Comparing the Hemodynamic Effects of Volume Loading vs Non-loading During Induction of Anesthesia in Fluid Responder Patients With Coronary Artery Disease Undergoing Elective Coronary Artery Bypass Graft Surgery: a Randomized Controlled Study.
Condition: Post Induction Hypotension
MeSH terms: Coronary Artery Disease; Myocardial Ischemia; Coronary Disease; Hypotension
Study type: Interventional

Summary: 
      All preoperative cardiac medications will be continued till the morning of the surgery,
      except angiotensin converting enzyme inhibitors. Patients will be pre-medicated with
      intramuscular morphine at 0.1 mg.kg-1 one hour before surgery. Upon arrival to the operating
      room, Initial monitoring included five lead electrocardiograms, non-invasive blood pressure,
      and pulse oximetry. At the attending anesthetists discretion, intravenous midazolam (0.05
      mg/kg) will be administered for anxiolysis. Under local anesthesia an arterial line will be
      placed in the right radial artery and central venous line will be placed in the right
      internal jugular vein.

      Before induction of anesthesia for all study patients, Electrical cardiometry device (ICON;
      Cardiotonic, Osypka; Berlin, Germany) will be applied to the patient through 4 electrodes at
      the following sites: Below the left ear, Above the midpoint of the left clavicle, Left
      mid-axillary line at level of the xiphoid process and 5 cm inferior to the third electrode.
      Stroke volume variability (SVV) was measured while patient maintaining standard calm
      breathing at 8 breath/minute for one-minute. Patients with SVV less than 13% will be excluded
      from the study. Thus, all patients included will be considered fluid responders[5]. The
      baseline data in the form of heart rate, systolic, diastolic, and mean systemic arterial
      pressures, CO, CI, SV, SVI, SVV, SVR, and SVRI will be recorded during the study period in
      all the patients.

      Patients will then be randomly divided into two groups; control group will receive nothing
      before induction, while patients in volume loading group will receive volume loading of
      8ml/kg Ringer acetate over 10 minutes. The volume loading will be repeated until SVV would be
      below 13%. The volume loading would be given by an anesthesia resident not involved in data
      collection.

      For induction, Patients in both groups will receive 3 mcg/kg of fentanyl. Then in all
      patients, propofol will be injected slowly at 1.5 mg/kg in 0.25 mg/kg increments every 20 s
      till clinical loss of consciousness. Clinical loss of consciousness (defined as no response
      to auditory command) will be assessed by asking the patients repeatedly every 20 s to open
      their eyes. After loss of consciousness, atracurium 0.5 mg/kg will be administered to
      facilitate tracheal intubation. The stress response to laryngoscopy and tracheal intubation
      is secondary to marked increase in sympathetic activity and manifested in general as
      tachycardia and hypertension and will be managed with increments 0..25mcg fentanyl.
      Hemodynamic changes; 20 beats/ minute or 20 mmHg difference in heart rate and blood pressure
      respectively were considered to be significant. Anesthesia will be maintained by isoflurane
      (1-1.2 %). Patients will be mechanically ventilated to have target of PO2 above 300mmhg and
      PCO2 between 35-40mmg.

      Any episode of hypotension (defined as mean arterial pressure [MAP] < 80% of the baseline
      reading and/or MAP <60 mmHg) will be managed by 5 mcg norepinephrine (which could be repeated
      if hypotension persists for 2 minutes).

      If bradycardia occurred (defined as heart rate less than 50 bpm), it will be managed by IV
      atropine bolus (0.5 mg).

      Hemodynamic data will be recorded 1-minte before the induction, 1-and 2-minutes after loss of
      consciousness, 1-minutes after intubation, then every 2-minutes for 15-minutes after
      intubation., the end point of the present study. Throughout this period the lungs will be
      mechanically ventilated with 50% air-oxygen mixture, to maintain an end-tidal carbon dioxide
      between 35 and 40 mmHg.
    


Intervention name(s): Ringer acetate
Intervention type(s): Drug
Intervention description(s): 8ml/kg Ringer acetate over 10 minutes
Allocation: Randomized
Intervention model: Single Group Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention