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.

Delayed Respiratory Failure After Blunt Chest Trauma.

BACKGROUND: Patient factors associated with delayed respiratory failure (DRF) after blunt chest trauma are not well documented. Earlier identification and closer monitoring may improve outcomes for these patients. The purpose of this study was to identify the prevalence and clinical predictors of DRF in patients after blunt chest trauma. MATERIALS AND METHODS: A retrospective review of adult patients admitted to a Level 1 trauma center after blunt chest trauma between January 1, 2009 and December 31, 2013, was conducted. Patients with early respiratory failure were compared to patients with DRF using Fisher's exact tests, chi square, and Student's t-tests. A P-value of <.05 was considered significant. RESULTS: 1299 patients had blunt chest trauma and at least 1 rib fracture, of which 830 met inclusion criteria. 5.8% of patients progressed to respiratory failure. Respiratory failure was delayed in 25% of these patients. DRF patients had significantly lower ISS (16.5 vs. 22.7, P = .04), more bilateral rib fractures (66.7% vs. 28.7%, P = .02) and fewer pulmonary contusions (16.7% vs. 50.0%, P = .04). DISCUSSION: Injury patterns, including bilateral rib fractures without pulmonary contusions and low but severe Injury Severity Score burden, may help identify high-risk patients who may benefit from closer monitoring and more aggressive therapy.

Fatal postoperative arrhythmia in a man with a remote history of methamphetamine and cocaine use: a case report.

Long-term methamphetamine and cocaine use are associated with significant cardiovascular consequences. Despite these demonstrated associations, adverse effects that persist after cessation of drug use are difficult to establish. Cardiovascular pathology associated with long-term drug use may have subclinical presentations that persist long after cessation of drug use. In asymptomatic persons with a remote history of long-term methamphetamine or cocaine use, it may be prudent to assume existing subclinical cardiovascular pathology with positive methamphetamine or cocaine use history as a cardiac risk factor.

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.

Methamphetamine use in deceased kidney donors impairs one-yr graft function.

BACKGROUND: Methamphetamine (MA) has cumulative deleterious effects on multiple organ systems. A history of MA exposure in kidney donors may affect adversely graft function in recipients. METHODS: Between September 2000 and March 2004, all deceased kidney donors were identified from the local registry (97 donors). Twenty donors (21%) with any MA exposure through history or toxicology were selected. Donors that did not fulfill UNOS standard criteria were excluded. Donor characteristics and subsequent recipient characteristics were retrospectively compared with a control group without MA exposure histories. The main outcome measure was mean serum creatinine at one-yr post-transplant (Cr365). Secondary outcome measures of delayed graft function and rejection episodes were reviewed. RESULTS: Baseline serum creatinine at seven d post-transplant were equivalent between groups (Cr7 = 2.5 +/- 2.0 vs. 2.8 +/- 3.4, p = 0.75). At one yr, Cr365 was significantly elevated in recipients of MA exposed kidneys compared with controls (1.9 +/- 1.0 vs. 1.4 +/- 0.4, p = 0.028). When adjusted for confounding variables, MA exposure lost its statistical significance (p = 0.07-0.09) as an independent predictor of increased Cr365. CONCLUSION: Donor MA exposure may be associated with increased Cr365 in recipients. Transplant centers can expect to encounter donors with MA use histories at rates higher that regional use rates. Larger studies may demonstrate MA exposure as an independent predictor of impaired graft function.