48-Hour Fluid Balance Does Not Predict a Successful Spontaneous Breathing Trial.
BACKGROUND
Both premature and delayed liberation from mechanical ventilation are associated with increased morbidity and mortality, and fluid balance could negatively influence extubation outcomes. We sought to determine the impact of fluid balance in the 48 h before a spontaneous breathing trial (SBT) on weaning outcomes in a mixed ICU population.


METHODS
This was a prospective observational study in 2 adult medical-surgical ICUs. All enrolled subjects met eligibility criteria for weaning from mechanical ventilation. SBT failure was defined as inability to tolerate a T-piece trial for 30-120 min. Data on demographics, physiology, fluid balance in the 48 h preceding SBT (fluid input minus output over the 48-h period), lung ultrasound findings, and outcomes were collected.


RESULTS
Of a total of 250 SBTs, SBT failure eventuated in 51 (20.4%). Twenty-nine subjects (11.6%) had COPD, and 40 subjects (16%) were intubated due to respiratory sepsis. One-hundred eighty-nine subjects (75.6%) were extubated on the first attempt. Compared with subjects with SBT success, SBT failure subjects were younger (median of 66 vs. 75 y, P = .001) and had a higher duration of mechanical ventilation (median of 7 vs. 4 d, P < .001) and a higher prevalence of COPD (19.6 vs. 9.5%, P = .04). There were no statistically significant differences in 48-h fluid balance before SBT between groups (SBT failure, 1,201.65 ± 2,801.68 mL; SBT success, 1,324.39 ± 2,915.95 mL). However, in the COPD subgroup, we found a significant association between positive fluid balance in the 48 h before SBT and SBT failure (odds ratio of 1.77 [1.24-2.53], P = .04).


CONCLUSIONS
Fluid balance should not delay SBT indication because it does not predict greater probability of SBT failure in the medical-surgical critically ill population. Notwithstanding, avoiding positive fluid balance in patients with COPD might improve weaning outcomes. (ClinicalTrials.gov registration NCT02022839.).
Adult Intensive Care Unit, Hospital Moinhos de Vento, Porto Alegre, Brazil. Adult Intensive Care Unit, Hospital Mãe de Deus and Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil. ana.carolina.antonio@gmail.com.
Ana Carolina Peçanha
AC
Antonio
Adult Intensive Care Unit, Hospital Moinhos de Vento, Porto Alegre, Brazil.
Cassiano
C
Teixeira
Adult Intensive Care Unit, Hospital Moinhos de Vento, Porto Alegre, Brazil. Adult Intensive Care Unit, Hospital Mãe de Deus and Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.
Priscylla Souza
PS
Castro
Adult Intensive Care Unit, Hospital Moinhos de Vento, Porto Alegre, Brazil.
Augusto
A
Savi
Adult Intensive Care Unit, Hospital Moinhos de Vento, Porto Alegre, Brazil.
Roselaine Pinheiro
RP
Oliveira
Adult Intensive Care Unit, Hospital Moinhos de Vento, Porto Alegre, Brazil.
Marcelo Basso
MB
Gazzana
Postgraduate Program in Pneumology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Marli
M
Knorst
D000368:Aged; D000369:Aged, 80 and over; D060666:Airway Extubation / Q000009:adverse effects* / Q000379:methods; D016638:Critical Illness / Q000628:therapy; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000378:metabolism; D012119:Respiration; D013997:Time Factors; D017211:Treatment Failure; D014463:Ultrasonography; D015300:Ventilator Weaning / Q000009:adverse effects* / Q000379:methods / Q000706:statistics & numerical data; D014882:Water-Electrolyte Balance / Q000502:physiology*
cardiac failure; chronic obstructive pulmonary disease; fluid balance; ventilator weaning