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Table 3 Measurements of MEWS, vital signs and heart rate variability of study patients

From: Prediction of cardiac arrest in critically ill patients presenting to the emergency department using a machine learning score incorporating heart rate variability compared with the modified early warning score

Variable

No cardiac arrest within 72 hours (n= 882)

Cardiac arrest within 72 hours (n= 43)

P valuea

No death (n= 839)

Death (n= 86)

P valuea

Age

61 (16)

66 (16)

0.047

61 (16)

69 (16)

< 0.001

Vital signs

      

   Glasgow Coma Scale

15 (15 to 15)

15 (11 to 15)

0.002

15 (15 to 15)

15 (10 to 15)

< 0.001

   Temperature (°C)

37 (1)

37 (1)

0.118

37 (1)

37 (1)

0.280

   Pulse rate (beats/minute)

96 (30)

106 (25)

0.026

96 (30)

102 (25)

0.055

   Respiratory rate (breaths/minute)

19 (5)

20 (5)

0.040

19 (5)

20 (5)

0.021

   Systolic BP (mmHg)

136 (38)

125 (34)

0.082

136 (37.899)

130 (40.761)

0.207

   Diastolic BP (mmHg)

77 (22)

75 (20)

0.460

78 (21)

73 (23)

0.076

   Oxygen saturation (%)

96 (6)

93 (13)

< 0.001

96 (6)

94 (9)

0.001

   Pain score

0 (0 to 3)

0 (0 to 3)

0.825

0 (0 to 3)

0 (0 to 0)

0.010

HRV variables

      

   aRR (s)

0.718 (0.177)

0.621 (0.149)

< 0.001

0.721 (0.175)

0.644 (0.176)

< 0.001

   STD (s)

0.053 (0.033)

0.057 (0.047)

0.490

0.054 (0.033)

0.051 (0.044)

0.534

   avHR (beats/minute)

89.004 (20.566)

102.692 (22.136)

< 0.001

88.582 (20.317)

99.971 (22.975)

< 0.001

   sdHR (beats/minute)

6.463 (3.740)

8.152 (5.531)

0.005

6.473 (3.731)

7.204 (4.877)

0.094

   RMSSD (ms)

0.039 (0.041)

0.048 (0.054)

0.272

0.038 (0.039)

0.048 (0.063)

0.184

   nn50 (count)

571 (1,268)

484 (748)

0.655

547 (1,178)

765 (1,800)

0.123

   pnn50

7.048 (12.268)

6.561 (9.667)

0.797

6.878 (11.773)

8.460 (15.411)

0.251

   RR triangular index

2.475 (1.000)

2.046 (0.736)

0.006

2.486 (1.000)

2.158 (0.840)

0.004

   TINN (ms)

0.217 (0.130)

0.189 (0.148)

0.170

0.219 (0.130)

0.184(0.142)

0.017

   VLF power (ms2)

0.131 (0.102)

0.099 (0.084)

0.045

0.133 (0.101)

0.098 (0.097)

0.002

   LF power (ms2)

0.057 (0.042)

0.056 (0.045)

0.876

0.058 (0.043)

0.053 (0.040)

0.319

   HF power (ms2)

0.080 (0.070)

0.103 (0.083)

0.032

0.079 (0.070)

0.100(0.077)

0.008

   Total power (ms2)

0.268 (0.135)

0.259 (0.131)

0.673

0.269 (0.135)

0.251 (0.137)

0.223

   LF power (nu)

45.430 (18.489)

36.459 (15.798)

0.002

45.938 (18.586)

35.990 (14.452)

< 0.001

   HF power (nu)

54.566 (18.487)

63.541 (15.798)

0.002

54.058 (18.583)

64.010 (14.452)

< 0.001

   LF/HF ratio

1.205 (1.284)

0.802 (1.171)

0.043

1.232 (1.299)

0.742 (0.992)

0.001

MEWS

2 (1 to 4)

4 (2 to 5)

< 0.001

2 (1 to 4)

4 (2 to 5)

< 0.001

  1. Data shown are mean (standard deviation) or median (interquartile range, 25th to 75th percentiles). BP, blood pressure; HRV, heart rate variability; MEWS, modified early warning score. aP value from either an unpaired t test or the Mann-Whitney test as appropriate.