Rate and Gender Dependence of the Sweating, Vasoconstriction, and Shivering Thresholds in Humans

SummaryOur aim was to compare peri-operative core temperatures and the incidence of hypothermia in obese and non-obese women with active forced-air warming. Twenty female patients scheduled for abdominal surgery were allocated to two groups according to body mass index. Ten obese (30.0-34.9 kg.m )2) and 10 non-obese (18.5-24.9 kg.m ) women received forced-air warming on their lower limbs. At the end of surgery, the mean (SD) core temperatures were 36.7 (0.5)°C in the obese group and 36.0 (0.6)°C in the non-obese group (p < 0.001). Only in the non-obese group was there a significant decrease in the intra-operative core temperature values (p < 0.001). The incidences of intra-operative hypothermia were lower in the obese group (10%) compared with non-obese group (60%; p = 0.019). In the postoperative recovery phase, the mean (SD) core temperature data were higher in the obese group than in the nonobese group (36.2 (0.4) vs 35.6 (0.5)°C, respectively (p < 0.001)). In conclusion, obese female patients have higher perioperative core temperature and a lower incidence of hypothermia compared with non-obese female patients during abdominal surgery with active forced-air warming. Accepted: 21 August 2012Unintentional peri-operative hypothermia (core temperatures between 34.5 and 35.9°C) often leads to adverse outcomes, including cardiac events secondary to sympathetic nervous system activation [1], surgicalwound infections and prolonged hospitalisation [2], coagulopathy and increased blood loss [3], impaired drug metabolism, delayed postoperative recovery period [4,5] and shivering [6]. Therefore, maintaining perioperative normothermia reduces morbidity [1][2][3] and the use of peri-operative warming devices has become routine.The prevalence of obesity has increased markedly worldwide in recent years [7]. In clinical practice, body mass index (BMI) is used to estimate the degree of obesity, which is classified in three levels: grade 1 (BMI from 30.0 to 34.9 kg.m ) [8]. The prevalence of grade-1 obesity is higher among both female and male obese populations than are the other grades [8]. Obese patients are more likely to vasoconstrict in cooler environments [9], have reduced heat redistribution from core to peripheral tissue after

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“…Female patients generally begin to respond to cold at 0.3°C higher core temperatures than male patients [30].…”

Section: Discussionmentioning

confidence: 97%

Comparison of peri‐operative core temperature in obese and non‐obese patients*

et al. 2012

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“…The thermoregulatory system is normally able to keep the core temperature constant within 0.2 ° C of a targeted value. The precision is similar in both sexes, but declines in the elderly [77] . The efferent response system has an autonomic and a behavioural part.…”

Section: Physiology Of Thermoregulationmentioning

confidence: 83%

Diagnosis, prevention and treatment of accidental and perioperative hypothermia

Brandt¹,

Mühlsteff

Imhoff³

2012

Biomedizinische Technik/Biomedical Engineering

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Accidental hypothermia and its variant, perioperative hypothermia, is a rather common clinical phenomenon in patients. This is surprising because the negative effects on clinical outcomes are well described and effective patient-warming devices are available today. The aim of this paper is to describe the physiologic background of accidental and perioperative hypothermia, the clinical relevance and existing prophylaxis and treatment options. Patient warming techniques will be discussed in detail. Remaining technical and clinical challenges and the need for further research will be addressed. We will present existing guidelines and standards and analyse the impact of accidental and perioperative hypothermia on cost effectiveness.

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“…Anticholinergic premedication increases the incidence of postanaesthetic shivering, by a peripheral mechanism that is postulated to involve alteration in skin blood flow [8]. A similar line of reasoning could lead one to suggest other possible mechanisms of action which could include serotonergic effects since ketanserin reduces postanaesthetic shivering [9] or an effect on peripheral vasodilatation.…”

Section: The Treatment Of Postoperative Shiveringmentioning

confidence: 98%

“…Temperature changes quickly induce thermoregulatory responses such as sweating, cutaneous vasoconstriction or shivering [7,8]. The Occurrence of shivering is influenced by many factors [8,9], but all these factors have not been controlled in any published clinical study and therefore a definitive conclusion may be premature.…”

Section: A Replymentioning

confidence: 99%

“…The Occurrence of shivering is influenced by many factors [8,9], but all these factors have not been controlled in any published clinical study and therefore a definitive conclusion may be premature. The aim of our study was to compare the effects of various drugs on the treatment of the postanaesthetic shivering and not to verify if its occurrence is linked to core hypothermia.…”

Section: A Replymentioning

confidence: 99%

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Alfonsi

Chauvin

1995

Anaesthesia

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[3] RICE EH, SOMBROTTO LB, MARKOWITZ JC, LEON AC. Cardiovascular morbidity in high-risk patients during ECT. American Assistance for the Anaesthetist. The treatment of postoperative shiveringThe recent study by Alfonsi and colleagues (Anaesthesia 1995; 5 0 214-7), whilst interesting, has features that make it difficult to support the conclusions offered by these authors.Alfonsi and colleagues have deliberately chosen to study hypothermic patients, thereby ignoring the 50-60% of shivering patients who, in our practice at least, are normothermic with core temperatures greater than 36°C. Indeed the lack of correlation between postoperative shivering and body temperature appears to be the norm rather than the exception [I, 23. The paper cited by Alfonsi and colleagues in support of their contention that shivering is related to core hypothermia refers to an experimental study in a small group ofvolunteers [3] and given the predominance of normothermic patients amongst those who shiver the relevance of this study to clinical anaesthesia is not clear. Alfonsi and colleagues do not comment on the number of shivering patients that they observed who were not included in the study because they were normothermic.The aetiology of postoperative shivering appears to be multifactorial. We are concerned that in Alfonsi's study the treatment groups differ markedly from each other in relation to their gender ratio, since males exhibit more postanaesthetic shivering than females, [4, 51 although we have no evidence that males and females differ in their response to treatment and so the difference may not matter in this study. Alfonsi and colleagues do not comment upon the frequency of spontaneous remission of shivering in the saline-treated group. We are aware that postoperative shivering is episodic in nature and that given the small group sizes employed in this study, it is possible that the apparent effect of fentanyl was in fact due to spontaneous remission. This would explain why the apparent rate of recurrence after fentanyl was higher than after pethidine, in that it perhaps reflects the episodic nature of postoperative shivering rather than pharmacokinetic or pharmacodynamic differences between the treatments.In our practice the treatment of choice remains low dose pethidine. We were surprised at the size of the doses of both pethidine and fentanyl employed by Alfonsi and colleagues since low doses of pethidine are well established as treatment for postoperative shivering [4,67]. Furthermore, the doses of pethidine and fentanyl employed are not equipotent with respect to analgesic activity. In a study that is attempting to investigate the mechanisms underlying the effect of pethidine this introduces a further variable which makes meaningful comparisons between treatment groups difficult.The logic that leads these authors to consider lignocaine for inclusion in the study is intriguing, but pethidine also has antimuscarinic effects in addition to its local anaesthetic effects. Anticholinergic premedication increases the incid...

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Rate and Gender Dependence of the Sweating, Vasoconstriction, and Shivering Thresholds in Humans

Cited by 251 publications

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Comparison of peri‐operative core temperature in obese and non‐obese patients*

Comparison of peri‐operative core temperature in obese and non‐obese patients*

Diagnosis, prevention and treatment of accidental and perioperative hypothermia

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