Observational Study of Peripheral Skin Temperature Changes Following Spinal Anaesthesia for Category 4 Lower Segment Caesarean Section (LSCS)

The hypothesis is that peripheral skin temperature will rise following spinal anaesthesia and that this temperature change could be used as an indicator of potential success of spinal anaesthesia.

This is an observational study. The investigators will obtain ethics committee approval for conducting the study. ASA 1 and 2 full term (37-42 weeks), parturients with singleton pregnancy, normal placental position, scheduled for category 4 LSCS under 'single-shot' spinal anaesthesia will be recruited. The investigators intend to recruit 60 parturients. The parturients will undergo an informed consent process including an explanation of the methods and risks of the study. A patient information leaflet will be provided for the parturients.

The data will be collected on a password protected spread-sheet with no patient identifiable information. A grant for funding has been granted from the Obstetric Anaesthetists' Association.

Prior to establishment of spinal anaesthesia, the skin temperature of the parturient's feet will be measured on the dorsum of the right and left feet above space between the 2nd and 3rd metatarsal bones while the parturient is lying supine with left lateral tilt. The temperature will be measured by Covidien Mon-a-Therm skin temperature probes and a Braun Welch Allyn tympanic membrane thermometer device. Following spinal injection when the parturient is lying supine with lateral tilt, the temperature will be re-measured by Covidien Mon-a-Therm skin temperature probes and a Braun Welch Allyn tympanic membrane thermometer device. The skin temperature of the parturient's feet will be monitored continuously by the Covidien Mon-a-Therm skin temperature probes using the GE Healthcare monitor with readings transcribed every 1 minute by the research investigator until transfer onto the bed at the end of surgery. The skin temperature of the parturient's feet will be measured and recorded every 1 minute using a Braun Welch Allyn tympanic membrane thermometer device until the sterile drapes are applied prior to commencing the operation and then again after removal of the drapes prior to transfer onto the bed. Following transfer to the post-operative recovery area, the skin temperature of the parturient's feet will be measured and recorded every 10 minutes using a Braun Welch Allyn tympanic membrane thermometer device until discharged to the ward from the recovery area (usually 2 hours from departmental guidelines).

Theatre room temperature will be measured and recorded at the start of anaesthesia and at the end of surgery using a room thermometer. Surgical drapes will be applied over the parturient's lower limbs during the caesarean section procedure as per the investigators routine practice. The ambient temperature under the surgical drapes will be measured and recorded at the start of anaesthesia and at the end of surgery using a room thermometer.