Effect of pretreatment with intravenous lidocaine and magnesium sulfate on onset and duration of rocuronium

Rocuronium is a steroidal non - depolarizing muscle relaxant that provides rapid onset with intermediate duration of action [1-5] Many drugs have been used to make its onset of action as short as that of succinyl choline[7, 8] The aim of this study is to evaluate the relaxant efficacy of low dose rocuronium 0.6 mg/kg either alone or pretreated with lidocaine 1.5 mg/kg or magnesium sulfate 30 mg/kg. Their effects on the time of onset and time of recovery [duration] of rocuronium muscle blockade and on the intubation conditions were assessed. A prospective randomized double blind clinical study was conducted on 75 ASA I and II adults undergoing short elective surgical procedures requiring tracheal intubation. They were divided into three groups 25 in each. In group I rocuronium was pretreated with normal saline. In patients of group II, rocuronium was pretreated with 1.5 mg/kg lidocaine. In group Ill, the patients were given 30mg/kg magnesium sulfate as pretreatment 3 minutes before rocuronium. Rocuronium was given in a dose of 0.6 mg /kg. The response of the adductor pollicis muscle of the non - dominant hand to train of four stimulation of the ulnar nerve at the wrist at 10 watch SX seconds intervals was measured using TOF watch [acceleromyography principle]. The mean onset time to T[1]= 25% and to complete disappearance of TOF trace [T[1]=0%] were measured [seconds]. All patients were intubated when T[1]=25% and intubation conditions were assessed on a four point scale as excellent, good, poor or inadequate according to the method described by Goldberg, et at., [12] [table I]. The mean times to initial recovery T[1]=10% and, clinical recovery, TOF ratio 75% were also measured. The mean onset time of rocuronium to T[1]= 25% and T1-0% were equally reduced by lidocaine in group II and magnesium sulfate in group Ill if compared with group I [control or saline]. Iidocaine pretreatment [group II] gave as excellent acceptable intubation scores as magnesium pretreatment [group III]. Intubation scores in groups II and m were statistically superior to those in group I - As regard recovery the mean times to initial recovery [T[1]=10%] and clinical recovery [TOF ratio 75%] were not affected by lidocaine while they were prolonged by magnesium sulfate. rocuronium [low dose] -lidocaine combination may be a safe alternative in rapid tracheal intubation of patients when succinyl choline is contraindicated especially when the surgery is of short duration. We recommend strict monitoring of neuromuscular block and titration of the dose of non - depolarizing muscle relaxants in patients on magnesium therapy

Effect of different esmolol doses on propofol required for induction of anesthesia

Esmolol a short acting beta[1]-receptor antagonist is known to reduce the cardiac output [CO]. Preinduction CO is a significant predictor for propofol dose required for induction of anesthesia. This study was designed to determine the effect of esmolol dose on propofol required for induction of anesthesia. Eighty patients were randomly allocated to placebo group I [saline] and esmolol groups Il, Ill, IV received esmolol bolus doses 0.5, 1 and 1.5 mg/kg respectively followed by i.v. infusion of 250 micro g/kg/min. After 5 minutes anesthesia was induced by propofol 10 mg/mI at 10 ml/min by infusion pump, the primary end point used was the propofol dose/kg at loss of response to command and duration of induction were recorded. CO, BP [Blood Pressure], HR [Heart Rate] and SpO[2]% saturation were monitored non-invasively. CO was measured before and after esmolol injection [at preinduction time]. Esmolol doses 0.5, 1 and 1.5 mg/kg. followed by esmolol infusion significantly reduced CO by 12%, 14.6% and 18.9% and reduced propofol dose required for induction of anesthesia by 15.3%, 23.38% and 3.6% from placebo group respectively. in addition the duration of induction was reduced significantly in group II, Ill and IV by 12.5%, 22.5% and 32.1% from placebo [group I] respectively in the same order. Esmolol dose reduced propofol induction dose and duration of induction of anesthesia in an inversely proportional manner possibly due to the effect of esmolol dose on preinduction cardiac output [CO]

Assessment of the efficacy of intravenous propactamol versus morphine in reducing post operative pain and vomiting in paediatric strabismus surgery

Post operative pain has been considered to be a major cause of post operative vomiting after corrective strabismus surgery in children 1. Many factors are known to influence the incidence of pain and vomiting in paediatric strabismus surgery including the use of opioid analgesia, the use of antiemetics, and anaesthetic technique. There has been an increasing interest in the use of propacetamol, an injectable water soluble prodrug of paracetamol [acetaminophen] which can be parenterally administered as analgesic for the treatment of post operative pain 2. This study was designed to assess the efficacy of injectable propacetamol versus morphine in reducing post operative pain and vomiting in paediatric strabismus surgery. After approval of our local ethical committee and obtaining written informed consents from the parents, 60 ASA I, II children 4-16 ys of age were included in our study. The study was conducted in a double blind randomized fashion. The children were randomly divided into 2 equal groups. Group I: Patients received propacetamol in 30 mg/kg/dose as l.V in fission. Group II: Patients received morphine in 0.1 mg/kg/dose. Anaesthesia was induced and maintained with propofol. Pain was assessed every 20 minutes on arrival to PACU using pain behaviour score. Incidence of postoperative vomiting was assessed by measuring the frequency of vomiting [0-2 h, 2-6 h, 6-24h]. Cortisol and epinephrine plasma levels were evaluated before the start of surgery and 2 hours post operative to assess the efficacy of propacetamol in obtunding hormonal stress response. In the propacetamol group I the incidence of vomiting during the first 24h was 16.6% [of which one child had severe vomiting]. The incidence of post operative vomiting in morphine group II was much higher 80% [P<0.01]. There was no difference as regards pain score between the two groups. Also, there was no statistical significant difference as regards the rise of post operative [2 h after operation] plasma level of cortisol and epinephrine between the 2 groups [p >0.05 = non significant]. No adverse effects were observed on using propacetamol. Propacetamol parenterally administered is an effective safe analgesic for paediatric strabismus surgery and gives less post operative vomiting than morphine i.v

comparative study between lidocaine iontophoresis, intravenous lidocaine, and magnesium sulfate pretreatment for reduction of pain during propofol injection

Propofol produces anesthcsia with rapid recovery[1]- It has become the induction agent of choice for elective surgery in many countries. However, it causes pain or discomfort on intravenous injection in 28 - 90% of patients, which is a recognized complication that is recalled post operatively by 52-62% of those who experience it, and several methods have been advocated to reduce its incidence and severity [2]. The aim of the study is to compare the efficacy of three different techniques in attenuating pain induced propofol injection, which are magnesium sulfate pretreatment prior to propofol administration, in comparison to iontophoretically applied lidocaine, which is a transdermal anesthesia technique and i.v. injection of 2% lidocaine prior to propofol injection. A prospective, randomized double blind clinical study was conducted in 90 ASA I and II adults undergoing elective surgery. After obtaining a written informed consent, they were divided into 3 groups 30 patients in each. Group I [lidocaine group] pretreated with 2 ml. 2% lidocaine [40 mg], the pretreatment injection given over 30 seconds, 1 minute before the start of propofol infusion. This is accompanied by venous occlusion for 1 min.In group II [lontophoresis group], the negative electrode containing 4% lidocaine in a hydrogel was placed on the test area on the dorsum of the hand while, the positive electrode was placed 10 cm proximally, and both electrodes were connected to the iontophoresis unit [lomed Phoresor 11, Croydon, UK]. Electric current was set at 0.0 mA and was increased gradually to a maximum 4.0 mA. lontophoresis was discontinued when 40 mA min-1 dose was delivered and the time required was recorded, since, drug delivery is proportional to the total electrical charge, measured as a product of the current strength and duration of application [units: miliampere x minutes, [mA.min-[1]][3]. In group III was pretreated with 2ml 50% magnesium sulfate [1 g] the pretreatment solutions were given over 30 seconds. 1 minute before the start of propofol infusion-This is accompanied by venous occlusion for 1 min. followed by propofol infusion. The infusion was stopped when the patient lost consciousness as detected by loss of eye lash reflex. Pain was assessed on a four point scale 0 = no pain, 1 = mild pain, 2 = moderate pain, 3= severe pain, at the start of propofol infusion and at 20 seconds intervals for 1 minute. The incidence of pain following i.v injection of propofol after pretreatment with lidocaine 2% was 17%in group I [lidocaine] compared to 39% and 46% in group II [lontophoresis] and group III [magnesium] respectively [P < 0.05]. Intravenous lidocaine pretreatment was more effective in attenuating pain during propofol administration than iontophoretically applied lidocaine and magnesium sulfate pretreatment. There was no statistically significant difference between group II and group Ill as regard pain reduction during propofol injection. intravenous lidocaine pretreatment is more effective in attenuating pain induced by propofol injection than topically applied lidocaine and magnesium sulfate pretreatment