Experimental hyperthermia in traumatic quadriplegia.

Abstract

Some patients with lesions of the spinal cord may have substantial difficulty in thermoregulating under a heat stress considered mild by able-bodied persons. These patients easily develop heat exhaustion, characterized by cardiovascular irregularities, weakness and fatigue, headache, and sometimes syncope. Previous literature states that the skin of men or animals with spinal cord injury is generally anhidrotic in areas below the level of the lesion (Leithead and Lind, 1964; Randall, Wurster and Lewin, 1966; Rawson, 1963; Seckendorff and Randall, 1961). If anhidrosis is widespread, as is the case in the cervical lesions, the patient may develop hyperthermia. Quantitative studies on spinal man reveal a significant impairment of the thermoregulatory sweat response over a wide area of the body. Guttmann, Silver and Wyndham (1958) observed the behavior of the core temperatures of spinal man in the warm air of open wards. Patients with high cervical 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, Ferres and Guttmann (1951). We surmised that quadriplegies might become hyperthermic when exposed to high ambient temperatures or to exercise. Therefore, we studied quadriplegic subjects under a controlled heat stress and measured their thermoregulatory responses, thereby further characterizing 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.