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Home / Equine Research Bank / Can J Vet Res / Cardiopulmonary effects of hypercapnia during controlled int...
Canadian journal of veterinary research = Revue canadienne de recherche veterinaire1995; 59(3); 213-221;

Cardiopulmonary effects of hypercapnia during controlled intermittent positive pressure ventilation in the horse.

Abstract: The cardiopulmonary effects of eucapnia (arterial CO2 tension [PaCO2] 40.4 +/- 2.9 mm Hg, mean +/- SD), mild hypercapnia (PaCO2, 59.1 +/- 3.5 mm Hg), moderate hypercapnia (PaCO2, 82.6 +/- 4.9 mm Hg), and severe hypercapnia (PaCO2, 110.3 +/- 12.2 mm Hg) were studied in 8 horses during isoflurane anesthesia with volume controlled intermittent positive pressure ventilation (IPPV) and neuromuscular blockade. The sequence of changes in PaCO2 was randomized. Mild hypercapnia produced bradycardia resulting in a significant (P < 0.05) decrease in cardiac index (CI) and oxygen delivery (DO2), while hemoglobin concentration (Hb), the hematocrit (Hct), systolic blood pressure (SBP), mean blood pressure (MBP), systemic vascular resistance (SVR), and venous admixture (QS/QT) increased significantly. Moderate hypercapnia resulted in a significant rise in CI, stroke index (SI), SBP, MBP, mean pulmonary artery pressure (PAP), Hct, Hb, arterial oxygen content (CaO2), mixed venous oxygen content (CvO2), and DO2, with heart rate (HR) staying below eucapnic levels. Severe hypercapnia resulted in a marked rise in HR, CI, SI, SBP, PAP, Hct, Hb, CaO2, CvO2, and DO2. Systemic vascular resistance was significantly decreased, while MBP levels were not different from those during moderate hypercapnia. No cardiac arrhythmias were recorded with any of the ranges of PaCO2. Norepinephrine levels increased progressively with each increase in PaCO2, whereas plasma cortisol levels remained unchanged. It was concluded that hypercapnia in isoflurane-anesthetized horses elicits a biphasic cardiopulmonary response, with mild hypercapnia producing a fall in CI and DO2 despite an increase in MBP, while moderate and severe hypercapnia produce an augmentation of the cardiopulmonary performance and DO2.
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Publication Date: 1995-07-01 PubMed ID: 8521355PubMed Central: PMC1263768
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  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research explores how different levels of carbon dioxide (hypercapnia) in the blood affect the cardiovascular and pulmonary functions in horses under anesthesia, using intermittent positive pressure ventilation.

Research Procedure

  • The research was performed on eight horses undergoing isoflurane anesthesia, a commonly used inhalational anesthetic in veterinary medicine, paired with intermittent positive pressure ventilation (IPPV) and neuromuscular blockage.
  • The experimented included three stages of hypercapnia – mild hypercapnia (arterial CO2 tension [PaCO2] of 59.1 +/- 3.5 mm Hg), moderate hypercapnia (PaCO2 of 82.6 +/- 4.9 mm Hg) and severe hypercapnia (PaCO2 of 110.3 +/- 12.2 mm Hg). The changes in PaCO2 were randomized.

Mild Hypercapnia

  • Mild hypercapnia resulted in slower heart rate (bradycardia), leading to a significant decrease in the cardiac index (measure of heart function) and oxygen delivery.
  • Mild hypercapnia also led to an increase in hemoglobin concentration, hematocrit (volume percentage of red blood cells), systolic blood pressure, mean blood pressure, systemic vascular resistance (resistance to blood flow in blood vessels), and venous admixture (percentage of blood that is not fully oxygenated).

Moderate Hypercapnia

  • Moderate hypercapnia led to a significant increase in cardiac index, stroke index (amount of blood pumped by the heart with each beat), as well as systolic and mean blood pressures.
  • It also elevated the mean pulmonary artery pressure, hematocrit, hemoglobin, and various measures of oxygen content, while the heart rate stayed below the eucapnic (normal blood CO2 level) state.

Severe Hypercapnia

  • Severe hypercapnia caused a dramatic increase in heart rate, cardiac index, stroke index, systolic blood pressure, and pulmonary artery pressure.
  • There was also a rise in hematocrit, hemoglobin concentration, and measures of arterial and venous oxygen content.
  • Interestingly, systemic vascular resistance significantly decreased, offsetting changes in mean blood pressure.

Other Findings

  • Norepinephrine (hormone that raises blood pressure) levels proportionally increased with each hypercapnia level.
  • There were no recorded cardiac arrhythmias (abnormal heart rhythms), and plasma cortisol levels (stress hormone) remained stable across all hypercapnia levels.

Conclusion

  • The research concluded that elevated blood CO2 levels cause a two-phase cardiopulmonary response in these anesthesia-induced horses. Mild hypercapnia reduces cardiac output and oxygen delivery, despite increased mean blood pressure. In contrast, moderate to severe hypercapnia enhances cardiac performance and oxygen delivery.

Cite This Article

APA
Khanna AK, McDonell WN, Dyson DH, Taylor PM. (1995). Cardiopulmonary effects of hypercapnia during controlled intermittent positive pressure ventilation in the horse. Can J Vet Res, 59(3), 213-221.

Publication

Canadian journal of veterinary research = Revue canadienne de recherche veterinaire
ISSN: 0830-9000
NlmUniqueID: 8607793
Country: Canada
Language: English
Volume: 59
Issue: 3
Pages: 213-221

Researcher Affiliations

Khanna, A K
  • Department of Clinical Studies, Ontario Veterinary College, University of Guelph.
McDonell, W N
    Dyson, D H
      Taylor, P M

        MeSH Terms

        • Anesthetics, Inhalation
        • Animals
        • Carbon Dioxide / pharmacology
        • Dose-Response Relationship, Drug
        • Female
        • Hemodynamics
        • Horses
        • Hypercapnia / veterinary
        • Intermittent Positive-Pressure Ventilation / veterinary
        • Isoflurane
        • Male
        • Nerve Block / veterinary
        • Respiration
        • Respiratory Function Tests

        References

        This article includes 41 references
        1. Steffey EP, Hodgson DS, Dunlop CI, Miller MF, Woliner MJ, Heath RB, Grandy J. Cardiopulmonary function during 5 hours of constant-dose isoflurane in laterally recumbent, spontaneously breathing horses.. J Vet Pharmacol Ther 1987 Dec;10(4):290-7.
          pubmed: 3437493doi: 10.1111/j.1365-2885.1987.tb00104.xgoogle scholar: lookup
        2. Donaldson LL. Retrospective assessment of dobutamine therapy for hypotension in anesthetized horses.. Vet Surg 1988 Jan-Feb;17(1):53-7.
          pubmed: 3256143doi: 10.1111/j.1532-950x.1988.tb00275.xgoogle scholar: lookup
        3. Cingolani HE, Faulkner SL, Mattiazzi AR, Bender HW, Graham TP Jr. Depression of human myocardial contractility with "respiratory" and "metabolic" acidosis.. Surgery 1975 Mar;77(3):427-32.
          pubmed: 1124498
        4. Sarazan RD, Starke WA, Krause GF, Garner HE. Cardiovascular effects of detomidine, a new alpha 2-adrenoceptor agonist, in the conscious pony.. J Vet Pharmacol Ther 1989 Dec;12(4):378-88.
          pubmed: 2575673doi: 10.1111/j.1365-2885.1989.tb00688.xgoogle scholar: lookup
        5. Wagner AE, Bednarski RM, Muir WW 3rd. Hemodynamic effects of carbon dioxide during intermittent positive-pressure ventilation in horses.. Am J Vet Res 1990 Dec;51(12):1922-9.
          pubmed: 2128172
        6. SECHZER PH, EGBERT LD, LINDE HW, COOPER DY, DRIPPS RD, PRICE HL. Effect of carbon dioxide inhalation on arterial pressure, ECG and plasma catecholamines and 17-OH corticosteroids in normal man.. J Appl Physiol 1960 May;15:454-8.
          pubmed: 14444401doi: 10.1152/jappl.1960.15.3.454google scholar: lookup
        7. Marshall BE, Cohen PJ, Klingenmaier CH, Neigh JL, Pender JW. Some pulmonary and cardiovascular effects of enflurane (Ethrane) anaesthesia with varying Pa CO2 in man.. Br J Anaesth 1971 Nov;43(11):996-1002.
          pubmed: 5131470
        8. Manley SV. Monitoring the anesthetized horse.. Vet Clin North Am Large Anim Pract 1981 May;3(1):111-33.
          pubmed: 7023007doi: 10.1016/s0196-9846(17)30149-0google scholar: lookup
        9. Steffey EP, Howland D Jr. Comparison of circulatory and respiratory effects of isoflurane and halothane anesthesia in horses.. Am J Vet Res 1980 May;41(5):821-5.
          pubmed: 7406305
        10. Cullen DJ, Eger EI 2nd, Gregory GA. The cardiovascular effects of carbon dioxide in man, conscious and during cyclopropane anesthesia.. Anesthesiology 1969 Nov;31(5):407-13.
          pubmed: 5345291doi: 10.1097/00000542-196911000-00004google scholar: lookup
        11. Cullen DJ, Eger EI 2nd. Cardiovascular effects of carbon dioxide in man.. Anesthesiology 1974 Oct;41(4):345-9.
          pubmed: 4412334doi: 10.1097/00000542-197410000-00006google scholar: lookup
        12. Hellyer PW, Bednarski RM, Hubbell JA, Muir WW 3rd. Effects of halothane and isoflurane on baroreflex sensitivity in horses.. Am J Vet Res 1989 Dec;50(12):2127-34.
          pubmed: 2610441
        13. Cingolani HE, Mattiazzi AR, Blesa ES, Gonzalez NC. Contractility in isolated mammalian heart muscle after acid-base changes.. Circ Res 1970 Mar;26(3):269-78.
          pubmed: 5415858doi: 10.1161/01.res.26.3.269google scholar: lookup
        14. Wetmore LA, Derksen FJ, Blaze CA, Eyster GE. Mixed venous oxygen tension as an estimate of cardiac output in anesthetized horses.. Am J Vet Res 1987 Jun;48(6):971-6.
          pubmed: 3605814
        15. Steffey EP, Howland D Jr. Cardiovascular effects of halothane in the horse.. Am J Vet Res 1978 Apr;39(4):611-5.
          pubmed: 646195
        16. Cullen LK, Steffey EP, Bailey CS, Kortz G, da Silva Curiel J, Bellhorn RW, Woliner MJ, Elliott AR, Jarvis KA. Effect of high PaCO2 and time on cerebrospinal fluid and intraocular pressure in halothane-anesthetized horses.. Am J Vet Res 1990 Feb;51(2):300-4.
          pubmed: 2301844
        17. Boyd CJ, McDonell WN, Valliant A. Comparative hemodynamic effects of halothane and halothane-acepromazine at equipotent doses in dogs.. Can J Vet Res 1991 Apr;55(2):107-12.
          pubmed: 1884290
        18. Steffey EP, Kelly AB, Hodgson DS, Grandy JL, Woliner MJ, Willits N. Effect of body posture on cardiopulmonary function in horses during five hours of constant-dose halothane anesthesia.. Am J Vet Res 1990 Jan;51(1):11-6.
          pubmed: 2301808
        19. Nyman G, Funkquist B, Kvart C. Postural effects on blood gas tension, blood pressure, heart rate, ECG and respiratory rate during prolonged anaesthesia in the horse.. Zentralbl Veterinarmed A 1988 Jan;35(1):54-62.
          pubmed: 3128026doi: 10.1111/j.1439-0442.1988.tb00006.xgoogle scholar: lookup
        20. Cromwell TH, Stevens WC, Eger EI 2nd, Shakespeare TF, Halsey MJ, Bahlman SH, Fourcade HE. The cardiovascular effects of compound 469 (Forane) during spontaneous ventilation and CO2 challenge in man.. Anesthesiology 1971 Jul;35(1):17-25.
          pubmed: 4932618doi: 10.1097/00000542-197107000-00007google scholar: lookup
        21. Silver M, Fowden AL, Knox J, Ousey JC, Franco R, Rossdale PD. Sympathoadrenal and other responses to hypoglycaemia in the young foal.. J Reprod Fertil Suppl 1987;35:607-14.
          pubmed: 3479615
        22. Steffey EP, Wheat JD, Meagher DM, Norrie RD, McKee J, Brown M, Arnold J. Body position and mode of ventilation influences arterial pH, oxygen, and carbon dioxide tensions in halothane-anesthetized horses.. Am J Vet Res 1977 Mar;38(3):379-82.
          pubmed: 15488
        23. Norman J, Atkinson SA. The effect of cardiac sympathetic blockade on the relationship between cardiac output and carbon dioxide tension in the anaesthetized dog.. Br J Anaesth 1970 Jul;42(7):592-602.
          pubmed: 4393844doi: 10.1093/bja/42.7.592google scholar: lookup
        24. Gallivan GJ, McDonell WN, Forrest JB. Comparative ventilation and gas exchange in the horse and the cow.. Res Vet Sci 1989 May;46(3):331-6.
          pubmed: 2740627
        25. Hall LW. Disturbances of cardiopulmonary function in anaesthetised horses.. Equine Vet J 1971 Jul;3(3):95-8.
          pubmed: 4949803doi: 10.1111/j.2042-3306.1971.tb04447.xgoogle scholar: lookup
        26. Wattwil LM, Olsson JG. Circulatory effects of isoflurane during acute hypercapnia.. Anesth Analg 1987 Dec;66(12):1234-9.
          pubmed: 3688495
        27. Dunlop CI, Steffey EP, Miller MF, Woliner MJ. Temporal effects of halothane and isoflurane in laterally recumbent ventilated male horses.. Am J Vet Res 1987 Aug;48(8):1250-5.
          pubmed: 3631716
        28. Cullen BF, Eger EI 2nd, Smith NT, Sawyer DC, Gregory GA. The circulatory response to hypercapnia during fluroxene anesthesia in man.. Anesthesiology 1971 May;34(5):415-20.
          pubmed: 4396618doi: 10.1097/00000542-197105000-00008google scholar: lookup
        29. Dyson DH, Pascoe PJ. Influence of preinduction methoxamine, lactated Ringer solution, or hypertonic saline solution infusion or postinduction dobutamine infusion on anesthetic-induced hypotension in horses.. Am J Vet Res 1990 Jan;51(1):17-21.
          pubmed: 2301816
        30. Muir WW, Skarda RT, Milne DW. Estimation of cardiac output in the horse by thermodilution techniques.. Am J Vet Res 1976 Jun;37(6):697-700.
          pubmed: 779541
        31. Steffey EP, Dunlop CI, Farver TB, Woliner MJ, Schultz LJ. Cardiovascular and respiratory measurements in awake and isoflurane-anesthetized horses.. Am J Vet Res 1987 Jan;48(1):7-12.
          pubmed: 3826845
        32. Taylor PM. Equine stress responses to anaesthesia.. Br J Anaesth 1989 Dec;63(6):702-9.
          pubmed: 2692673doi: 10.1093/bja/63.6.702google scholar: lookup
        33. Steffey EP, Howland D Jr, Giri S, Eger EI 2nd. Enflurane, halothane, and isoflurane potency in horses.. Am J Vet Res 1977 Jul;38(7):1037-9.
          pubmed: 883711
        34. Hildebrand SV, Holland M, Copland VS, Daunt D, Brock N. Clinical use of the neuromuscular blocking agents atracurium and pancuronium for equine anesthesia.. J Am Vet Med Assoc 1989 Jul 15;195(2):212-9.
          pubmed: 2768037
        35. NAHAS GG, CAVERT HM. Cardiac depressant effect of CO2 and its reversal.. Am J Physiol 1957 Sep;190(3):483-91.
          pubmed: 13470078doi: 10.1152/ajplegacy.1957.190.3.483google scholar: lookup
        36. Gregory GA, Eger EI, Smith NT, Cullen BF. The cardiovascular effects of carbon dioxide in man awake and during diethyl ether anesthesia.. Anesthesiology 1974 Mar;40(3):301-4.
          pubmed: 4814253doi: 10.1097/00000542-197403000-00022google scholar: lookup
        37. Hodgson DS, Steffey EP, Grandy JL, Woliner MJ. Effects of spontaneous, assisted, and controlled ventilatory modes in halothane-anesthetized geldings.. Am J Vet Res 1986 May;47(5):992-6.
          pubmed: 3717746
        38. Gillespie JR, Tyler WS, Hall LW. Cardiopulmonary dysfunction in anesthetized, laterally recumbent horses.. Am J Vet Res 1969 Jan;30(1):61-72.
          pubmed: 5782568
        39. Steffey EP, Kelly AB, Woliner MJ. Time-related responses of spontaneously breathing, laterally recumbent horses to prolonged anesthesia with halothane.. Am J Vet Res 1987 Jun;48(6):952-7.
          pubmed: 3605811
        40. Hall LW, Gillespie JR, Tyler WS. Alveolar-arterial oxygen tension differences in anaesthetized horses.. Br J Anaesth 1968 Aug;40(8):560-8.
          pubmed: 4875426doi: 10.1093/bja/40.8.560google scholar: lookup
        41. Meyer RE, Short CE. Arterial to end-tidal CO2 tension and alveolar dead space in halothane- or isoflurane-anesthetized ponies.. Am J Vet Res 1985 Mar;46(3):597-9.
          pubmed: 3922264

        Citations

        This article has been cited 5 times.
        1. Stefanik E, Drewnowska O, Lisowska B, Turek B. Causes, Effects and Methods of Monitoring Gas Exchange Disturbances during Equine General Anaesthesia. Animals (Basel) 2021 Jul 9;11(7).
          doi: 10.3390/ani11072049pubmed: 34359177google scholar: lookup
        2. Vengust M. Hypercapnic respiratory acidosis: a protective or harmful strategy for critically ill newborn foals?. Can J Vet Res 2012 Oct;76(4):275-80.
          pubmed: 23543953
        3. Kerr CL, McDonell WN, Young SS. Cardiopulmonary effects of romifidine/ketamine or xylazine/ketamine when used for short duration anesthesia in the horse. Can J Vet Res 2004 Oct;68(4):274-82.
          pubmed: 15581222
        4. Lambertini C, Boanini E, Casalini I, Spaccini F, Rinnovati R, Romagnoli N. Comparison of Ketamine/Diazepam and Tiletamine/Zolazepam Combinations for Anaesthesia Induction in Horses Undergoing Partial Intravenous Anaesthesia (PIVA): A Retrospective Clinical Study. Vet Sci 2024 Nov 30;11(12).
          doi: 10.3390/vetsci11120612pubmed: 39728952google scholar: lookup
        5. Bukoski A, Downs J, Hodgson DS, Le-Bert CR, Thomen R, Flors L, Thombs L, Bailey J. Cardiopulmonary effects of apneustic anesthesia ventilation in anesthetized pigs: a new mode of ventilation for anesthetized veterinary species. Front Vet Sci 2024;11:1378617.
          doi: 10.3389/fvets.2024.1378617pubmed: 38855412google scholar: lookup
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