Intensive care medicine
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Intensive care medicine · Jan 1989
Reflection of differential pulmonary perfusion in polytrauma patients on differential lung ventilation (DLV). A comparison of two CO2-derived methods.
Seventeen polytrauma patients with asymmetric pulmonary contusion were treated with differential lung ventilation (DLV). The ratios of differential values of end-tidal CO2 concentration (ETCO2) and CO2 excretion ml/min (VCO2) were compared as indirect parameters for differential pulmonary perfusion. Both CO2-derived methods indicated asymmetry after starting DLV suggesting asymmetric pulmonary perfusion as a consequence of contusion. ⋯ In two patients with very severe contusion who underwent bilobectomies a marked difference between the ratios of ETCO2 and VCO2 was observed. It is concluded that differential measurement of CO2-derived variables may be useful in indicating differential perfusion in clinical practice on DLV. In very severe asymmetric contusion ETCO2 ratios may underestimate the differential perfusion ratio.
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Intensive care medicine · Jan 1989
Comparative StudyA randomized comparison of total extracorporeal CO2 removal with conventional mechanical ventilation in experimental hyaline membrane disease.
Apnoeic oxygenation (AO) combined with extracorporeal CO2 removal (ECCO2R), using venovenous perfusion across a membrane area of 0.1 m2 has been shown to be feasible in six healthy anaesthetized rabbits. In a further twelve rabbits, ECCO2R has been randomly compared with conventional mechanical ventilation (CMV) following saline lavage to induce respiratory failure. Blood gases were maintained for up to 6 h within the same range (PaO2 = 8-20 kPa, PaCO2 = 4-6 kPa) in two groups of six by varying airway pressures and the oxygen fraction delivered either to the membrane lung (ECCO2R group) or to the ventilator (CMV group). ⋯ CMV subjects deteriorated and had 80% mortality. Hyaline membranes were absent from ECCO2R subjects and present in all CMV subjects. The response to SI suggests that a lung volume recruitment is maintained during AO for up to 1 h but is ineffective during CMV.
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Intensive care medicine · Jan 1989
Comparative StudyComparison of pressure support ventilation and assist control ventilation in patients with acute respiratory failure.
We compared the effects of pressure support ventilation (PSV) with those of assist control ventilation (ACV) on the breathing pattern, work of breathing and blood gas exchange in 8 patients with acute respiratory failure. During ACV, the tidal volume was set at 10 ml/kg, and the inspiratory flow was set at 50 to 70 l/min. During PSV, the pressure support level selected was 27 +/- 5 cm H2O to make the breathing pattern regular. ⋯ The oxygen cost of breathing, an estimate based on the inspiratory work added by a ventilator and the oxygen consumption, did not change significantly. PaO2 was significantly higher during PSV than during ACV. We conclude that PSV using high levels of pressure support can improve the breathing pattern and oxygenation and fully sustain the patient's ventilation while matching his inspiratory efforts.
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Intensive care medicine · Jan 1989
Maximum expiratory airflow during chest physiotherapy on ventilated patients before and after the application of an abdominal binder.
Chest physiotherapy using a manual ventilation technique was carried out on 9 intubated patients. One patient was studied on two occasions. ⋯ Chest physiotherapy increased the mean MEFR and application of an abdominal binder (together with physiotherapy) caused a further increase in MEFR. The mean MEFR (assuming a common Vt of 1360 ml) in each group was; (A) = 73.3 l min-1, (B) = 103.9 l min-1, (C) = 113.93 l min-1.
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Intensive care medicine · Jan 1989
Case ReportsEffect of positional change on ventilation-perfusion distribution in unilateral pleural effusion.
The effect of pleural effusion on lung function and gas exchange has not been adequately defined. We used the multiple "inert" gas technique to study gas exchange and ventilation-perfusion relationships in both the left and the right lateral decubitus positions in a patient with a moderate unilateral (left) pleural effusion. ⋯ The ventilation-perfusion relationships were also nearly identical for both body positions. We conclude that a pleural effusion of moderate size has little effect on overall gas exchange and ventilation-perfusion relationships and that complex mechanisms of the respiratory system compensate for the effusion.