Sevoflurane requirements during coloproctologic surgery: difference between two different epidural regimens

Comparison of continuous thoracic epidural with paravertebral block on perioperative analgesia and hemodynamic stability in patients having open lung surgery

BACKGROUND

Epidural analgesia can result in perioperative hypotension in patients having thoracotomy. This randomized prospective study assessed the effects of epidural and paravertebral analgesia on hemodynamics during thoracotomy.

METHODS

Thirty-two patients were randomized to receive either epidural analgesia (n = 16, 0.25% levobupivacaine and 30 μg/kg morphine) or paravertebral block (n = 16; 0.5% levobupivacaine and 30 μg/kg morphine). Oxygen delivery, stroke volume and systemic vascular resistance indices, heart rate, and mean arterial pressure measurements were performed before administration of local anesthetic, after induction of general anesthesia, institution of 1-lung ventilation, first skin incision, retractor placement, lung-inflation maneuver, and at last skin suture. The primary end point was the volume of the colloid infusion necessary to maintain oxygen delivery index of 500 mL/min per squared meter or higher. Postoperative analgesia was provided immediately after surgery by an infusion of 0.125% levobupivacaine and 20 μg/mL morphine in epidural/paravertebral infusion. Pain, rescue-analgesia consumption, arterial pressure, and heart rate were recorded at 6, 24, and 48 hrs after surgery. Administration of anesthesia and data collection were done by research staff blinded to the regional analgesia technique.

RESULTS

The groups did not differ significantly in heart rate, mean arterial blood pressure, or systemic vascular resistance indices. However, to maintain the targeted oxygen delivery index, a greater volume of colloid infusion and phenylephrine were required, respectively, in the epidural than in the paravertebral group (554 ± 50 vs 196 ± 75 mL, P = 0.04; and 40 ± 10 vs 17 ± 4 μg, P = 0.04). Pain intensity before and after respiratory physiotherapy as well as 24 hr rescue piritramide consumption was similar in the epidural (4.1 ± 3.1 mg) and the paravertebral (2.5 ± 1.5 mg) groups (P = 0.14). Systolic blood pressure after 24 and 48 hrs was lower in the epidural group.

CONCLUSIONS

Under the conditions of our study, continuous paravertebral block resulted in similar analgesia but greater hemodynamic stability than epidural analgesia in patients having thoracotomy. Paravertebral block also required smaller volume of colloids and vasopressors to maintain the target oxygen delivery index (DO2I).

Laparoscopy-assisted subtotal gastrectomy under thoracic epidural-general anesthesia leading to the effects on postoperative micturition

BACKGROUND

Recently, the laparoscopic surgical technique has been widely applied to major surgery as it can minimize surgical incision, reduce blood loss, and shorten hospital stay. In this study, we evaluated the effectiveness of the laparoscopic surgery on postoperative micturitional function in comparison to open surgery.

METHOD

Sixty patients undergoing subtotal gastrectomy were assigned to either laparoscopic (L group, n = 30) or open surgery (O group, n = 30) groups. The combined thoracic epidural-general anesthesia was performed on all patients, and epidural patient-controlled analgesia (PCA) using ropivacaine and sufentanil was maintained for two days following surgery. After surgery, visual analog pain score (VAS), levels of sensory and motor block, observer's assessment of alertness/sedation score (OAA/S), time to first flatus, ambulation and oral intake, and micturition function were assessed.

RESULTS

The L group showed much earlier ambulation, flatus and oral intake than the O group. Although the scores of VAS and OAA/S were not significantly different between the two groups, the micturition problem scores of the L group were lower than that of the O group (P < 0.05). All patients of the L group had no difficulty in self-voiding, whereas four patients in the O group required urinary catheterization on the first postoperative day (POD1).

CONCLUSIONS

Patients who underwent laparoscopic subtotal gastrectomy had a low incidence of micturitional problem and showed early recovery. Therefore, urinary catheterization on POD1 may not be a routine procedure for those who undergo laparoscopic subtotal gastrectomy under combined thoracic epidural-general anesthesia.

Using EEG to monitor anesthesia drug effects during surgery

The use of processed electroencephalography (EEG) using a simple frontal lead system has been made available for assessing the impact of anesthetic medications during surgery. This review discusses the basic principles behind these devices. The foundations of anesthesia monitoring rest on the observations of Guedel with ether that the depth of anesthesia relates to the cortical, brainstem and spinal effects of the anesthetic agents. Anesthesiologists strive to have a patient who is immobile, is unconscious, is hemodynamically stable and who has no intraoperative awareness or recall. These anesthetic management principles apply today, despite the absence of ether from the available anesthetic medications. The use of the EEG as a supplement to the usual monitoring techniques rests on the observation that anesthetic medications all alter the synaptic function which produces the EEG. Frontal EEG can be viewed as a surrogate for the drug effects on the entire central nervous system (CNS). Using mathematical processing techniques, commercial EEG devices create an index usually between 0 and 100 to characterize this drug effect. Critical aspects of memory formation occur in the frontal lobes making EEG monitoring in this area a possible method to assess risk of recall. Integration of processed EEG monitoring into anesthetic management is evolving and its ability to characterize all of the anesthetic effects on the CNS (in particular awareness and recall) and improve decision making is under study.