Effects of Body Temperature Changes on Hypoxic Pulmonary Vasoconstriction in Isolated Lungs of Rabbits / 대한마취과학회지

BACKGROUND: We studied the effects of body temperature changes and repeated hypoxic stimulation on hypoxic pulmonary vasoconstriction (HPV). METHODS: We isolated lungs from 15 rabbits and perfused them at a constant flow of 30 ml/kg/min with a 3% albumin-physiologic salt solution containing autologous blood. After a 30-minute stabilization, the temperature of the perfusate was changed from 38oC to 32oC gradually. The lungs were ventilated for 15 minutes with a hyperoxic gas mixture consisting of 95% oxygen and 5% carbon dioxide and then for 5 minutes with a hypoxic gas mixture consisting of 3% oxygen and 5% carbon dioxide with the balance being nitrogen. We repeated the hypoxic stimulation 3 times at the same temperature. The mean pulmonary artery pressure changes and ventilation-related parameters were measured at each hypoxic stimulation. RESULTS: With the first hypoxic stimulation, the hypoxic pressure response at the end of the 5-minute hypoxic period decreased significantly at 32oC. With the second and the third hypoxic stimulations, the hypoxic pressure responses at the end of the 5-minute hypoxic period decreased significantly at both 34oC and 36oC. With repeated hypoxic stimulations, the hypoxic pressure responses potentiated significantly at all temperatures. The baseline mean pulmonary artery pressure increased significantly below 34oC. CONCLUSION: The HPV decreased with the reduction in body temperature and was potentiated by repeated intermittent hypoxia; also, the pulmonary vascular resistance increased with the reduction in the body temperature.

The Effect of Warm Irrigation Fluid on Body Temperature during Laparoscopic Surgery in Gynecologic Patients / 대한마취과학회지

BACKGROUND: Perioperative hypothermia is a common problem during both laparotomy and laparoscopic surgery. Hypothermia during laparoscopic surgery is related to the use of irrigation fluid and the large volume of CO2 for maintaining pneumoperitoneum. The aim of this study is to estimate whether the use of warm irrigation fluid can reduce the incidence of hypothermia and the decrease of body temperature. METHODS: Forty-two female patients undergoing elective laparoscopic surgery were randomly divided into 2 groups. Group 1 (n = 20) was given an ambient temperature irrigation fluid and group 2 (n = 22) a warm irrigation fluid. The core esophageal body temperatures of all the patients were measured every 10 minutes for 70 minutes. Body temperature 10 minutes after induction was a control value. The degree of body temperature decrease was measured, and the incidence of hypothermia was recorded. RESULTS: The incidences of hypothermia in group 2 were decreased significantly 60 and 70 minutes after induction, compared with those of group 1. The degree of body temperature decrease was revealed to be significantly different between the two groups starting 50 minutes after induction. CONCLUSIONS: The use of warm irrigation fluid during laparoscopic surgery can reduce the incidence of hypothermia and degree of body temperature decrease.

The Effect of Warm Irrigation Fluid on Body Temperature during Laparoscopic Surgery in Gynecologic Patients / 대한마취과학회지

BACKGROUND: Perioperative hypothermia is a common problem during both laparotomy and laparoscopic surgery. Hypothermia during laparoscopic surgery is related to the use of irrigation fluid and the large volume of CO2 for maintaining pneumoperitoneum. The aim of this study is to estimate whether the use of warm irrigation fluid can reduce the incidence of hypothermia and the decrease of body temperature. METHODS: Forty-two female patients undergoing elective laparoscopic surgery were randomly divided into 2 groups. Group 1 (n = 20) was given an ambient temperature irrigation fluid and group 2 (n = 22) a warm irrigation fluid. The core esophageal body temperatures of all the patients were measured every 10 minutes for 70 minutes. Body temperature 10 minutes after induction was a control value. The degree of body temperature decrease was measured, and the incidence of hypothermia was recorded. RESULTS: The incidences of hypothermia in group 2 were decreased significantly 60 and 70 minutes after induction, compared with those of group 1. The degree of body temperature decrease was revealed to be significantly different between the two groups starting 50 minutes after induction. CONCLUSIONS: The use of warm irrigation fluid during laparoscopic surgery can reduce the incidence of hypothermia and degree of body temperature decrease.

Interactions between size and temperature influence fecundity and longevity of a tortricid moth, Zeiraphera canadensis.

Females of Zeiraphera canadensis Mut. & Free., the spruce bud moth, were reared in the laboratory at constant and alternating temperatures, and in an outdoor insectary, to (1) determine the effects of temperature, age and size on several reproductive parameters and, (2) to test the hypothesis that body size-temperature interactions influence longevity and realized fecundity. Egg maturation was linearly related to age and large moths developed eggs at a higher rate than small ones. Mcan lifetime oviposition rate reached a maximum and remained stable at temperatures ≥20° C while the mean lifetime rate of egg maturation increased linearly with temperature, indicating that higher temperatures adversely affect oviposition. The production of nonviable eggs increased with age but also with temperature, suggesting high temperature (≥25° C) reduces egg quality and/or hinders fertilization. The realized fecundity and longevity of females reared under an alternating temperature regime (mean 20° C) was significantly less than that of females reared at constant 20° C. Similar realized fecundity, longevity and mean lifetime oviposition rates for females reared at temperatures alternating between 10 and 25° C (mean 20° C) and those at constant 25° C reflected the inability of females to recover from elevated diurnal temperatures. Longevity was positively related to female body size at constant 15 and 20° C but the relationships were negative for moths exposed to diurnal temperatures equal to or exceeding 25° C. Due to the reduced longevity of large moths at high temperatures, linear regressions between size and realized fecundity were only significant at constant temperatures ≤20° C. At higher temperatures, the size-fecundity relationship became curvilinear as a result of the diminished reproductive output of large individuals. Reduced fecundity and longevity of large females at high temperatures may have been due to elevated internal temperatures of large-bodied moths. Large females in a controlled-environment chamber maintained at 25° C developed an internal temperature excess (i.e. temperature above ambient) of nearly 2° C while small-bodied females exceeded ambient by only 0.3° C. However, when held at 20° C, the temperature excess of large-bodied moths was much less than 1° C and small-bodied females did not differ from ambient. Such interactions between temperature and body size suggest that there should be stabilizing selection toward moderate-sized individuals and may explain the absence of size-related effects on fecundity and longevity previously reported for several other lepidopterans.