Condensation of α- and β-Acetylnaphthalenes with Dimethyl Diglycollate

α-and β-Acetylnaphthalenes condense with dimethyl oxydiacetate (dimethyl diglycollate) in the presence of sodium hydride to give good yields of the corresponding half-esters, the (Z)-isomers (2a) and (2b) being predominant. The structure and configuration of the half-esters were established by chemical and spectroscopic evidence.

The Rees system in infants: fresh gas flow and PaCO2

Fresh gas flow from the anaesthetic machine can be set to determine the low level of PaCO2 that is achieved during anaesthesia using Rees variation of the T-piece. It does not however set the upper limits for PaCO2 which is more reliant upon the minute ventilation. For a PaCO2 of 40 mm Hg, it is suggested that the fresh gas flow from the machine be 220 cc/kg. For small infants, a higher flow rate is necessary.

Echocardiographic assessment of ventricular performance following induction with two anesthetics

Echocardiographic studies were made of 20 healthy patients scheduled for minor surgical procedures to determine whether this technique could be used routinely in the operating room and to evaluate the effects of halothane and enflurane on left ventricular performance. Thirteen minutes following induction of anesthesia with halothane in ten patients (mean end-tidal halothane concentration 0.93 per cent), mean arterial blood pressure, left ventricular (LV) diastolic dimension, LV fractional shortening, mean velocity of circumferential fiber shortening and systolic thickening of the posterior LV wall were significantly decreased. LV systolic dimension was increased significantly. These data indicate that halothane caused decreased contractility in the presence of a decreased afterload. Twelve minutes following induction of anesthesia with enflurane in ten patients (mean delivered enflurane concentration 2.4 per cent), mean arterial blood pressure and LV systolic and diastolic dimensions were decreased, while heart rate was increased significantly, indicating that enflurane caused vasodilatation and may have had some depressant effect on contractility. Echocardiography is a non-invasive, safe and relatively rapid method that can be used in the perioperative period to assess cardiac function and to evaluate the effects of pharmacologic agents on the heart.

Haemodynamic responses to induced arterial hypotension in children

Cardiovascular measurements were made in 12 children in whom arterial hypotension was induced with pentolinium and halothane. Propranolol was given to five patients who exhibited tachycardia. Measurements were made at the following stages: before induction of hypotension, 5 min after the administration of pentolinium, when a "dry" opening field was obtained, at the time of maximum hypotension and when arterial pressure had returned to 90% of the control values. The decrease in arterial pressure 5 min after the administration of pentolinium was accompanied by tachycardia, but there was no significant change in cardiac index and the operative field was congested. A substantial decrease in cardiac output occurred when a "dry" field was obtained.

Control of gastric acidity by glycopyrrolate premedication in the parturient

The effect of premedication with the anticholinergic quaternary ammonium compound, glycopyrrolate (0.4 mg), on gastric juice pH was investigated in 23 parturients scheduled for elective cesarean section under general anesthesia, and the results were compared to a control group of 15 nonpremedicated obstetric patients and 25 parturients premedicated with atropine (0.6 mg). In the nonpremedicated control group, the mean gastric juice pH was 2.36 (SE +/- 0.23), 66% having a pH less than the critical level of 2.5. Premedication with atropine did not significantly increase the gastric pH, while in those premedicated with glycopyrrolate, the mean pH increased to 3.7 (+/- 0.35), and the incidence of pH less than the critical level dropped to 34%. The effect of glycopyrrolate on gastric juice pH was significantly increased when the premedication-induction time was prolonged to 60 to 120 minutes. It was concluded that glycopyrrolate premedication can be used in the parturient as an additional measure to safeguard against acid-aspiration syndrome.

Haemodynamic responses to antagonism of bocurarine block with atropine-neostigmine mixture in children

Following antagonism of tubocurarine block with a mixture of atropine 20 microgram/kg and neostigmine 50 microgram/kg in 20 children, heart rate decreased from a control value of 110.4 beat/min to 90.1 at 5 min and 89.2 at 6 min (P less than 0.02). Stroke volume index did not change during the first 5 min from a control value of 36.3 ml. beat--1.m--2 but a significant increase to 48 ml. beat--1. m--2 was observed at the 6th and 7th mins following the injection of the mixture (P less than 0.05). Cardiac index and mean arterial pressure remained unaltered throughout the period of observation. Normal sinus rhythm was maintained in all patients. It was concluded that antagonism of tubocurarine with an atropine-neostigmine mixture does not produce any important haemodynamic change in children.

Tubocurarine and the neonate

Tubocurarine, given as a single bolus, may be used safely for neuromuscular blockade in the neonate. The recommended dose is 250 mug/kg at birth, increasing to 500 mug/kg at 28 days of age. This dose should be reduced in the event of prematurity, acidosis or hypothermia, or when certain antibiotics or inhalation anaesthetic agents are present in the tissues. A single dose as described has a duration of approximately 1 h and it is only after this time that satisfactory antagonism can be obtained. The potency of pancuronium when compared with tubocurarine in the study is 6:1, from birth to 28 days.

Premedicant drugs and gastric juice pH and volume in pediatric patients

The effects of premedication on gastric juice volume and pH were evaluated in five groups of 206 pediatric patients undergoing elective surgical procedures: Group 1 (Control) received no premedication; Group 2 was given morphine sulfate and pentobarbital as premedicants. The other groups received, in addition to morphine and pentobarbital, atropine (Group 3), scopolamine (Group 4), or glycopyrrolate (Group 5). After endotracheal intubation, gastric aspirates were examined for volume, pH and color. Neither premedication with morphine and pentobarbital nor addition of atropine or scopolamine to the premedication significantly altered volume. In patients treated with glycopyrrolate, volume was reduced to less than a third of that of patients in Group 1 (P less than 0.001), and the percentage of pH's higher than 2.5 was significantly greater than in other groups. The incidences of unobtainable samples and samples with pH's higher than 2.5 were greatest with atropine (32.0 per cent, P less than 0.05) and glycopyrrolate (58.1 per cent, P less than 0.01). In 60 per cent of the bile-stained specimens, pH's were below 2.5. It is concluded that because of its selective inhibitory effect on gastric acid secretions, glycopyrrolate appears superior to other anticholinergic drugs. The reduction of gastric juice volume and acidity produced by glycopyrrolate would have important clinical implications in case of accidental aspiration. It is also concluded that bile staining of gastric contents is not a reliable indicator of gastric juice pH.

Stobbe-type condensation involving diethyl diglycollate

Benzaldehyde, p-anisaldehyde, acetophenone and acetone condense with diethyl diglycollate in the presence of sodium hydride to give fairly good yields of the corresponding half-esters. With benzaldehydeand p-anisaldehyde the (Z)-half-esters (2a) and (2b) predominated. Condensation with benzophenone was only effected with potassium t-butoxide in boiling t-butyl alcohol. The structure and configuration of the half-esters was established by chemical and spectroscopic evidence.

Cardiac arrest related to anesthesia. Contributing factors in infants and children

A collaborative retrospective study undertaken to investigate cardiac arrest related to pediatric anesthesia in seven institutions between 1960 and 1972 showed 73 instances in which anesthesia was thought to have been either directly responsible or had played an important contributing role. About two thirds of these patients were successfully resuscitated. Cases were found to fit into one of two major categories: cardiovascular and respiratory. Among cardiovascular factors, blood loss, preoperative anemia, inappropriate administration of succinylcholine, and accidental administration of potassium were important contributing causes. Respiratory factors included failure to maintain a patent airway and ventilatory problems. In retrospect, most of these accidents were preventable. Such information should indicate where research emphasis needs to be placed and that our current methods of teaching and training need to be reevaluated.

Pancuronium and the neonate

Pancuronium bromide was used safely as the muscle relaxant for neonatal anaesthesia. No untoward effects were seen and the neuromuscular block was successfully reversed in all patients. The potency ratio of pancuronium as compared with tubocurarine ranged from 9:1 at birth to 6:1 at one month of age.