Search

The purpose of the lung is intrapulmonary gas exchange. The circulatory system delivers the respiratory gases to the tissue. The ventilatory pump however is responsible for the circulation of air between the lungs and the ambient atmosphere. Due to better diffusing capabilities, hypercapnia always is a result of pump failure and little dependent on the lung. Ventilatory failure, either compensated with an increased demand on the muscles or decompensated with an additional increase in pCO2, should be separated from lung failure where primarily oxygen exchange is involved. Decompensated hypercapnic ventilatory failure is then the indication for intermittent mechanical ventilation. The pCO2, either arterial or transcutaneously registered together with the noninvasive evaluation of the mouth occlusion pressures during tidal breathing and during a maximal inspiratory effort, define well the severity of ventilatory failure. In acute on chronic ventilatory failure, noninvasive mechanical ventilation in three randomised and controlled studies resulted in a better survival compared to intubation. To fulfil certain weaning criteria is no longer required in difficult to wean patients, as a transfer from invasive to noninvasive mechanical ventilation can be performed if only cooperativity is preserved together with a minimal capacity of spontaneous breathing. Weaning will thereafter occur by progressive relief from intermittent noninvasive ventilation. 2300 difficult to wean patients in Germany should profit from this approach. Chronic ventilatory failure as a result of neuromuscular disease or scoliosis of the thoracic spine are the classical indications. COPD and myasthenia gravis are under discussion as indications for intermittent mechanical ventilation with an increasing tendency to ventilate. Epidemiological data however can only be roughly estimated due to the heterogeneity of indication and selection of the patients.

Background: Nocturnal mechanical ventilation (NMV) can reduce symptoms of hypoventilation and improve gas exchange in patients with chronic respiratory failure but there is no data concerning the impact of nocturnal mechanical ventilation on daily activity. We prospectively measured daily activity as judged by total steps per day., Patients and Methods: Thirty stable patients (17 men, mean age 55.2 years, pCO2: 62.3 +/- 9.0 mmHg) with chronic respiratory failure., Diagnosis: Kyphoscoliosis (n = 11), COLD (n = 7), neuromuscular diseases (n = 6), post-tbc sequelae (n = 6). Applying a pedometer over a 7 day period before and 3 months after initiating nocturnal mechanical ventilation the steps per day were counted. We also obtained arterial blood gases and applied the St. George's Respiratory Questionnaire (scoring range from 0 = complete health to 100 = worst possible)., Results and Conclusions: The daily activity in patients with hypercapnic respiratory failure as judged by the total amount of steps per day increased by 120% after 3 months of nocturnal mechanical ventilation (from 1606.9 +/- 1341.3 to 3535 +/- 1813.8 steps per day, p < 0.0001). This was associated with a significant improvement in daytime blood gases and quality of life (QoL) as judged by questionnaire (total score: from 61.3 +/- 14.9 to 48.3 +/- 18.7, p = 0.0006). However no correlation between steps per day and QoL was found.

Background: The purpose of this study is to assess quality of life in patients with chronic respiratory failure who require home mechanical ventilation (HMV)., Patients and Methods: Patients with COPD (n = 20), scoliosis (n = 20), neuromuscular diseases (n = 20) and others (n = 7) were examined. A specific questionnaire containing forms for the patient, the physician and for the relatives was developed according to the formulation of the question (Fragebogen zur chronischen Heimbeatmung = FCH, Interview zur chronischen Heimbeatmung = ICH). In addition to that the Hospital Anxiety and Depression Scale (HAD) and the Asthma Quality of Life Questionnaire were used. Arterial blood gas tensions, pulmonary function and inspiratory mouth occlusion pressure were studied., Results: Quality of life in patients with scoliosis and neuromuscular diseases is improved during HMV compared to patients with COPD who especially are impaired with regard to psychological and functional conditions. Correlations with physiological parameters and with the compliance could not be observed., Conclusion: Despite progression of the disease HMV enhances quality of life in patients with scoliosis and neuromuscular diseases. The outcome in COPD is less evident. Therefore the indication must be considered more critically.

Background: In patients with hypercapnic respiratory failure due to restrictive lung diseases home mechanical ventilation leads to improvement of daytime blood gases and symptoms. In this paper we regard the possible pitfalls and complications associated with intermittent mechanical ventilation in patients with kyphoscoliosis., Patients and Methods: From 1990 to 1994 we treated 30 patients suffering from severe kyphoscoliosis with home mechanical ventilation., Results and Conclusions: 1. As our cases show in the prehospital phase before initiating home mechanical ventilation there is still room for the outpatient pneumologists to improve their knowledge and awareness of symptoms and treatment of chronic respiratory failure. 2. In the subsequent inpatient phase and specialised center must be aware and experienced in regarding possible problems inherent with home mechanical ventilation. 3. After discharge during chronic home mechanical ventilation a good cooperation between the center, patient, relatives, general services and general pulmolgists is necessary. The centers should offer training courses for the caring persons and general pneumologists.

Background: Proportional assist ventilation (PAV), a new mode for assist ventilation, allows the patient not only to trigger the ventilator but enables him to keep his breathing pattern. The basis of PAV is a positive feed back between patient and ventilator., Patients and Method: PAV was applied in 6 patients, who were under long-term ventilation and who were stable. The ventilator was adjusted to compensate for the endotracheal tube, different parts between 90 and 40% of resistance and elastance were assisted. Airway pressure, flow and tidal volume were measured. PAV was compared with pressure support ventilation (PSV)., Result: No difference in blood gases were found in PAV as compared to PSV. Airway pressure were lower in PAV than in PSV (10.4 +/- 3.3 cm H2O vs. 18.8 +/- 5.9 cm H2O in PSV). Breathing frequency was higher (22.4 +/- 8.1 vs. 15.8 +/- 5.9 in PSV)., Conclusion: The higher breathing frequencies in PAV were associated with the underlying diseases and resulted in a better synchronisation with the respiratory center output.

Introduction: Noninvasive intermittent ventilation is usually performed in patients with severe ventilatory pump disorder. From 1988 to 3/1995 we treated 163 patients with the aim of home mechanical ventilation (HMV)., Patients and Results: In March 1993 115 of these 163 patients practiced HMV, 22 had already died and 26 had rejected or broken off ventilation therapy. The 115 patients were classified in three main diagnostic groups: Scoliosis or chest wall disease (n = 76), COPD (n = 11) and neuromuscular disease (n = 28). The mean pCO2 at rest of all patients before ventilation therapy was 56 (+/- 12) Torr and fell to 46 (+/- 5) Torr in the course of therapy. The maximum statical inspiration pressure PImax rose from average 3, 8 (+/- 2, 3) to 4, 9 (+/- 2, 0) kPa. There was a probability of surviving two years after onset of ventilation therapy of 85% in the scoliosis group, of 60% in the neuromuscular group and of 30% in the COPD group., Conclusions: According to results of others home ventilation therapy was very successful in patients with chest wall disease. In some patients with neuromuscular disorder quality of life could be improved and life prolonged. Only half of the COPD patients could be treated successfully, whereas the other half had no benefit from noninvasive ventilation therapy.

Background: There are only small experiences with mechanical ventilation via nasal mask in childhood., Patients and Methods: Eleven patients using NIPPV (9 patients aged 4 to 18 years and 2 patients with cystic fibrosis aged 20 and 25 years)., Results: NIPPV was effective in all 11 patients. Seven patients needed supplemental oxygen. Theophyllin, Almitrin and Salbutamol could support the nasal ventilation in special conditions., Conclusion: Intermittent ventilation via nasal mask is a noninvasive and effective treatment of chronic respiratory failure in childhood. Monitoring with continuous pulse-oximetry is necessary.

Background: Fully informed patients were willing to start with IPPV., Patients and Methods: Twenty-three patients with amyothropic lateral sclerosis (ALS) were treated with noninvasive intermittent mechanical ventilation (7 women, 16 men, mean age 59 years). The major symptoms were dyspnoe, heavy sleep disruption resulting in severely reduced quality of life., Results: Their symptoms improved. The blood gases normalized during spontaneous breathing. They remained stable, despite a rapid decrease in respiratory force. Thirteen patients died, 6 during an acute event, 4 during bronchopulmonary infection and 3 stopped therapy, when they were fully ventilator dependent., Conclusion: We conclude that respiratory symptoms and quality of life can be improved by home intermittent mechanical ventilation. Indication should therefore be made earlier.