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 microg and saline when added to 0.5% bupivacaine (10 mg). METHODS: Ninety ASA I or II adult patients undergoing cesarean section were randomly allocated to receive 1.0 ml of 0.9% sodium chloride in group S, 50 mg of magnesium sulfate (1.0 ml) 5% in group M, or 25 microg of fentanyl (1.0 ml) in group F following 10 mg of bupivacaine 0.5% i.t. We recorded the following: onset and duration of sensory and motor block, maximal sensory block height, the time to reach the maximal dermatomal level of sensory block, and the duration of spinal anesthesia. RESULTS: Magnesium did not shorten the onset time of sensory and motor blockade or prolong the duration of spinal anesthesia. The duration of sensory (P<0.032) and motor (P<0.002) blockade was significantly shorter in M and S groups than in the F group. The time to reach the maximal dermatomal level of sensory block was significantly shorter in the F group than in the S and M groups (P<0.002). CONCLUSION: In patients undergoing cesarean section with spinal anesthesia, the addition of magnesium sulfate (50 mg) i.t. to 10 mg of spinal bupivacaine (0.5%) did not shorten the onset time of sensory and motor blockade or prolong the duration of spinal anesthesia, as seen with fentanyl.

A randomized controlled study evaluating the effects of the temperature of insufflated CO2 on core body temperature and blood gases (an experimental study).

BACKGROUND: Heated carbon dioxide (CO2) was used for pneumoperitoneum (Pp) to prevent hypothermia. This study aimed to investigate the relationship between the temperature of the insufflated CO2 and blood gases together with the core body temperature (CBT). METHODS: A prospective controlled study was performed with 24 pigs weighing approximately 20 kg randomized into four groups of 6 pigs each. A pneumoperitoneum at 12 mmHg of pressure was applied for 60 min with the pig under general anesthesia. The CO2)temperature was 22 degrees C in group 1, 37 degrees C in group 2, and 7 degrees C in group 3. In the "sham" group, pneumoperitoneum was not applied. Arterial blood pH and partial pressure of CO2 (PaCO2) were analyzed before insufflation, every 15 min during the pneumoperitoneum, and 15 min after the desufflation. The CBT was recorded before the insufflation, every 20 min during pneumoperitoneum, and 20 min after the desufflation. Blood gas analyses and CBT records for the "sham" group were performed at the same intervals. RESULTS: Arterial blood pH gradually decreased during pneumoperitoneum. At the 60th minute of pneumoperitoneum, a minimum decrease in arterial blood pH (0.04; p = 0.027) and a minimum increase in PaCO2 (3.67; p = 0.027) were recorded in group 3, whereas a maximum decrease in arterial blood pH (0.18; p = 0.027) and a maximum increase in PaCO2 (17.17; p = 0.027) were recorded in group 2. There was a significant negative correlation between PaCO2 and arterial blood pH in all the groups (r = -0.993; p < 0.01). The mean values of CBT decreases were statistically significant in all the groups: group 1 (p = 0.023), group 2 (p = 0.026), group 3 (p = 0.026), and "sham" group (p = 0.024). CONCLUSIONS: The changes in PaCO2 were directly proportional and the changes in pH contrarily proportional to the temperature of the insufflated CO2. Significant differences in CBT decreases were found between the groups receiving heated gas and room temperature gas and the groups receiving heated gas and gas below room temperature.

A double-blind comparison of intrathecal S(+) ketamine and fentanyl combined with bupivacaine 0.5% for Caesarean delivery.

BACKGROUND: In this prospective, randomized, double-blind, controlled study, we investigated the sensory, motor and analgesic block characteristics of S(+) ketamine, fentanyl and saline given intrathecally (IT) in addition to 0.5% plain bupivacaine (10 mg) for spinal analgesia. METHODS: Ninety ASA I or II adult patients undergoing Caesarean section were randomly allocated to receive 1.0 mL of 0.9% saline in Group S (n = 30), 0.05 mg kg-1 of S(+) ketamine (1.0 mL) in Group K (n =30) or 25 microg (1.0 mL) of fentanyl in Group F (n =30) following 10 mg of plain bupivacaine 0.5% IT. We recorded onset and duration of sensory and motor block, time to reach the maximal dermatomal level of sensory block and duration of spinal analgesia. RESULTS: The onset time of sensory and motor block was significantly shorter in Groups K and F than in Group S (P < 0.014). Their duration was significantly longer in Group F than in Groups K and S (P < 0.009). The time to reach the maximal dermatomal level of sensory block was significantly shorter in Groups K and F than in Group S (P < 0.001). The duration of spinal analgesia was significantly longer in Group F than in Groups K and S (P < 0.001). CONCLUSION: In patients undergoing Caesarean section with spinal analgesia, the addition of S(+) ketamine (0.05 mg kg-1) IT to 10 mg of spinal plain bupivacaine (0.5%) led to rapid onset of both sensory and motor blockade and enhanced the segmental spread of spinal block without prolonging the duration of spinal analgesia, whereas fentanyl provided prolonged analgesia.

Comparison of caudal ketamine with lidocaine or tramadol administration for postoperative analgesia of hypospadias surgery in children.

BACKGROUND: This study was designed to investigate whether the addition of tramadol or lidocaine to ketamine would enhance the quality of intra- and postoperative analgesia for hypospadias surgery in children. METHODS: Sixty-two ASA PS I or II children, between 1 and 10 years of age, scheduled for hypospadias surgery were recruited. Anesthesia was induced with 6-8% sevoflurane and maintained with 0.5-2.5% sevoflurane-50% N2O in oxygen. Children were allocated randomly to receive one of two study drugs. Children in group KL received caudal ketamine (0.25 mg.kg(-1)) plus lidocaine (2%, 2 mg.kg(-1)) and in group KT ketamine (0.25 mg.kg(-1)) plus tramadol (1 mg.kg(-1)). Systemic blood pressure, heart rate, peripheral O2 saturation, sedation, and pain scores (CHEOPS) were recorded at 1, 5, 10, 15, 30, 45 min and 1, 2, 3 h following recovery from anesthesia. RESULTS: Duration of analgesia was similar in the two groups (P > 0.05). CHEOPS in group KL was lower than in group KT during the study period, except at first 15 min. Sedation scores were higher in group KL than group KT in the first 10 min (P < 0.05). Incidence of postoperative nausea and vomiting was similar in the two groups (P > 0.05) Sevoflurane concentration required was significantly lower in group KL than group KT peroperatively (P < 0.001). CONCLUSIONS: Caudal ketamine (0.25 mg.kg(-1)), plus lidocaine (2% 2 mg.kg(-1)) significantly reduced sevoflurane concentration compared with ketamine (0.25 mg.kg(-1)) + tramadol (1 mg.kg(-1)). We suggested that both ketamine + lidocaine and ketamine + tramadol provided very effective and long duration of analgesia, similarly. However, analgesia quality is superior in the ketamine-lidocaine group postoperatively.

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. METHODS: One hundred and two ASA I or II adult patients undergoing lower extremity surgery were recruited. They were randomly allocated to receive 1.0 ml of preservative-free 0.9% sodium chloride (group S) or 50 mg of magnesium sulphate 5% (1.0 ml) (group M) following 10 mg of bupivacaine 0.5% plus 25 microg of fentanyl intrathecally. We recorded the following: onset and duration of sensory block, the highest level of sensory block, the time to reach the highest dermatomal level of sensory block and to complete motor block recovery and the duration of spinal anaesthesia. RESULTS: Magnesium caused a delay in the onset of both sensory and motor blockade. The highest level of sensory block was significantly lower in group M than in group S at 5, 10 and 15 min (P < 0.001). The median time to reach the highest dermatomal level of sensory block was 17 min in group M and 13 min in group S (P < 0.05). The mean degree of motor block was also lower in group M at 5, 10 and 15 min (P < 0.001). The median duration of spinal anaesthesia was longer in group M (P < 0.001). CONCLUSION: In patients undergoing lower extremity surgery, the addition of IT magnesium sulphate (50 mg) to spinal anaesthesia induced by bupivacaine and fentanyl significantly delayed the onset of both sensory and motor blockade, but also prolonged the period of anaesthesia without additional side-effects.

A comparative study of continuous positive airway pressure (CPAP) and intermittent positive pressure ventilation (IPPV) in patients with flail chest.

INTRODUCTION: The role of non-invasive positive pressure ventilation delivered through a face mask in patients with flail chest is uncertain. We conducted a prospective, randomised study of continuous positive airway pressure (CPAP) given via a face mask to spontaneously breathing patients compared with intermittent positive pressure ventilation (IPPV) with endotracheal intubation (ETI) in 52 patients with flail chest who required mechanical ventilation. METHOD: The 52 mechanically ventilated patients were randomly divided into two treatment groups: the ET group (n = 27) received mechanical ventilation with ETI, whereas patients in the CPAP group (n = 25) received CPAP via a face mask with patient controlled analgesia (PCA). Major complications, arterial blood gas levels, length of intensive care unit (ICU) stay and ICU survival rate were recorded. RESULTS: Nosocomial infection was diagnosed in 10 of 21 patients in the ET group, but only in 4 of 22 in the CPAP group (p = 0.001). Mean PO(2) was significantly higher in the ET group in the first 2 days (p<0.05). There were no significant differences in length of ICU stay between groups. Twenty CPAP patients survived, but only 14 of 21 intubated patients who received IPPV (p<0.01). CONCLUSION: Non-invasive CPAP with PCA led to lower mortality and a lower nosocomial infection rate, but similar oxygenation and length of ICU stay. The study supports the application of CPAP at least as a first line of treatment for flail chest caused by blunt thoracic trauma.

Pre-emptive analgesic efficacy of tramadol compared with morphine after major abdominal surgery.

BACKGROUND: Studies of pre-emptive analgesia in humans have shown conflicting results. This prospective, randomized, double-blind, controlled study was designed to test the hypothesis that a reduction in postoperative morphine consumption can be achieved by tramadol administered after induction of anaesthesia. METHODS: Ninety patients were allocated randomly to receive i.v. tramadol (1 mg kg(-1)) (Group T), morphine (0.1 mg kg(-1)) (Group M) or saline 2 ml (Group S) after induction of anaesthesia. At peritoneal closure, a standardized (0.1 mg kg(-1)) morphine loading dose was given to all patients for postoperative pain management. Patients were allowed to use a patient-controlled analgesia (PCA) device giving bolus doses of morphine 0.025 mg kg(-1). Discomfort, sedation, pain scores, cumulative morphine consumption, and side-effects were recorded at 1, 2, 6, 12 and 24 h after the start of PCA. RESULTS: There were no significant differences between groups in mean pain, discomfort, and sedation scores at any study period. Cumulative morphine consumption was significantly lower in Group M at 12 and 24 h after starting the PCA than in Group S. In Group T, it was lower only after 24 h (28% less in Group M and 17% less in Group T; P<0.017). There were no significant differences in morphine consumption between Groups T and M. CONCLUSIONS: Tramadol (1 mg kg(-1)), administered after induction of anaesthesia, offered equivalent postoperative pain relief, and similar recovery times and postoperative PCA morphine consumption compared with giving morphine 0.1 mg kg(-1). These results also suggest that presurgical exposure to systemic opioid analgesia may not result in clinically significant benefits .

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. METHOD: Ninety patients (3 x 30) were randomly allocated to receive either morphine 0.4 mg mL(-1) (Group M) by patient-controlled analgesia, morphine 0.4mg mL(-1) + MgSO4 30mg 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 > or = 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.

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. METHODS: Forty-five Wistar rat thoracic aorta rings were isolated, and contraction-relaxation responses were recorded. RESULTS: In aortic rings precontracted with phenylephrine or potassium chloride, remifentanil produced concentration-dependent relaxation in both endothelium-intact and denuded rings (P<0.001). Remifentanil induced significantly greater relaxation in intact rings than in those denuded of endothelium, regardless of whether they were precontracted with phenylephrine hydrochloride or KCl (P<0.001). When the endothelium was present, remifentanil produced greater relaxation in KCl-contracted rings than in PE-contracted rings at lower concentrations (10-9 and 10-8), and similar relaxation at higher concentrations (10-7 and 10-6). However, when the endothelium was removed, relaxation was similar in both solutions, at all concentrations (10-9 to 10-6). In intact rings, pretreatment with L-NO-ARG or indomethacin reduced the degree of remifentanil-induced relaxation. In Ca+ +/- free media, calcium-dependent KCl contractions were inhibited in a dose-dependent manner by remifentanil (P<0.001). CONCLUSION: Remifentanil vasodilates by an endothelium-dependent mechanism, involving prostacyclin and nitric oxide released from the endothelium. Its endothelium-independent vasodilation probably occurs via the suppression of voltage-sensitive Ca++ channels.

A comparative study on the analgesic effect of tramadol, tramadol plus magnesium, and tramadol plus ketamine for postoperative pain management after major abdominal surgery.

BACKGROUND: We tested whether, after major abdominal surgery, the addition of magnesium or ketamine to tramadol for intravenous (IV) patient-controlled analgesia (PCA) improved analgesia and lowered pain scores, compared to a PCA containing only tramadol. METHODS: Sixty-six patients were allocated randomly to receive a PCA with tramadol alone (T), tramadol plus magnesium (TM) or tramadol plus ketamin (TK), in a double-blind randomized study. Postoperative analgesia was started when the verbal rating scale (VRS) score was 2 or more. Following a loading dose of the study solution (which contained 1 mg/kg tramadol), a background infusion of 0.4 mg/kg/h was started. Patients were allowed to use bolus doses of 0.2 mg/kg every 20 min without a time limit. Discomfort, sedation, pain scores, total and bolus PCA tramadol consumption, and side-effects, were recorded for up to 24 h after the start of PCA. RESULTS: Pain and discomfort scores were lower (P < 0.01) in groups TM and TK at 15, 30, 60 and 120 min than in group T. The addition of magnesium or ketamine significantly reduced the consumption of tramadol at 6, 12 and 24 h (P < 0.01). The incidence of nausea did not differ between the groups. CONCLUSION: Adding magnesium or ketamine to tramadol improved analgesia and patient comfort and decreased the amount of tramadol required for postoperative pain management after major abdominal surgery.