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Table 3 Oxygen variables from isoflurane-anesthetized horses (n = 5) breathing 50% or maximal oxygen concentrations

From: Effect of 50% and maximal inspired oxygen concentrations on respiratory variables in isoflurane-anesthetized horses

Parameter FiO2 -5 min 15 min 30 min 60 min 90 min 120 min 150 min 180 min +10 min Stand + 30 min
CaO2 (mL/dL) 50% 17.9 ± 2.1 16.7 ± 0.5 16.4 ± 0.7 19.3 ± 0.3 18.7 ± 0.3 18.3 ± 0.7 17.4 ± 1.1 16.9 ± 1.0 14.4 ± 0.4 16.2 ± 0.6
  >95% 16.4 ± 0.7 17.0 ± 0.5 18.3 ± 1.0 19.4 ± 1.2 19.4 ± 0.6 19.1 ± 0.7 19.2 ± 1.1 18.6 ± 1.2 14.3 ± 0.8 15.4 ± 0.6
CvO2 (mL/dL) 50% 13.0 ± 1.7 13.1 ± 0.6 13.2 ± 0.5 16.9 ± 0.6 16.6 ± 0.3 15.5 ± 0.9 14.9 ± 1.5 14.1 ± 1.3 9.9 ± 0.7 10.2 ± 0.7
  >95% 11.3 ± 0.5 14.3 ± 0.5 15.1 ± 1.0 16.5 ± 1.4 16.4 ± 1.2 15.9 ± 1.3 15.4 ± 1.3 14.7 ± 1.3 9.7 ± 0.8 9.3 ± 1.2
O2ER (%) 50% 27 ± 4 22 ± 2 19 ± 3 12 ± 3 11 ± 1 15 ± 3 15 ± 4 17 ± 3 32 ± 3 37 ± 4
  >95% 31 ± 1 16 ± 2 18 ± 4 15 ± 3 16 ± 4 17 ± 5 20 ± 3 21 ± 3 32 ± 3 40 ± 6
VO2 (mL/kg bwt/min) 50% 2.9 ± 1 1.5 ± 0.2 1.4 ± 0.2 1.1 ± 0.2a 1.1 ± 0.1a 1.0 ± 0.1a 0.9 ± 0.1a 1.0 ± 0.1a 1.4 ± 0.1 3.5 ± 0.5
  >95% 2.8 ± 0.2 1.0 ± 0.1a 1.3 ± 0.2 1.4 ± 0.2 1.1 ± 0.2 1.2 ± 0.2 1.3 ± 0.1 1.3 ± 0.1 1.6 ± 0.1 4.0 ± 0.8
C(a-v)O2 (mL/dL) 50% 4.87 ± 0.79 3.61 ± 0.40 3.20 ± 0.59 2.34 ± 0.49 2.12 ± 0.29 2.77 ± 0.48 2.53 ± 0.56 2.73 ± 0.38 4.52 ± 0.28 5.93 ± 0.65
  >95% 5.12 ± 0.32 2.75 ± 0.40 3.28 ± 0.65 2.86 ± 0.49 3.00 ± 0.74 3.18 ± 0.84 3.75 ± 0.52 3.83 ± 0.46 4.61 ± 0.51 6.08 ± 0.80
PaO2-IO2 ratio 50% 0.64 ± 0.05 0.27 ± 0.03a 0.28 ± 0.02a 0.30 ± 0.02a 0.29 ± 0.03a 0.27 ± 0.03a 0.23 ± 0.03a 0.22 ± 0.03a 0.30 ± 0.01a 0.64 ± 0.02
  >95% 0.64 ± 0.03 0.41 ± 0.05 0.36 ± 0.05a 0.41 ± 0.07 0.38 ± 0.06a 0.35 ± 0.07a 0.32 ± 0.07a 0.32 ± 0.07a 0.32 ± 0.02a 0.55 ± 0.06
P(A-a)O2 (kPa) 50% 1.84 ± 1.09 27.51 ± 2.07a,b 27.12 ± 1.00a,b 26.52 ± 1.05a,b 26.79 ± 1.29a,b 27.85 ± 1.23a,b 30.26 ± 1.60a,b 29.81 ± 1.44a,b 5.99 ± 0.67 0.99 ± 0.20
  >95% 1.20 ± 0.31 45.93 ± 3.90a,b 51.07 ± 4.51a,b 46.77 ± 5.97a,b 49.22 ± 5.26a,b 52.08 ± 6.38a,b 54.36 ± 6.31a,b 55.33 ± 6.48a,b 5.74 ± 0.90 2.40 ± 1.04
DO2 (mL/kg bwt/min) 50% 10.82 ± 3.59 6.84 ± 0.60 7.44 ± 0.84 9.82 ± 0.85 9.91 ± 0.94 7.48 ± 1.07 6.71 ± 1.00 6.24 ± 0.61 4.62 ± 0.26a 9.47 ± 0.78
  >95% 9.16 ± 1.00 6.26 ± 0.24 7.24 ± 0.49 9.55 ± 0.89 8.34 ± 1.19 7.91 ± 1.03 6.65 ± 0.50 6.47 ± 0.44 5.11 ± 0.41 10.20 ± 1.19
Qs/Qt (%) 50% 13 ± 2 28 ± 4 30 ± 5 39 ± 8a 40 ± 6a 36 ± 4 40 ± 4a 40 ± 3a 43 ± 4a 9 ± 1
  >95% 9 ± 1 35 ± 4a 36 ± 6a 36 ± 4a 38 ± 5a 37 ± 4a 33 ± 3a 32 ± 3 38 ± 5a 12 ± 2
Vd/Vt (%) 50% ----- 11.9 ± 4.4 11.7 ± 1.3 17.6 ± 1.5 19.4 ± 2.6 19.4 ± 3.1 20.5 ± 2.4 27.2 ± 3.9c ----- -----
  >95% ----- 13.6 ± 3.2 17.7 ± 1.9 16.4 ± 2.2 18.7 ± 3.8 23.4 ± 2.3 27.6 ± 2.3 29.2 ± 2.2c ----- -----
  1. Data are presented as mean ± standard error of the mean. CaO2, arterial oxygen content; CvO2, venous oxygen content; O2ER, oxygen extraction ratio; VO2, oxygen consumption; C(a-v)O2, oxygen content difference; PaO2-IO2 ratio, arterial oxygen tension to inspired oxygen tension ratio; P(A-a)O2, alveolar arterial oxygen tension difference; DO2, oxygen delivery; Qs/Qt, shunt fraction; Vd/Vt, alveolar dead space. Time points: -5, 15, 30, 60, 90, 120, 150, and 180 represent min prior to and after induction of anesthesia; +10 min represents 10 min after disconnection from the anesthesia machine; and Stand +30 min represents 30 min after the horses stood in recovery.
  2. a Within a treatment, value is significantly different than the -5 min value for this variable.
  3. b Within this time point, value is significantly different than other treatment
  4. c With a treatment, value is significantly different from the 15 min value for this variable