Simple method for the continuous noninvasive estimate of cardiac output using the maxima breathing system. A pilot study

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dc.contributor.authorMiller D.M.
dc.contributor.authorWessels J.A.
dc.date.accessioned2011-05-15T16:15:23Z
dc.date.available2011-05-15T16:15:23Z
dc.date.issued1997
dc.description.abstractThe Maxima is a new breathing system which makes it possible to monitor cardiac output (Q̇)noninvasively and to follow trends continuously. When used as a rebreathing system in controlled ventilation, the Maxima selectively eliminates alveolar gas and no fresh gas (V̇F) is eliminated. Without the need for a mixing chamber, eliminated CO2 (FĒCO2) may measured directly. With steady state conditions, and assuming a respiratory quotient of 1, carbon dioxide production (V̇CO2) = V̇F x FĒCO2. The indirect Fick principle applied to CO2 exchange (Q̇ = V̇CO2/venous-to-arterial CO2 content difference (C(a)CO2-C(v)CO2)) may be modified to Q̇ = V̇F x FĒCO2/(C(a)CO2-C(v)CO2). If V̇F in the breathing system is adjusted so that FĒCO2 is equal to C(a)CO2-C(v)CO2, then Q̇ = V̇F. It was found that, in the presence of a normal haemoglobin (13.3 g.dl-1, Q̇ = V̇F when V̇F was adjusted to achieve an FĒCO2 value of approximately 4.1%. Cardiac output estimates were compared with those obtained using a thermodilution technique in five patients undergoing coronary artery bypass grafting and in four patients with septicaemia in the ICU. Cardiac outputs were estimated from 1.VCO2 measurements and then 2. V̇CO2 and haemoglobin (Hb). The results of 28 measurements on nine patients with methods 1. and 2. respectively yielded a correlation with thermodilution measurements: coefficient r = 0.91 and 0.94 with a bias of -10.5% and -0.05% and an accuracy of 14% and 9%.
dc.description.versionArticle
dc.identifier.citationAnaesthesia and Intensive Care
dc.identifier.citation25
dc.identifier.citation1
dc.identifier.issn0310057X
dc.identifier.urihttp://hdl.handle.net/10019.1/13318
dc.subjectcarbon dioxide
dc.subjecthemoglobin
dc.subjectaccuracy
dc.subjectarterial carbon dioxide tension
dc.subjectarticle
dc.subjectartificial ventilation
dc.subjectblood carbon dioxide tension
dc.subjectbreathing apparatus
dc.subjectcalculation
dc.subjectclinical article
dc.subjectclinical trial
dc.subjectcoronary artery bypass graft
dc.subjectgas exchange
dc.subjectheart output
dc.subjecthuman
dc.subjectlung alveolus
dc.subjectmonitoring
dc.subjectrebreathing
dc.subjectrespiratory quotient
dc.subjectsepticemia
dc.subjectthermodilution
dc.subjectCapnography
dc.subjectCardiac Output
dc.subjectEquipment Design
dc.subjectHumans
dc.subjectMonitoring, Physiologic
dc.subjectPilot Projects
dc.subjectRespiration
dc.subjectThermodilution
dc.titleSimple method for the continuous noninvasive estimate of cardiac output using the maxima breathing system. A pilot study
dc.typeArticle
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