Body temperature, cutaneous heat loss and skin blood flow during epidural anaesthesia for emergency caesarean section.

It is not clear how converting epidural analgesia for labour to epidural anaesthesia for emergency caesarean section affects either cutaneous vasomotor tone or mean body temperature. We hypothesised that topping up a labour epidural blocks active cutaneous vasodilation (cutaneous heat loss and skin blood flow decrease), and that as a result mean body temperature increases. Twenty women in established labour had body temperature, cutaneous heat loss and skin blood flow recorded before and after epidural top-up for emergency caesarean section. Changes over time were analysed with repeated measures ANOVA. Mean (SD) mean body temperature was 36.8 (0.5)°C at epidural top-up and 36.9 (0.6)°C at delivery. Between epidural top-up and delivery, the mean (SD) rate of increase in mean body temperature was 0.5 (0.5) °C.h-1 . Following epidural top-up, chest (p < 0.001) and forearm (p = 0.004) heat loss decreased, but head (p = 0.05), thigh (p = 0.79) and calf (p = 1.00) heat loss did not change. The mean (SD) decrease in heat loss was 15 (19) % (p < 0.001). Neither arm (p = 0.06) nor thigh (p = 0.10) skin blood flow changed following epidural top-up. Despite the lack of change in skin blood flow, the most plausible explanation for the reduction in heat loss and the increase in mean body temperature is blockade of active cutaneous vasodilation. It is possible that a similar mechanism is responsible for the hyperthermia associated with labour epidural analgesia.

The effects of a resistive warming mattress during caesarean section: a randomised, controlled trial.

BACKGROUND: The adverse effects of inadvertent perioperative hypothermia in the surgical population are well established. The aim of this study was to investigate whether a resistive warming mattress would reduce the incidence of inadvertent perioperative hypothermia in patients undergoing elective caesarean section. METHODS: A total of 116 pregnant women booked for elective caesarean section were randomised to either intraoperative warming with a mattress or control. The primary outcome was the incidence of inadvertent perioperative hypothermia, defined as a temperature <36.0 °C on admission to the recovery room. Shivering in the perioperative period, severity of shivering and the need for treatment, total blood loss, fall in haemoglobin, incidence of blood transfusion, immediate health of baby, and length of hospital stay were also recorded. RESULTS: The incidence of inadvertent perioperative hypothermia in the mattress-warmed group was significantly lower than in the control group (5.2% vs. 19.0%, P=0.043); mean temperatures differed between the two groups, 36.5 °C and 36.3 °C, respectively (P=0.046). There was also a significantly lower mean (± SD) haemoglobin change in the mattress-warmed group at -1.1±0.9 g/dL versus -1.6±0.9 g/dL in the control group (P=0.007). There was no difference in shivering (P=0.798). CONCLUSIONS: A resistive warming mattress reduced the incidence of inadvertent perioperative hypothermia and attenuated the fall in haemoglobin. The use of resistive mattress warming should be considered during caesarean section.

Controle de temperatura em intervenção cirúrgica abdominal convencional: comparação entre os métodos de aquecimento por condução e condução associada à convecção / Control de temperatura en intervención quirúrgica abdominal convencional: comparación entre los métodos de calentamiento por conducción y conducción asociada a la convección / Temperature control in conventional abdominal surgery: comparison between conductive and the association of conductive and convective warming

JUSTIFICATIVA E OBJETIVOS: Hipotermia intra-operatória é complicação frequente, favorecida por operação abdominal. A eficácia da associação dos métodos de aquecimento por condução e convecção na prevenção de hipotermia e seus efeitos no período de recuperação pós-operatória foram os objetivos deste estudo. MÉTODO: Quarenta e três pacientes de ambos os sexos de 18 a 88 anos de idade, submetidos à laparotomia xifopúbica sob anestesia geral e monitorização da temperatura esofágica, foram distribuídos de modo aleatório em dois grupos de aquecimento: COND (n = 24), com colchão de circulação de água a 37ºC no dorso e COND + CONV (n = 19), com a mesma condição associada à manta de ar aquecido a 42ºC sobre o tórax e membros superiores. Analisados peso, sexo, idade, duração da operação e anestesia, temperaturas na indução anestésica (Mi), horas consecutiva (M1, M2), final da operação (Mfo) e anestesia (Mfa), entrada (Me-REC) e saída (Ms-REC) da recuperação pós-anestésica (SRPA), além das incidências de tremores e queixas de frio no pós-operatório. RESULTADOS: Os grupos foram semelhantes em todas as variáveis analisadas, exceto nas temperaturas em M2, M3, M4, Mfo e Mfa. O grupo COND reduziu a temperatura a partir da segunda hora da indução anestésica, mas o grupo COND + CONV só na quarta hora. Em COND, observou-se hipotermia na entrada e saída da SRPA. CONCLUSÕES: Associar métodos de aquecimento retardou a instalação e diminui a intensidade da hipotermia intra-operatória, mas não reduziu a incidência das queixas de frio e tremores.

JUSTIFICATIVA Y OBJETIVOS: La Hipotermia intraoperatoria es una complicación frecuente, favorecida por la operación abdominal. La eficacia de la asociación de los métodos de calentamiento por conducción y convección en la prevención de hipotermia y sus efectos en el período de recuperación postoperatoria, fueron los objetivos de este estudio. MÉTODO: Cuarenta y tres pacientes de los dos sexos, entre 18 y 88 años de edad, sometidos a la laparotomía xifopúbica bajo anestesia general y monitorización de la temperatura esofágica, aleatoriamente distribuidos en dos grupos de calentamiento: COND (n = 24) colchón de circulación de agua a 37,0ºC en el dorso y COND + CONV (n = 19) la misma condición asociada a la manta de aire calentado a 42ºC sobre el tórax y los miembros superiores. Se analizó el peso, sexo, edad, duración de la operación y anestesia, temperaturas en la inducción anestésica (Mi), horas consecutiva (M1, M2), final de la operación (Mfo) y anestesia (Mfa), entrada (Me-REC) y salida (Ms-REC) de la recuperación postanestésica (SRPA), además de las incidencias de temblores y quejidos de frío en el postoperatorio. RESULTADOS: Los grupos fueron similares en todas las variables analizadas, excepto en las temperaturas en M2, M3, M4, Mfo y Mfa. El Grupo COND redujo la temperatura a partir de la segunda hora de la inducción anestésica, pero el grupo COND + CONV sólo en la cuarta hora. En COND se observó una hipotermia en la entrada y en la salida de la SRPA. CONCLUSIONES: El asociar métodos de calentamiento, retardó la instalación y redujo la intensidad de la hipotermia intraoperatoria, pero no redujo la incidencia de los quejidos de frío y los temblores.

BACKGROUND AND OBJECTIVES: Intraoperative hypothermia is a common complication, and its development is favored by abdominal surgeries. The efficacy of the association of conductive and convective warming methods in the prevention of hypothermia, and its effects during postoperative recovery were the objectives of this study. METHODS: Forty-three patients of both genders, ages 18 to 88 years, undergoing xyphopubic laparotomy under general anesthesia and monitoring of the esophageal temperature were randomly divided in two groups, according to the warming method: COND (n = 24), circulating-water mattress at 37º C on the back, and COND + CONV (n = 19), circulating-water mattress associated with warm air blanket at 42º C over the thorax and upper limbs. Weight, gender, age, duration of surgery and anesthesia, temperature on anesthetic induction (Mi), consecutive hours (M1, M2), end of surgery (Mes) and anesthesia (Mea), and admission (Ma-REC) and discharge (Md-REC) from the post-anesthetic recovery room (PARR), besides the postoperative incidence of tremors and complaints of cold, were analyzed. RESULTS: Both groups were similar regarding all parameters analyzed, except temperatures on M2, M3, M4, Mes, and Mea. The temperature of patients in the COND group decreased from the second hour of anesthetic induction on, but in the COND + CONV group it only happened in the fourth hour. Patients in the COND group presented hypothermia upon admission and discharge from the PARR. CONCLUSIONS: The association of different warming methods delayed the beginning and reduced the severity of intraoperative hypothermia, but it did not reduce the complaints of feeling cold and tremors.