Document Detail

Effects of surgical stimulation on the apnoeic thresholds for carbon dioxide during anaesthesia with sevoflurane.
MedLine Citation:
PMID:  7826782     Owner:  NLM     Status:  MEDLINE    
Mechanical hyperventilation may produce hypocapnic apnoea below the carbon dioxide off-switch threshold whereas an increase in arterial PCO2 after post-hyperventilation apnoea causes reappearance of respiratory effort above the carbon dioxide on-switch threshold. To study the effects of surgical stimulation on these two thresholds, we have measured end-tidal PCO2 (PE'CO2) at the two thresholds, before and during surgical stimulation, in 14 patients undergoing mastectomy, anaesthetized with sevoflurane (1.2 MAC). Based on the reproducibility of the results, data from 11 patients were analysed and data from the three other patients were discarded. Before surgical stimulation, mean resting PE'CO2' off-switch threshold and on-switch threshold were 5.7 (SEM 0.2), 5.2 (0.2) and 6.1 (0.2) kPa, respectively. The off-switch threshold was significantly less than resting PE'CO2 (P < 0.01) but the on-switch threshold was significantly greater than resting PE'CO2 (P < 0.01). During surgical stimulation, resting PE'CO2' off-switch threshold and on-switch threshold were 4.8 (0.2), 4.1 (0.2) and 4.7 (0.2) kPa, respectively. Although the off-switch threshold was significantly less than resting PE'CO2 (P < 0.01), there were no significant differences between resting PE'CO2 and on-switch threshold. These results indicate that surgical stimulation does not affect equally the carbon dioxide on- and off-switch thresholds.
T Nishino; T Kochi
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  British journal of anaesthesia     Volume:  73     ISSN:  0007-0912     ISO Abbreviation:  Br J Anaesth     Publication Date:  1994 Nov 
Date Detail:
Created Date:  1995-02-21     Completed Date:  1995-02-21     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0372541     Medline TA:  Br J Anaesth     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  583-6     Citation Subset:  IM    
Department of Anaesthesia, National Cancer Center Hospital East, Chiba, Japan.
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MeSH Terms
Airway Resistance
Anesthesia, General*
Apnea / etiology
Carbon Dioxide / physiology
Mastectomy, Modified Radical
Methyl Ethers*
Middle Aged
Respiration / physiology*
Respiration, Artificial
Tidal Volume
Reg. No./Substance:
0/Anesthetics; 0/Ethers; 0/Methyl Ethers; 124-38-9/Carbon Dioxide; 28523-86-6/sevoflurane

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