This prospective study reinvestigates the effect of asymptomatic carotid artery disease on the cognitive outcome after cardiopulmonary bypass (CPB) (Harrison et al., 1989). Patients (N = 104) scheduled for cardiac surgery using CPB were classified in one of two groups based on the results of a preoperative duplex B mode Dopplcr scan of the internal carotid arteries. All patients received a neuropsychological examination before surgery, 8 days after surgery, and 6 months after surgery (n = 79). When group data are considered, patients showed evidence of selective cognitive dysfunction early after surgery. These dysfunctions were resolved by the sixth postoperative month. We found no indications that the presence of asymptomatic carotid artery disease increased the incidence of cognitive disturbances after CPB or differentially affected the postoperative performance. We conclude that mild to moderate asymptomatic carotid artery disease does not appear to play a major role in the genesis of postoperative neuropsychological sequelae. (JINS, 1996,2, 236–239.)

For forty years, heparin has been used to temporarily inhibit normal coagulation so as to permit the use of extracorporeal circulation. It has proved effective in preventing gross thrombosis and has not been compromised by changes in adjunctive practices (such as profound hypothermia; circulatory arrest), new pharmacological therapies (such as anesthetics or antibiotics), devices (such as membrane oxygenators), or during use in patients at the extremes of age. Unfortunately, heparin has been and continues to be inefficient in preserving hemostatic function during cardiopulmonary bypass resulting in undesirable bleeding after surgery.

Background and objective: The role of sevoflurane has not been studied in relation to awareness during anaesthesia. We observed the effect of sevoflurane on the incidence of awareness during cardiopulmonary bypass for open-heart surgery.

Methods: Fifty-nine patients of age >17 yr undergoing open-heart surgery with cardiopulmonary bypass were randomly assigned to two groups. In both groups, induction was with etomidate, dehydrobenzperidol and fentanyl; anaesthesia was maintained with sevoflurane, fentanyl and N2O; vecuronium was used for muscular paralysis. Group 1 (30 patients) received dehydrobenzperidol and fentanyl during cardiopulmonary bypass; Group 2 (29 patients) received sevoflurane and fentanyl. Patients were given different auditory inputs during different phases of surgery. All patients were interviewed with standard questions 8 and 24h postoperatively for evidence of explicit awareness.

Results: Five patients in the dehydrobenzperidol group gave a history of awareness (16.67%) as opposed to none in the sevoflurane group. The difference in the incidences of awareness was significant (P < 0.05), but no differences were found between the interviews conducted at 8 and 24h. Sevoflurane and opioid combination reduced the incidence of awareness in open-heart surgery.

Background and objective: Amiodarone is very effective against a variety of dysrhythmias but has poor pharmacodynamic properties and many undesired side-effects. Its short- and rapid-acting derivative E 047/1 may circumvent some of these drawbacks. It is easier to titrate while retaining the high efficacy of amiodarone and may have acceptable influences on haemodynamics and cardiac conduction in patients who develop serious, destabilizing ventricular tachydysrhythmias after cardiac surgery.

Methods: Testing E 047/1 was performed prospectively in two consecutive phase II open, clinical studies. Out of 504 patients scheduled for surgery using cardiopulmonary bypass for coronary artery grafting and/or valve repair, 35 developed serious, haemodynamically destabilizing ventricular dysrhythmias (Lown 2-Lown 4b) after surgery and were treated with a 1 mg kg−1 (pilot study, n = 15) or randomized to a 2 or 3 mg kg−1 bolus of E 047/1, followed by a 1 mg kg−1 h−1 continuous infusion for 2 h (n = 10 in each group). Dysrhythmias, PQ, QTc intervals and haemodynamics using the thermodilution technique were evaluated for up to 24 h after drug initiation.

Results: At the time of final inclusion the patients had between 6 and 12 (or more) ventricular ectopics per minute. Within the first 2–3 min of application in the pilot trial E 047/1induced a decrease of ventricular dysrhythmias to between 0 and 4 per min, a decrease that held for the duration of treatment. The area under the curve decreased from 434 (322, 855; median, quartiles) to 114 (9, 477, P < 0.01) events per hour. In the randomized trial, E 047/1 administered in either dose rapidly reduced ventricular dysrhythmias at least as effectively as in the pilot trial 565 (478, 701) to 33 (8, 238, P < 0.05) after a 2 mg bolus; 482 (339, 482) to 95 (13, 540, P < 0.01) events per hour after a 3 mg bolus. Approximately 4-6 h after drug termination, dysrhythmias reappeared in the majority of patients. In only three patients did the incidence of dysrhythmias return to inclusion criteria levels. In contrast to the pilot trial, in the randomized trial there was a slight increase of mean pulmonary artery pressure, central venous pressure and pulmonary arterial wedge pressure and a slight decrease of LCW I in both groups. E 047/1 did not cause QTc prolongation.

Conclusions: E 047/1 appears to be a safe alternative to amiodarone in the perioperative setting of cardiac surgery when serious, destabilizing dysrhythmias occur.

Background and objective The purpose of this study was to investigate retrospectively what factors contribute to the development of the type of hyperlactatemia which may follow cardiopulmonary bypass despite well-maintained oxygen delivery and a normal perioperative course.

Methods The medical records of 124 patients undergoing elective cardiac surgery using cardiopulmonary bypass were reviewed. The patients were divided into a hyperlactatemia group (n = 34), where the serum lactate concentration was > 5.0 mmol L−1 perioperatively, and a normal lactatemia group (n=90), which comprised the remaining patients.

Results The duration of cardiopulmonary bypass in the hyperlactatemia group was significantly longer than for the normal lactatemia group. Significant differences of lactate concentrations between the groups, and significant elevations of serum lactate had been observed after the start of cardiopulmonary bypass. Oxygen extraction rates were significantly reduced during the period of cardiopulmonary bypass but, on the contrary, increased in the hyperlactatemia group after surgery. The area under the curve of mean arterial pressure consisted of 5-min interval plots during the initial period of cardiopulmonary bypass in the hyperlactatemia group. This was significantly smaller than for the normal lactatemia group. Weakly significant correlations between maximal lactate and duration of cardiopulmonary bypass, and especially the area under the curve, were observed.

Conclusions It is suggested that the pathophysiology observed is based on impairment of tissue oxygen utilization. The duration of cardiopulmonary bypass and especially the occurrence of hypotension at the start of the bypass period appears to be related to the development of lactic acidosis.

Background and objective Pressure-controlled inverse ratio ventilation was compared with controlled mechanical ventilation in patients after cardiac surgery.

Methods Ten patients were ventilated after sternal closure using a Siemens Servo 900C ventilator to a target end–tidal PCO2 of 4.0 kPa. They were randomized to receive controlled mechanical ventilation or pressure–controlled inverse ratio ventilation. CO2-based data were recorded on a laptop personal computer, which together with arterial PCO2 permitted measurement of the respiratory dead space. Once measurements were complete the ventilator was switched to the other mode and new measurements taken. Results PaCO2 and VCO2 were virtually the same in both modes. Peak airway pressure (17.2±2.7 vs. 20.8±2.5 cmH2O, P < 0.01) and minute ventilation (4.9±1.1 vs. 5.3±1.1 cmH2O, P < 0.01) were less during pressure–controlled inverse ratio ventilation. Physiological dead space fraction (0.39±0.06 vs. 0.51±0.05, P <0.001), airway dead space (56±15 vs. 81±15 mL, P <0.001) and alveolar dead space fraction (0.25±0.07 vs. 0.31±0.09, P<0.01) were all less during pressure–controlled inverse ratio ventilation. There were no differences in heart rate or mean arterial pressure.

Conclusions The prolonged inspiratory period and pressure–controlled flowpattern of pressure–controlled inverse ratio ventilation reduce the alveolar and airway dead spaces, and give lower peak airway pressures, compared with conventional ventilation, in cardiac surgical patients.

Perioperative myocardial infarction or ischaemia is a potential consequence of cardiac surgery and elevated free fatty acids can increase the severity of myocardial ischaemic damage. We investigated perioperative changes in serum free fatty acids, and other serum lipids, as a consequence of using propofol infusions for cardiac surgery during cardiopulmonary bypass. Twenty-five patients undergoing elective coronary artery bypass grafting were allocated to two groups. One group of 12 patients was given a continuous infusion of propofol and the other group of nine patients received intermittent boluses of midazolam as a hypnotic agent. Serum lipid concentrations were measured at four periods perioperatively. Changes in free fatty acid concentrations were similar between the two groups. Lipid concentrations related to triglyceride in the propofol group decreased on one occasion but subsequently returned to control value. On the other hand, such values in the midazolam group remained lower than control values. Propofol is not a contraindication as an anaesthetic for cardiac surgery in respect of concern regarding the effects of free fatty acids.

Background and objective Imbalance between cerebral oxygen supply and demand is thought to play an important role in the development of cerebral injury during cardiac surgery with cardiopulmonary bypass.

Methods We studied jugular bulb oxygen saturation, jugular bulb oxygen tension, arterial–jugular bulb oxygen content difference and oxygen extraction ratio in 20 patients undergoing warm coronary artery bypass surgery (34–37°C) with pH-stat blood gas management.

Results Only two patients showed desaturation (jugular bulb oxygen saturation <50%) at 5 min on bypass, and none from 20 min onwards. Multiple regression models were performed after using bypass temperature, mean arterial pressure, cerebral perfusion pressure, haemoglobin concentration and arterial carbon dioxide tension as independent variables, and arterial–jugular bulb oxygen content difference, jugular bulb oxygen saturation, oxygen extraction ratio and jugular bulb oxygen tension as individual dependent variables.

Conclusions We found that jugular bulb oxygen saturation, jugular bulb oxygen tension and oxygen extraction ratio are mainly dependent on arterial carbon dioxide tension, and arterial–jugular bulb oxygen content difference is dependent on arterial carbon dioxide tension and the bypass temperature. Our results suggest jugular bulb oxygenation is mainly dependent on arterial carbon dioxide tension during warm cardiopulmonary bypass.

The aim of the present multiple cross-over study was to compare the effects of biphasic positive airway pressure (BIPAP) ventilation with synchronized intermittent mandatory ventilation combined with pressure support ventilation (S-IMV/PSV) in sedated and awake patients after coronary artery bypass grafting (CABG) surgery. Twenty-four patients with no evidence of preoperative respiratory dysfunction and an uncomplicated intraoperative course were investigated. The patients were randomly assigned to one of two groups starting with either BIPAP or S-IMV/PSV mode. Haemodynamic measurements and blood gas analyses were performed during sedation with 2.0 mg kg−1 h−1 propofol in the primary mode, after switching to the alternative ventilatory mode, and in the primary mode again. The same sequence of measurements was repeated in awake patients who had reached extubation criteria. In awake patients, PSV was performed instead of S-IMV. Statistical analysis of data was performed using non-parametric tests. Inspiratory peak pressure increased significantly during S-IMV/PSV in sedated patients in both groups. Other ventilatory parameters did not differ significantly between BIPAP and S-IMV/PSV in both groups. Similarly, haemodynamic parameters and blood-gas analyses did not vary with the ventilatory mode. Our results demonstrate that BIPAP ventilation has comparable effects on haemodynamics and pulmonary gas exchange compared with S-IMV/PSV and PSV when used for short-term ventilatory support in patients after cardiac surgery.

Cardiac and major abdominal surgery are associated with granulocytosis in peripheral blood. The purpose of the present study was to describe the granulocyte and monocyte oxidative burst and the expression of adhesion molecules following cardiac surgery with cardiopulmonary bypass and abdominal surgery. The ability to respond with an oxidative burst was measured by means of flow cytometry using 123-dihydrorhodamine. The adhesion molecules CD11a/CD18, CD11c/CD18, CD44 were measured using monoclonal antibodies. Blood samples from eight patients undergoing open-heart surgery were taken before surgery, 1, 5, 10 and 20 min after aortic clamping, and then 1, 5, 10 and 20 min and 1, 2 and 3 h after declamping. Samples from eight patients undergoing abdominal surgery were taken before surgery, at the end of surgery, and 2 and 3 h post-operatively. A decrease in number of granulocytes and monocytes during cardiopulmonary bypass was observed. The percentage of CD11a-positive granulocytes increased from 30% preoperatively to 75% following cardiopulmonary bypass, while CD44-positive granulocytes increased from 5% to 13%. Despite the extent of the changes, these were not significant. The oxidative burst of the granulocytes and monocytes decreased after declamping to 15% and 27% of initial values in vitro. Several hours after surgery, there was no significant difference between the two groups. These results can be explained by a granulocyte and monocyte refractory response developing subsequent to an increased per-operative oxidative burst activity, and the induction of adhesion molecules on granulocytes associated with the cardiopulmonary bypass and surgery. In conclusion, open-heart surgery with cardiopulmonary bypass was associated with a rapid and pronounced activation of leukocytes which may play a role in reperfusion injury.