RESUMO
Background: The effect of a single isometric handgrip exercise (IHG) on blood pressure (BP) variability (BPV) has not been addressed. This randomized controlled trial evaluated the effect of IHG vs. sham on BPV and BP. Methods: Hypertensive patients using up to two BP-lowering medications were randomly assigned to IHG (4 × 2 min; 30% of maximal voluntary contraction, MVC, with 1 min rest between sets, unilateral) or sham (protocol; 0.3% of MVC). Systolic and diastolic BP were assessed beat-to-beat in the laboratory before, during, and post-intervention and also using 24-h ambulatory BP monitoring (ABPM). BPV was expressed as average real variability (ARV) and standard deviation (SD). Results: Laboratory BPV, ARV and SD variability, had marked increase during the intervention, but not in the sham group, decreasing in the post-intervention recovery period. The overall change in ARV from pre- to 15 min post-intervention were 0.27 ± 0.07 (IHG) vs. 0.05 ± 0.15 (sham group), with a statistically significant p-value for interaction. Similarly, mean systolic BP increased during the intervention (IHG 165.4 ± 4.5 vs. sham 152.4 ± 3.5 mmHg; p = 0.02) as did diastolic BP (104.0 ± 2.5 vs. 90.5 ± 1.7 mmHg, respectively; p < 0.001) and decreased afterward. However, neither the short-term BPV nor BP assessed by ABPM reached statistically significant differences between groups. Conclusion: A single session of IHG reduces very short-term variability but does not affect short-term variability. IHG promotes PEH in the laboratory, but does not sustain 24-h systolic and diastolic PEH beyond the recovery period.
RESUMO
BACKGROUND: Handgrip strength is an alternative measure to assess peripheral muscle strength and is correlated with the Medical Research Council (MRC) scale, with promising values for diagnosing ICU-acquired weakness (ICUAW). Because ICUAW has been associated with delayed weaning from mechanical ventilation, we hypothesized that ICUAW evaluated with both the MRC scale score and handgrip strength are associated with failure of a spontaneous breathing trial (SBT) and duration of mechanical ventilation weaning. METHODS: We conducted a prospective observational study in 3 general ICUs with a total of 54 beds at 2 academic hospitals. Adult subjects with > 48 h of mechanical ventilation who were eligible for weaning were included in the study. RESULTS: In the evaluation before the first SBT, the MRC score (P < .001) and handgrip strength (P < .001) were significantly different between subjects extubated after a successful first SBT (simple weaning) and those extubated any time after a failed first SBT (difficult weaning). Only the MRC score discriminated between first SBT success or failure (P < .001); in multivariate analysis, the MRC score was significantly associated with first SBT failure (odds ratio 0.91, 95% CI 0.88-0.97, P < .001) and difficult weaning (odds ratio 0.91, 95% CI 0.87-0.96, P < .001). Handgrip strength exhibited good accuracy in identifying ICUAW. CONCLUSIONS: MRC score was independently associated with SBT failure and difficult or prolonged weaning.