Twenty patients (23-76 yr) were studied with regard to lung tissue changes prior and following induction of general anesthesia muscular relaxation, another four subjects for a longer period awake. The transverse thoracic area the structure determined by computerized tomography. No abnormalities in noted before anesthesia. Within 5 min after induction, including all had developed crest-shaped increased density dependent regions both lungs. They largest most caudal segment (4.8 +/- 0.8% area,...

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.Nine healthy adults were studied awake while breathing 1) air, 2) 12% O2 N2, 3) followed by same mixture N2 containing 40 ppm NO. Pulmonary artery radial pressures monitored.The PaO2 decreased from 106 +/- 4 (mean standard error mean) air (21% O2) to 47 2 mmHg after 6 min O2. Concomitantly, mean pressure (PAP)...

Background The use of 100% oxygen during induction anesthesia may produce atelectasis. authors investigated how different concentrations affect the formation atelectasis and fall in arterial saturation apnea. Methods Thirty-six healthy, nonsmoking women were randomized to breathe 100, 80, or 60% for 5 min general anesthesia. Ventilation was then withheld until saturation, assessed by pulse oximetry, decreased 90%. Atelectasis studied with computed tomography. Results a transverse scan near...

Lung densities (atelectasis) and pulmonary gas exchange were studied in 13 supine patients with no apparent lung disease, the former by transverse computerized tomography (CT) latter a multiple inert elimination technique for assessment of distribution ventilation/perfusion ratios. In awake state patient had clear signs atelectasis on CT scan. ventilation perfusion well matched most patients. Three shunts corresponding to 2-5% cardiac output, one there was low poorly ventilated regions....

Background Morbidly obese patients show impaired pulmonary function during anesthesia and paralysis, partly due to formation of atelectasis. This study analyzed the effect general three different ventilatory strategies reduce amount atelectasis improve respiratory function. Methods Thirty (body mass index 45 +/- 4 kg/m) scheduled for gastric bypass surgery were prospectively randomized into groups: (1) positive end-expiratory pressure 10 cm H2O (PEEP), (2) a recruitment maneuver with 55 s...

Functional residual capacity (FRC), rib cage and abdominal dimensions (rc-ab), central blood volume (CBV), extra vascular lung water (EVLW) were measured in six lung-healthy subjects awake during halothane anesthesia, muscle paralysis, mechanical ventilation. FRC was assessed by multiple breath nitrogen washout, rc-ab computerized tomography, CBV EVLW a double-indicator dilution technique (thermo-dye). During decreased 0.5 1 (17%). The cross-sectional chest area reduced 12-20 cm2, causing an...

The ongoing SARS-CoV-2 pandemic is a global public health emergency posing high burden on nations' care systems and economies. Despite the great effort put in development of vaccines specific treatments, no prophylaxis or effective therapeutics are currently available. Nitric oxide (NO) broad-spectrum antimicrobial potent vasodilator that has proved to be reducing SARS-CoV replication hypoxia patients with severe acute respiratory syndrome. Given potential NO as treatment for infection, we...

Background Atelectasis, an important cause of impaired gas exchange during general anesthesia, may be eliminated by a vital capacity maneuver. However, it is not clear whether such maneuver will have sustained effect. The aim this study was to determine the impact composition on reappearance atelectasis and impairment after Methods A consecutive sample 12 adults with healthy lungs who were scheduled for elective surgery studied. Thirty minutes induction anesthesia fentanyl propofol,...

We studied whether nitric oxide (NO), added at 80 ppm to inspired gas, can exert a bronchodilatory effect in humans. Four groups were studied: (1) healthy adult volunteers (n = 6), (2) subjects with hyperreactive airways 6) during provocation inhaled methacholine (MCh), (3) patients bronchial asthma 13), and (4) chronic obstructive pulmonary disease (COPD, n 6). All body plethysmograph, measuring volume-corrected specific airway conductance (SGaw). No patient or volunteer reacted...

We tested whether the continuous monitoring of dynamic compliance could become a useful bedside tool for detecting beginning collapse fully recruited lung.Prospective laboratory animal investigation.Clinical physiology research laboratory, University Uppsala, Sweden.Eight pigs submitted to repeated lung lavages.Lung recruitment maneuver, effect which was confirmed by predefined oxygenation, mechanics, and computed tomography scan criteria, followed positive end-expiratory pressure (PEEP)...

Thirteen patients with healthy hearts and lungs, a mean age of 68 years, who were scheduled for lower abdominal surgery during isoflurane anaesthesia muscular paralysis, investigated arterial blood gases, spirometry, pulmonary x‐ray computed tomography (CT) the chest before anaesthesia, as well first 4 postoperative days. Before lung function gas exchange normal in all patients. Pulmonary CT scans lungs also normal. During 6 13 developed atelectasis (mean 1.0% intrathoracic transverse area...

Objective To evaluate whether the shape of airway pressure-time (Paw-t) curve during constant flow inflation corresponds to radiologic evidence tidal recruitment or hyperinflation in an experimental model acute lung injury. Design Prospective randomized laboratory animal investigation. Setting Department Clinical Physiology, University Uppsala, Sweden. Subjects Anesthetized, paralyzed, and mechanically ventilated pigs. Interventions Acute injury was induced by lavage. During inspiratory...

Pulmonary gas exchange and the development of atelectasis were studied in eight essentially lung-healthy patients, awake during halothane anaesthesia with mechanical ventilation. Gas was evaluated by a multiple inert-gas elimination technique conventional blood-gas analysis, computerized tomography (CT). Ventilation lung perfusion well matched majority patients when awake. In two there low poorly ventilated regions (low VA/Q). One patient had shunt corresponding to 4% cardiac output. None...

Transverse sections of lung tissue were studied in patients by computerized tomography during anaesthesia and the postoperative period. Eight intravenous (thiopentone) six inhalational (halothane) anaesthesia. The latter both spontaneous mechanical ventilation. Five who underwent surgery for inguinal hernia five whom laparotomy was performed 1 h 24 postoperatively. No patient showed any changes while awake preoperatively, all developed dependent, crest‐shaped densities within 5–10 min...

We aimed to describe the frequency of atelectasis occurring during anaesthesia, size and pattern atelectasis, standardise method identifying calculate its area.Patients (n = 109) scheduled for elective abdominal surgery were examined with CT thorax anaesthesia.In 95 patients (87%) dependent pulmonary densities seen, interpreted as atelectasis. Two different types found-homogeneous (78%) non-homogeneous (9%). Attenuation values in histograms lung studied using 2 methods calculating...

Background: General anaesthesia impairs the gas exchange in lungs, and moderate desaturation (SaO 2 86–90%) occurred 50% of anaesthetised patients a blinded pulse oximetry study. A high FiO might reduce risk hypoxaemia, but can also promote atelectasis. We hypothesised that positive end‐expiratory pressure (PEEP) level 10 cmH O prevent atelectasis during ventilation with an =1.0. Methods: Atelectasis was evaluated by computed tomography (CT) 13 ASA I–II undergoing elective surgery. CT scans...

In Brief General anesthesia promotes atelectasis formation, which is augmented by administration of large oxygen concentrations. We studied the efficacy positive end-expiratory pressure (PEEP) application during induction general (fraction inspired [Fio2] 1.0) to prevent atelectasis. Sixteen adult patients were randomly assigned one two groups. Both groups breathed 100% O2 for 5 min and, after a induction, mechanical ventilation via face mask with Fio2 1.0 another before endotracheal...