DISCUSSION
critically ill, orthostasis
ADVERSE EVENTS, CRITICALLY ILL
The present crossover randomized clinical trial comparing the effect of passive
orthostasis using a tilt-table with a standard sitting position on lung aeration in
mechanically ventilated critical care patients found no difference between the
interventions. Although no difference in lung aeration was found between the
interventions, we cannot rule out the benefits or harms of passive orthostasis using
an orthostatic board. This is due to the inclusion of a smaller sample size than
needed to accept or refute our hypothesis. Thus, it does not provide sufficient
statistical power for definitive conclusions.The ventilatory benefits of vertical positioning in increasing the end-expiratory
lung volume and oxygenation of patients receiving IMV have already been
demonstrated.In the same context of mobilizing patients receiving IMV and assessing lung aeration,
Hickmann et al.We believe that the main factors involved in the lack of difference in lung aeration
between chest verticalization positions were as follows: first, the low power of the
present analysis due to the low number of participants might be associated with type
II error. The significant 95%CI found in the primary outcome analysis does not
exclude a benefit of passive orthostasis for lung aeration. Second, subjects showed
a median LUS of 10 points at baseline. Although the LUS does not have a cutoff point
for all populations and situations, Soummer et al.It has been shown that having a small number of multiprofessional staff members is a
constraint on the mobilization of critically ill patients.Our study had a higher rate of adverse events than reported in a large portion of the
literature.To the best of our knowledge, this is the first study to evaluate lung aeration in
different vertical positions by using the LUS in patients receiving IMV. Studies
using the LUS during vertical positioning in patients receiving other ventilation
support, such as high-flow nasal cannula (HFNC), noninvasive ventilation (NIV) or
IMV by tracheostomy, and evaluating the need for ventilatory support due to
pulmonary or extrapulmonary causes may bring new knowledge to clinical practice.Some limitations must be considered. First, just over 50% of the sample target was
met; however, the early interruption of the study was necessary due to the health
reality imposed by the COVID-19 pandemic. Second, assessment blinding was not
performed, and some evaluators were involved with the study, which may have led to
measurement bias. Third, in addition to the small sample, the study was limited to 2
hospitals, which may limit the external validity in other contexts. Fourth, the
study design may have led to a carry-over effect. Fifth, we cannot rule out temporal
alterations in the patients’ conditions, inherent to the clinical practice of the
intensive care environment.