Acid-base indicators in the venous and arterial blood of horses affected by recurrent airway obstruction (RAO)

Abstract

The acid-base equilibrium is closely linked to gas exchange in the lungs, and respiratory exchange ratios are used to evaluate respiratory effectiveness and tissue oxygen levels. Acid-base indicators are determined in both arterial and venous blood samples. This study compares the usefulness of acid-base indicators of venous and arterial blood in monitoring the condition of horses with recurrent airway obstruction. Prior to treatment involving bronchodilating glucocorticoids, expectorant and mucolytic drugs, more pronounced changes were observed in venous blood (pH 7.283, pCO 2 61.92 mmHg, pO 2 35.541 mmHg, HCO 3-31.933 mmHg, BE 2.933 mmol/l, O 2 SAT 58.366%, ctCO 2 38.333 mmol/l) than in arterial blood (pH 7.309, pCO 2 53.478 mmHg, pO 2 90.856 mmHg, HCO 3-28.50 mmHg, BE 3.133 mmol/l, O 2 SAT 93.375%, ctCO 2 31.652 mmol/l), indicating compensated respiratory acidosis. The improvement of respiratory efficiency minimized acidosis symptoms in both venous blood (pH 7.365, pCO 2 43.55 mmHg, pO 2 47.80 mmHg, HCO 3-30.325 mmHg, BE 3.050 mmol/l, O 2 SAT 80.10%, ctCO 2 29.80 mmol/l) and arterial blood (pH 7.375, pCO 2 39.268 mmHg, pO 2 98.476 mmHg, HCO 3-26.651 mmHg, BE 4.956 mmol/l, O 2 SAT 98.475%, ctCO 2 28.131 mmol/l). Venous blood parameters were marked by greater deviations from mean values, both before and after treatment. Acid-base indicators determined in venous blood are indicative of respiratory disturbances, but they do not support a comprehensive evaluation of gas exchange in the lungs.

Oxidant‐Antioxidant Status in the Blood of Horses with Symptomatic Recurrent Airway Obstruction (RAO)

“…Disease exacerbation induced by the poor environmental conditions was confirmed by clinical examination, a modified clinical RAO score and an endoscopic examination as defined previously (see Appendix ), together with cytology of the bronchoalveolar lavage fluid (BALF) and arterial blood gas analysis . Venous blood was additionally obtained to rule out evidence of pulmonary infection, based on blood count and acute phase protein concentration . A score of less than 10% of neutrophils in BALF was required for healthy horses, whereas >50% neutrophils on a differential cell count after environmental challenge was required to define RAO‐affected horses in crisis.…”

“…15 Venous blood was additionally obtained to rule out evidence of pulmonary infection, based on blood count and acute phase protein concentration. 16,17 A score of less than 10% of neutrophils in BALF was required for healthy horses, whereas >50% neutrophils on a differential cell count after environmental challenge was required to define RAO-affected horses in crisis.…”

Neutrophil and macrophage apoptosis in bronchoalveolar lavage fluid from healthy horses and horses with recurrent airway obstruction (RAO)

“…The blood was immediately analyzed for the partial pressure of oxygen and carbon dioxide (PaO 2 and PaCO 2 ) with the use of an OPTI CCA-TS (OPTI Medical Systems, Inc., Roswell, GA, USA) blood gas analyzer. Horses were identified as healthy, if their PaO2 ≥ 90 mmHg, while horses with a relapse of RAO had to have a PaO2 ≤ 85 mmHg [16,17]. …”

Recurrent respiratory disorders in Polish Konik horses - clinical and laboratory findings

“…Arterial blood was anaerobically collected in heparinised syringes by arterial puncture of the facial artery through a 20G butterfly catheter. The blood was immediately analysed for pH, partial pressure of carbon dioxide (pCO 2 ), and partial pressure of oxygen (pO 2 ) (17). A blood gas analyser OPTI CCA-TS (OPTI Medical Systems, Inc., Roswell, USA) was used.…”