[Ephedrine reduces the pain from propofol injection]

Propofol is the most frequently used intravenous anesthetic today. One of its side effects is the pain on injection. Various methods such as adding lidocaine, cooling or warming and dilution of the propofol solution have been used for reducing the pain. However, each of these methods comes with a degree of failure. We designed this double-blinded randomized clinical trial to evaluate the effects of ephedrine of the injection pain caused by propofol. Fifty patients, between 20-60 years old and in the ASA physical status I and II, were enrolled in this experimental study and randomly divided into two equal groups. The basal vital signs for all patients were recorded, and 30 seconds prior to the induction of anesthesia, either 70 micro g/kg of ephedrine [study group] or an equal volume of normal saline [control group] was administered without premedication. Then, 20% of propofol was administered to each patient, and the pain intensity was measured and recorded by both the Verbal Rating Scale [VRS; grading 0-3] and Face Pain Scale [FPS; grading 1-6]. The remaining dose of propofol and atracurium were administered. Patients of two groups were similar with respect to age, sex, ASA status, and basal vital signs [P>0.05]. The mean degrees of pain severity, in the study and control group were 0.48 +/- 0.51 and 1.08 +/- 759 by VRS [P = 0.002], and 1.48 +/- 0.586 and 2.04 +/- 0.841 by FPS [P=0.009], respectively. Based on the results of the present study, also supported by other studies, it seems that administration of ephedrine prior to propofol is a suitable method for reduction of pain from propofol injection

[ effect of a single dose of gabapentin on the rate of consumption of propofol and remifentanil during total intravenous anesthesia]

Gabapentin [structural analog of GABA], is an antiepileptic drug that its preoperative administration results in postoperative pain reduction. Considering the hypnotic effect of propofol, which is mediated by its attachment to GABAA, this hypothesis was propounded that administration of gabapentin can probably decrease the need for propofol and remifentanil during total intravenous anesthesia. Fifty patients scheduled for elective laparoscopic cholecystectomy, were assigned into two equal groups [n=25] in this randomized double blinded clinical trial. Study group received oral gabapentin [1200mg], and control group received placebo 3hrs before operation. Premedication and induction of anesthesia were the same in all patients. For the maintenance of anesthesia, oxygen and nitrous oxide [50%-50% mixture] and propofol and remifentanil infusion were used. The rate of propofol infusion was adjusted to maintain BIS in the range of 40- 60, and dose of remifentanil adjusted to maintain hemodynamic variables in the range of +/- 20% of baseline values. At the end of anesthesia the duration of anesthesia and the total amount of propofol and remifentanil used for every patient were recorded. The demographic parameters were similar in both groups [p>0.05]. Doses of propofol and remifentanil used for study group were significantly lower than doses used for control group [p<0.01]. The mean values of baseline systolic, diastolic, mean arterial, heart rates and BIS in the study group were lower than the corresponding values in the control group [p<0.05]. This study showed that a single dose of gabapentin before operation can decrease the need for propofol and remifentanil in total intravenous anesthesia during laparoscopic cholecystectomy

[Evaluation of Intravenous ephedrine's effect on shortening the onset time of muscle relaxation of induced by atracurium]

Delayed onset time of neuromuscular blocking is one of the limitations of using nondepolarizing muscle relaxants for facilitation of endotracheal intubation. This double-blinded randomized clinical trial was designed with the presumption that ephedrine can increase cardiac index and muscle blood flow and therefore it may shorten the onset time of muscle relaxation by atracurium. Sixty patients, aged 18-60 yr, with ASA physical status I, II were randomly assigned into two equal groups. Baseline vital signs were recorded and then all patients received intravenous midazolam and fentanyl, as premedication. One minute before induction of anesthesia with propofol and atracurium, the experimental group received intravenous ephedrine 70 micro g/kg and control group received an equal volume of normal saline. Muscle relaxation was assessed by means of peripheral nerve stimulator, based on TOF pattern of stimulation on ulnar nerve. The time interval between atracurium injection and the absence of TOF response [TOF=0] was recorded in all patients. Using SPSS software, data were analyzed by means of student's t-test and Chi-square test. Demographic data and baseline vital signs were similar in both groups [p>0.05]. The mean time taken for onset of relaxation, needed for endotracheal intubation [from atracurium administration to the time of TOF =0], was less in study group compared to control group [185.1 +/- 21.59 vs. 258.43 +/- 20.63 seconds] which was statistically significant [p<0.001]. intravenous injection of ephedrine shortens the onset time of atracurium induced muscle relaxation which is similar to other nondepolarizing muscle relaxants, such as vecuronium and rocuronium

effect of addition of intravenous nitroglycerin to lidocaine for improvement of quality of intravenous regional anesthesia

Disadvantages of intravenous regional anesthesia [IVRA] include slow onset, poor muscle relaxation, tourniquet pain, and rapid onset of pain after tourniquet deflation. In this randomized, double-blind study, we evaluated the effect of addition of nitroglycerine [NTG] to lidocaine for improvement of IVRA. Forty six patients [20-50 yrs] were randomly assigned into 2 equal groups. Under identical conditions, the control group received 3 mg/kg of lidocaine 0.5% diluted with saline, and the study group received an additional 200 microgram NTG. Vital signs and tourniquet pain were measured on the basis of VAS score and recorded before applying tourniquet and 5, 10, 15, 20, and 30 min after administration of anesthetic solution. The onset of sensory and motor block was measured and recorded for all patients. Severity of pain was measured at 5 min, 2, 4, 6, 12, 24, hours after deflation of tourniquet and the total dosage of pethidin injected in the first 24 hours after operation was calculated. Sensory and motor block began more rapidly in study group than control group [2.61 vs. 5.09 and 4.22 vs. 7.04 min., respectively] [p<0.05]. Recovery from sensory and motor block and onset of tourniquet pain were delayed [7.26 vs. 3.43, 9.70 vs. 3.74 and 25 vs. 16.65min., respectively] [p<0.05]. Duration of analgesia after tourniquet deflation was more prolonged and tourniquet pain intensity was lower in study group [p<0.05]. Fentanyl requirement during operation and meperidine used during first postoperative day and pain intensity at 4, 6, 12 and 24hr postoperatively were lower in study group p<0.05. No significant side effect was noted in the patients of both groups. Addition of NTG to lidocaine in intravenous regional anesthesia accelerates the onset of anesthesia and decreases the tourniquet and postoperative pain, without any side effect

Evaluation of the effectiveness of lidocaine infusion in reduction of postoperative pain

Postoperative pain is an acute pain related to size and site of operation, patient's psychologic and physiological condition, degree of manipulation and damage of tissues. Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Administration of opioids is one of the common techniques for postoperative pain management, but complications related to opioids leads to use of other methods for pain control. In this study we evaluated the effect of low dose lidocaine infusion for postoperative pain control. In this study, 30 patients were randomized in two study and control groups under similar conditions. In study group, administration of lidocaine 1% [1.5mg/kg followed by 1.5 mg/ kg /h infusion] was started 30 minutes before operation, and continued 1 hour after operation. In control group, normal saline [placebo] was used. After 24 hours, pain of patients and systemic analgesic consumption was assessed and analyzed. Results showed that infusion of low dose lidocaine does not reduce postoperative pain and amount of morphine consumption 24 hours after operation. Difference in results of this study and other similar investigations can result from difference in design and selected surgical procedures. Also, lack of medical and research equipments such as appropriate PCA [Patient Controlled Analgesia] and measurement of blood levels of lidocaine were limitations of this study

High intravenous fluid therapy prevents post-tonsillectomy nausea and vomiting

Background: post-operative nausea and vomiting [PONV] following surgical operations requiring general anesthesia are common and distressing. The incidence of PONV may be as high as 70% during the first 24 hrs. of tonsillectomy

Objective: this study determines the effects of intraoperative well-hydration on postoperative nausea and vomiting

Methods: 90 ASA I patients with age of 6-12 years scheduled for tonsillectomy under general anesthesia randomly assigned to receive either routine iv fluid plus intraoperative well-hydration plus 4 ml/kg/h Ringer's solution [well hydrated group; n=45] and routine iv fluid requirements [control group; n=45]. All study preparations were administered in a double blinded fashion

Results: during the first postoperative day, the incidence of nausea and vomiting were significantly lower in the well-hydrated group as compared with control [p<0.05]. There was no significant differences between males and females regarding the incidence of nausea and vomiting [p>0.05]

Conclusion: the present study showed that well-hydration reduces the incidence of post tonsillectomy nausea and vomiting, and high iv fluid therapy is a simple, effective, safe and well-tolerated technique for prevention of postoperative nausea and vomiting