Hemodiafiltration: A Novel Approach for Treating Severe Amitriptyline Intoxication
A 24 years old previously healthy male patient was brought to emergency service in coma (GCS:3). He was found unconscious at home by his friend and there was a suicide note near him. He had taken 40 tablets of amitriptyline 25 mg (16 mg/kg) about 8 hours before admission. After admission to intensive care unit, heart rate, invasive blood pressure, central venous pressure were monitored. A total urine output was obtained during 24 hours.\nOn physical examination the patient was unconscious and there was no response to painful stimulus. The pupils were isochoric and light reflex was bilaterally positive. There were generalized tonic-clonic seizures but no neurological localizing signs were noted. His blood pressure was 110/60 mmHg, heart rate 130/min, respiration rate 28/min, and temperature 36.3°C. Arterial blood gas (ABG) values were pH: 7.39, pCO2: 45 mmHg, pO2: 77.5 mmHg, HCO2: 27.6 mmol/L and base excess (BE): 2.7 mmol/L. Laboratory findings of the patient were: Hemoglobin 16.3 g/dL; hematocrit, 27.6%; white blood cell count, 11.300/mm3; and platelet count, 223,000/ mm3. Serum electrolytes were sodium: 142 mmol/L, potassium: 4.5 mmol/L, urea: 0.72 mg/dL., creatinine: 0.69 mmol/L, Aspartate transaminase (AST): 33 IU/L, Alanine transaminase (ALT): 22 IU/L. Plasma drug concentration was 0.9 μg/ml. Electrocardiography (ECG) showed ventricular tachycardia with wide QRS complexes [] and QT (0.50 ms) prolongation. Chest X-ray showed a pneumonic infiltrate, possibly due to aspiration of gastric content.\nGeneralized tonic-clonic seizures were stopped with midazolam. Activated charcoal (1 g/kg per dose) was administered via nasogastric tube, sodium bicarbonate (2 mEq/kg) infusion was started for alkalinization. Initially nasal oxygen with a 5 L/dk was given but 2 hours after admission to ICU because of the decrease in pO2 levels evaluated with ABG as pH: 7.35, pCO2: 49 mmHg, pO2: 75 mmHg, HCO2: 28 mmol/L and base excess (BE): 3 mmol/L the patient was intubated and mechanical ventilation support was started in SIMV mode. Yet there was no response to conventional therapies, GCS was 3 and urine output was very low (10 ml/hr). Although the level of creatinine was 0.69 mmol/L HD was performed to the patient in deep coma. It was the 15th hour of ingestion HD started and applied for 20 hours with 27 lt potassium free solution and 12000 U heparin. Flow rate was arranged between 50 and 100 ml/min according to hemodynamic condition of the patient and coagulation parameters were followed and there was no complication. Neurologic and cardiovascular status returned to normal after HD. GCS was 15 and QRS complexes were also normal []. The patient extubated on the second day of admission. On the 3rd day laboratory findings and vital signs were stable. After psychiatric consultation he was discharged from hospital on the 4th day.