Maternal Postop Temperature After Cesarean Delivery

Maternal Postoperative Temperature After Cesarean Delivery Under Spinal Anesthesia With Warmed Intravenous Fluids: Randomized Controlled Trial With Versus Without Lower Body Forced Air Warming

It is unclear whether routine addition of intra-operative forced-air warming in addition to warmed intravenous fluids during cesarean delivery under spinal anesthesia is beneficial. In this single-center randomized trial, we aim to test the primary null hypothesis that our current protocol of warmed intravenous fluids is similar to a combination of warmed intravenous fluids with intra-operative lower-body forced-air warming to maintain maternal temperature after cesarean delivery under spinal anesthesia. We also aim to assess the rate of maternal shivering during and after the procedure between the two groups, the maternal thermal comfort score, neonatal Apgar scores and umbilical pH levels. If we demonstrate no clinically important difference between the two interventions, clinicians will be able to continue our current protocol of warmed intravenous fluids only during cesarean delivery.

Primary aim Investigate whether a combination of intra-operative lower-body forced-air warming and warmed IV fluids is superior to our current standard of warmed IV fluids alone in influencing maternal core temperature following spinal anesthesia for cesarean delivery. Secondary aim To compare mean core temperature on arrival to post-anesthesia care unit (PACU) in women who received combination of intra-operative lower-body forced-air warming and warmed IV fluids versus IV fluids alone To compare incidence of hypothermia among women who received combination of intra-operative lower-body forced-air warming and warmed IV fluids versus IV fluids alone To compare incidence of shivering following recovery in post anesthesia care unit (PACU) in women who received combination of intra-operative lower-body forced-air warming and warmed IV fluids versus IV fluids alone To compare thermal comfort levels for women who received combination of intra-operative lower-body forced-air warming and warmed IV fluids versus IV fluids alone To compare use of meperidine in post anesthesia care unit (PACU) to treat postoperative shivering, in women who received combination of intra-operative lower-body forced-air warming and warmed IV fluids versus IV fluids alone To compare newborn outcomes (rectal temperature at birth, umbilical vein pH & Apgar scores post-delivery) in women who received combination of intra-operative lower-body forced-air warming and warmed IV fluids versus IV fluids alone

Postanesthesia care unit nurses assess primary outcome and will not know the group assignment Sample size was calculated for the primary outcome of difference between the groups in maternal temperature on arrival to the post-anesthesia care unit. We calculated the a priori sample size, WinPepi, based upon a prior publication that compared Active-Warming versus No-Warming, mean(standard deviation) 35.9(0.5)0 C versus 35.5(0.5), power 90%, 0.05 two-sided significance (Cobb et al). For clinical significance we calculated sample size with a mean difference of 0.50 C, with SD 0.5, power 90%, two sided significance with potential for 10% dropouts, total 66 women, 33 per group, and without dropouts, 22 per group total 44 women.

Intra-operative lower-body forced-air warming after spinal anesthesia and co-loading 1000 mL liters of IV warmed-fluids started prior to performing spinal anesthesia

Lower body blanket with warm air blower set at 44 deg c started after spinal anesthesia when patient placed in supine/left lat position

The primary aim is the mean core temperature on arrival to PACU. The means for the two groups will be compared.

baseline, immediately before spinal anesthesia, 60 minutes following spinal anesthesia and then every 30 minutes for 2 hours (last measurement prior to discharge)

Shivering score - 0 - no shivering - One or more of the following: piloerection, peripheral vasoconstriction, peripheral cyanosis without other cause, but without visible muscular activity - Visible muscular activity confined to one muscle group - Visible muscular activity in more than one muscle group - Gross muscular activity involving the whole body

Maternal thermal comfort scores (• Thermal comfort scale - a 0 to 10 scale will be used with the descriptors to a single question - "How warm or cold are you? o "Worst imaginable cold", " thermally neutral, " and " insufferably hot " representing the 0, 5, and 10 of the scale, respectively) will be obtained at baseline, 30 minutes during surgery, and on admission to PACU

baseline, immediately before spinal anesthesia , 60 minutes following spinal anesthesia, and then every 30 minutes for 2 hours (last measurement prior to discharge)

Inclusion Criteria: Written informed consent Age between 18-50 years old American Society of Anesthesiologists (ASA) physical status 2-3 Gestational age greater than 37 completed weeks Singleton pregnancy Elective cesarean delivery. Exclusion Criteria: Known allergy to local anesthetics Contraindication for spinal anesthesia Patient refusal Bleeding diathesis Neuropathy