OESOPHAGEAL CONTRACTILITY DURING TOTAL I.V. ANAESTHESIA WITH AND WITHOUT GLYCOPYRRONIUM

Somatic movement and spontaneous and provoked oesophageal contractionswere noted at time of incision in 51 patients receiving totali.v. anaesthesia with alfentanil and propofol. Probit analysisof the dose of propofol required to prevent spontaneous movementrevealed an ED₅₀ (95% confidence limits) of 2.5 (1.8-2.9) mgkg^–1 h^–1 and ED₉₅ of 4.7 (4.0-7.5) mg kg^–1h^–1. Corresponding venous blood concentrations gave anEC₅₀ of 1.2 (0.4-1.6) µg ml^–1 and an EC₉₅ of 4.0(2.8-18.5) µg ml^minus;1. ED₅₀ of propofol for preventingspontaneous oesophageal contraction was 3.0 (1.9-3.6) mg kg^–1h^–1. ED₉₅ was 6.9 (5.0-27.3) mg kg^–1 h^–1;EC₅₀ for oesophageal contractions was 1.7 (0.7-2.3) µgml^–1 and EC₉₅ was 5.9 (3.7-70.6) µg ml^–1.Another group of 10 patients were given glycopyrronium 5 µgkg^–1 at induction; oesophageal contractility was significantlyreduced in this group. Preliminary results of this research were presented to the AnaestheticResearch Society, Nottingham, July 1990. ^*Department of Anaesthesia, Derriford Hospital, Plymouth, DevonPL6 8DH. Department of Anaesthesia, Darlington Memorial Hospital, Darlington,Durham DL3 6HX.     

OUTCOME AFTER GENRAL ANAESTHESIA FOR REPAIR OF FRACTURED NECK OF FEMUR: A Randomized Trial of Spontaneous V. Controlled Ventilation

One hundred and fifty-two patients undergoing surgery for fracturedneck of femur were randomly allocated to receive either generalanaesthesia with spontanoeous ventilation with nitrous oxideand halothane in oxygen or general anaesthesia with controlledventilation with fentanyl, nitrous oxide and halothane in oxygen.Atracurium was used to provide muscle paralysis in 65% of thelatter group, the remained receiving no neuromuscular blockingagent other than suxamethonium for intubation. Patients werefollowed up for 6 months. Mortality and outcome were not significantlydifferent between the groups. Overall mortality at 4 weeks was5.2% and at 6 months was 15.1%—figures which are considerablylower than in some other comparable studies. This study doesnot support the suggestion that general anaesthesia with controlledventilation is associated with increased postoperative mortality. ^*Department of Anaesthetics, Royal Devon & Exeter (Wonford),Exeter. Acting District Medical Officer, Northampton Health Authority.     

INCREASED VENTILATION REQUIREMENTS DURING OBSTETRIC GENERAL ANAESTHESIA

The inspiratory fresh gas flow rate (FGF) required to producean end-tidal carbon dioxide tension (PE' _CO2)of 4kPa duringgeneral anaesthesia, neuromuscular blockade and artificial ventilation,was compared in a group of 46 obstetric patients and a matchedgroup of 50 non-pregnant female patients. The non-pregnant patientsrequired a mean (SD) inspiratory FGF of 77 (10.6) ml kg^–1min^–1, whereas the pregnant patients required a mean FGFof 121 (24.6) ml kg^–1 min^–1 before delivery (inthose who reached a stable state), and 109 (19.3) ml kg^–1min^–1 after delivery. These represent significant (P <0.0001) increases of 57% and 42%, respectively, over the non-pregnantstate. ^*Anaesthetics Unit, The London Hospital, Whitechapel, LondonEl IBB. 335, Southampton Road, Titchfield, Hants PO14 4AX. Northampton General Hospital, Whitechapel, London E1 1BB.     

SEDATION DURING SPINAL ANAESTHESIA: COMPARISON OF PROPOFOL AND MIDAZOLAM

Propofol and midazolam were compared in 40 patients undergoingorthopaedic surgery under spinal anaesthesia. An infusion ofeither 1% propofol or 0.1% midazolam was given at a rate adjustedto maintain a similar level of sedation. The mean time to reachthis required level was similar in both groups. Quality andease of control of sedation were good in all patients. A meaninfusion rate of 3.63 mg kg^–1 h^–1 was required forpropofol and 0.26 mg kg^–1 h^–1 for midazolam. Immediaterecovery, as judged by ability to open eyes and recall dateof birth, was significantly more rapid following propofol (P< 0.0001). Similarly, restoration of higher mental functionwas significantly faster following propofol, measured by choicereaction time and critical flicker fusion threshold. Amnesiafor the immediate postoperative period was significantly greaterafter midazolam (P = 0.0001). ^*Present address: Department of Anaesthetics, Royal Infirmary,Edinburgh. Present address: Intensive Therapy Unit, Western General Hospital,Edinburgh.     

A HAEMORHEOLOGICAL STUDY OF LIGNOCAINE

Eight volunteers received lignocaine 75 mg i.m. Peak plasmalignocaine concentrations (mean 0.80µg ml^–1; range0.31–1.86µg ml^–1 were attained at 30 min.Haematocrit and red cell deformability remained unchanged. Lignocainecaused small but significant decreases in plasma viscosity andwhole blood viscosity at both high and low shear rates (94 and0.94 s^–1). The small reductions in plasma viscosity andhigh shear blood viscosity observed ex vivo may be the resultof alterations in plasma proteins. The reductions in low shearblood viscosity are considered to result from decreased redcell aggregation.s Department of Anaesthetics, Royal Infirmary, Alexandra Infirmary,Paisley, Renfrewshire. *Department of Anaesthetics, The University of Sheffield MedicalSchool, Beech Hill Road, Sheffield S10 2RX     

PHARMACOKINETICS OF MORPHINE FOLLOWING ADMINISTRATION BY THE BUCCAL ROUTE

The pharmacokinetics of morphine administered via the buccalroute as a controlled release formulation were assessed afterthe administration of three different doses and found to belinear in the dose range 10–30 µg. The plasma concentrationsof morphine-3-glucuronide and morphine-6-glucuronide demonstratedconsiderable inter-subject variation and conclusions could notbe drawn regarding their pharmacokinetics. These large differencesmay reflect not only variability in buccal absorption, but mayhave resulted from the preparation dissolving in saliva, followedby absorption from the gastrointestinal tract. ^* Present addresses: Sir Humphry Davy Department of Anaesthetics,Bristol Royal Infirmary Bristol Present addresses: Shackleton Department of Anaesthetics, SouthamptonGeneral Hospital Southampton     

REPAIR OF TRAUMATIC TRANSECTION OF THE THORACIC AORTA: ESMOLOL FOR INTRAOPERATIVE CONTROL OF ARTERIAL PRESSURE

We report the intraoperative use of esmolol for control of arterialpressure during repair of a traumatic transection of the descendingthoracic aorta. A mean infusion rate of esmolol 50.5 µgkg^–1 min^–1 resulted in a decrease in mean arterialpressure to 63 mm Hg and heart rate to 99 beat min^–1 andwas associated with excellent surgical conditions. The infusionrate of esmolol was titrated easily against mean arterial pressure,which increased rapidly on discontinuing its infusion. Controlof arterial pressure with esmolol was comparable to that achievedwith sodium nitroprusside, but without the reflex tachycardiaor decrease in ?aOl associated with the latter agent. ^*Present addresses: Department of Anaesthesia, St Helier Hospital,Wrythe Lane, Carshalton, Surrey SM5 1AA. Department of Anaesthetics, Charing Cross Hospital, Fulham PalaceRoad, London W6 8RF.     

COMPARISON OF THE EFFECTS OF ORG NC45 AND PANCURONIUM BROMIDE ON HEART RATE AND ARTERIAL PRESSURE IN ANAESTHETIZED MAN

The effects of Org NC 45 and pancuronium bromide on heart rateand arterial pressure were studied in anaesthetized man A bolusof either Org NC450.12mg kg^–1 or pancuronium 0.1 mg kg^–1was administered to lightly anaesthetized unstunulated subjects.Following Org NC 45 heart rate decreased in the majority ofsubjects (mean and SEM 3.78 ± 1.36), whereas after pancuroniumheart rate was increased (mean and SEM 11.91 ± 1 9).The changes in mean arterial pressure observed were minimalThe effect of endotracheal intubation on mean arterial pressurewas then studied. Increase of mean arterial pressure was observedin all subjects. The increase was more marked in those patientswho had received pancuronium and was significantly higher thanm those patients who had received Org NC45 (P<0.01) We concludethat Org NC 45 is devoid of vagal blocking acoon, and that thedifference m response to the stimulus of endotracheal intubationis a result of the different effects exerted on the sympatheticnervous system by Org NC 45 and pancuronium. ^*Present addresses: Department of Anaesthetics, Kingston Hospital,Kingston upon Thames, Surrey. Present addresses: Department of Anaesthetics, Royal HampshireCounty Hospital, Winchester, Hants.     

VENTILATION, VENTILATORY CARBON DIOXIDE AND HORMONAL RESPONSE DURING HALOTHANE ANAESTHESIA AND SURGERY IN CHILDREN AFTER MIDAZOLAM PREMEDICATION

In 14 intubated, spontaneously breathing children with bodyweight (bw) ranging from 8.3 to 25.6 kg, the influence of midazolam0.1 mg kg^–1 i.m. (group M_0.1', n = 7) and 0.2 mg kg^–1i.m. (group M_0.2' n = 7) as pre-medication, on sedation, ventilation,ventilatory response to carbon dioxide and hormonal stress responsewas studied in connection with minor surgical procedures duringhalothane anaesthesia. The concentrations of catecholamines,ACTH and cortisol were measured immediately after induction,during undisturbed anaesthesia, during surgery and 15 min afterthe end of the surgical procedure. Sedation was better and plasmacatecholamine concentrations during undisturbed anaesthesiawere less in children receiving the larger dose of midazolam.During surgery and in recovery there were no differences inhormone concentrations. In recovery, the concentrations of allhormones were significantly greater compared with during undisturbedanaesthesia. During surgery, VE and respiratory rate were somewhatlower in group M_0.2 while E'_CO2, was similar. A dose dependentdepression of the response to carbon dioxide was found. However,clinically, the response to carbon dioxide after surgery wasconsidered to be adequate in both groups. ^*Department of Anaesthesia, Manchester Royal Infirmary, OxfordRoad, Manchester Ml3 9WL. Department of Anaesthesia, University Hospital, S-221 85 Lund,Sweden Department of Clinical Chemistry, University Hospital, S-22185 Lund, Sweden Department of Anesthesiology, Vanderbilt University, Nashville,Tennessee 37232, U.S.A.     

BETA-ADRENOCEPTOR BLOCKADE, ALPHA-STIMULATION AND CHANGES IN PLASMA POTASSIUM CONCENTRATION AFTER SUXAMETHONIUM ADMINISTRATION IN DOGS

A study involving 20 mongrel dogs tested the hypotheses thatbeta-adrenoceptor blockade or alpha-adrenoceptor stimulationmay potentiate and prolong the increase in plasma potassiumconcentration after suxamethonium administration, and that thebeta effect is beta₂-receptor mediated. Propranolol 0. 5 mgkg^–1 altered the time to peak increase in plasma concentrationof potassium after suxamethonium, but did not increase peakconcentrations. In controls, the maximum change (0. 83 mmollitre^–1) occurred at 3 min, while in propranolol-treateddogs the peak change (0. 96 mmol litre^–1 occurred at 30min. Similar results were obtained when metoprolol 0. 25 mgkg^–1 and ICI 118551 0. 1 mg kg^–1 were used, respectively,as selective betax- and beta₂-adrenoceptor blockers. The increasesin potassium concentration following suxamethonium in the metoprololgroup (0. 98 mmol litre^–1) and the ICI 118551 group (0.82 mmol litre^–1) reached maximum concentrations at 30min compared with the controls (0. 79 mmol litre^–1) whichachieved a maximum at 3 min. Phenylephrine was infused at 8fig kg^–1 min^–1 to produce alpha stimulation. Theinfusion alone altered plasma concentrations of potassium, butthe haemodynamic changes were such that conclusions as to theeffect of alpha-stimulation on release of potassium after suxamethoniumcould not be reached. ^*Present address: Department of Anaesthesia, The London Hospital,London El IBB. Presented in part at the Annual Scientific Meeting of the Associationof Anaesthetists of Great Britain and Ireland, September 1985and at the 60th Congress of the International Anesthesia ResearchSociety, Las Vegas, march 1986.     

Propofol infusion and the suppression of consciousness: dose requirements to induce loss of consciousness and to suppress response to noxious and non-noxious stimuli

We have defined the infusion dose requirements of propofol tosuppress consciousness and response to a variety of graded non-noxiousand noxious stimuli in 52 unpremedicated patients aged 16–40 yr and 32 patients aged 41–65 yr. They were allocatedto receive one of five loading dose-infusion schemes designedto establish stable conditions covering the range from wakefulness,through sedation, to loss of consciousness and anaesthesia.At 10 and 20 min after the loading dose, each patient's responseto a graded series of stimuli was recorded. Probit analysiswas used to derive mean values (95% confidence interval) forthe ED₅₀ and ED₉₅ (as final infusion rate) for loss of responseto verbal command at 4.9 (4.7–5.1) mg kg^–1 h^–1and 7.9 (7.3–8.8) mg kg^–1 h^–1, respectively,in the young group and 4.2 (4.0–4.4) mg kg^–1 h^–1and 5.8 (5.4–6.4) mg kg^–1 h^–1 respectively,in the older group. In both groups the dose-response curvesfor suppression of proprio-ception, finger counting and perceptionof light touch in conscious patients were shifted to the leftof the curves for loss of consciousness and eyelash reflex.Dose-response curves for noxious stimuli were shifted to theright of those for loss of consciousness. (Br. J. Anaesth. 1994;72: 29–34) Presented in part to the Anaesthetic Research Society, Exeter,March 1991 (British Journal of Anaesthesia 1991; 67: 214-215P). ^*Department of Anaesthesia, Frenchay Hospital, Bristol      

SYNERGISTIC INTERACTION BETWEEN MIDAZOLAM AND PROPOFOL

We gave either midazolam or propofol for induction of anaesthesiato 140 ASA I or II female patients (18–60 yr). ED₅₀, valueswere obtained by probit analysis for three clinical end-points:loss of response to command; loss of eyelash reflex; failureto respond to application of an anaesthetic face mask delivering1 % isoflurane. Propofol ED₅₀ values (95% confidence intervals)were 1.25 (0.99–1.48) mgkg^–1, 1.61 (1.29–1.94)mg kg^–1 and1.51 (1.20–1.82) mg kg^–1, respectively.ED₅₀ values for midazolam were 0.26 (0.20–0.37) mg kg^–1,0.29 (0.23–0.47) mgkg^–1 and 0.25 (0.20–0.32)mg kg^–1, respectively. An additional 92 similar patientsreceived one of nine dose combinations of midazolam and propofolfor induction of anaesthesia, propofol being administered 2min after midazolam. Success of induction was based on the clinicalend-point of loss of response to command. Administration of25% of the ED₅₀ of midazolam followed by 50% of the ED₅₀ ofpropofol resulted in loss of response to command in 50 % ofpatients, while 50 % of the ED₅₀ of midazolam, followed by 25%of the ED₅₀ of propofol had the same effect. A probit regressionmodel specifying a synergistic interaction between midazolamand propofol fitted the data significantly better than a modelspecifying no interaction. ^*Present address, for correspondence: Department of Anaesthetics,Royal Group of Hospitals, Grosvcnor Road, Belfast BT12 6BA,N. Ireland     

THE EFFECT OF HALOTHANE AND THIOPENTONE ON VENTILATORY RESPONSES MEDIATED BY THE PERIPHERAL CHEMORECEPTORS IN MAN

The activity and responsiveness of the peripheral ventilatorychemoreflex were assessed by the transient depression of ventilationfollowing two breaths of oxygen in air-breathing subjects, andthe differing times of onset of the ventilatory response toi.v. sodium bicarbonate in subjects breathing either air oroxygen. In patients premedicated with pethidine, in whom anaesthesiawas induced with thiopentone, it was found that halothane, inan inspired concentration of 0.7–0.8%, reduced the activityand responsiveness of the peripheral ventilatory chemoreflexmarkedly. When halothane was discontinued and anaesthesia wasmaintained with intermittent injections of thiopentone (0.2mg/kg/min) evidence of peripheral chemoreceptor activity andresponsiveness returned. ^*Departments of Anaesthesia and Physiology, University of Toronto,Toronto, Ontario, Canada. Department of Anaesthetics, Harefield Hospital, Harefield, Middlesex.     

DELAYED EXCITATORY REACTION FOLLOWING INTERACTION OF COCAINE AND MONOAMINE OXIDASE INHIBITOR (PHENELZINE)

A case report is presented in which a patient receiving themonoamine oxidase inhibitor, phenelzine, developed a delayedexcitatory reaction following administration of topical cocainespray during anaesthesia for vocal cordsurgery. The pharmacologicalbasis of the drug interaction is discussed. ^*Department of Anaesthesia, St Bartholomew's Hospital, WestSmithfield, London EC1A 7BE. Shackleton Department of Anaesthetics, Southampton General Hospital,Tremona Road, Southampton S09 4XY. Harefield Hospital, Uxbridge, Middx UB9 6JH.     

FOLINIC ACID PROTECTION AGAINST NITROUS OXIDE TERATOGENICITY IN THE RAT

The Sprague-Dawleyrat was used to demonstrate the effect ofnitrous oxide, with and without folinic pretreatment, on reproductiveindices and fetal development. One of the objectives of theinvestigation was to test the hypothesis that at least someof the teratogenic effect of nitrous oxide is related to interferencewith folate metabolism. Groups of animals were exposed to 70–75%nitrous oxide on day 9 of pregnancy with or without folinicacid 0. 1 mg i. p. 12 h before, and immediately before, exposure.Subsequent fetal development was compared with that of variouscontrol groups. There were no significant differences in fetalsurvival, but fetal weights were reduced in both groups exposedto nitrous oxide. Of the indices of skeletal maturity, the numberof ossified sternebrae was reduced only in the nitrous oxidegroup not receiving folinic acid. The incidence of major skeletalabnormalities in the untreated nitrous oxide group was significantlyincreased to five times that of the control groups, whereasthe incidence in the nitrous oxide group receiving folinic acidwas not significantly different from control. It is concludedthat pretreatment with folinic acid can at least partially reducethe teratogenic effects of nitrous oxide in the rat. ^*Department of Anaesthetics, Middlesex Hospital, Mortimer Street,London Wl Department of Anaesthetics, Wnetworth Hospital, Durban, SouthAfrica     

VENTILATION AND GAS EXCHANGE DURING ANAESTHESIA AND SURGERY IN SPONTANEOUSLY BREATHING INFANTS AND CHILDREN

Minute ventilation (VE) (mlmin^–1), respiratory frequency(f), mixed expired carbon dioxide fraction (FCO₂ and end-tidalcarbon dioxide concentration E'CO₂) (%) were measured, and alveolarventilation (VA), deadspace (VD), deadspace/tidal volume ratio(VD/VT) and carbon dioxide output (VCO₂) calculated in 58 anaesthetized,spontaneously breathing infants and children weighing 2.8–20.5kg.Although minute volumes varied, tidal volume correlated wellwith weight (r = 0.83), with a mean tidal volume (± ISD)of 5.2±1.2mlkg^–1. It was concluded that, by theuse of mean VT + ISD (approximated to 6 ml kg^–1) the freshgas flow in mlmin^–1 should be set at 2.5x6xkgxf(15xkgxf)to avoid rebreathing in various T-piece systems in anaesthetized,intubated and spontaneously breathing infants up to a body weightof 20 kg. End-tidal carbon dioxide concentration was lower inyounger patients who were premedicated with atropine alone thanin the older ones who received opioid premedication also. Respiratoryfrequency, VD/VT and total VD per minute were higher in theyounger age group, which explained the finding of a high VEin relation to VCO₂ for these patients. This inefficiency ofventilation emphasizes the need to minimize apparatus deadspacein breathing systems used for small infants. ^*Department of Anaesthesia, University Hospital, S-22185 Lund,Sweden. Department of Anaesthesia, St George's Hospital, Blackshaw Road,London SW17.     

CARDIORESPIRATORY RESPONSES TO AN I.V. INFUSION OF DOBUTAMINE IN THE INTACT ANAESTHETIZED DOG

The cardiorespiratory responses to an I.V. infusion of dobutaminehydrochloride were assessed in eight anaesthetized, mechanicallyventilated dogs As the rate of infusion of dobutamine was increasedfrom 2 to 30 µg kg^–1min^–1, there was a progressivedecrease in arterial pressure, pulmonary wedge pressure andarterial pH. There was a significant decrease in arterial oxygentension at the greater doses of dobutamine (15 and 30 µgkg^–1min^–1) from initial control values. Carbon dioxide output,arterial carbon dioxide tension, venous admixture and oxygenconsumption increased during the infusion of dobutamine. However,oxygen supply increased further so that the oxygen consumption:supply ratio decreased It is concluded that dobutamine may decreasearterial oxygen tension, but that the increased cardiac outputand decreased arterial pH produced by dobutamine may increaseoxygen supply to the tissues in spite of this. ^*Present addresses: Department of Physiology, University CollegeLondon, Gower Street, London WC1E 6BT. Present addresses: Nuffield Department of Anaesthetics, RadcliffeInfirmary, Oxford 0X2 6HE.     

Onset and duration of mivacurium-induced neuromuscular block in patients with Duchenne muscular dystrophy

Background. To determine the response to mivacurium, we prospectivelystudied onset time and complete spontaneous recovery from mivacurium-inducedneuromuscular block in patients with Duchenne muscular dystrophy(DMD). Methods. Twelve boys with DMD, age 5–14 yr, seven of themwheelchair-bound, ASA II–III, and 12 age- and sex-matchedcontrols (ASA I) were enrolled in the study. Anaesthesia wasinduced with fentanyl 2–3 µg kg^–1 and propofol3–4 mg kg^–1 titrated to effect, and maintained bycontinuous i.v. infusion of propofol 8–12 mg kg^–1and remifentanil as required. The lungs were ventilated withoxygen in air. Neuromuscular transmission was assessed by acceleromyographyusing train-of-four (TOF) stimulation every 15 s. After baselinereadings, a single dose of mivacurium 0.2 mg kg^–1 wasgiven. The following variables were recorded: (i) lag time;(ii) onset time; (iii) peak effect; (iv) recovery of first twitchfrom the TOF response to 10, 25 and 90% (T₁₀, T₂₅, T₉₀) relativeto baseline; (v) recovery index (time between 25 and 75% recoveryof first twitch); and (vi) recovery time (time between 25% recoveryof first twitch and recovery of TOF ratio to 90%). For comparisonbetween the groups the Mann–Whitney U-test was applied. Results. There were no differences between the groups in lagtime, onset time and peak effect. However, all recorded recoveryindices were significantly (P<0.05) prolonged in the DMDgroup. The median (range) for time points T₁₀, T₂₅ and T₉₀ inthe DMD and control group was 12.0 (8–16) vs 8.4 (5–15)min, 14.1 (9–20) vs 10.5 (7–17) min and 26.9 (15–40)vs 15.9 (12–23) min, respectively. The recovery indexand recovery time were similarly prolonged in the DMD group. Conclusions. These results support the assumption that mivacurium-inducedneuromuscular block is prolonged in patients with DMD. This study was presented at the Annual Meeting of the AmericanSociety of Anaesthesiologists, Las Vegas, October 2004. These authors contributed equally to this work.     

TOTAL I.V. ANAESTHESIA WITH PROPOFOL AND ALFENTANIL: DOSE REQUIREMENTS FOR PROPOFOL AND THE EFFECT OF PREMEDICATION WITH CLONIDINE

We determined in 51 healthy patients undergoing body surfacesurgery the dose requirements for propofol, as part of a totali.v. anaesthesia technique with an alfentanil infusion. Afterpremedication with temazepam, patients received alfentanil 50µg kg^–1 followed by an infusion of 50 µg kg^–1h^–1. Patients were anaesthetized with a loading dose ofpropofol followed by a three-stage infusion designed to reachone of five preselected blood concentrations of propofol. Themotor response to the initial surgical incision was noted andprobit analysis was used to derive the ED₅₀ (2.94 mg kg^–1h^–1; 95% confidence limits: 2.35–3.37 mg kg^–1h^–1). and ED₉₅ (4.98 mg kg^–1 h^–1; 95% limits:4.13–8.8 mg kg^–1 h^–1) for the final propololinfusion rate under these conditions. Whole blood concentrationof propofol at the time of the incision was related linearlyto the infusion rate and the EC₅₀ and EC₉₅ (probit analysis)were derived as 1.44 (95% confidence limits 0.62–1.87)and 4.05 (95% confidence limits 2.78–30.5) µg ml^–1,respectively. Postoperative recovery was rapid, uncomplicatedand uneventful. In a subgroup of eight patients, the additionof clonidine 0.6mg to the premedication significantly decreasedthe requirement for propofol (P <0.05) during surgery, butresulted in prolonged recovery times. Pilot study presented to the Anaesthetic Research Society, June24, 1988 [1].     

COMPARATIVE STUDY OF LORAZEPAM AND TRIMEPRAZINE FOR ORAL PREMEDICATION IN PAEDIATRIC ANAESTHESIA

One hundred and ninety-nine children received either lorazepam0.05 mg kg^–1 or trimeprazine 3 mg kg^–1 as oral premedicationin a double-blind trial. Lorazepam proved more palatable andproduced a cheerful demeanour, but possessed no significantadvantages on overall assessment before surgery Following operation,restlessness with vomiting, and evidence of retrograde amnesiaoccurred more frequently with lorazepam. ^*Present addresses: Department of Anaesthesia, New Cross Hospital,Wol-verhampton, West Midlands. Present addresses: Department of Anaesthesia, Victoria Hospital,Kirkcaldy, Fife, Scotland.