Clinical Profile of Patients Requiring Prolonged Mechanical Ventilation and their Outcome in a Tertiary Care Medical ICU.

Intoduction: An increasing number of patients require mechanical ventilation and there has been a proportional increase in patients needing prolonged mechanical ventilation (ventilated for ≥ 21 days, for atleast 6 hours per day). It accounts for about 10% of all mechanically ventilated patients. Although these patients represent a smaller proportion of intensive care unit (ICU) patients, they consume substantial ICU resources. We studied etiology, metabolic and clinical profile, complications and outcome of these patients.

Methods: This was a prospective observational study in the medical ICUs of a tertiary hospital over 18 months. All patients above 12 years of age requiring prolonged invasive mechanical ventilation were recruited. Detailed clinical and laboratory records were noted. Sequential Organ Failure Assessment (SOFA) score was calculated on admission.

Results: Of a total 1150 patients who were admitted in ICU during study duration, 34.5% (n= 397) needed mechanical ventilation and 3.91% (n=45) required prolonged mechanical ventilation. Most common patient subsets were: acute inflammatory demyelinating polyneuropathy (AIDP) 28.50% (n=13), cerebro-vascular accident (CVA): 17.30% (n=8), tetanus 8.60% (n=4) and acute respiratory distress syndrome (ARDS) 6.50% (n=3). The mean age of patients was 32 years. Electrolyte imbalances observed were hypocalcaemia (84.44%), hypomagnesaemia (40.9%), hypokalemia (31.11%) and hypophosphatemia (23.8%). Ventilator-associated pneumonia (VAP) (53.33%) was the most frequent complication, followed by decubitus ulcers (40%) and deep vein thrombosis (8.89%). Mean duration of ICU stay was 57.02 days ± 44.73 days. Twenty six out of 45 patients (57.75%) were successfully weaned off ventilator support and discharged from the hospital. The SOFA score of patients who survived (mean 2.15) was lesser than that of patients who expired (mean 2.89) (p= 0.36, ns).

Conclusions: The incidence of prolonged mechanical ventilation in our study was 3.91% of total 1150 ICU admissions and 11.3% of the 397 patients requiring invasive mechanical ventilation. AIDP, CVA, tetanus and ARDS were the most common diagnoses. Survival in the study population was 57.75%. VAP was the most common complication. High incidence of hypocalcaemia, hypomagnesaemia, hypokalemia and hypophosphatemia was noted in patients requiring prolonged mechanical ventilation.