BACKGROUND AND OBJECTIVE:Measurement of central blood volumes (CBV), such as global end-diastolic volume (GEDV) and right ventricular end-diastolic volume (RVEDV) are considered appropriate estimates of intravascular volume status. However, to apply those parameters for preload assessment in mechanically ventilated patients, the influence of tidal volume (TV) and positive endexpiratory airway pressure (PEEP) on those parameters must be known. METHODS:In 13 mechanically ventilated piglets, the effect of low (10 mL kg(-1)) and high (20 mL kg(-1)) TVs on CBV was investigated in absence and presence of PEEP (0 and 15 cm H(2)O). GEDV, RVEDV, right heart (RHEDV) and left heart end-diastolic volume (LHEDV) were measured by thermodilution. Blood flow on the descending thoracic aorta measured with an ultrasonic flow-probe served to determine stroke volume (SV). Measurements were performed during baseline conditions, after volume loading with previously extracted haemodilution blood (20 mL kg(-1)) and following haemorrhage (30 mL kg(-1)). RESULTS:Application of PEEP decreased GEDV and SV significantly (P < 0.05). Augmenting TV did not reduce GEDV systematically, but significantly reduced SV (P < 0.05). Changes in ventilator settings only influenced RVEDV following volume loading (P < 0.05). RHEDV and LHEDV decreased following application of PEEP, but only RHEDV decreased after augmenting TV at baseline and following volume loading. Correlation of SV with parameters of CBV was r = 0.487 (P < 0.01) for GEDV, r = 0.553 (P < 0.01) for RVEDV, r = 0.596 (P < 0.01) for RHEDV and r = 0.303 (P < 0.01) for LHEDV. CONCLUSION:Application of PEEP decreases CBV and SV. Augmenting TV reduces SV but not CBV. There is a moderate correlation between parameters of CBV and cardiac performance.

OBJECTIVE:To investigate whether plasma levels of prostacyclin (PGI2) and thromboxane A(2) (TxA2) are a function of the infusion rate of soybean-based fat emulsions, severity of systemic inflammation, and pulmonary organ failure.DESIGN:Prospective, randomized, crossover study.SETTING:Intensive care unit of a university hospital.PATIENTS:Eighteen critically ill patients, ten presenting with severe sepsis, eight with SIRS or sepsis complicated with ARDS.INTERVENTIONS:Patients were randomly assigned to receive rapid fat infusion over 6 h (rFI) or slow fat infusion over 24 h (sFI) along with parenteral nutrition.MEASUREMENTS AND RESULTS:The stable prostanoids 6-keto-PGF1alpha and TxB2 were measured in arterial and mixed venous blood samples, and at 6-h periods trans-pulmonary balances (TPB) were calculated. Free linoleic acid fraction was determined in arterial blood. rFI induced greater increase of linoleic acid than sFI in both groups. Enhanced prostanoid levels and correlations with linoleic acid availabilities were found, however, in ARDS patients only, revealing the highest sepsis- and lung injury scores. Averaged TPB per 24 h was positive in the sepsis group and negative in the ARDS group as rFI induced lowest TPB values for TxB2 at 6 h.CONCLUSION:The quantity of prostanoids formed and their subsequent utilization are dependent on the availability of precursor linoleic acid and are probably affected by the severity of SIRS or sepsis and the existence of pulmonary organ failure, respectively. Because TxA2 might be extracted by the injured lung, rapid infusion of soybean-based fat emulsions should be avoided in patients suffering from severe pulmonary organ failure.

OBJECTIVE:To investigate whether rapid or slowly infused intravenous fat emulsions affect the ratio of prostaglandin I2/thromboxane A2 in arterial blood, pulmonary hemodynamics, and gas exchange. DESIGN:Prospective, controlled, randomized, crossover study. SETTING:Operative intensive care unit of a university hospital. PATIENTS:Eighteen critically ill patients. Ten patients were stratified with severe sepsis, and eight patients had acute respiratory distress syndrome (ARDS). INTERVENTIONS:Patients were assigned randomly to receive intravenous fat emulsions (0.4 x resting energy expenditure) over 6 hrs (rapid fat infusion) or 24 hrs (slow fat infusion) along with a routine parenteral nutrition regimen, by using a crossover study design. MEASUREMENTS AND MAIN RESULTS:Systemic and pulmonary hemodynamics as well as gas exchange measurements were recorded via respective indwelling catheters. Arterial thromboxane B2 and 6-keto-prostaglandin-F1alpha plasma concentrations were obtained by radioimmunoassay, and 6-keto-prostaglandin-F1alpha/thromboxane B2 ratios (P/T ratios) were calculated. Data were collected immediately before and 6, 12, 18, and 24 hrs after onset of fat infusion. In the ARDS group, P/T ratio increased by rapid fat infusion. Concomitantly, pulmonary shunt fraction, alveolar-arterial oxygen tension difference [P(a-a)o2]/Pao2, and cardiac index increased as well, whereas pulmonary vascular resistance and Pao2/Fio2 declined. After slow fat infusion, a decreased P/T ratio was revealed. This was accompanied by decreased pulmonary shunt fraction, lowered P(a-a)o2/Pao2, and increased Pao2/Fio2. Correlations between plasma concentrations of 6-keto-prostaglandin-F1alpha or thromboxane B2 and measures of respiratory performance could be shown during rapid and slow fat infusion, respectively. In the sepsis group, the P/T ratio remained unchanged at either infusion rate, but pulmonary shunt fraction and P(a-a)o2/Pao2 decreased after rapid fat infusion, whereas Pao2/Fio2 increased. CONCLUSION:Pulmonary hemodynamics and gas exchange are related to changes of arterial prostanoid levels in ARDS patients, depending on the rate of fat infusion. In ARDS but not in sepsis patients clear of pulmonary organ failure, a changing balance of prostaglandin I2 and thromboxane A2 may modulate gas exchange, presumably via interference with hypoxic pulmonary vasoconstriction.

OBJECTIVES Health-related quality of life and patient satisfaction have become important end points in cardiac surgery. Post-traumatic stress disorder has been described in patients with life-threatening heart disease. In this study, we investigated the occurrence of post-traumatic stress disorder in a sample of patients after cardiac surgery and compared health-related quality of life and patient satisfaction between patients with and without evidence of post-traumatic stress disorder. METHODS We studied 80 patients serially admitted to the intensive care unit after cardiac surgery (bypass grafting, n = 51; aortic valve replacement, n = 29). Health-related quality of life was assessed with the use of the SF-36 Health Status Questionnaire. Post-traumatic stress disorder was measured with a previously validated instrument (the Post-Traumatic Stress Syndrome 10-Questions Inventory), and 20 different aspects of life satisfaction were quantified on a scale ranging from 0 to 10. For measurements of health-related quality of life and post-traumatic stress disorder, age- and gender-comparable healthy individuals, as well as patients with cardiovascular diseases, served as control groups. RESULTS Patients who had cardiac surgery described high life satisfaction summary scores (156 of a maximum of 200 points) and only small impairments in physical and mental SF-36 summary scores when compared with healthy control groups (median reduction 7.15, P <.05). Patients with evidence of post-traumatic stress disorder (n = 15) reported the lowest SF-36 mental health summary scores when compared with patients without stress disorder (38.3 vs 48.4, P =.004) and rated their life satisfaction lower (121.5 vs 162.0, P =.002). CONCLUSIONS Patients who have had cardiac surgery demonstrate a high life satisfaction with an acceptable degree of physical and mental health-related quality of life. Impairments in psychosocial function and life satisfaction were found in a subgroup of patients with evidence of post-traumatic stress disorder.

The advantages of minimally enteral nutritional support (MEE) during critical illness, compared to total parenteral nutrition, are based on a more physiologic route of application and a more complete supply of substrates. Recent investigations have shown a protective effect of MEE with regard to intestinal barrier integrity and decreased infection-related morbidity. There is also evidence of reduced stress response, optimized substrate utilization, and better formula tolerance. However, MEE is an invasive therapeutic procedure with the potential risk of gastric colonization, aspiration, and feeding tube complications. Its clinical use can further be complicated by reflux, diarrhea, and intestinal impact. To overcome most of these problems, the jejunal route of administration is essential. Practicability and efficacy of MEE are dependent on the preexisting extent of the mucosal trauma (ischemic mucosal damage, mucosal atrophy) and the current degree of intestinal hypoperfusion. When absolute contraindications have been ruled out, MEE should be started at a rate of 5-10 ml/h and has to be adjusted according to clinical feasibility. The use of combined enteral and parenteral nutritional support is mandatory. Total supply of energy and nitrogen should be guided by monitoring of blood urea nitrogen, urea production rate, serum concentrations of triglycerides and glucose. This strategy of nutritional support may precipitate a hypoenergetic nutritional therapy; however, the offered variety of nutrients should be as complete as possible. This, in particular, is of importance as far as the supply of conditionally essential substrates, vitamins and trace elements is concerned. During severe stress metabolism the goal of nutritional support has to focus on the preservation of organ function and yet has to avoid the side effects of hyperalimentation.

European Society of Anaesthesiologists; 8th Annual Meeting with the Austrian International Congress; Vienna, Austria, 1-4 April 2000

We report the case of a 54-year old man with end-stage heart disease in whom the malfunctioning valves of a Novacor LVAS needed to be replaced after 490 days of circulatory support. This procedure could be performed without cardiopulmonary bypass.