Prolonged mechanical ventilation ups risk of extubation failure
Prolonged mechanical ventilation (MV) increases the risk of extubation failure in ICU patients, according to a recent Singapore study. Other independent risk factors include advanced age, high respiratory rate and low arterial pH.
“This study represents a snapshot of the clinical conditions immediately preceding extubation,” said researchers. “[I]t is prudent for physicians to weigh the risk of extubation failure against that of deterioration with further MV when making decisions on extubation.”
Of the 676 ICU patients (mean age, 61 years; 77 percent male) enrolled at the National University Hospital in Singapore, majority (n=601) experienced successful extubation; failure was reported in the remaining 75 participants. The latter group was older (mean age, 63 vs 60 years; p=0.025), more likely to have hypercapnia (24 percent vs 12 percent; p=0.005) and had lower arterial pH (p<0.001). [J Card Surg 2019;doi:10.1111/jocs.14189]
The median duration of MV was likewise significantly longer in patients whose extubation was unsuccessful (20 vs 13 hours; p<0.001).
Multivariate logistic regression analysis confirmed the significant role of a more advanced age (>65 years; odds ratio [OR], 1.27, 95 percent CI, 1.01–1.60; p=0.041), low arterial pH (<7.35 vs 7.35–7.45: OR, 2.15, 1.63–2.83; p<0.001) and prolonged MV (>12 hours; OR, 2.80, 1.93–4.03; p<0.001) in raising the risk of extubation failure.
Other significant predictors identified were respiratory rate >20 (OR, 1.43, 1.01–2.02; p=0.043), high heart rate (>100 vs 60–100 bpm; OR, 1.58, 1.13–2.17; p=0.006), low mean arterial pressure (MAP; <70 vs 70–105 mm Hg; OR, 1.66, 1.26–2.16; p<0.001) and high scores in the quick Sequential Organ Failure Assessment (qSOFA; OR, 2.80, 1.93–4.03; p<0.001).
“[S]ince a long duration of MV can also increase the risk of future extubation failure, physicians should not base their decision only on the current risk extubation failure,” they added. “The risk of deterioration with further MV should also be taken into consideration.”
In subsequent multivariate logistic regression models, age >65 years (OR, 0.84, 0.63–1.05; p=0.034), respiratory rate >20 (OR, 0.54, 0.41–0.71; p<0.001), MAP <106 mm Hg (OR, 1.27, 1.04–1.55; p=0.019), arterial pH <7.35 (OR, 1.36, 1.10–1.69; p=0.004) and high qSOFA scores (OR, 1.29, 1.06–1.58; p=0.013) remained significantly correlated with the risk of patient deterioration with continued MV.
Patients who suffered deterioration were also more likely to be on MV for >12 hours (27 percent vs 13 percent; p<0.001).
“The hope is that this study will serve as a basis for future research into the risk analysis of extubation failure vs deterioration with further MV,” said researchers, noting that “a prospective clinical trial on the decision to extubate based on the findings of this study would provide additional insights.”
“Moving forward, we will conduct further analysis of the trends of the patients’ clinical progression while intubated in the ICU to evaluate whether the rate of improvement has any bearing on extubation failure or deterioration with further MV,” they added.