Pulmonary complications of general surgery

Postoperative intensive care admittance: the role of tobacco smoking

BACKGROUND

Smokers have been shown to have increased risk of intraoperative pulmonary complications and of a wide range of postoperative complications, but an increased risk of postoperative intensive care admittance has not yet been described. The aim of this study was to estimate the risk of pulmonary complications and postoperative intensive care admittance in smokers and non-smokers in a general and orthopaedic surgical population.

METHODS

A total of 4725 surgical patients were assessed. The following information was noted: age, sex and smoking status, history of heart and lung disease, ASA classification, type of anaesthesia, intensive care admittance and postoperative pulmonary or cardiovascular complications. A logistic regression model was used to determine the probability of intensive care admittance and pulmonary complications as a function of smoking status, age, and chronic heart and lung disease.

RESULTS

Of the patients, 39.9% were smokers, 45.5% were non-smokers and in 14.6% of the cases smoking status was unspecified. Postoperative intensive care admittance and pulmonary complications were found in 2.0% and 4.3% of the patients, respectively. Non-smokers were more often female (P<0.01), and smokers had a higher incidence of emergency surgical procedures (P<0.05). When applying multiple regression analysis, we found that smoking, age >65 years, and a history of chronic lung disease increased the risk of unplanned intensive care admittance (odds ratio 1.55, 12.52 and 2.73).

CONCLUSION

Our results indicate a relationship between a history of tobacco smoking and postoperative intensive care admittance.

Nosocomial pneumonia in the medical and surgical patient. Risk factors and primary management

Nosocomial pneumonia is a large and growing problem in American hospitals. This article reviews the epidemiology, risk factors, microbiology, natural history, and presentation of nosocomial pneumonia. Pathogenesis is also reviewed, and practical measures for prevention are stressed.

Anaesthetic considerations for microsurgical repair of limbs

With the advent of surgery under the operating microscope microvascular surgical techniques requiring prolonged anaesthesia have greatly increased in number. Local anaesthetic techniques, whilst often producing excellent surgical conditions, are limited by the duration of action of the anaesthetic agents and by the ability of the patient to remain still, often in uncomfortable positions, for periods of up to twenty hours. The use of indwelling catheters as a means of prolonging the duration of nerve blocks is discussed along with methods of sedation or general anaesthesia to enable the patient to tolerate lengthy surgical intervention. Present general anaesthetic techniques may not be ideally suited to long surgical procedures. The problems and possible alternatives are discussed. Sympathetic ganglion blockade, intravenous regional blockade and systemic vasodilator therapy are discussed as a means of improving the success rate of these procedures. The general principles of patient management such as fluid balance, temperature control, patient positioning and control of the operating room environment assume a much greater significance when related to the provision of prolonged general anaesthesia, whilst the effect of extended periods of work on operating personnel must also be considered.

The role of the routine pre-operative chest X-ray in the elderly general surgical patient

In an unselected group of 233 patients aged 65 years and over undergoing non-cardiopulmonary surgery, 57·5% had some abnormality on routine pre-operative chest X-ray and 40·3% had an abnormality which was regarded as clinically significant. Of all patients, 32·2% subsequently required a postoperative chest film for diagnostic purposes, and in these cases the pre-operative X-ray was invaluable as a baseline. During the study period there were ten occasions where the discovery of an abnormality on a routine pre-operative chest film directly affected the treatment plan. Pre-operative chest radiology proved ineffective as a method of predicting postoperative respiratory complications and was of only limited effectiveness in predicting postoperative cardiac morbidity.

It is concluded that a routine pre-operative chest X-ray should be available in all elderly surgical patients (a) as a baseline measurement and (b) to exclude unsuspected disease. The prediction of postoperative cardiac and respiratory morbidity, however, is best achieved by non-radiological means.

Postoperative respiratory morbidity: identification and risk factors

Two hundred consecutive patients admitted for general surgery were studied prospectively to evaluate the contribution of risk factors to postoperative respiratory morbidity (PORM). PORM was expressed both in terms of individual clinical features present on the second postoperative day (when the incidence was greatest), and as an aggregate score incorporating many clinical features. The importance of recognised risk factors, such as previous respiratory disease, cigarette smoking, upper abdominal procedures and the duration of surgery was confirmed, in that these factors were associated with some of the individual clinical features of PORM. The relative importance and independent contribution of these risk factors were assessed by their association with the aggregate score. A naso-gastric tube (NGT) present for 24 hours postoperatively was the factor more associated with PORM. The NGT identified patients at risk more clearly than, and independently of, the next most important factor, upper abdominal surgery. The duration of surgery did not contribute to PORM after the influence of NGT and site of surgery had been considered. Previous respiratory disease predisposed to PORM, and was best identified by, in order of importance, an observed productive cough, a reduced one second forced expiratory volume, and purulent sputum. After the incidence of these factors had been considered, cigarette smoking and a history of a chronic productive cough did not contribute further to PORM.

[Postoperative weaning from mechanical ventilation in adults]

Pulmonary complications remain the most frequent of postoperative complications (32-60), especially after upper abdominal surgery (14-41). Chronic respiratory insufficiency (80) also continues to be a major risk factor, in spite of the progress made in both anesthesiology and postoperative care. In the immediate postoperative period, weaning from mechanical ventilation is one of the most dangerous phases of anesthesia (84). We discuss the importance of weaning procedures, in particular, in patients with a high risk of pulmonary complications.

Pulmonary atelectasis after anaesthesia: pathophysiology and management

The pathophysiological basis of pulmonary atelectasis is reviewed and risk factors that enhance lung collapse are discussed. Management strategies to reduce or eliminate risk factors and to prevent collapse are discussed and the rational bases of these strategies are identified. Instability of lung alveoli is a consequence of surface tension and regional differences in alveolar size. The inherent tendency of alveoli to collapse is enhanced by the following risk factors; low lung volume, high closing volume, oxygen therapy, a rapid shallow ventilatory pattern, chronic lung disease, smoking, obesity, postoperative pain following abdominal or thoracic surgery, narcotic induced ventilatory depression, and neurological, neuromuscular, muscular and musculoskeletal diseases associated with mechanical impairment of respiratory function. The primary goal of perioperative respiratory management is prevention of atelectasis. Appropriate management strategies include physiotherapy and delay of elective surgery if substantial improvement in respiratory status can be achieved by specific treatments such as antibiotics, bronchodilators, steroids, and reduction of tobacco use and caloric intake. In selected cases, elective postoperative controlled ventilation may be indicated.