Hemodynamic Optimization Through Pleth Variability Index for OHCA

Less than half of the patients suffering from sudden cardiac arrest arrive at the hospital alive. Of these survivors less than half will be discharged alive from the hospital without being severely disabled.

The most frequent cause of death during the first 24 hours since admission to the hospital is related to cardiovascular instability and failure. In the early phases of ROSC from out of hospital cardiac arrest patients are hemodynamically unstable and management relies on few non invasive measurements such as non invasive blood pressure, SatO2, EtCO2 and continuous ECG.

Even at arrival at the ER patients are monitored by non-invasive parameters during the early phases and invasive hemodynamic monitoring may be delayed until ICU admission. Recent technological advances allow continuous non invasive evaluation of response to fluid challenge in mechanically ventilated patients through the pleth variability index.

The research proposal by the investigator is a randomized prospective interventional, single-center study based at Saint Pierre University Hospital, carried out in the emergency department.

Participant will be OHCA admitted alive to the Emergency department with unstable hemodynamics defined as a mean systolic pressure below 70 mmHg or a blood lactate concentration of at least 36 mg/dL (4 mmol/L).

The criteria for exclusion from the study will be pregnancy, being a prisoner or having limitations of therapeutic effort.

During the study the investigators will evaluate whether an hemodynamic protocol based on pleth variability index on top of routine non invasive monitoring is superior to the routine non invasive monitoring only ( such as non invasive blood pressure, EtCO2, SatO2 and ECG) in terms of lactate clearance and fluid balance.

In both study arms the treating clinician will be encouraged to achieve and maintain the following hemodynamics goals: a mean arterial pressure above 70mmHg, a diuresis above 0.5 ml/kg/h, a capillary refill time below 3 and a clearance of lactate above 10% after 2 hours.

In the control arm the participants will be initially resuscitated with an initial bolus of NaCl 0.9% 10ml/kg whenever the patient is not meeting the set hemodynamic goals. If deemed necessary a second fluid challenge of 100 ml of Albumin 20% will be administered to the patient. Any further fluid challenge will be done with NaCl 0.9% 10ml/kg. At any moment the treating clinician will be allowed to initiate a continuous infusion of noradrenaline or dobutamine to achieve the hemodynamic goals. If deemed necessary clinicians will be allowed to perform a cardiac echography at any moment to assess the hemodynamic needs of the patient. Patients will be continuously reassessed to verify that the hemodynamic goals are achieved.

In the intervention arm patient will be resuscitated according to their PVI. Whenever the PVI will be above 13% the patient will be considered as being fluid responsive and a fluid challenge will be performed whenever the patient is not meeting the set hemodynamic goals. First fluid challenge will be an initial bolus of NaCl 0.9% 10ml/kg. If deemed necessary a second fluid challenge of 100 ml of Albumin 20% will be administered to the patient. Any further fluid challenge will be done with NaCl 0.9% 10ml/kg. If the hemodynamic goals are not achieved and the PVI is below 13% an infusion of noradrenaline will be initiated aiming at a mean arterial pressure of at least 70 mmHg. Infusion of dobutamine to achieve the hemodynamic goals will be started according to clinician decision. If deemed necessary clinicians will be allowed to perform a cardiac echography at any moment to assess the hemodynamic needs of the patient.

Patients will be continuously reassessed to verify that the hemodynamic goals are achieved.

In both arms participants will be sedated according to our hospital protocol for OHCA which includes propofol and remifentanyl titrated to achieve a good synchronization between the patient and the ventilator. If despite sedation a good synchronization between the patient and the ventilator cannot be achieved participants will be initially curarized.

Intervention will end at ICU admission when hemodynamic therapeutic decisions will be based on invasive hemodynamic monitoring.

Trainings will be organized for nurses and postgraduate doctors during the months preceding the study to familiarize the medical-nursing team with the study.

Inclusion criteria

• Out of Hospital Cardiac Arrest
• ROSC before Emergency department admission
• Mecanically ventilated with a tidal volume of at least 6 ml/IBW
• Admitted to the emergency department with a lactate > 4mmol/L or a mean arterial pressure below 65 mmHg or a TRC>5 seconds

Exclusion criteria

• Minor
• Prisoners
• Pregnant woman
• Atrial fibrillation