Noninvasive Assessment of Weaning Failure from Mechanical Ventilation in Critically Ill Patients

*Mohamed Youssef Abd Elhamed
Department Of Critical Care Medicine, Faculty Of Medicine, Cairo University, Egypt

*Corresponding Author:
Mohamed Youssef Abd Elhamed
Department Of Critical Care Medicine, Faculty Of Medicine, Cairo University, Egypt

Published on: 2020-05-25

Abstract

Background: Weaning predictors are used as a point of decision to determine if a patient can progress to a spontaneous respiratory test.
Aim: The study aimed to evaluate the role of the following parameters: NT-proBNP, weaning indices (RSBI, Cst and IWI) and echocardiography with use of tissue Doppler imaging (left and right ventricular function was assessed by LVEF, the grade of mitral resurge if any, E/A, DT, E’, E/E’, TAPSE and RVFAC) as predictor tools of weaning failure in critically ill patients from mechanical ventilation.
Patients and Methods: This was a prospective study that was conducted on sixty adult patients of both sexes mechanically ventilated for more than 48 hours and who met the criteria of spontaneous breathing trial (SBT). The studied patients were recruited within a period between May 2016 and November 2017 from the Intensive Care Department in Theodor Bilharz Research Institute.
Results: Patients who failed SBT had a higher mortality rate compared to successful SBT. A patient who failed SBT showed a high incidence of weaning failure. Patients who failed SBT showed (before SBT),: significantly longer MV duration, the significant decrease in PaO2, SaO2 and PaO2/FiO2, and the significant increase in RSBI, significant decrease in IWI and significant decrease in Cst. Patients who failed SBT showed (After SBT); Significant increase in MAP, pulse, and RR, Significant increase in NT-pro BNP levels, significant increase CO, no difference incidence of systolic dysfunction .significant shortage in DT, significant lowering E’ velocity, significant increase E/E’ and diastolic dysfunction incidence, significant increase incidence of moderate and severe MR, significant increase PCOP and a significant decrease in follow up TAPSE and RVFAC.
Conclusion: Clinical, laboratory, echocardiography weaning parameters could be considered a sensitive and specific marker for prediction of weaning failure.

Keywords

Noninvasive; Weaning; Mechanical; Ventilation and Breathing

Introduction

Mechanical ventilation weaning covers the entire process of releasing a patient from the ventilator and the endotracheal tube. Weaning failure is usually defined as an ineffective spontaneous respiratory test (SBT) or ventilator support (including non-invasive ventilation) within 48 hrs. of extubation [1].
During spontaneous breathing, the transition from positive inspiratory pressure during mechanical ventilation to negative airway pressure challenges the physiological reserve of patients. When there is an imbalance between the ventilating needs and capacity of the patients, weaning fails [2].
There are various weaning indexes, all intending to decide the prognosis for this phase, which, contrary to what many believe, cannot be decided by clinical impression and spontaneous breathing test (SBT) alone [3].
Mechanical ventilation (MV) weaning is not an optimal indicator [4]. The cardiac performance was recognized as a common weaning failure etiology [5]. The occurrence of diastolic dysfunction was independently correlated with weaning failure, so an echocardiography assessment of LV diastolic function before weaning could be useful in identifying patients at risk of weaning failure [6].

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