Effects of low-dose milrinone on weaning from cardiopulmonary bypass and after in patients with mitral stenosis and pulmonary hypertension.

The phosphodiesterase inhibitor milrinone is usually preferred in patients with pulmonary hypertension and myocardial dysfunction after cardiopulmonary bypass. We investigated the effects of low-dose milrinone on pulmonary hypertension in the immediate pre- and postoperative period. Forty-seven patients were randomized to the control and milrinone groups. All patients had mean pulmonary artery pressure greater than 30 mmHg and pulmonary capillary wedge pressure greater than 20 mmHg and were candidates for mitral valve replacement for rheumatic mitral stenosis. Twenty-four patients received a loading dose of milrinone 25 microg/kg(-1) during weaning from cardiopulmonary bypass, followed by a maintenance dose of 0.25 microg/kg(-1)/min(-1) to the end of the surgery. Cardiac output and other hemodynamic variables were noted at induction, weaning from bypass, and postoperative 1 h. Pulmonary artery pressure, capillary wedge pressure, and central venous pressure were significantly lower in the milrinone group during weaning after cardiopulmonary bypass, while other variables were roughly similar. However, patients in the control group required higher doses of vasodilators, inotropes, and antiarrhythmic agents. Mean arterial pressure in the milrinone group was significantly lower at 1 h postoperatively than in the control group; however, the patients did not need many more vasopressors. Fluid restriction and diuretic agent use were more significant in the control group. Systemic arterial hypotension and vasopressor requirements with milrinone use at inotropic doses were not observed at the doses used for the study. A total of 21.7% of the patients in the control group required vasopressors in the perioperative period. Both groups demonstrated similar hematologic variables except that the hemoglobin level in the control group was significantly lower during postoperative days 1 and 7. Low-dose milrinone for a short-term during weaning from cardiopulmonary bypass may be used in patients with mitral stenosis and pulmonary hypertension for its effects on pulmonary artery pressures, less inotropic and vasopressor requirements, and fluid balance.

Effects of propofol and midazolam on lipids, glucose, and plasma osmolality during and in the early postoperative period following coronary artery bypass graft surgery: a randomized trial.

It is not clear how levels of serum lipids and glucose and plasma osmolality change during propofol infusion in the pre- and postoperative period of coronary artery bypass graft surgery (CABG). This prospective, randomized, controlled trial evaluated changes in these parameters during propofol or midazolam infusion during and in the early postoperative period following surgery. Twenty patients undergoing CABG were randomized preoperatively into two groups: 10 patients received propofol (induction 1.5 mg/kg, maintenance 1.5 mg kg(-1) h(-1)) and 10 patients received midazolam (induction 0.5 mg/kg, maintenance 0.1 mg kg(-1) h(-1)). Both groups also received fentanyl (induction 20 mug/kg, maintenance 10 microg kg(-1)). Serum lipids, glucose, and plasma osmolality were measured preinduction, precardiopulmonary bypass, at the end of cardiopulmonary bypass, at the end of surgery, and 4 and 24 h postoperatively. In the propofol group, we observed a significant increase in triglycerides and very low-density lipoprotein levels 4 h postoperatively. In the midazolam group, we observed a significant decrease in low-density lipoprotein, cholesterol at the end of cardiopulmonary bypass, end of surgery, and 4 and 24 h postoperatively and significant increase in osmolality at the end of cardiovascular bypass. Changes in glucose levels did not differ significantly different between the two groups. In patients with normal serum lipids, glucose, and plasma osmolality undergoing CABG, propofol infusion for maintenance anesthesia is not associated with dangerous changes in serum lipids, glucose, and plasma osmolality compared with midazolam. A propofol infusion technique for maintenance of anesthesia for cardiac surgery where serum lipids and glucose may be of concern could be recommended as an alternative to midazolam.

Effects of different cardioplegic solutions on nitric oxide release from coronary vasculature in diabetic patients undergoing coronary artery bypass surgery.

OBJECTIVE: The aim of this study was to compare the effects of two different cardioplegic solutions on nitric oxide (NO) release from coronary vasculature in patients with type II diabetes mellitus undergoing coronary artery bypass grafting (CABG) surgery. METHODS: Forty patients undergoing elective CABG surgery were randomized to be given crystalloid (Group 1) or blood (Group 2) cardioplegia. Aortic and coronary sinus blood samples were taken at three different time periods and the release of NO from the coronary vasculature was determined by measuring its stable end-products, nitrite and nitrate. The difference between the aortic and coronary sinus concentrations of nitrite and nitrate represents the amount of NO released by coronary vascular bed. RESULTS: Before application of aortic cross-clamp, at T1 period, the levels of nitrite/nitrate from the coronary vasculature were similar in both groups (6.53+/-1.21 microM vs 6.07+/-1.24 microM , p>0.05). However after the removal of cross-clamp, a significant decrease in NO was observed in Group 1 as compared with Group 2 (4.21+/-0.73 microM vs 4.92+/-1.02 microM, p<0.01) . This decrease persisted at T3 period, after 30 minutes of reperfusion in group 1 being significantly different from group 2 (3.86+/-0.49 vs 4.37+/-0.72 microM, p<0.05). CONCLUSION: This study has shown that in patients with type II diabetes mellitus crystalloid cardioplegia causes a decrease in the release of NO from coronary vascular bed during aortic cross-clamp and reperfusion period whereas more physiologic blood cardioplegia did not. Our findings indicate that blood cardioplegia protects endothelial function better than crystalloid cardioplegia in diabetic patients.

A comparison of the acute hemodynamic effects of inhaled nitroglycerin and iloprost in patients with pulmonary hypertension undergoing mitral valve surgery.

BACKGROUND: Since the presence of pulmonary hypertension (PHT) affects the prognosis of the patients, it is important to manage and evaluate PHT. The aim of this study was to compare the hemodynamic effects of inhaled nitroglycerin and iloprost during early postoperative period, in patients with PHT undergoing mitral valve replacement surgery. MATERIALS AND METHODS: One hundred patients with PHT (mean pulmonary artery pressure (MPAP) >25 mmHg at rest), were randomized to receive either inhalation of nitroglycerin (group I; n=50) or iloprost (group II; n=50) in the postoperative period. In both groups, baseline hemodynamic parameters were recorded before the treatment (T(0)). Then, patients in group I received 20 microg.kg(-1) nitroglycerin and those in group II received 2.5 microg.kg(-1) iloprost. The same parameters were recorded immediately after the end of the treatment (T(1)). RESULTS: In both study groups MPAP and pulmonary vascular resistance (PVR) were found to be significantly lower at T(1) when compared to that of T(0) period (p<0.05). MPAP and PVR were significantly lower and mean arterial pressure (MAP) was significantly higher in group II when compared to group I at T(1) period (p<0.05). In addition to decreases in PVR and MPAP, iloprost also increased cardiac output (CO)(4.9+/-1.3 vs 5.1+/-0.9, p<0.05) and stroke volume (SV)(48+/-13 vs 56+/-13, p<0.05). CONCLUSION: Inhaled iloprost and nitroglycerin, both effectively reduce MPAP and PVR without affecting MAP, systemic vascular resistance (SVR) and CO. However, iloprost seems to be a more powerful pulmonary vasodilator, therefore we suggest iloprost inhalation in patients with severe PHT.

Continuous positive airway pressure does not improve lung function after cardiac surgery.

PURPOSE: Despite the well-documented impairment of pulmonary function after cardiopulmonary bypass, effective precautions and ideal management strategies for this problem are still under debate. This study aimed to evaluate the effects of continuous positive airway pressure (CPAP) applied during cardiopulmonary bypass on respiratory and hemodynamic variables. METHODS: In this randomized, prospective, controlled trial, 120 male patients, aged 45 to 70 yr undergoing first-time elective bypass surgery, were randomly assigned to receive either 10 cm H2O of CPAP (Group I; n = 60) during cardiopulmonary bypass, or serve as control (Group II; n = 60), where the patient's lungs were vented to atmosphere during the bypass period. RESULTS: Alveolar-arterial oxygen partial pressure difference and shunt fraction were significantly higher in the control group compared with the CPAP group after cardiopulmonary bypass (T2) and after closure of sternum (T3), (P < 0.05). No differences between groups with respect to hemodynamic variables were observed at any time. Postoperative pulmonary function variables were lower in both groups compared to baseline values. CONCLUSIONS: Continuous positive airway pressure administered during cardiopulmonary bypass decreased shunt fraction and alveolar-arterial oxygen partial pressure difference during surgery, but had no sustained effect on either variable postoperatively. We conclude that, in patients with normal preoperative pulmonary function, application of 10 cm H2O CPAP does not improve lung function after cardiac surgery.

[The effects of insulin given prior to release of cross-clamp on coronary sinus lactate levels in coronary artery surgery]. / Koroner arter cerrahisinde kros-klemp alinmadan önce yapilan insülinin koroner sinüs laktat seviyeleri üzerine etkileri.

OBJECTIVE: The aim of this study is to evaluate the effects of single dose insulin, given prior to reperfusion, in patients undergoing coronary artery bypass surgery (CABG). METHODS: One hundred and twenty patients were prospectively randomized to be given either insulin (Group 1;n=60), or saline (Group 2;n= 60). Blood samples were taken 15 minutes before the reperfusion and insulin was given (0.3 IU/kg) to the patients in Group 1. Arterial and coronary sinus blood samples were taken, after the release of aortic cross-clamp (0. min), and 5th -10th -15th minutes of reperfusion. Arterial and coronary sinus lactate and glucose levels, postoperative insulin, inotropic and intraaortic balloon pump requirements; need for defibrillation and postoperative dysrhythmia, creatine kinase- MB (CPK-MB) levels, and length of stay in intensive care unit (ICU) and hospital were compared. RESULTS: In Group 1, arterial lactate levels were found to be lower at 0.min, coronary sinus lactate levels were found to be lower at 0-5-10th minutes of reperfusion compared to Group 2. Similarly, defibrillation, glucose, postoperative insulin and inotrop requirements, postoperative arrhythmia and length of ICU stay were lower in Group 1. The CPK-MB levels and length of hospital stay were similar in all patients. CONCLUSIONS: We conclude that single dose insulin given before the reperfusion period, has positive perioperative effects. Therefore it can be used in patients undergoing CABG surgery to decrease ischemia-reperfusion injury.

Postoperative effects of opioid analgesics administered via continuous perfusion and patient controlled analgesia after open heart surgery.

Critical care nurses and physicians are familiar with the principles of patient controlled analgesia and the opioid analgesics' regimens and observations necessary for pain control in the postoperative cardiac surgical patients. The objective of the study was to compare the effects of morphine, fentanyl, meperidine, remifentanil and tramadol which were administered by patient controlled analgesia and continuous intravenous infusion combination on the various parameters. This study was designed as prospective randomised trial. Fifty patients undergone open heart surgery with sternotomy were entered equally into five randomized groups. Visual analog scale was used by researcher nurse to assess the patient' pain status. Respiratory rate, heart rate and blood gases (pO2, pCO2, SaO2), radial arterial blood pressures were measured in the first 24 hrs postoperatively. Bolus requirements were determined by physicians and side effects of the analgesics were documented. Fentanyl group showed statistically higher levels of mean pO2 (p=0.002). Meperidine had the lowest number of bolus doses (p=0.001). There were no significant differences between the groups for pain management except higher visual analog scales on tramadol. Headache, stomach-ache and, palpitations were observed in our patients. Remifentanil, meperidine, fentanyl and morphine showed similar effect with each other for pain relief except tramadol.

Effect of nitroglycerin inhalation on patients with pulmonary hypertension undergoing mitral valve replacement surgery.

BACKGROUND: The aim of this study was to investigate the postoperative hemodynamic effects of nitroglycerin inhalation on patients with pulmonary hypertension undergoing mitral valve replacement surgery. METHODS: Twenty patients who underwent mitral valve replacement surgery were included in the study. In the surgical intensive care unit, at T0 (before the inhalation of nitroglycerin), basal systemic and pulmonary hemodynamics were recorded. Then, 2.5 microg x kg-1 x min-1 nitroglycerin liquid nebulized by a 2-l gas flow of 40% oxygen and air mixture was administered to the patients who were diagnosed as having pulmonary hypertension (mean pulmonary arterial pressures > 25 mmHg). The same parameters were measured at the first (T1), third (T2), and fifth (T3) hours after the beginning of this treatment and 1 h after the end of nitroglycerin inhalation (T4). RESULTS: There were no statistically significant differences at T0, T1, T2, T3, or T4 with respect to heart rate, mean arterial pressure, systemic vascular resistance, cardiac index, mixed venous oxygen saturation, arteriovenous oxygen content difference, or arterial carbon dioxide tension. However, mean pulmonary artery pressure, pulmonary vascular resistance, and intrapulmonary shunt fraction were significantly lower, and the arterial oxygen tension/fraction of inspired oxygen ratio was higher at T1, T2, and T3 when compared to that of T0 and T4. CONCLUSION: The results suggest that nitroglycerin inhalation produces a significant reduction in both mean pulmonary artery pressure and pulmonary vascular resistance in patients after mitral valve operations without reducing mean arterial pressure and systemic vascular resistance. Therefore, it might be a safe and useful therapeutic intervention during the postoperative course.