Use of a novel drainage flow servo-controlled CPB for mitral valve replacement in a Jehovah's Witness.

We developed a novel open cardiopulmonary bypass (CPB) system, a drainage flow servo-controlled CPB system (DS-CPB), in which rotational speed of the main roller pump is servo-controlled to generate the same amount of flow as the systemic venous drainage. It was designed to safely decrease the priming volume while maintaining a constant reservoir level, even during fluctuations of the drainage flow. We report a successful use of a novel DS-CPB system in an elderly Jehovah's Witness patient with dehydration who underwent mitral valve replacement.

[Comparison of radial two-dimensional strain and regional wall motion abnormalities in the patients undergoing off-pump coronary artery bypass grafting].

BACKGROUND: Measurement of myocardial strain by echocardiogram is a novel approach in quantitatively assessing regional ventricular function. We investigated the relationship between left ventricular radial strain and traditional visual assessment of regional wall motion abnormalities. METHODS: We obtained midesophageal short-axis view of the left ventricle at the level of papillary muscles with a transesophageal echocardiography in 32 patients before and after off-pump coronary artery bypass grafting. Off-line analysis of echocardiogram was performed by the two independent observers. A total of 241 segments were divided into 5 grades (normal, mild hypokinesis, severe hypokinesis, akinesis, dyskinesis) according to the grading scale of ASE/SCA recommendations. A peak systolic radial strain was determined for each segment with a two-dimensional tissue-tracking method. RESULTS: The average peak systolic strain was significantly different among normal (38.4 +/- 16.1%), mild hypokinetic (30.8 +/- 14%), and severe hypokinetic (17 +/- 13.1%) segments, while no significant difference was observed between severe hypokinetic and akinetic segments. CONCLUSIONS: Our results suggest that intraoperative strain measurement by transesophageal echocardiography has a good reproducibility and allows quantitative assessment of regional ventricular function during cardiac surgery. However, the peak systolic radial strain may is less capable of differentiating segments with severely impaired wall motion.

The effect of left heart bypass on pulmonary blood flow and arterial oxygenation during one-lung ventilation in patients undergoing descending thoracic aortic surgery.

STUDY OBJECTIVE: To study the effect of left heart bypass (LHB) on regional pulmonary blood flow and arterial oxygenation during one-lung ventilation (OLV). DESIGN: Prospective, observational study SETTING: Operating room PATIENTS: 14 ASA physical status II and III patients scheduled to undergo descending thoracic or thoracoabdominal aortic surgery using LHB. INTERVENTIONS AND MEASUREMENTS: Parameters studied during OLV with 100% oxygen before and during LHB mean arterial pressure, heart rate, pulmonary artery pressure, pulmonary capillary wedge pressure, central venous pressure, cardiac index, cardiac output, arterial oxygen tension (PaO(2)), mixed venous oxygen pressure, alveolar arterial oxygen difference (P((A-a)O2)), and right upper pulmonary venous flow (RUPVF). Right upper pulmonary venous flow was measured using transesophageal echocardiography. MAIN RESULTS: With the transition to OLV, there was a significant decrease in PaO(2) and a significant increase in P((A-a)O2). However once LHB was initiated, these values improved significantly (P = 0.0007 and 0.0004, respectively) with the simultaneous increase in RUPVF (P = 0.0018). CONCLUSIONS: LHB improved pulmonary blood flow to the dependent lung and arterial oxygenation during OLV in descending thoracic aortic surgery.

Determination of right ventricular function by transesophageal echocardiography: impact of proximal right coronary artery stenosis.

STUDY OBJECTIVE: To investigate whether transesophageal echocardiography (TEE) can provide accurate information on right ventricular (RV) function in patients with right coronary artery (RCA) stenosis, given that a decrease in blood supply from the RCA may invalidate the use of single 2-D echocardiography imaging plane as a guide to RV function. DESIGN: Prospective, nonblinded study. SETTING: University hospital. PATIENTS: 30 adult patients undergoing elective cardiac or vascular procedures. INTERVENTIONS: Patients were classified into two groups according to the presence or absence of the proximal RCA (segment 1 or 2) stenosis. Group A patients had no obstructive lesions in the proximal RCA (n = 15). Group B patients had 75% or greater obstructive lesions in the proximal RCA (n = 15). MEASUREMENTS AND MAIN RESULTS: After induction of anesthesia, RV function was evaluated by both fast-response thermodilution pulmonary artery catheter and TEE. Transesophageal echocardiography-derived RV fractional area change (FAC) and tricuspid annular plane systolic excursion ratio (TAPSE ratio) were compared with thermodilution-derived RV ejection fraction (EF) using linear regression analysis. Transesophageal echocardiography-derived RV end-diastolic area (EDA) was compared with thermodilution-derived end-diastolic volume (EDV). Both methods showed a good correlation in RV, EDV, and EF in Group A, but no correlations in Group B. CONCLUSIONS: Transesophageal echocardiography does not provide reliable information on RVEF and EDV when proximal RCA stenosis is present.

Tetraplegia after coronary artery bypass grafting.

UNLABELLED: The authors present a rare case of a cervical cord dysfunction after uncomplicated coronary artery bypass grafting. The preoperative neurological examination did not reveal any abnormalities; however, the postoperative magnetic resonance image showed significant spinal canal stenosis at the same levels as high signal lesions. Although the pathophysiological basis of the case was impossible to determine retrospectively, it seems probable that placing the neck in an extended position during surgery might have aggravated a preexisting spinal canal stenosis to produce cervical injury. IMPLICATIONS: The authors present a rare case of tetraplegia after coronary artery bypass grafting. It is suggested that neck extension during surgery might have aggravated an occult preexisting cervical spinal canal stenosis to produce cervical injury.

Diltiazem facilitates inactivation of single L-type calcium channels in guinea pig ventricular myocytes.

Diltiazem is a benzothiazepine Ca2+ channel blocker used clinically for its antihypertensive and antiarrhythmic effects. We studied the mechanism of diltiazem blockade by recording L-type Ca2+ channel currents from cell-attached patches in isolated guinea pig ventricular myocytes using Ba2+ as the charge carrier. With diltiazem (200 microM) in the superfusate, multichannel currents showed a use-dependent decline in amplitude reflecting reductions in the numbers of superpositions of channel openings. Analysis of single-channel currents revealed that both open and closed times were little affected by diltiazem (50 and 100 microM). However, the rate of decay of the averaged current during 150-ms depolarization steps was significantly accelerated and the open state probability in current containing-sweeps was significantly decreased by diltiazem, suggesting that the drug accelerates transition from the activated state to the inactivated state. The effect of diltiazem on the slow gating process was studied by repetitively applying 500-1000 step pulses at selected holding potentials. Decreased channel availability by diltiazem was reflected by the increasing number of blank sweeps per run at depolarized holding potentials. These results suggest that diltiazem reduces Ca2+ influx by accelerating inactivation during action potentials, and that the use-dependent blockade is due to increases in the number of channels in a sustained closed state.

Pollution of the medical air at a university hospital in the metropolitan Tokyo area.

STUDY OBJECTIVE: To investigate the quality of medical air in a hospital in the metropolitan area. DESIGN: Prospective study. SETTING: University hospital in the metropolitan Tokyo area. INTERVENTIONS: Medical air introduced into a bio-clean operating room was sampled. MEASUREMENTS: The concentrations of nitric monoxide (NO), nitrogen dioxide (NO(2)), sulfur dioxide (SO(2)), and carbon monoxide (CO) in the medical air were measured every 30 minutes for 15 days. MAIN RESULTS: The concentrations (mean +/- SD) of NO, NO(2), SO(2), and CO were 34.4 +/- 35.0 ppb (range 0-200 ppb), 7.7 +/- 5.5 ppb (0-29 ppb), 33.8 +/- 2.9 ppb (21-46 ppb), and 1.65 +/- 0.87 ppm (0.5-7.5 ppm), respectively. The concentrations of these gases peaked at rush hours within a day. CONCLUSIONS: In the metropolitan area, we occasionally provide our patients with medical air of poor quality.

7-Nitroindazole, a selective inhibitor of neuronal nitric oxide synthase: effect on sevoflurane MAC and cerebellar cyclic GMP in mice.

PURPOSE: Considerable evidence suggests that nitric oxide (NO) plays a role in synaptic transmission in the central and peripheral nervous systems. However, whether inhibition of NO synthesis decreases minimum alveolar concentration (MAC) of inhalational anesthetics is controversial. We examined the effects of 7-nitroindazole (7-NI), a selective inhibitor of neuronal NOS (nNOS), on the MAC of sevoflurane and cerebellar cyclic guanosine monophosphate (cGMP) levels in mice. METHODS: Sevoflurane MAC and cerebellar cGMP levels were determined in mice after acute intraperitoneal or weeklong gavage feeding of 7-NI. Sevoflurane MAC and cerebellar cGMP levels after chronic treatment were measured on days 1, 4, and 7 and were repeated after an acute intraperitoneal dose of nitro g -L-arginine methylester (L-NAME). RESULTS: Acute and chronic treatment with 7-NI decreased the sevoflurane MAC by 20%-30%. Reduction of cerebellar cGMP levels was greater after intraperitoneal administration of NOS inhibitors than after gavage feeding of 7-NI. CONCLUSION: Acute or chronic selective inhibition of neuronal NOS decreases the sevoflurane MAC and cerebellar cGMP levels in mice. 7-NI permitted probing of the role of NO in perception of noxious stimuli.