Impact of Anesthetic and Ventilation Strategies on Invasive Hemodynamic Measurements in Pediatric Heart Transplant Recipients.

BACKGROUND: Care of pediatric heart transplant recipients relies upon serial invasive hemodynamic evaluation, generally performed under the artificial conditions created by anesthesia and supportive ventilation. OBJECTIVES: This study aimed to evaluate the hemodynamic impacts of different anesthetic and ventilatory strategies. METHODS: We compared retrospectively the cardiac index, right- and left-sided filling pressures, and pulmonary and systemic vascular resistances of all clinically well and rejection-free heart transplant recipients catheterized from 2005 through 2017. Effects of spontaneous versus positive pressure ventilation and of sedation versus general anesthesia were tested with generalized linear mixed models for repeated measures using robust sandwich estimators of the covariance matrices. Least squared means showed adjusted mean outcome values, controlled for appropriate confounders. RESULTS: 720 catheterizations from 101 recipients met inclusion criteria. Adjusted cardiac index was 3.14 L/min/m2 (95% CI 3.01-3.67) among spontaneously breathing and 2.71 L/min/m2 (95% CI 2.56-2.86) among ventilated recipients (p < 0.0001). With spontaneous breathing, left filling pressures were lower (9.9 vs 11.0 mmHg, p = 0.030) and systemic vascular resistances were higher (24.0 vs 20.5 Woods units, p < 0.0001). After isolating sedated from anesthetized spontaneously breathing patients, the observed differences in filling pressures and resistances emerged as a function of sedation versus general anesthesia rather than of spontaneous versus positive pressure ventilation. CONCLUSION: In pediatric heart transplant recipients, positive pressure ventilation reduces cardiac output but does not alter filling pressures or vascular resistances. Moderate sedation yields lower left filling pressures and higher systemic vascular resistances than does general anesthesia. Differences are quantitatively small.

The Effect of Repeated Versus Initial Procalcitonin Measurements on Diagnosis of Infection in the Intensive Care Setting: A Prospective Observational Study.

Procalcitonin (PCT) measurement has been proposed to direct antibiotic use. We examined whether repeated PCT measurements (0, 6, and/or 12 hours) versus the initial measurement only (time 0) increased the sensitivity and specificity of PCT for diagnosing infection in intensive care unit patients. Infection was identified in 67/176 (38%) patients. The sensitivity of repeated versus the initial PCT measurement (with a cutoff value 0.5 ng/mL) was 52/67 (77%; 95% confidence interval [CI], 66%-87%) vs 46/67 (69%; 95% CI, 56%-79%; P = .04) and specificity 60/109 (55%; 95% CI, 45%-65%) vs 59/109 (54%; 95% CI, 44%-64%; P = 1.0). Repeat PCT evaluations over 12 hours did not provide a clinically significant improvement in diagnostic accuracy when compared to the initial single test.

Blood cultures at central line insertion in the intensive care unit: comparison with peripheral venipuncture.

Blood cultures are a key diagnostic test for intensive care unit (ICU) patients; however, contaminants complicate interpretations and lead to unnecessary antibiotic administration and costs. Indications for blood cultures and central venous catheter (CVC) insertions often overlap for ICU patients. Obtaining blood cultures under the strict sterile precautions utilized for CVC insertion might be expected to decrease culture contamination. This retrospective study compared the results of blood cultures taken at CVC insertion, at arterial line insertion, and from peripheral venipuncture in order to validate the advantage of CVC insertion cultures. Cultures from indwelling lines were excluded. Results of 14,589 blood cultures, including 2,736 (19%) CVC, 1,513 (10%) arterial line, and 10,340 (71%) peripheral cultures taken over 5.5 years in two ICUs (general and medical) were analyzed. CVC cultures were contaminated more frequently than arterial line or peripheral cultures (225/2,736 [8%] CVC, 48/1,513 [3%] arterial line, and 378/10,340 (4%) peripheral cultures [P < 0.001 for CVC versus peripheral and CVC versus arterial line cultures]). True pathogens were found more frequently in CVC insertion cultures (334/2,736 [12%] CVC, 155/1,513 [10%] arterial line, and 795/10,340 [8%] peripheral cultures [P < 0.001 for CVC versus peripheral cultures; P = 0.055 for CVC versus arterial line cultures; P < 0.001 for peripheral versus arterial line cultures]). Contamination and true-positive rates were similar for culture sets from the two ICUs for each given culture source. Despite superior sterile precautions, cultures taken at the time of central line insertion had a higher contamination rate than did either peripheral or arterial line blood cultures. This may be related to the increased manipulations required for CVC insertion.

Impact of triage-to-admission time on patient outcome in European intensive care units: A prospective, multi-national study.

PURPOSE: Ubiquitous bed shortages lead to delays in intensive care unit (ICU) admissions worldwide. Assessing the impact of delayed admission must account for illness severity. This study examined both the relationship between triage-to-admission time and 28-day mortality and the impact of controlling for Simplified Acute Physiology Score (SAPS) II scores on that relationship. METHODS: Prospective cross-sectional analysis of referrals to eleven ICUs in seven European countries between 2003 and 2005. Outcomes among patients admitted within versus after 4 h were compared using a Chi-square test. Triage-to-admission time was also analyzed as a continuous variable; outcomes were assessed using a non-parametric Kruskal-Wallis test. RESULTS: Among 3175 patients analyzed, triage-to-admission time was 2.1 ±â€¯3.9 h. Patients admitted within 4 h had higher SAPS II scores (33.6 versus 30.6, Pearson correlation coefficient -0.07, p < 0.0001). 28-day mortality was surprisingly higher among patients admitted earlier (29.6 vs 25.2%, OR 1.25, 95% CI 0.99-1.58, p = 0.06). Even after adjusting for SAPS II scores, delayed admission was not associated with higher mortality (OR 1.08, CI 0.83-1.41, p = 0.58). CONCLUSIONS: Even after accounting for quantifiable parameters of illness severity, delayed admission did not negatively impact outcome. Triage practices likely influence outcomes. Severity scores may not fully reflect illness acuity or trajectory.

The common insertional polymorphism in the APOC1 promoter is associated with serum apolipoprotein C-I levels in Hispanic children.

We examined the effect of APOC1-317insCGTT allele status (HpaI RFLP, deletion [H1] and insertion [H2] alleles) on serum apolipoprotein (apo) C-I level in 362 Hispanic children in the Columbia University BioMarkers Study. The H2 allele was present in 147 subjects (40.6%). Serum apoC-I was 20% lower in the presence of the H2 allele in APOE epsilon3/epsilon3 homozygotes (P=0.003) but did not differ by H2 status in epsilon4 carriers. Insufficient numbers of epsilon2 carriers (N=45) were present for analysis. In multivariate analysis in the epsilon3/epsilon3 context, after adjusting for potential covariate effects and familial aggregation, the mean effect of H2/* versus H1/H1 on apoC-I level, was estimated to be 2.15+/-0.55mg/dl (P<0.0025). Plasma triglyceride level was weakly correlated with serum apoC-I level (Pearson's r=0.17, P<0.001) but was highly correlated with serum apoC-III (Pearson's r=0.74, P<0.0001). Nevertheless, presence of the H2 allele was not significantly associated with serum apoC-III level. Thus, the effect of APOC1 genotype on serum apoC-I level was not due to apoC-I level serving as a surrogate for triglyceride level. The APOC1-317insCGTT allele is a commonly polymorphic genetic marker that is associated with serum apoC-I level in the APOE epsilon3/epsilon3 context. These findings suggest that the mechanism of the previously described association with plasma TG is, at least in part, related to the correlation of the polymorphism with the level of expression of apoC-I.

Use of the nonwire central line hub to reduce blood culture contamination.

BACKGROUND: The sterile conditions used when inserting a central venous catheter (CVC) might be thought to decrease the contamination rate of blood cultures taken at CVC insertion; however, a previous retrospective study showed the opposite, that such blood cultures are contaminated more frequently than peripheral venipuncture blood cultures. The current study explored whether use of the CVC nonwire hub as a source of blood cultures decreased contamination while maintaining detection of true pathogens. METHODS: A prospective, observational study was performed from June 2010 to May 2011 in the general ICU of an academic, tertiary referral center. The proportions of blood cultures taken from wire and nonwire CVC hubs growing contaminants and true pathogens were compared. Risk factors for blood culture contamination were identified, and multivariate analysis was used to identify independent predictors of blood culture contamination. RESULTS: Among 313 blood cultures taken from 227 CVCs in 139 patients, 27 of 141 wire hub (19%) vs nine of 172 nonwire hub (5%) cultures were contaminated (P < .001). Only hub of blood culture origin was associated with contamination on multivariate analysis (OR, 4.3; 95% CI, 1.9-9.5; P < .001). True pathogens grew in 19 of 141 wire hub (13%) vs 27 of 172 nonwire hub (16%) cultures (P = .581). CONCLUSIONS: A higher proportion of blood cultures taken from the CVC lumen exposed to the guidewire were contaminated when compared with nonwire hub cultures; detection of true pathogens was equivalent. To limit detrimental sequelae of blood culture contamination, blood cultures obtained at CVC insertion should be taken from the nonwire hub.