The effect of IPPV with and without hyperventilation was studied in five groups of living anaesthetized guineapigs. The respiratory frequency used was in all cases 32 per min and the tidal volume was equal to either 15 per cent of the predicted vital capacity for a period of 15 min or to 75 per cent of the predicted vital capacity for a period of 2 breaths, 5 min, 10 min, or 15 min. Pressure/vo...

Direct tracheoscopy was employed to assess tracheal damage following prolonged intubation. Comparison of conventional and low-pressure cuffs showed that there was less trauma from the low-pressure cuff. Comparison of tube sizes showed a reduction in injury with 8-mm diameter tubes compared with larger ones. Knowledge of tracheal damage following prolonged endotracheal intubation has depended hi...

PURPOSE To assess the hemodynamic changes and bispectral index (BIS) following administration of a continuous rate infusion (CRI) of butorphanol in isoflurane-anesthetized calves. METHODS Eight calves weighing 110 ± 12 kg were included in the study. Anesthesia was induced with 5% isoflurane in O2 delivered via face mask and maintained with end-tidal concentration of 1.4%. IPPV was set to a pe...

Hyperventilation has been a common practice in neuroanesthesia since the 1960’s. However, a review of the literature suggests that hypocapnia was not initially deliberately introduced into practice to improve operating conditions but was perhaps an inadvertent by-product of muscle relaxation and thereby the need for intermittent positive pressure ventilation (IPPV). The first clinical report of...

Deadspace was measured in nine healthy subjects in the supine position, premedicated but awake and breathing spontaneously at a rate of 12 b.p.m. and subsequently under anaesthesia with artificial ventilation with frequencies of 12 and 24 b.p.m. The minute volume was kept at a relatively constant value. The physiological deadspace was calculated using the Bohr equation and the division into ana...

OBJECTIVE Air leak syndromes including pneumothorax, pneumomediastinum and pulmonary interstitial emphysema are frequent in neonatal period. Mechanical ventilation with positive pressure is one of the most common causes of these syndromes. The aim of this study was to evaluate predisposing factors and incidence of pneumothorax in newborns under mechanical ventilation. METHODS This descriptive...

We investigated the mechanism(s) responsible for the decreased cardiac output during continuous positive-pressure ventilation (CPPV). Seven dogs were anesthetized with chloralose-urethane, intubated, and ventilated using a volume ventilator. We measured heart rate, stroke volume, and the determinants of stroke volume: left and right ventricular end-diastolic volumes, isovolumic and ejection pha...

The ventilation of 25 ventilator-dependent traumatic quadriplegic patients was supported by noninvasive means of ventilatory assistance. Twenty-four of the 25 were initially managed by endotracheal intubation, and 23 of these went on to tracheostomy intermittent positive pressure ventilation before being converted to NVA. Seventeen of the 23 patients had their tracheostomies closed. This includ...

Cheyne-Stokes respiration (CSR) is common in patients with congestive heart failure (CHF). This characteristic crescendo-decrescendo pattern of breathing is often seen during sleep in patients with CHF and is a form of central sleep apnoea. Disordered nocturnal breathing leads to oxygen desaturation, poor sleep quality, and altered sleep architecture. These features may lead to complaints of da...