Format

Send to

Choose Destination
BMC Anesthesiol. 2017 Mar 23;17(1):49. doi: 10.1186/s12871-017-0342-2.

Effects of short-term hyperoxia on erythropoietin levels and microcirculation in critically Ill patients: a prospective observational pilot study.

Author information

1
Anesthesia and Intensive Care Unit, Department of Biomedical Sciences and Public Health, Università Politecnica delle Marche, via Tronto 10, 6126, Torrette di Ancona, Italy. a.donati@univpm.it.
2
Anesthesia and Intensive Care Unit, Department of Biomedical Sciences and Public Health, Università Politecnica delle Marche, via Tronto 10, 6126, Torrette di Ancona, Italy.
3
Department of Anesthesiology and Intensive Care, Modena University Hospital, L.go del Pozzo 71, 41100, Modena, Italy.
4
Department of Clinical Sciences, Section of Biochemistry, Università Politecnica delle Marche, via Tronto 10, 60126, Torrette di Ancona, Italy.
5
Bloomsbury Institute of Intensive Care Medicine, University College London, Gower Street, London, WC1E 6BT, UK.

Abstract

BACKGROUND:

The normobaric oxygen paradox states that a short exposure to normobaric hyperoxia followed by rapid return to normoxia creates a condition of 'relative hypoxia' which stimulates erythropoietin (EPO) production. Alterations in glutathione and reactive oxygen species (ROS) may be involved in this process. We tested the effects of short-term hyperoxia on EPO levels and the microcirculation in critically ill patients.

METHODS:

In this prospective, observational study, 20 hemodynamically stable, mechanically ventilated patients with inspired oxygen concentration (FiO2) ≤0.5 and PaO2/FiO2 ≥ 200 mmHg underwent a 2-hour exposure to hyperoxia (FiO2 1.0). A further 20 patients acted as controls. Serum EPO was measured at baseline, 24 h and 48 h. Serum glutathione (antioxidant) and ROS levels were assessed at baseline (t0), after 2 h of hyperoxia (t1) and 2 h after returning to their baseline FiO2 (t2). The microvascular response to hyperoxia was assessed using sublingual sidestream dark field videomicroscopy and thenar near-infrared spectroscopy with a vascular occlusion test.

RESULTS:

EPO increased within 48 h in patients exposed to hyperoxia from 16.1 [7.4-20.2] to 22.9 [14.1-37.2] IU/L (p = 0.022). Serum ROS transiently increased at t1, and glutathione increased at t2. Early reductions in microvascular density and perfusion were seen during hyperoxia (perfused small vessel density: 85% [95% confidence interval 79-90] of baseline). The response after 2 h of hyperoxia exposure was heterogeneous. Microvascular perfusion/density normalized upon returning to baseline FiO2.

CONCLUSIONS:

A two-hour exposure to hyperoxia in critically ill patients was associated with a slight increase in EPO levels within 48 h. Adequately controlled studies are needed to confirm the effect of short-term hyperoxia on erythropoiesis.

TRIAL REGISTRATION:

ClinicalTrials.gov ( www.clinicaltrials.gov ), NCT02481843 , registered 15th June 2015, retrospectively registered.

KEYWORDS:

Anemia; Erythropoietin; Microcirculation; Normobaric hyperoxia

PMID:
28335733
PMCID:
PMC5364633
DOI:
10.1186/s12871-017-0342-2
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for BioMed Central Icon for PubMed Central
Loading ...
Support Center