Preoperative Ultrasound Guided Evaluation of SVC-CI and IVC -CI as Predictors of Hypotension After Induction of Anaesthesia in Major Onco-surgery
Condition: Total Fluid Volume Decreased
MeSH terms: Hypotension
Study type: Observational

Summary: 
      Patients undergoing major Oncosurgeries are fluid deficit due to preoperative fasting ,
      inadequate intake due to disease hence prone to development of hypotension after induction of
      general anaesthesia owing to vasodilatory effects of anesthetic induction agents.
      Investigators plan study to measure ultrasound guided Superior Vena Cava and Inferior Vena
      Cava collapsibility Index as predictors of hypotension after induction of General
      anaesthesia.
    

Detailed description: 
      Investigators plan prospective study , written informed will be taken from all included
      patients. In the OR 5 lead ECG, NIBP,SPO2 monitors will be attached , patients will be
      explained about Ultrasound imaging . Preinduction using SONOSITE EDGE II ultrasonography
      machine and placing high frequency linear array probe (6-13 Hz) beneath the middle of the
      clavicle aligned in deltopectoral groove to obtain short axis view of
      Subclavian/Infraclavicular axillary vein in B-Mode (2-D imaging). Doppler pulse waveform and
      minimum and maximum diameter measurements of SVC will be obtained in M-mode , both during
      spontaneous breathing and after deep inspiration, using digital calipers after freezing the
      image. The collapsibility index CI will be calculated using the following equation SCV AV CI
      = (dSCV max- dSCV min)/ dSCV max ×100.

      A phased array or cardiac ultrasound probe (1-5Hz) will be placed in the subxiphoid window to
      view IVC at the junction of IVC with right atrium .Then the transducer will be adjusted to
      obtain the long axis view of IVC. Doppler pulse waveform will be obtained to ensure imaging
      of IVC and then in the M mode the minimum and maximum diameter measurements of IVC will be
      obtained both during spontaneous breathing and after deep inspiration, using digital calipers
      after freezing the image. The collapsibility index CI will calculated using the following
      equation:IVC CI = (dIVCmax- dIVCmin )/ dIVCmax ×100 . In all the patients both SVC and IVC
      -CI will be calculated.

      All patients will receive standard General Anesthesia with IV Fentanyl 1-2 mcg/kg , Sleeping
      dose propofol , Atracurium 0.5mg/kg and orally placed Endotracheal tube.The heart rate (HR)
      and mean arterial pressure (MAP) will be recorded in two phases .Intraoperative hypotension
      (IOH) been defined as MAP<60mmHg or >30%decrease in MAP from baseline.

        1. Post induction phase: Readings will be taken at 1 min intervals from the start of
           induction till intubation (upto 5 minutes) and

        2. Post intubation phase: Readings will be taken at 2 min intervals upto 10 min and at 5
           min intervals up to 30 mins or till incision . Each hypotensive episode encountered will
           be treated with leg lifting first (lifting both lower extremities for 2 minutes by
           technical staff) , if hypotension persists then IV Ephedrine 6 mg boluses will be given
           . All patients will receive preloading 200ml crystalloids prior to induction of
           anesthesia .
    

Intervention name(s): Ultrasound guided Superior Vena Cava Collapsibility Index; Inferior Vena Cava Collapsibility Index
Intervention type(s): Other; Other
Intervention description(s): Preoperative Ultrasound guided Superior Vena Cava Collapsibility Index will be measured; Preoperative Inferior Vena Cava Collapsibility Index will be measured.
Observational model: Other
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Adult patients undergoing major Onco-surgeries.