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High Positive End-expiratory Pressure (high + positive_end-expiratory_pressure)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Hepatic effects of an open lung strategy and cardiac output restoration in an experimental lung injury

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2010
M. KREDEL
Background: Ventilation with high positive end-expiratory pressure (PEEP) can lead to liver dysfunction. We hypothesized that an open lung concept (OLC) using high PEEP impairs liver function and integrity dependent on the stabilization of cardiac output. Methods: Juvenile female Pietrain pigs instrumented with flow probes around the common hepatic artery and portal vein, pulmonary and hepatic vein catheters underwent a lavage-induced lung injury. Ventilation was continued with a conventional approach (CON) using pre-defined combinations of PEEP and inspiratory oxygen fraction or with an OLC using PEEP set above the lower inflection point of the lung. Volume replacement with colloids was guided to maintain cardiac output in the CON(V+) and OLC(V+) groups or acceptable blood pressure and heart rate in the OLC(V,) group. Indocyanine green plasma disappearance rate (ICG-PDR), blood gases, liver-specific serum enzymes, bilirubin, hyaluronic acid and lactate were tested. Finally, liver tissue was examined for neutrophil accumulation, TUNEL staining, caspase-3 activity and heat shock protein 70 mRNA expression. Results: Hepatic venous oxygen saturation was reduced to 18 ± 16% in the OLC(V,) group, while portal venous blood flow decreased by 45%. ICG-PDR was not reduced and serum enzymes, bilirubin and lactate were not elevated. Liver cell apoptosis was negligible. Liver sinusoids in the OLC(V+) and OLC(V,) groups showed about two- and fourfold more granulocytes than the CON(V+) group. Heat shock protein 70 tended to be higher in the OLC(V,) group. Conclusions: Open lung ventilation elicited neutrophil infiltration, but no liver dysfunction even without the stabilization of cardiac output. [source]

Diagnosing acute lung injury in the critically ill: a national survey among critical care physicians

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 10 2009
A. P. J. VLAAR
Background: Incidence reports on acute lung injury (ALI) vary widely. An insight into the diagnostic preferences of critical care physicians when diagnosing ALI may improve identification of the ALI patient population. Methods: Critical care physicians in the Netherlands were surveyed using vignettes involving hypothetical patients and a questionnaire. The vignettes varied in seven diagnostic determinants based on the North American European Consensus Conference and the lung injury score. Preferences were analyzed using a mixed-effects logistic regression model and presented as an odds ratio (OR) with a 95% confidence interval. Results: From 243 surveys sent to 30 hospitals, 101 were returned (42%). ORs were as follows: chest X-ray consistent with ALI: OR 1.7 (1.3,2.3), high positive end-expiratory pressure (PEEP) (15 cmH2O): OR 5.0 (3.9,6.6), low pulmonary artery occlusion pressures (PAOP) (<18 mmHg): OR 4.7 (3.6,6.1), low compliance (30 ml/cmH2O): OR 0.7 (0.5,0.9), low PaO2/FiO2 (<250 mmHg): OR 9.2 (6.9,12.3), absence of heart failure: OR 1.2 (0.9,1.5), presence of a risk factor for ALI (sepsis): OR 1.0 (0.8,1.3). The questionnaire revealed that critical care physicians with an anesthesiology background differed from physicians with an internal medicine background with regard to hemodynamic variables when considering an ALI diagnosis (P<0.05). Conclusions: Dutch critical care physicians consider the PEEP level, but not the presence of a risk factor for ALI, as an important factor to diagnose ALI. Background specialty of critical care physicians influences diagnostic preferences and may account for variance in the reported incidence of ALI. [source]

Beneficial effects of high positive end-expiratory pressure in lung respiratory mechanics during laparoscopic surgery

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2009
L. F. MARACAJÁ-NETO
Background: The effect of neuromuscular blockade (NMB) and positive end-expiratory pressure (PEEP) on the elastic properties of the respiratory system during pneumoperitoneum (PnP) remains a controversial subject. The main objective of the present study was to evaluate the effects of NMB and PEEP on respiratory mechanics. Methods: We performed a dynamic analysis of respiratory mechanics in patients subjected to PnP. Twenty-one patients underwent cholecystectomy videolaparoscopy and total intravenous anesthesia. The respiratory system resistance (RRS), pulmonary elastance (EP), chest wall elastance (ECW), and respiratory system elastance (ERS) were computed via the least squares fit technique using an equation describing the motion of the respiratory system, which uses primary signs such as airway pressure, tidal volume, air flow, and esophageal pressures. Measurements were taken after tracheal intubation, PnP, NMB, establishment of PEEP (10 cmH2O), and PEEP withdrawal [zero end-expiratory pressure (ZEEP)]. Results: PnP significantly increased ERS by 27%; both EP and ECW increased 21.3 and 64.1%, respectively (P<0.001). NMB did not alter the respiratory mechanic properties. Setting PEEP reduced ERS by 8.6% (P<0.05), with a reduction of 10.9% in EP (P<0.01) and a significant decline of 15.7% in RRS (P<0.05). These transitory changes in elastance disappeared after ZEEP. Conclusions: We concluded that the 10 cmH2O of PEEP attenuates the effects of PnP in respiratory mechanics, lowering RRS, EP, and ERS. These effects may be useful in the ventilatory approach for patients experiencing a non-physiological increase in IAP owing to PnP in laparoscopic procedures. [source]

Pumpless extracorporeal removal of carbon dioxide combined with ventilation using low tidal volume and high positive end-expiratory pressure in a patient with severe acute respiratory distress syndrome

ANAESTHESIA, Issue 2 2009
T. Bein
Summary The effects of the combination of a ,lowest' lung ventilation with extracorporeal elimination of carbon dioxide by interventional lung assist are described in a patient presenting with severe acute respiratory distress syndrome due to fulminant pneumonia. Reducing tidal volume to 3 ml.kg,1 together with interventional lung assist resulted in a decrease in severe hypercapnia without alveolar collapse or hypoxaemia but with a decrease in serum levels of interleukin-6. This approach was applied for 12 days with recovery of the patient, without complications. Extracorporeal removal of carbon dioxide by interventional lung assist may be a useful tool to enable ,ultraprotective' ventilation in severe acute respiratory distress syndrome. [source]