Electroencephalographic effect of age-adjusted 1 MAC desflurane and sevoflurane in young, middle-aged, and elderly patients.

PURPOSE: We examined the hypothesis that 1 minimum alveolar concentration (MAC) of desflurane and sevoflurane provides different depth of anesthesia. METHODS: One hundred and twenty young (20-30 years), middle-aged (31-65 years), and elderly (66-80 years) patients were randomly allocated to receive either desflurane or sevoflurane (n = 20, each group). General anesthesia was induced with propofol 2 mg/kg bolus and remifentanil 0.25 µg/kg/min, which was stopped after tracheal intubation. Maintenance of anesthesia was started with an end-tidal concentration of desflurane or sevoflurane at age-adjusted 1 MAC and maintained for 10 min, followed by 1-min assessment of bispectral index (BIS), 95% spectral edge frequency (SEF95), and amplitude of the electroencephalogram taken at 10-s intervals. RESULTS: BIS and SEF95 in patients receiving 1 MAC desflurane were significantly lower than those receiving 1 MAC sevoflurane including all age groups [35 (29, 39) vs. 41 (38, 49); 12.53 (10.99, 13.95) Hz vs. 14.42 (12.99, 17.17) Hz median (25, 75 percentile), respectively, P < 0.001 for both]. Both BIS and SEF95 in young patients were lower than in middle-aged and elderly patients receiving either desflurane or sevoflurane (P < 0.001 for both). There were no differences in amplitude between patients receiving desflurane and sevoflurane. CONCLUSIONS: BIS as well as SEF95 were lower in patients receiving 1 MAC desflurane than those receiving 1 MAC sevoflurane, suggesting that desflurane provides higher depth of anesthesia than sevoflurane at 1 MAC.

High-power and highly efficient amplification of a radially polarized beam using an Yb-doped double-clad fiber.

We demonstrated the amplification of a radially polarized beam by using an Yb-doped double-clad fiber. The output power of the amplified beam reached 21 W at pump power of 30 W. The generation of amplified spontaneous emission was suppressed by applying a seed beam with sufficient power. Although the intensity distribution of the seed beam was well maintained after the amplification, partial transformation of radial polarization to azimuthal polarization was observed.

[Low dose vasopressin is effective for catecholamine-resistant hypotension after resection of pheochromocytoma].

The perioperative management of pheochromocytoma is challenging for anesthesiologists and persistent hypotension secondary to cathecholamine depletion after tumor resection can be refractory to treatment. A 64-year-old man underwent right adrenalectomy for treatment of massive pheochromocytoma. Doxazosin administration was started and increased gradually to 12 mg daily. He was premedicated with doxazosin on the day of the surgery. Induction was uneventful but there was a sudden increase of blood pressure with tachycardia on handling of tumor which was controlled by intravenous remifentanil, landiolol, diltiazem, and magnesium sulfate. With dissection of the tumor, the blood pressure dropped to 65/40 mmHg, which was resistant to fluid and cathecholamine treatment. After commencement of low dose vasopressin administration (two boluses of 0.08 U followed by 1.6 U x hr(-1)), blood pressure gradually recovered to normal ranges. Low dose vasopressin can be safely used to treat postadrenalectomy hypotension and also can reduce the cathecholamine dose.

In vivo two-photon imaging of mouse hippocampal neurons in dentate gyrus using a light source based on a high-peak power gain-switched laser diode.

In vivo two-photon microscopy is an advantageous technique for observing the mouse brain at high resolution. In this study, we developed a two-photon microscopy method that uses a 1064-nm gain-switched laser diode-based light source with average power above 4 W, pulse width of 7.5-picosecond, repetition rate of 10-MHz, and a high-sensitivity photomultiplier tube. Using this newly developed two-photon microscope for in vivo imaging, we were able to successfully image hippocampal neurons in the dentate gyrus and obtain panoramic views of CA1 pyramidal neurons and cerebral cortex, regardless of age of the mouse. Fine dendrites in hippocampal CA1 could be imaged with a high peak-signal-to-background ratio that could not be achieved by titanium sapphire laser excitation. Finally, our system achieved multicolor imaging with neurons and blood vessels in the hippocampal region in vivo. These results indicate that our two-photon microscopy system is suitable for investigations of various neural functions, including the morphological changes undergone by neurons during physiological phenomena.

Partially unroofed coronary sinus with persistent left superior vena cava: the utility of two and three-dimensional transesophageal echocardiography: a case report.

Unroofed coronary sinus (URCS) is a rare cardiac anomaly, in which communication occurs between the coronary sinus (CS) and the left atrium (LA) because of partial or complete absence of the CS roof. A 30-year-old woman was scheduled for surgical closure of atrial septal defect, mitral valve repair and tricuspid annuloplasty. The intraoperative transesophageal echocardiography (TEE) revealed left-to-right shunt between the CS and the LA. The three-dimensional (3D) TEE confirmed the diagnosis of partially URCS. This defect was repaired with a pericardial patch. In this case, the 3D images of URCS, which were a helpful supplement to the 2D images, providing better visualization of the wall defect and more information regarding the size and location of the defect. The combined use of 2D and 3D images provides valuable information to aid in understanding the anatomy and morphology of this rare anomaly.