Impact of off-pump coronary artery surgery on myocardial performance and beta-adrenoceptor function.

OBJECTIVE: To determine the hemodynamic changes during beating heart revascularization of the left anterior descending artery, the circumflex artery, and the right coronary artery as well as cardiovascular beta-adrenoceptor function before and after off-pump coronary artery bypass surgery. DESIGN: Prospective study. SETTING: University department of cardiothoracic anesthesia. PARTICIPANTS: Twenty patients scheduled for off-pump coronary artery bypass surgery using the Octopus 2 stabilizer system. INTERVENTIONS: Isoproterenol, 4 microg, was administered intravenously after induction of anesthesia and again after surgery to monitor cardiac beta-receptor function. MEASUREMENTS AND MAIN RESULTS: The hemodynamic responses to isoproterenol and cardiovascular variables were monitored before, during, and after immobilization of the target coronary artery with catheters in the radial and pulmonary arteries. During surgery on the left anterior descending artery (n = 23), stroke volume and cardiac index decreased 17 mL (21%) and 400 mL (17%). During revascularization of the circumflex artery (n = 9), stroke volume and cardiac index decreased 19 mL (28%) and 300 mL (17%). During surgery on the posterior aspect of the heart (n = 13), stroke volume and cardiac index decreased 22 mL (29%) and 400 mL (17%). All the cardiovascular variables had returned to baseline values 5 minutes after releasing the heart. The hemodynamic responses to isoproterenol were equal before and after surgery. CONCLUSION: This study provides evidence that the hemodynamic changes associated with off-pump surgery on the 3 major coronary arteries are similar and of short duration. No desensitization of cardiovascular beta-adrenoceptors was found. This finding is in contrast to the deterioration in beta-adrenoceptor function seen after surgery with cardiopulmonary bypass.

The effect of modified ultrafiltration on the amount of circulating endotoxins in children undergoing cardiopulmonary bypass.

OBJECTIVE: To determine whether the use of modified ultrafiltration during pediatric cardiopulmonary bypass (CPB) diminishes the load of circulating endotoxins. DESIGN: Single-arm prospective observational study. SETTING: A university hospital operating room and intensive care unit. PARTICIPANTS: Twenty children undergoing CPB for correction of various congenital heart diseases. INTERVENTIONS: The amount of endotoxins in plasma was measured during CPB and before and after modified ultrafiltration. The ultrafiltrate was assayed for the presence of endotoxins. Postoperatively, the children were followed with relevant infectious parameters and cultures. MEASUREMENTS AND MAIN RESULTS: The amount of endotoxins increased significantly during the CPB procedure (from a median of 1.3 ng [range, 0 to 13.7 ng] to 24.2 ng [range, 2.1 to 75.9 ng]). After termination of CPB, modified ultrafiltration was shown to lower the amount of circulating endotoxins in blood (from a median of 24.2 ng [range, 2.1 to 75.4 ng] to 9.0 [range, 0.1 to 40.6 ng]). The major bulk of this reduction in endotoxin load was retrieved in the ultrafiltrate (median of 11.9 ng [range, 0 to 12.1 ng]). CONCLUSION: This study strongly suggests that modified ultrafiltration decreases the amount of circulating endotoxins in children undergoing cardiac surgery.

Monitoring of beta-receptor sensitivity in cardiac surgery.

OBJECTIVE: To determine the repeatability of the hemodynamic response to repeated isoproterenol challenge doses to validate the standardized isoproterenol sensitivity test as an index of cardiovascular beta-receptor function. DESIGN: Prospective, single-blind, nonrandomized clinical trial. SETTING: University department of cardiothoracic anesthesia. PARTICIPANTS: Twenty middle-aged men scheduled for primary elective coronary artery bypass surgery, 10 of whom had been treated with cardioselective beta1-antagonists for more than 3 months. INTERVENTIONS: After induction of anesthesia and baseline hemodynamic evaluation, cardiac beta-receptor sensitivity was estimated from the chronotropic/inotropic responses to four intravenous 4-microg isoproterenol bolus doses. MEASUREMENTS AND MAIN RESULTS: Baseline cardiovascular function and pharmacodynamic response to the four isoproterenol challenge doses were monitored with catheters in the radial and pulmonary arteries (thermodilution). Heart rate was continuously recorded and calculated from the electrocardiogram. Baseline hemodynamic status and response to the first 4 microg of isoproterenol were similar in the 10 patients treated with beta1-antagonists and the rest of the patients. In all 20 patients, heart rate response to the three subsequent isoproterenol challenge doses decreased progressively by 28%. CONCLUSION: The standardized isoproterenol sensitivity test is unreliable for clinical monitoring of cardiac beta-adrenoceptor function.

[Lung volume reduction surgery. A new surgical therapeutic possibility for patients with emphysema]. / Lungevolumenreducerende kirurgi. Et nyt kirurgisk behandlingstilbud til patienter med emfysem.

Lung volume reduction surgery is a new surgical procedure for treatment of patients with pulmonary emphysema. At the operation the most peripheral parts of the lung are resected. Only 15-20% of the patients admitted for lung volume reduction surgery are suitable for operation. The preliminary results have demonstrated improvement in lung function in the majority of the patients. Most of the reports comprise small numbers of patients and have a short time of observation. The longest reported period of observation for a larger number of patients is 24 months and shows a continuing improvement in lung function, dyspnoea and six minute walk test. Because of the high incidence of emphysema, lung volume reduction is a procedure that could reach large extension in the future. However, better definition of criteria of inclusion and better evaluation of the operative procedures are needed.

[Do cardioselective beta-antagonists block the cardiac beta-receptor function also in the long run?]. / Blokerer kardioselektive beta-antagonister hjertets beta-receptorfunktion også på laengere sigt?

As the human cardiomyocyte expresses both beta 1 and beta 2 adrenoceptors it is to be expected that the inhibition of one species of receptors can be counteracted by the other. This hypothesis was tested in 40 middle-aged men scheduled for coronary artery bypass surgery. Half the patients had been treated with cardioselective beta 1 antagonists for more than three months while the 20 control patients had never been beta-blocked. The haemodynamic status after induction of a standardized fentanyl/midazolam anaesthesia and the sensitivity of the cardiovascular beta-adrenoceptors to isoprenaline titration were similar in both groups. In conclusion, patients chronically treated with cardioselective beta 1-blockers compensate for the perturbation to such a degree that their cardiovascular function is indistinguishable from patients who have never received beta-blockers.

Are patients chronically treated with beta 1-adrenoceptor antagonists in fact beta-blocked?

OBJECTIVE: To determine cardiovascular beta-receptor function in patients with ischemic heart disease chronically treated with beta 1-adrenoceptor antagonists. DESIGN: Prospective, single-blind, nonrandomized clinical trial. SETTING: University Department of Cardiothoracic Anesthesia. PARTICIPANTS: Forty middle-age men scheduled for primary elective coronary artery bypass surgery. Twenty patients were treated with beta 1-antagonists. INTERVENTIONS: After induction of anesthesia, increasing intravenous bolus doses of isoproterenol were administered in order to increase heart rate more than 25 BPM. From this dose-response curve, the isoproterenol dose needed to increase heart rate by exactly 25 BPM was calculated. MEASUREMENTS AND MAIN RESULTS: Baseline cardiovascular variables and the pharmacodynamic responses to isoproterenol were monitored with catheters in the radial and the pulmonary artery (thermodilution catheter). Heart rate was continuously calculated from the electrocardiogram. The hemodynamic status after induction of a standardized fentanyl anesthesia and the chronotropic and inotropic responses to the isoproterenol titration procedure were identical in the 20 beta 1-blocked patients and in the 20 control patients. The median dose of isoproterenol needed to increase heart rate 25 BPM was 10.9 micrograms in the beta-blocked patients and 9.4 micrograms in the control group. CONCLUSION: Patients chronically treated with beta 1-antagonists compensate for the perturbation to such a degree that cardiovascular beta-receptor function is in fact normal.

Subcutaneously versus subfascially administered lidocaine in pain treatment after inguinal herniotomy.

We conducted a randomized, prospective, double-blind trial to compare the efficacy of subfascial (SF) versus subcutaneous (SC) lidocaine (10 mL 1%) given in the wound postoperatively through a catheter placed in the respective layer intraoperatively. The initial pain scores were similar in the two groups before injection of lidocaine. In the SC group, there was a reduction in pain scores during rest from 4 to 3 (P > 0.05), during cough from 6 to 5 (P > 0.05), and during mobilization from 7 to 5.5 (P > 0.05) at 15 min. In the SF group, the reductions in pain scores were from 4 to 2 (P < 0.05), from 6 to 3 (P < 0.05), and from 7 to 3 (P < 0.05), respectively. Supplemental analgesics after the lidocaine administration were needed earlier in the SC group than in the SF group (P < 0.01). We conclude that postoperative pain treatment with local lidocaine application after herniotomy has a better effect when applied in the SF, rather than the SC, layer.

[Pericarditis with pericardial tumor-like manifestations in echocardiographic and magnetic resonance examinations]. / Perikardit med perikardietumorlignende manifestationer ved ekkokardiografi og magnetisk resonans undersøgelse.

A case of acute cardiac insufficiency in a 26 year old woman is described. Ultrasound examination of the pericardium was suspect for an pericardial tumor with pericardial effusion and solid masses of tumor in the fluid. Magnetic resonance imaging (MRI) gave the impression of tumor in the pericardium. Pericardiocentesis showed neither malignant cells nor growth of microorganisms. The patient recovered completely on steroid therapy and control MRI showed anatomic normalisation of the cardiac region. It is concluded that idiopatic peracarditis can mimic pericardial tumor on ultrasound and MRI investigation.