Activated platelet aggregation is transiently impaired also by a reduced dose of protamine.

Objectives: Protamine reduces platelet aggregation after cardiopulmonary bypass (CPB). We studied the inhibitory effect of a reduced protamine dose, the duration of impaired platelet function and the possible correlation to postoperative bleeding. Design: Platelet function was assessed by impedance aggregometry in 30 patients undergoing cardiac surgery with CPB at baseline, before protamine administration, after 70% and 100% of the calculated protamine dose, after 20 minutes and at arrival to the intensive care unit. Adenosine diphosphate (ADP), thrombin receptor activating peptide-6 (TRAP), arachidonic acid (AA) and collagen (COL) were used as activators. Blood loss was measured during operation and three hours after surgery. Results are presented as median (25th-75th percentile). Results: Platelet aggregation decreased markedly after the initial dose of protamine (70%) with all activators; ADP 89 (71-110) to 54 (35-78), TRAP 143 (116-167) to 109 (77-136), both p < .01; AA 25 (16-49) to 17 (12-24) and COL 92 (47-103) to 60 (38-81) U, both p < .05. No further decrease was seen after 100% protamine. The effect was transient and after twenty minutes platelet aggregation had started to recover; ADP 76 (54-106), TRAP 138 (95-158), AA 20 (10-35), COL 70 (51-93) U. Blood loss during operation correlated to aggregometry measured at baseline and after protaminization. Conclusions: Protamine after CPB induces a marked decrease in platelet aggregation already at a protamine-heparin ratio of 0.7:1. The impairment seems to be transient and recovery had started after 20 minutes.

EuroSCORE II and N-terminal pro-B-type natriuretic peptide for risk evaluation: an observational longitudinal study in patients undergoing coronary artery bypass graft surgery.

BACKGROUND: Postoperative heart failure remains the major cause of death after cardiac surgery. As N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a predictor for postoperative heart failure, the aim was to evaluate if preoperative NT-proBNP could provide additional prognostic information to the recently launched EuroSCORE II. METHODS: A total of 365 patients with acute coronary syndrome (ACS) undergoing isolated coronary artery bypass graft (CABG) surgery were studied prospectively. Preoperative NT-proBNP and EuroSCORE II were evaluated with regard to severe circulatory failure after operation according to prespecified criteria. To assess what clinical outcomes are indicated by NT-proBNP levels in different risk categories, the patients were stratified according to EuroSCORE II. Based on receiver operating characteristics analysis, these cohorts were assessed with regard to preoperative NT-proBNP below or above 1028 ng litre(-1). The follow-up time averaged 4.4 (0.7) yr. RESULTS: Preoperative NT-proBNP≥1028 ng litre(-1) [odds ratio (OR) 9.9, 95% confidence interval (CI) 1.01-98.9; P=0.049] and EuroSCORE II (OR 1.24, 95% CI 1.06-1.46; P=0.008) independently predicted severe circulatory failure after operation. In intermediate-risk patients (EuroSCORE II 2.0-10.0), NT-proBNP≥1028 ng litre(-1) was associated with a higher incidence of severe circulatory failure (6.6% vs 0%; P=0.007), renal failure (14.8% vs 5.4%; P=0.03), stroke (6.6% vs 0.7%; P=0.03), longer intensive care unit stay [37 (35) vs 27 (38) h; P=0.002], and worse long-term survival. CONCLUSIONS: Combining EuroSCORE II and preoperative NT-proBNP appears to improve risk prediction with regard to severe circulatory failure after isolated CABG for ACS. NT-proBNP may be particularly useful in patients at intermediate risk according to EuroSCORE II. CLINICAL TRIAL REGISTRATION: NCT00489827.

Cost analysis of re-exploration for bleeding after coronary artery bypass graft surgery.

BACKGROUND: Re-exploration for bleeding after cardiac surgery is an indicator of substantial haemorrhage and is associated with increased hospital resource utilization. This study aimed to analyse the costs of re-exploration and estimate the costs of haemostatic prophylaxis. METHODS: A total of 4232 patients underwent isolated, first-time, coronary artery bypass graft (CABG) surgery during 2005-8. Each patient re-explored for bleeding (n=127) was matched with two controls not requiring re-exploration (n=254). Cost analysis was based on resource utilization from completion of CABG until discharge. A mean cost per patient for re-exploration was calculated. Based on this, the net cost of prophylactic treatment with haemostatic drugs for preventing re-exploration was calculated. RESULTS: Patients undergoing re-exploration had higher exposure to clopidogrel before operation, prolonged stays in the intensive care unit, and more blood transfusions than controls. The mean incremental cost for re-exploration was €6290 [95% confidence interval (CI) €3408-€9173] per patient, of which 48% [€3001 (95% CI €249-€2147)] was due to prolonged stay, 31% [€1928 (95% CI €1710-€2147)] to the cost of surgery/anaesthesia, 20% [€1261 (95% CI €1145-€1378)] to the increased number of blood transfusions, and <2% [€100 (95% CI €39-€161)] to the cost of haemostatic drugs. A cost model, at an estimated 50% efficacy for recombinant activated clotting factor VIIa and a 50% expected risk for re-exploration without prophylaxis, demonstrated that to be cost neutral, prophylaxis of four patients needed to result in one avoided re-exploration. CONCLUSIONS: The resource utilization costs were substantially higher in patients requiring re-exploration for bleeding. From a strict cost-effectiveness perspective, clinical interventions to prevent haemorrhage might be underutilized.

Mixed venous oxygen saturation predicts short- and long-term outcome after coronary artery bypass grafting surgery: a retrospective cohort analysis.

BACKGROUND: Complications of an inadequate haemodynamic state are a leading cause of morbidity and mortality after cardiac surgery. Unfortunately, commonly used methods to assess haemodynamic status are not well documented with respect to outcome. The aim of this study was to investigate Sv(O2) as a prognostic marker for short- and long-term outcome in a large unselected coronary artery bypass grafting (CABG) cohort and in subgroups with or without treatment for intraoperative heart failure. METHODS: Two thousand seven hundred and fifty-five consecutive CABG patients and subgroups comprising 344 patients with and 2411 patients without intraoperative heart failure, respectively, were investigated. Sv(O2) was routinely measured on admission to the intensive care unit (ICU). The mean (sd) follow-up was 10.2 (1.5) yr. RESULTS: The best cut-off for 30 day mortality related to heart failure based on receiver-operating characteristic analysis was Sv(O2) 60.1%. Patients with Sv(O2) <60% had higher 30 day mortality (5.4% vs 1.0%; P<0.0001) and lower 5 yr survival (81.4% vs 90.5%; P<0.0001). The incidences of perioperative myocardial infarction, renal failure, and stroke were also significantly higher, leading to a longer ICU stay. Similar prognostic information was obtained in the subgroups that were admitted to ICU with or without treatment for intraoperative heart failure. In patients admitted to ICU without treatment for intraoperative heart failure and Sv(O2) ≥60%, 30 day mortality was 0.5% and 5 yr survival 92.1%. CONCLUSIONS: Sv(O2) <60% on admission to ICU was related to worse short- and long-term outcome after CABG, regardless of whether the patients were admitted to ICU with or without treatment for intraoperative heart failure.

Mixed venous oxygen saturation is a prognostic marker after surgery for aortic stenosis.

BACKGROUND: Adequate monitoring of the hemodynamic state is essential after cardiac surgery and is vital for medical decision making, particularly concerning hemodynamic management. Unfortunately, commonly used methods to assess the hemodynamic state are not well documented with regard to outcome. Mixed venous oxygen saturation (SvO(2)) was therefore investigated after cardiac surgery. METHODS: Detailed data regarding mortality were available on all patients undergoing aortic valve replacement for isolated aortic stenosis during a 5-year period in the southeast region of Sweden (n=396). SvO(2) was routinely measured on admission to the intensive care unit (ICU) and registered in a database. A receiver operating characteristics (ROC) analysis of SvO(2) in relation to post-operative mortality related to cardiac failure and all-cause mortality within 30 days was performed. RESULTS: The area under the curve (AUC) was 0.97 (95% CI 0.96-1.00) for mortality related to cardiac failure (P=0.001) and 0.76 (95% CI 0.53-0.99) for all-cause mortality (P=0.011). The best cutoff for mortality related to cardiac failure was SvO(2) 53.7%, with a sensitivity of 1.00 and a specificity of 0.94. The negative predictive value was 100%. The best cutoff for all-cause mortality was SvO(2) 58.1%, with a sensitivity of 0.75 and a specificity of 0.84. The negative predictive value was 99.4%. Post-operative morbidity was also markedly increased in patients with a low SvO(2). CONCLUSION: SvO(2), on admission to the ICU after surgery for aortic stenosis, demonstrated excellent sensitivity and specificity for post-operative mortality related to cardiac failure and a fairly good AUC for all-cause mortality, with an excellent negative predictive value.

Myocardial metabolism before and after valve replacement for aortic stenosis.

AIM: Post ischemic disturbances of myocardial metabolism that may contribute to postoperative heart failure and are accessible to metabolic treatment have been identified early after coronary surgery. Knowledge derived from these studies may not be applicable to other patient groups. Therefore we studied myocardial energy metabolism in patients operated for isolated aortic stenosis. METHODS: Twenty patients undergoing isolated aortic valve replacement (AVR) because of aortic stenosis without significant regurgitation were studied before and immediately after surgery. Myocardial uptake of oxygen and energy substrates was assessed with coronary sinus catheter technique. RESULTS: Free fatty acids (FFA) were the main source of myocardial energy before and after AVR. A significant uptake of lactate was only recorded preoperatively. A significant uptake of glutamate of the same magnitude as previously described in coronary patients was found pre- and postoperatively. Postoperatively a relative decrease of myocardial oxygen extraction ratio (P<0.001) and oxygen consumption (P=0.14) by approximately 20% was observed. CONCLUSION: Preoperative and postoperative metabolic adaptation with substantial uptake of glutamate, previously claimed to be due to chronic or repetitive ischemia, was demonstrated. The results indicate that oxidative metabolism had not fully recovered when the procedure was completed. However, the potentially unfavorable postoperative metabolic state with predominant reliance on FFA as energy source was out-balanced by the unloading effect of AVR with a reduction in myocardial oxygen extraction.

Assessment of myocardial perfusion in the empty beating porcine heart with laser Doppler flowmetry.

Laser Doppler flowmetry was applied to the empty beating heart of six pigs. Cardiopulmonary bypass was instituted and the preparation allowed continuous and simultaneous measurement of coronary sinus blood flow and local tissue perfusion. An epicardial and an intramuscular probe were used. Significant linear correlation coefficients were obtained between changes of laser Doppler signal and coronary sinus blood flow changes in all seven experiments in four animals (r from 0.71 to 0.94, p less than 0.005) and between laser Doppler signal and changes of extracorporeal bypass in five out of six experiments in four animals (r from 0.82 to 0.99, p less than 0.001). The correlation between coronary sinus flow and bypass flow of four pigs was significant (r from 0.81 to 0.98, p less than 0.001), the coronary flow being about 10% of bypass flow. Muscular activity of the heart contributed to the laser Doppler signal, the magnitude of this "noise level" varying between different experiments even in the same animal. A key question for the applicability of laser Doppler flowmetry to the beating heart is whether it will become possible to discriminate between flow and muscular contribution to the laser Doppler output.

Myocardial uptake of amino acids and other substrates in relation to myocardial oxygen consumption four hours after cardiac operations.

Myocardial metabolism seems to be markedly abnormal during the first hours of reperfusion after aortic crossclamping. Thus we previously demonstrated no uptake of carbohydrate or lipid substrates 1 hour after coronary operations. Amino acids were the only exogenous substrates taken up by the heart. The aim of the present study was to examine if this metabolic abnormality persisted a few hours later. This was done by measuring coronary sinus blood flow and arterial-coronary sinus differences of oxygen, glucose, free fatty acids, glycerol, lactate, beta-OH-butyrate, and amino acids in a similar group of 19 patients 4 to 5 hours after coronary operations. The results demonstrate a change toward normalization of myocardial free fatty acid use, although the threshold for free fatty acid uptake seemed elevated in comparison with that in the normal postabsorptive state. No correlation was found between free fatty acid uptake and myocardial oxygen consumption. Despite elevated arterial levels of glucose, lactate, pyruvate, and beta-OH-butyrate, no uptake was observed. Myocardial amino acid exchange demonstrated a pattern suggestive of postischemic metabolic adaptation. Several amino acids were extracted, glutamate and branched chain amino acids being the quantitatively most important. The uptake of glutamate and branched chain amino acids correlated with myocardial oxygen consumption, which suggests a direct link to myocardial energy metabolism. Myocardial glutamate uptake seemed to be limited by substrate availability.

Effects of insulin on myocardial uptake of branched chain amino acids soon after cardiac operations.

Infusion of insulin-glucose-potassium is used to support the failing heart after cardiac operations. Although the effects on myocardial uptake of carbohydrates and lipids have been described, the effects on myocardial extraction of amino acids are unknown. This study was undertaken to clarify the effect of insulin-glucose-potassium on the pattern of amino acid uptake/release in myocardial and skeletal muscle after coronary operations. The amino acid uptake/release of the heart and of the leg was studied in 18 patients 1 hour after coronary bypass operations. The patients were randomized to treatment with 25 U of fast-acting insulin as a bolus injection followed by a continuous infusion of 1 U/kg body weight for 1 hour, or to serve as control patients. The hyperinsulinemic "clamp" technique was used to keep blood glucose unchanged during the study. In the insulin-treated group, the arterial concentration of 17 of 22 individual amino acids, including the three branched chain amino acids, decreased, the remainder being unchanged. The amino acid uptake/release of the leg was unchanged. The net myocardial uptake of leucine and isoleucine shifted to a no-uptake/no-release in the insulin-treated group, whereas the no-uptake/no-release of tyrosine and phenylalanine turned into a significant release. A positive correlation was observed between arterial concentration and myocardial uptake/release of the three branched chain amino acids. It is suggested that insulin, by lowering the arterial concentration of leucine and isoleucine, inhibited the myocardial uptake of these amino acids. This may have a negative effect on postoperative myocardial protein balance suggested by the release of tyrosine and phenylalanine.

Metabolic and hemodynamic effects of intravenous glutamate infusion early after coronary operations.

Amino acids, particularly glutamate, have been proposed to play an important role in the recovery of cardiac oxidative metabolism after ischemia. In this investigation, the metabolic and hemodynamic effects of glutamate infusion after coronary operations were studied. From 220 to 240 ml 0.1 mol/L l-glutamic acid solution was infused in 10 patients during 1 hour starting 2 hours after operation. A control group of 10 patients received an infusion of 240 ml saline solution. During glutamate infusion, there were significant increases in the uptake of glutamate (from 0.7 +/- 0.2 micromol/min in the basal state to a peak of 5.7 +/- 1.2 micromol/min at 20 minutes) and lactate (from 4.9 +/- 2.0 micromol/min in the basal state to 14.1 +/- 4.4 micromol/min at 60 minutes; p < 0.01), whereas the uptake and release of other substrates remained essentially unaffected. Arterial glutamate levels (in whole blood) increased from 103 +/- 10 micromol/L to 394 +/- 20 micromol/L at 60 minutes. Thirty minutes after discontinuation of the glutamate infusion, arterial levels had decreased to 129 +/- 17 micromol/L. The markedly improved utilization of lactate and the unchanged release of alanine together suggest that the oxidative metabolism of the heart was stimulated by glutamate. The metabolic changes were associated with improved myocardial performance. Left ventricular stroke work index increased from 26.8 +/- 2.1 gm x beat(-1) x m(-2) body surface area to 31.3 +/- 3.1 gm x beat(-1) x m(-2) body surface area during glutamate infusion. Metabolic support with amino acids may provide a means to improve recovery of metabolic and hemodynamic function of the heart early after cardiac operations.

Trauma metabolism and the heart. Uptake of substrates and effects of insulin early after cardiac operations.

In a controlled, randomized study the myocardial uptake/release of individual free fatty acids, glucose, lactate, pyruvate, alanine, and glycerol was studied 1 hour after completion of coronary operations. The effects of insulin were evaluated by means of a hyperinsulinemic "clamp" technique. No significant uptake of free fatty acids was found despite markedly elevated arterial concentrations (mean +/- standard error of the mean, 2.01 +/- 0.19 mmol.L-1), oleic acid, together with palmitic and linoleic acid, constituting 80% of the total plasma free fatty acid level. Insulin treatment (1 unit.kg bw-1.hr-1) prevented a further increase of the plasma free fatty acid level, observed concomitantly in the control group. Insulin affected all individual free fatty acids similarly. Changes in plasma free fatty acid levels occurring during the study and the corresponding myocardial uptake correlated (rS = 0.50 to 0.81). No significant uptake or release of glucose, lactate pyruvate, and glycerol occurred, whereas a myocardial release of alanine was seen. The heart and the concomitant leg uptake/release of glucose (rS = 0.40, p less than 0.05) and lactate (rS = 0.67, p less than 0.01) correlated. A substantial uptake of glucose was achieved and a more positive myocardial balance was obtained for alanine, lactate, and pyruvate with insulin. The changes in heart and the concomitant leg uptake/release correlated (glucose, rS = 0.62, p less than 0.01; lactate, rS = 0.64, p less than 0.01; pyruvate, rS = 0.71, p less than 0.01). It is concluded that the myocardial uptake of substrates during the first hours after coronary surgery is markedly abnormal with no uptake of free fatty acids or carbohydrates. These changes can be explained to some extent by the insulin resistance of trauma metabolism and can be modified by insulin treatment.

Postoperative myocardial ischemia caused by chest tube compression of vein graft.

Here we report an unexpected and possibly overlooked cause of postoperative myocardial ischemia: a chest tube compressing a vein graft. After the position of the chest tube was adjusted, graft flow was reestablished, right ventricular contractility returned, and myocardial infarction was probably prevented. The literature on chest tube complications is briefly reviewed and experience from our institution is reported.

Physiologic aspects in postoperative cardiac patients.

After a cardiac operation, there is reversible myocardial dysfunction that also involves a metabolic disorder. In patients with cardiac failure, care must be taken to reduce the strain on the heart by minimizing systemic oxygen uptake, which is, in fact, the main determinant of cardiac output. Inotropic support may improve cardiac output and tissue oxygenation in cardiac failure, but it also increases myocardial stress directly by increasing myocardial demands and indirectly by increasing systemic energy demands. Mixed venous oxygen saturation reflects the balance between cardiac output and systemic oxygen consumption and indicates whether cardiac output can adequately provide the peripheral tissues with oxygen. This physiologic view toward the treatment of postoperative cardiac failure helps us avoid overtreatment, that is, stimulating cardiac output more than necessary for adequate tissue oxygenation. In this way, the strain on the heart can be reduced and myocardial recovery, enhanced.

Rationale for metabolic support with amino acids and glucose-insulin-potassium (GIK) in cardiac surgery.

Myocardial metabolism and the current state of metabolic intervention under conditions relevant to cardiac surgery are reviewed. The rationale for metabolic support differs considerably in various settings of cardiac surgery. Although preventive measures are theoretically attractive, their use in the preoperative setting remains to be clarified. Amino acid enrichment of blood cardioplegia seems to be justified by an abundance of animal experimental data. In the postoperative setting of cardiac surgery, metabolic abnormalities may explain reversible myocardial dysfunction. Further, the combined effects of ischemia and the systemic neuroendocrine response to surgical trauma may adversely affect recovery. Amino acids, particularly glutamate, seem vital for metabolic recovery in this setting. Treating the relative shortage of glutamate occurring during this period by the administration of exogenous glutamate and counteracting the effects of the systemic neuroendocrine stress response by high-dose glucose-insulin-potassium are measures that have been shown to improve the metabolic state of the heart and subsequently myocardial performance.

Addition of a thiazide: an effective remedy for furosemide resistance after cardiac operations.

BACKGROUND: The frequent use of diuretic drugs in cardiac surgical practice contrasts with the lack of documentation regarding diuretic treatment in this setting. The aims of this study were to delineate the need for diuretic drugs in adult cardiac surgical practice and to evaluate the impact of adding a combination of 50 mg hydrochlorothiazide and 5 mg amiloride orally to patients responding poorly to furosemide. METHODS: Two hundred ten consecutive patients, 159 undergoing coronary artery bypass grafting procedures and 51 having valve operations, were studied. RESULTS: Seventy-seven patients received large doses of furosemide (> or = 80 mg/24 h) at some time during the postoperative course, and of these 20 responded poorly to furosemide (weight loss 0.3 +/- 0.2 kg) despite considerable fluid retention. The addition of hydrochlorothiazide and amiloride provided a prompt and effective remedy to relative furosemide resistance. Average weight loss was 2.3 +/- 0.2 kg (p < 0.01 compared with response to furosemide) and average diuresis was 2,949 +/- 156 mL in the following 24 hours. CONCLUSIONS: Relative furosemide resistance is common after cardiac operations. Thiazides, although they are mild diuretic agents, may serve as useful adjuncts in this setting.

Glutamate and high-dose glucose-insulin-potassium (GIK) in the treatment of severe cardiac failure after cardiac operations.

Postischemic derangement of myocardial metabolism that is further aggravated by the systemic neuroendocrine response to surgical trauma may explain reversible myocardial dysfunction after cardiac surgical procedures. Since 1991, all patients with signs of cardiac failure after operation for ischemic heart disease (45/515 patients) were treated according to our metabolic strategy. Sixteen patients in whom we previously would have considered use of an intraaortic balloon pump were treated by prolonged unloading of the heart with cardiopulmonary bypass, by glutamate infusion, and by high-dose glucose-insulin-potassium. Rapid improvement in hemodynamic performance was seen in the first hour and almost full recovery within 6 hours in the surviving patients (12/16). None of the 3 patients requiring mechanical assist survived. Our early clinical experience suggests that metabolic support with glutamate and high-dose glucose-insulin-potassium is a safe treatment with a high success rate in reversible cardiac failure.

Intravenous aspartate infusion after a coronary operation: effects on myocardial metabolism and hemodynamic state.

BACKGROUND: In a previous study glutamate infusion after coronary artery bypass grafting was associated with beneficial effects on myocardial metabolism and myocardial performance. It has been claimed that aspartate is more important than glutamate for the recovery of myocardial metabolism after cardioplegic arrest. Therefore, the metabolic and hemodynamic effects of aspartate were studied after coronary artery bypass grafting. METHODS: Fifty to 240 mL of a 0.1 mol/L aspartic acid solution was infused intravenously during 60 minutes in 10 patients early after coronary artery bypass grafting. Myocardial metabolism was studied using the coronary sinus catheter technique. RESULTS: Aspartate infusion caused a significant increase in the arterial levels of both aspartate and glutamate. This was associated with a significant increase in myocardial uptake of aspartate and a decrease in myocardial uptake of glutamate. Myocardial exchange of other substrates remained unaffected. There were no changes in hemodynamic state except an increase of heart rate and pulmonary vascular resistance. CONCLUSIONS: Interactions with glutamate metabolism, compatible with competitive inhibition of myocardial glutamate uptake, which may have outweighed potential effects of aspartate, were observed. Recognition of these amino acid interactions is important as they are used together as additives in cardioplegic solutions.

Dopamine and high-dose insulin infusion (glucose-insulin-potassium) after a cardiac operation: effects on myocardial metabolism.

Myocardial insulin resistance, in association with surgical stress, restricts the availability of carbohydrates and increases the load of free fatty acids (FFAs) on the heart. On theoretical grounds adrenergic drugs may be expected to aggravate this situation, whereas the opposite is expected from insulin. The influence of dopamine and a combination of dopamine (7 micrograms/kg body weight/min) and high-dose insulin (7 IU/kg) on myocardial energy metabolism was studied in 19 patients 4 to 6 hours after a coronary operation. Infusion of dopamine (7 micrograms/kg body weight/min) induced metabolic changes that may be unfavorable to the strained myocardium. There was an increase of the myocardial FFA load and a rise in myocardial oxygen expenditure by 60% to 70%. There changes were, however, not matched by an increase in myocardial substrate uptake. "Oxygen wastage" of FFA metabolism at high circulating catecholamine levels is suggested. There were also signs suggesting an amplified systemic trauma response: systemic oxygen consumption increased by 15%, and an increase in the arterial levels of FFAs, glucose, and ketones was observed. Divergent metabolic effects of dopamine and insulin were demonstrated. The most prominent metabolic effects of adding high-dose insulin to dopamine were a marked reduction of arterial FFA levels and a shift toward myocardial carbohydrate utilization at the expense of FFAs. Myocardial uptake of FFAs ceased. Myocardial insulin resistance may thus to a significant extent be overcome by supraphysiological doses of insulin, even during infusion of adrenergic drugs.

Routine SvO2 measurement after CABG surgery with a surgically introduced pulmonary artery catheter.

OBJECTIVE: It has been argued that the poor correlation between cardiac output and mixed venous oxygen saturation (SvO2) reduces the value of SvO2. Routine use of Swan Ganz catheters is also controversial in cardiac surgery. Here our clinical experience with a simplified method for routine hemodynamic monitoring and the short-term prognostic value of SvO2 after CABG surgery is presented. METHOD: Peroperatively an epidural catheter is routinely introduced through the outflow tract of the right ventricle into the pulmonary artery for monitoring of pressure and blood sampling. Clinical data were retrospectively retrieved from the records and related to SvO2 routinely obtained on admission to the ICU after 488 CABG procedures. RESULTS: Average SvO2 on arrival to ICU was 67+/-7%. The SvO2 value of 55% represented a cut off point below which a high incidence of complications were found. Outcome after 456 procedures with SvO2 > or = 55% compared with 32 procedures with SvO2 < 55%: mortality 0 vs. 9.4% (P = 0.0003), perioperative myocardial infarction 6.2 vs. 29% (P < 0.0001), ventilator treatment 8.9+/-10.1 vs. 25.7+/-54.9 h (P = 0.0074), ICU stay 1.4+/-1.2 vs. 2.1+/-1.7 days (P = 0.0010). CONCLUSIONS: SvO2 was of prognostic value and due to its specificity it seems particularly useful for telling which patients are unlikely to develop cardiorespiratory problems. Thus, this simple method for hemodynamic monitoring could contribute to cost containment as it seems that we can safely reserve Swan Ganz catheters for high-risk patients.

Primary idiopathic chylopericardium--a case report and review of the literature.

Primary idiopathic chylopericardium is a rare entity with obscure etiology. In recent years, a few reports have been published where the lymphatic leak and fistula were identified by combined lymphangiography and computed tomography or intraoperative thoracic ductogram. Here we report a case occurring in a previously healthy 51 year old woman, to our knowledge the first case described in Scandinavia. She presented with cough and dyspnea of about 1 year duration. Chest X-ray demonstrated enlargement of the cardiac silhouette. Echocardiography revealed pericardial effusion and at puncture pericardiocentecis 760 ml of chylous fluid was evacuated. There was no history of trauma, infection or neoplasm. She underwent extensive investigations but no apparent cause of the chylous effusion could be determined. Conservative treatment with pericardial drainage and low fat (medium chain triglyceride) diet failed. The patient was cured by surgical ligature of the thoracic duct and partial pericardectomy through a left anterolateral thoracotomy. At 12 months post operation she was doing well and echocardiography did not reveal any signs of recurrence. A brief review of the literature is presented.