Effects of prone and reverse trendelenburg positioning on ocular parameters.

BACKGROUND: : In a pilot study of awake volunteers, intraocular pressure (IOP), choroid layer thickness, and optic nerve diameter were shown to increase in the prone position over 5 h with a nonsignificant trend of attenuation using a 4-degree increase of table inclination. These effects have previously not been isolated from anesthetic and fluid administration over a prolonged period, using an adequate sample size. METHODS: : After institutional review board approval, 10 healthy volunteers underwent IOP measurement (Tono-Pen XL, Medtronic Solan, Jacksonville, FL) as well as choroidal thickness and optic nerve diameter assessment (Sonomed B-1000, Sonomed, Inc., Lake Success, NY, or the I System-ABD, Innovative Imaging, Inc., Sacramento, CA) on a Jackson table (Orthopedic Systems, Inc., Union City, CA), during 5 h horizontal prone and 5 h 4-degree reverse Trendelenburg positioning. Measurements were assessed as initial supine, initial prone, and hourly thereafter. Vital signs were recorded at each position and time point. RESULTS: : IOP, choroidal thickness, and optic nerve diameter were observed to increase with time in the prone position. A small degree of reverse Trendelenburg attenuated the increase in choroidal thickness but not IOP or optic nerve diameter. CONCLUSIONS: : Prolonged prone positioning increases IOP, choroid layer thickness, and optic nerve diameter independent of anesthetics and intravenous fluid infusion and 4 degrees of table inclination (15 cm of head to foot vertical disparity) may not attenuate these effects.

Pulmonary artery flow patterns after the Fontan procedure are predictive of postoperative complications.

OBJECTIVE: Pulmonary artery (PA) flow reversal has been associated with poor outcome in patients with atriopulmonary (APC) and total cavopulmonary connection (TCPC) lateral tunnel (LT) Fontan modification. The authors studied PA flow after TCPC in relation to the incidence of early Fontan outcome and complications. DESIGN: A prospective observational study. SETTING: A university hospital. PARTICIPANTS: Pediatric patients undergoing a Fontan procedure. INTERVENTION: Nineteen patients were studied. PA flow was measured by pulse-wave Doppler during the surgery after chest closure. Patients were divided into 2 groups according to patterns of PA flow: group 1, positive (biphasic or continuous flow), and group 2, negative (with flow reversal component). The postoperative complications were recorded. MEASUREMENTS AND MAIN RESULTS: There were no deaths or reoperations for Fontan takedown. Ten patients had positive and 9 had negative flow. There were no differences between groups regarding age, weight, length of procedure, and cardiopulmonary bypass. The chest tube drainage in patients with negative flow was significantly longer than those in the positive-flow group (8.3 +/- 7.0 days in the negative-flow group v 2.8 +/- 1.7 days in the positive-flow group, p = 0.03). The total number of complications was higher in the negative-flow group compared with the positive-flow group (3.0 +/- 1.3 v 1.2 +/- 0.6, p = 0.003). The differences between groups in terms of pediatric intensive care unit and/or hospital length of stay did not reach statistical significance, possibly because of the low number of patients. CONCLUSION: PA flow pattern appears to be predictive of the length of postoperative chest tube drainage and the number of postoperative complications.

Geographic regional differences in rocuronium bromide dose-response relation and time course of action: an overlooked factor in determining recommended dosage.

BACKGROUND: Geographic location is not acknowledged as a stratifying factor that can directly affect drug potency, because drugs are still licensed with the same recommended dose for different geographic regions. The aim of the current study was to compare the potency and duration of action of rocuronium bromide in 54 patients in three countries with different life habits, diet, and ambient conditions, namely white Austrians, white North Americans, and Han Chinese in China. METHODS: Neuromuscular block of six consecutive 50-microg/kg rocuronium incremental doses followed by 300 microg/kg was evaluated using the Relaxometer mechanomyograph (Groningen University, Groningen, Holland). Dose-response curves were created using log-dose-probit transformation. The authors compared rocuronium bromide ED50, ED90, and ED95 (effective doses required for 50%, 90%, and 95% first twitch depression, respectively) as well as Dur25 and Dur0.8 (times from last incremental dose administration until 25% first twitch and 0.8 train-of-four ratio recovery, respectively) in patients of the three countries. RESULTS: Rocuronium ED50, ED90, and ED95 were significantly higher in Austrian patients (258 +/- 68, 530 +/- 159, and 598 +/- 189 microg/kg) and Chinese patients (201 +/- 59, 413 +/- 107, and 475 +/- 155 microg/kg) compared with American patients (148 +/- 48, 316 +/- 116, and 362 +/- 149 microg/kg, respectively). Dur25 and Dur0.8 were significantly shorter in Austrian patients (22.3 +/- 5.5 and 36.9 +/- 12.8 min) and Chinese patients (30.4 +/- 7.5 and 45.7 +/- 15.9 min) compared with American patients (36.7 +/- 8.5 and 56.2 +/- 16.7 min, respectively). CONCLUSIONS: The authors demonstrated a significant difference in rocuronium potency and duration of action among patients in the three countries. Larger studies are required for determining dosage recommendations for different geographic regions.

Multidisciplinary management of a Jehovah's Witness patient for the removal of a renal cell carcinoma extending into the right atrium.

PURPOSE: To highlight the management of a Jehovah's witness surgical patient presenting for cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest. CLINICAL FEATURES: A 47-yr-old male, Jehovah's Witness, with renal cell carcinoma was admitted for left radical nephrectomy and excision of tumour thrombus extending into the junction of the inferior vena cava (IVC) and right atrium (RA). The preoperative goals were to maximize red blood cell mass, delineate the extent of tumour extension and develop a surgical plan incorporating blood conservation strategies to minimize blood loss. A midline abdominal incision was made to optimize removal of the non-caval portion of the tumour from the intra-abdominal region. CPB and deep hypothermic circulatory arrest were instituted to aid in removing the tumour from the IVC and RA. Intraoperative blood conservation strategies included the use of acute normovolemic hemodilution, antifibrinolytics, cell salvage, point-of-care monitoring of heparin and protamine blood concentrations, leukocyte-depleting filter, and meticulous surgical techniques. The patient was successfully weaned from CPB and was transported to the cardiothoracic intensive care unit without complication. The patient was discharged home one week after the operation with a hemoglobin of 10.2 g x dL(-1) and a hematocrit of 31.2%. CONCLUSION: Multiple blood conservation techniques were employed to manage this Jehovah's Witness patient through complex cardiac surgery, which was previously denied to him at other institutions. The successful outcome of this patient, while respecting the right to refuse allogeneic blood products, is a result of a multidisciplinary collaboration as well as the application of established blood conservation techniques.