Abstract
Open lung ventilation (OLV) consists of recruitment maneuvers, followed by low tidal volume and elevated positive end-expiratory pressure (PEEP). Elevated PEEP is associated with an increased right ventricular (RV) afterload. We investigated the effect of OLV on RV afterload during inspiration and expiration in patients after cardiac surgery using Doppler echocardiography. In 28 patients scheduled for cardiac surgery, two ventilation strategies were applied in a randomized cross-over design. During OLV, recruitment maneuvers were applied until PaO2/FiO2 > 375 Torr was achieved (reflecting an open lung) and were maintained by the use of sufficient levels of PEEP. The tidal volume was 4–6 ml/kg. During conventional mechanical ventilation (CMV) the ventilation was with a low tidal volume (6–8 ml/kg) with 5 cmH2O PEEP, without recruitment maneuvers. The acceleration time (Acmean) of the pulmonary artery was measured with transesophageal echocardiography in a long-axis view of the pulmonary artery during end-inspiration and end-expiration. The total PEEP in the OLV group was 14 ± 4 compared with 5 ± 1 cmH2O in the CMV group. During expiration, the Acmean of both ventilation strategies was comparable. Inspiration caused a significant decrease of Acmean compared with expiration during CMV (Table (Table1).1). Surprisingly, this did not occur during OLV. Table 1 We conclude that despite the use of 'relatively' high PEEP, OLV with low tidal volume does not increase RV afterload during inspiration and expiration.
Highlights
Tight blood glucose (BG) control has been shown to videos of the alveolar dynamics
Computer-advised insulin infusion in postoperative cardiac surgery patients: a randomized prospective controlled multicenter trial quality the alveoli are observed at an open chest wall under a glass plate representing an artificial situation. To circumvent this restriction we developed a method of intravital endoscopy and tested it on an animal rat model
1Royal Brompton Hospital, London, UK; 2Medical University Graz, observation from mechanical deformation due to the tip of the Austria; 3Charles University Hospital, Prague, Czech Republic; endoscope we developed a flushing catheter that continuously
Summary
Tight blood glucose (BG) control has been shown to videos of the alveolar dynamics. The thorax remains intact.decrease morbidity and mortality in critically ill patients [1] but is Results Figure 1 shows a tissue area after lavage of 0.8 mm difficult to achieve using standard insulin infusion protocols. Results Patient characteristics (mean ± SD): age 57.4 ± 15.4 years, 28 female, 52 male, APACHE II score 28.2 ± 6.6; number of organ failures 4.0 ± 1.12; preceding ICU period 8.5 ± 9.3 days; continuous sedation with midazolam 31.2 ± 34.2 mg/hour, fentanyl 0.12 ± 0.08 mg/hour, propofol 45.6 ± 105.2 mg/hour; sedation assessment according to RS 5.65 ± 0.63, CPS 5.15 ± 1.67, CKS 0.65 ± 0.69, CS 9.34 ± 2.13 und LSS 1.78 ± 1.69, RASS –4.50 ± 1.27, FiO2 0.52 ± 0.17, PEEP 8.2 ± 2.4 cmH2O, ventilatory frequency 20.5 ± 4.8/min, pressure control 16.8 ± 4.4 cmH2O, tidal volume 540 ± 115 ml, TVV 2525.6 ± 11,366 ml (minimum 1.52; maximum 91,586). We hypothesized that S100β levels correlate with this tumor’s preoperative characteristics and with perioperative neurological injury despite its supratentorial location and non-neural origin
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