Document Detail

Transient decrease in PaCO(2) and asymmetric chest wall dynamics in early progressing pneumothorax.
MedLine Citation:
PMID:  23179332     Owner:  NLM     Status:  Publisher    
PURPOSE: Diagnosis of pneumothorax (PTX) in newborn infants has been reported as late. To explore diagnostic indices for early detection of progressing PTX, and offer explanations for delayed diagnoses. METHODS: Progressing PTX was created in rabbits (2.3 ± 0.5 kg, n = 7) by injecting 1 ml/min of air into the pleural space. Hemodynamic parameters, tidal volume, EtCO(2), SpO(2), blood gas analyses and chest wall tidal displacements (TDi) on both sides of the chest were recorded. RESULTS: (Mean ± SD): A decrease in SpO(2) below 90 % was detected only after 46.6 ± 11.3 min in six experiments. In contrary to the expected gradual increase of CO(2), there was a prolonged transient decrease of 14.2 ± 4.5 % in EtCO(2) (p < 0.01), and a similar decrease in PaCO(2) (p < 0.025). EtCO(2) returned back to baseline only after 55.2 ± 24.7 min, and continued to rise thereafter. The decrease in CO(2) was a mirror image of the 14.6 ± 5.3 % increase in tidal volume. The analysis of endotracheal flow and pressure dynamics revealed a paradoxical transient increase in the apparent compliance. Significant decrease in mean arterial blood pressure was observed after 46.2 ± 40.1 min. TDi provided the most sensitive and earliest sign of PTX, decreasing on the PTX side after 16.1 ± 7.2 min. The TDi progressively decreased faster and lower on the PTX side, thus enabling detection of asymmetric ventilation. CONCLUSIONS: The counterintuitive transient prolonged decrease in CO(2) without changes in SpO(2) may explain the delay in diagnosis of PTX encountered in the clinical environment. An earlier indication of asymmetrically decreased ventilation on the affected side was achieved by monitoring the TDi.
Dan Waisman; Anna Faingersh; Carmit Levy; Ifat Colman-Klotzman; Avi Rotschild; Oscar Lichtenstein; Amir Landesberg
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-11-21
Journal Detail:
Title:  Intensive care medicine     Volume:  -     ISSN:  1432-1238     ISO Abbreviation:  Intensive Care Med     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-26     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7704851     Medline TA:  Intensive Care Med     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Department of Neonatology, Faculty of Medicine, Carmel Medical Center, 7 Michal St, 34632, Haifa, Israel,
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