Usefulness of transesophageal echocardiography for identifying the precise location of a left ventricular rupture in a patient with collapsed cardiac chamber.

We report an emergent case of cardiac tamponade due to rupture of the left ventricle. Preload and intracardiac volume were decreased by percutaneous cardiopulmonary support (PCPS), which led to the collapse of the cardiac chamber. The collapsed cardiac chamber made it difficult to diagnose cardiac abnormalities by preoperative transthoracic echocardiography (TTE). On loading fluid infusion and transfusion as volume load to improve the hemodynamic status, transesophageal echocardiography (TEE) revealed several leakages in the left ventricular myocardium. Continuous careful observation on TEE led us to a confident diagnosis of left ventricular rupture. The diagnosis by TEE also led to the employment of the appropriate procedure. TEE is useful for detecting an abnormality due to the location of the cardiac chamber and echocardiographic probe. We also note that continuous careful observation led to the employment of the appropriate procedure.

Effects of hemoglobin concentration, skull thickness, and the area of the cerebrospinal fluid layer on near-infrared spectroscopy measurements.

BACKGROUND: Previous studies documented that near-infrared spectroscopy values were affected by factors related to optical path length, such as hemoglobin concentration, the differential path length factor, skull thickness (t-skull), and the area of the cerebrospinal fluid layer (a-CSFL). Lately, the NIRO-100 (Hamamatsu Photonics, Hamamatsu, Japan) has provided a tissue oxygen index (TOI) that theoretically is not supposed to be affected by optical path length. Therefore, the authors hypothesized that TOI is not influenced by the above-described individual factors. METHODS: Cardiac surgical or neurosurgical 103 patients (65 men and 39 women; aged 63 +/- 14 yr) were studied. TOI and regional cerebral oxygen saturation (rSO2) (INVOS 4100; Somanetics, Troy, MI) were measured sequentially on patients in a resting state. The t-skull and a-CSFL were calculated using computed tomographic image slices of the head corresponding with the position of near-infrared spectroscopy sensors. The effects of these two factors, hemoglobin concentration and mean arterial pressure, on TOI and rSO2 values were evaluated by linear regression analysis. RESULTS: Simple linear regression analysis showed that mean arterial pressure (r = 0.27, P = 0.008), t-skull (r = 0.22, P = 0.034), a-CSFL (0.26, P = 0.012), and hemoglobin concentration (r = 0.42, P < 0.0001) were significant determinants of rSO2. Multiple linear regression analysis showed that hemoglobin concentration (r = 0.34, P < 0.001), a-CSFL (r = -0.252, P = 0.012), and t-skull (r = 0.22, P = 0.037) were significant determinants of rSO2. On the other hand, simple and multiple linear regression analysis showed that there was no significant determinant of TOI. CONCLUSION: rSO2 values were affected by hemoglobin concentration, a-CSFL, and t-skull, but TOI values were not affected by individual factors.

Measurements of optical pathlength using phase-resolved spectroscopy in patients undergoing cardiopulmonary bypass.

BACKGROUND: Near infrared spectroscopy (NIRS) has been used during cardiac surgery to monitor cerebral oxygenation although the validity of this technique has yet to be established. Although optical pathlength included in the algorithm for calculating NIRS values is supposed to be constant, recent evidence has suggested that optical pathlength could be affected by acute hemodilution in animals. We conducted the present study to investigate whether optical pathlength changes during cardiopulmonary bypass (CPB), and whether these changes affect NIRS values in adult patients. METHODS: Nine patients undergoing elective cardiac surgery with CPB were enrolled in this study. Optical pathlength and cerebral NIRS values (oxyhemoglobin [DeltaO(2)Hb] and tissue oxygen index) were measured by phase-resolved spectroscopy and NIRO 100, respectively. Optical pathlength, hemoglobin concentration, and NIRS values were measured at the following points: 1) after the induction of anesthesia, 2) 10 min after the start of CPB, 3) 60 min after the start of CPB, and 4) 1 h after CPB. The associations between optical pathlength and other variables were analyzed by Pearson correlation coefficients and multiple regression analysis. RESULTS: Optical pathlength significantly increased starting at 27.7-30.8 cm at 10 min, and 31.3 cm at 60 min after the start of CPB (P < 0.0001). Hemoglobin concentrations significantly decreased (from 11.2 to 7.1 g/dL at 10 min and 7.7 g/dL at 60 min P < 0.0001). There was a significant correlation (r = 0.55, P < 0.001) between percentage changes in pathlength and hemoglobin concentration. Multiple regression analysis showed that optical pathlength was a significant determinant of DeltaO2Hb. CONCLUSION: The results indicate that optical pathlength can change during CPB and its changes may affect DeltaO2Hb.

Carvedilol versus Metoprolol for the prevention of atrial fibrillation after off-pump coronary bypass surgery: rationale and design of the Carvedilol or Metoprolol Post-Revascularization Atrial Fibrillation Controlled Trial (COMPACT).

BACKGROUND: Postoperative new-onset atrial fibrillation (AF) remains the most common complication of coronary artery bypass graft surgery. Postoperative AF carries the risk of hemodynamic instability, increases the risk of thromboembolic events, and has a significant economic impact. Current guidelines recommend treatment with beta-blockers to prevent AF; information, however, is limited regarding the relative efficacy of beta-blocking agents. Carvedilol is a non-selective adrenergic blocker with anti-inflammatory, antioxidant, and multiple cationic channel blocking properties. These unique properties of carvedilol have generated interest in its use as a prophylaxis for postoperative AF. MATERIALS AND METHODS: We hypothesize that carvedilol will be more effective than metoprolol, a conventional beta(1)-selective antagonist, in suppressing newly developed AF following off-pump coronary artery bypass (OPCAB) surgery. We have designed the Carvedilol or Metoprolol Post-Revascularization Atrial Fibrillation Controlled Trial (COMPACT) to test our hypothesis in a multi-center, open-label, randomized, and controlled trial. A total of at least 650 patients will be randomized to receive an initial oral dose of either 5 mg of carvedilol twice per day or 20 mg of metoprolol tartrate three times per day following surgery. The dose of each beta-blocker will be increased to the maximum tolerated dose. The primary endpoint is the incidence of new-onset AF during the first 7 days after surgery. CONCLUSIONS: The COMPACT is the first multi-center, randomized, controlled trial to directly compare two different beta-blockers in patients following surgical coronary revascularization. Results of this trial will help to guide physicians in choosing appropriate medications following OPCAB surgery.

Cardiac output measurement using the transesophageal Doppler method is less accurate than the thermodilution method when changing PaCO2.

Cardiac output (CO) determination using transesophageal Doppler is based on the measurement of descending aortic blood flow. Because cerebral blood flow is dependent on PaCO2, an increase in PaCO2 would result in an increase of CO because of the increase in cerebral blood flow and vice versa. We enrolled 30 patients undergoing off-pump coronary artery graft surgery in the study. The CO was determined by both transesophageal Doppler and thermodilution while PaCO2 was maintained at either 30 mmHg or 40 mmHg in random order. The CO by thermodilution was significantly higher at PaCO2 of 40 mmHg (4.17 +/- 0.94 L/min) than at 30 mmHg (3.78 +/- 0.85 L/min). On the other hand, there were no significant differences in CO by transesophageal Doppler: 3.85 +/- 0.76 L/min at PaCO2 of 40 mmHg and 3.77 +/- 0.74 at 30 mmHg. Bland-Altman analysis yielded bias and precision of -0.32 and 0.49 L/min at PaCO2 of 40 mmHg, and -0.01 and 0.34 L/min at 30 mmHg. These results indicate that both methods of CO measurement are in agreement at 30 mmHg of PaCO2, but the thermodilution method provides higher values at 40 mmHg of PaCO2.

[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.

[A case report of a patient who developed hemiparaplegia with multiple cerebral infarction during thoracoabdominal aortic aneurysm repair].

To protect the spinal cord during thoracoabdominal aortic aneurysm repair, motor evoked potentials (MEP) monitoring and cerebrospinal fluid drainage are often employed. Herein, we report a case, where intraoperative diminishment of motor evoked potentials was accompanied by multiple cerebral infarction. A 63-year-old man underwent elective surgery for both thoracoabdominal aortic aneurysm and abdominal aortic aneurysm. He had a past history of cerebral infarction, resulting in Wernicke aphasia but no paralysis. Preoperative magnetic resonance angiography and echocardiography revealed occlusion of the intercostal and lumbar arteries, mild aortic regurgitation, and atherosclerotic lesions at the aortic arch as well as descending aorta. Anesthesia and muscular relaxation were maintained with fentanyl, propofol, and continuous administration of vecuronium at 0.5 mg x kg(-1) x h(-1). The thoracoabdominal aortic aneurysm was repaired under distal aortic perfusion with femorofemoral bypass. After terminating the bypass, we found that the MEP at the lower limb had disappeared. Although we reconstructed intercostal arteries under mild hypothermia and partial bypass, the amplitude of MEP remained very low. Suspecting spinal cord ischemia, we performed cerebrospinal fluid drainage immediately after the operation. On the postoperative day 4, when we stopped the cerebrospinal fluid drainage and propofol administration, his level of consciousness was poor and brain CT revealed multiple cerebral infarction. On the postoperative day 30, he was discharged from an intensive care unit with complications of hemiplagia and paraplegia. Although cerebrospinal fluid drainage may be recommended to protect spinal cord during thoracoabdominal aortic aneurysm repair, we should consider performing brain CT to exclude a risk of brain herniation secondary to cerebrospinal fluid drainage if there is a possibility of cerebral incidents.

Network computer-assisted transfusion-management system for accurate blood component-recipient identification at the bedside.

BACKGROUND: ABO-mismatched transfusions caused by human error are among the most serious problems in transfusion therapy. The major cause is misidentification of a recipient or a blood component at the bedside. STUDY DESIGN AND METHODS: A network computer-assisted transfusion-management system has been developed with bar coding as a fail-safe/fool-proof system for accurate component-recipient identification at the bedside, which allows us to monitor the usage of blood components in real time. The efficacy of this system was evaluated to prevent human errors by monitoring the transfusion process via the network and analyzing voluntary and mandatory reports with regard to transfusion errors over a 3-year period. The crossmatch-to-transfusion ratio for operations and outdate rate of RBCs were calculated to assess economic benefit. RESULTS: More than 60,000 blood components have been transfused perfectly to the intended recipients via the network, and one human error was prevented by the system. After establishment of the network system, the crossmatch-to-transfusion ratio for operations and outdate rate of RBCs have been gradually reduced from around 2.5 to 1.8 and from 3.9 to 0.32 percent, respectively. CONCLUSION: The network computer-assisted management system greatly contributes to safe and efficient transfusion therapy.

[Successful management after cardiopulmonary bypass without administration of protamine in a patient with severe food allergy--beneficial result with the use of heparin-coated bypass circuit].

We experienced the anesthetic management for cardiac surgery without the administration of protamine in a patient with severe food allergy. The patient, a 15-year-old boy, who had been avoiding many kinds of food including fish due to severe food allergy, received a correction of ventricular septal defect under cardiopulmonary bypass (CPB). To detect intraoperative drugs, including protamine, which might induce allergic reaction, we performed intradermal tests and prick tests. We used heparin-coated bypass circuit to minimize the amount of heparin necessary for anticoagulation during CPB. After CPB, hemostasis was achieved without the administration of protamine, and the patient received neither transfusion nor blood product throughout the perioperative period. Avoidance of protamine is advisable if the patient is allergic to food especially fish. The use of heparin-coated bypass circuit should be considered to establish hemostasis without protamine after CPB and to reduce blood products.

Cerebral microcirculatory changes in rat with a cardiopulmonary bypass using fluorescence videomicroscopy.

Cerebral microcirculatory changes in rat with a cardiopulmonary bypass (CPB) at normothermia was investigated in relation to cerebrovascular disorders caused by surgical operation with CPB. The mean arterial pressure was changed from 50 to 200 mmHg by changing the pump flow-rate. A non-pulsatile flow model was developed by stopping the cardiac beat using a fibrillator. The pial microcirculation was visualized using fluorescence-labeled red cells and dextran, and was directly observed under a fluorescence videomicroscope during CPB. Based on the recorded videoimages, the arteriolar diameter and red cell velocity were measured, in which single arterioles with approximately 40 microm diameter were selected among the pial arterioles. It was shown that when the arterial pressure was changed: (1) arteriolar vasodilation or constriction appeared during pulsatile flow but it disappeared during non-pulsatile flow, and (2) the arteriolar red cell velocity increased or decreased linearly during non-pulsatile flow as well as pulsatile flow. The flow-rate was almost constant at a large range of the mean arterial pressure from 60 to 160 mmHg during pulsatile flow (autoregulation), but it increased or decreased during non-pulsatile flow with an increase or decrease in mean arterial pressure, respectively. It was suggested that pulsativity might be responsible for cerebral autoregulation.

[Anesthetic experience of endoscopic umbilical cord ligation in a case of twin pregnancy with acardia].

We had an opportunity to engage in anesthetic management for umbilical cord ligation under endoscopy in a case of twin pregnancy with acardia. The patient was a 24-year-old woman. At the time of surgery, she was at 18 weeks and 2 days of pregnancy. Anesthesia was induced with diazepam 10 mg, fentanyl 150 micrograms, and vecuronium 8 mg, and it was maintained with oxygen (1 l.min-1), air (3 l.min-1) and isoflurane 0.8 to 1.2%. To prevent uterine contraction, ritodrine administration was started before surgery and continued throughout the anesthesia. Throughout the surgery, the fetuses remained immobile, with no sign of uterine contractions. However, an arterial blood sample obtained after anesthetic induction showed mild lactic acidosis, suggesting its relation to ritodrine administration. Anesthetic management for fetal surgery is unique in that it is a non-obstetrical surgical procedure performed on a pregnant patient. Particular attention must be directed to specific aspects, such as the anesthetic effect on the fetus, uterine relaxation during peri-operative period, and prevention of spontaneous abortion or premature labor after surgery. The use of tocolytic agents and fetal monitoring remain for further investigation.

Local cerebral blood flow measured by stable xenon CT during fentanyl-diazepam anesthesia.

We assessed the local cerebral blood flow (LCBF) in 40 patients under fentanyl-diazepam anesthesia. The measurement of LCBF was made using 50%-70% stable xenon with 20 min of inhalation interval and a shuttle method for computed tomography imaging. All patients were anesthetized with 5.95±1.76 µg·kg-1 fentanyl and 0.22±0.07 mg·kg-1 diazepam under mechanical ventilation during CBF measurement. The values and distribution of LCBF on non-affected hemisphere appeared to be unaltered by fentanyldiazepam anesthesia. We also assessed the cerebral carbon dioxide reactivity in 6 patients. The cerebral carbon dioxide reactivity, expressed as percentage change in LCBF per unit change in arterial carbon dioxide partial pressure, was 5.39±1.07, and there were no significant differences of reactivity among regions studied. In conclusion, we showed reference values of LCBF and carbon dioxide reactivity, measured by stable xenon-enhanced computed tomography, in patients under fentanyl-diazepam anesthesia. Carbon dioxide reactivity was preserved in all regions including gray matter, white matter, and basal ganglia.