Clinical use of continuous arterial blood gas monitoring in the pediatric intensive care unit

CONTEXT: Continuous arterial blood gas monitoring is a new technology based on the combination of opto-chemical and fiber-optic detectors that can measure pH, PCO2, PO2, and temperature on a continuous basis via a sensor placed in an artery. OBJECTIVE: To evaluate this technology in pediatric patients who would normally require frequent arterial blood gas sampling. DESIGN: A criterion standard study in which the results of arterial blood gas samples measured by the laboratory analyzer were compared with the sensor readings. SETTING: A pediatric intensive care unit of a tertiary referral center. PATIENTS: Children with severe respiratory failure who required frequent arterial blood gas sampling and who had a 20-gauge arterial line in either a radial or femoral site. RESULTS: Twenty-four patients with a mean age of 6.4 years (range 1-21 years) had a sensor placed. Sensors were in place for a mean of 101 +/- 62 hours. Eighteen patients underwent continuous monitoring for at least 24 hours or until no longer clinically necessary. There were 414 pairs of blood gas samples obtained. The bias/precision for pH was 0.005/0.030; for PCO2, -1.8/6.3 mm Hg; and for PO2, 1.2/24 mm Hg. The correlation (r value) between the sensor readings and the blood gases were pH 0. 960, PCO2 0.927, PO2 0.813 (P <.01 for all values). The bias and precision for PO2 levels < 70 mm Hg were 0.057/9.34 mm Hg. There were no complications from sensor placement. Continuous blood gas monitoring allowed immediate recognition of clinical changes. CONCLUSION: The continuous arterial blood gas sensor is capable of clinically accurate blood gas measurements. This technology provides the clinician with immediate data that can allow rapid interventions in unstable patients.     

Measurement of myocardial blood flow by cardiovascular magnetic resonance perfusion: comparison of distributed parameter and Fermi models with single and dual bolus

Background

Mathematical modeling of cardiovascular magnetic resonance perfusion data allows absolute quantification of myocardial blood flow. Saturation of left ventricle signal during standard contrast administration can compromise the input function used when applying these models. This saturation effect is evident during application of standard Fermi models in single bolus perfusion data. Dual bolus injection protocols have been suggested to eliminate saturation but are much less practical in the clinical setting. The distributed parameter model can also be used for absolute quantification but has not been applied in patients with coronary artery disease. We assessed whether distributed parameter modeling might be less dependent on arterial input function saturation than Fermi modeling in healthy volunteers. We validated the accuracy of each model in detecting reduced myocardial blood flow in stenotic vessels versus gold-standard invasive methods.

Methods

Eight healthy subjects were scanned using a dual bolus cardiac perfusion protocol at 3T. We performed both single and dual bolus analysis of these data using the distributed parameter and Fermi models. For the dual bolus analysis, a scaled pre-bolus arterial input function was used. In single bolus analysis, the arterial input function was extracted from the main bolus. We also performed analysis using both models of single bolus data obtained from five patients with coronary artery disease and findings were compared against independent invasive coronary angiography and fractional flow reserve. Statistical significance was defined as two-sided P value < 0.05.

Results

Fermi models overestimated myocardial blood flow in healthy volunteers due to arterial input function saturation in single bolus analysis compared to dual bolus analysis (P < 0.05). No difference was observed in these volunteers when applying distributed parameter-myocardial blood flow between single and dual bolus analysis. In patients, distributed parameter modeling was able to detect reduced myocardial blood flow at stress (<2.5 mL/min/mL of tissue) in all 12 stenotic vessels compared to only 9 for Fermi modeling.

Conclusions

Comparison of single bolus versus dual bolus values suggests that distributed parameter modeling is less dependent on arterial input function saturation than Fermi modeling. Distributed parameter modeling showed excellent accuracy in detecting reduced myocardial blood flow in all stenotic vessels.

Electronic supplementary material

The online version of this article (doi:10.1186/s12968-015-0125-1) contains supplementary material, which is available to authorized users.     

Stimulation of murine colony-forming cells with high proliferative potential by the combination of GM-CSF and CSF-1

Granulocyte-macrophage colony-stimulating factor (GM-CSF) has previously been shown to stimulate granulocyte, macrophage, and megakaryocyte lineages to act as an erythroid burst-promoting activity and to stimulate limited replication of spleen colony-forming cells. Here we demonstrate that murine GM-CSF alone or in combination with macrophage colony-stimulating factor (CSF-1) can stimulate colony- forming cells in bone marrow (BM) that have a high proliferative capacity. In cultures of BM from mice treated with 5-fluorouracil (FU) eight days before sampling, GM-CSF alone or in combination with CSF-1 stimulated the formation of large macrophage colonies with diameters greater than 0.5 mm. CSF-1 alone, at 800 units or greater, also stimulated larger colonies; however, these colonies were always less than 1.1 mm in diameter, whereas GM-CSF in combination with CSF-1 stimulated many colonies with diameters between 1 and 4 mm. At all doses of CSF-1 tested, the combination of factors resulted in a synergistic increase in colonies with diameters greater than 1.0 or 2.0 mm. Analysis of the incidence of colony-forming cells in the BM of normal mice and mice 2, 4, 6, and 8 days after FU treatment demonstrated that the progenitor cells stimulated by GM-CSF alone or in combination with CSF-1 were depleted by FU treatment in vivo and regenerated more rapidly than did the macrophage progenitors (M-CFC) stimulated by CSF-1 alone. This is similar to the properties of the previously described high-proliferative potential, colony-forming cell (HPP-CFC) that is responsive to interleukin-3 plus CSF-1 but not the HPP-CFC stimulated by hematopoietin 1 plus CSF-1. These data suggest that GM-CSF plus CSF-1 act synergistically to stimulate a population of progenitor cells that have a high proliferative potential and have properties similar to those of the population of HPP-CFC stimulated by interleukin-3 plus CSF-1.     

Lymphocyte depletion of donor bone marrow by counterflow centrifugal elutriation: results of a phase I clinical trial

We report here the results of a phase I clinical trial using counterflow centrifugal elutriation (CCE) for the removal of donor T lymphocytes before allogeneic bone marrow transplantation (BMT). Thirty- eight patients received lymphocyte-depleted allografts from HLA- identical, MLR-nonreactive sibling donors. The patients entered onto the study were either at high risk on the basis of age (median, 39 years) or disease status (acute leukemia in early relapse [ER], chronic myelogenous leukemia [CML] in accelerated phase [AP], or therapy resistant [RES] lymphoma). All patients received a standard lymphocyte dose of 1 x 10(6) morphologic lymphocytes per kilogram ideal body weight (BW) and were maintained on cyclosporine A (CsA) for 170 days after BMT. Prompt engraftment occurred in 37 of 38 patients with a median time to absolute neutrophil count (ANC) greater than 500/microL of 18 days. Although acute graft-v-host disease (GVHD; clinical stage I or greater) was observed in 45%, it was limited to the skin in all but five patients. Survival was related to disease status at the time of BMT. Among patients with acute leukemia in first or second remission, CML in chronic phase (CP) or lymphoma in partial remission (PR), 64% are currently alive, in contrast to 31% of patients with acute leukemia in third remission or early relapse, CML in second CP or AP, or RES lymphoma. Median follow-up for all patients was 351 days (range, 105 to 711 days). We conclude that this procedure is safe and warrants further evaluation in a randomized efficacy trial.     

Trace elements and Vitamin E status in Nigerian patients with prostate cancer

Background

Prostate cancer is the most common type of cancer among men.

Objectives

To investigate the trace elements (Se, Zn, Cu and Cd) and vitamin E status of some Nigerian prostate cancer (PCa) patients relative to their prostate-specific antigen (PSA) values.

Methods

Prostate cancer patients were assigned into groups 1, 2 and 3 with PSA of 5–10 ng/ml, 11–20 ng/ml and > 20 ng/ml, respectively.

Results

The results showed that the levels of whole blood superoxide dismutase (SOD) and serum Se and Zn were significantly lower (p< 0.05) in the PCa patients. Specifically, levels of SOD, Se and Zn decreased by 67%, 30% and 35%; 70%, 52% and 41%; 81%, 58% and 47%, in subjects with PSA of 5–10 ng/ml, 11–20 ng/ml and > 20 ng/ml, respectively. There were no significant differences (p> 0.05) in levels of Cu and Cd. Serum Cu/ Zn ratio were significantly higher in PCa patients. The Cu/ Zn ratios were 1: 1.2: 1.3 for subjects in groups 1, 2 and 3, respectively. Vitamin E levels in PCa patients were significantly lower and followed the order; normal > PSA (5–10) > PSA (11–20) > PSA (> 20).

Conclusions

Deficiency of vitamin E, Zn and Se may be risk factors for development of PCa.Key words: Lipid peroxidation, Prostate cancer, PSA values, Trace elements, Vitamin E     

Central nervous system involvement in patients with acute myeloid leukemia

Background/aim To evaluate the incidence, clinical features, risk factors, and prognosis of central nervous system (CNS) involvement in patients with acute myeloid leukemia (AML).Materials and methodsAll AML patients who were admitted to Hacettepe University hospital between 2000 and 2021 were evaluated. The medical records of 548 AML cases were retrospectively analyzed. Results The frequency of CNS involvement was 2.4% (n = 13) at diagnosis and 4.6% (n = 25) at diagnosis or during follow-up. Parenchymal involvement was seen in 5 patients, leptomeningeal involvement was seen in 11 patients. Three patients had both leptomeningeal and parenchymal involvements, and 6 patients had optic nerve or ocular involvement. In univariate analysis, younger age and extramedullary involvement at diagnosis were associated with CNS disease at diagnosis, and extramedullary involvement at diagnosis was associated with CNS disease during follow-up. In multivariate analysis; younger age and extramedullary involvement at diagnosis were associated with CNS disease at diagnosis and during follow-up respectively. Median overall survival was 5.4 months in patients with CNS disease at diagnosis and 16.9 months in patients with CNS disease during follow-up and 16.2 months in patients with no CNS disease.Conclusion CNS disease is a rare complication of AML. Younger age and extramedullary involvement at diagnosis are risk factors for CNS involvement.