ABSTRACT
Acute ventilatory failure in COPD is caused by impaired respiratory mechanics and an imbalance of capacity and load of the respiratory muscles. Continuous positive airway pressure (CPAP), pressure support ventilation (PSV), proportional assist ventilation (PAV) or controlled mechanical ventilation (CMV) are effective in unloading the respiratory pump. CPAP reduces the inspiratory pressure time product by reducing the elastic work of breathing due to intrinsic PEEP (PEEPi). PSV and PAV reduce the work of breathing and additionally improve alveolar ventilation and CO2 elimination. In spontaneous breathing patients these modes of ventilation should be applied non invasively by using a face mask. In CMV, hyperinflation should be avoided by choice of low tidal volumes and long exspiratory times (low respiratory rate, I:E ratio 1:3, 1:4). In the weaning from CMV, PSV or PAV and CPAP is used. There seems to be a beneficial effect in nocturnal intermittent nonivasive ventilation (NPPV) in chronic hypercapnic stable COPD patients with documented hypoventilation during the night, which is reversible by NPPV.
Subject(s)
Pulmonary Disease, Chronic Obstructive/therapy , Respiration, Artificial , Acute Disease , Clinical Trials as Topic , Continuous Positive Airway Pressure , Humans , Positive-Pressure Respiration , Pulmonary Disease, Chronic Obstructive/complications , Pulmonary Disease, Chronic Obstructive/physiopathology , Respiratory Insufficiency/etiology , Respiratory Insufficiency/therapy , Time Factors , Work of BreathingABSTRACT
OBJECTIVE: Prone positioning in patients with adult respiratory distress syndrome is a well-known method to improve oxygenation. The aim of our study was to evaluate a new device for prone positioning, the prone-head support system (PHS system), with regard to reduction of cutaneous pressure sores. METHODS: In a pilot study we randomized 8 patients with ARDS in two groups: 180 degrees standard prone positioning (group without mask) and prone positioning with the PHS system (group with mask). The PHS system consists of a facemask support, which is connected to an adapted air suspension bed. The patients of both groups were intermittently proned for several days. We evaluated the pressure sores on head and neck before turning the patients prone for the first time and after each period of prone positioning. We documented the quantity, the size, the type and the localization of the pressure sores. RESULTS: There was no significant difference in the mean duration of prone positioning (27.1+/-14.7 hours in the group with mask versus 24.5+/-18.7 h in the group without mask). In the group with mask there were 1.5+/-0.8 new pressure sores by each proning, whereas in the group without mask there were 2.37+/-1.6 new pressure sores, which was lower, but not significantly. The overall area of pressure sores (798 mm2 versus 3184 mm2, p=0.004), the area of pressure sores per patient (199.5+/-104.7 mm2 versus 796+/-478 mm2, p=0.03) and the increase of the area of pressure sores per proning (79.8+/-52.0 mm2 versus 398.0+/-214.3 mm2, p=0.004) were significantly lower in the group with mask in comparison to the group without mask. The lips were the most effected localization in both groups. The pressure sores in the group with mask were less severe and showed a homogenous distribution in comparison to the group without mask. Blisters dominated in the group with mask in comparison to erosions, necrosis and ulcers in the group without mask. CONCLUSION: The PHS system with its face mask is able to reduce the extent and the severity of pressure sores in patients ventilated in prone position. Controlled randomized studies with large study populations seem justified.
