Difference between end-tidal and arterial PCO2 in exercise

Jones, Norman L.; Robertson, D. G.; Kane, John

doi:10.1152/jappl.1979.47.5.954

Cited by 361 publications

(279 citation statements)

References 0 publications

Supporting

Mentioning

257

Contrasting

Unclassified

Order By: Relevance

“…During exercise and related hypercapnia, P ET CO 2 may slightly overestimate arterial PCO 2 (Jones et al 1979;Peebles et al 2007). Although this is a relevant consideration, we feel that this is unlikely to affect our findings since we used otherwise healthy subjects and we know of no evidence to indicate that end-tidal to arterial PCO 2 gradients may be altered with aging.…”

Section: Methodological Considerationsmentioning

confidence: 89%

Aging blunts hyperventilation-induced hypocapnia and reduction in cerebral blood flow velocity during maximal exercise

Marsden

Haykowsky

Smirl

et al. 2011

AGE

View full text Add to dashboard Cite

Cerebral blood flow (CBF) increases from rest to ∼60% of peak oxygen uptake (VO 2peak ) and thereafter decreases towards baseline due to hyperventilation-induced hypocapnia and subsequent cerebral vasoconstriction. It is unknown what happens to CBF in older adults (OA), who experience a decline in CBF at rest coupled with a blunted ventilatory response during VO 2peak . In 14 OA (71±10 year) and 21 young controls (YA; 23±4 years), we hypothesized that OA would experience less hyperventilationinduced cerebral vasoconstriction and therefore an attenuated reduction in CBF at VO 2peak . Incremental exercise was performed on a cycle ergometer, whilst bilateral middle cerebral artery blood flow velocity (MCA V mean ; transcranial Doppler ultrasound), heart rate (HR; ECG) and end-tidal PCO 2 (P ET CO 2 ) were monitored continuously. Blood pressure (BP) was monitored intermittently. From rest to 50% of VO 2peak , despite greater elevations in BP in OA, the change in MCA V mean was greater in YA compared to OA (28% vs. 15%, respectively; P<0.0005). In the YA, at intensities >70% of VO 2peak , the hyperventilationinduced declines in both P ET CO 2 (14 mmHg (YA) vs. 4 mmHg (OA); P<0.05) and MCA V mean (−21% (YA) vs. −7% (OA); P<0.0005) were greater in YA compared to OA. Our findings show (1), from rest-tomild intensity exercise (50% VO 2peak ), elevations in CBF are reduced in OA and (2) age-related declines in hyperventilation during maximal exercise result in less hypocapnic-induced cerebral vasoconstriction.

show abstract

Section: Methodological Considerationsmentioning

confidence: 89%

Aging blunts hyperventilation-induced hypocapnia and reduction in cerebral blood flow velocity during maximal exercise

Marsden

Haykowsky

Smirl

et al. 2011

AGE

View full text Add to dashboard Cite

show abstract

“…3-5 Tidal volume-dependent negative gradients were observed during exercise. 19 Fletcher and Jonson 2~ reported negative gradients in 12% of patients with large tidal volumes and low respiratory rates. An increase in tidal volume and decrease in respiratory frequency causes improved ventilation of dependent and well perfused aiveoli.…”

Section: Discussionmentioning

confidence: 97%

Stability of the arterial to end-tidal carbon dioxide difference during anaesthesia for prolonged neurosurgical procedures

1995

View full text Add to dashboard Cite

This study was undertaken to examine the variation of the arterial to One of the major treatment modalities used by anaesthetists for the management of raised intracmnial pressure (ICP) in neurosurgical patients is hyperventilation, which reduces arterial PaCO2. Hyperventilation to a PaCO2 of 25-30 mmHg is the mainstay of acute and subacute management of raised ICE It is well known that PaCO2 correlates inversely with cerebral arterial resistance. As a con-CAN J ANAESTH 19~5 ] 42: 6 / pp 498-503

show abstract

“…Although very complex, this may partially be explained by infants' increased CO2 production, which has been demonstrated to increase ETCO2 to levels approaching venous CO2. 12 Dilution of expired CO2 within the small infant endotracheal tube appears to be minimal as the ETCO2 within the proximal endotracheal tube is not different from the PaCO2. However, once the expired gas enters the larger proximal connector, dilution occurs, and ETCO2 is significantly lower than PaCO2.…”

Section: Discussionmentioning

confidence: 97%

Continuous end-tidal CO2 sampling within the proximal endotracheal tube estimates arterial CO2 tension in infants

Rich

Sconzo

1991

Can J Anaesth

View full text Add to dashboard Cite

End-tidal C02 (ETC02) sampled using a 22-gauge needle inserted through the wall of the proximal endotracheal tube was compared with ETC02 obtained from the standard proximal connector to determine which was the more accurate sampling site for estimation of arterial C02 tension (PaC02Accurate ETCO2 measurement is more difficult in infants than in adults because the relatively small tidal volume in conjunction with high fresh gas flows dilutes expired CO2 leading to underestimation of PaCO2.1-4 To minimize the problem of expired gas dilution, Badgwell recommended sampling ETCO2 from the distal tip of the endotracheal tube to assess accurately the PaCO2 in infants and children. 5'6 Recently, Bissonette described a technique to estimate PaCO2 accurately in children which may be simpler than distal sampling of ETCO2. 7 Insertion of a needle through the wall of the proximal end of the endotracheal tube while the fresh gas flow was discontinued allowed single-breath analysis of ETCO2. We recently showed, in a rabbit model, that sampling of ETCO2 within the proximal endotracheal tube provided a good estimation of PaCO2 without discontinuing fresh gas flow. 8 Continuous sampling of ETCO2 within the proximal endotracheal tube in infants during ventilation with a circle system without discontinuing fresh gas flow has not been evaluated. In this study, we assessed the accuracy of continuous ETCO2 sampling via needle aspiration from the proximal end of the endotracheal tube compared with the ETCO2 obtained from the standard proximal connector in infants less than one year old. MethodsThis study was approved by the University of Virginia Human Investigations Committee. Fourteen infants, ASA physical status II or Ill, were scheduled for major neurological, reconstructive or cardiothoracic surgery. Following induction of anaesthesia, the tracheas were CAN J ANAESTH 1991 / 38:2 / pp201-3

show abstract

Difference between end-tidal and arterial PCO2 in exercise

Cited by 361 publications

References 0 publications

Aging blunts hyperventilation-induced hypocapnia and reduction in cerebral blood flow velocity during maximal exercise

Aging blunts hyperventilation-induced hypocapnia and reduction in cerebral blood flow velocity during maximal exercise

Stability of the arterial to end-tidal carbon dioxide difference during anaesthesia for prolonged neurosurgical procedures

Continuous end-tidal CO2 sampling within the proximal endotracheal tube estimates arterial CO2 tension in infants

Contact Info

Product

Resources

About