T. Guler

The effect of pre-anaesthetic administration of intravenous dexmedetomidine on postoperative pain in patients receiving patient-controlled morphine

Background and objective: This prospective, randomized, double‐blind, controlled study was designed to test the effect of pre‐anaesthetic administration of dexmedetomidine, given as a single intravenous (i.v.) dose, on postoperative pain scores and morphine consumption in patients receiving patient‐controlled morphine after abdominal surgery. Methods: Sixty patients were randomly allocated to receive dexmedetomidine (1 μg kg−1) or saline 10 min before induction of anaesthesia. Twenty minutes before the end of surgery, all patients received a standardized (0.1 mg kg−1) loading dose of morphine. They were then allowed to use a patient‐controlled analgesia (PCA) device giving bolus doses of morphine (0.02 mg kg−1). Pain, discomfort and sedation scores; cumulative morphine consumption; time to extubation; time to recovery; and any side‐effects were recorded after recovery and at 1, 2, 6, 12 and 24 h after the start of PCA. Results: The mean time to extubation at the end of anaesthesia and recovery time were similar in both groups. There were no significant differences between groups with regard to mean pain, discomfort, sedation and nausea scores. Cumulative morphine consumption was significantly lower in the dexmedetomidine group at 6, 12 and 24 h (P < 0.05). The incidence of side‐effects did not differ between the groups. Conclusions: A single i.v. dose of dexmedetomidine (1 μg kg−1) given 10 min before induction of anaesthesia significantly reduced postoperative morphine consumption at identical pain scores compared to control, but had no effect on postoperative recovery time.

The effect of adding intrathecal magnesium sulphate to bupivacaine–fentanyl spinal anaesthesia

Background:  The addition of intrathecal (IT) magnesium to spinal fentanyl prolongs the duration of spinal analgesia for vaginal delivery. In this prospective, randomized, double‐blind, controlled study, we investigated the effect of adding IT magnesium sulphate to bupivacaine–fentanyl spinal anaesthesia.

Comparative study of the antiemetic efficacy of ondansetron, propofol and midazolam in the early postoperative period

Background and objective: To compare the antiemetic efficacy of ondansetron with two different hypnotic drugs (propofol 15 mg, midazolam 1 and 2 mg) for the treatment of established postoperative nausea and vomiting (PONV). Methods: Four-hundred-and-fifty-three patients scheduled for elective gynaecological or abdominal surgery were enrolled. One-hundred-and-twenty patients (26%) experienced postoperative emesis, and when nausea scores reached 2 or greater on a five-point scale, they were randomized to receive intravenously: propofol 15 mg (1.5 mL) in Group P, midazolam 1 mg in Group M1, midazolam 2 mg in Group M2 and ondansetron 4 mg in Group O. Results: Four patients (13.3%) in Group P, 13 patients (43.3%) in Group M1, five patients (16.6%) in Group M2 and one patient (3.3%) in Group O required a second dose of the study drug. After administration of the study drugs, nausea scores were significantly lower in all groups than before these drugs were given. No patient had a sedation score over 3 (the patients remained awake and/or responded to verbal contact). The sedative effects of midazolam and propofol lasted for a much shorter time than the antiemetic effects of these drugs. Conclusions: Propofol and midazolam used in subhypnotic doses were as effective as ondansetron in treating PONV in patients undergoing abdominal or gynaecological surgery without untoward sedative or cardiovascular effects.

Postoperative pain management with intravenous patient-controlled morphine: comparison of the effect of adding magnesium or ketamine.

Background and objective: This double‐blind randomized study tested whether the addition of magnesium or ketamine to morphine for intravenous patient‐controlled analgesia resulted in improved analgesic efficacy and lower pain scores compared with morphine patient‐controlled analgesia alone after major abdominal surgery. Methods: Ninety patients (3 × 30) were randomly allocated to receive either morphine 0.4 mg mL−1 (Group M) by patient‐controlled analgesia, morphine 0.4 mg mL−1 + MgSO4 30 mg mL−1 (Group MM) or morphine 0.4 mg mL−1 + ketamine 1 mg mL−1 (Group MK). Postoperative analgesia was started when the verbal rating scale was ≥2. Patients were first given a standardized loading dose (0.05 mg kg−1) of the study solution. They were then allowed to use bolus doses of this solution (0.0125 mg kg−1 every 20 min without time limit). Discomfort, sedation, pain scores, cumulative morphine consumption and adverse effects were recorded up to 24 h after the start of the patient‐controlled analgesia. Results: The level of discomfort, level of sedation and verbal rating scores decreased significantly with time in all groups (P < 0.05). Both verbal rating and discomfort scores were significantly lower in Groups MM and MK at 15, 30 and 60 min compared with Group M (P < 0.001). Cumulative morphine consumption after 12 and 24 h was significantly higher in Group M alone (median 26 and 49 mg, respectively) compared with Group MM (24.2 and 45.7 mg) and Group MK (24.4 and 46.5 mg). Conclusions: In the immediate postoperative period, the addition of magnesium or ketamine to morphine for intravenous patient‐controlled analgesia led to a significantly lower consumption of morphine. However, these differences are unlikely to be of any clinical relevance.

A background infusion of morphine enhances patient-controlled analgesia after cardiac surgery

PurposeWe compared the efficacy of patient-controlled analgesia (PCA), with or without a background infusion of morphine, on postoperative pain relief in patients extubated in the operating room after coronary artery bypass grafting (CABG) surgery.MethodsWith Faculty Ethics approval, 60 consenting adults undergoing elective coronary artery surgery were randomly assigned to receive either morphine PCA alone (group PCA-A,n = 30) or morphine PCA plus a background infusion (group PCA-B,n = 30) for 24 hr postoperatively Pain scores with verbal rating scale (VRS1 from 0 to 10) at rest, sedation scores, morphine consumption and delivery/demand ratios were assessed at zero, one, two, four, six, 12 and 24 hr after surgery. Hemodynamic variables and arterial blood gases were also recorded in the same periods.ResultsSedation scores in the two groups were similar. At all study periods after the first postoperative hour, VRS remained below 5 in both groups. Pain scores were significantly lower in the background infusion group, which also had greater cumulative morphine consumption (61.7 ± 10.9 mg vs 38.5 ± 16.2 mg). There were no episodes of hypoxemia or hypertension.ConclusionMorphine PCA effectively controlled postoperative pain after cardiac surgery. The addition of a background infusion of morphine enhanced analgesia and increased morphine consumption.RésuméObjectifNous avons comparé les effets de l’analgésie autocontrôlée (AAC), avec ou sans une perfusion de morphine de base, sur l’analgésie postopératoire des patients extubés au bloc opératoire à la suite d’un pontage aortocoronalre.MéthodeSoixante adultes consentants devant subir une opération de pontage aortocoronalre réglée ont été recrutés dans notre étude après l’accord du Comité d’Éthique de la Faculté. Les patients ont reçu soit de la morphine en AAC seule (Groupe AAC-A, n = 30), soit de la morphine en AAC plus une perfusion de base continue (Groupe AAC-B, n =30) pendant 24 h après l’opération. La douleur au repos selon une échelle verbale analogique (score de 0 à 10), les scores de sédation, la consommation de morphine, ainsi que les niveaux sérlques de morphine à zéro, une, deux, quatre, six, 12 et 24 h après l’opération ont été évalués. Le bilan hémodynamique et les gaz du sang ont aussi été enregistrés durant la même période.RésultatsIl n’y avait pas de différence dans les scores de sédation entre les deux groupes. Après la première heure postopératoire l’échelle verbale analogique était en dessous de 5 dans les deux groupes. Les scores de douleurs étalent slgnlfcatlvement moins élevés dans le groupe perfusion de base; ce dernier groupe avait aussi une plus grande consommation cumulative de morphine (61,7 ± 10,9 mgvs38,5 ± 16,2 mg). Il n’y a pas eu d’épisode d’hypoxle ni d’hypertension.ConclusionLAAC avec la morphine réduit efficacement la douleur postopératoire en cardiochirurgie. L’ajout d’une perfusion de base de morphine améliore l’analgésie et augmente la consommation de morphine.

Remifentanil produces vasorelaxation in isolated rat thoracic aorta strips.

Background: Remifentanil can cause transient instability in hemodynamic variables. However this change may not be solely the result of autonomic or central nervous system inhibition or of centrally mediated vagal stimulation. In this study, the aim was to examine the direct effects of remifentanil on isolated thoracic aorta strips in vitro.

Comparison of intrathecal magnesium, fentanyl, or placebo combined with bupivacaine 0.5% for parturients undergoing elective cesarean delivery

Background: Intrathecal (i.t.) administration of magnesium has been reported to potentiate opioid antinociception in rats and humans. In this prospective, randomized, double‐blind, study, we investigated the sensory, motor, and analgesic block characteristics of i.t. magnesium 50 mg compared with fentanyl 25 μg and saline when added to 0.5% bupivacaine (10 mg).

Remifentanil-induced mechanical responses and membrane potential changes in human umbilical arteries

Background:  The aim of this study was to evaluate the characteristic features of the mechanical responses and membrane potential changes induced by remifentanil in human umbilical arteries (HUAs). The ionic mechanisms underlying the electrophysiological responses were pharmacologically assessed using two K+ channel blockers.