Evaluation of incidence of sevoflurane induced emergence delirium following general anaesthesia in adults- An observational study

Delirium is a disturbance of consciousness with inattention accompanied by change in cognition or perceptual disturbance that develops over a short period and fluctuates over time. Delirium during postoperative period can be divided into Emergence delirium and Postoperative delirium based on its onset. Emergence delirium or Emergence agitation or Postanesthetic excitement occurs during immediate postoperative period and lasting for 5-15mins. Emergence delirium is a clinical condition in which patients are awake but experience alterations in disorientation and other mental status changes that ranges from confusion and lethargy to violent and harmful behaviour. Emergence delirium during immediate post anesthesia period is common. It may lead to serious consequences for the patients such as injury, increased pain, hemorrhage, self Extubation, removal of catheters, and it can necessitate physically or chemically restraining the patients. Sevoflurane is an inhalational anesthetic used widely as outpatient anesthesia due to its excellent hemodynamic stability and low blood solubility, which allows rapid induction and emergence from general anesthesia, as well as control of depth of anesthesia. How ever sevoflurane is associated with higher incidence of emergence agitation in children. The rapid removal of residual anesthetics due to low blood solubility of sevoflurane has been suggested to cause emergence delirium in some patients.

To determine incidence and risk factors of emergence delirium in adults following general anesthesia. Primary objective- Incidence of emergence delirium with sevoflurane in adults. Secondary objective - To identify factors associated with emergence delirium in perioperative period.

A prospective observational study to be conducted over 1 year where procedures in specialities including general surgeries, Ent, Gynecological surgeries are performed. Informed consent will be obtained preoperatively. Detailed history and physical examination , baseline data like heart rate, blood pressure and basic investigations will be collected. An iv access with 18Giv cannula will be secured for all the patients. Premedication such as tab. Ranitidine 150mg and tab. Alprazolam 0.5mg given night before surgery and 6am on day of surgery. After shifting the patient inside OT, proper standard monitoring of spo2, NIBP, ECG, Etco2 will be established and baseline variable values will be noted before the procedure. Patient will be premedicated with inj. midazolam 0.02mg/kg iv , inj. Glycopyrolate 0.01mg/kg iv, inj. fentanyl 2mcg/kg iv then an inducing agent inj. propofol 2mg/kg iv followed by muscle relaxant inj. vecuronium 0.08mg /kg iv along with inhalational agent sevoflurane. Patient lung were ventilated using 100% oxygen to maintain etco2 from 35 to 45mmhg. Tracheal intubation will then be performed approximately 3mins after anesthesia induction by trained an anesthetist. Tracheal intubation will be done with direct laryngoscope using macintosh blade with appropriate size ET tube. ET tube will be secured at angle of mouth and et tube position confirmed with 5point auscultation method. Then pt connected to mechanical ventilator. After tracheal intubation urinary catheters were inserted in all the patients. Plane of anesthesia is maintained throughout with inhalational agent sevoflurane at 1-2%. In all patient muscle relaxation was maintained with inj. vecuronium 0.1mg/kg iv. At the conclusion of procedure, the inhaled agents were discontinued and the fresh gas flow was maintained with 6L of oxygen. Patient given adequate analgesics. By the end of procedure Extubation done with reversal agent inj. Myopyrolate iv according to patient requirement. ET tube was removed when tidal volume >5ml/kg , respiratory rate >12 cpm, the swallowing and cough reflex were active and spo2 maintained at >95% for five minutes on room air. Pain was assessed after tracheal extubation and reassessed after ten minutes on numerical rating scale. we used the Rikers sedation agitation scale which was developed to assess the level of agitation and sedation from the time of turning off sevoflurane, during extubation and immediate post anesthesia period (5-15mins). We divided the patient in to two categories using Riker sedation scale: Non agitated patients (levels 1- 4) and agitated patients (level: 5-7). We then subdivided those patients in agitated group as agitated, very agitated, and dangerously agitated. Agitation was correlated with following factors: 1. age 2. gender 3. duration of surgery 4. comorbidities 5. alcoholism 6. postop pain. Emergence delirium is often treated with combination of Non pharmacological and pharmacological interventions. Non pharmacological strategies include reassuring the patient, managing pain with analgesics. Pharmacological options which include administering intravenous bolus of sedative agents like midazolam (0.03-0.1mg/kg iv) or propofol (0.5- 1mg/kg iv) or opioids like fentanyl (0.5-1mcg/kg iv) are used. Other drugs used in treating emergence delirium are ketamine ( 0.25mg/kg iv), Dexmedetomidine (0.3- 1 mcg/kg iv), clonidine (2-3mcg/kg iv).

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