Effect of High volumeHemodiafiltration on Lung Oxygenation

Effect of High Volume Hemodiafiltration on Lung Oxygenation, Lung Mechanics and Biomarkers in Mechanically Ventilated Patients With Severe Sepsis

High volume hemodiafiltration (HVHDF) has been used in septic patients to get hemodynamic improvement and possibly survival benefit.

Sepsis, defined as life-threatening organ dysfunction caused by dysregulated immune response to infection. Hemofiltration has been suggested as beneficial in restoring immune homeostasis. High volume hemodiafiltration (HVHDF) is a hybrid method of intermittent renal replacement therapy (RRT), where high filtration volumes are applied. In several studies; higher filtration volumes have been shown to achieve hemodynamic improvement and possibly survival benefit in patients with septic shock.

Inclusion Criteria:

1. ≥ 18 years

2. Severe sepsis defined by Quick SOFA score by presentation of 2 or more of the following criteria:

   • Mental clouding: decreased glasco coma scale GCS < 15
   • Hypotension: Systolic blood pressure < 100 mmgH
   • Tachypnea: respiratory rate > 22 breath/ minute Then serum lactate is analysed to confirm sepsis hypoperfusion if ≥ 2mmol/L

3. Organs dysfunction (including one of them respiratory failure).

Organ dysfunctions are defined as following:

Respiratory dysfunction (criteria for ARDS):

• PaO2/FiO2 <200
• Bilateral infiltrates in chest X-ray
• Resistant hypoxemia
• Tachypnoea (RR > 40 breath/minute)
• The need for invasive mechanical ventilation
• Excluded cardiac causes of pulmonary edema

CNS failure:

• Decreased GCS ≥ 4 decreased points

CVS dysfunction:

• Sustained hypotension even on very high inotropes doses (Noradrenaline >1µm/min)+ adrenaline>1.5µm/min associated
• with high CVP pressure > 12 mmHg and not responding to fluid challenge test to exclude hypovolemia.
• Cardiomegaly detected by either echocardiography assessment, or chest X-ray
• Resistant frequent ventricular ectopics not explained by organic causes.

Liver dysfunction:

• Elevated total and direct bilirubin than double normal or basal levels
• Elevated prothrombin time > 17 seconds or INR > 1.5
• Elevated liver enzymes > triple normal level

Renal dysfunction:

• Decreased urine output < 0.5 ml/kg.
• Elevated creatinine level > 164 µmol/L (1.5mg/dL).
• Decreased creatinine clearance <50ml/minute if available.

Bone marrow depression:

• Decreased platelets < 90 X 103/µL
• Decreased leukocytes <4 X 103/µL
• Decreased RBCs count < 4 X 106/µL

Exclusion Criteria:

1. Patient relatives' refusal
2. Pregnancy
3. Recent active internal hemorrhage
4. Not mechanically ventilated.
5. Hypersensitivity to the dialyser fluid