Search

Introduction Atelectasis is a common finding in acute lung injury, leading to increased shunt and hypoxemia. Current treatment strategies aim to recruit alveoli for gas exchange. Improvement in oxygenation is commonly used to detect recruitment, although the assumption that gas exchange parameters adequately represent the mechanical process of alveolar opening has not been proven so far. The aim of this study was to investigate whether commonly used measures of lung mechanics better detect lung tissue collapse and changes in lung aeration after a recruitment maneuver as compared to measures of gas exchange Methods In eight anesthetized and mechanically ventilated pigs, acute lung injury was induced by saline lavage and a recruitment maneuver was performed by inflating the lungs three times with a pressure of 45 cmH2O for 40 s with a constant positive end-expiratory pressure of 10 cmH2O. The association of gas exchange and lung mechanics parameters with the amount and the changes in aerated and nonaerated lung volumes induced by this specific recruitment maneuver was investigated by multi slice CT scan analysis of the whole lung. Results Nonaerated lung correlated with shunt fraction (r = 0.68) and respiratory system compliance (r = 0.59). The arterial partial oxygen pressure (PaO2) and the respiratory system compliance correlated with poorly aerated lung volume (r = 0.57 and 0.72, respectively). The recruitment maneuver caused a decrease in nonaerated lung volume, an increase in normally and poorly aerated lung, but no change in the distribution of a tidal breath to differently aerated lung volumes. The fractional changes in PaO2, arterial partial carbon dioxide pressure (PaCO2) and venous admixture after the recruitment maneuver did not correlate with the changes in lung volumes. Alveolar recruitment correlated only with changes in the plateau pressure (r = 0.89), respiratory system compliance (r = 0.82) and parameters obtained from the pressure-volume curve. Conclusion A recruitment maneuver by repeatedly hyperinflating the lungs led to an increase of poorly aerated and a decrease of nonaerated lung mainly. Changes in aerated and nonaerated lung volumes were adequately represented by respiratory compliance but not by changes in oxygenation or shunt.

Increasing age and co-morbidities of patients admitted for surgery impose new challenges on the anesthesiologist.Review of current literature regarding the perioperative management of patients with chronic pulmonary disease.If patients are treated adequately, surgery can be safely performed under regional and general anaesthesia. Major risk factors include type of surgery, type and duration of anesthesia, general health status and smoking history, but not certain lung function parameters. Regional anesthesia remains the first choice for intra- and postoperative care, and if general anesthesia is necessary, early extubation should be achieved. Non-invasive ventilation could be a possible alternative in weaning failure.Assessing the functional status of patients admitted to surgery remains a difficult task, and in patients identified at risk by clinical examination additional spirometry and blood gases may be helpful. If there are signs of respiratory failure, the anaesthetist should monitor the patient closely and invasively, yet there is no reason to deny any patient a substantially beneficial operation.

Little is known about the prognosis and outcome of critically ill patients with a prolonged length of stay (LOS). The aim of this study was to examine mortality and its risk factors in patients requiring intensive care therapy for more than 30 days.A retrospective, single-center analysis of data collected in a surgical intensive care unit (ICU) of a university hospital in Germany from 2005 to 2007 was conducted. All demographic data and clinical variables were collected. A univariate analysis followed by multivariate regression was performed to detect the relevant risk factors for short and long-term mortality.Altogether, 10 737 patients were admitted to the ICU; 136 patients fulfilled the criteria for long-term treatment, 75% (N=102) of whom were discharged from ICU. The one-year survival rate was 61.8% (N=60). The most significant risk factors were pulmonary compromise with prolonged mechanical ventilation and infectious disorders leading to sepsis. However, sepsis was not a predictor of outcome. Weaning failure was present in 67.6% (N=92) at day 30 but was reduced to 37.5% of the cases (N=51) over the total course of the stay. Acute and long-term prognoses were determined by a successful weaning.Although the long-term treatment of critically ill patients requires significant effort, the outcome for this particular cohort was reasonably favorable. Prolonged mechanical ventilation and weaning are the factors that influence mortality independently of sepsis. Because reasonable improvements can be shown even after a prolonged LOS, further attention should be paid to weaning processes.