ScvO2-Centered Optimisation of RED Blood Cell Transfusions

ScvO2-Centered Optimisation of RED Blood Cell Transfusions (SCORED) - Protocol for a Multicenter, Randomised, Controlled Clinical Trial to Compare the Central Venous Saturation (ScvO2) Guided Transfusion Trigger Versus Transfusion Based on Clinician's Decision in the Critically Ill

This clinical trial aims to personalise red blood cell transfusion strategies in the crtitically ill patients. The amount of transfusions needs to be minimised in order to prevent adverse events and organ dysfunctions linked to high amounts of red blood cell transfusions.

The researchers aim to investigate the efficacy and safety of measuring the central venous oxygen saturation (ScvO2) (oxygen content in a venous blood sample taken from a central line) to guide clinicians if transfusion is necessary.

The researchers aim to compare the ScvO2 guided transfusion strategy with transfusion based on the clinician's judgment (taking into consideration the patients' comorbidities and actual vital parameters).

Red blood cell transfusions are routine practice in the management of critically ill patients; 25% of patients treated in the intensive care unit receive a transfusion. Its aim is to restore adequate oxygen delivery to peripheral tissues. Transfusion has numerous potentially harmful effects and significantly increases healthcare costs. International guidelines recommend a restrictive transfusion policy. These recommendations are based on studies that use the hemoglobin level as a transfusion trigger. Hemoglobin level does not provide sufficient information about the balance between oxygen delivery and oxygen consumption, which determines tissue oxygenation. Incorporating a physiological parameter into the transfusion decision-making algorithm may ensure a personalized transfusion strategy. Clear evidence is lacking regarding the usefulness of physiological transfusion triggers in the treatment of anemia in critically ill patients. Case reports and retrospective studies have been published, but no randomized trials have been conducted. Central venous oxygen saturation (ScvO₂) reflects the balance between oxygen delivery and consumption; its normal physiological range is 70-75%, and a decrease indicates inadequate oxygen delivery and oxygen supply/demand imbalance. Thus, it may serve as a potential physiological trigger for clinicians in personalized transfusion management of hemodynamically stable intensive care patients.

Therefore our aim is to examine the efficacy and safety of an ScvO₂-guided transfusion trigger compared with clinician decision-based transfusion in critically ill patients.

Inclusion Criteria:

• Patient in medical/surgical/trauma ICU

• Hemoglobin level between 7g/dl and 9g/dl

• Written informed consent by patient or next of kin

• Hemodynamically stable:

  • CRT normal
  • Serum lactate <2 mmol/l
  • MAP >65 mmHg
  • noradrenalin < 0,2 mcg/kg/min and no increase in 6 hours
  • No new ischemic change on ECG

• Monitored with CVC, arterial catheter, hourly urine output

• Respiratorily stable

  • No support or
  • Nasal canula/face mask O2 supplementation or
  • NIV or
  • Invasive mechanical ventillation: PC/VC/PS, PEEP< 15 cmH2O FiO2 < 50% and no increase in 6 hours

• PiCCO or expert ECHO available within 48hours

Exclusion Criteria:

• ScvO2>80%
• Acid-base imbalance (pH<7.3 or pH>7.5)
• Chronic kidney disease (KDIGO Stage 3-4-5)
• Acute heart failure (ESC 2021 definition)
• Pregnancy
• Active bleeding
• Neurotrauma requiring intracranial pressure monitoring
• Morbid obesity BMI >40
• Horowitz Quotient (paO2/FiO2) < 200
• Acute and chronic liver failure (Child-Pugh B,C)
• Fever