Do heart and respiratory rate variability improve prediction of extubation outcomes in critically ill patients?

Table 2 Statistically significant comparisons of during spontaneous breathing trial (SBT) variability

Variability domain	Measure name	Passed (n = 383)	Failed (n = 51)	P value
Statistical	HRV Mean of the differences	1.4 10⁻⁶ (−9.4 10⁻⁷, 3.7 10⁻⁶)	−8.4 10⁻⁶ (−1.5 10⁻⁵, −1.9 10⁻⁶)	0.00278
Geometric	RRV Recurrence quantification analysis: average diagonal line	0.0057 (0.0054, 0.0060)	0.0044 (0.0038, 0.0053)	0.00011
	RRV Recurrence quantification analysis: maximum diagonal line	0.021 (0.020, 0.022)	0.016 (0.015, 0.018)	0.00004
	RRV Recurrence quantification analysis: maximum vertical line	0.017 (0.016, 0.018)	0.012 (0.011, 0.014)	0.00017
	RRV Recurrence quantification analysis: trapping time	0.0048 (0.0046, 0.0050)	0.0038 (0.0030, 0.0042)	0.00009
Informational	RRV Fano factor distance from a Poisson distribution	−0.12 (−0.12, −0.11)	−0.15 (−0.17, −0.12)	0.00166
Energetic	RRV Hjorth parameters: activity	11.1 (10.4, 11.8)	7.8 (6.0, 10.7)	0.00406
Invariant	HRV Power Law (based on frequency) x intercept	15.8 (14.8, 17.3)	10.0 (4.5, 13.9)	0.00255
	RRV Largest Lyapunov exponent	1.02 (1.00, 1.02)	1.07 (1.03, 1.14)	0.00151
	RRV Power Law (based on histogram) y intercept	−2.17 (−2.21, −2.10)	−2.35 (−2.59, −2.15)	0.00259

For specific details about each measure, refer to [28]. HRV, heart rate variability; RRV, respiratory rate variability.

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