| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Clinical Trial |
Many clinical and research situations require maintenance of isocapnia, which occurs when alveolar ventilation (V'A) is matched to CO2 production. A simple, passive circuit that minimizes changes in V'A during hyperpnoea was devised. It is comprised of a manifold, with two gas inlets, attached to the intake port of a nonrebreathing circuit or ventilator. The first inlet receives a flow of fresh gas (CO2=0%) equal to the subject's minute ventilation (V'E). During hyperpnoea, the balance of V'E is drawn (inlet 2) from a reservoir containing gas, the carbon dioxide tension (PCO2) approximates that of mixed venous blood and therefore contributes minimally to V'A. Nine normal subjects breathed through the circuit for 4 min at 15-31 times resting levels. End-tidal PCO2 (Pet,CO2) at rest, 0, 1.5 and 3.0 min were (mean+/-SE) 5.1+/-0.1 kPa (38.1+/-1.1 mmHg), 4.9+/-0.1 kPa (36.4+/-1.1 mmHg), 5.0+/-0.2 kPa (37.8+/-1.6 mmHg) and 5.0+/-0.2 kPa (37.6+/-1.4 mmHg) (p=0.53, analysis of variance (ANOVA)), respectively; without the circuit, Pet,CO2 would be expected to have decreased by at least 2.7 kPa (20 mmHg). Six anaesthetized, intubated dogs were first ventilated at control levels and then hyperventilated by stepwise increases in either respiratory frequency (fR) from 10 to 24 min(-1) or tidal volume (VT) from 400 to 1,200 mL. Increases in fR did not significantly affect arterial CO2 tension (Pa,CO2) (p=0.28, ANOVA). Only the highest VT decreased Pa,CO2 from control (-0.5 +/- 0.3 kPa (-3.4 +/- 2.3 mmHg), p<0.05). In conclusion, this circuit effectively minimizes changes in alveolar ventilation and therefore arterial carbon dioxide tension during hyperpnoea.
This article has been cited by other articles:
|
|
 |
|
  R. Katznelson, L. Minkovich, Z. Friedman, L. Fedorko, W. S. Beattie, and J. A. Fisher Accelerated Recovery from Sevoflurane Anesthesia with Isocapnic Hyperpnoea Anesth. Analg., February 1, 2008; 106(2): 486 - 491. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Slessarev, J. Han, A. Mardimae, E. Prisman, D. Preiss, G. Volgyesi, C. Ansel, J. Duffin, and J. A. Fisher Prospective targeting and control of end-tidal CO2 and O2 concentrations J. Physiol., June 15, 2007; 581(3): 1207 - 1219. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. L. Chu, O. Jay, and M. D. White The effects of hyperthermia and hypoxia on ventilation during low-intensity steady-state exercise Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2007; 292(1): R195 - R203. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. D. Gilmore, C. Hudson, D. Preiss, and J. Fisher Retinal arteriolar diameter, blood velocity, and blood flow response to an isocapnic hyperoxic provocation Am J Physiol Heart Circ Physiol, June 1, 2005; 288(6): H2912 - H2917. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. D. Gilmore, C. Hudson, S. T. Venkataraman, D. Preiss, and J. Fisher Comparison of Different Hyperoxic Paradigms to Induce Vasoconstriction: Implications for the Investigation of Retinal Vascular Reactivity Invest. Ophthalmol. Vis. Sci., September 1, 2004; 45(9): 3207 - 3212. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Vesely, J. A. Fisher, N. Sasano, D. Preiss, R. Somogyi, H. El-Beheiry, A. Prabhu, and H. Sasano Isocapnic hyperpnoea accelerates recovery from isoflurane anaesthesia Br. J. Anaesth., December 1, 2003; 91(6): 787 - 792. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Sasano, A. E. Vesely, S. Iscoe, J. C. Tesler, and J. A. Fisher A Simple Apparatus for Accelerating Recovery from Inhaled Volatile Anesthetics Anesth. Analg., November 1, 2001; 93(5): 1188 - 1191. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. C. KRECK, E. D. SHADE, W. J. E. LAMM, S. E. MCKINNEY, and M. P. HLASTALA Isocapnic Hyperventilation Increases Carbon Monoxide Elimination and Oxygen Delivery Am. J. Respir. Crit. Care Med., February 1, 2001; 163(2): 458 - 462. [Abstract] [Full Text]
|
|
|
|
 |
|
 J. A. Silverman, L. Z. Sommer, A. Robicsek, J. Dickstein, A. Greenberg, J. Kruger, J. Rucker, G. Volgyesi, J. A. Fisher, and S. Iscoe Tracheal constrictor drive above the apneic threshold in anesthetized dogs J Appl Physiol, December 1, 2000; 89(6): 2258 - 2262. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. TAKEUCHI, A. VESELY, J. RUCKER, L. Z. SOMMER, J. TESLER, E. LAVINE, A. S. SLUTSKY, W. H. MALECK, G. VOLGYESI, L. FEDORKO, et al. A Simple "New" Method to Accelerate Clearance of Carbon Monoxide Am. J. Respir. Crit. Care Med., June 1, 2000; 161(6): 1816 - 1819. [Abstract] [Full Text]
|
|
|
|
|
|
R. B. Banzett, R. T. Garcia, and S. H. Moosavi Simple contrivance "clamps" end-tidal PCO2 and PO2 despite rapid changes in ventilation J Appl Physiol, May 1, 2000; 88(5): 1597 - 1600. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. Simpson, J. E. van Eyk, and S. Iscoe Hypoxemia-induced modification of troponin I and T in canine diaphragm J Appl Physiol, February 1, 2000; 88(2): 753 - 760. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. FISHER, J. RUCKER, L. Z. SOMMER, A. VESELY, E. LAVINE, Y. GREENWALD, G. VOLGYESI, L. FEDORKO, and S. ISCOE Isocapnic Hyperpnea Accelerates Carbon Monoxide Elimination Am. J. Respir. Crit. Care Med., April 1, 1999; 159(4): 1289 - 1292. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
