Low-dose sevoflurane inhalation enhances late cardioprotection from the anti-ulcer drug geranylgeranylacetone.

BACKGROUND: We investigated in rabbits whether sevoflurane enhances late cardioprotection induced by geranylgeranylacetone (GGA), a gastric antiulcer drug. METHODS: S(+)-ketamine and xylazine-anesthetized rabbits were assigned to one of seven experimental groups: a control (vehicle only) group, a GGA group, a sevoflurane group, a GGA+sevoflurane group, a sodium 5-hydroxydecanoate (5HD) group, a GGA + 5HD group, and a heat stress group. All rabbits were subjected to 30 min of coronary artery occlusion followed by 3 h of reperfusion. Rabbits were pretreated with IV vehicle, GGA (10 mg/kg), or heat stress (42 degrees C for 15 min) 24 h before coronary occlusion. Sevoflurane (0.5 minimum alveolar concentration) or 5HD (5 mg/kg) were administered before myocardial ischemia. Myocardial infarct size and the area at risk for ischemia were measured, and heat shock protein (Hsp) 70 levels in each experimental group were determined. RESULTS: Compared with vehicle only, GGA significantly reduced the size of myocardial infarction in relation to the area at risk (39 +/- 10% vs 59 +/- 9%, P < 0.02). Sevoflurane enhanced the GGA-induced cardioprotection (23 +/- 17%, P < 0.05 vs GGA). The cardioprotective effect of GGA was abolished by administration of 5HD (56 +/- 15%, P < 0.01). GGA enhanced Hsp 70 expression compared with that in the control group (0.69 +/- 0.15 vs 0.36 +/- 0.05, P < 0.02). Administration of GGA with sevoflurane resulted in the same level of Hsp 70 expression as GGA (0.69 +/- 0.16, P > 0.98). CONCLUSIONS: GGA appears to reduce myocardial infarct size in association with increased Hsp 70 expression. Sevoflurane enhances the GGA-induced cardioprotective effect.

Two unusual complications associated with cardiopulmonary bypass for pediatric cardiac surgery detected by transesophageal echocardiography after decannulation.

We describe two rare cases of complications associated with cannulation for cardiopulmonary bypass during pediatric cardiac surgery detected by transesophageal echocardiography (TEE). The first patient (a 20-month-old boy, 11 kg) was scheduled for complete repair of an atrial septal defect and partial anomalous pulmonary venous connection. After decannulation of the superior vena cava, a mosaic jet was observed by means of TEE. The second patient (an 11-month-old boy, 6.4 kg), with a double outlet right ventricle, was scheduled for a hemi-Fontan procedure. After decannulation of the ascending aorta, high blood flow velocity of 4 m x s(-1) was detected by TEE. Intraoperative TEE was useful for early detection of complications associated with cardiopulmonary bypass cannulation during pediatric cardiac surgery.

Minute distance obtained from pulmonary venous flow velocity using transesophageal pulsed Doppler echocardiography is related to cardiac output during cardiovascular surgery.

PURPOSE: We studied the relationship between minute distance calculated from pulmonary venous flow (PVF) velocity tracing and cardiac output (CO) measured with thermodilution method in patients undergoing cardiovascular surgery. METHODS: In 32 patients undergoing cardiovascular surgery, simultaneous measurements of hemodynamics including CO and transesophageal pulsed Doppler signals of PVF velocity were performed before and after surgical repair. Minute distance was calculated as the product of the heart rate and the sum of time-velocity integrals of PVF. RESULTS: The minute distance after surgical intervention increased from 1121 +/- 347 cm x sec(-1) to 1764 +/- 538 cm x sec(-1) (p < 0.001; mean +/- SD), while CO increased after surgical intervention from 3.5 +/- 0.9 L x min(-1) to 5.3 +/- 1.1 L x min(-1). Simple linear regression analysis showed that minute distance was related with CO before and after surgical intervention (r = 0.81 and r = 0.76, respectively). The changes in minute distance were also related with those in CO (r = 0.80). CONCLUSION: The present study demonstrated that minute distance obtained from the pulsed Doppler tracings of PVF velocity was related with CO during cardiovascular surgery in adults. These results suggest that the changes in CO could be estimated from minute distance in pulmonary vein.

Anesthetic management of a patient undergoing cardioverter defibrillator implantation: usefulness of transesophageal echocardiography and near infrared spectroscopy.

A case of a patient with sustained ventricular tachycardia (VT) undergoing implantable cardiovertor defibrillator (ICD) implantation, using transesophageal echocardiography (TEE) and near infrared spectroscopy (NIR) is described. A 67-year-old man with sustained VT associated with old myocardial infarction underwent ICD implantation. Anesthesia was induced with fentanyl and propofol and maintained with nitrous oxide, oxygen, sevoflurane, and fentanyl. Global hypokinesis of the left ventricle was observed in the short-axis view provided by TEE. Intraoperative systolic blood pressure was maintained between 100 and 120 mmHg, and cerebral oxygenated hemoglobin (HbO2) was between 63% and 65%. During periods of induced ventricular fibrillation, systolic blood pressure decreased to 60 mmHg, HbO2 decreased to 59%, and TEE revealed cardiac arrest. These changes were transient; HbO2 returned to baseline values immediately after the restoration of normal rhythm. TEE confirmed no remarkable change in cardiac function after defibrillation testing. TEE and NIR were found to be beneficial for the anesthetic management of a patient with sustained VT who was underdoing ICD implantation.

Risk factors for perioperative myocardial ischemia in carotid artery endarterectomy.

OBJECTIVE: To identify variables associated with perioperative myocardial ischemia in patients undergoing carotid artery endarterectomy (CEA). DESIGN: Prospective, observational study. SETTING: University-affiliated hospital operating room and intensive care unit. PARTICIPANTS: One hundred twenty-eight consecutive patients who underwent CEA during a 7-year period. INTERVENTIONS: Patients had general anesthesia with sevoflurane or isoflurane. CEA was performed by standard methods with shunting if clinically indicated. Holter electrocardiogram (ECG) monitoring was performed during surgery and 24 hours after surgery. MEASUREMENTS AND MAIN RESULTS: The incidence of perioperative myocardial ischemia was examined, and perioperative risk factors were analyzed. Nineteen patients (15%) showed significant perioperative ECG abnormalities indicative of myocardial ischemia (10 patients during surgery, 12 patients after surgery, and 3 patients both during and after surgery). Multivariate analysis showed perioperative myocardial ischemia to be significantly associated with a history of angina (odds ratio, 11.68; 95% confidence interval, 2.64-51.70) and a history of hypertension (odds ratio, 14.08; 95% confidence interval, 1.51-131.04). CONCLUSION: The data indicate that perioperative myocardial ischemia defined as an ECG abnormality does not often occur in patients undergoing CEA. However, angina and hypertension may be important risk factors warranting further investigation.

Phenylephrine increases pulmonary blood flow in children with tetralogy of Fallot.

PURPOSE: Although it has been reported that the increase in blood pressure improves arterial oxygen saturation (SaO(2)) in children with tetralogy of Fallot, no prospective study has demonstrated that an increase in blood pressure induces an increase in pulmonary blood flow in these patients. The purpose of this study was to see whether a phenylephrine-induced increase in systemic blood pressure increased pulmonary blood flow, resulting in improved arterial oxygenation in tetralogy of Fallot. METHODS: In 14 consecutive children with tetralogy of Fallot (2-32 months old), transesophageal pulsed Doppler signals of left upper pulmonary venous flow (PVF) velocity were recorded before and four minutes after 10 micro g x kg(-1) of phenylephrine i.v. Simultaneously, arterial blood gas analysis and hemodynamic measurements were performed. The minute distance (MD) was calculated as the product of the heart rate and the sum of time-velocity integrals of PVF. RESULTS: Phenylephrine iv increased mean arterial blood pressure from 54 +/- 8 mmHg to 73 +/- 10 mmHg. This phenylephrine-induced hypertension significantly increased SaO(2) and MD (92.0 +/- 7.5 vs 95.0 +/- 5.0% and 1318 +/- 344 vs 1533 +/- 425 cm x min(-1), respectively). There was a significant correlation (r = 0.72) between the change in MD and the change in SaO(2). CONCLUSION: Our results suggest that the phenylephrine-induced increase in systemic blood pressure produces an increase in pulmonary blood flow in tetralogy of Fallot. Our results further suggest that this increase in pulmonary blood flow is involved in the mechanism of phenylephrine-induced improvement of arterial oxygenation in tetralogy of Fallot.

Intraoperative transoesophageal echocardiography in a low birth weight neonate with atrioventricular septal defect.

An 18-day-old male neonate (45 cm, 1.8 kg) with a history of cyanosis and congestive heart failure from an atrioventricular septal defect (AVSD) with a large left-to-right shunt was scheduled for surgical repair of the AVSD. After routine induction of anaesthesia with fentanyl and vecuronium, a 4.5-mm diameter transoesophageal echocardiography (TOE) probe was inserted into the oesophagus, and systematic echocardiographic evaluation was performed during surgery. After cardiopulmonary bypass was stopped, intraoperative TOE revealed mild residual mitral valve regurgitation. Because good left ventricular wall motion was confirmed and haemodynamic parameters were stable, cardiopulmonary bypass was not reinitiated. The patient's cardiac output was low in the postoperative intensive care unit. TOE was performed the next day to detect the source of this problem, revealed severe regurgitation compared with that observed intraoperatively. TOE was useful for evaluation of the residual mitral valve regurgitation, and we reconfirmed the importance of continuous monitoring even in a low birthweight neonate undergoing repair of a complete AVSD.

The effects of acute normovolemic hemodilution on left ventricular systolic and diastolic function in the absence or presence of beta-adrenergic blockade in dogs.

UNLABELLED: Acute normovolemic hemodilution (ANH) increases cardiac output because of a reduction in blood viscosity and enhancement of left ventricular (LV) contractility. The status of LV function, especially LV diastolic function during ANH, remains controversial. We therefore examined LV systolic and diastolic function during ANH. Sixteen dogs were anesthetized with isoflurane in the absence (Group 1) and presence (Group 2) of beta-adrenergic blockade (propranolol 1 mg/kg). LV contractility was quantified by the slope (M(w)) of the stroke work and end-diastolic volume relation. Diastolic function was evaluated with the time constant of LV relaxation (T), chamber stiffness constant (K(c)), peak LV diastolic filling rate during early filling (peak E) and atrial contraction (peak A), and ratio of peak E to peak A (E/A). Normovolemic exchange of blood (50 mL/kg) for 6% hydroxyethyl starch (ANH50) significantly increased M(w) in Group 1 but not in Group 2. In both groups, ANH50 significantly decreased T. ANH50 significantly increased peak E in both groups and peak A in Group 1, and it did not change the E/A ratio or K(c) in either group. ANH causes positive inotropic effects and enhances diastolic function without beta-blockade. Even after beta-adrenergic blockade, ANH improves diastolic function through the reduction of LV ejection impedance. IMPLICATIONS: Acute normovolemic hemodilution enhances LV (left ventricular) diastolic function by alterations in the LV loading condition produced by hemodilution, which mainly contributes to a compensatory increase in cardiac output.