The stop-flow arm equilibrium pressure in preoperative patients: Stressed volume and correlations with echocardiography.

BACKGROUND: The distending intravascular pressure at no flow conditions reflects the stressed volume. While this haemodynamic variable is recognised as clinically important, there is a paucity of reports of its range and responsiveness to volume expansion in patients without cardiovascular disease and no reports of correlations to echocardiographic assessments of left ventricular filling. METHODS: Twenty-seven awake (13 male), spontaneously breathing patients without any history of cardiopulmonary, vascular or renal disease were studied prior to induction of anaesthesia. The no-flow equilibrium pressure in the arm following rapid circulatory occlusion (Parm ) was measured via a radial arterial catheter. Transthoracic echocardiography was used to measure left ventricular end diastolic area and volume as well as the diameter of the inferior vena cava. The Parm and echocardiographic variables were measured before and after administration of 500 mL 0.9% NaCl over 10 minutes. Changes were analysed by paired t test, Pearson's correlation and multiple linear regression. RESULTS: Parm increased overall from 22 ± 5 mm Hg to 25 ± 6 mm Hg (mean difference 3.0 ± 4.5 mm Hg, P = 0.002) following the fluid bolus with corresponding increases in arterial pressure and echocardiographic variables. Variability in the direction of the Parm response reflected concomitant changes in vascular compliance. Only weak correlations were observed between changes in Parm and inferior vena cava diameter indexed to body surface area (R2  = 0.29, P = 0.01). CONCLUSION: Preoperative measurements of Parm increased following acute expansion of the intravascular volume. Echocardiography demonstrated poor correlation with Parm .

Stereotactic radiosurgery and hypofractionated stereotactic radiotherapy for management of vestibular schwannomas: initial experience with 17 cases.

BACKGROUND: Nowadays radiation treatment of patients with vestibular schwannomas (VSs) applied either as stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) represents a real alternative to surgical tumor resection. METHODS: During 2010-2011, 17 consecutive patients (19-75 years old) with a VS underwent treatment with SRS or SRT in our center. Microsurgery was initially offered in all cases but was declined for various reasons. Five lesions recurred after the initial partial resection. Two other patients with neurofibromatosis type 2 underwent initial surgery for a large tumor on the contralateral side and had the only hearing ear on the side of the remaining neoplasm. Three elderly persons had somatic problems that were too severe for them to undergo craniotomy. Five small tumors without brain stem compression underwent single-fraction SRS (12.0-12.5 Gy at the 80 % isodose line). Other patients, mainly with large neoplasms that caused brain stem compression, were treated with hypofractionated SRT (five or six daily fractions at a dose of 4.5-5.0 Gy each). Treatment was performed with a dedicated linear accelerator (Elekta Axesse). Various stereotactic fixation devices were used: Leksell G frame, noninvasive HeadFIX frame, reinforced thermoplastic masks. RESULTS: No adverse reactions or complications were seen in any case. Within 3 months after treatment three tumors demonstrated shrinkage accompanied by improvement of the neurological functions. CONCLUSION: Radiation treatment, particularly hypofractionated SRT, can be safely applied even for large VSs that cause brain stem compression and are accompanied by prominent neurological symptoms.