tension pneumothorax, toxic agents), special settings (operating room, cardiac surgery, catheter laboratory, dialysis unit, dental clinics, transportation (in-flight, cruise ships), sport, drowning, mass casualty incidents), and special patient groups (asthma and COPD, neurological disease, obesity, pregnancy).
Copyright © 2021. Published by Elsevier B.V.
Musi ME, Sheets A, Zafren K, Brugger H, Paal P, Hölzl N, Pasquier M.
Clinical staging of accidental hypothermia: The Revised Swiss System: Recommendation of the International Commission for Mountain Emergency Medicine (ICAR MedCom).
Resuscitation. 2021 May;162:182-187. doi: 10.1016/j.resuscitation.2021.02.038. Epub 2021 Mar 3.
Abstract/Text
Clinical staging of accidental hypothermia is used to guide out-of-hospital treatment and transport decisions. Most clinical systems utilize core temperature, by measurement or estimation, to stage hypothermia, despite the challenge of obtaining accurate field measurements. Recent studies have demonstrated that field estimation of core temperature is imprecise. We propose a revision of the original Swiss Staging system. The revised system uses the risk of cardiac arrest, instead of core temperature, to determine the staging level. Our revised system simplifies assessment by using the level of responsiveness, based on the AVPU scale, and by removing shivering as a stage-defining sign.
Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.
Hilmo J, Naesheim T, Gilbert M.
"Nobody is dead until warm and dead": prolonged resuscitation is warranted in arrested hypothermic victims also in remote areas--a retrospective study from northern Norway.
Resuscitation. 2014 Sep;85(9):1204-11. doi: 10.1016/j.resuscitation.2014.04.029. Epub 2014 Jun 2.
Abstract/Text
Hypothermic cardiac arrest has high mortality and few known prognostic factors. We studied retrospectively 34 victims of accidental hypothermia with cardiac arrest admitted to The University Hospital of North Norway during 1985-2013 who were resuscitated and rewarmed by extracorporeal circulation. No patient survived prior to 1999, while nine out of 24 (37.5%) survived hypothermic cardiac arrest from 1999 to 2013. The lowest measured core temperature among survivors was 13.7°C; the longest time from cardiac arrest to return of spontaneous circulation was 6 h and 52 min. The only predictor of survival identified was lower blood potassium concentration in the nine survivors compared with the non-survivors. Submersion was not associated with reduced survival. Non-survivors consumed modest hospital resources. Most survivors had a favourable neurological outcome.
Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.
Giesbrecht GG, Bristow GK.
The convective afterdrop component during hypothermic exercise decreases with delayed exercise onset.
Aviat Space Environ Med. 1998 Jan;69(1):17-22.
Abstract/Text
HYPOTHESIS: Following cold water immersion, the post-cooling decrease in esophageal temperature (Tes) (i.e., afterdrop) is 3 times greater during exercise than during shivering, presumably due to increased muscular blood flow and convective core-to-periphery heat loss with exercise (J. Appl. Physiol. 63:2375, 1987). We felt that if exercise were to commence once the afterdrop period during shivering is complete, the threat of a further decrease in Tes (i.e., a second afterdrop) during the subsequent exercise would be minimized because much of the convective capacity for core cooling would already be dissipated.
METHODS: Six subjects were each cooled three times in 8 degrees C water, until Tes decreased to 35.3 +/- 0.7 degrees C, and rewarmed by either shivering alone, exercise, or exercise commencing once a shivering afterdrop period was complete.
RESULTS: The initial afterdrop was greater during Exercise only (1.1 +/- 0.4 degrees C) than Shivering only (0.35 +/- 0.3 degrees C) and Shivering-Exercise (0.45 +/- 0.2 degrees C) (p < 0.05). In contrast, exercise caused a secondary afterdrop of only 0.38 +/- 0.3 degrees C during Shivering-Exercise (p < 0.05). The initial rewarming rate during Exercise only (3.45 degrees C.h-1) was greater than the initial (2.7 degrees C.h-1) and second (2.4 degrees C.h-1) rewarming rates during Shivering-Exercise (p < 0.05), but not significantly greater than during Shivering only (2.99 degrees C.h-1) (p < 0.1).
DISCUSSION: It is likely that during the Shivering-Exercise protocol, continued blood flow to shivering muscles: a) contributes to the initial afterdrop, and thus b) diminishes the convective capacity (or heat sink) available for further cooling during subsequent exercise.
Brown D, Ellerton J, Paal P, Boyd J.
Hypothermia Evidence, Afterdrop, and Practical Experience.
Wilderness Environ Med. 2015 Sep;26(3):437-9. doi: 10.1016/j.wem.2015.01.008. Epub 2015 Mar 29.
Abstract/Text
Durrer B, Brugger H, Syme D; International Commission for Mountain Emergency Medicine.
The medical on-site treatment of hypothermia: ICAR-MEDCOM recommendation.
High Alt Med Biol. 2003 Spring;4(1):99-103. doi: 10.1089/152702903321489031.
Abstract/Text
Strapazzon G, Procter E, Paal P, Brugger H.
Pre-hospital core temperature measurement in accidental and therapeutic hypothermia.
High Alt Med Biol. 2014 Jun;15(2):104-11. doi: 10.1089/ham.2014.1008. Epub 2014 Jun 20.
Abstract/Text
Core temperature (T core) measurement is the only diagnostic tool to accurately assess the severity of hypothermia. International recommendations for management of accidental hypothermia encourage T core measurement for triage, treatment, and transport decisions, but they also recognize that lack of equipment may be a limiting factor, particularly in the field. The aim of this nonsystematic review is to highlight the importance of field measurement of T core and to provide practical guidance for clinicians on pre-hospital temperature measurement in accidental and therapeutic hypothermia. Clinicians should recognize the difference between alternative measurement locations and available thermometers, tailoring their decision to the purpose of the measurement (i.e., intermittent vs. continual measurement), and the impact on management decisions. The importance of T core measurement in therapeutic hypothermia protocols during early cooling and monitoring of target temperature is discussed.
Pasquier M, Paal P, Kosinski S, Brown D, Podsiadlo P, Darocha T.
Esophageal Temperature Measurement.
N Engl J Med. 2020 Oct 15;383(16):e93. doi: 10.1056/NEJMvcm1900481.
Abstract/Text
Paal P, Pasquier M, Darocha T, Lechner R, Kosinski S, Wallner B, Zafren K, Brugger H.
Accidental Hypothermia: 2021 Update.
Int J Environ Res Public Health. 2022 Jan 3;19(1). doi: 10.3390/ijerph19010501. Epub 2022 Jan 3.
Abstract/Text
Accidental hypothermia is an unintentional drop of core temperature below 35 °C. Annually, thousands die of primary hypothermia and an unknown number die of secondary hypothermia worldwide. Hypothermia can be expected in emergency patients in the prehospital phase. Injured and intoxicated patients cool quickly even in subtropical regions. Preventive measures are important to avoid hypothermia or cooling in ill or injured patients. Diagnosis and assessment of the risk of cardiac arrest are based on clinical signs and core temperature measurement when available. Hypothermic patients with risk factors for imminent cardiac arrest (temperature < 30 °C in young and healthy patients and <32 °C in elderly persons, or patients with multiple comorbidities), ventricular dysrhythmias, or systolic blood pressure < 90 mmHg) and hypothermic patients who are already in cardiac arrest, should be transferred directly to an extracorporeal life support (ECLS) centre. If a hypothermic patient arrests, continuous cardiopulmonary resuscitation (CPR) should be performed. In hypothermic patients, the chances of survival and good neurological outcome are higher than for normothermic patients for witnessed, unwitnessed and asystolic cardiac arrest. Mechanical CPR devices should be used for prolonged rescue, if available. In severely hypothermic patients in cardiac arrest, if continuous or mechanical CPR is not possible, intermittent CPR should be used. Rewarming can be accomplished by passive and active techniques. Most often, passive and active external techniques are used. Only in patients with refractory hypothermia or cardiac arrest are internal rewarming techniques required. ECLS rewarming should be performed with extracorporeal membrane oxygenation (ECMO). A post-resuscitation care bundle should complement treatment.
Lim H, Kim B, Kim DC, Lee SK, Ko S.
A comparison of the temperature difference according to the placement of a nasopharyngeal temperature probe.
Korean J Anesthesiol. 2016 Aug;69(4):357-61. doi: 10.4097/kjae.2016.69.4.357. Epub 2016 Jun 22.
Abstract/Text
BACKGROUND: The purpose of this study was to compare temperatures measured at three different sites where a nasopharyngeal temperature probe is commonly placed.
METHODS: Eighty elective abdominal surgical patients were enrolled. After anesthesia induction, four temperature probes were placed at the nasal cavity, upper portion of the nasopharynx, oropharynx, and the esophagus. The placement of the nasopharyngeal temperature probes was evaluated using a flexible nasendoscope, and the depth from the nares was measured. The four temperatures were simultaneously recorded at 10-minute intervals for 60 minutes.
RESULTS: The average depths of the probes that were placed in the nasal cavity, upper nasopharynx, and the oropharynx were respectively 5.7 ± 0.9 cm, 9.9 ± 0.7 cm, and 13.6 ± 1.7 cm from the nares. In the baseline temperatures, the temperature differences were significantly greater in the nasal cavity 0.32 (95% CI; 0.27-0.37)℃ than in the nasopharynx 0.02 (0.01-0.04)℃, and oropharynx 0.02 (-0.01 to 0.05)℃ compared with the esophagus (P < 0.001). These differences were maintained for 60 minutes. Twenty patients showed a 0.5℃ or greater temperature difference between the nasal cavity and the esophagus, but no patient showed such a difference at the nasopharynx and oropharynx.
CONCLUSIONS: During general anesthesia, the temperatures measured at the upper nasopharynx and the oropharynx, but not the nasal cavity, reflected the core temperature. Therefore, the authors recommend that a probe should be placed at the nasopharynx (≈ 10 cm) or oropharynx (≈ 14 cm) with mucosal attachment for accurate core temperature measurement.
Stone JG, Young WL, Smith CR, Solomon RA, Wald A, Ostapkovich N, Shrebnick DB.
Do standard monitoring sites reflect true brain temperature when profound hypothermia is rapidly induced and reversed?
Anesthesiology. 1995 Feb;82(2):344-51. doi: 10.1097/00000542-199502000-00004.
Abstract/Text
BACKGROUND: Brain temperature is closely approximated by most body temperature measurements under normal anesthetic conditions. However, when thermal autoregulation is overridden, large temperature gradients may prevail. This study sought to determine which of the standard temperature monitoring sites best approximates brain temperature when deep hypothermia is rapidly induced and reversed during cardiopulmonary bypass.
METHODS: Twenty-seven patients underwent cardiopulmonary bypass and deep hypothermic circulatory arrest in order for each to have a giant cerebral aneurysm surgically clipped. Brain temperatures were measured directly with a thermocouple embedded in the cerebral cortex. Eight other body temperatures were monitored simultaneously with less invasive sensors at standard sites.
RESULTS: Brain temperature decreased from 32.6 +/- 1.4 degrees C (mean +/- SD) to 16.7 +/- 1.7 degrees C in 28 +/- 7 min, for an average cerebral cooling rate of 0.59 +/- 0.15 degrees C/min. Circulatory arrest lasted 24 +/- 15 min and was followed by 63 +/- 17 min of rewarming at 0.31 +/- 0.09 degrees C/min. None of the monitored sites tracked cerebral temperature well throughout the entire hypothermic period. During rapid temperature change, nasopharyngeal, esophageal, and pulmonary artery temperatures corresponded to brain temperature with smaller mean differences than did those of the tympanic membrane, bladder, rectum, axilla, and sole of the foot. At circulatory arrest, nasopharyngeal, esophageal, and pulmonary artery mean temperatures were within 1 degree C of brain temperature, even though individual patients frequently exhibited disparate values at those sites.
CONCLUSIONS: When profound hypothermia is rapidly induced and reversed, temperature measurements made at standard monitoring sites may not reflect cerebral temperature. Measurements from the nasopharynx, esophagus, and pulmonary artery tend to match brain temperature best but only with an array of data can one feel comfortable disregarding discordant readings.
Giesbrecht GG, Sessler DI, Mekjavić IB, Schroeder M, Bristow GK.
Treatment of mild immersion hypothermia by direct body-to-body contact.
J Appl Physiol (1985). 1994 Jun;76(6):2373-9. doi: 10.1152/jappl.1994.76.6.2373.
Abstract/Text
Body-to-body contact is often recommended for rewarming mildly hypothermic victims in the field. This procedure involves a euthermic individual donating heat to the recipient by direct contact in an insulated bag. However, this technique has not been critically evaluated and may not be beneficial because there is limited direct contact between recipient and donor, peripheral vasoconstriction may impair heat transfer to the core, skin warming may blunt the recipient's shivering response, and cold stress to the donor may be excessive. The present study was designed to evaluate whether donation of heat by a donor would be sufficient to enhance rewarming of a hypothermic subject (recipient). Six pairs of recipients (5 men, 1 woman) and donors (2 men, 4 women) participated in the study. Esophageal and skin temperatures, cutaneous heat flux, and oxygen consumption were measured. Recipients were immersed in 8 degrees C water until esophageal temperature decreased to a mean of 34.6 +/- 0.7 degrees C (SD). They then were rewarmed by one of three methods: rewarming by the endogenous heat generated by shivering only (SH), body-to-body rewarming (BB), or rewarming with a constant-heat source manikin (MAN). Mean afterdrop for the three conditions was 0.54 +/- 0.2, 0.54 +/- 0.2, and 0.57 +/- 0.2 degrees C for SH, BB, and MAN, respectively (NS), and the rate of rewarming was 2.40 +/- 0.8, 2.46 +/- 1.1 and 2.55 +/- 0.9 degrees C/h for SH, BB, and MAN, respectively (NS).(ABSTRACT TRUNCATED AT 250 WORDS)
大城和恵, 村上富一, 西村和隆: 道警式低体温症ラッピングによる熱喪失抑制効果と山岳救助における病院前有効事例. 登山医学 2015; vo.35: 48-54.
Hypothermia Outcome Prediction after Extracorporeal Life Support for Hypothermic Cardiac Arrest Patients. Estimation of the survival probability using HOPE [Internet]. Available from: https://hypothermiascore.org/
Pasquier M, Hugli O, Paal P, Darocha T, Blancher M, Husby P, Silfvast T, Carron PN, Rousson V.
Hypothermia outcome prediction after extracorporeal life support for hypothermic cardiac arrest patients: The HOPE score.
Resuscitation. 2018 May;126:58-64. doi: 10.1016/j.resuscitation.2018.02.026. Epub 2018 Mar 2.
Abstract/Text
AIMS: Currently, the decision to initiate extracorporeal life support for patients who suffer cardiac arrest due to accidental hypothermia is essentially based on serum potassium level. Our goal was to build a prediction score in order to determine the probability of survival following rewarming of hypothermic arrested patients based on several covariates available at admission.
METHODS: We included consecutive hypothermic arrested patients who underwent rewarming with extracorporeal life support. The sample comprised 237 patients identified through the literature from 18 studies, and 49 additional patients obtained from hospital data collection. We considered nine potential predictors of survival: age; sex; core temperature; serum potassium level; mechanism of hypothermia; cardiac rhythm at admission; witnessed cardiac arrest, rewarming method and cardiopulmonary resuscitation duration prior to the initiation of extracorporeal life support. The primary outcome parameter was survival to hospital discharge.
RESULTS: Overall, 106 of the 286 included patients survived (37%; 95% CI: 32-43%), most (84%) with a good neurological outcome. The final score included the following variables: age, sex, core temperature at admission, serum potassium level, mechanism of cooling, and cardiopulmonary resuscitation duration. The corresponding area under the receiver operating characteristic curve was 0.895 (95% CI: 0.859-0.931) compared to 0.774 (95% CI: 0.720-0.828) when based on serum potassium level alone.
CONCLUSIONS: In this large retrospective study we found that our score was superior to dichotomous triage based on serum potassium level in assessing which hypothermic patients in cardiac arrest would benefit from extracorporeal life support. External validation of our findings is required.
Copyright © 2018 Elsevier B.V. All rights reserved.
Brugger H, Bouzat P, Pasquier M, Mair P, Fieler J, Darocha T, Blancher M, de Riedmatten M, Falk M, Paal P, Strapazzon G, Zafren K, Brodmann Maeder M.
Cut-off values of serum potassium and core temperature at hospital admission for extracorporeal rewarming of avalanche victims in cardiac arrest: A retrospective multi-centre study.
Resuscitation. 2019 Jun;139:222-229. doi: 10.1016/j.resuscitation.2019.04.025. Epub 2019 Apr 22.
Abstract/Text
AIM: Evidence of existing guidelines for the on-site triage of avalanche victims is limited and adherence suboptimal. This study attempted to find reliable cut-off values for the identification of hypothermic avalanche victims with reversible out-of-hospital cardiac arrest (OHCA) at hospital admission. This may enable hospitals to allocate extracorporeal life support (ECLS) resources more appropriately while increasing the proportion of survivors among rewarmed victims.
METHODS: All avalanche victims with OHCA admitted to seven centres in Europe capable of ECLS from 1995 to 2016 were included. Optimal cut-off values, for parameters identified by logistic regression, were determined by means of bootstrapping and exact binomial distribution and served to calculate sensitivity, rate of overtriage, positive and negative predictive values, and receiver operating curves.
RESULTS: In total, 103 avalanche victims with OHCA were included. Of the 103 patients 61 (58%) were rewarmed by ECLS. Six (10%) of the rewarmed patients survived whilst 55 (90%) died. We obtained optimal cut-off values of 7 mmol/L for serum potassium and 30 °C for core temperature.
CONCLUSION: For in-hospital triage of avalanche victims admitted with OHCA, serum potassium accurately predicts survival. The combination of the cut-offs 7 mmol/L for serum potassium and 30 °C for core temperature achieved the lowest overtriage rate (47%) and the highest positive predictive value (19%), with a sensitivity of 100% for survivors. The presence of vital signs at extrication is strongly associated with survival. For further optimisation of in-hospital triage, larger datasets are needed to include additional parameters.
Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.
https://www.elso.org/ecmo-resources/glossary-of-ecmo-terms.aspx.
Swol J, Darocha T, Paal P, Brugger H, Podsiadło P, Kosiński S, Puślecki M, Ligowski M, Pasquier M.
Extracorporeal Life Support in Accidental Hypothermia with Cardiac Arrest-A Narrative Review.
ASAIO J. 2022 Feb 1;68(2):153-162. doi: 10.1097/MAT.0000000000001518.
Abstract/Text
Severely hypothermic patients, especially suffering cardiac arrest, require highly specialized treatment. The most common problems affecting the recognition and treatment seem to be awareness, logistics, and proper planning. In severe hypothermia, pathophysiologic changes occur in the cardiovascular system leading to dysrhythmias, decreased cardiac output, decreased central nervous system electrical activity, cold diuresis, and noncardiogenic pulmonary edema. Cardiac arrest, multiple organ dysfunction, and refractory vasoplegia are indicative of profound hypothermia. The aim of these narrative reviews is to describe the peculiar pathophysiology of patients suffering cardiac arrest from accidental hypothermia. We describe the good chances of neurologic recovery in certain circumstances, even in patients presenting with unwitnessed cardiac arrest, asystole, and the absence of bystander cardiopulmonary resuscitation. Guidance on patient selection, prognostication, and treatment, including extracorporeal life support, is given.
Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the ASAIO.
