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A method is presented for determining the pulmonary blood flow from measurements of the time-averaged end-tidal pCO2 and the CO2 output. The novel technique is based on a formula that is derived from Fick's principle in such a way that it allows a direct calculation of the lung perfusion from simultaneously measured changes in end-tidal pCO2 and CO2 output.(More)
Twenty patients (23-76 yr) were studied with regard to lung tissue changes prior to and following induction of general anesthesia with muscular relaxation, and another four subjects were studied for a longer period awake. The transverse thoracic area and the structure of the lung tissue were determined by computerized tomography. No abnormalities in the(More)
Formation of atelectasis is one mechanism of impaired gas exchange during general anaesthesia. We have studied manoeuvres to re-expand such atelectasis in 16 consecutive, anaesthetized adults with healthy lungs. In group 1 (10 patients), the lungs were inflated stepwise to an airway pressure (Paw) of 10, 20, 30 and 40 cm H2O. In group 2 (six patients),(More)
We have studied the effects of anaesthesia on atelectasis formation and gas exchange in 45 patients of both sexes, smokers and nonsmokers, aged 23-69 yr. None of the patients showed clinical signs of pulmonary disease, and preoperative spirometry was normal. In the awake patient, partial pressure of arterial oxygen (PaO2) decreased with increasing age (P(More)
BACKGROUND Nitric oxide (NO), an endothelium-derived relaxing factor, acts as a local vasodilator. The authors examined the effects of NO on pulmonary and systemic circulation in human volunteers. METHODS Nine healthy adults were studied awake while breathing 1) air, 2) 12% O2 in N2, 3) followed by the same mixture of O2 and N2 containing 40 ppm of NO.(More)
OBJECTIVE To evaluate whether the shape of the airway pressure-time (Paw-t) curve during constant flow inflation corresponds to radiologic evidence of tidal recruitment or tidal hyperinflation in an experimental model of acute lung injury. DESIGN Prospective randomized laboratory animal investigation. SETTING Department of Clinical Physiology,(More)
The multiple inert-gas elimination technique (MIGET) is a complex mathematical model and experimental technique for understanding pulmonary gas exchange. Simpler mathematical models have been proposed that have a limited view compared with MIGET but may be applicable for use in clinical practice. This study examined the use of a simple model of gas exchange(More)
Oleic acid (OA) injection, lung lavage, and endotoxin infusion are three commonly used methods to induce experimental lung injury. The dynamics of lung collapse and recruitment in these models have not been studied, although knowledge of this is desirable to establish ventilatory techniques that keep the lungs open. We measured lung density by computed(More)
Objective: To investigate ventilation-perfusion (VA/Q) relationships, during continuous axial rotation and in the supine position, in patients with acute lung injury (ALI) using the multiple inert gas elimination technique. Design: Prospective investigation. Setting: Eighteen-bed intensive care unit in a university hospital. Patients and interventions: Ten(More)
BACKGROUND Recent studies have shown that left ventricular geometric adaptation to hypertension is complex. The spectrum of geometric adaptations in a general population and its relationship to systolic and diastolic function has, however, not been investigated. OBJECTIVES AND METHODS This echocardiographic and Doppler study investigated the relationships(More)