Experimental hyperthermia in traumatic quadriplegia

Abstract

(Study Group 4) INTRODUC TION Some patients with lesions of the spinal cord may have substantial difficulty in thermoregulating under a heat s t r e s s considered mild by able-bodied persons. These patients easily develop heat exhaustion, c h a r a c t e r i z e d by cardiovascular i r r e g u l a r i t i e s , weakness and fatigue, headache, and sometimes syncope. Previous l i t e r a t u r e states that the skin of men or animals with spinal cord injury is g e n e r a lly anhidrotic in a r e a s below the level of the lesion (Leithead and Lind, 1964; Randall, W u r s t e r and Lewin, 1966;Rawson, 1963; Seckendorff and Randall, 1961). If anhidrosis is widespread, as is the case in the c e r v i c a l lesions, the patient may develop hyperthermia.Quantitative studies on spinal man r e v e a l a significant impairment of the t h e r m oregulatory sweat response over a wide area of the body. Guttmann, Silver and Wyndham (1958) observed the behavior of the c o r e t e m p e r a t u r e s of spinal man in the warm air of open wards. Patients with high c e r v i c a l lesions were largely anhidrotic over their body surface and had difficulty in maintaining normal body temperature. Nevertheless, Randall, Wurster and Lewin(1966) concluded that the isolated spinal cord is still capable of mediating a sweat reflex as did Cooper, F e r r e s and Guttmann (1951).We s u r m i s e d that quadriplegies might become hyperthermic when exposed to high ambient t e m p e r a t u r e s or to e x e r c i s e . Therefore, we studied quadriplegic subjects under a controlled heat s t r e s s and measured their thermoregulatory r esponses, thereby further c h a r a c t e r i z i n g quantitatively the quadriplegic disability. MATERIALS AND METHODS SUBJECTS:Six men, each having chronic spinal cord injury in the cervical region (CS to C3), participated in these experiments.Descriptions of their disability, age, and medications are given in Table 1. Nine control experiments were conducted on three able-bodied men under conditions identical to those in the quadriplegic experiments. Table 2 gives the characteristics of all the subjects. Each subject was tested every time at approximately the same time of the day. CONDITIONS:The subjects were submitted to total body heat exposure in an environmental chamber.Base line readings were taken at room temperature, prior to entering the hot chamber.Room conditions were T a 25°C and 50% rh, while those in the hot chamber were T a 38°C and 9% rh. Following base line readings for one hour the subjects were transferred into the environmental chamber for a maximum of 2½ hr. The subject sat inactive throughout the experimental period.

Effects of two cooling strategies on thermoregulatory responses of tetraplegic athletes during repeated intermittent exercise in the heat

“…Over the entire 80-min duration, core temperature, as measured via the telemetry pill, increased by ϳ0.5°C with a corresponding increase in mean skin temperature of 2.4°C. The increase in core temperature was less than observed by previous studies of the spinal cord injured employing oral, aural, and rectal temperature (12,29,32) and probably reflects not only the greater environmental temperature of previous exposures (35-38°C) but also the trained nature of the subject group, which may elicit improvements in heat tolerance (26). Furthermore, no change in body mass was observed during the exposure demonstrating the lack of sweating capacity within the group.…”

Extended post-exercise hyperthermia in athletes with a spinal cord injury

“…No sweating whatsoever was observed in TP athletes which is in agreement with other studies with this population under passive heat stress. 13,25 As a result, it is assumed evaporative heat loss was negligible.…”

Ventilatory changes in heat-stressed humans with spinal-cord injury

“…[9][10][11][12] Many studies that have addressed this possibility suffer methodological limitations related to controlling the thermal load, quantification of thermal strain or experimental power. Therefore, we revisited this question, but did so using a more powerful design, methods that enabled more precise control over the thermal load, a detailed quantification of thermal strain, and we minimised physiological and medical artefacts.…”