A Comparative Study of Intrathecal Fentanyl as Adjuvant to Hyperbaric Bupivacaine for Post Cesarean Section Analgesia at Muhimbili National Hospital

Abstract

Spinal anaesthesia sometimes referred as subarachnoid block (SAB) is the preferred technique for cesarean section for most women, it is simpler to perform and presence of cerebral spinal fluid gives a more certain end point and hence higher degree of success, It has advantage of rapid onset, less drug use with minimum neonatal depression as well as less incidence of aspiration pneumonitis. It produces fixed duration of anaesthesia and also intraoperative hypotension. Due to fixed duration of anaesthesia after cesarean section there comes the need of addition post-operative analgesics. Supplementation of analgesics after cesarean using spinal anaesthesia has been a challenge and this has been attributed by the fact that individuals have different threshold for pain onset since pain is unpleasant sensation may result in devastating effects to individuals. Addition of intrathecal opioids to local anaesthetic agents have shown to be beneficial due to the reason that it leads to reduction of the dose of local anesthetic agent to be used resulting to less side effects such as intraoperative hypotension, hemodynamic instability but also provide prolonged early postoperative analgesia with good neonatal outcome. Side effects associated with the use of bupivacaine are dose dependent hence this can be overcome by lowering the dose of local anaesthetic agent and mixing it with additive such as fentanyl. BROAD OBJECTIVE: To determine the duration of post cesarean section analgesia of intrathecal fentanyl as an adjuvant to hyperbaric bupivacaine in post cesarean section patients at Muhimbili National Hospital. METHODOLOGY: This study was a single blinded controlled Study which was conducted at Muhimbili National Hospital, Dar-es-Salaam, Tanzania. The study duration was about six months beginning from July 2016.Study population included patients who underwent cesarean section under spinal anaesthesia using hyperbaric bupivacaine coadministered with or without fentanyl. Preoperatively a thorough history, physical examination and airway assessment was done using a special designed form. Patients were divided into two groups by simple random selection one group was given Intrathecal heavy bupivacaine while the other group was given intrathecal heavy bupivacaine combined with fentanyl. Intraoperatively data recording was done using a special designed form and all intraoperative vitals were monitored and recorded throught the procedure as well as fetal outcome. Patients were followed up to 24 hours post operative with special designed questionnaire to record duration of post operative analgesia, additional post operative analgesics including their doses and frequency, type and occurrence of associated side effects. Data was analyzed using SPSS version 11.0 software. Categorical variables were presented as frequency while continuous variables were presented as mean. Chi-square analysis and student ttest was utilized in analysis of categorical and continuous variables respectively. All analysis was two-sided and the level of significance was set at value of P< 0.05.A sum total of one million and five hundread thousands, Tanzanian shillings (1,500,000/=Tshs) was used to conduct the study.