Preoperative shift from glibenclamide to insulin is cardioprotective in diabetic patients undergoing coronary artery bypass surgery.

AIM: The cardioprotective effects afforded by volatile anesthetics, i.e. isoflurane, during heart surgery may be due to preconditioning of the myocardium through the activation of KATP channels. The aims of this study were to establish whether glibenclamide prevents the isoflurane-induced cardioprotection in diabetic patients undergoing coronary surgery (CABG) and whether this cardioprotective effect can be restored by preoperative shift from glibenclamide to insulin therapy. METHODS: We enrolled 60 patients undergoing CABG. Twenty consecutive non-diabetic patients were randomized to receive conventional anesthesia (CA) or conventional anesthesia plus isoflurane (ISO) (added to the inspired oxygen before starting cardiopulmonary bypass); 40 consecutive diabetic patients in chronic treatment with oral glibenclamide were randomized to conventional anesthesia (G-CA), conventional anesthesia plus isoflurane (G-ISO), conventional anesthesia after shifting to insulin (I-CA) or conventional anesthesia plus isoflurane after shifting to insulin (I-ISO). Serum levels of cardiac troponin I (CTnI) and CK-MB, as markers of ischemic injury, were obtained 1, 24, 48 and 96 hours, postoperatively. RESULTS: Postoperative peak levels of CTnI and CK-MB were lower in ISO than in CA (0.5+/-0.3 vs 2.8+/-2.2 ng/ml, p<0.05 and 61+/-27 vs 79+/-28 U/L, p<0.05, respectively), as well as in I-CA and I-ISO than G-CA and G-ISO groups (0.5+/-0.7 and 0.7+/-0.9 vs 3.5+/-3 and 2.7+/-2.5 ng/ml, p<0.05; 47+/-7 and 41+/-5 vs 85+/-28 and 50+/-23 U/L, p<0.05, respectively). No significant differences were detected in postoperative hemodynamic variables or in-hospital outcome. CONCLUSION: This prospective randomized study shows a cardioprotective effect of preoperative administration of isoflurane during CABG. Such an effect is prevented by glibenclamide, but can be restored in diabetic patients by preoperative shift from glibenclamide to insulin.

Early diagnosis of acute mesenteric ischemia after cardiopulmonary bypass.

BACKGROUND: The aim of this study is to identify significant risk factors and eventual clinical markers associated with acute mesenteric ischemia (AMI) after cardiopulmonary bypass. METHODS: The study was retrospectively performed on a group of 19 patients (group A) undergoing cardiac surgery between January 1991 and December 1999, who developed AMI within 30 days of their hospitalization. A control group of 48 patients (group B) was compared in order to define preoperative and operative risk factors for AMI. RESULTS: At the abdominal operation, a non-occlusive mesenteric ischemia was found in every case. In-hospital mortality was 84.2% (16/19). Compared to the control, there was a significant difference in aortic cross-clamp time (p<0.001) and use of inotropic drugs (p<0.01). Postoperatively, the studied group (group A) had a significantly higher mean value of the enzymatic serum levels at any time. CONCLUSIONS: A high index of suspicion for mesenteric ischemia after cardiopulmonary bypass should be considered in patients with conditions of hypoperfusion. The early laboratory signs of AMI might be searched during the first postoperative hours.

Recovery of LV contractility in man is enhanced by preischemic administration of enflurane.

BACKGROUND: Volatile anesthetics enhance postischemic functional recovery in animal models; this effect has not been investigated in man. METHODS: Twenty-two patients undergoing coronary surgery were randomized to enflurane administration (0.5% to 2%) for 5 minutes to reduce systolic blood pressure by 20% to 25% immediately before cardioplegic arrest. Left ventricular contractility was assessed by pressure-area relations using echocardiographic automated border detection during inflow occlusion before and after cardiopulmonary bypass. Linear regression analysis in 16 patients with paired data sets assessed changes in contractility. RESULTS: The relation was highly linear (r = 0.95+/-0.02). A change of slope versus the change in x intercept was detected in controls (mean difference, 16.1 mm Hg/cm2, 95% confidence limits, 5.9 to 26.3; 2.2 cm2, 95% confidence limits, -1.1 to 5.5; p = 0.007), which was different from those of treated patients (mean difference, 0.7 mm Hg/cm2, 95% confidence limits, -2.2 to 3.7; -0.06 cm2, 95% confidence limits, -1.6 to 1.5; p > 0.2). Analysis of covariance in the overall group confirmed a significant effect of treatment (p = 0.002). CONCLUSIONS: Enflurane enhances postischemic functional recovery, possibly through pharmacologic preconditioning of myocardium.

Unilateral thoracoscopic reduction pneumoplasty for asymmetric emphysema.

OBJECTIVE: We prospectively analyzed the surgical and functional results of unilateral thoracoscopic reduction pneumoplasty which we performed by choice in patients with asymmetric emphysema. METHODS: Between October 1995 and June 1997, 119 emphysematous patients were examined and 34 were operated upon. Among these, 14 selected patients with asymmetric distribution of emphysema in the lungs underwent unilateral reduction pneumoplasty (ten right, and four left). There were 13 males and one female, with a mean age of 62 years. Eligibility criteria included bullous and non-bullous end-stage emphysema with severe limitation to daily activity. RESULTS: No patient required conversion to thoracotomy. Mean operative time ranged between 70 and 240 min with a mean of 103 min. There was no postoperative mortality but five patients developed one or more complications: five prolonged air leaks (>7 days); two pulmonary infections; one empyema. No patient required postoperative mechanical ventilation. Median hospital stay was 8 days. At the 3-month follow-up the mean FEV1 increased from 0.8 l to 1.2 l (P < 0.001). Mean FVC increased from 2.6 l to 2.9 l (P < 0.001). The Medical Research Council dyspnea score decreased from a mean of 3.2 to 1.8 (P < 0.001). CONCLUSIONS: Asymmetric distribution is a frequent finding in patients with severe emphysema. Unilateral thoracoscopic reduction pneumoplasty may represent an ideal approach in this selected group of patients.

Cardiac function and oxygen balance in septic patients during continuous hemofiltration.

The aim of this work was to study hemodynamic, oximetric and metabolic parameters in septic patients during continuous hemofiltration, in order to determine whether the changes in hemodynamic parameters can influence the oxygen utilization in peripheral tissues. 29 multiple organ failure patients with septic shock were studied during the first 48 h of continuous hemofiltration: 18 were submitted to CAVH and 11 patients were treated with CAVHD to correct ARF and fluid overload. Our data show that RVEF improves and REDVI reduces progressively during treatment, together with a significant reduction of the cardiac index after 48 h of CAVH(D). There were no significant variations in oxygen tissue parameters, while plasma lactate was reduced significantly. In conclusion, our data confirm that continuous hemofiltration may be useful in septic patients to correct fluid overload and ARF, without affecting hemodynamic stability and oxygen balance. Moreover, in septic patients, this technique improves hemodynamics, reduces the filling pressure in the right heart and reduces hyperdynamic response as CI and SVRI, without any negative effects on O2 balance.