Comparison of ondansetron and meperidine for treatment of postoperative shivering: a randomized controlled clinical trial.

BACKGROUND: The involved neurotransmitter pathways in the postoperative shivering (POS) are poorly understood. Recently, 5-hydroxytryptamine 3 (5-HT3) receptor antagonists have been reported to prevent POS. We investigated the effect of ondansetron, a 5-HT3 antagonist that is used to treat postoperative nausea and vomiting, on shivering. OBJECTIVES: This study aimed to compare the efficacy of ondansetron and meperidine in the treatment of shivering after general anesthesia. PATIENTS AND METHODS: In this double-blinded randomized clinical trial, 83 patients (age range, 18-60 years) who had shivering after general anesthesia were randomly allocated to any of these three groups: Group A, (number = 27) received 4 mg of intravenous ondansetron, Group B, (number = 27) received 8 mg of intravenous ondansetron, and Group C, (number = 29) received 0.4 mg/kg of intravenous meperidine at recovery room. The surface temperatures and the incidence as well as intensity of shivering were recorded. RESULTS: Shivering was controlled in 16 patients (59%) in Group A, 22 (81%) in Group B, and 25 (86%) in Group C (P = 0.01). Within each group, there were no significant differences among the surface temperature in recovery room. Patients in groups A and B had significantly lower incidence of nausea and vomiting than group C (P = 0.01). CONCLUSIONS: Ondansetron and meperidine have similar effects on shivering. We concluded that 8 mg of intravenous ondansetron can control shivering and this is the dose of choice, especially in patients with POS with nausea and vomiting.

The effect of low-dose remifentanil on the hemodynamic responses of endotracheal extubation.

Emergence from general anesthesia can be associated with coughing, agitation, and hemodynamic disturbances. Remifentanil may attenuate these responses. We have examined the effect of remifentanil on the hemodynamic response to the emergence from anesthesia and tracheal extubation. In a double-blind, randomized trial, we enrolled 50 adult patients undergoing abdominal surgery. All patients received a standard general anesthetic comprising propofol, atracurium and 1% isoflurane with 50% nitrous oxide in oxygen. At the end of surgery, a bolus dose of remifentanil 0.2 microgram/kg (n = 25) or saline placebo (n = 25) was given and tracheal extubation was performed when standard criteria were achieved. Arterial pressure and heart rate were measured non-invasively, immediately after tracheal extubation and then at 1-min intervals. Remifentanil attenuated the increase in both systolic and diastolic arterial pressure and heart rate after extubation compared to the control group. No differences in SpO2, cough and laryngospasm were observed between two groups. Use of a low-dose remifentanil has clinically acceptable effect in blunting the cardiovascular changes induced by tracheal extubation.

Comparing the effect of pregabalin, gabapentin, and acetaminophen on post-dural puncture headache.

INTRODUCTION: Post-dural puncture headache (PDPH) is a common complication of lumbar puncture for any purpose. To avoid the need for invasive methods of treating PDPH such as blood patch, the search for novel pharmacological agents to manage PDPH continues. The aim of this study was to compare the effects of acetaminophen, gabapentin and pregabalin in controlling PDPH in patients who underwent surgery under spinal anesthesia. MATERIALS AND METHODS: A total of 90 patients who underwent elective orthopedic surgery under spinal anesthesia and suffered from PDPH consequently were enrolled in this randomized trial. Patients were categorized randomly into three groups. Group A, B and C have received Acetaminophen, Gabapentin and Pregabalin (3 times a day for 3 days), respectively. The effect of medications on the severity of PDPH was evaluated and compared using visual analog scale (VAS). RESULTS: The mean VAS score was significantly lower in pregabalin group compared with others 24, 48 and 72 h after the onset of headache (P = 0.001 for all of them) and lower in Gabapentin group compared with Acetaminophen group 24, 48 and 72 h after the onset of headache (P = 0.001 for all analyses). No adverse outcome was reported in groups. CONCLUSION: Pregabalin and gabapentin are both useful and safe in management of PDPH, but pregabalin is more effective in this regard.

The effect of pre-operative administration of gabapentin on post-operative pain relief after herniorrhaphy.

BACKGROUND: Gabapentin, an anticonvulsant, recently has been suggested as an effective post-operative "analgesic" agent. The objective of the present study was to examine the analgesic effectiveness and opioid-sparing effects associated with the use of a single dose of gabapentin as a prophylactic analgesic. MATERIALS AND METHODS: In a randomized double-blinded clinical trial, 50 American Society of Anesthesiologists I and II patients with an age range of 40-60 years who were the candidate for inguinal herniorrhaphy under spinal anesthesia were randomly assigned to receive 400 mg gabapentin or placebo 2 h prior to surgery. Post-operatively, the pain was assessed on a visual analog scale (VAS) at 2, 4, 12 and 24 h at rest. Morphine 0.05 mg/kg intravenously was used to treat post-operative pain on patient's demand. Total morphine consumption in the first 24 h after surgery was also recorded. RESULTS: Patients in the gabapentin group had significantly lower VAS scores at the all-time intervals of study than those in the placebo group (P < 0.05). The total morphine consumption in the first 24 h after surgery was also significantly lower in gabapentin group than in the placebo group (0.9 ± 1.23 vs. 1.8 ± 1.5; P = 0.003). There was no significant difference between the first time of analgesic request among the two groups. CONCLUSION: In conclusion, prophylactic administration of gabapentin decreases pain scores and analgesic consumption in the first 24 h after repair of inguinal hernia.

The effect of acupressure on nausea and vomiting after cesarean section under spinal anesthesia.

Postoperative nausea and vomiting (PONV) is one of the most common postoperative complications. Aside from pharmacological interventions, other complementary healing modalities have been introduced to assist patients in decreasing PONV and improving postoperative outcomes. This study examined acupressure as a safe complement to the more traditional approach of using drugs to prevent and/or relieve nausea and vomiting in the Cesarean section (C/S) under spinal anesthesia. In a prospective randomized clinical trial, 152 patients who were candidate for elective C/S under spinal anesthesia were evaluated in two groups (acupressure vs control groups). Subjects in the acupressure group received constant pressure by a specific wrist elastic band (without puncture of the skin) on the Nei-Guan acupuncture point, 30 min prior to spinal anesthesia. The incidence of PONV was assessed during the surgery, at recovery room and at 1st, 2nd and 3rd two hours after the surgery. Significant differences in the incidence of the post-operative nausea and vomiting were found between the acupressure and control groups, with a reduction in the incidence rate of nausea from 35.5% to 13.2%. The amount of vomitus and the degree of discomfort were, respectively, less and lower in the study group. In view of the total absence of side-effects in acupressure, its application is worthy. Our study confirmed the effectiveness of acupressure in preventing post-operative nausea and vomiting, when applied 30 minutes prior to surgery.

Theophylline versus acetaminophen in the treatment of post-dural puncture headache (PDPH).

BACKGROUND: Post-dural puncture headache (PDPH) is the most frequent complication of procedures associated with dural puncture for spinal anesthesia or following accidental dural puncture during epidural anesthesia. Since invasive treatments have known complications, pharmacologic management may be preferable. The aim of this study was to evaluate and compare the efficacy of theophylline and Acetaminophen in treatment of PDPH. METHODS: In this single-blind randomized clinical trial, 60 patients with Class I physical status according to ASA classification system, who suffered from PDPH were enrolled. Patients in Theophylline group were received theophylline tablet 250 mg three times per day, and in the other group acetaminophen 500 mg three times per day was administered. Pain intensity was assessed 2, 6, and 12 hour after drug administration using 0-10 cm Visual Analog Scale. RESULTS: The main VAS values is significantly lower in theophylline group in comparison with the acetaminophen group at 2 (5 +/- 1.57 vs. 5.97 +/- 1.27), 6 (3.43 +/- 1.73 vs. 4.33 +/- 1.49), and 12 (2.67 +/- 2.35 vs. 4.24 +/- 1.97) hours after drug administration (p < 0.05). No adverse effects were reported. DISCUSSION: Theophylline is a safe and effective treatment for PDPH. It may be tried in PDPH patients before using any invasive technique. Further investigations studying other Methylxanthines are recommended as well.

Intraoperative minimal acute normovolemic hemodilution in patients undergoing coronary artery bypass surgery.

BACKGROUND & OBJECTIVE: Efficacy of minimal acute normovolemic hemodilution (ANH) in avoiding homologous blood transfusion during cardiovascular surgery remains controversial. Postoperative bleeding and transfusion remain a source of morbidity and cost after open heart operations. Our objective was to evaluate the impact of minimal ANH on blood transfusion requirements during open cardiovascular surgery using cardiopulmonary bypass (CPB). METHODS: This study was a randomized controlled trial. One hundred one patients scheduled for elective coronary artery bypass graft (CABG) under cardiopulmonary bypass in October 2007 through March 2008 in Imam Khomeini hospital were randomly assigned to a control group (standard care, no = 47) or an ANH or study group (no = 54). We used minimal ANH (representing 10% of patients' blood volume). Mean 490 +/- 50 mL of fresh autologous blood was removed after induction of anesthesia and reinfused at the end of CPB. The blood transfusion guidelines were uniformly applied to all patients. RESULTS: Significant decrease in the number of red blood cell units transfused per patient per group (1.39 +/- 1.0 and 2.551.9 +/- units; p < 0.0001) in the ANH group versus the control group was observed. Conversely, chest tube output, postoperative hematocrits, and platelet count did not differ between two groups. Percentage of patients in whom allogeneic red blood cells were transfused was 44% in study group versus 76% in control group; (p < 0.01). No patient was transfused with platelet concentrates or fresh frozen plasma. CONCLUSIONS: Minimal ANH is safe and cost effective and its routine use in eligible patients is therefore justified. Intraoperative autologous blood donation in CABG surgery decreased perioperative allogeneic blood requirement. However, the removal and reinfusion of about one unit autologous blood had no effect on postoperative bleeding or platelet count.

Use of ketamine in severe status asthmaticus in intensive care unit.

Bronchial asthma represents an increased airways responsiveness to various stimulants, leading to reversible obstruction of expiratory flow and chronic inflammatory changes in airways wall. Ketamine has been demonstrated to lower airway resistance and to increase lung compliance in the asthmatic patients. In several studies and case reports it has been used successfully in the management of status asthmaticus, resistant to conventional therapy, but so far no clinical trial has been carried out to support this empirical use of ketamine. For this reason, we designed a prospective observational study.Eleven, 15-40 years old patients, with status asthmaticus whose respiratory failure did not respond to conventional therapy and mechanical ventilation (after 24h), were entered in this study (provided that there were not any contraindications to ketamine use). These patients received ketamine at a loading dose of 1 mg/kg (IV), followed by a continuous infusion of 1 mg/kg/hr for 2h. Peak airway pressure, PaCO2 and PaO2 were measured prior to ketamine administration, 15min after administration and 2h after infusion of ketamine. Mean peak airway pressure and PaCO2 significantly decreased 15min and 2h after administration and infusion of ketamine (p<0.005) and PaO2 significantly increased in these time intervals (p<0.005).Ketamine is a useful and safe drug in the intensive treatment of status asthmaticus. However, ketamine should only be used for asthmatics whose respiratory failure does not respond to standard therapy.