Resumo

GUERRA, Marcelle et al. Cardiac autonomic modulation during different modes of weaning of mechanical ventilation. J. Hum. Growth Dev. [online]. 2019, vol.29, n.2, pp. 232-240. ISSN 0104-1282.  http://dx.doi.org/10.7322/jhgd.v29.9427.

INTRODUCTION: Heart rate variability (HRV) is a noninvasive method to analyze variations of time intervals between heart beats. HRV is a promising method to analyze autonomic balance quantitatively. During the weaning process of mechanical ventilation, alterations occur in the autonomic activity. Methods to identify increased risk for weaning failure are needed. OBJECTIVE: To analyze the behavior of cardiac autonomic modulation in different phases of weaning mechanical ventilation. METHODS: Cardiorespiratory parameters (SBP, DBP, MAP, RR, SpO2) of 18 participants were collected and a cardio-frequency meter was placed. The subjects were kept in supine Fowler's position t, ventilating for 10 minutes in the assist-controlled (A/C) ventilation mode the synchronized intermittent mandatory ventilation (SIMV) mode, pressure support ventilation (PSV) 18 and 10, and with nebulization through a T-piece. At the end of all ventilator modes, the pre-specified variables were measured. The HRV parameters were analyzed in the domains of time, frequency and geometric indexes. RESULTS: There was an increase in the mean rMSSD of the A/C moment of 20.67 ± 19.36ms for the PSV 10 time 29.96 ± 21.26ms (p = 0.027), increase between the SIMV moments of 24.04 ± 18.31ms and PSV 10 to 29.96 ± 21.26ms (p = 0.042), but reduced between PSV 10 and T-Tube moments 21.22 ± 13.84ms (p = 0.035). There was an increase in the LF mean of the SIMV moments 158.46 ± 229.77ms2 and PSV 10 265.50 ± 359.88ms2 for T-tube 408.92 ± 392.77ms2 (p = 0.011 and p = 0.037 respectively). The mean LF showed a decrease between C/A and SIMV moments, respectively, 62.48 ± 17.99nu and 54.29 ± 15.29nu (p = 0.024), increase in SIMV moments 54.29 ± 15.29nu and PSV 10 55.05 ± 23.07nu for TUBE T 65.57 ± 17.08nu (p = 0.049 and p = 0.027 respectively). HF increased between SIMV moments 162.89 ± 231.19ms2 and PSV 10 247.83 ± 288.99ms2 (p = 0.020) and also between SIMV and T-Tube moments 248.28 ± 214.46 ms2 (p = 0.044). There was a reduction in mean HF between PSV 10 times 44.71 ± 22.95nu and T-tube 34.22 ± 17.03nu (p = 0.026 CONCLUSIONS: The present study showed that in comparison with spontaneous breathing, controlled breathing was associated with lower HRV during weaning from mechanical ventilation.

Palavras-chave : autonomic nervous system; heart rate of weaning; ventilatory weaning.

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