The Effect of Combined General/Epidural Anesthesia Versus General Anesthesia on Diaphragmatic Function

The aim of this study was to investigate whether robot assisted laparoscopic radical prostatectomy give rise to the impairment of diaphragmatic function postoperatively, and whether combined general/epidural anesthesia could provide better postoperative diaphragmatic function.

Diaphragmatic dysfunction after abdominal surgery can result in extended hospital stay and increased medical costs, because it is related with atelectasis, lung collapse or pneumonia. The mechanism of diaphragm dysfunction is thought to be from not only direct injury to abdominal wall and viscera but inhibitory reflexes of phrenic activity. Thoracic or upper abdominal surgery is suggested as a risk factor of postoperative diaphragm dysfunction, and perioperative analgesic modality is also known to affect diaphragm movements. But there has been no trial to investigate the effect of laparoscopic pelvic surgery such as prostatectomy on diaphragm movement. Moreover, it is not clear if minimally invasive Robot-assisted laparoscopic radical prostatectomy (RALRP) has any influence on respiratory and diaphragm functions.

• Drug: epidural 250mL of 0.2% ropivacaine and 2 μg/mL of fentanyl, 5 mL/hr continuous infusion and 0.5 mL bolus dose

  Before the induction of anesthesia, epidural catheter was inserted in group GE at T8/9, T9/10, or T10/11 interspinous space with a 17-gauge Tuohy needle in lateral decubitus position and advanced 5 cm cephalad. .

  Epidural analgesia was maintained using the patient-controlled analgesia technique containing 250 mL of 0.2% ropivacaine and 2 μg/mL fentanyl with setting of 5 mL/hr for continuous infusion and 0.5 mL of bolus dose. Lockout time was set to 15 min.

  General anesthesia was induced with 2 mg/kg of propofol and 50 mg of rocuronium. After tracheal intubation, anesthesia was maintained with sevoflurane. All the patients were ventilated with controlled mode of 8 mL/kg of ideal body weight and respiratory rate was adjusted to maintain end-tidal carbon dioxide between 35-40 mmHg.

• Drug: no epidural drug administered

  Patients allocated to general anesthesia group and DID NOT receive epidural anesthesia.

  General anesthesia was induced with 2 mg/kg of propofol and 50 mg of rocuronium. After tracheal intubation, anesthesia was maintained with sevoflurane. All the patients were ventilated with controlled mode of 8 mL/kg of ideal body weight and respiratory rate was adjusted to maintain end-tidal carbon dioxide between 35-40 mmHg.

• Experimental: combined general/epidural anesthesia
  epidural catheter was inserted in group GE at T8/9, T9/10, or T10/11 interspinous space with a 17-gauge Tuohy needle in lateral decubitus position and advanced 5 cm cephalad. Epidural analgesia was maintained using the patient-controlled analgesia technique.
  Intervention: Drug: epidural 250mL of 0.2% ropivacaine and 2 μg/mL of fentanyl, 5 mL/hr continuous infusion and 0.5 mL bolus dose
• Active Comparator: General anesthesia
  Patients allocated to general anesthesia group did not receive epidural anesthesia.
  Intervention: Drug: no epidural drug administered

Inclusion Criteria:

• Patients of over 18 years of age undergoing elective Robot-assisted laparoscopic radical prostatectomy

Exclusion Criteria:

• Patients with previous history of smoking, cardiopulmonary or neuromuscular disease or obesity (body mass index > 30 kg.m-2)