Reversibility of airways obstruction in bronchiectasis.

Patients with airways obstruction and bronchiectasis were investigated for features of allergic disease and for reversibility of airways obstruction in respinse to inhaled and intravenous salbutamol. There was a 26% increase in PEFR and a 16% increase in FEV1 after inhaled salbutamol, and the response to the intravenous drug was not significantly better than that to the inhaled. Those patients who responded to bronchodilators could not be identified by clinical or immunological features.     

Adjunct treatment with yoga in chronic severe airways obstruction.

Eleven patients with severe chronic airways obstruction were given training in yogic breathing exercises and postures. A matched group of 11 patients were given physiotherapy breathing exercises. Both groups of patients were followed up at monthly intervals for nine months with pulmonary function tests, tests of exercise tolerance, and inquiry into their symptoms. After training in yoga the mean maximum work increased significantly by 60.55 kpm; whereas no such rise occurred after training in physiotherapy. This objective improvement was associated with symptomatic improvement in a significantly higher number of patients given training in yoga.     

Characteristics of wheeze during histamine-induced airways obstruction in children with asthma.

BACKGROUND--An automated system has been developed for the detection of sound patterns suggestive of airways obstruction in long term recordings. The first step, presented here, was tracheal sound recording during histamine-induced airways obstruction. METHODS--The tracheal sounds of 29 children aged 8-19 years with asthma were recorded during airways obstruction caused by histamine inhalation using a system for continuous respiratory telemetry and computer analysis. Sound patterns were analysed, classified, and related to airways obstruction measured by lung function tests based on the forced expiratory volume in one second (FEV1). RESULTS--Five sound patterns were identified, one dominant sensitive and four specific to a fall in FEV1 of > 20%. The presence of at least one of three specific sound patterns during unforced respiration predicted a fall in FEV1 of > 20% in 87.5% of the subjects. The inspiratory and expiratory sound patterns were almost equally informative of airways obstruction. CONCLUSIONS--Wheezes can be differentiated with more precision than is currently accepted. Tracheal sound patterns are sensitive and specific predictors of histamine-induced airways obstruction. These patterns are neither invariably nor proportionally related to the results of lung function testing. However, they can be used for detection of airways obstruction on the basis of their presence or absence.     

Compliance with oral corticosteroids during steroid trials in chronic airways obstruction.

BACKGROUND: Corticosteroid trials are an important part of the assessment of patients with chronic airways obstruction, but false negative results will occur if the treatment is not taken. To determine compliance low dose phenobarbitone has been used as a marker. METHODS: Thirty six patients referred to a chest clinic for assessment of their airways obstruction were studied. They were instructed to take eight capsules (each containing 5 mg prednisolone and 0.5 mg phenobarbitone) per day for two weeks. The response was assessed by home peak flow monitoring and clinic spirometric tests. Plasma phenobarbitone levels were measured after the trial to enable calculation of the dose to plasma concentration ratio (level to dose ratio, LDR) and the result was compared with the reference range for fully compliant individuals. RESULTS: Five patients defaulted from follow up, 23 had LDR values within the expected range, and eight had low LDR values consistent with poor compliance. The nine patients with steroid responsive disease (> 20% improvement in peak flow or spirometric parameters) all had LDR values in the expected range. CONCLUSION: Excluding those who defaulted whose compliance must be questionable, eight (26%) patients did not fully comply with the steroid trial. Not all patients who fail to respond to a two week home steroid trial have a steroid "unresponsive" disease.     

Functional upper airways obstruction: two patients with persistent symptoms.

Functional upper airways obstruction is caused by vocal cord dysfunction and classically occurs in paroxysms closely resembling acute asthmatic attacks. We present two cases in which the symptoms and signs of the vocal cord dysfunction demonstrate very little variability with time. We suggest that as part of this disorder, a syndrome of chronic unremitting symptoms may occur.     

Blood lactate and respiratory muscle fatigue in patients with chronic airways obstruction.

Blood lactate concentrations were measured in five patients with chronic airways obstruction after 10 minutes' sustained maximal voluntary ventilation (SMVV) with end-tidal carbon dioxide tension kept constant and after a 12-minute walk. No patient showed a significant rise in blood lactate after SMVV but all showed evidence of low-frequency fatigue of the sternomastoid muscle. After a 12-minute walk three patients showed a significant rise in blood lactate and two of them also had evidence of low-frequency fatigue of the sternomastoid muscle. The absence of a rise in blood lactate after SMVV may be due to the fact that in patients with chronic airways obstruction ventilation is limited by airflow obstruction to a level where only a small muscle mass is used, or where the aerobic capacity of the respiratory muscles is not exceeded.     

Exertional dyspnoea in patients with airway obstruction, with and without CO2 retention

BACKGROUND: Dyspnoea is a common and disabling symptom in patients with cardiopulmonary disease. Unfortunately the mechanisms that produce dyspnoea are still poorly understood. The relationship between dyspnoea and the load on the ventilatory muscles, chemical drive, and ventilatory indices was therefore assessed in patients with obstructive pulmonary disease during an incremental exercise test. METHODS: Fifty patients with a wide range of obstructive pulmonary disease (mean forced expiratory volume in one second (FEV1) 66.1 (28.8)% predicted) performed an incremental cycle ergometer test. A subdivision was made between subjects with CO2 retention (delta PaCO2 > or = 0, n = 22) and subjects without CO2 retention (delta PaCO2 < 0, n = 28) during exercise. During the test dyspnoea (Borg score), oesophageal pressures (mechanical load on the ventilatory muscles (time tension index (TTI), blood gas tensions, and minute ventilation were measured. Correlations for changes in mechanical and chemical factors with changes in dyspnoea score were calculated to assess relevant factors. An analysis of covariance was used to examine whether there was a relationship between dyspnoea score and each of these factors and whether this relationship was different between the subgroups with and without CO2 retention. Multiple regression analysis was used to assess the independent effect of each parameter on dyspnoea sensation. Furthermore, the amplitude of pleural pressure swing ((Pi + Pe)act) generated at maximal work load (Ptot, an indication of the load on all respiratory muscles) was calculated. Analysis of covariance was used to assess whether there was a relationship between tidal volume (VT) and Ptot and whether this relationship was different between the groups (slopes are an expression of the length-tension inappropriateness, LTI). RESULTS: In the total group and the group without CO2 retention a significant correlation between dyspnoea and the increase in the inspiratory time tension index (TTIi) was present. In the group with CO2 retention a significant correlation was seen between dyspnoea and delta PaCO2. The factors delta PaO2, delta VE%MVV and delta (VT/Ti) showed a correlation with a p value of < or = 0.10 both in the total group and in those without CO2 retention. In an analysis of covariance the relationship between dyspnoea score and delta PaCO2 appeared to be significantly different between the two subgroups, being more pronounced in the group with CO2 retention. No other relationships with change in dyspnoea score were found. There was no significant relationship between VT and Ptot in the total group nor in the two subgroups, indicating some length-tension inappropriateness in both groups. CONCLUSIONS: In patients with distinctive pulmonary disease who are normocapnic or hypocapnic the mechanical load (delta TTIi) and length-tension inappropriateness (LTI) on ventilatory muscles seem to be the main determinant of exertional dyspnoea. As soon as hypercapnia occurs, this seems to override all other inputs for dyspnoea.     

Respiratory obstruction in the newborn associated with increased volume and opacification of the hemithorax

Respiratory obstruction in the newborn can be associated with retained fetal pulmonary fluid if the obstruction was present in utero. The chest roentgenogram demonstrates increased volume and radiopacity of the affected lung. Two patients in respiratory distress with these roentgenographic manifestations are presented. The diagnostic approach to this problem is discussed.     

A clinicopathological study of fatal chronic airways obstruction.

A clinicopathological study of 21 patients who died as a result of chronic airways obstruction was carried out. Thirteen patients had been in right ventricular failure for at least one year before death and the other eight patients did not have right ventricular failure. The patients with long-standing right ventricular failure died at a younger age, on average, than those without failure. There were no significant quantitative differences between the two groups in the length of history of chest disease, blood gas estimations, respiratory function tests or degree of polycythaemia. The group with right ventricular failure had significantly larger mean right and left ventricular weights than the group without failure, but there were no significant differences in amounts of emphysema, size of bronchial mucous glands, proportion of small airways lumen in the lung or number of thick-walled peripheral lung vessels between the two groups. The findings did not support the division of this series of patients, with fatal chronic airways obstruction, into two distinct groups broadly defined as 'emphysematous' and 'bronchitic', either clinically or pathologically. A history of right ventricular failure correlated well with the finding of right ventricular hypertrophy at necropsy. Electrocardiographic evidence of right ventricular hypertrophy was found to correspond with the size of the right ventricle at necropsy in 66% of cases. The radiographic diagnosis of emphysema proved an accurate assessment when compared to the necropsy findings, and radiographic estimations of right ventricular enlargement were accurate in 65% of cases. Histological evidence of acute bronchitis was present in 20 of the 21 patients (95%), and five patients showed histological evidence of minor pulmonary thromboembolism. Ten patients in the series showed an increase in the weight of the left ventricular as well as the right ventricle.     

Determinants of expiratory airflow in patients with chronic airways obstruction

This paper examines the relationship between the intrathoracic and bronchial pressures and the flow time course during forceful expiration in patients with severe chronic airways obstruction and tracheobronchial collapse.     

Respiratory mechanics during sevoflurane anesthesia in children with and without asthma.

We studied lung function in children with and without asthma receiving anesthesia with sevoflurane. Fifty-two children had anesthesia induced with sevoflurane (up to 8%) in a mixture of 50% nitrous oxide in oxygen and then maintained at 3% with children breathing spontaneously via face mask and Jackson-Rees modification of the T-piece. Airway opening pressure and flow were then measured. After insertion of an oral endotracheal tube under 5% sevoflurane, measurements were repeated at 3%, as well as after increasing to 4.2%. Respiratory system resistance (Rrs) and compliance during expiration were calculated using multilinear regression analysis of airway opening pressure and flow, assuming a single-compartment model. Data from 44 children were analyzed (22 asthmatics and 22 normal children). The two groups were comparable with respect to age, weight, ventilation variables, and baseline respiratory mechanics. Intubation was associated with a significant increase in Rrs in asthmatics (17% +/- 49%), whereas in normal children, Rrs slightly decreased (-4% +/- 39%). At 4.2%, Rrs decreased slightly in both groups with almost no change in compliance system resistance. We concluded that in children with mild to moderate asthma, endotracheal intubation during sevoflurane anesthesia was associated with increase in Rrs that was not seen in nonasthmatic children. IMPLICATIONS: Tracheal intubation using sevoflurane as sole anesthetic is possible and its frequency is increasing. When comparing children with and without asthma, tracheal intubation under sevoflurane was associated with an increase in respiratory system resistance in asthmatic children. However, no apparent clinical adverse event was observed.