Critical care medicine
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Critical care medicine · Jun 1989
Retracted PublicationInfluence of acute volume loading on right ventricular function after cardiopulmonary bypass.
The influence of acute volume loading on right ventricular function immediately after extracorporeal circulation (ECC) was investigated in 25 patients undergoing elective aortocoronary bypass grafting. In addition to commonly monitored hemodynamic variables, right ventricular (RV) ejection fraction (EF) was measured by thermodilution technique using a new fast-response thermodilution catheter. In eight patients with concomitant severe stenosis (greater than 89%) of the right coronary artery (RCA), volume loading was followed by a decreased RVEF and cardiac output. ⋯ Increased end-diastolic volume and decreased RV contractility index indicated that patients with myocardial ischemia during cardiac surgery procedures sometimes were unable to make the adaptations required. We conclude that cardiocirculatory dysfunction associated with ECC may be caused by depressed RV function. Acute volume loading in this situation may lead to further deterioration of myocardial function due to RV failure, a condition which cannot be diagnosed readily at the bedside with the usual monitoring techniques.
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Critical care medicine · Jun 1989
Case ReportsInverse ratio ventilation in a 6-year-old with severe post-traumatic adult respiratory distress syndrome.
We successfully employed inverse ratio ventilation on a 6-year-old multiple trauma victim with severe adult respiratory distress syndrome after conventional ventilation modes using volume ventilation with high positive peak inspiratory pressure and PEEP had failed to improve oxygenation.
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Critical care medicine · Jun 1989
Mediastinal, left, and right atrial pressure variations with different modes of mechanical and spontaneous ventilation.
Variations in mediastinal, left, and right atrial pressures (MedP, LAP, RAP, respectively) were measured by means of catheters and tubes positioned in ten patients with nonvalvular cardiac surgery. For each pressure, a maximum, minimum, and mean value was determined in relation to its oscillations during the respiratory cycle. Thus, we compared the variations in MedP, LAP, and RAP in controlled mechanical ventilation (CMV), CMV with 5 cm H2O PEEP, synchronous intermittent mandatory ventilation (SIMV), SIMV with 5 cm H2O PEEP, continuous positive airway pressure (CPAP), and spontaneous respiration (SR). ⋯ The experimental model revealed a strong linear relation between the values obtained with air-filled tubes and those obtained with water-filled esophageal balloons (r = .99, p less than .001). These results suggest that the mean values of MedP, LAP, and RAP do not reflect the dynamic variations in ventricular filling pressure accurately, nor the important negative inspiratory peaks that appear in different types of ventilation using spontaneous cycles with and without PEEP. These inspiratory peaks can overload the left ventricle by hydrostatic gradients, and lead to pulmonary edema in susceptible patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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Critical care medicine · Jun 1989
Comparative StudyComparison of a sidestream and mainstream capnometer in infants.
This study was designed to compare capnograms obtained from a sidestream and mainstream capnometer during rapid mechanical ventilation in infants. Ten infants were studied during elective anesthesia and surgery. ⋯ The recordings obtained with the sidestream machine were grossly distorted, with flattening of the ascending limb (slope 37.3 vs. 153.3 torr/sec, sidestream vs. mainstream, p less than .001) and absence of the alveolar plateau. The mainstream analyzer gives a more accurate representation of the expired CO2 waveform in small children at rapid respiratory rates.