Postgrad Med J: first published as 10.1136/pgmj.25.283.193 on 1 May 1949. Downloaded from '93 Annotation tissue pouting into the bronchial lumen as a result of ulceration of tuberculous hilar glands and perhaps associated with a bronchial stricture may SURGICAL TREATMENT give rise to difficulty. The diagnosis in these cases is readily established by bronchoscopy. OF ASTHMA Severe degrees of emphysema. and bullous cysts of the lung present greater difficulty. The purpose ofthis communication is to attempt Emphysema of greater or less extent is indeed a to analyse as simply as possible the present position common result of asthma and may develop at an of surgical procedures in relation to asthma. The early date, but it may also occur without true approach to the subject must necessarily be asthma and operation will afford no relief. As to guarded for there is as yet insufficient evidence giant bullous cysts, they are, in the majority of on which to base firm opinions. Medical feeling instances, unilateral and although they may appear has so far been biased against surgery because to occupy the whole of one side of the chest, they surgeons are still unable to state what are the usually arise from only one lobe and the rest of the criteria for operation and, if surgery is agreed upon, compressed lung tissue is visible. what operation is. to be done. How shall we tell which asthmatic will respond favourably and Physiological Considerations (Miscall, which will not? Gay and Rienhoff's (1938) method 1943) of choosing only cases which had failed to respond In normal respiration, active inspiration and to any other treatment and who were consequently passive expiration suffice. In asthma, the in- 'bad risks,' does not appear to be ideal for in such trinsic widespread obstruction to the conducting' ,cases thoracotomy becomes a dangerous pro- cedure, secondary changes having already Ih occurred. It would seem reasonable therefore to review certain physiological and pathological facts, re- by copyright. membering that the term ' asthma' may include 4 - more than one disease, that it may be complicated by emphysema, right heart failure and so on, and -.ir g.. that a number of other diseases by producing -7.--7 respiratory difficulty may closely simulate asth- matic attacks. Conditions Simulating Asthma Any obstruction of the major air passages, any http://pmj.bmj.com/ obstruction of a major proportion of the bronchioles as by the oedema of congestive right heart failure, or any lesion where considerable quantities of air are retained in the lung as in gross emphysema or bullous cysts of the lung, may simulate asthma. A careful clinical examination 6WI must include X-ray examination of the chest, on September 26, 2021 by guest. Protected assessment of the condition of the heart and, Above all, bronchoscopy. The commonest types of obstruction of the major air passages producing expiratory difficulty are those which have a valvular action. In the larynx, for instance, a papilloma hanging from a vocal cord may be nipped in the glottis in expira- tion (Fig. I). In the same way tumours of the trachea, more especially adenomata of peduncu- lated type may not seriously impede inspiration but may cause the greatest difficulty in getting rid of the inspired, air (Fig. 2). Such stifferers may show an X-ray picture of the lungs indistinguish- able from those of the asthmatic. Again, similar tumours of the major bronchi or even granulation FIG. I.-Valvular tumour of vocal cord Postgrad Med J: first published as 10.1136/pgmj.25.283.193 on 1 May 1949. Downloaded from 194 POST GRADUATE MIEDICAL JOURNAL MaIVY 1949 function but it is extremely complex in that it is affected by both sympathetic and parasympathetic afferent impulses on the one hand and by chemical influences in the shape of carbondioxide, anoxia and various toxic substances on the othcr. Both the sympathetic and parasympathetic divisions of the autonomic nervous system affect respiration in as much as they each contain afferent and efferent fibres from and to the lung. From the pulmonary stretch receptors, stimu- lated by expansion, impulses pass up the vagi chiefly from the homolateral lung and inhibit the inspiratory centre. Trhe ganglia of these fibres are found in the ganglion nodosum. The afferent //Ii fibres pass via the upper five thoracic sympathetic ganglia and probably also over the cardiac ac- celerator nerves. Stimulation of them causes broncho-constriction via the vagal efferents. 'rhe vagal efferents whose fibres originate in the dorsal vagal nuclei are, like the vagal afferents, almost entirely homolateral in their lung dis- tribution and in function are broncho-motor and f:: \\ I secretory. Division of them thus results in secretory inhibition and broncho-dilatation. 'The sympathetic efferents however reach the lung either directly from the upper dorsal ganglia or over the accelerator nerves, being chiefly v-aso-by copyright. motor and broncho-dilator in function. 'iG(;. 2.-Va!vular tumour of trachea. Surgical Considerations Where intractable asthma exists, thereforc, and airway s-stem causes a demand in excess of the where there are no contra-indications to the opera- ability to ventilate. Laboured breathing results. tion, it would seem rational to interrupt the -agal 'This obstruction is of two kinds, namely spasm distribution to the lungs on both sides. So far as of the bronchial muscles can be judged, no unpleasant sequelae follows due to overstimulation http://pmj.bmj.com/ and secondly, the presence of excessive tenacious posterior-pulmonary plexus resection for this mucus. 'T'he muscle spasm affects principally the purpose other than the risks involved in opera- terminal bronchioles because these, unlike the tions upon subjects whose respiratory and con- bronchi, are unsupported by cartilage whilst the sequent cardiac capacity is impaired. By, so doing, mucus affects chiefly the small bronchi, since the the relief of excessive tonus of the broncho- bronchioles are not lined by mucus-secreting constrictor muscles and the diminution of secre- glands. tion no longer traps air in the distended alveoli and It is thought that attacks may be precipitated by residual air therefore falls. Blood passing through on September 26, 2021 by guest. Protected a variety of stimuli ranging from lesions in the the lungs is more freely aerated and the pulmonary nose and throat to direct stimuli arising in the resistance reduced, thus relieving right heart strain. lung from the effects of substances of an allergic In all probability, even if a moderate amount of nature. It may be that these are allied to or are of emphysema is present as a result of alveolar septal similar nature to histamine. W hether in some rupture, considerable relief may be obtained. cases these act directly upon the bronchial The differentiation of clinical types of asthma is musculature Nithout the intervention of a reflex important. Where real allergy exists and the arc is as yet uncertain but the evidence is that in bronchial muscles are sensitive, surgery may well the majority of instances overstimulation of the be both unnecessary and contra-indicated, but in bronchial muscles and glands (loes require a reflex the larger group where no distinct allergy is arc, the pathw-ays of which are now knowNn. In demonstrable various infective sources may be the allergic state, this arc may be hypersensitive to responsible for the abnormal bronchial spasm. stimuli w-hich in the normal person would be in- 'These may be either pulmonary or extra- sufficient to cause an effect or response. pulmonary (e.g. nasal); or again the main cause 'IThe respiratory centre integrates all respiratory may be psychological. Postgrad Med J: first published as 10.1136/pgmj.25.283.193 on 1 May 1949. Downloaded from May 1949 BARLOW: Surgical Treatment of Asthma 195 the operated side. This can be kept partially in- flated and the operation can be stopped as often as desired in order to re-inflate it completely for a few minutes. The best approach is through an ordinary lateral thoracotomy, using the sixth intercostal space or resection of the sixth rib. The lung is gently held forward, the pleura opened across the back of the pulmonary hilum and the vagus identified. On the right side (Fig. 3) it is necessary 1-- to ligate and divide the azygos vein whilst on the left (Fig. 4) very special care is required to pre- :ElVa8<s-Xt serve the recurrent laryngeal nerve which turns :\:::|EB upwards close under the aortic arch. Pulmonary * %;f.:.::.,.:: t\.:. -..' vagal branches leave the main trunk not :.1:w\VZ= only *..w.,.'..=.'..'.S...S <.,e..i..j;x m l Z.,....lS.' \ { opposite the hilum but both above and below this x:s% *: \ ... ---..- ...>..0... .-...v. 'l -. level and it is of course essential to identify and .. i\. w; .... .; ,,Lj-x,, divide them all. This takes a little careful dis- ..".: '.;': ,....,.X"", section but the whole operation is straight- ...:; :; .:,:....,' ,.: s. '-w-.'. w....-.'t....t,:',.,-,,.;;>.;:-::'\.3. forward. Having divided the fibres either simply *.::.:\\;:.................:-::..':.'.:,.........,'.:. or between ligatures (the question of regeneration FIG. 3.-fosterior pulmonary plexus, right side. is still uncertain) the pleura is closed by a con- tinuous suture and after re-expanding the lung fully, the chest is closed. Provided..........that., sources of infection and of psycho- .... not only care be . As has stated, should ..--.->*.............-... been logical stimulation have been dealt with and that taken not to divide the recurrent laryngeal nerve the patient is not in severe heart failure, cases may on the left side but it should not be stretched. by copyright. be considered for bilateral posterior pulmonary Even slight stretching will cause a temporary vocal plexus resection, an interval of two or more weeks cord paralysis which is distressing to the patient elapsing between operations on each side.