Journal article
Regional Lung Derecruitment and Inflammation during 16 Hours of Mechanical Ventilation in Supine Healthy Sheep
Anesthesiology (Philadelphia), Vol.119(1), pp.156-165
07/01/2013
DOI: 10.1097/ALN.0b013e31829083b8
PMCID: PMC4123654
PMID: 23535501
Abstract
Background:
Lung derecruitment is common during general anesthesia. Mechanical ventilation with physiological tidal volumes could magnify derecruitment, and produce lung dysfunction and inflammation. The authors used positron emission tomography to study the process of derecruitment in normal lungs ventilated for 16 h and the corresponding changes in regional lung perfusion and inflammation.
Methods:
Six anesthetized supine sheep were ventilated with V-T = 8 ml/kg and positive end-expiratory pressure = 0. Transmission scans were performed at 2-h intervals to assess regional aeration. Emission scans were acquired at baseline and after 16 h for the following tracers: (1) F-18-fluorodeoxyglucose to evaluate lung inflammation and (2) (NN)-N-13 to calculate regional perfusion and shunt fraction.
Results:
Gas fraction decreased from baseline to 16 h in dorsal (0.31 +/- 0.13 to 0.14 +/- 0.12, P < 0.01), but not in ventral regions (0.61 +/- 0.03 to 0.63 +/- 0.07, P = nonsignificant), with time constants of 1.5-44.6 h. Although the vertical distribution of relative perfusion did not change from baseline to 16 h, shunt increased in dorsal regions (0.34 +/- 0.23 to 0.63 +/- 0.35, P < 0.01). The average pulmonary net F-18-fluorodeoxyglucose uptake rate in six regions of interest along the ventral-dorsal direction increased from 3.4 +/- 1.4 at baseline to 4.1 +/- 1.510(-3)/min after 16 h (P < 0.01), and the corresponding average regions of interest F-18-fluorodeoxyglucose phosphorylation rate increased from 2.0 +/- 0.2 to 2.5 +/- 0.210(-2)/min (P < 0.01).
Conclusions:
When normal lungs are mechanically ventilated without positive end-expiratory pressure, loss of aeration occurs continuously for several hours and is preferentially localized to dorsal regions. Progressive lung derecruitment was associated with increased regional shunt, implying an insufficient hypoxic pulmonary vasoconstriction. The increased pulmonary net uptake and phosphorylation rates of F-18-fluorodeoxyglucose suggest an incipient inflammation in these initially normal lungs.
Details
- Title: Subtitle
- Regional Lung Derecruitment and Inflammation during 16 Hours of Mechanical Ventilation in Supine Healthy Sheep
- Creators
- Mauro R. Tucci - Massachusetts General HospitalEduardo L. V. Costa - Massachusetts General HospitalTyler J. Wellman - Boston UniversityGuido Musch - Massachusetts General HospitalTilo Winkler - Massachusetts General HospitalR. Scott Harris - Massachusetts General HospitalJose G. Venegas - Massachusetts General HospitalMarcelo B. P. Amato - Universidade de São PauloMarcos F. Vidal Melo - American Society of Anesthesiologists
- Resource Type
- Journal article
- Publication Details
- Anesthesiology (Philadelphia), Vol.119(1), pp.156-165
- DOI
- 10.1097/ALN.0b013e31829083b8
- PMID
- 23535501
- PMCID
- PMC4123654
- NLM abbreviation
- Anesthesiology
- ISSN
- 0003-3022
- eISSN
- 1528-1175
- Publisher
- Lippincott Williams & Wilkins
- Number of pages
- 10
- Grant note
- 5R01HL086827 / National Institutes of Health, Bethesda, Maryland; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA Coordination for the Improvement of Higher Level Personnel, Brasilia, Brazil R01HL094639 / National Institutes of Health; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA R01HL086827 / NATIONAL HEART, LUNG, AND BLOOD INSTITUTE; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA; NIH National Heart Lung & Blood Institute (NHLBI)
- Language
- English
- Date published
- 07/01/2013
- Academic Unit
- Anesthesia
- Record Identifier
- 9985142949902771
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