Clinical comparison of an echocardiograph-derived versus pulse counter-derived cardiac output measurement in abdominal aortic aneurysm surgery.

OBJECTIVE: To compare cardiac output (CO) measurements acquired using the Flotrac/Vigileo system (Edwards Lifesciences, Irvine, CA) and CO measured by transesophageal echocardiography using the product of the aortic valve area, the time integral of flow at the same site, and the heart rate during abdominal aortic aneurysm (AAA) surgery. DESIGN: A prospective clinical study. SETTING: Cardiac surgery operating room of 1 heart center hospital. PARTICIPANTS: Twenty patients undergoing elective AAA surgery. INTERVENTIONS: CO was determined simultaneously using the Flotrac/Vigileo system (CO(AP)) and transesophageal echocardiography (CO(TEE)) as the reference method at 8 time points during AAA surgery. MEASUREMENTS AND MAIN RESULTS: One hundred sixty simultaneous datasets were obtained. The authors observed a significant correlation between CO(AP) and CO(TEE) values (R = 0.56, p < 0.001). Bland-Altman analysis of CO(AP) and CO(TEE) showed a bias of 0.12 L/min and limits of agreement from -1.66 to 1.90 L/min, with a percentage error of 41%. Just after aortic clamping, CO(AP) significantly increased, but CO(TEE) decreased in comparison with previous measurements. There was a significant association among changes in CO(AP) and pulse pressure, heart rate, and central venous pressure (CVP). However, changes in CO(TEE) were only associated with variations in heart rate. CONCLUSIONS: CO(AP) values were not clinically acceptable for use in AAA surgery because of wide variations during aortic clamping and declamping. Changes in pulse pressure, heart rate, and CVP were associated with significant changes in CO(AP), whereas only changes in heart rate showed associated changes in CO(TEE).

Changes of motor evoked potentials during descending thoracic and thoracoabdominal aortic surgery with deep hypothermic circulatory arrest.

BACKGROUND: Paraplegia is a serious complication of descending and thoracoabdominal aortic aneurysms (dTAAs and TAAAs) surgery. Motor evoked potentials (MEPs) enable monitoring the functional integrity of motor pathways during dTAA and TAAA surgery. Although MEPs are sensitive to temperature changes, there are few human data on changes of MEPs during mild and deep hypothermia. Therefore, we investigated changes of MEPs in deep hypothermic circulatory arrest (DHCA) in dTAA and TAAA surgery. METHODS: Fifteen consecutive patients undergoing dTAA and TAAA surgery using DHCA were enrolled. MEPs were elicited and recorded during each degree Celsius change in nasopharyngeal temperature during both the cooling and rewarming phases. Hand and leg skin temperature were also recorded simultaneously. RESULTS: In the cooling phase MEP amplitude decreased lineally in both the hand and leg. The MEP disappeared at ~16°C in both the hand and leg in 10 of 15 patients, but was still elicited in 5 patients. In the rewarming phase MEP in the hand recovered before the temperature reached 20°C for eight patients and 25°C for the other seven patients. In contrast, MEP in the leg recovered below 20°C for two patients and 30°C for three patients. For the other eight patients MEP waves did not recover during the rewarming phase. CONCLUSION: In the cooling phase of DHCA, MEP disappeared at ~16°C in some patients but was still elicited in others. MEP recovered below 25°C in the hand. Recovery of MEP in the leg was, however, extremely variable.

The efficacy of motor-evoked potentials on cerebral aneurysm surgery and new-onset postoperative motor deficits.

Surgical clipping may cause stenosis of parent arteries or occlusion of perforating arteries in cerebral aneurysm surgery. To prevent postoperative motor deficits, motor-evoked potentials (MEPs) have been used. This enables to detect cerebral ischemia. However, the rate of false negatives (motor deficits with preserved MEP) has been relatively higher than in aortic surgery. We hypothesized that postoperative motor deficits with preserved intraoperative MEP do not always represent false negatives. We reviewed medical records of patients for cerebral aneurysms surgery with transcranial MEP monitoring from September 2003 to March 2009. We reviewed aneurysm location and size, abnormal computed tomography findings, and clinical outcome. Motor status was evaluated immediately after extubation and anytime when the symptom of motor deficits was found. One hundred and eleven patients underwent cerebral aneurysm clipping with transcranial MEP. Ninety-eight patients manifested no intraoperative MEP changes and no postoperative motor deficits. Six patients showed intraoperative MEP changes, resulting in no motor deficits in 4 patients with MEP recovery and hemiparesis in 2 without MEP recovery. Four patients of 6 had aneurysm in anterior choroidal artery (AchA). Other 6 patients showed postoperative motor deficits despite preserved intraoperative MEP. Two of 6 patients showed no motor deficits just after extubation, but developed deficits 5 hours after coming out of anesthesia. Only 1 of the 6 patients had aneurysm in AchA. In AchA aneurysm surgery, intraoperative MEP monitoring seems to be useful. False negative in MEP monitoring may include new-onset hemiparesis despite preserved intraoperative MEP.

Jugular bulb desaturation during off-pump coronary artery bypass surgery.

PURPOSE: Off-pump coronary artery bypass grafting surgery (OPCAB) frequently results in significant jugular bulb desaturation. Although jugular bulb desaturation during OPCAB may be associated with postoperative cerebral injury, routine jugular bulb oximetry appears to be invasive and expensive. We hypothesized that intraoperative hemodynamic compromise during OPCAB due to cardiac displacement is associated with jugular bulb desaturation which correlates with specific hemodynamic and physiological changes. METHODS: Hemodynamic and physiological data were measured at the following points: (1) before anastomosis of the coronary artery (baseline); (2) during anastomosis of the left anterior descending artery; (3) during anastomosis of the circumflex branch or posterior descending artery; and (4) after chest closure. Arterial, mixed venous, and jugular venous bulb blood gas analyses were performed serially. RESULTS: Jugular bulb desaturation (or= 8 mmHg were likely predictors of the occurrence of jugular bulb desaturation. CONCLUSION: Changes in S(VO2) and Pa(CO2) were associated with jugular bulb oxygen saturation, and S(VO2) or= 8 mmHg had a significant odds ratio for jugular bulb desaturation. We suggest that achieving normal values of S(VO2), Pa(CO2) and CVP may be important to prevent cerebral desaturation during OPCAB.

[Giant cerebral aneurysm with fontan circulation].

The population of children undergoing successful surgery for congenital heart disease (CHD) continues to increase. Increasing number of patients with a Fontan circulation is reaching adulthood and requiring anesthesia for noncardiac surgeries. We anesthetized a patient with a Fontan circulation (9 years old) for giant internal carotid-ophthalmic artery aneurysm trapping. There was a difficulty in cannulating internal jugular vein for measuring central venous pressure because of abnormal collateral arteries around the internal jugular vein. Central venous pressure of around 15 mmHg seemed appropriate to keep good hemodynamic condition during this surgery. In this condition, cerebral cortex was not edematous. Careful management of circulatory volume stabilized hemodynamic state. However, when heart rate decreased below 75, ectopic atrial rhythm occured. Anesthetic time was 13 hr and 40 min. The patient was extubated in the operating room. We have to take into consideration that there are anatomical abnormalities and arrhythmia in the patients with a Fontan circulation.

[Successful weaning from cardiopulmonary bypass with administration of landiolol hydrochloride in a patient with hypertrophic obstructive cardiomyopathy].

A 14-yr-old boy with hypertrophic obstructive cardiomyopathy, undergoing percutaneous transluminal septal myocardial ablation suffered dissection of the left main coronary artery during the procedure. Sixty minutes after absolute ethanol administration, he was transferred to the operating room for emergency coronary artery bypass grafting, mitral valve replacement and cardiomyectomy. Transesophageal echocardiography (TEE) findings after the induction of anesthesia were: general hypokinesis, mitral regurgitation 1+, left ventricular outflow tract pressure gradient of 11 mmHg and no blood flow in the left anterior descending coronary artery. On aorta declamping, ECG showed ventricular fibrillation and ventricular tachycardia, and the sinus rhythm was restored after 100 mg lidocaine i.v. and DC conversion. TEE revealed severe hypokinesis in antero-septal and hypokinesis in posterolateral wall, respectively. Since supraventricular tachycardia (HR 130 140 bpm) disabled the intraaortic balloon pump (IABP) synchronization, HR was maintained 90-100 bpm with landiolol hydrochloride (10-40 micrograms x kg(-1) min(-1)) and synchronization was obtained. Systolic BP was maintained 90-120 mmHg with norepinephrine (0.2-0.3 micrograms x kg(-1) x min(-1)) and the patient could be successfully weaned from CPB with cardiac index 2.0 and mixed venous oxygen saturation 59%. On the 2nd postoperative day (POD), he was weaned from IABP and ventilator. On the 6 th POD, he was discharged from the ICU.

Effect of high-frequency jet ventilation on heart rate variability.

We investigated the effects of high-frequency jet ventilation (HFJV) on heart rate variability in nine patients during fentanyl (10µg·kg-1) anesthesia using power spectral density analysis. ECG and arterial pressure were recorded during intermittent positive pressure ventilation (IPPV) (tidal volume 8 ml·kg-1, respiratory rate 0.25 Hz) and during HFJV [5 Hz, 2.5 kg·(cm2)-1]. The R-R interval time series obtained were analyzed by the autoregressive method, and low-frequency (LF) (0.05-0.15 Hz) power and high-frequency (HF) (0.20-0.50 Hz) power from R-R interval spectra were used for statistical comparison. LF power did not change during IPPV and HFJV (108.8±41.6 ms2 vs 105.8±22.4 ms2, mean±SE). HF power was detected during IPPV (65.1±14.3 ms2); however, it was not detected during HFJV. Plasma levels of norepinephrine and epinephrine were significantly higher during HFJV than during IPPV. The mean R-R interval, arterial pressure, and arterial blood gas data did not differ between IPPV and HFJV. These data indicate that, during fentanyl anesthesia, HFJV influences mainly the respiratory frequency fluctuation of heart rate variability, and they suggest that alteration of breathing patterns caused by HFJV might be involved, as well as elevated sympathetic neural outflow to the heart.