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Savioli G, Ceresa IF, Bavestrello Piccini G, Gri N, Nardone A, La Russa R, Saviano A, Piccioni A, Ricevuti G, Esposito C. Hypothermia: Beyond the Narrative Review-The Point of View of Emergency Physicians and Medico-Legal Considerations. J Pers Med 2023; 13:1690. [PMID: 38138917 PMCID: PMC10745126 DOI: 10.3390/jpm13121690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/14/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023] Open
Abstract
Hypothermia is a widespread condition all over the world, with a high risk of mortality in pre-hospital and in-hospital settings when it is not promptly and adequately treated. In this review, we aim to describe the main specificities of the diagnosis and treatment of hypothermia through consideration of the physiological changes that occur in hypothermic patients. Hypothermia can occur due to unfavorable environmental conditions as well as internal causes, such as pathological states that result in reduced heat production, increased heat loss or ineffectiveness of the thermal regulation system. The consequences of hypothermia affect several systems in the body-the cardiovascular system, the central and peripheral nervous systems, the respiratory system, the endocrine system and the gastrointestinal system-but also kidney function, electrolyte balance and coagulation. Once hypothermia is recognized, prompt treatment, focused on restoring body temperature and supporting vital functions, is fundamental in order to avert preventable death. It is important to also denote the fact that CPR has specificities related to the unique profile of hypothermic patients.
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Affiliation(s)
- Gabriele Savioli
- Emergency Department, IRCCS Policlinico San Matteo, 27100 Pavia, Italy
| | - Iride Francesca Ceresa
- Emergency Department and Internal Medicine, Istituti Clinici di Pavia e Vigevano, Gruppo San Donato, 27029 Vigevano, Italy;
| | | | - Nicole Gri
- Niguarda Cancer Center, ASST Grande Ospedale Metropolitano Niguarda, Piazza dell’Ospedale Maggiore, 3, 20162 Milano, Italy
| | - Alba Nardone
- Emergency Department, Ospedale Civile, 27058 Voghera, Italy
| | - Raffaele La Russa
- Department of Clinical and Experimental Medicine, Section of Forensic Pathology, University of Foggia, 71122 Foggia, Italy
| | - Angela Saviano
- Emergency Department, Fondazione Policlinico Universitario A. Gemelli, IRCCS, 00168 Roma, Italy; (A.S.); (A.P.)
| | - Andrea Piccioni
- Emergency Department, Fondazione Policlinico Universitario A. Gemelli, IRCCS, 00168 Roma, Italy; (A.S.); (A.P.)
| | - Giovanni Ricevuti
- Department of Drug Science, University of Pavia, 27100 Pavia, Italy;
| | - Ciro Esposito
- Nephrology and Dialysis Unit, ICS Maugeri, University of Pavia, 27100 Pavia, Italy;
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Haouzi P, McCann M, Tubbs N. Respiratory effects of low and high doses of fentanyl in control and β-arrestin 2-deficient mice. J Neurophysiol 2021; 125:1396-1407. [PMID: 33656934 DOI: 10.1152/jn.00711.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We have investigated the potential acute desensitizing role of the β arrestin 2 (β-arr2) pathway on the ventilatory depression produced by levels of fentanyl ranging from analgesic to life-threatening (0.1 to 60 mg/kg ip) in control and β-arr2-deficient nonsedated mice. Fentanyl at doses of 0.1, 0.5, and 1 mg/kg ip-corresponding to the doses previously used to study the role of β-arr2 pathway-decreased ventilation, but along the V̇e/V̇co2 relationship established in baseline conditions. This reduction in ventilation was therefore indistinguishable from the decrease in breathing during the periods of spontaneous immobility. Above 1.5 mg/kg, however, ventilation was depressed out of proportion of the changes in metabolic rate, suggesting a specific depression of the drive to breathe. The ventilatory responses were similar between the two groups. At high doses of fentanyl (60 mg/kg ip) 1 out of 20 control mice died by apnea versus 8 out of 20 β-arr2-deficient mice (P = 0.008). In the surviving mice, ventilation was however identical in both groups. The ventilatory effects of fentanyl in β-arr2-deficient mice, reported in the literature, are primarily mediated by the "indirect" effects of sedation/hypometabolism on breathing control. There was an excess mortality at very high doses of fentanyl in the β-arr2-deficient mice, mechanisms of which are still open to question, as the capacity of maintaining a rhythmic, although profoundly depressed, breathing activity remains similar in all of the surviving control and β-arr2-deficient mice.NEW & NOTEWORTHY When life-threatening doses of fentanyl are used in mice, the β-arrestin 2 pathway appears to play a critical role in the recovery from opioid overdose. This observation calls into question the use of G protein-biased μ-opioid receptor agonists, as a strategy for safer opioid analgesic drugs.
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Affiliation(s)
- Philippe Haouzi
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania
| | - Marissa McCann
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania
| | - Nicole Tubbs
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania
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Postnatal changes in O2 and CO2 sensitivity in rodents. Respir Physiol Neurobiol 2020; 272:103313. [DOI: 10.1016/j.resp.2019.103313] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 08/31/2019] [Accepted: 10/02/2019] [Indexed: 02/06/2023]
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Dzal YA, Milsom WK. Hypoxia alters the thermogenic response to cold in adult homeothermic and heterothermic rodents. J Physiol 2019; 597:4809-4829. [PMID: 31365126 DOI: 10.1113/jp277183] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 07/26/2019] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS For small mammals living in a cold, hypoxic environment, supplying enough O2 to sustain thermogenesis can be challenging. While heterothermic mammals are generally more tolerant of cold and hypoxia than homeothermic mammals, how they regulate O2 supply and demand during progressive cooling in hypoxia is largely unknown. We show that as ambient temperature is reduced in hypoxia, body temperature falls in both homeotherms and heterotherms. In the homeothermic rat, a decrease in O2 consumption rate and lung O2 extraction accompany this fall in body temperature, despite a relative hyperventilation. Paradoxically, in heterothermic mice, hamsters and ground squirrels, body temperature decreases more than in the homeothermic rat, even though they maintain ventilation, increase lung O2 extraction and maintain or elevate their O2 consumption rates. Variation in cold and hypoxia tolerance among homeotherms and heterotherms reflects divergent strategies in how O2 supply and demand are regulated under thermal and hypoxic challenges. ABSTRACT Compared to homeothermic mammals, heterothermic mammals are reported to be exceptionally tolerant of cold and hypoxia. We hypothesised that this variation in tolerance stems from divergent strategies in how homeotherms and heterotherms regulate O2 supply versus O2 demand when exposed to hypoxia during progressive cooling. To test this hypothesis, we exposed adult rodents ranging in their degree of heterothermic expression (homeotherm: rats, facultative heterotherms: mice and hamsters, and obligate heterotherm: ground squirrels) to either normoxia (21% O2 ) or environmental hypoxia (7% O2 ), while reducing ambient temperature from 38 to 5°C. We found that when ambient temperature was reduced in normoxia, all species increased their O2 consumption rate and ventilation in parallel, maintaining a constant ventilatory equivalent and level of lung O2 extraction. Surprisingly, body temperature fell in all species, significantly so in the heterotherms. When ambient temperature was reduced in hypoxia, however, the homeothermic rat decreased their O2 consumption rate and lung O2 extraction despite an increase in their ventilatory equivalent, indicative of a relative hyperventilation. Heterotherms (mice, hamsters and ground squirrels), on the other hand, decreased their ventilatory equivalent, but increased lung O2 extraction and maintained or elevated their O2 consumption rates, yet their body temperature fell even more than in the rat. These results are consistent with the idea that homeotherms and heterotherms diverge in the strategies they use to match O2 supply and O2 demand, and that enhanced cold and hypoxia tolerance in heterotherms may stem from an improved ability to extract O2 from the inspired air.
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Affiliation(s)
- Yvonne A Dzal
- Department of Biology and Centre for Forest Interdisciplinary Research, University of Winnipeg, Winnipeg, Manitoba, Canada
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
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Avraam J, Cohen G, Drago J, Frappell PB. Prenatal nicotine exposure increases hyperventilation in α4-knock-out mice during mild asphyxia. Respir Physiol Neurobiol 2015; 208:29-36. [PMID: 25596543 DOI: 10.1016/j.resp.2015.01.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 01/07/2015] [Accepted: 01/08/2015] [Indexed: 10/24/2022]
Abstract
Prenatal nicotine exposure alters breathing and ventilatory responses to stress through stimulation of nicotine acetylcholine receptors (nAChRs). We tested the hypothesis that α4-containing nAChRs are involved in mediating the effects of prenatal nicotine exposure on ventilatory and metabolic responses to intermittent mild asphyxia (MA). Using open-flow plethysmography, we measured ventilation (V̇(E)) and rate of O2 consumption ( V̇(O2)) of wild-type (WT) and α4-knock-out (KO) mice, at postnatal (P) days 1-2 and 7-8, with and without prenatal nicotine exposure (6 mg kg(-1) day(-1) beginning on embryonic day 14). Mice were exposed to seven 2 min cycles of mild asphyxia (10% O2 and 5% CO2), each interspersed with 2 min of air. Compared to WT, α4 KO mice had increased air V̇(E) and V̇(O2) at P7-8, but not P1-2. Irrespective of age, genotype had no effect on the hyperventilatory response (increase in V̇(E)/V̇(O2)) to MA. At P1-2, nicotine suppressed air V̇(E) and V̇(O2) in both genotypes but did not affect the hyperventilatory response to MA. At P7-8 nicotine suppressed air V̇(E) and V̇(O2) of only α4 KO's but also significantly enhanced V̇(E) during MA (nearly double that of WT; p<0.001). This study has revealed complex effects of α4 nAChR deficiency and prenatal nicotine exposure on ventilatory and metabolic interactions and responses to stress.
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Affiliation(s)
- Joanne Avraam
- Department of Zoology, Latrobe University, Melbourne, VIC 3086, Australia.
| | - Gary Cohen
- Department of Women & Child Health, Neonatal Unit, Karolinska Institute, Elevhemmet H1:02 S171-76, Stockholm, Sweden
| | - John Drago
- Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville, VIC 3052, Australia
| | - Peter B Frappell
- Department of Zoology, Latrobe University, Melbourne, VIC 3086, Australia; Adaptational and Evolutionary Respiratory Physiology Laboratory, School of Zoology, Hobart, TAS, Australia
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Jeican II. The pathophysiological mechanisms of the onset of death through accidental hypothermia and the presentation of "The little match girl" case. CLUJUL MEDICAL 2014; 87:54-60. [PMID: 26527999 PMCID: PMC4462406 DOI: 10.15386/cjm.2014.8872.871.iij1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 01/13/2014] [Indexed: 12/02/2022]
Abstract
Hypothermia and death caused by hypothermia may be found in a number of fiction works, mainly in novels. In the well-known story “The Little Match Girl” by Hans Christian Andersen, one can notice that the descriptions of the phenomena occurring before the girl’s death are in fact a literary presentation of the pathophysiological mechanisms of the onset of death through accidental hypothermia. This essay presents the medical aspects of the story written by Andersen.
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Affiliation(s)
- Ionuţ Isaia Jeican
- Medical student, Faculty of General Medicine, Iuliu Haţieganu University of Medicine and Pharmacy, Cluj-Napoca
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Carregaro AB, Cruz ML, Cherubini AL, Luna SP. Influência da temperatura corporal de cascavéis (Crotalus durissus) submetidas à anestesia com cetamina. PESQUISA VETERINARIA BRASILEIRA 2009. [DOI: 10.1590/s0100-736x2009001200003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
O estudo objetivou verificar a influência da temperatura corporal nos parâmetros fisiológicos e nos períodos de indução e recuperação anestésicos de cascavéis (Crotalus durissus) anestesiadas com cetamina. Os animais foram previamente submetidos à hipotermia (HIPO) (<22°C) e normotermia (30°C) (NORMO) e anestesiados com 80mg/kg IM de cetamina. Foram avaliados os períodos de latência e recuperação da anestesia por meio do tônus de cabeça, tônus muscular e reflexo de endireitamento. Mensurou-se a frequência cardíaca (FC), tempo de apnéia e temperatura corporal em 0 min e 5, 10, 15, 30, 60, 90, 120 min e análise dos gases sanguíneos em 0 min, 30 e 60 min. Não houve diferença em relação ao período de latência entre os grupos. A recuperação dos animais em HIPO foi mais prolongada (5,5 horas) que em NORMO (3,5 horas). Obteve-se FC no grupo NORMO superior que no grupo HIPO. O tempo de apnéia manteve o mesmo padrão em ambos os grupos. Em relação ao basal, tanto em HIPO quanto em NORMO o tempo de apnéia diminuiu acentuadamente entre 5 e 30 min. Observou-se acidose respiratória no grupo NORMO apenas em 0 min. O SvO2 elevou-se significativamente após 30 min, o mesmo ocorrendo com a PvO2. A PvCO2 diminuiu em ambos os grupos após 30 min. Evidenciou-se que a temperatura corporal influencia intrinsecamente o período de recuperação de cascavéis anestesiadas com cetamina.
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Tourneux P, Libert JP, Ghyselen L, Léké A, Delanaud S, Dégrugilliers L, Bach V. [Heat exchanges and thermoregulation in the neonate]. Arch Pediatr 2009; 16:1057-62. [PMID: 19410440 DOI: 10.1016/j.arcped.2009.03.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2008] [Revised: 09/22/2008] [Accepted: 03/25/2009] [Indexed: 11/16/2022]
Abstract
The newborn's energy expenditure is used in order of priority for: (i) basic metabolism; (ii) body temperature regulation and (iii) body growth. Thermal regulation is an important part of energy expenditure, especially for low birth-weight infants or preterm newborns. The heat exchanges with the environment are greater in the infant than in the adult, explaining the increased risk of body hypo- or hyperthermia. The newborn infant is a homeotherm, but over a long period of time, he cannot maintain the thermal processes. Further developments are expected to improve the infant's thermal environment, with assessment of the various heat exchange mechanisms by conduction, convection, radiation and evaporation. The quantification of the respective parts of these exchanges would improve nursing care through clinical procedures or equipment used to ensure the control of the optimal thermohygrometric conditions in incubators, especially when the likelihood of excessive body cooling is high. The present review focuses on the various body heat exchange mechanisms, the thermoregulation processes of the newborn, and their implications in clinical usage and limitations in the neonatal intensive care unit.
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Affiliation(s)
- P Tourneux
- PériTox (EA4285-unité mixte Ineris), faculté de médecine, UPJV, 3, rue des Louvels, 80036 Amiens cedex, France.
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Frappell PB. Ventilation and metabolic rate in the platypus: insights into the evolution of the mammalian breathing pattern. Comp Biochem Physiol A Mol Integr Physiol 2003; 136:943-55. [PMID: 14667857 DOI: 10.1016/s1095-6433(03)00273-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The platypus (Ornithorhyncus anatinus) is characterized by a rate of oxygen consumption (V(O2))that is higher than that reported for other similar sized monotremes, similar to marsupials and somewhat lower than eutherians. The platypus is also characterized by a breathing pattern, more typical of a diving mammal, with a high 'inspiratory drive' and a post-inspiratory pause. Further, the platypus reveals an attenuated hyperventilatory response to hypoxia and a reduced hyperpnoea to hypercapnia; such a response to these chemical stimuli is commonly observed in semi-fossorial and diving mammals. Nevertheless, under conditions of normoxia, ventilation (V(E))is matched to (V(O(2)) such that the convection requirement (V(E)/V(O2)) is similar to that reported for other mammals (approx. 37). The apparent consistency of the convection requirement in mammals suggests the blueprint for the design of the mammalian respiratory system has remained an interspecies constant in the three divergent extant sub-classes of mammals.
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Affiliation(s)
- Peter B Frappell
- Adaptational and Evolutionary Respiratory Physiology Laboratory, Department of Zoology, La Trobe University, Melbourne, VIC 3086, Australia.
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Zinchuk V, Dorokhina L, Maltsev A. Prooxidant–antioxidant balance in rats under hypothermia combined with modified hemoglobin–oxygen affinity. J Therm Biol 2002. [DOI: 10.1016/s0306-4565(01)00099-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Mortola JP, Frappell PB. Ventilatory responses to changes in temperature in mammals and other vertebrates. Annu Rev Physiol 2000; 62:847-74. [PMID: 10845114 DOI: 10.1146/annurev.physiol.62.1.847] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This article reviews the relationship between pulmonary ventilation (VE) and metabolic rate (oxygen consumption) during changes in ambient temperature. The main focus is on mammals, although for comparative purposes the VE responses of ectothermic vertebrates are also discussed. First, the effects of temperature on pulmonary mechanics, chemoreceptors, and airway receptors are summarized. Then we review the main VE responses to cold and warm stimuli and their interaction with exercise, hypoxia, or hypercapnia. In these cases, mammals attempt to maintain both oxygenation and body temperature, although conflicts can arise because of the respiratory heat loss associated with the increase in ventilation. Finally, we consider the VE responses of mammals when body temperature changes, as during torpor, fever, sleep, and hypothermia. In ectotherms, during changes in temperature, VE control becomes part of a general strategy to maintain constant relative alkalinity and ensure a constancy of pH-dependent protein functions (alphastat regulation). In mammals on the other hand, VE control is aimed to balance metabolic needs with homeothermy. Therefore, alphastat regulation in mammals seems to have a low priority, and it may be adopted only in exceptional cases.
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Affiliation(s)
- J P Mortola
- Department of Physiology, McGill University, Montreal, Quebec, Canada
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