Blood volume measured by ultrasound and radioisotope dilution in critically ill subjects.

BACKGROUND: Accurate bedside assessment of circulating blood volume (BV) continues to challenge clinicians in their attempt to implement goal-directed therapy in the critically ill subject. The aim of this investigation was to comparatively evaluate BV measurements obtained by ultrasound and radioisotope dilution methodologies in adult subjects admitted to a surgical intensive care unit. MATERIALS AND METHODS: Fifty subjects with concurrent central venous catheters and peripheral arterial lines underwent measurement of BV using both ultrasound and radioisotope dilution (BV-RD) methods. The ultrasound dilution method was performed using a 30-mL injectate (BV-UD30) and a 60-mL injectate (BV-UD60) of isotonic saline. RESULTS: There were 24 paired data points for the BV-UD30 and 40 paired data points for the BV-UD60 measurements. Spearman's rank-order correlation demonstrated a positive relationship comparing both the BV-UD30 (r = 0.46, P = 0.0249) and the BV-UD60 (r = 0.80, P < 0.0001) to values obtained by radioisotope measurements. Bland-Altman analysis showed a mean bias of 1329 mL with limits of agreement (LOA) ± 2559 mL comparing BV-RD and BV-UD30, and a mean bias of 62 mL with LOA ±1353 mL for BV-RD and BV-UD60. CONCLUSIONS: This preliminary investigation shows that the BV-UD60 had better agreement with BV-RD, compared with the BV-UD30, but its utility appears limited by a large LOA. As this technology continues to evolve, the ultrasound dilution approach may potentially become a feasible means to calculate BV in critically ill surgical subjects.

Brain-type natriuretic peptide and right ventricular end-diastolic volume index measurements are imprecise estimates of circulating blood volume in critically ill subjects.

BACKGROUND: Surrogate indicators have often been used to estimate intravascular volume to guide fluid management. Brain-type natriuretic peptide (BNP) has been used as a noninvasive adjunct in the diagnosis of fluid overload and as a marker of response to therapy, especially in individuals with congestive heart failure. Similarly, right ventricular end-diastolic volume index (RVEDVI) measurements represent another parameter used to guide fluid resuscitation. The aim of this study was to evaluate whether BNP and RVEDVI are clinically valuable parameters that can distinguish among hypovolemia, euvolemia, and hypervolemia, as measured by blood volume (BV) analysis in critically ill surgical subjects. METHODS: This observational study was part of a prospective, randomized controlled trial. Subjects with pulmonary artery catheters for the treatment of traumatic injuries, severe sepsis/septic shock, cardiovascular collapse, adult respiratory distress syndrome, and postsurgical care were studied. Circulating BV was measured by a radioisotope dilution technique using the BVA-100 Analyzer (Daxor Corporation, New York, NY) within the first 24 hours of acute resuscitation. BV results were reported as percent deviation from the patient's ideal BV based on height and percent deviation from optimum weight. Hypovolemia was defined as less than 0%, euvolemia was defined as 0% to +16%, and hypervolemia was defined as greater than +16% deviation from ideal BV. RVEDVI was measured by continuous cardiac output pulmonary artery catheters (Edwards Lifesciences, Irvine, CA). BNP and RVEDVI measurements obtained with BV analysis were evaluated with Fisher's exact test and regression analysis. RESULTS: In 81 subjects, there was no difference in BV status between those with BNP of 500 pg/mL or greater and BNP of less than 500 pg/mL (p = 0.82) or in those with RVEDVI of 140 mL/m or greater and RVEDVI of less than 140 mL/m (p = 0.43). No linear relationship existed between BV and these parameters. CONCLUSION: In critically ill surgical patients, BNP and RVEDVI were not associated with intravascular volume status, although they may be useful as indices that reflect increased cardiac preload. LEVEL OF EVIDENCE: Diagnostic study, level III.

Effect of the 16-hour work limit on general surgery intern operative case volume: a multi-institutional study.

IMPORTANCE: The 80-hour work-week limit for all residents was instituted in 2003 and studies looking at its effect have been mixed. Since the advent of the 16-hour mandate for postgraduate year 1 residents in July 2011, no data have been published regarding the effect of this additional work-hour restriction. OBJECTIVE: To determine whether the 16-hour intern work limit, implemented in July 2011, has adversely affected operative experience. DESIGN, SETTING, AND PARTICIPANTS: A retrospective review of categorical postgraduate year 1 Accreditation Council for Graduate Medical Education case logs from the intern class (N = 52) (with 16-hour work limit) compared with the 4 preceding years (2007-2010; N = 197) (without 16-hour work limit). A total of 249 categorical general surgery interns from 10 general surgery residency programs in the western United States were included. MAIN OUTCOMES AND MEASURES: Total, major, first-assistant, and defined-category case totals. RESULTS: As compared with the preceding 4 years, the 2011-2012 interns recorded a 25.8% decrease in total operative cases (65.9 vs 88.8, P = .005), a 31.8% decrease in major cases (54.9 vs 80.5, P < .001), and a 46.3% decrease in first-assistant cases (11.1 vs 20.7, P = .008). There were statistically significant decreases in cases within the defined categories of abdomen, endocrine, head and neck, basic laparoscopy, complex laparoscopy, pediatrics, thoracic, and soft tissue/breast surgery in the 16-hour shift intern era, whereas there was no decrease in trauma, vascular, alimentary, endoscopy, liver, and pancreas cases. CONCLUSIONS AND RELEVANCE: The 16-hour work limit for interns, implemented in July 2011, is associated with a significant decrease in categorical intern operative experience. If the 16-hour shift were to be extended to all postgraduate year levels, one can anticipate that additional years of training will be needed to maintain the same operative volume.

The availability of circulating blood volume values alters fluid management in critically ill surgical patients.

BACKGROUND: This study evaluated whether commercially available blood volume measurements in critically ill surgical patients altered fluid management. METHODS: Patients admitted to the surgical intensive care unit of a tertiary care teaching hospital were prospectively evaluated. The frequency of changes in fluid management when results of blood volume measurements were available was determined. RESULTS: In a pilot study, the frequency of instances when measurement of blood volume would have altered fluid management was statistically significant (P = .0003). In 40 subsequent patients, treatment change occurred in 36% of instances when blood volume results were obtained (P < .001). In the majority, no immediate qualitative change in clinical status occurred, with a desirable clinical response in 39% and no negative treatment responses (P < .001). CONCLUSIONS: Blood volume measurements may assist in the management of critically ill surgical patients by providing a direct measure of intravascular volume. Further studies are warranted to determine its effect on outcome.

Twenty-eight-day mortality in critically ill surgical patients is an imprecise temporal end-point measure for in-hospital mortality.

BACKGROUND: The purpose of this study was to determine the incidence of deaths occurring beyond 28 days in critically ill surgical patients and to identify the proportion of these deaths attributable to the original disease process. METHODS: Analysis of 1,360 subjects admitted to a surgical intensive care unit during a 2 year period. Demographics, indication(s) for admission, comorbidities, mortality rate, multiorgan failure development, and cause of death was obtained. RESULTS: Mortality rate in the surgical intensive care unit was 12%. Twenty % of deaths occurred more than 28 days after hospital admission with 76% of deaths related to admission diagnosis. By day 34, 95% of mortalities had occurred. CONCLUSIONS: The 28-day time period used to assess efficacy of therapeutic interventions and to define mortality in the context of quality audits should be questioned. If these findings are validated in other centers another temporal end point for in-hospital mortality should be considered.

Determination of reference ranges for transcutaneous oxygen and carbon dioxide tension and the oxygen challenge test in healthy and morbidly obese subjects.

BACKGROUND: Transcutaneous monitoring of oxygen and carbon dioxide tension emerged decades ago as reliable, indirect measurements of arterial pressure of oxygen and carbon dioxide in neonates. Investigators have since found other valuable roles for this modality, particularly in critically ill adults. This investigation was undertaken to further characterize these measurements in normal and in obese adults, who are contributing to a rising proportion of intensive care unit admissions. MATERIALS AND METHODS: Transcutaneous sensors were adjusted for barometric pressure and calibrated to reference gases. The following were measured: equilibration time; oxygen saturation; transcutaneous oxygen tension; and transcutaneous carbon dioxide tension on room air and after administering fraction of inspired oxygen of 1.0 for 5 min (Oxygen Challenge Test). RESULTS: One hundred three healthy and 47 obese subjects were enrolled. Oxygen Challenge Test values were 131.5 +/- 57.4 and 171.6 +/- 65.9 mm Hg for obese and healthy subjects, respectively (P value <0.001). Smoking status, respiratory rate, and transcutaneous oxygen tension on room air best predicted the Oxygen Challenge Test response. A negative correlation was found between transcutaneous oxygen on room air and the Oxygen Challenge Test versus body mass index (P < 0.001). CONCLUSIONS: Reference ranges were determined for transcutaneous oxygen and carbon dioxide tension and the Oxygen Challenge Test in obese and in normal, healthy subjects. Increasing body mass index was associated with a lower baseline transcutaneous oxygen tension, but it was not an independent predictor of the Oxygen Challenge Test response in multivariate analysis.

Other primary neoplasms in patients with hepatocellular cancer: prognostic implications?

PURPOSE: Little is known about other primary neoplasms occurring in patients with hepatocellular cancer (HCC). This team attempted to characterize this cohort of patients to define incidence, risk factors, natural history, and potentially shared etiologies. METHODS: A retrospective analysis from an established, prospective database of patients with HCC during 1991-2004 was used to determine demographic data, risk factors, characteristics of the associated second primary neoplasm, and survival. MAIN FINDINGS: Of 306 patients with HCC, 23 patients (7.5%) were identified with a second neoplasm. Two of these patients had a third neoplasm. Mean age was 65.6 years and male:female ratio was 2.3:1. Risk factors included: hepatitis B (27.3%), hepatitis C (40.9%), smoking (17.4 %), diabetes (26.1%), cirrhosis (63.6%), and family history of HCC (4.5%). Second associated primaries included 7 genitourinary (prostate--2, bladder--2, testicular--1, renal--1, ovarian--1), 7 gastrointestinal (colon--6, gastric--1), 3 breast, 2 skin, 2 lung, 2 hematologic, 1 tongue, and 1 desmoid. Four patients had HCC first, 1 patient had synchronous HCC and colon cancer, while 18 had the other primary first. Mean, 1 and 2-year survival after diagnosis of HCC was 1014.8 days, 75%, and 30%, compared to 782.6 days, 54.6%, and 41.1%, respectively, in the group with HCC only (p > 0.05). CONCLUSION: The incidence of other primary tumors in the setting of HCC is relatively common with a strong clustering of genitourinary and gastrointestinal malignancies. There was no statistically significant difference in overall survival compared to patients with HCC only, suggesting that the association of other primary tumors with HCC does not confer a worse prognosis.

The Cancer of the Liver Italian Program (CLIP) score: validation of a new prognostic system for hepatocellular carcinoma.

PURPOSE: To determine the prognostic validity of a new staging system for hepatocellular carcinoma (HCC) proposed by the Cancer of the Liver Italian Program (CLIP) in the context of existing staging systems of known significance. METHODS: Retrospective analysis from an established prospective database of patients with HCC treated at a single, University-affiliated, community-based, tertiary center All consecutively referred patients between 1991 and 2002 were eligible. Duration of follow up was 4 months to 11 years. CLIP score, Okuda, and American Joint Commission on Cancer Stage were determined for each case. Overall survival was the main endpoint measure. MAIN FINDINGS: Of 208 eligible patients, 8 were excluded due to lack of complete data necessary to determine CLIP Okuda, and AJCC stage parameters. All three prognostication systems individually were predictive of overall survival. Logistic regression analysis demonstrated that AJCC staging was the best prognostic discriminator; however, when CLIP scores 3 through 6 were combined due to small sample size, the CLIP score was found to be the best index of prognosis. CONCLUSION: The CLIP score may provide a more precise, quantitative method for improved prognostication of patients with HCC.