Table 2

Risks of having above-average outcomes after major spine surgery based on the analysis between threshold and outcome (n=102)

Parameters and thresholdsBeyond threshold
(n, total)
Length of hospital stay ≤6 days (n=61) vs
length of hospital stay >6 days (n=41)
Composite complications ≤3 (n=70) vs
composite complications >3 (n=32)
Beyond threshold
(n vs n)
RR (95% CI)Beyond threshold
(n vs n)
RR (95% CI)
MAP <50 mm Hg†3714 vs 232.04 (1.29 to 3.23)**20 vs 171.81 (1.03 to 3.16)*
MAP <60 mm Hg6129 vs 322.04 (1.11 to 3.76)*35 vs 262.49 (1.13 to 5.45)*
MAP <70 mm Hg8544 vs 41NE54 vs 314.01 (0.61 to 26.55)
MAP >100 mm Hg9051 vs 391.30 (0.41 to 4.13)60 vs 301.00 (0.31 to 3.22)
MAP >110 mm Hg7741 vs 361.78 (0.81 to 3.91)49 vs 281.73 (0.69 to 4.33)
MAP >120 mm Hg6936 vs 331.61 (0.86 to 3.03)43 vs 261.70 (0.79 to 3.66)
Temp <35°C4422 vs 221.53 (0.95 to 2.45)21 vs 233.37 (1.73 to 6.54)***
Temp <35.5°C7040 vs 301.25 (0.72 to 2.16)44 vs 261.98 (0.91 to 4.33)
Temp <36°C8550 vs 351.17 (0.58 to 2.33)57 vs 281.40 (0.56 to 3.47)
Temp >37°C2914 vs 151.45 (0.91 to 2.32)20 vs 90.99 (0.52 to 1.87)
Temp >37.5°C84 vs 4NE6 vs 2NE
Temp >38°C11 vs 0NE1 vs 0NE
SpO2<90%105 vs 51.28 (0.65 to 2.50)7 vs 30.95 (0.35 to 2.57)
SpO<95%167 vs 91.51 (0.91 to 2.52)11 vs 51.00 (0.45 to 2.20)
HR <40 bpm20 vs 2NE0 vs 2NE
HR <50 bpm2415 vs 90.91 (0.51 to 1.63)16 vs 81.08 (0.56 to 2.09)
HR <60 bpm5335 vs 180.72 (0.45 to 1.17)33 vs 201.54 (0.84 to 2.81)
HR >90 bpm239 vs 141.78 (1.14 to 2.79)*16 vs 70.96 (0.48 to 1.93)
HR >100 bpm187 vs 111.71 (1.07 to 2.73)*13 vs 50.86 (0.39 to 1.94)
HR >110 bpm146 vs 81.52 (0.90 to 2.58)10 vs 40.90 (0.37 to 2.17)
PI <0.54019 vs 211.63 (1.02 to 2.59)*27 vs 131.06 (0.59 to 1.90)
PI <16538 vs 271.10 (0.66 to 1.82)47 vs 180.73 (0.41 to 1.29)
PI >62514 vs 111.13 (0.67 to 1.91)15 vs 101.40 (0.77 to 2.54)
PI >1033 vs 0NE0 vs 3NE
iVt <5 mL/kg10161 vs 40NE69 vs 32NE
iVt <6 mL/kg10161 vs 40NE69 vs 32NE
iVt >8 mL/kg10 vs 1NE1 vs 0NE
iVt >9 mL/kg10 vs 1NE1 vs 0NE
iVt >10 mL/kg00 vs 0NE0 vs 0NE
aVt <5 mL/kg7945 vs 341.41 (0.73 to 2.76)52 vs 271.57 (0.68 to 3.62)
aVt <6 mL/kg9455 vs 39NE64 vs 30NE
aVt >8 mL/kg3218 vs 141.13 (0.69 to 1.85)20 vs 121.31 (0.73 to 2.35)
aVt >9 mL/kg1910 vs 91.23 (0.71 to 2.12)12 vs 71.22 (0.62 to 2.40)
aVt >10 mL/kg118 vs 30.65 (0.24 to 1.77)7 vs 41.18 (0.51 to 2.73)
Ppeak <10 cmH2O4627 vs 191.05 (0.65 to 1.69)28 vs 181.57 (0.88 to 2.79)
Ppeak <15 cmH2O6839 vs 291.21 (0.71 to 2.06)46 vs 221.10 (0.59 to 2.05)
Ppeak >25 cmH2O3220 vs 120.91 (0.53 to 1.53)24 vs 80.73 (0.37 to 1.44)
Ppeak >30 cmH2O128 vs 40.81 (0.35 to 1.87)8 vs 41.07 (0.45 to 2.52)
Ppeak >35 cmH2O41 vs 3NE2 vs 2NE
PEEP <3 cmH2O5332 vs 210.97 (0.60 to 1.56)33 vs 201.54 (0.84 to 2.81)
PEEP >7 cmH2O1711 vs 60.86 (0.43 to 1.71)14 vs 30.52 (0.18 to 1.50)
PEEP >10 cmH2O63 vs 3NE5 vs 1NE
EtCO>25 mm Hg3922 vs 171.14 (0.71 to 1.84)26 vs 131.11 (0.62 to 1.98)
EtCO>30 mm Hg6234 vs 281.39 (0.82 to 2.35)39 vs 231.65 (0.85 to 3.19)
EtCO>40 mm Hg6339 vs 240.87 (0.54 to 1.41)44 vs 190.90 (0.51 to 1.62)
EtCO>45 mm Hg3421 vs 130.93 (0.56 to 1.55)23 vs 111.05 (0.57 to 1.91)
FiO<0.3563 vs 3NE4 vs 2NE
FiO<0.452113 vs 80.94 (0.51 to 1.17)12 vs 91.51 (0.83 to 2.76)
FiO>0.759657 vs 391.22 (0.38 to 3.88)65 vs 311.94 (0.32 to 11.87)
FiO>0.858652 vs 340.90 (0.49 to 1.67)58 vs 281.30 (0.53 to 3.21)
SctO<50%61 vs 5NE3 vs 3NE
SctO<55%134 vs 91.93 (1.22 to 3.04)*6 vs 71.92 (1.05 to 3.50)
SctO<60%2711 vs 161.78 (1.14 to 2.78)*15 vs 121.67 (0.95 to 2.93)
SctO>75%6845 vs 230.64 (0.40 to 1.01)48 vs 200.83 (0.46 to 1.50)
SctO>80%3724 vs 130.82 (0.49 to 1.37)25 vs 121.05 (0.58 to 1.90)
SctO>85%84 vs 4NE5 vs 3NE
SctO>90%20 vs 2NE1 vs 1NE
SstO<50%168 vs 81.30 (0.75 to 2.28)10 vs 61.24 (0.61 to 2.52)
SstO<55%2211 vs 111.33 (0.80 to 2.21)14 vs 81.21 (0.64 to 2.31)
SstO<60%3215 vs 171.55 (0.98 to 2.45)22 vs 100.99 (0.54 to 1.85)
SstO>75%8750 vs 371.59 (0.67 to 3.82)56 vs 315.34 (0.79 to 36.26)
SstO>80%7140 vs 311.35 (0.76 to 2.40)44 vs 272.36 (1.00 to 5.55)*
SstO>85%4523 vs 221.47 (0.91 to 2.35)26 vs 191.85 (1.02 to 3.33)*
SstO>90%95 vs 41.12 (0.52 to 2.42)5 vs 41.48 (0.67 to 3.26)
  • The physiological parameters were dichotomised based on whether the intraoperative measurements were beyond or not beyond the thresholds. The adverse outcome was defined as either length of hospital stay >6 days or composite complications >3.

  • *P<0.05; **P<0.01; ***P<0.001.

  • †n=96 for MAP due to missing invasive arterial blood pressure measurements.

  • aVt, tidal volume based on actual body weight; bpm, beats per minute; EtCO2, end- tidal carbon dioxide; FiO2, inspired oxygen fraction; HR, heart  rate; iVt, tidal volume based on ideal body weight; MAP, mean  arterial pressure; PEEP, positive  end-expiratory pressure; PI, perfusion  index; Ppeak, peak  airway pressure; SctO2 , cerebral tissue oxygen saturation; SpO2, pulse  oxygen saturation; SstO2, somatic  tissue oxygen saturation; RR, relative risk ; Temp, temperature; NE, not estimable.