Effect of ropivacaine administered intrathecally on pulmonary function after caesarean section

Objective To investigate the effect of ropivacaine administered intrathecally on the pulmonary function after caesarean section.Methods Thirty-six ASA Ⅰ or Ⅱ parturients,aged 22-34 yr,with body mass index ≤35 kg/m2,undergoing elective cesarean section,were randomly divided into 2 groups (n=18 each):bupivacaine group (group B) and ropivacaine group (group R).Spinal anesthesia was performed at L3,4 interspace and 0.5％ bupivacaine 1.8 ml (in cerebrospinal fluid 3 ml) and 1.0％ ropivacaine 1.4 ml (in cerebrospinal fluid 3 ml) were injected into the subarachnoid space over 10 s in groups B and R respectively.Forced vital capacity (FVC),forced expiratory volume first second (FEV1) and peak expiratory flow (PEF) were measured by spirometry before surgery (T0),and at 1,1.5 and 2 h after intrathecal injection (T1-3).The motor block score was recorded at T1-3.It is regarded as the criteria for respiratory dysfunction that the measured values of FVC and FEV1 are lower than their 80 ％ and 70 ％ predicted levels respectively.Results FVC and FEV1 were significantly decreased at T1 compared with the baseline value at T0 in both groups (P＜0.05).Compared with that at T1,PEF was significantly increased at T2,3 in group R (P ＜0.05).Compared with group B,PEF at T1 and motor block score atT3 were significantly decreased in group R (P＜0.05).The respiratory dysfunction was not found in both groups.Conclusion Spinal anesthesia with ropivacaine and bupivacaine can inhibit the parameter level of carly pulmonary function afrer caesarean section in parturient without respiratory complications,but the pulmonary function still remains normal. Key words: Amides; Bupivacaine; Subarachnoid space; Cesarean section; Respiratory function tests