The Effect Of Muscle Relaxants On Cardiorespiratory Factors Which Is Influenced By Pneumoperitoneum

ObjectiveThe creation of the pneumoperitoneum reduces respiratory-system compliance increases peak inspiratory and mean airway pressures and induces hemodynamic changes. Administration of muscle relaxants is considered as necessary to prevent high intraabdominal and peak inspiratory pressures and improve hemodynamic function induced by pneumoperitoneum during laparoscopy. In the present study,we compared the cardiorespiratory factors during total intravenous anesthesia for laparoscopic pelvic surgery with or without supplemental muscle relaxants to determine if cardiorespiratory factors changes during laparoscopy are affected by neuromuscular block.Methods40 female ASA I or II patients undergoing laparoscopic pelvic surgeries were recruited into the study. Patients were randomized to two groups (A and B) and received total intravenous anesthesia. Anesthesia was induced with propofol target effect-site concentration 4.0 ug/mL, remifentanil 3.5 ng/mL, A base line record of the neuromuscular monitoring was made after the loss of consciousness and it was stabilized for 2 min,then a bolus dose of rocuronium 0.6mg/kg was administered to the patients. Endotracheal intubation was performed when the twitch response was completely abolished. Maintenance of anesthesia was established with 2.0-4.0ug/mL of propofol and 2-5 ng/mL of remifentanil.The intensity of neuromuscular blockade assessed by acceleromyograph (Organon TOF watch SX). Patients in Group B received rocuronium as continuous infusion when one TOF twitch response was observed and adjusted the rate of rocuronium infusion for maintain Tlvalue to 0-10%. Rocuronium administration was stopped at the time 20 to 30 min before the surgery procedure completed. Patients in Group A,however, no supplemental muscle relaxants were administered. Heart rate (HR) and systolic arterial pressure (SAP), mean arterial pressure (MAP),diastolic arterial pressure (DAP), peak inspiratory pressure (PIP), mean airway pressure (mPaw), expired minute ventilation (MV), end-tidal carbon-dioxide concentration (EtCO2), were measured during the pneumoperitoneum. Respiratory system compliance (Ceff rs) was calculated as quotient of tidal volume (VT) and PIP. Duration of end of dressing application to trachea was extubated and time to recovery room were recorded.ResultsAfter creation of pneumoperitoneum (IAP 12 mmHg), there was a significant increase of HR,SBP, MBP,DBP, PIP, mPaw and, EtCO2, Ceff rs decreased by 6 mL. cmH2O-1.But there were no group differences in HR, SAP, DAP, EtCO2, PIP, Ceff rs between groups A and B. Duration of end of dressing application to trachea was extubated and time to recovery room were significantly shorter in the group A than in the group B.ConclusionsPneumoperitoneum result in more significant effects in respiratory and cirulation system.However,the cardiorespiratory factors during laparoscopy are not affected by neuromuscular block agents. Laparoscopic surgery can be performed with only a single dose of neuromuscular block.