Table 2.

Physiological measurements of horses during rest and exercise

Variable Rest ExerciseRecovery, 1 h Furosemiden
Rest Exercise
PaO2, Torr 96.2 ± 3.684.6 ± 3.2 95.0 ± 5.0 88.4 ± 6.385.3 ± 11.5 4
PaCO2, Torr45.0 ± 1.6 46.0 ± 2.3 40.9 ± 1.0* 44.9 ± 2.5 46.3 ± 4.2 4
pHa 7.44 ± 0.01 7.25 ± 0.06 7.44 ± 0.017.48 ± 0.01 7.30 ± 0.05 4
Pv̅ O2, Torr36.5 ± 3.3 21.5 ± 2.0 38.5 ± 1.735.7 ± 2.6 22.1 ± 1.3 5
Pv̅ CO2, Torr50.9 ± 2.4 99.9 ± 15.4 46.8 ± 1.3* 50.2 ± 2.9 98.4 ± 17.6 5
pH 7.40 ± 0.027.14 ± 0.07 7.41 ± 0.017.45 ± 0.01 7.19 ± 0.05 5
CaO2, ml/dl 18.3 ± 3.026.3 ± 2.6 19.6 ± 2.6 19.4 ± 2.527.9 ± 2.6 4
Cv̅ O2, ml/dl12.8 ± 3.2 3.6 ± 1.2 14.6 ± 2.213.6 ± 2.8 4.4 ± 0.9 4
o 2, ml ⋅ min−1 ⋅ kg−1 5.2 ± 0.8 140.5 ± 20.9 5.6 ± 0.44.9 ± 0.6 149.4 ± 29.0 4
co 2, ml ⋅ min−1 ⋅ kg−1 4.5 ± 0.8 155.4 ± 18.6 4.5 ± 0.44.0 ± 0.4 163.9 ± 28.5 4
RER0.86 ± 0.05 1.11 ± 0.05 0.81 ± 0.090.81 ± 0.10 1.10 ± 0.04 4
Cardiac output, ml ⋅ min−1 ⋅ kg−1 97.4 ± 21.4 616.9 ± 64.1118.7 ± 33.1 85.6 ± 16.7632.8 ± 96.4 4
Cardiac output, l/min46.1 ± 8.3 292.4 ± 10.2 57.2 ± 19.938.6 ± 5.0 286.4 ± 19.9 4
Ppa, mmHg27.7 ± 2.4 83.2 ± 11.5 30.9 ± 3.524.1 ± 1.5 77.6 ± 13.4 5
HR, beats/min 38.1 ± 5.2 208.9 ± 9.240.6 ± 5.7 34.7 ± 6.4 203.7 ± 13.15
SV, liters 1.23 ± 0.26 1.38 ± 0.071.37 ± 0.29 1.19 ± 0.22 1.38 ± 0.114
SV, ml/kg 2.60 ± 0.63 2.92 ± 0.312.86 ± 0.39 2.62 ± 0.54 3.04 ± 0.484
PCV, % 39.2 ± 7.6 57.2 ± 6.542.4 ± 4.5 42.4 ± 5.3 61.0 ± 6.65
Lactate, mmol/l 1.01 ± 0.3618.57 ± 5.13 3.55 ± 1.96* 1.02 ± 0.11 16.98 ± 2.58 5
Body temperature, °C 37.7 ± 0.3 40.6 ± 0.537.9 ± 0.2 37.7 ± 0.2 40.6 ± 0.75
Body weight, kg 472 ± 34452 ± 38 5
  • Values are means ± SD; n = no. of horses. See text for differences in observations. PaO2 and PaCO2, arterial Po 2and Pco 2, respectively; pHa, arterial pH; Pv̅ O2 and Pv̅ CO2, mixed venous Po 2 and Pco 2, respectively; pH, mixed venous pH; CaO2, O2 content in arterial blood; Cv̅ O2, O2 content in mixed venous blood;V˙o 2, O2consumption; V˙co 2, CO2 elimination; RER, respiratory exchange ratio; Ppa, mean pulmonary arterial pressure; HR, heart rate; SV, stroke volume; PCV, packed cell volume.

  • * Resting value before furosemide is significantly different from recovery value, P ≤ 0.05;

  • resting value after furosemide is significantly different from resting value before furosemide;

  • exercise value after furosemide is significantly different from exercise value before furosemide.