Malignomas after transplantation of thoracic organs]

The ultraclean air environment in a plastic isolator has been used in cerebrospinal fluid shunt interventions in an attempt to reduce the incidence of infections. The blower that maintains a continuous flow of filtered air in the operative field may create body temperature changes. In this study we assessed the temperature before, during and at the end of the operation in preterm and term infants in whom ventriculoperitoneal shunts were being placed. There were 12 preterm and 9 term infants. The duration of the operative intervention ranged from 25 to 50 min. In the preterm infants the mean initial temperature was 36.2+/-0.2 degrees C, and the final temperature was 35.7+/-0.2 degrees C. This difference was not significant. The initial temperature in the term infants was 36.26+/-0.2 degrees C, and the final temperature was 35.9+/-0.3 degrees C, also not significantly different. The surgical isolation bubble system does not alter the temperature of preterm and term infants significantly during ventriculoperitoneal shunt procedures performed within the operative times seen in this study.     

Burn wounds after resuscitation of a newborn girl

In resuscitation of an asphyctic newborn baby, a chemical hot pack was used for maintaining sufficient body temperature. The child lay for 45 min on the covered hot pack, which had a peak temperature of 54 degrees C. This led to a third degree burn (5% of BSA). The child needed split skin grafting. Control at four months of age showed a well-taken skingraft and the child was developing normally. We conclude that chemical hot packs should not be used for newborn babies unless the peak temperature in the packs is less than 44 degrees C.     

Intraperitoneal normal saline infusion for postoperative pain after laparoscopic cholecystectomy

After laparoscopic surgery carbon dioxide remains within the peritoneal cavity for a few days, commonly causing pain. This prospective randomized study was performed to determine the efficacy of intraperitoneal infusion of normal saline on postoperative pain after laparoscopic cholecystectomy. Altogether 300 patients were randomly assigned to one of five groups of 60 patients each. Group A: control group, no peritoneal infusion, no subhepatic drain. Group B: no peritoneal infusion but a subhepatic closed brain was left for 24 hours. Group C: normal saline 25 to 30 ml/kg body weight at a temperature of 37 degrees C was infused under the right hemidiaphragm and left in the peritoneal cavity. Group D: normal saline in a room temperature was infused under the right hemidiaphragm and suctioned after the pneumoperitoneum was deflated. Group E: normal saline was infused and suctioned as in group D, but a subhepatic closed drain was left for 24 hours. Postoperatively, analgesic medication usage, nausea, vomiting, and pain scores were determined at 2, 6, 12, 24, 48, and 72 hours (during hospitalization and at home). Postoperative pain was reduced significantly (p < 0.001) in the patients of groups C, D, and E versus controls, whereas no difference was observed between groups A and B. Among groups C < D and E, group E (p < 0.01) had the best results followed by group D and then group C. Intraperitoneal normal saline offered a detectable benefit to patients undergoing laparoscopic cholecystectomy. The beneficial effect was better when the fluid was suctioned after deflation of the pneumoperitoneum and even better when a subhepatic closed drain continued fluid suction during the first postoperative hours.     

The impact of hypothermia on dilutional coagulopathy

The control of hemorrhage in hypothermic patients with platelet and clotting factor depletion is often impossible. Determining the cause of coagulopathic bleeding (CB) will enable physicians to appropriately focus on rewarming, clotting factor repletion, or both. Objective: To determine the contribution of hypothermia in producing CB and ascertain if simultaneous hypothermia and dilutional coagulopathy (DC) interact synergistically. Method: Prothrombin time, partial thromboplastin time, and platelet function were determined at assay temperatures of 29 degrees to 37 degrees C on normal and critically ill, noncoagulopathic (NC) individuals. Dilutional coagulopathy was created using buffered saline and the assays repeated. Results: Hypothermic assay at < or = 35 degrees C significantly prolonged coagulation times. The effect of hypothermia on NC and DC samples was not different. Conclusion: Assays performed at 37 degrees C underestimate coagulopathy in hypothermic patients. The effect of hypothermia on NC and DC is not different, indicating the lack of a synergistic effect. Normalization of clotting requires both rewarming and clotting factor repletion.     

Cardiopulmonary bypass, rewarming, and central nervous system dysfunction

BACKGROUND: During cardiopulmonary bypass a nasopharyngeal temperature greater than 38 degrees C at the end of rewarming may indicate cerebral hyperthermia. This could exacerbate an ischemic brain injury incurred during cardiopulmonary bypass. METHODS: In a cohort of 150 aortocoronary bypass patients neuropsychologic test scores of 66 patients whose rewarming temperature exceeded 38 degrees C were compared with those who did not. There were no differences between groups with respect to demographic and intraoperative variables. RESULTS: A trend was seen for hyperthermic patients to do worse on all neuropsychologic tests in the early postoperative period but not at 3-month follow-up. By analysis of covariance hyperthermic patients did worse on the visual reproduction subtest of the Weschler memory scale at 3 months (p = 0.02), but this difference was not found by linear regression (p = 0.10). CONCLUSIONS: We were unable to demonstrate any significant deterioration in patients rewarmed to greater than 38 degrees C in the early postoperative period. The poorer performance in the visual reproduction subtest of the Wechsler memory scale at 3 months in the group rewarmed to more than 38 degrees C is interesting but far from conclusive. Caution with rewarming is still advised pending more in-depth study of this issue.     

Anesthetic management of a patient with renal cell carcinoma extending into the right atrium

A 60-year-old man with renal cell carcinoma extending through inferior vena cava into the right atrium was scheduled for the removal of the right kidney under general anesthesia and the cardiopulmonary bypass technique. In order to obtain a clear operative field and to minimize the risk for pulmonary embolism of necrotizing tumor, total circulatory arrest under profound hypothermia (20 degrees C) was performed. Anesthesia was maintained with high doses of fentanyl (62 micrograms.kg-1), midazolam and supplemented with enflurane. We attempted to prevent circulatory collapse due to acute pulmonary embolism by tumor fragments during operation. The body temperature of the patient was decreased down to 20 degrees C for protecting central nervous system with the minimal damage. No complications occurred during anesthesia and the post-operative period. For the safe anesthetic management of the patient such as our case, adequate monitoring of circulation and protection of central nervous system are essential.     

Malnutrition in geriatric patients: a neglected problem?

PURPOSE: The authors report their experience with the translumbar inferior vena cava (IVC) approach for central venous access during a 6-year period at three teaching hospital sites. PATIENTS AND METHODS: Twenty-nine percutaneous IVC central venous access catheters were inserted in 22 patients during a 6-year period in the radiology departments of three teaching hospital sites. All patients had undergone unsuccessful attempts at conventional central venous access. Information was gathered by retrospective radiologic and hospital chart review. RESULTS: All attempted placements were successful. Catheters were in place for a total of 3,510 catheter days. The average length of catheter placement was 121 days (range, 14-536 days). Life-table analysis predicted catheter function rates of 55% and 29% at 6 and 12 months, respectively. Three procedure-related complications occurred. A lower pole branch of the right renal artery was inadvertently entered with a 22-gauge needle during attempted IVC puncture in one patient without clinical sequelae. A second patient developed a small groin hematoma at the femoral venous puncture site, which resolved spontaneously. A third patient developed a moderate retroperitoneal hematoma, which resolved without specific intervention. The sepsis rate was 2.8 infections per 1,000 catheter days with an average time to infection of 127 days (range, 10-536 days). CONCLUSION: In the authors' experience of 29 translumbar central venous catheter insertions, all attempts were successful. Percutaneous central venous access via the IVC is a safe and effective option for patients in whom more conventional access is not possible.     

Distribution of adriamycin in mice under conditions of local hyperthermia which improve systemic drug therapy

Local tumor hyperthermia (LTH) (43 degrees C for 60 minutes) enhanced the effectiveness of Adriamycin (ADR) (10 mg/kg iv) administered systemically against the 16C mouse mammary adenocarcinoma. LTH was produced by the local application of 2450 MHz microwaves to sc implanted tumors. During LTH the intratumor temperature uniformity was +/- 0.5 degrees C and the rectal temperatures were 36 degrees C--38 degrees C. The simultaneous application of LTH and ADR resulted in tumor growth delays which were greater than those expected from the addition of individual treatments. Enhanced effectiveness of these treatments did not occur if the two treatments were separated by 4 hours. Cures were observed only in the treatment groups that received drug and heat simultaneously. Measurements of the tissue distribution of ADR and its metabolites using 14C-ADR indicated that the uptake of radioactivity in the heated tumors was not increased by LTH. A greater percentage of the radioactivity in heated tumors was recovered as ADR metabolites and correspondingly less radioactivity was recovered as unchanged ADR.     

Outcome and cost analysis for outpatient skin grafting

BACKGROUND: To reduce cost, outpatient surgery is advocated when feasible; however, the potential of compromising outcome is a concern. The purpose of this review is to assess patient outcome and cost for managing operative burn injuries without hospitalization. METHODS: During the past 18 months, 54 patients were identified with burns amenable to operative debridement and skin grafting without hospitalization. Twenty patients chose to be hospitalized and underwent prompt skin grafting. Operative skin grafting as an outpatient was chosen by the remaining 34 patients. Of these, four patients were subsequently hospitalized postoperatively (two for pain, one for cellulitis, and one for vomiting). RESULTS: Hospitalized patients and outpatients were similar in age and extent of burn; however, those hospitalized underwent skin grafting sooner after injury (2.1 +/- 0.4 days for inpatients vs. 11.5 +/- 0.8 days for outpatients; mean +/- SEM). Inpatients also had a significantly larger area skin-grafted (286 +/- 24 cm2 for inpatients vs. 178 +/- 14 cm2 for outpatients). Graft take was very good in each group. Cost, as indexed by patient charge, was substantially less for outpatients ($2,397 +/- $222) than for inpatients ($17,220 +/- $410). CONCLUSION: These results demonstrate a significant cost reduction with nonhospitalized operative care of burn injuries without any overt detriment in outcome, thus endorsing outpatient skin grafting when amenable. This review also illustrates that delaying operative intervention reduces the burn area required for grafting.     

Local hypothermia protects the retina from ischaemic injury in vitrectomy

AIMS: Hypothermic irrigating solutions were used during vitrectomy in pressure induced ischaemic eyes so that their effects on retinal function and histological changes could be investigated. METHODS: After anaesthetised albino rabbits underwent closed vitrectomy, their vitreous cavities were continuously irrigated for 30 minutes at a perfusion pressure of 140 mm Hg. The rabbits were divided into three groups according to their intraocular perfusion temperatures--8 degrees C, 22 degrees C, and 38 degrees C. Electroretinograms were taken before and after irrigation. Glutamate levels in the vitreous were examined after irrigation. Eyes were enucleated on the seventh postoperative day and examined histologically. RESULTS: On the seventh postoperative day, the recovery rate of a-wave amplitudes was significantly lower in the 38 degrees C group than in the 8 degrees C group, and that of b-wave amplitudes was significantly lower in the 38 degrees C group than in either the 8 degrees C or 22 degrees C group. Retinal damage in the 38 degrees C group revealed more severe histological impairment than in either the 8 degrees C or 22 degrees C group. Oedema of the inner retinal layer was significant in both the 22 degrees C and 38 degrees C groups. Glutamates reached peak values 30 minutes after the end of ischaemia in the 38 degrees C group. However, no significant glutamate increases were detected 15 to 60 minutes after ischaemia in either the 8 degrees C or 22 degrees C group. CONCLUSION: Local hypothermia during vitrectomy in acute ischaemic eyes appears to decrease retinal damage.     

Determination of optimum retrograde cerebral perfusion conditions

Retrograde cerebral perfusion through a superior vena caval cannula is a new technique used to protect the brain during operations on the aortic arch. We measured cerebral tissue blood flow, oxygen consumption, and cerebrospinal fluid pressure under various perfusion conditions in hypothermic (20 degrees C) mongrel dogs (n = 18, 12.8 +/- 0.6 kg) to determine the optimum conditions for retrograde cerebral perfusion. Retrograde cerebral perfusion was performed by infusion via the superior vena caval cannula and drainage via the ascending aortic cannula while the inferior vena cava and azygos vein were clamped. Retrograde cerebral perfusion was performed as the external jugular venous pressure was changed from 15 to 35 mm Hg in increments of 5 mm Hg. Cerebral tissue blood flow was measured by the hydrogen clearance method. Hypothermic retrograde cerebral perfusion with an external jugular venous pressure of 25 mm Hg provided about half the cerebral tissue blood flow of hypothermic (20 degrees C) cardiopulmonary bypass with a flow rate of 1000 ml/min (13.7 +/- 7.9 versus 32.7 +/- 8.5 ml/min per 100 gm). It decreased significantly as the external jugular venous pressure was decreased from 25 to 15 mm Hg but did not increase significantly as the external jugular venous pressure was increased from 25 to 35 mm Hg. Whole-body oxygen consumption during hypothermic retrograde cerebral perfusion with an external jugular venous pressure of 25 mm Hg was one quarter of that during hypothermic cardiopulmonary bypass (3.4 +/- 0.7 versus 12.7 +/- 5.6 ml/min) and varied in proportion to external jugular venous pressure. The cerebrospinal fluid pressure was a little lower than the external jugular venous pressure (19.2 +/- 4.5 mm Hg versus 24.8 +/- 2.4 mm Hg) but also varied with the external jugular venous pressure. The cerebrospinal fluid pressure remained lower than 25 mm Hg so long as the external jugular venous pressure remained lower than 25 mm Hg. High external jugular venous pressure was associated with high intracranial pressure, which restricts cerebral tissue blood flow and may cause brain edema. We believe that a venous pressure of 25 mm Hg is the optimum condition for retrograde cerebral perfusion.     

The effect of dry heat on mite, cat, and dog allergens

BACKGROUND: Various techniques have been tried in an attempt to reduce allergen levels in homes. This study investigated the effect of dry heat on mite, cat, and dog allergens. METHODS: Samples (50 mg) of Dermatophagoides pteronyssinus and D. farinae cultures, and of house dust rich in the major cat and dog allergens Fel d 1 and Can f 1 were heated for 5, 10, 15, 30, and 60 min at 60 degrees, 80 degrees, 100 degrees, 120 degrees, and 140 degrees C. Control samples remained at room temperature. Extracts were assayed with the appropriate two-site mono- or mono/polyclonal sandwich ELISA. RESULTS: For Der p 1, the breakdown was proportional to temperature and heating time; after 30 min at 120 degrees C, allergen levels were reduced to < 1% of control. Der p 2 was more heat stable, requiring 140 degrees C for 30-60 min to achieve > 99% reduction. D. farinae groups 1 and 2 allergens showed results similar to those obtained with D. pteronyssinus. In contrast, Can f 1 and Fel d 1 were considerably more thermostable, with 50% and 70%, respectively, of allergen remaining after 60 min at 140 degrees C. CONCLUSIONS: The effect of dry heat on allergens increased with increasing time and temperature, cat and dog allergens demonstrating greater heat resistance than mite allergens. Dry heating methods may represent an alternative technique for removal of mite allergens; however, the greater stability of Fel d 1 and Can f 1 suggests that this procedure may not be appropriate for pet allergens.     

Amnioinfusion with Hartmann's solution: a safe distention medium for endoscopic fetal surgery in the ovine model

In this study, we have investigated the maternal effects of distending the uterine cavity with Hartmann's solution in 2nd trimester equivalent pregnant sheep. In 7 pregnant ewes, double endoscopic cannulation of the amniotic cavity was performed under general anesthesia, and 1 liter of Hartmann's solution at 38 degrees C, radiolabeled with 99mTc-red blood cells, was infused. Maternal central venous pressure, hematocrit, serum and amniotic fluid osmolarity, and amniotic fluid volume were measured at nine time points within a 2-hour period. Over this time interval, no significant fluid shift to the maternal compartment was observed. We detected no adsorption of radioactivity to the fetus or membranes, and no diffusion of radioactivity to maternal or fetal tissues was noticed. We conclude from these experiments that following double cannulation and intra-amniotic infusion of Hartmann's solution into the 2nd-trimester pregnant ovine uterus, no significant shift of fluid to the maternal compartment was observed over a 2-hour time period.     

The effects of inadequate humidity

The use of heated humidification in adults does not appear to be an important factor in maintaining body temperature in adults. Heat and moisture losses certainly can be reduced with heated humidification, but the contribution to temperature regulation appears small. The use of an HME reduces heat loss form the respiratory tract, but this loss is minute compared with losses from the skin, fluid administration, and the operative site. In neonates, the use of heated humidification during surgery may help contribute to thermal balance owing to the unique issues of temperature regulation and control in these patients.     

Ethanol anapyrexia in rats

In the present series of experiments we tested whether ethanol decreases body temperature by impairing thermal regulation (poikilothermia) or by shifting the set point downwards. The central temperature of rats kept in a thermocline and the selected ambient temperature were recorded by telemetry. After an IP injection of 2 g/kg of ethanol the rats selected an ambient temperature 7 degrees C lower than the one they selected before the ethanol injection and 8 degrees C lower than the one selected by the same rats after saline injection. At the same time the central temperature decreased by 2.5 degrees C. After about 40 min the rats preferred warmer ambient temperatures and 10 min later the central temperature began to rise. When, after ethanol, the rats were kept at 30 degrees C the central temperature remained at the normal level. At 35-36 degrees C the central temperature of normal rats without ethanol rose, in 1 h, from 37 degrees C to 39.75 degrees C. The results suggest that ethanol hypothermia is due to a downward shift of the set point and, in fact, is an anapyrexia, a condition inverse to fever.     

Comparison of responses of men to immersion in circulating water at 40.0 and 41.5 degrees C

BACKGROUND: The recommended maximum water temperature for public hot tubs has been set at 40.0 degrees C, but no research has been published on human immersion in hot water at higher temperatures. HYPOTHESIS: We hypothesized that thermoregulatory and cardiovascular responses at two water temperatures would be proportional to the water:blood temperature gradients. METHODS: Six healthy men were immersed for 21 min in circulating hot water at 40.0 and 41.5 degrees C in separate trials in random order 1-3 wk apart. Measurements included heart rate, systolic BP, esophageal, rectal, and non-immersed skin temperatures, sweat rate, and perceived comfort. RESULTS: The rise in all body temperatures, sweat rate, and heart rate were significantly greater in the 41.5 vs. 40.0 degrees C water. Peak esophageal temperatures were 38.3 +/- 0.2 degrees C vs. 37.8 +/- 0.03 degrees C, peak sweat rates were 0.48 +/- 0.05 vs. 0.32 +/- 0.03 kg x m(-2) x h(-1), and peak heart rates were 123 +/- 7 vs. 108 +/- 5 bpm, respectively. Systolic BPs followed different patterns of response in each trial, whereas diastolic pressures were not different between trials. Comfort at each level of immersion was reduced during the 41.5 degrees C trial compared with the 40.0 degrees C in excess of that predicted by difference in esophageal temperature between the trials. CONCLUSIONS: These results suggest that risks of hyperthermia or adverse cardiovascular effects in hot tubs may not be greater in water above 40.0 degrees C unless perceptual judgment is impaired. Hypotension when standing to exit the tub occurred in both trials and may represent a potential hazard to hot tub use.     

Effect of resistance exercise training on cortical and cancellous bone in mature male rats

The thermal inactivation kinetics of Salmonella enteritidis PT4 between 49 and 60 degrees C were investigated. Using procedures designed to eliminate methodological artifacts, we found that the death kinetics deviated from the accepted model of first-order inactivation. When we used high-density stationary-phase populations and sensitive enumeration, the survivor curves at 60 degrees C were reproducibly biphasic. The decimal reduction time at 60 degrees C (D60 degrees C) of the tail subpopulation was more than four times that of the majority population. This difference decreased with decreasing temperature; i.e., the survivor curves became more linear, but the proportion of tail cells remained a constant proportion of the initial population, about 1 in 10(4) to 10(5). Z plots (log D versus temperature) for the two populations showed that the D values coincided at 51 degrees C, indicating that the survivor curves should be linear at this temperature, and this was confirmed experimentally. Investigations into the nature of the tails ruled out genotypic differences between the populations and protection due to leakage from early heat casualties. Heating of cells at 59 degrees C in the presence of 5 or 100 micrograms of chloramphenicol per ml resulted in reductions in the levels of tailing. These reductions were greatest at the higher chloramphenicol concentration. Our results indicate that de novo protein synthesis of heat shock proteins is responsible for the observed tailing. Chemostat-cultured cells heated at 60 degrees C also produced biphasic survivor curves in all but one instance. Cells with higher growth rates were more heat sensitive, but tailing was comparable with batch cultures. Starved cells (no dilution input) displayed linear inactivation kinetics, suggesting that during starvation a rapid heat shock response cannot be initiated.     

Hypothermia eliminates isoflurane requirements at 20 degrees C

BACKGROUND: Hypothermia decreases anesthetic requirements, but the temperature that completely eliminates anesthetic needs has not been previously determined. METHODS: Eight female goats were anesthetized with isoflurane and catheters were placed in the femoral artery and cranial vena cava, after which the right carotid artery and external jugular vein were dissected free. Peripheral temperature was monitored in the rectum and core temperature in the vena cava. A thermistor was placed in the epidural space via a small burr hole to monitor brain temperature. Minimum alveolar concentration (MAC) for isoflurane was determined by eliciting gross, purposeful movement with a tail clamp. Cardiopulmonary bypass (CPB) was established using bubble oxygenators with venous blood drained from a jugular vein and arterial blood infused with a roller pump into the carotid artery. The animals were cooled to approximately 29 degrees C, and MAC redetermined, after which further cooling to 20 degrees C was accomplished. Isoflurane was eliminated, core and brain temperature adjusted in 2-3 degrees C increments, and the tail clamp applied until two temperatures were found that just permitted and just prevented movement. The animals were rewarmed, isoflurane added, and post-CPB MAC determined. RESULTS: At 38.5 degrees C, pre-CPB MAC was 1.3 +/- 0.1% (mean +/- SEM). At 29.0 degrees C, MAC was 0.7 +/- 0.1%, and the anesthetizing temperature was 20.1 +/- 0.6 degrees C. At 37.3 degrees C, post-CPB MAC was 1.0 +/- 0.1% (P < 0.05 vs. pre-CPB). CONCLUSIONS: These results confirm the rectilinear decrease in MAC seen in previous studies and establishes the anesthetizing temperature at 20 degrees C.     

Responses to temperate, cold, and hot environments and the effect of physical training

Ten young men underwent several tests before and after a training program: a bicycle ergometer test and 60 min of moderate exercise performed at a temperate 24 degrees C; the same work load performed in heat (40.0 degrees C DB, 30.4 degrees C WB) for 3 h; and cold (10 degrees C) exposure for 60 min. Training consisted of 13 1-h sessions of hard, strenuous, and exhaustive work performed in temperate conditions four times a week. Training resulted in substantial decreases in heart rate and rectal temperature responses to exercise in temperate, minor increases in hot, and no significant changes in cold conditions. Subjects who showed good responses to heat, also showed good responses at 24 degrees C, and poor compensatory responses to cold, which were indicated by relatively low heat production and rectal temperature values, and relatively high body heat loss and extremities temperature values. Subjects who showed poor heat tolerance also showed poor responses in temperate and good compensatory responses in cold conditions. Positive correlation coefficients were found between rectal temperatures in the three environments, and between heart rate and sweat rate responses in temperate and hot conditions. The results indicated that moderately severe training causes minor tolerance improvements in heat and no changes in cold, and that responses in temperate, cold, and hot environments are interdependent.     

Systemic hypothermia after spinal cord compression injury in the rat: does recorded temperature in accessible organs reflect the intramedullary temperature in the spinal cord?

This article addresses one basic issue regarding the use of systemic hypothermia in the acute management of spinal cord injury, namely, how to interpret temperature recordings in accessible organs such as the rectum or esophagus with reference to the spinal cord temperature. Thirty-six rats, divided into six groups, were randomized to laminectomy or to severe spinal cord compression trauma, and were further randomized to either a cooling/rewarming procedure or continuous normothermia (esophageal temperature 38 degrees C) for 90 min. The first procedure comprised normothermia during the surgical procedure, followed by lowering of the esophageal temperature from 38 degrees C to 30 degrees C (the hypothermic level), a 20-min steady-state period at 30 degrees C, rewarming to 38 degrees C, and finally a 20-min steady-state period at 38 degrees C. The esophageal, rectal, and epidural temperatures were recorded in all animals. The intramedullary temperature was also recorded invasively in four of the six groups. We conclude that the esophageal temperature is safe and easy to record and, in our setting, reflects the epidural temperature. The differences registrated may reflect a true deviation of the intramedullary temperature due to initial environmental exposure and secondary injury processes. Our results indicate that the esophageal temperature exceeds the intramedullary temperature during the initial recording and final steady state following rewarming, but not during the most crucial part of the experiment, the hypothermic period. The core temperature measured in the esophagus can therefore be used to evaluate the intramedullary temperature during alterations of the systemic temperature and during hypothermic periods.