Hypotension Prediction Index in Major Gastrointestinal Surgery
Condition: the Effect of Hypotension Prediction Index Application
MeSH terms: Hypotension
Study type: Interventional

Summary: 
      Intraoperative hypotension (IOH) is defined as a mean arterial pressure (MAP) of < 65mmHg
      during surgery. Patients undergoing major gastrointestinal (GI) surgery, such as
      esophagectomy with reconstruction, are at a high-risk of IOH because such surgeries typically
      require more than 3h to complete and require blood transfusion or inotrope administration.
      Critically, these surgeries involve organ removal or substitute connection, which require
      wound or flap anastomosis. IOH is believed to be associated with postoperative anastomosis
      necrosis. It increases the risk of postoperative intrathoracic or abdominal infection,
      resulting in septic shock, postoperative major organ dysfunction and mortality.

      The data of TWA-MAP< 65mmHg in the HPI guidance group will be significantly lower than that
      in the group without HPI guidance.
    

Detailed description: 
      Intraoperative hypotension (IOH) is defined as a mean arterial pressure (MAP) of < 65mmHg
      during surgery. Patients undergoing major gastrointestinal (GI) surgery, such as
      esophagectomy with reconstruction, are at a high-risk of IOH because such surgeries typically
      require more than 3h to complete and require blood transfusion or inotrope administration.
      Critically, these surgeries involve organ removal or substitute connection, which require
      wound or flap anastomosis. IOH is believed to be associated with postoperative anastomosis
      necrosis. It increases the risk of postoperative intrathoracic or abdominal infection,
      resulting in septic shock, postoperative major organ dysfunction and mortality.

      The Hypotension Prediction Index (HPI) is an algorithm made commercially available in 2019.
      On the basis of arterial waveform features, HPI predicts hypotension defined as MAP < 65 mmHg
      for at least 1 min. In two previous randomized trials(RCTs), the primary outcome was the
      severity and duration of hypotension, defined as a time-weighted average mean arterial
      pressure (TWA-MAP) less than 65 mmHg (formula: (total area under
      MAP<65mmHg(mmHg*hours))/(surgery length (hours));normal range:0.01-0.5mmHg).A higher data of
      TWA-MAP<65mmHg indicates severe and longer IOH. However, according to the results of the
      previous two RCTs, the effects of HPI guidance during surgery remain inconclusive.

      We aim to investigate whether HPI guidance can be used to reduce the duration and severity of
      hypotension during major GI surgery. Our hypothesis is that the data of TWA-MAP< 65mmHg in
      the HPI guidance group will be significantly lower than that in the group without HPI
      guidance. Postoperative major complications and mortality will be followed.

      Methods: Sixty patients aged 20 to 80 years undergoing elective GI surgery will be randomized
      to receive hemodynamic management with or without HPI guidance. Clinicians caring for
      patients assigned to the HPI guidance group will be alerted when the index exceeded 85 (range
      0 to 100) indicating the later occurrence of MAP< 65mmHg for at least minutes and a treatment
      protocol based on advanced hemodynamic parameters recommended vasopressor or inotrope, fluid
      administration, or observation. Primary outcome is the data of TWA-MAP<65mmHg. Postoperative
      complications will be recorded on postoperative day 3,7 and 30. The mortality rate from the
      time of hospitalization to postoperative 30 days will be recorded.

      The data of TWA-MAP< 65mmHg in the HPI guidance group will be significantly lower than that
      in the group without HPI guidance.
    

Intervention name(s): hypotension prediction index guided; without hypotesion prediction index guided
Intervention type(s): Device; Device
Intervention description(s): patients receiving hypotension prediction index monitoring and let the anesthesiologist' alerted the coming intraoperatiobe hypotension; patients receiving usual care without hypotension prediction index monitoring but with usual arterial line care
Allocation: Randomized
Intervention model: Single Group Assignment
Intervention model description: using hypotension prediction index guided in the operation
Masking: Triple (Participant, Care Provider, Outcomes Assessor)
Primary purpose: Other