No abstract

Direct measurements of arterial blood pressure and intracranial pressure were recorded in 39 patients aged 3-6 months to 5 years 11 months with Reye's syndrome judged to be stage 2 or beyond. Of 33 patients who survived, 27 made a full recovery and six were

The ability of premedicant drugs to suppress memory of events immediately prior to the induction of anaesthesia, without causing marked depression of consciousness or other vital functions, would appear to be very desirable. This is shown by the many recent publications on the subject of amnesial-4. In one of these, Pandit & Dundee studied over 2,600 patients undergoing minor gynaecological surgery under a standard (methohexitone -nitrous oxide -oxygen) anaesthetic and found a very small incidence of amnesia from commonly used premedicants given by the intramuscular route. Only hyoscine and mixtures of opiates with either diazepam or hyoscine showed any notable effect which could be exploited clinically. Since the therapeutic and other effects of premedicant drugs are more marked when the intravenous route of administration is used, it was felt that this study should be repeated in part, using this route of administration.This paper reports a detailed study of the incidence of retrograde and anterograde amnesia and of some other effects of 15 premedicants given intravenously 15-30 minutes prior to induction of anaesthesia. One of these was saline which was used to test the validity of the method of study and also to see how frequently post-operative amnesia was due to the residual effects of anaesthesia. Active drugs chosen were either commonly used in anaesthetic practice or combinations containing diazepam or hyoscine. METHODThe study was carried out on 370 adult female patients undergoing elective minor gynaecological surgery in one unit where the operating room is adjacent to and on the same floor as the ward. Each premedicant drug was studied in groups of either 20 or 30 patients which were broadly comparable with respect to average age and weight.Prior to administration of the premedicant (which was normally given over 3-5 minutes) patients were shown five different coloured blocks and

Changes in oxygen saturation (Sao2) were studied during induction of anaesthesia in 48 healthy children receiving halothane or isoflurane for outpatient dental extractions. Substantial reductions in S k 2 occurred in more than 50% of the children given isoflurane and were associated with the irritant effects of this agent on the airway. S+,> was largely unaltered during the use of halothane. These findings indicate that the airway complications caused by isoflurane may be associated with decreases in Sac,?.Zamel D, Revow M, England SJ: Expiratory airflow patterns and gas exchange in the newborn infant: Results of model simulations. Respir Phwiol 1989; 75:19-28.A mathematical model simulating the newborn human infant's respiratory system was used to study the effects on gas exchange of varying expiratory airflow pattern and end expiratory lung volume (FRC). Inspiratory flow was modelled as a square wave and was constant for all simulations as were inspiratory and expiratory times. Expiratory airflow was also modelled as a square wave and was varied between 21 and 75 mlisec with FRC held constant at either 30.2 or 21.2 ml/kg for each simulation. At a given FRC, expiratory airflow pattern had only a trivial effect on blood gases in the steady state. Comparing the extreme cases. fast expiration (75 mlisec) at low FRC (21. I mlikg) with slow expiration (2 I mlisec) at high FRC (30.2 mlikg). arterial Po2 was 3.8 mm Hg higher and arterial Pco, 1 .O mm HG lower under the latter conditions. However, when short apneas were imposed, blood gases deteriorated less precipitously following the slow expiration at high FRC. We conclude that expiratory airflow retardation and the resultant elevation in end expiratory lung volume do not greatly enhance gas exchange in the healthy full term infant. However, mechanisms which slow expiratory airflow do provide a buffer for gas exchange during the short apneas often observed in infants.Peslin R, Marchal P, Gallina C, Oswald M, Crance JP: Assessment of thoracic gas volume by low-frequency ambient pressure changes in children. Eur Respir J 1988; 1:594-599. Selected Reviews Schuster DP. Srate qf the art: Positron emission tomography: Theory and its application to the study of lung disease. Am Rev Respir Dis 1989; 139: 8 18 -840. Chernick V, Warshaw JB, Kiley JP. NHLBI workshop summary: Developmental neurobiology of respiratory control. Am Rev Respir Dis 1989; 139: 1295-1 301.Riley RL, Nardell EA. State of'the urt: Clearing the air-the theory and application of ultraviolet air disinfection. Am Rev Respir Dis 1989; 139: 1286-1294.

Changes in oxygen saturation (SaO2) were studied during induction of anaesthesia in 48 healthy children receiving halothane or isoflurane for outpatient dental extractions. Substantial reductions in SaO2 occurred in more than 50% of the children given isoflurane and were associated with the irritant effects of this agent on the airway. SaO2 was largely unaltered during the use of halothane. These findings indicate that the airway complications caused by isoflurane may be associated with decreases in SaO2.