Clinical prediction scores predicting weaning failure from invasive mechanical ventilation: Role and limitations

Table 5 Summary of various scores for predicting weaning failure in patients receiving invasive mechanical ventilation

Score	Components	Value	Advantages	Disadvantages
A: RSBI	Respiratory rate; Vt; RSBI = RR/Vt	< 105 – weaning success; > 105 – weaning failure	Simple; easy to calculate	Affected by multiple factors – fever, infection, anxiety, restrictive disorders, weaning technique and suctioning; not the best predictor for COPD/neuro-medical and neurosurgical pt.
B: CROP index	Compliance (thoracic); respiratory rate; oxygenation (Arterial); pressure (P1 Max)	> 13 mL/breath/min – successful weaning	Incorporates respiratory and ventilatory parameters	Complex calculations; not tested in neuro-medical/neurosurgical pt.
C: ExPres score	RSBI; dynamic lung compliance; days of IMV; GCS; muscle strength; haematocrit; creatinine; neurological comorbidity	Score; > 59 – extubate pt.; 45-58 with no risk factors – extubate pt.; 45-58 with risk factors – extubate to NIV; < 44 – extubation failure	More robust score; simple tool; shown to reduce extubation failure rates	Needs large scale studies for validation
D: HACOR	Heart rate; acidosis; consciousness; oxygenation; respiratory rate	Score > 5 – weaning failure	Simple bedside tool	Limited studies; large scale trials required to assess for validity
E: WEANS NOW	Weaning parameters; endotracheal tube; ABG; nutrition; secretions; neuromuscular blocking agents; obstructive airway disease; wakefulness	Score of 1 or more – weaning failure	Incorporates multiple parameters	Very complex score; widespread application may be difficult
F: BWAP	Pulmonary; physiological; psychological	Score > 50 – weaning success	Comprehensive weaning checklist	Limited literature; modified-BWAP may be more practical
G: Morganroth scale	Adverse factor score; ventilator score	Score < 55 – successful weaning; range – 27 variables max score 75	Can be applied to pt. requiring short-term and long-term IMV	Small study; multiple variables considered
H: Persian weaning tool	Respiratory; cardiovascular; general status of pt.	26 parameters; range 26-75; score > 50 –readiness to wean	Comparable to BWAP score	Limited literature regarding its utility
I: Gluck & Corgian score	RSBI; ratio of dead space/Vt; static lung compliance; airway resistance; CO2 pressure	Score < 3 – weaning success; score of 3 – not equivocal; > 3 failure to wean	Simple tool; easy bedside measurement	Small study; large trials warranted

BWAP: Burns wean assessment program; CO₂: Carbon dioxide; COPD: Chronic obstructive pulmonary disease; GCS: Glasgow coma scale; IMV: Invasive mechanical ventilation; NIV: Non-invasive ventilation; pt.: Patient; RR: Respiratory rate; RSBI: Rapid shallow breathing index; Vt: Tidal volume; ABG: Arterial blood gas.