Roar Stenseth

Effects of thoracic epidural analgesia on pulmonary function after coronary artery bypass surgery

OBJECTIVE A substantial reduction in lung volumes and pulmonary function follows cardiac surgery. Pain may prevent effective breathing and coughing, and as thoracic epidural analgesia may reduce postoperative pain, we investigated the effect of epidural analgesia on pulmonary function. METHODS Fifty-four male patients, under 65 years and with an ejection fraction of more than 0.5, were randomized into two groups: a control group receiving high-dose fentanyl anaesthesia and an epidural group receiving low-dose fentanyl anaesthesia + thoracic epidural analgesia. Time to awakening and time to extubation were recorded. Further, spirometric data, arterial oxygenation, pulmonary shunt, haemodynamics, use of vasoactive drugs and fluid balance were followed for up to 6 days postoperatively. RESULTS Patients with low-dose fentanyl and epidural analgesia awoke (1.6 vs 3.6 h) and were extubated (5.4 vs 10.8 h) significantly earlier than control group patients. A 50-70% reduction in forced vital capacity, forced expiratory volume in 1 s (FEV1.0) and peak expiratory flow rate (PEFR) was seen after surgery, but higher FEV1.0 and PEFR on days 2 and 3 were seen in the epidural group than in the control group. Pulmonary shunt and alveolo-arterial oxygen difference increased similarly in both groups, whereas oxygen delivery and mixed venous oxygen saturation were higher in the epidural group. Epidural analgesia gave better control of the postoperative hyperdynamic circulation. CONCLUSIONS Thoracic epidural analgesia yields a slight, but significant, improvement in pulmonary function, most likely due to a more profound postoperative analgesia.

Thoracic epidural analgesia in aortocoronary bypass surgery. II: Effects on the endocrine metabolic response.

Thoracic epidural analgesia (TEA) may offer haemodynamic benefits for patients with coronary heart disease going through major surgery. This may – in part – be secondary to an effect on the endocrine and metabolic response to surgery. We therefore investigated the effect of TEA on the endocrine metabolic response to aortocoronary bypass surgery (ACBS).

Thoracic epidural analgesia in aortocoronary bypass surgery. I: Haemodynamic effects

Tachycardia and hypertension may cause myocardial ischaemia in patients with coronary heart disease going through major surgery. Thoracic epidural analgesia (TEA) has been reported to be beneficial in this situation.

Chronic pain after cardiac surgery: a prospective study

Background: Chronic pain is a complication of several surgical procedures. The prevalence of chronic pain reported after cardiac surgery varies from 18% to 61%. However, most studies are retrospective, do not use validated instruments for pain measurement or include only pain at the sternum site. The aim of the present study was to assess chronic pain and health‐related quality of life (HRQOL) after cardiac surgery.

Prophylactic treatment with desmopressin does not reduce postoperative bleeding after coronary surgery in patients treated with aspirin before surgery

The synthetic vasopressin analog desmopressin has hemostatic properties and may reduce postoperative bleeding after coronary artery bypass grafting (CABG). A study on the effects of recent aspirin ingestion on platelet function in cardiac surgery showed a greater impairment of platelet function in patients treated with aspirin <2 days before the operation. We evaluated the effects of desmopressin on postoperative bleeding in CABG patients who were treated with aspirin 75 or 160 mg until the day before surgery. The study was a prospective, randomized, double-blinded, placebo-controlled, parallel group trial. One-hundred patients were included and divided into two groups. One group received desmopressin 0.3 &mgr;g/kg and the other received placebo (0.9% NaCl) after the neutralization of heparin with protamine sulfate. Postoperative blood loss was recorded for 16 h. The mean (sd) bleeding was 606 (237) mL in the desmopressin group and 601 (301) mL in the placebo group (P = 0.93), representing no significant difference (95% confidence interval, −107 to 117 mL). We conclude that desmopressin does not reduce postoperative bleeding in CABG patients treated with aspirin until the day before surgery.

Effects of thoracic epidural analgesia on coronary hemodynamics and myocardial metabolism in coronary artery bypass surgery

OBJECTIVE A possible influence of thoracic epidural analgesia on coronary hemodynamics and myocardial metabolism in coronary artery bypass grafting was investigated. DESIGN The study was prospective and randomized. SETTING The study was performed in a university hospital. PARTICIPANTS Thirty male patients less than 65 years of age and with ejection fraction greater than 0.5 participated. They were randomized into 3 groups: the high fentanyl (HF) group receiving high-dose fentanyl (55 micrograms/kg) anesthesia, the HF + thoracic epidural analgesia (TEA) group receiving the same general anesthesia plus thoracic epidural analgesia, and the low-fentanyl (LF) + TEA group receiving low-dose fentanyl (15 micrograms/kg) anesthesia plus thoracic epidural analgesia. INTERVENTIONS A thoracic epidural catheter, a peripheral and central venous catheter, a radial artery catheter, a thermodilution pulmonary artery catheter, and a coronary sinus reverse thermodilution catheter were inserted. MEASUREMENTS AND MAIN RESULTS Coronary circulatory parameters, myocardial oxygenation, and myocardial substrate utilization were investigated before bypass and for 9 hours after bypass. Before bypass, the most striking finding was a reduction in myocardial lactate extraction in all groups, but also coronary flow and myocardial oxygen consumption decreased compared with baseline. After bypass, the only significant finding was a lower coronary vascular resistance early postoperatively in the epidural groups, but coronary blood flow was adequate in all groups. Myocardial metabolism was essentially unchanged both with and without epidural analgesia after bypass. CONCLUSION With regard to the coronary circulation and myocardial metabolism, no hard data supporting the use of thoracic epidural analgesia in coronary artery bypass grafting were found.

Guiding Surgical Cannulation of the Inferior Vena Cava with Transesophageal Echocardiography

We studied 150 adult cardiac surgery patients to assess visualization of the venous cannula and the venous system by intraoperative transesophageal echocardiography and to register the incidence of cannulation of hepatic veins. The quality of images, the dimensions of the venous system, the position of the venous cannula, and the adequacy of venous return were registered. Acceptable image quality of the inferior vena cava and the right hepatic vein (RHV) was obtained in 95% and 87% of cases, respectively. Considerable individual variations were found in the dimensions of the venous system. The cannula position could be determined in 99% of the cases. Ten percent of venous cannulae were primarily placed in the RHV. A short distance between the eustachian valve and the RHV possibly predisposes to cannulation of the RHV. No other patient-related factors were associated with cannula position. Placement of the cannula deep in the inferior vena cava was associated with reduced venous return and may be a more important cause of reduced return than a cannula positioned in a hepatic vein.

Rectal lactate levels in endoluminal microdialysate during routine coronary surgery

The aim of this prospective study was to determine the feasibility of intestinal endoluminal microdialysis as a new method for clinical monitoring of the adequacy of splanchnic perfusion in the large bowel. A microdialysis catheter for continuous lactate, glycerol, glucose and pyruvate measurements attached to a tonometric catheter was placed into the lumen of the recto‐sigmoid junction prior to surgery in 13 patients undergoing elective cardiac surgery with cardiopulmonary bypass (CPB). Lactate was also measured in blood and muscle. CPB was associated with a 10‐fold increase in luminal lactate from 0.16 (0.01) to 1.67 (0.38) mmol.l−1 (p < 0.001). Muscular lactate increased from baseline levels 1.20 (0.21) to 1.77 (0.36) mmol.l−1 during CPB (p = 0.01), but the muscular lactate–pyruvate ratio remained unchanged. Arterial lactate increased only slightly from 0.9 (0.05) to 1.1 (0.06) mmol.l−1 (p = 0.027) during CPB. Increased lactate concentrations in the large bowel during CPB are suggestive of local lactate production consistent with impaired oxygen delivery. Intestinal endoluminal microdialysis is a potential clinically applicable method for monitoring intestinal metabolism. Combined with tonometry, microdialysis provides the opportunity to monitor both circulation and metabolism in the rectal mucosa.

The influence of thoracic epidural analgesia alone and in combination with general anesthesia on cardiovascular function and myocardial metabolism in patients receiving β-adrenergic blockers

Thoracic epidural analgesia combined with chronic beta-adrenergic blocker medication may cause cardiac depression. We investigated the cardiovascular and myocardial metabolic effects of a T1-T12 epidural block in 18 patients (age < 65 yr, ejection fraction > 0.5), receiving chronic beta-adrenergic blocker medication and scheduled for aortocoronary bypass surgery. After randomization into a light or deeper general anesthetic group, the cardiovascular and myocardial metabolic effects of a subsequent general anesthesia induction were investigated. Thoracic epidural analgesia induced a moderate decrease in mean arterial pressure, coronary perfusion pressure, free fatty acids, and myocardial consumption of free fatty acids. General anesthesia with thiopental (2-4 mg/kg) and a low fentanyl dose (5 micrograms/kg) increased heart rate, coronary perfusion pressure, and coronary vascular resistance, whereas mean pulmonary arterial pressure and pulmonary capillary wedge pressure decreased. After thiopental (2-4 mg/kg) and a high fentanyl dose (30 micrograms/kg), mean arterial pressure and left ventricular stroke work index decreased. We conclude that a T1-T12 epidural block in well sedated, beta-adrenergic blocked patients does not induce clinically significant cardiovascular effects. Induction of general anesthesia was well tolerated, but the light general anesthetic could not prevent an increase in heart rate and coronary vascular resistance, whereas the deeper anesthetic induced slight myocardial depression. No effect on the atrioventricular conduction, as measured by the PQ-time, was noted.

Health-related quality of life three years after coronary surgery: A comparison with the general population

Objectives. To assess health-related quality of life (HRQOL) in patients three years after coronary artery bypass grafting (CABG) compared to the general Norwegian population, with emphasis on age and gender-differences. Design. A cross-sectional postal survey of patients who underwent CABG in 2000. HRQOL was assessed using the Short Form 36 (SF-36). Subgroup analyses were performed according to age (<70 versus ≥70 years) and gender. Results. Of 233 eligible patients 203 responded (mean age 67.6 years, 17% females). Patients reported better scores on bodily pain than the general population (p = 0.008), but did not differ on other subscales of SF-36. Younger patients tended to score lower, older patients higher than the general population on HRQOL. Female patients reported lower HRQOL than the general female population and reported significantly lower scores than male patients on 3 of 8 subscales. Conclusions. Three years after CABG the HRQOL is comparable to the general Norwegian population even in older patients. The older patients reported less pain than the general population.