Hypothermia: a cold influence on trauma

Preventative measures taken against hypothermia in selected Durban hospitals' emergency centres and operating theatres

Introduction

Hypothermia is common in emergency general surgical patients. It is known to be associated with major complications in multiple organ systems. It is also easily preventable with the use of safe and cost-effective equipment. However, by observation, it appears that this equipment is used too infrequently thus resulting in unnecessary harm to patients.

Methods

This descriptive, observational, cross-sectional study was conducted in two arms to evaluate both emergency centres and operating theatres in the major state hospitals in Durban. It was conducted as an audit as well as a questionnaire-based study, to ascertain the availability of equipment used to prevent hypothermia and also how appropriately the equipment was being used.

Results

There was good availability of equipment in both the operating theatres and the emergency centres. However it was being used very poorly, particularly in emergency centres (41% of responses deemed not beneficial to patients versus 29% from operating theatres; 39% of answers beneficial versus 54% from operating theatres). Institutions with hypothermia-prevention protocols scored significantly better than those without a protocol (59% versus 25% beneficial; p = 0.01).

Conclusion

In the field of hypothermia prevention, there was sufficient equipment to result in optimal patient care. However there appears to be a lack of knowledge amongst health care providers, resulting in suboptimal use of this equipment. Protocolised management may provide a solution to this problem and improve patient outcomes.

The pathophysiological mechanisms of the onset of death through accidental hypothermia and the presentation of "The little match girl" case

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.

Sustained hypothermia accelerates microvascular thrombus formation in mice

Cold is supposed to be associated with alterations in blood coagulation and a pronounced risk for thrombosis. We studied the effect of clinically encountered systemic hypothermia on microvascular thrombosis in vivo and in vitro. Ferric chloride-induced microvascular thrombus formation was analyzed in cremaster muscle preparations from hypothermic mice. Additionally, flow cytometry and Western blot analysis was used to evaluate the effect of hypothermia on platelet activation. To test whether preceding hypothermia predisposes for enhanced thrombosis, experiments were repeated after hypothermia and rewarming to 37°C. Control animals revealed complete occlusion of arterioles and venules after 742 ± 150 and 824 ± 172 s, respectively. Systemic hypothermia of 34°C accelerated thrombus formation in arterioles and venules (279 ± 120 and 376 ± 121 s; P < 0.05 vs. 37°C). This was further pronounced after cooling to 31°C (163 ± 57 and 281 ± 71 s; P < 0.05 vs. 37°C). Magnitude of thrombin receptor activating peptide (TRAP)-induced platelet activation increased with decreasing temperatures, as shown by 1.8- and 3.0-fold increases in mean fluorescence after PAC-1 binding to glycoprotein (GP)IIb-IIIa and 1.6- and 2.9-fold increases of fibrinogen binding on incubation at 34°C and 31°C. Additionally, tyrosine-specific protein phosphorylation in platelets was increased at hypothermic temperatures. In rewarmed animals, kinetics of thrombus formation were comparable to those in normothermic controls. Concomitantly, spontaneous and TRAP-enhanced GPIIb-IIIa activation did not differ between rewarmed platelets and those maintained continuously at 37°C. Moderate systemic hypothermia accelerates microvascular thrombosis, which might be mediated by increased GPIIb-IIIa activation on platelets but does not cause predisposition with increased risk for microvascular thrombus formation after rewarming.