Document Detail

Nomogram to estimate age-related MAC.
MedLine Citation:
PMID:  15220181     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: In clinical practice it is difficult to estimate rapidly two important values: (i) the total age-corrected MAC multiple from measured end-expired concentrations of volatile agent and nitrous oxide; (ii) the end-expired concentration of volatile agent needed to obtain a given total MAC multiple. We have developed a nomogram to do this. METHODS: We used standard nomogram methods to construct one single nomogram covering wide ranges of age (1-100 yr) and MAC (0.1-1.8 MAC) for halothane, enflurane, isoflurane, sevoflurane, and desflurane, alone or in combination with various concentrations of nitrous oxide. The user only has to draw two straight lines to obtain the desired result. RESULTS: The nomogram is simple to use. End-expired concentrations of halothane 0.48%, enflurane 1.05%, isoflurane 0.75%, sevoflurane 1.18%, or desflurane 4.3% in the presence of nitrous oxide 50% will give 1.4 MAC in a patient of 75 yr vs 0.9 MAC in a 1-yr-old. A reverse example is: a total MAC of 1.3 when using sevoflurane and nitrous oxide 67% in oxygen, requires an end-expired sevoflurane concentration of 1.8% in a 3-yr-old whereas 0.55% is needed in a patient of 90 yr. CONCLUSIONS: The nomogram gives accurate results if it covers a whole A4 sheet in landscape format and could be extended to apply to other agents, for example xenon.
J G C Lerou
Publication Detail:
Type:  Journal Article     Date:  2004-06-25
Journal Detail:
Title:  British journal of anaesthesia     Volume:  93     ISSN:  0007-0912     ISO Abbreviation:  Br J Anaesth     Publication Date:  2004 Aug 
Date Detail:
Created Date:  2004-07-14     Completed Date:  2004-09-28     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0372541     Medline TA:  Br J Anaesth     Country:  England    
Other Details:
Languages:  eng     Pagination:  288-91     Citation Subset:  IM    
Radboud University Nijmegen, Department of Anaesthesia, Geert Grooteplein 10, 6500 HB Nijmegen, The Netherlands.
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MeSH Terms
Age Factors
Aged, 80 and over
Aging / physiology*
Anesthetics, Inhalation / administration & dosage*,  pharmacokinetics
Child, Preschool
Middle Aged
Pulmonary Alveoli / metabolism
Reg. No./Substance:
0/Anesthetics, Inhalation

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