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