Robert H. Riffenburgh

Non-ampullary duodenal adenocarcinoma: Factors important for relapse and survival

Duodenal adenocarcinoma (DA) is rare, but potentially curable. Prospective data on treatment outcomes is scarce and large retrospective studies show conflicting results on the impact of radical resection, node‐status, and adjuvant therapy.

B-type Natriuretic Peptide: Perioperative Patterns in Congenital Heart Disease

OBJECTIVEnB-type natriuretic peptide (BNP) has diagnostic, prognostic, and therapeutic roles in adults with heart failure. BNP levels in children undergoing surgical repair of congenital heart disease (CHD) were characterized broadly, and distinguishable subgroup patterns delineated.nnnDESIGNnProspective, blinded, observational case series.nnnSETTINGnAcademic, tertiary care, free-standing pediatric hospital.nnnPATIENTSnChildren with CHD; controls without cardiopulmonary disease. Interventions. None.nnnMEASUREMENTSnPreoperative cardiac medications/doses, CHD lesion types, perioperative BNP levels, intraoperative variables (lengths of surgery, bypass, cross-clamp), postoperative outcomes (lengths of ventilation, hospitalization, open chest; averages of inotropic support, central venous pressure, perfusion, urine output; death, low cardiac output syndrome (LCOS), cardiac arrest; readmission; and discharge medications).nnnRESULTSnMedian BNP levels for 102 neonatal and non-neonatal controls were 27 and 7 pg/mL, respectively. Serial BNP measures from 105 patients undergoing CHD repair demonstrated a median postoperative peak at 12 hours. The median and interquartile postoperative 24-hour average BNP levels for neonates were 1506 (782-3784) pg/mL vs. 286 (169-578) pg/mL for non-neonates (P < 0.001). Postoperative BNP correlated with inotropic requirement, durations of open chest, ventilation, intensive care unit stay, and hospitalization (r = 0.33-0.65, all P < 0.001). Compared with biventricular CHD, Fontan palliations demonstrated lower postoperative BNP (median 150 vs. 306 pg/mL, P < 0.001), a 3-fold higher incidence of LCOS (P < 0.01), and longer length of hospitalization (median 6.0 vs. 4.5 days, P= 0.01).nnnCONCLUSIONSnPerioperative BNP correlates to severity of illness and lengths of therapy in the CHD population, overall. Substantial variation in BNP across time as well as within and between CHD lesions limits its practical utility as an isolated point-of-care measure. BNP commonly peaks 6-12 hours postoperatively, but the timing and magnitude of BNP elevation demonstrates notable age-dependency, peaking earlier and rising an order of magnitude higher in neonates. In spite of higher clinical acuity, non-neonatal univentricular CHD paradoxically demonstrates lower BNP levels compared with biventricular physiologies.

Bedside Method to Estimate Actual Body Weight in the Emergency Department

BACKGROUNDnActual body weight (ABW) is important for accurate drug dosing in emergency settings. Oftentimes, patients are unable to stand to be weighed accurately or clearly state their most recent weight.nnnOBJECTIVEnDevelop a bedside method to estimate ABW using simple anthropometric measurements.nnnMETHODSnProspective, blinded, cross-sectional convenience sampling of adult Emergency Department (ED) patients. A multiple linear regression equation from Derivation Phase (n = 208: 121 males, 87 females) found abdominal and thigh circumferences (AC and TC) had the best fit and an inter-rater correlation of 0.99 and 0.96, respectively: Male ABW (kg) = -47.8 + 0.78 ∗ (AC) + 1.06 ∗ (TC); Female ABW = -40.2 + 0.47 ∗ (AC) + 1.30 ∗ (TC).nnnRESULTSnDerivation phase: Number of patients (%) with a body weight estimation (BWE) > 10 kg from ABW for males/females were: 7 (6%)/1 (1%) for Patients, 46 (38%)/28 (32%) for Doctors, 38 (31%)/24 (27%) for Nurses, 75 (62%)/43 (49%) for 70 kg/60 kg convention, and 14 (12%)/8 (9%) using the anthropometric regression model. For validation phase (55 males, 44 females): Gold standard ABW mean (SD) male/female = 83.6 kg (14.3)/71.5 kg (18.9) vs. anthropometric regression model = 86.3 kg (14.7)/73.3 kg (15.1). R(2) = 0.89, p < 0.001. The number (%) for males/females with a BWE > 10 kg using the anthropometric regression model = 8 (15%)/11 (27%).nnnCONCLUSIONSnFor male patients, a regression model using supine thigh and abdominal circumference measurements seems to provide a useful and more accurate alternative toxa0physician, nurse, or standard 70-kg male conventional estimates, but was less accurate for use in female patients.

Bedside estimation of patient height for calculating ideal body weight in the emergency department.

BACKGROUNDnIdeal body weight (IBW), which can be calculated using the variables of true height and sex, is important for drug dosing and ventilator settings. True height often cannot be measured in the emergency department (ED).nnnOBJECTIVESnDetermine the most accurate method to estimate IBW using true height-based IBW that uses true height estimated by providers or patients compared to true height estimated by a regression formula using measured tibial length, and compare all to the conventional 70 kg male/60 kg female standard IBW.nnnMETHODSnProspective, observational, double-blind, convenience sampling of stable adult patients in a tertiary care ED from September 2004 to April 2006. Derivation set (215 patients) had blinded provider and patient true height estimates and tibial length measurements compared to gold-standard standing true height. A validation set (102 patients) then compared the accuracy of IBW using true height calculated from the regression formula vs. IBW using gold-standard true height. Regression formula for men tibial length-IBW (kg) = 25.83 + 1.11 × tibial length; for women tibial length-IBW = 7.90 + 1.20 × tibial length; R(2) = 0.89, p < 0.001. Inter-rater correlation of tibial length was 0.94.nnnRESULTSnDerivation set: percent within 5 kg of true height-based IBW for men/women =nnnPATIENTn91.1%:/85.7%; Physician: 66.1%/45.1%; Nurse: 65.7%/ 47.3%; tibial length: 66.1%/63.7%; and 70 kg male/60 kg female standard 46%/75%. Validation set: tibial length-IBW estimates were within 5 kg of true height-ideal body weight in only 56.2% of men and 42.2% of women.nnnCONCLUSIONSnPATIENT-reported height is the best bedside method to estimate true height to calculate ideal body weight. Physician and nurse estimates of true height are substantially less accurate, as is true height obtained from a regression formula that uses measured tibial length. All methods were more accurate than using the conventional 70 kg male/60 kg female IBW standard.

Regime Testimation in a Time Sequence

Two years of irregularly spaced measurements of seawater temperature at 200 feet at a fixed North Pacific Ocean location are considered. The data are heteroscedastic in time and the average path jumps about erratically. We seek points of significant change in the data-generating process and wish to study their nature. The set of all properties characterizing a data-generating process is its regime. Simultaneous testing and estimation is testimation. We must testimate abrupt changes in the regime as a whole instead of property by property. A moving mean square of error values is posed as a statistic and its relation to x 2 and F derived. Methods of testimation and decomposition of the statistic into proportions due to each possible cause are obtained. The pattern of behavior of the statistic which identifies an outlier is considered. It is possible for two properties in the regime to change jointly such that one change obscures the other. Methods to detect and solve this problem are derived. The temperatur...

Contrast-Enhanced MRI Evaluation of Bone-Patellar Tendon-Bone and Hamstring ACL Autograft Healing in Humans: A Prospective Randomized Study.

Background: Gadopentetate dimeglumine–enhanced magnetic resonance imaging (MRI), or gadolinium-enhanced MRI, was used to prospectively study the postoperative course of bone–patellar tendon–bone (BPTB) and combined semitendinosus and gracilis (STG) tendon autografts following arthroscopically assisted reconstruction of the anterior cruciate ligament (ACL) in humans. Gadopentetate dimeglumine is a contrast agent that has been shown to enhance the signal of vascularized tissue when examined by MRI. Purpose: To prospectively determine and compare the pattern and timing of autograft revascularization following arthroscopically assisted ACL reconstruction by BPTB or STG autografts. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 73 patients (63 males, 10 females) with ACL tears who were scheduled to undergo reconstruction consented to participate in this study. The patients were randomized to receive arthroscopically assisted reconstruction of the ACL employing either BPTB or STG autografts. Gadolinium-enhanced MRI scans were scheduled at 3-month intervals during the first postoperative year to assess the integrity, timing, and pattern of enhancement of the ACL graft. The temporal sequence and morphologic characteristics of imaged signals were compared for both types of ACL reconstructions. Results: Based on all knees with 1 exception, there were no statistically significant differences in gadopentetate dimeglumine–mediated graft enhancement grade observed between BPTB and STG autografts. Conclusion: The results suggest that autograft revascularization probably varies in intensity and location during the time course of graft healing. The interval signal changes observed 3 to 9 months, but especially 6 to 9 months, postoperatively are due to increased contrast uptake as a reflection of ongoing neovascularization during the process of ligamentization.