Sven-Egron Thörn

Low-dose bupivacaine plus fentanyl for spinal anesthesia during ambulatory inguinal herniorrhaphy: a comparison between 6 mg and 7. 5 mg of bupivacaine

Background: Inguinal herniorrhaphy is commonly performed as an outpatient procedure. Spinal anesthesia offers some advantages over general anesthesia in this setting.

Systemic and central effects of morphine on gastroduodenal motility

Gastrointestinal side effects still constitute a major drawback in both acute and chronic use of opioids. The exact mechanism behind the gastrointestinal effects is not known, but experimental studies indicate both central and peripheral actions.

Clonidine Combined with Small-Dose Bupivacaine During Spinal Anesthesia for Inguinal Herniorrhaphy: A Randomized Double-Blinded Study

The aim of this randomized double-blinded study was to see whether the addition of small-dose clonidine to small-dose bupivacaine for spinal anesthesia prolonged the duration of postoperative analgesia and also provided a sufficient block duration that would be adequate for inguinal herniorrhaphy. We randomized 45 patients to 3 groups receiving intrathecal hyperbaric bupivacaine 6 mg combined with saline (Group B), clonidine 15 &mgr;g (Group BC15), or clonidine 30 &mgr;g (Group BC30); all solutions were diluted with saline to 3 mL. The sensory block level was insufficient for surgery in five patients in Group B, and these patients were given general anesthesia. Patients in Groups BC15 and BC30 had a significantly higher spread of analgesia (two to four dermatomes) than those in Group B. Two-segment regression, return of S1 sensation, and regression of motor block were significantly longer in Group BC30 than in Group B. The addition of clonidine 15 and 30 &mgr;g to bupivacaine prolonged time to first analgesic request and decreased postoperative pain with minimal risk of hypotension. We conclude that clonidine 15 &mgr;g with bupivacaine 6 mg produced an effective spinal anesthesia and recommend this dose for inguinal herniorrhaphy, because it did not prolong the motor block.

Dexamethasone is as effective as ondansetron for the prevention of postoperative nausea and vomiting following breast surgery

Introduction:  Postoperative nausea and vomiting remain a common problem following breast surgery. This study assesses whether dexamethasone is as effective as ondansetron in the control of postoperative nausea and vomiting (PONV).

The influence of propofol on vomiting induced by apomorphine

It has been proposed that propofol has antiemetic effects even in nonsedative doses.The aim of this study was to investigate whether propofol influences vomiting induced by the dopamine agonist apomorphine. Ten healthy male volunteers received apomorphine infusion (1 mg/min) until vomiting was induced on four different occasions in a randomized order: a) during propofol infusion (2.4 +/- 0.7 mg centered dot kg (-1) centered dot h-1, mean +/- SD) at a sedation score of Grade 2-3 on a 5-grade scale; b) during midazolam infusion (0.13 +/- 0.04 mg centered dot kg-1 centered dot h-1) at a sedation score of Grade 2-3 on a 5-grade scale; c) after a single nonsedating bolus dose propofol 0.4 mg/kg; and d) during infusion of normal saline. The amount of apomorphine needed to induce vomiting was increased after sedation with propofol (P = 0.005) as well as midazolam (P = 0.001). There was no difference in the sensitivity to apomorphine between these sedative regimens. The nonsedating single bolus propofol did not change the sensitivity to apomorphine compared to the saline infusion. We conclude that propofol given in a nonsedative dose has no effect on apomorphine-induced vomiting. However, the total amount of apomorphine given to induce vomiting was significantly larger during propofol sedation than during saline infusion. This was probably an effect of sedation inasmuch as a similar result was achieved during midazolam sedation. (Anesth Analg 1995;80:967-9)

The effects of cricoid pressure, remifentanil, and propofol on esophageal motility and the lower esophageal sphincter.

Cricoid pressure is the gold standard during the induction of anesthesia when there is a risk of aspiration of gastric contents. However, the effect of cricoid pressure during the different steps of complete anesthesia induction has not been studied. The purpose of this study was to investigate the effects of cricoid pressure, remifentanil, and propofol on lower esophageal sphincter (LES) and esophageal motility. We recorded LES pressure (LESP) and calculated barrier pressure ([BrP] = LESP − gastric pressure) in 10 healthy volunteers using a Dent sleeve device. There was a significant decrease in LESP and BrP when a cricoid pressure of 30 N was performed in the awake volunteers (P < 0.05). However, this effect was not seen during the infusion of remifentanil 0.2 &mgr;g · kg−1 · min−1. Remifentanil per se or together with a bolus dose of propofol 1 mg/kg IV did not induce any statistical change in LESP or BrP. Remifentanil abolished spontaneous esophageal motility and completely eliminated the experience of discomfort induced by cricoid pressure. In conclusion, cricoid pressure of 30 N induced a decrease of LESP and BrP in awake volunteers. These effects were not seen during the remifentanil infusion. This shows the importance of when to apply cricoid pressure during rapid-sequence induction.

Propofol sedation and gastric emptying in volunteers

Background: The purpose of this study was to evaluate the effects of light propofol sedation on gastric emptying and orocecal transit time (OCT).

Propofol and gastric effects of morphine

Objective: The purpose of this study was to evaluate whether propofol abolishes morphine‐induced effects on gastric emptying and gastric tone.

Effects of pain stimulation on bispectral index, heart rate and blood pressure at different minimal alveolar concentration values of sevoflurane.

Background: The aim of the present study was to examine the level of unconsciousness measured with bispectral index (BIS) at different minimal alveolar concentration (MAC) levels of sevoflurane, and to study the hemodynamic and BIS reactions during noxious stimulation with transcutaneous electrical nerve stimulation (TENS) and an ice water pain test (IWP).

The delay of gastric emptying induced by remifentanil is not influenced by posture.

Posture has an effect on gastric emptying. In this study, we investigated whether posture influences the delay in gastric emptying induced by opioid analgesics. Ten healthy male subjects underwent 4 gastric emptying studies with the acetaminophen method. On two occasions the subjects were given a continuous infusion of remifentanil (0.2 μg · kg−1 · min−1) while lying either on the right lateral side in a 20° head-up position or on the left lateral side in a 20° head-down position. On two other occasions no infusion was given, and the subjects were studied lying in the two positions. When remifentanil was given, there were no significant differences between the two postures in maximal acetaminophen concentration (right side, 34 μmol · L−1; versus left side, 16 μmol · L−1), time taken to reach the maximal concentration (94 versus 109 min), or area under the serum acetaminophen concentration time curve from 0 to 60 min (962 versus 197 min · μmol · L−1). In the control situation, there were differences between the postures in maximal acetaminophen concentration (138 versus 94 μmol · L−1; P <0.0001) and area under the serum acetaminophen concentration time curves from 0 to 60 min (5092 versus 3793 min · μmol · L−1; P <0.0001), but there was no significant difference in time taken to reach the maximal concentration (25 versus 47 min). Compared with the control situation, remifentanil delayed gastric emptying in both postures. We conclude that remifentanil delays gastric emptying and that this delay is not influenced by posture.