Influence of Transverse Abdominis Plane Block on Intraoperative Diaphragmatic and Respiratory Functions in Patients Receiving Laparoscopic Colorectal Surgery

Background: The positive roles of deep muscle relaxation in abdominal surgeries and transversus abdominis plane block (TAPB) in the postoperative analgesia. This study aimed to discuss the effects of TAPB on abdominal muscle relaxation, the intraoperative diaphragmatic, and the respiratory functions.
Methods: The patients were randomly divided into the TAPB group who received single-shot TAPB bilaterally (n=30), and the control group who did not receive TAPB (n=30). Both groups keep the same steps for other procedures in the surgeries and anesthesia. Four time points for monitoring were defined: The moment when pneumoperitoneum pressure stabilized following endotracheal intubation and anesthetic induction (T0), appearance of the first incisure in the pressure-volume (P-V) loop (T1), appearance of the second incisure in the P-V loop (T2), and the moment with single stimulation (SS) =20% (T3). Primary observation parameters were SS1 measured by muscle relaxation monitoring at T1, and SS2 at T2. Secondary observation parameters included surgeon’s satisfaction with surgical field and respiratory dynamics at the four time points.
Results: The two groups were comparable in age, gender, BMI, ASA grade, and operation time. The TAPB group had a dramatic reduction in the total dose of intraoperative sufentanil (0.73± 0.21 ug/kg) compared with the control group (0.87± 0.18 ug/kg) (P=0.023); Other use of drug did not differ between the two groups. The two groups did not differ significantly in SS at either T1 (SS1) or T2 (SS2). In either group, surgeon’s satisfaction with surgical field at T1 and T2 decreased dramatically compared with T0 and T3 (all P< 0.05). At each time point, the respiratory dynamics and the surgeon’s satisfaction with surgical field did not differ significantly between the two groups.
Conclusion: TAPB reduced the use of intraoperative analgesics without altering the degree of abdominal relaxation, or affecting surgeon’s satisfaction with surgical field in the patients receiving laparoscopic colorectal surgery.