G. Jackson Rees

Role of Apnoea in Anaesthesia for Major Surgery

There has been widespread support for the concept which views anaesthesia as a triad (Rees and Gray, 1950), the components of which, narcosis, relaxation,and analgesia, ideally are produced by specific drugs with selective actions. It is now a generally used method of anaesthesia to induce sleep with thiopentone, to produce muscular relaxation with a relaxant drug, and to reduce the response of the patient to noxious stimuli by the use of nitrous oxide and occasionally a more potent specific analgesic drug such as pethidine. During the past six years an anaesthetic technique based on this principle has been adopted by us. Thiopentone has been used in minimal doses to produce sleep, a 50% mixture of nitrous oxide and oxygen, if necessary supplemented by pethidine (or, in the earlier years, very minimal dos.s of ether), to produce analgesia, and a paralysant drug to attain relaxation and initiate the control of respiration. As a result of the respiratory depression subsequent upon adequate doses of the relaxant agents, there has been no-hesitation in resorting to completely controlled respiration for the cases in which this technique has been employed. The experience gained during this period led to the conolusion that use of controlled respiration reduced the dose of both relaxant and thiopentone which it was necessary to administer in these cases. The examination and significance of this possibility are the subject of this paper.

Salicylate intoxication treated with intermittent positive-pressure respiration.

The returns of the Registrar-General for England and Wales (1950-2) indicate that in this country aspirin and its derivatives remain an important cause. of death from poisoning in children. During the three years 1950-2, 21 children lost their lives in this manner. In the United States of America in 1952 there were 86 deaths from this cause in children under the age of 5 years (Committee on Toxicology, American Academy of Pediatrics, 1955). Many such cases are the result of accidental ingestion of the drug. In the experience of Heymann et al. (1954), however, the danger of intoxication following therapeutic administration of the drug is much greater. Holt (1954) has shown that the dose of salicylate administered does not bear a constant relationship to the resulting blood level and, furthermore, that the blood level at which toxic symptoms appear varies greatly from patient to patient. Various therapeutic measures have been recommended for the condition, but there appears to be no previous report of the use of intermittent positive pressure respiration. This paper is presented in order to show that this procedure may have an important place in the treatment of salicylate intoxication.

Anaesthesia for the Respiratory Cripple

It is frequently held that patients with severe respiratory disability should not be subjected to anaesthesia involving the use of relaxant drugs and positive pressure ventilation since it may be found impossible to provide adequate pulmonary ventilation after the relaxant has been given, or it may prove difficult to re‐start spontaneous ventilation if the blood carbon dioxide tension has been reduced during anaesthesia. This paper describes a simple investigation into this problem based on data obtained from 12 ‘respiratory cripples.’ All had a maximum breathing capacity of less than 40 litres/min., and eight showed pre‐operative respiratory acidosis.

Surgical Treatment of Atrial Septal Defects

The treatment of atrial septal defects is essentially surgical. We describe below our experience of the. management of a group of 12 cases. This defect is relatively common. In necropsies on congenital heart cases of all age groups Maude Abbott (1936) found the defect to be the third commonest, and in McGinn and Whites series (1936) it was the commonest. Post-mortem examinations in children show a lesser incidence as death often occurs later in life, and Disenhouse et al. (1954) found it to be sixth and Keith and Forsvth (1951) thirteenth in frequency. Woods findings (1950) in 200 patients suffering from congenital heart disease showed atrial septal defects to be the second commonest defect between the ages of 5 and 61 years. The sex incidence shows a predominance of female patients (Roesler, 1934; Cosby and Griffith, 1949; Bedford et al., 1941). The morphology of the various types of defect is best understood by a consideration of the embryological development of the septum. The atrial septum is formed by the fusion and overlapping of two septa which eventually divide the single atrium into two cavities. The first, the septum primum, appears at about the fourth week in the roof of the atrium and grows downwards both ventrally and dorsally in the sagittal plane towards the region of the atrioventricular valves and the developing ventricular septum. Growth in its central portion is slower than at the periphery, so that its lower margin becomes crescentic. There is thus left a communication between the two atria which is termed the ostium primum. This foramen then gradually closes, but at the same time the upper part of the septum breaks down to form a second deficiency-the ostium secundum. To the right of the first a second septum now develops, the septum secundum, which grows downwards to overlap the lower edge of this second foramen. The free edge of the second septum forms the annulus ovalis of the fully developed heart. There remains an oblique cleft bounded above by this free edge and, below and to the left, by the lower edge of the foramen secundum through which blood passes during foetal life from the right atrium to the left. Actual fusion of the two septa occurs before the 12th week of extrauterine life in most cases. Seven types of defect may be described (Fig. 1).

The effect of dextrose/insulin infusion on the duration of respiratory activity in the anoxic rat.

Intra-cellular brain glucose varies with the blood glucose level in both newborn and adult animals (1). In the case of the newborn, the brain/blood glucose ratio is much higher than that of the adult, as is also the brain glycogen level in the newborn. This difference in tissue carbohydrate level in the neonate is not confined to the brain, and is true of many other tissues. The period of time for which the neonatal heart will continue to beat in the face of anoxia is directly related to the myocardial glycogen content, and if this is reduced the tolerance to anoxia is reduced proportionally (2). If, in this respect, the brain is analogous to the heart, the high tolerance of the newborn brain to anoxia would be related to the brain carbohydrate level, and if the relationship between carbohydrate level and tolerance of hypoxia were causal, it should be possible to increase the tolerance of the adult brain to anoxia by increasing the carbohydrate content of the brain.