Transcutaneous carbon dioxide levels and oxygen saturation following caesarean section performed under spinal anaesthesia with intrathecal opioids.

Abstract Background Intrathecal opioids can be associated with respiratory depression which may have serious consequences. We describe the use of a non-invasive monitor (TOSCA) to measure transcutaneous carbon dioxide levels and percentage of haemoglobin oxygen saturation in post-caesarean section patients in two hospitals which used different intrathecal opioids. Methods Eighty-nine women undergoing caesarean section were monitored postoperatively until 08.00h on the first postoperative day. In addition to hyperbaric bupivacaine, patients from Hospital 1 received intrathecal diamorphine 300μg: those from Hospital 2 received intrathecal fentanyl 15μg and postoperative intramuscular morphine 10mg and were given morphine patient-controlled analgesia. Data from TOSCA were analysed the following day. Respiratory depression was defined as oxygen saturations 7kPa for >2min or the need for medical intervention for clinical respiratory depression. Results Sustained hypercapnia was recorded in 8/45 (17.8%) patients from Hospital 1 and 3/44 (6.8%) from Hospital 2. Sustained oxygen saturations Conclusions The incidence of opioid-induced respiratory depression detected by TOSCA is higher than previously reported by other monitoring methods. TOSCA may have a role in detecting subclinical respiratory depression in the obstetric population. Further studies with a control population are needed.