Vol 5 | Issue 1 | Jan-April 2019 | page: 18-20 | Anupam Raj, Vijay Shankar, Meera Kharbhanda, Neerav Goyal
Authors: Anupam Raj [1], Vijay Shankar [1], Meera Kharbhanda [1], Neerav Goyal [2].
[1] Department of Anaesthesia, Indraprastha Apollo Hospital New Delhi
[2] Dept Of Liver Transplantation , I ndraprastha Apollo Hospital New Delhi
Address of Correspondence
Dr. Anupam Raj,
Department of Anaesthesia, Indraprastha Apollo Hospital New Delhi
Email: anupamraj21@gmail.com
Abstract
A 32-year-old female patient was admitted in our hospital with a diagnosis of Hepatitis E induced acute liver failure. She was immediately intubated and mechanically ventilated due to a high grade of hepatic encephalopathy. ONSD measured on admission was suggestive of raised ICP. She was initiated on CRRT along with other anti-edema measures. She underwent LDLT on the third day of admission. ONSD was monitored at regular intervals to identify cerebral edema and CRRT was continued intra operatively with the aim of preventing cerebral edema. We were able to extubate the patient within 18 hours of the surgery. The patient had a fastpost-operative recovery and we were able to discharge her on the 12th post-operative day.
Keywords: Acute Liver Failure, Cerebral Edema, Pregnancy, Hepatitis E, Liver Transplant, Continuous Renal Replacement Therapy
Introduction
Hepatitis E is the most common cause of hepatitis in developing countries. It can lead to acute liver failure especially in pregnant females, with the severity of infection and mortality rate increases with the gestational age. Cerebral edema leading to intracranial hypertension (ICH) is a major cause of mortality in patients with acute liver failure. Studies have found out that only < 25 % of cases of raised intracranial pressures could be diagnosed by clinical examination alone. Even though many guidelines recommend invasive intracranial pressure monitoring (ICP) for Acute Liver Failure (ALF), the use of these modalities have shown to cause hemorrhagic complications because of the coagulopathy associated with ALF. However, monitoring of ICP may be beneficial in identify in g ICH and guiding the administration of targeted therapy. The measurement of optic nerve sheath diameter (ONSD) is a non-invasive and reliable technique with proven efficacy in detecting elevations of ICH in neurosurgical patients. Most of the studies have recommended a cut off value of > 0.48 cm as an indicator of ICP > 20 mm Hg. ONSD measurement is noninvasive, rapid, easy & requires less expertise which could be crucial in early identification of intracranial hypertension during the preoperati ve a s wel l a s intraoperati ve management of a patient with ALF undergoing liver transplantation. Hyperammonemia is an important cause of brain edema in patients with acute liver failure. Ammonia levels of > 150-200µmol/l have been co-related to increased intracranial pressure and brainstem herniation. In addition to the conventional anti ammonia measures, renal replacement therapy (RRT), can also be used to lower blood ammonia levels. The Current standard is to use CRRT as a modality to reduce ammonia levels in ALF patients owing to its superior haemodynamic stability. We present a case of a lady who was admitted in our hospital with ALF. Diagnosis of raised intracranial pressure was established at the time of admission by measurement of ONSD and CRRT was initiated. Living Related Liver Transplantation was done on the 2nd day of admission and was discharged on the 12th postoperative day
Case Report
A 31-year-old female, 8 months and 2 weeks pregnant was admitted in a local hospital in v i ew of j aundi c e for a day. Initial investigations over there showed deranged LFTs with a viable foetus. She underwent LSCS under GA. However, following the LSCS her sensorium worsened along with 2 episodes of lower gastrointestinal bleed. She was referred to the liver transplant unit of our hospital for further management with a diagnosis of HEV induced Acute Liver failure. On admission to the transplant ICU, she was found to be on grade 3 hepatic encephalopathy, tachycardic, tachypnoeic, normotensive and normothermic. Pupils were reacting, however, the ONSD was found to be 0.49 cm in both the eyes. A decision was made to selectively intubate and ventilate the patient and initiate CRRT with the aim of lowering serum ammonia levels. The investigations on admission are given in table1. After intubation, venous & arterial access was obtained under ultrasound guidance for haemodynamic monitoring. A 11 fr dialysis catheter was secured in the right femoral vein under ultrasound guidance. CRRT was initiated immediately with ultrafiltrate at 0 ml per hour since urine output was more than 1 ml/kg/hour. Other antioedema measures like he a dupposition, moderate hyperventilation, mannitol, and hypertonic saline to maintain serum sodium between 150-155 mmol/l were initiated. Special care was taken to avoid hyperthermia and maintain the temperature at around 35 degrees. Pupillary reaction and ONSD were measured hourly and within 3 hours of initiation of CRRT, it was noted that the ONSD was < 0.47 mm in both the eyes. All the ONSD measurements were done by a single operator. She met the king’s college criteria for liver transplantation. An emergency meeting by a multi-disciplinary team was called for and it was decided to go ahead with emergency living related liver transplantation after the family counseling and donor work-up was done. Among the numerous perioperative concerns, one of paramount importance was the optimal monitoring and management of surges in intracranial pressure during the intraoperative period. A CT brain was performed prior to shifting the patient to the theatre which showed features of mild cerebral edema with no signs of herniation. Anaesthesia was induced using intravenous fentanyl and inhalation of sevoflurane through the already pre-existing endotrachealtube and was maintained by continuous infusion of propofol at 6mg/kg/hour and atracurium at 0.3 mg/kg/hour. Due to the anticipated fluid and electrolyte shifts during the operation which could exacerbate her cerebral edema it was decided to monitor her ONSD at 2nd intervals during the surgical procedure. CR RT was continued during the intraoperative phase also with the aim of preventing cerebral edema and acidosis. The ONSD in both the eyes remained within 0.47 mm throughout the procedure. The surgery lasted around 12 hours and was largely uneventful. In the ICU acidosis was corrected overnight, inotropic support weaned off, CRRT was discontinued since ONSD was within the normal range. She was extubated after 18 hours. Graft function improved satisfactorily, immunosuppression and antibiotics were continued as per protocol. She was shifted out of the ICU on post-operative day 5 and discharged by the 11thpostoperative day. Her postoperative investigations are given in table 2.
Discussion
Prevention, early identification, and treatment of cerebral edema are of paramount importance in improving outcomes in acute liver failure. Traditional monitors of ICP carry a high risk of bleeding and infection. Raised ICP is transmitted to the optic sheath through the subarachnoid space. The mechanism is like the development of papilledema. However, unlike papilledema, the optic nerve sheath distention occurs within a matter of seconds which makes ONSD a valuable tool to diagnose acute elevations in ICP [5,10,11]. The largest study co-relating ONSD readings with simultaneous ICP measurements were performed by Rajajee et al[5] in 65 patients and demonstrated that an ONSD of > 0.48 cm corresponded to an ICP> 20 mm Hg. In our patient an elevated ONSD on admission prompted us to initiateanti-edema measures in the form of CRRT, mannitol, hy pertonic saline, etc immediately. Intraoperative ICH has also been demonstrated during OLT especially in the anhepatic phase and reperfusion even in patients who did not exhibit raised ICP preoperatively[12]. Hence, we continued monitoring ONSD at hourly intervals during the intraoperative period as well and noticed a spike in ONSD measurements during the anhepatic phase which settled postreperfusion. Various forms of RRT have been used to treat inborn errors of metabolism in neonates and children. A recent review article on the treatment of liver failure proposed that ammonia clearance could be achieved by using conventional continuous hemofiltration, with higher rates of clearance correlating with higher rates of hemofiltration[14]. The authors cited a study by Slack et al[15]. who conducted one of the first studies evaluating Continuous venovenous hemodiafiltration [CVVHD] in adult patients with liver failure and hyperammonemia. In this prospective cohort study, the investigators examined that there was a meaningful decline in arterial ammonia concentrations with ultrafiltration. The low molecular weight and low plasma protein binding properties of ammonia make it more amenable to dialysis. Even though there isn’t any consensus as to when to initiate CRRT in ALF, we believe it should be implemented early in the progression to hyperammonemia and before the development of AKI, so that the concentration of ammonia will not rise to clinically significant levels. Surges in intracranial pressure could happen during the intraoperative phase also owing to the massive fluid and electrolyte shifts during liver transplantation. So, we decided to continue CRRT during the intraoperative phase too.
Conclusion
correlating with higher rates of hemofiltration[14]. The authors cited a study by Slack et al[15]. who conducted one of the first studies evaluating Continuous venovenous hemodiafiltration [CVVHD] in adult patients with liver failure and hyperammonemia. In this prospective cohort study, the investigators examined that there was a meaningful decline in arterial ammonia concentrations with ultrafiltration. The low molecular weight and low plasma protein binding properties of ammonia make it more amenable to dialysis. Even though there isn’t any consensus as to when to initiate CRRT in ALF, we believe it should be implemented early in the progression to hyperammonemia and before the development of AKI, so that the concentration of ammonia will not rise to clinically significant levels. Surges in intracranial pressure could happen during the intraoperative phase also owing to the massive fluid and electrolyte shifts during liver transplantation. So, we decided to continue CRRT during the intraoperative phase too.
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| How to Cite this Article: Raj A, Shankar V, Kharbhanda M, Goyal N. Peri-Operative monitoring of Optic Nerve Sheath Diameter & early initiation of Renal Replacement Therapy helps in rapid Post-Operative recovery in a patient with Acute Liver Failure post Liver Transplant. Journal of Anaesthesia and Critical Care Case Reports Jan-April 2019;5(1):18-20. |
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