The febrile parturient: choice of anesthesia

Abstract

The febrile parturient: choice of anesthesia ture and temperature control mechanisms that constantly adjust body temperature, to maintain this level. Fever is defined as an increase in core body temperature above 38 ºC, which is secondary to an increase in the hypothalamic set point. 1, 3 The human body temperature rarely exceeds 41ºC. Normal circadian fluctuation in body temperature with increase in the evening and decrease in the morning continues even in febrile patients. 4 Under normal circumstances, core body temperature is tightly regulated, with a variation of approximately 0.5ºC. While it is uncertain as to the benefits of fever, there are suggestions that the increased body temperature aids in the activation of the host immune response with augmentation of bactericidal, phagocytic and chemotactic properties of polymorphonuclear leukocytes. The negative aspects of fever include increased basal metabolic rate and increased cardiac demand. FEVER: INTERACTION WITH PREGNANCYPhysiologic changes of pregnancy include an increase in the maternal basal metabolic rate. 5 Maternal body temperature in labor is also significantly affected by the degree of physical activity and intensity of uterine contractions. Pain associ- INTRODUCTION Fever is a common clinical problem in labor and delivery suites -worldwide. The febrile parturient presents a unique diagnostic dilemma and therapeutic challenge to both an obstetrician and an anesthesiologist involved in her care. Fever can result from a variety of infectious microorganisms, tissue trauma, malignancy, drug administration, endocrine and immunological disorders. However, infection is by far the most common cause of fever in the parturient. 1, 2 The infectious etiology of fever in a parturient may be pregnancy specific, such as chorioamnionitis, or not specific to pregnancy, such as urinary tract infection. The risk to the mother and the fetus is significantly increased in pregnancy complicated by infection and fever. The diverse clinical manifestations of various infectious disorders combined with the unique anesthetic implications of pregnancy may result in life-threatening complications and significantly impact upon the practice of obstetric anesthesia.The diagnosis of infection in pregnancy often raises questions about the safety of neuraxial anesthesia in febrile patients. Despite this concern, and lack of universal guidelines, it has now been well established that the presence of infection and fever in labor does not always contraindicate the administration of regional anesthesia. 2 The decision whether to administer regional anesthesia or not in a febrile parturient should be based on an individual risk-to-benefit ratio.

Is peripartum maternal fever alone a reliable predictor of neonatal sepsis? A single‐centre, retrospective cohort study

“…The added analgesia effect reduces evaporative heat loss produced through pain‐induced hyperventilation 21,22 . This finding is consistent with higher temperatures reported in labouring women who were calm and inactive 15 . The use of variable doses of steroids has been shown to mitigate increases in maternal temperatures and Interleukin‐6 levels and therefore supports the hypothesis that drugs/catheters in the neuraxial space produce a pro‐inflammatory response 16 .…”

“…21,22 This finding is consistent with higher temperatures reported in labouring women who were calm and inactive. 15 The use of variable doses of steroids has been shown to mitigate increases in maternal temperatures and Interleukin-6 levels and therefore supports the hypothesis that drugs/catheters in the neuraxial space produce a proinflammatory response. 16 Clinicians should document the use of prolonged use of neuraxial anaesthesia and whether a rapid fall in maternal temperature occurred after it was discontinued, which may support this as the cause of fever.…”

“…Intra‐amniotic infection occurs in 0.5–0.15% of term births and accounts for 20–40% of cases of neonatal sepsis 15 . The 2010 guidelines from the CDC state that chorioamnionitis is a major risk factor for early‐onset GBS disease in women, which lead to ascending neonatal sepsis 7 .…”

“…Maternal temperature develops as the result of inflammation and may be affected by factors other than bacterial infection such as the activity and intensity of uterine contractions and the physiological changes such as an increased basal metabolic rate. 14,15 Other causes of intrapartum fever include antepartum infections such as urinary/respiratory tract infections and drugs such as prostaglandins. 16 Several investigators have reported a positive correlation between intrapartum fever and the use of epidural analgesia, a finding consistent with this study.…”

“…The main purpose of monitoring intrapartum fever is to prevent the transfer of infections to neonates with immature immune systems. Maternal temperature develops as the result of inflammation and may be affected by factors other than bacterial infection such as the activity and intensity of uterine contractions and the physiological changes such as an increased basal metabolic rate 14,15 . Other causes of intrapartum fever include antepartum infections such as urinary/respiratory tract infections and drugs such as prostaglandins 16 …”