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Since 1981 long-term oxygen therapy (LTOT) has become an important procedure for the rehabilitation of patients with chronic respiratory insufficiency in Switzerland too. As a result of long-term clinical experience as well as technical progress, there is, however, increasing need for an updated reassessment of guidelines and standardized management respectively: the indications for LTOT-so far restricted to patients with COPD-are extended to patients with pulmonary diseases other than COPD associated with chronic hypoxemia (pO2 < 7.3 kPa) provided there is enough evidence of clinical benefit. Another important aspect of LTOT focuses on the appropriate application of different oxygen sources. Oxygen concentrators are still accepted to be the most economic domiciliary source. For short-term outdoor activities, small portable cylinders in combination with an oxygen conserving system should be used. However, in regular mobile oxygen therapy liquid oxygen is the best choice, generally consisting of a domiciliary reservoir and portable canisters. Delivery of oxygen through a transtracheal catheter is superior to nasal cannula because of lower oxygen consumption, decreased breathing work and improved compliance respectively. To organize and follow-up LTOT in Switzerland, a very efficient concept was introduced many years ago which is characterized by economical cooperation between physicians, insurances, technical suppliers and social providers. Today more than 3000 patients-corresponding to 38/100,000 inhabitants-benefit from LTOT. Future perspectives should target an earlier start to continuous as well as mobile LTOT, in order to improve rehabilitation in still active conditions instead of merely palliating the terminal stages.

Long-term health effects of moderate ambient air pollution are rarely investigated. In Switzerland, no large-scale study has addressed this issue so far. Important results of the Swiss Study on Air Pollution and Lung Disease in Adults (SAPALDIA) are presented. During the period 1991-1993, SAPALDIA investigated a random population sample (18-60 years) in eight Swiss areas with different environmental characteristics (Aarau, Basel, Davos, Geneva, Lugano, Montana, Payerne, Wald). In total, 9651 adults (60%) participated in the cross-sectional investigation (part 1, 1991), consisting of the following standardized procedures: questionnaire (interview), forced expiratory lung function test, bronchial challenge with methacholine, atopy assessment (Phadiatop, unspecific total IgE), allergy skin tests, and endexpiratory CO-measurements. Subjects with a history of respiratory symptoms, increased bronchial reactivity, reduced lung function (FEV1/FVC < 80% predicted) and 150 healthy never-smokers were included in the subsequent diary study (part 2; n = 3281, 1992/93). Peak flow (morning and evening), symptoms, medication, personal activity and visits to the doctor were monitored. Across regions, annual mean values ranged from 9 to 52 mg/m3 (NO2) and 10 to 33 mg/m3 (PM10) respectively. Air pollution had effects on prevalence of dyspnea (+41% per 10 mg/m3 increment of the annual mean PM10, 95% CI 20-65%), on symptoms of chronic bronchitis (+31%, 10-55%), on FVC (-3.1%; -3.7 to -2.6%), and FEV1 (-1.1%; -1.7% to -0.5%), on the incidence of respiratory symptoms and the length of symptomfree intervals (11% change per 10 mg/m3 PM10), but not on the prevalence of asthma. Environmental tobacco smoke (ETS) showed impact on wheezing (OR 1.94; 1.39-2.70), asthma (1.39; 1.04-1.86), bronchitis (1.60; 1.24-2.08) and chronic bronchitis (1.50; 1.11-2.02). Health effects of moderate air pollution were confirmed in Switzerland. Although for the individual the relative risks are small, the public health impact may be considerable. An ongoing follow-up will investigate the mortality profile of the SAPALDIA cohort.

COPD is a disorder characterized by expiratory flow limitation that does not change markedly over periods of several months' observation. When the diagnosis is suspected, COPD patients should be submitted to full assessment and initiation of therapy. Initial assessment includes a complete history, a detailed physical examination, pulmonary function tests, a chest X-ray, and blood tests. Therapy of COPD aims at reducing symptoms, preventing exacerbations and preserving optimal lung function. Many COPD patients have a bronchospastic component and usually show some response to bronchodilator therapy. Anticholinergics, beta 2-agonists or theophylline are used as monotherapy or in combination. A subgroup of patients with COPD may benefit from oral long-term corticosteroid therapy. At prime diagnosis of COPD, a trial of oral steroid under optimal bronchodilator therapy is warranted in order to identify steroid responders early in the course of the disease. Stopping smoking is the most effective preventive measure and should be combined with complementary approaches such as eviction of environmental irritants, vaccines and prescription of antioxidants. Long-term oxygen therapy is beneficial in chronically hypoxemic patients. Respiratory rehabilitation uses a multidisciplinary approach aiming at decreasing dyspnea, increasing exercise tolerance and improving quality of life. Nocturnal home noninvasive mechanical ventilatory assistance can improve arterial blood gas tensions in patients with respiratory failure, but the long-term effect on survival is still under investigation. In selected patients, surgery (bullectomy, lung volume reduction, lung transplantation) may greatly improve pulmonary function.

Cough is one of the most prevalent symptoms of bronchopulmonary diseases. If cough persists ( > 6 weeks), further workup is mandatory. The most common causes of persistent cough in nonsmokers presenting with a normal CXR are postnasal drip due to chronic rhinitis-sinusitis, cough equivalent asthma or gastroesophageal reflux. The response to empirical therapy may confirm one of these etiologies. Other causes of chronic cough need further extensive workup involving radiologic, functional and endoscopic procedures.

The immediate effects and long-term results are reported of thoracoscopic pleurodesis in 225 patients (158 men, 67 women) treated for persistent or recurrent spontaneous pneumothorax. The procedure was performed by combined local and neurolept analgesia with direct visual exploration of the pleural space through a rigid thoracoscope. The technique included electrocoagulation of small pleural blebs, followed by regional application of fibrin and insufflation of talc powder. The main indications were a first event which persisted more than 7 days despite chest-tube suction drainage in 27% (n = 61) or a recurrent event in 73% (n = 164). The procedure provided primary success in 96.4% of the patients. Only 8 patients (3.6%) required surgical intervention including parietal pleurectomy. Perioperative complications were pharmacologically induced respiratory failure (n = 5), generalized subcutaneous emphysema (n = 8), bleeding by cutting adhesions (n = 5) and Horner's syndrome (n = 2). However, no fatal complications occurred which could be ascribed to the procedure and all patients were discharged from the hospital after an average of 12.3 days except one who died of pulmonary embolism 5 days after thoracoscopy. Long-term follow-up over a mean period of 4.1 years revealed an ipsilateral recurrence rate of 10.2% (n = 24), 16% of the patients complained of sporadic pains at the site of insertion, 51% still had diffuse thoracic pains and 2.4% reported occasional attacks of dyspnea. Spirometric lung function tests showed normal values in 89%. The immediate and longterm results show thoracoscopic pleurodesis with fibrin and talcum to be a safe and effective method for treatment of patients with persistent or recurrent pneumothorax.

The influence of moderate ambient ozone exposure on spirometric lung function and bronchial responsiveness was analyzed in 13 healthy adult nonsmokers and 11 asymptomatic smokers. The study was divided into an initial investigation at low atmospheric ozone concentrations of about 80 (range 68-102) micrograms/m3 and a subsequent similar testing at moderately elevated ozone concentrations above 140 (range 145-205) micrograms/m3. Overall there was a slight but significant impairment in forced expiratory volumes (p less than 0.002) at elevated compared with low ozone concentrations. Furthermore, a significant increase in bronchial responsiveness was shown, with a decrease in threshold dose for inhaled metacholine to produce a 50% fall in specific airway conductance (p less than 0.02). In both smokers and nonsmokers there was a similar change in lung function at ambient ozone concentrations, with more pronounced bronchial irritation in the smokers group. It is concluded that even moderately elevated ambient ozone concentrations can induce slight but significant ventilatory obstruction and an obvious increase in bronchial responsiveness in healthy adults. Although the minor impairment of lung function did not cause manifest acute respiratory problems, it still reduced maximal physical ventilation capacity. The results further support the assumption that air pollution may act as a primary trigger in the development of obstructive airway disease.

Different results have been observed in systematically analysing bacteriological cultures of (a) bronchial secretions aspirated during fiberoptic bronchoscopy and (b) of sputum. In a prospective study of 23 patients with chronic infections of the lower respiratory tract, bacteriological cultures of the sputum showed more bronchopathogenic strains than those of subsequently removed bronchial secretions. These different findings may be attributed to a bactericidal effect of topical anesthetics used during bronchoscopy. To evaluate the influence of anesthetics on the growth of microorganisms, several strains cultured from sputum specimens were exposed to various solutions of the most commonly used anesthetics. The growth of Haemophilus influenzae and Diplococcus pneumoniae was completely depressed by all the tested solutions and dilutions. Only Staphylococcus aureus and several strains of Enterobacteriaceae were resistant even to high concentrations of anesthetic solutions. The results suggest that specimens of bronchial secretions taken by routine fiberoptic techniques cannot be used for reliable bacteriological diagnosis of lower respiratory tract infections.

The immediate effect of physiotherapy and the effect of IPPB-inhalations in 18 patients with chronic obstructive lung disease and global respiratory failure have been investigated and discussed. The procedures (physiotherapy or IPPB-inhalations) were tested singly and in combination. Better results are obtained when physiotherapy is performed before IPPB-inhalation. A significant decrease in pCO2 and a significant rise in VC and FEV1 are observed, with unchanged pO2.

The efficacy of Broncho-Vaxom has been evaluated by a multicentric working group of physicians in 75 patients with chronic bronchitis using a randomized double-blind trial. Initial data of the selected patients showed no significant differences in history, previous medication, individual state and spirometric lung function values between the control group (n = 39) and the cases treated with the test medication (n = 36). After 30-day initial treatment both physician and patient favoured the active substance (p less than 0.01) although there was statistically no evidence of a curative effect measured by objective criteria. Longterm follow-up over a period of six months again revealed a more effective course in the Broncho-Vaxom group according to individual observations (p less than 0.05). In fact there was an impressive trend towards reduction of clinical symptoms with Broncho-Vaxom medication. However, statistical analysis of individual symptoms' scores and lung function tests did not show significant alterations within the two groups. Taking in account the complexity of bronchitic disease, statistical demonstration of a beneficial effect of Broncho-Vaxom with respect to clinical symptoms and lung function tests probably needs a longer observation period, a larger population and a choice of more sensitive methods.

In 60 selected patients affected by a limited stage of bronchial carcinoma according to clinical examinations, routine computed tomography and mediastinoscopy were performed to detect metastatic lymph-node involvement. Patients with histologically proven mediastinal lymph-node metastasis (stage N 2-3) subsequently were excluded from surgical therapy. As alternative diagnostic procedures four different strategies are discussed to estimate the greatest efficacy regarding costs and benefits in preoperative staging of malignant lung tumors: (1) primary thoracotomy, (2) routine mediastinoscopy, (3) thoracic CT-scanning and (4) CT-scanning combined with selective mediastinoscopy. Efficacy was then evaluated by the criteria of financial expenditure for each curative resection. As a result there are but small differences between the four diagnostic approaches and thoracic CT-scanning definitely does not reduce the overall costs of curative surgery or markedly improve the diagnostic yield. However, the combination of selected mediastinoscopy with CT-scanning at least increased comfort and safety in preoperative staging of patients without loss of sensitivity or specificity in detecting resectable tumors. This method should therefore be favoured for evaluating the resectability of bronchial carcinoma.

Puncture of the radial or cubital artery with a thin needle of 0.4--0.5 mm diameter connected to a glass capillary is a simple and non-invasive technique for obtaining samples for arterial blood gas analysis. Compared with the conventional sampling techniques using glass syringes and needles of larger calibers, the results, especially with regard to paO2 values, show very close agreement over a wide range from hypoxic to hyperoxic conditions (correlation coefficient r2 = 0.99) if the microsamples are analysed within 10 minutes. Delayed analysis after 30 minutes, however, shows marked underestimation of hyperoxic paO2 (greater than 150 mm Hg) with the microtechnique, whereas paO2 values below 100 mm Hg are still comparable to the macrosamples. The method described provides an accurate arterial blood gas analysis without discomfort or harmful side effects, especially in patients under treatment with anticoagulants.

In a prospective trial we studied the effect of nocturnal low-flow oxygen administration in 10 consecutive patients with obstructive sleep apnea. In 5 patients the clinical symptoms disappeared completely under nasal oxygen administration and hypoxic episodes decreased from an average of 28 to 3 per hour. In the remaining 5 patients nasal oxygen alone was not sufficiently effective. After insertion of a transtracheal catheter for nocturnal oxygen delivery, however, in 4 of these 5 patients (one patient refused the procedure) clinical symptoms improved and hypoxic episodes were reduced to 3 per hour (48/h without oxygen, 34/h with nasal oxygen). The favourable effect of transtracheal oxygen therapy may be due to the improved oxygenation provided by this technique, as well as to a "pneumatic splint" as a result of increased positive pressure in the central airways during prolonged apneic episodes. Thus, transtracheal oxygen therapy can be considered an efficient alternative to nasal CPAP in patients with severe obstructive sleep apnea syndrome.

In 100 patients with lung cancer the diagnostic procedure, results of clinical staging and therapeutic sequelae were analysed retrospectively and compared to a similar group of patients 10 years previously. During the 10 years' interval there was a remarkable shortening of the time between the onset of symptoms and the diagnosis, from 20 weeks to the present 10 weeks. Despite this acceleration the number of patients undergoing curative surgical resection increased only from 15 to 17%. Inoperability was still due to general condition in 14%, impaired lung function in 7%, advanced tumor stages with metastasis in 52% and local inoperability in 10%. Of the 77 patients with specific tumor related symptoms only 18 were in the prognostically favourable stage I, whereas in the asymptomatic group early stage I was observed in 13 out of 23 patients. We conclude that an improvement in early detection of lung cancer may be achieved by periodical screening of the high risk population, rather than by focusing on the onset of the first symptoms.

Patients with acute severe respiratory insufficiency can only be correctly monitored, treated and nursed in a well-equipped intensive care unit staffed with well-trained personnel. Qualified doctors and nursing staff are more important for the monitoring and assessment of the patient's symptoms than highly sophisticated electronic monitoring systems. Continuous controls of vital and mechanical functions are however essential , as are the services of well-run laboratories. Treatment calls, above all, for the use of efficient and reliable respirators capable of adjustment to suit the impaired breathing. The quality of nursing and the success of intensive medical care measures are best ensured by well-designed layouts, strict adherence to sensible and appropriate hygienic techniques, continuous and practice-related further education for personnel, and unrestricted communication inside and outside the intensive care unit.

The purpose of investigating pulmonary gas exchange and pulmonary circulation is detection of functional abnormalities of the cardiorespiratory system. Other than clinical features, a number of specialized methods used today are of high accuracy and therefore serve to recognize early disorders and to quantify functional impairment. In clinical practice arterial blood gas analysis and the measurement of diffusing capacity are sensitive screening tests for patients with acute and chronic respiratory failure and thus have important diagnostic and therapeutic implications (e.g. indication for oxygen therapy, mechanical ventilation, chest physiotherapy, specific drug regimen etc.). Spiroergometry and right heart catheterization, as the more invasive methods, are useful tests in evaluating overall cardiopulmonary function to detect limiting factors in physical performance (e.g. thoracic surgery, occupational diseases, sport medicine).

The clinical entity of chronic respiratory insufficiency involves a variety of lung diseases with different etiology. Diagnosis, treatment and follow-up are mainly a problem of ambulatory medicine. The most common representative is the patient with chronic obstructive lung disease. The wide array of diagnostic tools makes the selection of appropriate tests difficult for the general practitioner. The clinical findings, as the most important aspect, together with a simple spirometric test (VC and FEV1), however, provide the physician with sufficient parameters to evaluate the current status. Blood gas analysis are indispenable, but can be performed at lengthy intervals. The main therapy relies on selective beta-agonists in combination with steroids. For long-term administration of steroids, however, inhaled steroids should be preferred. Antibiotics should be used liberally and without delay. Cardiac therapy is an important cornerstone in the treatment of chronic respiratory insufficiency. The frequency of glycoside intolerance makes diuretics the ideally suited drug for treatment of concomitant cardiac insufficiency. It is advantageous to use consistent inhalation therapy for drug administration, mainly due to the milder systemic side-effects. A choice must be made between the simple electric nebulizer or the more demanding IPPB-respirator, which requires more demanding patient selection. Both types can be leased through Cantonal institutions, which also provide for regular control of inhalation techniques and maintenance of the inhalation devices. Physiotherapy plays an important part in the instruction of patients as well as providing them with psychological assistance and support in everyday problems. Regular monthly controls by a physician with a standardized questionnaire have proven most useful in guiding the patients and adjusting therapy to individual needs. The frequency of hospitalization can only be reduced by observing all the above mentioned factors.

Weaning from the respirator is obviously the most time-consuming phase in mechanically ventilated patients. Major problems still arise in the early detection and elimination of risk factors which may impair adequate spontaneous breathing. Detailed physiological consideration of the respiratory disability should distinguish between defects in lung mechanics and inspiratory muscle failure. Thus, proper mechanical ventilation can be established in order to restore or to train the respiratory muscles (IPPB versus IMV/CPAP principle) during the weaning period. Prior to any extubation, the data on clinical state, results of blood gas analysis and pulmonary mechanics, as well as special tests for estimation of inspiratory muscle strength, are of definite value.

In patients with chronic respiratory insufficiency the treatment of the underlying pulmonary disease is of primary importance. However, many patients often also need symptomatic management to recompensate or stabilize impaired pulmonary gas exchange. The most suitable measures for this purpose are (1) ventilatory support by periodic intermittent positive pressure breathing (IPPB), (2) long-term oxygen administration and (3) respiratory stimulant drugs. IPPB provides good results if restricted to well defined indications (paO2 below 60 mm Hg, paCO2 above 45 mm Hg, forced expiratory volume [FEV1] below 40% of vital capacity or below 1000 ml). Long-term domiciliary oxygen therapy for at least 15 h daily prevents the early decompensation of cor pulmonale and improves physical performance. With the introduction of industrial O2-concentrators this form of therapy becomes more practicable and less expensive compared with the conventional method delivering compressed oxygen. However, the indication should be confined to patients with chronic and severe hypoxemia (paO2 below 50 mm Hg), pulmonary hypertension and secondary polycythemia. Respiratory stimulant drugs are useful in protecting patients from central respiratory depression during oxygen breathing. Aminophylline seems to be the most suitable drug simultaneously acting as a bronchodilator and vasodilator in the pulmonary circulation. To achieve a potent stimulant effect, serum theophylline levels above 10 microgram/ml through repeated intravenous administrations of aminophylline are required. Individual differences in the pharmacokinetic action of theophylline may sometimes need drug monitoring to prevent toxic side effects.

Several lung function tests are capable of detecting typical functional abnormalities in pulmonary emphysema, such as reduced elastic recoil of lung tissue, elevation of intrathoracic gas volumes, expiratory bronchial collapse or uneven patterns of ventilation. The measurement of elastic recoil by means of an esophageal catheter also seems to be a reliable technique for detecting early stages of emphysema, but its use for routine clinical investigations remains impracticable. The elevation of intrathoracic gas volumes determined by body plethysmography or helium dilution technique may sometimes be influenced by reversible bronchial obstructions or additional restrictive ventilatory defects. Expiratory collapse of the intrathoracic airways, however, proves to be a regular finding in advanced pulmonary emphysema. It results from decreased stability of the peripheral and central bronchial wall as well as from a shifting of bronchial and transmural pressure gradients to the peripheral airways. The occurrence of a pressure dependent expiratory stenosis can easily be demonstrated by the spirometric flow-volume curve during forced expiration, thus differentiating patients with asthma from those with chronic bronchitis and emphysema. The minimal program for detection and evaluation of emphysematous alterations of the lung by functional tests should consist in the measurement of intrathoracic gas volumes, recording of the forced expiratory volume and the analysis of the flow-volume curve.

The effect of home long-term oxygen therapy has been evaluated in 70 patients (52 men and 18 women) with chronic respiratory insufficiency due to chronic obstructive pulmonary disease. The mean duration of the observation period was 17.5 months, lasting at least 6 months and in a few cases over 40 months. The cumulative death rate was 22.6% in the first 12 months, 36.5% after two years and 40.7% in the third year. Compared to a previous period of 19.5 months there was an obvious reversal in hypoxemia, an increase in physical capacity and a reduction in the hospitalization rate. Patients with marked respiratory failure and with the clinical features of the "blue bloater" type of chronic bronchitis responded better to the home oxygen therapy than a group of "advanced pink puffers" with hypercapnia and high pulmonary arterial pressure. The present results do however confirm the beneficial effects of long-term domiciliary oxygen administration, and should encourage critical use of this new therapeutic regimen according to the indications so far recommended.

Sustained success was achieved in treating a 40-year-old patient who had had severe progressive thoracic kyphoscoliosis since childhood and developed cardiorespiratory failure with terminal alveolar hypoventilation and hypoxemia due to acute pulmonary infection. On emergency admission to this hospital mechanically controlled ventilation by tracheostomy tube produced a remarkable improvement in cardiorespiratory function. Weakness of the respiratory muscles made complete disconnection from ventilatory support impossible. Instead of positive pressure ventilation by tracheostomy tube with resultant patient invalidity, nighttime external negative pressure ventilation with an Emerson chest respirator was started leaving the patient free for daytime activity. This type of ventilation is a simple, effective and well tolerated long-term treatment at low cost. The patient has been using it nightly at home for over 6 months and no problems have arisen. These findings show that intensive care is indicated in patients with severe thoracic kyphoscoliosis and cardiorespiratory failure since long-term treatment of terminal hypoventilation and cardiorespiratory failure is possible with a cheap and simple nocturnal ventilation system.

The diagnosis of respiratory failure is based on pathological findings in arterial blood gas analysis. Thus, even in emergent cases with acute pulmonary disorders, rapid differentiation of the amount and nature of the respiratory impairment is possible. Furthermore, evaluation of the blood gas analysis may be an essential factor in the choice of therapeutic procedures. Hypoxia should be treated by strictly controlled oxygen administration, to avoid further respiratory depressant effects. Patients with acute and progressive respiratory acidosis usually need artificial ventilation by volume- or pressure-cycled respirator. Some important modifications of ventilation are recommended with a view to improving pulmonary gas exchange and decreasing the incidence of complications, especially during the long-term treatment with respirators.

Chylothorax with bilateral hilar and mediastinal lymphomas has been observed in a 27-year-old patient. Further clinical investigations revealed sarcoidosis with involvement of the mediastinal lymphnodes, the bronchial mucosa and the pleural mesothelium. It is suggested that the chylothorax is a complication of sarcoidosis, although pleural effusions of chylus have thus far been reported only in traumatic or malignant diseases of the mediastinum. The pathogenesis was unclear until exploration of the pleural space by thoracoscopy showed an intact and unaffected thoracic duct. During longterm treatment with corticosteroids, supported by several pleural drainages, the chylothorax and other concomitant symptoms gradually regressed.