Comparison between Remifentanil and Fentanyl for Analgesia- based sedation in mechanically ventilated patients in Intensive care unit .

INTERVENTION: Intervention1: Nil: Nil Intervention2: Remifentanil: Sedation based analgesia in mechanically ventilated patients in ICU . Dose : Bolus : 0.5‐1 mcg/kg Followed by Infusion at 0.1‐0.4mcg/kg/min Route: Intravenous Duration : Bolus : Over 30‐60seconds Infusion as long as mechanical ventilation required . Frequency : Duration of mechanical Ventilation Control Intervention1: Sedation based Analgesia .: Sedation based Analgesia given in mechanically ventilated patients in ICU . Control Intervention2: Fentanyl: Sedation based analgesia in mechanically ventilated patients in ICU . Dose: Bolus : 1‐2 mcg/Kg Followed by Infusion at 0.02‐0.2mcg/kg/min Route: Intravenous Duration : As long as mechanical ventilation required . Frequency: Duration of mechanical Ventilation CONDITION: Health Condition 1: J22‐ Unspecified acute lower respiratory infection PRIMARY OUTCOME: To compare the effectiveness of remifentanil and Fentanyl in achieving target analgesia in mechanically ventilated patients in ICU .Timepoint: 12,24,36 and 48 hours after initiation of study drug . SECONDARY OUTCOME: To compare the time to extubation ,incidence of adverse effects , clinical outcomes between remifentanil & fentanyl.Timepoint: From initiation of study drug until extubation . Adverse effects assessed during treatment & up to 24 hours post discontinuation. Clinical outcomes & cost effectiveness assessed until ICU discharge . INCLUSION CRITERIA: 1.Ventilation for more than 48 hours at the time of enrolment . 2.Age 18 years or older . 3.Written Informed Consent .