Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Aug 1983
Selective PEEP in acute bilateral lung disease. Effect on patients in the lateral posture.
Seven patients with acute respiratory failure due to diffuse and fairly uniform lung disease were studied during mechanical ventilation in the lateral decubital position with: (a) zero end-expiratory pressure (ZEEP) through a double-lumen oro-bronchial tube to permit a recording of the ventilation to each lung; (b) bilateral positive end-expiratory pressure (PEEP) of 1.2 kPa, with maintenance of ventilation distribution between lungs as observed during ZEEP; (c) selective PEEP of 1.2 kPa, applied to the dependent lung only, with ventilation as during ZEEP; and (d) conventional PEEP of 1.2 kPa applied to both lungs through a single-lumen tube, with free distribution of ventilation between the lungs. During ZEEP, 69% of ventilation was distributed to the non-dependent and 31% to the dependent lung; cardiac output was 6.51 X min-1, venous admixture (QS/QT) 40% and arterial oxygen tension (PaO2) 8.3 kPa. With bilateral PEEP, functional residual capacity (FRC) increased by 0.331, cardiac output was reduced to 5.11 X min-1 and venous admixture to 32%. ⋯ With selective PEEP the dependent lung FRC increased by 0.211 and the FRC of the non-dependent lung decreased by 0.081. Cardiac output increased to 6.11 X min-1, which was no longer significantly different from that during ZEEP. Venous admixture remained at the same level as with bilateral PEEP.(ABSTRACT TRUNCATED AT 250 WORDS)
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Acta Anaesthesiol Scand · Aug 1983
The anatomical shape of the airway during endotracheal intubation.
The shape of the airway during endotracheal intubation was studied from lateral radiographs of patients lying supine on the operating table, with the neck in the normal, extended and flexed position. A computer programme calculated the anterior contour of the tube and the posterior contour of the airway as mean values of the original contours on the radiographs. The mean configuration of the airway in intubated individuals was then presented in a standard coordinate system. ⋯ Our results also showed that patients were routinely placed on the operating table with the head in an unnecessarily extended position. Such a position may partly obstruct the blood flow in the vertebral arteries. An improvement in operating table design is desirable to facilitate optimal positioning of the patient's head during routine surgery.