Respiratory dysfunction in ventilated patients: can inspiratory muscle training help?

Respiratory muscle dysfunction is associated with prolonged and difficult weaning from mechanical ventilation. This dysfunction in ventilator-dependent patients is multifactorial: there is evidence that inspiratory muscle weakness is partially explained by disuse atrophy secondary to ventilation, and positive end-expiratory pressure can further reduce muscle strength by negatively shifting the length-tension curve of the diaphragm. Polyneuropathy is also likely to contribute to apparent muscle weakness in critically ill patients, and nutritional and pharmaceutical effects may further compound muscle weakness. Moreover, psychological influences, including anxiety, may contribute to difficulty in weaning. There is recent evidence that inspiratory muscle training is safe and feasible in selected ventilator-dependent patients, and that this training can reduce the weaning period and improve overall weaning success rates. Extrapolating from evidence in sports medicine, as well as the known effects of inspiratory muscle training in chronic lung disease, a theoretical model is proposed to describe how inspiratory muscle training enhances weaning and recovery from mechanical ventilation. Possible mechanisms include increased protein synthesis (both Type 1 and Type 2 muscle fibres), enhanced limb perfusion via dampening of a sympathetically-mediated metaboreflex, reduced lactate levels and modulation of the perception of exertion, resulting in less dyspnoea and enhanced exercise capacity.

[What must we do for patients with ALS in the process of their decision making on TIPPV?].

Patients with amyotrophic lateral sclerosis (ALS) must stand at crossroads when their disease advances causing respiratory failure; they have to decide whether or not to use tracheal intermittent positive pressure ventilation (TIPPV). Because the decision may devide their lives into alive or dead, appropriate information should be provided to the patients and their family before they make the decision. The information they would require include not only on medical care but also on social or economical issues if they should be on ventilator dependent life. In 2004 I had a research about the presenting the diagnosis of ALS. Words of patients and their family taught me that how poor the information we have given on presenting the diagnosis about ALS. In the United States, social workers assist patient decision making. In Japan, on the other hand, it has not been acknowledged that professions other than physicians should also be concerned in the patients making decision on medical treatments. Physician alone cannot deal with the needs of the patients and their family in the decision making. Not only physicians but also co-medical staff, for example, social workers, must take a part of the process of providing appropriate information.

Outcome and attitudes toward home tracheostomy ventilation of consecutive patients: a 10-year experience.

OBJECTIVES: To describe survival, predictors of long-term outcome and attitudes in patients treated at home by tracheostomy-intermittent positive-pressure ventilation (TIPPV) for respiratory failure during a 10-year period (1995-2004). METHODS: Seventy-seven consecutive patients were treated by TIPPV at home. Patients were divided into three groups: neuromuscular, pulmonary, and non-pulmonary patients. Effects of TIPPV on survival, factors influencing outcome after TIPPV, and attitudes of patients and caregivers regarding mechanical ventilation were studied. RESULTS: Forty-one patients (53%) were neuromuscular, 19 (25%) were affected by pulmonary diseases, and 17 (22%) by non-pulmonary diseases. The median survival time after TIPPV in the group was 49 months (range 3-149 months). There was statistically significant longer survival in neuromuscular compared to pulmonary patients (p=0.006), and a trend toward longer survival for non-pulmonary when compared to pulmonary patients (p=0.048). Chronic obstructive pulmonary disease (COPD) patients (n=14) showed the poorest outlook (median survival 26 months, range 3-45 months) and the highest number of emergency readmissions to hospital. The median survival in amyotrophic lateral sclerosis (ALS) patients was 49 months (range 30-61), lower than the whole group of neuromuscular patients. Major tracheostomy complications were low: 2.6%. Multivariate analysis showed that COPD and ALS patients had a three-fold higher risk of death than patients with other diagnoses. Lastly, 64 patients (83%) were pleased they had chosen TIPPV and 69 (90%) would choose it again. Forty-two caregivers (55%) were pleased the patients had chosen home ventilation, but 29 (38%) reported major burdens. CONCLUSIONS: TIPPV is well-received by the patients, is safe, and provides survival for long periods of time. Underlying conditions (COPD and ALS) might represent important prognostic factors for survival.

Environmental factors influencing weaning of a young child from mechanical ventilator support.

We examined the contribution of physiologic and environmental variables to the process of weaning a child with chronic respiratory failure from mechanical ventilation support. Surveillance measures, e.g., blood oxygenation, were obtained from a 6-year-old child with multiple medical and developmental disorders who received three different rates (24, 22, and 20 tidal volumes per minute) of intermittent mechanical ventilation. Direct observations were used to calculate rates of aberrant behavior, e.g., aggression toward self, for task versus play settings within the intermittent mechanical ventilation rates. Rates of aberrant behavior and adult responses were tabulated from videotaped observations for task, attention, and no attention settings. The greatest rate of aberrant behavior occurred during tasks compared with play activities, regardless of whether attention was provided while playing. Adults also responded more often to aberrant behaviors during task versus play conditions. Clinical implications are discussed concerning the inclusion of developmental and behavioral variables during weaning from mechanical ventilation.

[Patient-related rejection of nasal IPPV therapy. Patients, reasons, follow-up]. / Patientenbedingte Ablehnung der nasalen IPPV-Therapie. Patienten, Gründe, Verlauf.

PATIENTS: We retrospectively analysed the course of 33 patients who had rejected nasal IPPV-therapy (1988 to February 1996). RESULTS: The death-rate was higher (48%) compared to nasal IPPV patients in the same time (18%). The patients were divided in 3 main diagnostic groups (COPD, restrictive thoracic wall, neuromuscle disease). We observed the highest death-rate in COPD patients (66%) and the lowest death-rate in the group with scoliosis or chest wall disease (23%). This is the same result tendencially as in patients with nasal IPPV (mortality-rate COPD 66%, restrictive chest wall 6%).

[Prospective study of the quality of life in intermittent self-ventilation]. / Eine prospektive Untersuchung der Lebensqualität unter intermittierender Selbstbeatmung.

PATIENTS AND METHOD: We assessed quality of life for 17 patients (age 14 to 74 years) before and during intermittent (nightly) nasal home mechanical ventilation with a standardized questionnaire (SF 36, Medical Outcomes Trust, Boston, USA). Underlying diseases were amyotrophic lateral sclerosis, bronchiectasis, kyphoscoliosis, pulmonary emphysema, muscular dystrophy and sequelae of tuberculosis. Blood gas and lung function data were collected during every examination. RESULTS: We observed statistically significant increases for items of general health, mental health, vitality and capillary oxygen partial pressure. CONCLUSION: The SF 36 allows to assess quality of life for patients under intermittent mechanical ventilation at home.

[Quality of life in home ventilation]. / Lebensqualität bei Heimbeatmung.

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.

Patient experiences during respirator treatment--reason for intermittent positive-pressure ventilation treatment and patient awareness in the intensive care unit.

Patient awareness of intermittent positive-pressure ventilation (IPPV) treatment in the ICU was studied in 304 patients. These ICU patients were divided into three groups: those treated for internal medical diseases (IMD; n = 129), patients admitted after major surgical procedures (MSP; n = 126), and patients treated for trauma (T; n = 49). All patients were interviewed 2 months to 4 yr after IPPV treatment. The IPPV period was recalled by 52% of all patients. The awareness of the treatment was similar in the IMD (51%) and MSP (59%) groups, but was significantly lower in the T group (37%; p less than .01). The ability to recall the IPPV treatment was reduced in patients with head injuries, those unconscious on admittance, and in elderly individuals. Treatment awareness was found to increase with the duration of the IPPV period in the IMD and T groups. Preoperative information of the treatment, given to elective surgical patients in the MSP group, did not increase treatment awareness.