Original Contribution
Hypothermia in a desert climate: severity score and mortality prediction

https://doi.org/10.1016/j.ajem.2007.10.016Get rights and content

Abstract

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°C in the severe hypothermia (9 cases, 5.3%), 21.4°C in the moderate (40 cases, 23.7%), and 29.3°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 ≥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.

Section snippets

Background

Hypothermia, defined as a reduction in the body's core temperature to less than 35°C [1], is a well-known thermoregulatory disorder since ancient times. One of the first documented references of hypothermia in Israel appears in the Bible: “King David was now old, advanced in years; and though they covered him with bedclothes, he never felt warm” [2].

In recent years, hypothermia has been increasingly recognized as a significant problem in clinical practice [3], [4]. Between 1979 and 2002, a

Methods and definitions

We conducted a retrospective study at Soroka University Medical Center, a 1200-bed tertiary care teaching medical center located in Beer Sheva, which serves as the only regional hospital for Southern Israel (estimated population of 700 000). The city of Beer Sheva is situated at 275 m above sea level. The climate in the area is of semiarid type [9]. January is the coldest month, with temperatures from 5°C to 10°C, and August is the hottest month at 18°C to 38°C. The average rain fall is 260 mm a

Results

During 6 years of the study 169 patients with hypothermia were admitted to the hospital. Thus, the annual rate of hypothermia identified at the hospital admission was 7.8 per 100 000 adult population. This rate varied between different age groups with the lowest being between 18 and 24 years (2.5 per 100 000), and the highest, in the group older than 75 years (65.9 per 100 000). Hypothermia was defined as mild in 120 (71.0%), moderate in 40 (23.7%) and severe in 9 (5.3%) of the cases. The major

Discussion

Hypothermia is a condition encountered not infrequently in the ED [12]. Traditionally, hypothermia has been related to a breakdown of the normal mechanisms of thermoregulation as a consequence of exposure to overwhelming cold [4], [8], [12], [13]. The actual worldwide number of “outdoor” patients presenting with hypothermia is unclear. Poverty, homelessness, and alcoholism are frequently associated conditions [3], [4], [12]. The mortality of these patients with moderate or severe accidental

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First and second authors equally contributed to the article.

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