Anesthetic Management of Laparoscopic Surgery for a Patient with a Ventriculoperitoneal shunt Abstract With the advances in the management of hydrocephalus, patients with ventriculoperitoneal shunt are expected to have a normal lifespan. Developments in both instruments and techniques have led to increasing popularity of laparoscopic surgery in every surgical subspecialty. Therefore, it is not uncommon to anesthetize patients with ventriculoperitoneal shunts in the future. The increased intracranial pressure may be present during operation. The anesthetic method of this procedure in this kind of patients was not well established. We now report a patient with a ventriculoperitoneal shunt undergoing laparoscopic cholecystectomy and discuss the anesthetic considerations. Key Words: Laparoscopy-ventriculoperitoneal shunt
Ventriculoperitoneal shunt is the common procedure for relieving intracranial pressure in patients with hydrocephalus. Laparoscopy has also become an important diagnostic and therapeutic tool in many areas of surgery. For the patients with ventriculoperitoneal shunts, it is likely to be performed for laparoscopic surgery. However, the increased abdominal pressure induced by pneumoperitoneum may be concerned to interference the ventriculoperitoneal shunt and induce increased intracranial pressure. The safety of laparoscopy when performed in the patients with ventriculoperitoneal shunts has not been well established. The potential adverse effects and postoperative complications for this procedure may exist [7]. We report the anesthetic method for a patient with a ventriculoperitoneal shunt performed laparoscopic surgery and discuss the potential adverse effects and complications [1-8]. Case Report A 67-year-old male was performed a ventriculoperitoneal shunt 7 years ago due to hydrocephalus. His past history was not significant except the
previous cerebrovascular infarction about 7 years ago. After rehabilitation he was full recovery without any neurological sequelae. He was admitted for laparoscopic cholecystectomy for his acute cholecystitis with cholelithiasis. The previous computed tomography scan of brain about 2 years ago demonstrated multiple old infarctions with no evidence of dilatation of intraventricular system. Before operation neurologist consultation was finished and confirmed the ventriculoperitoneal shunt functioned well. In the operating room, the consciousness of the patient was clear and no signs of increased intracranial pressure were noted. Standard monitors including EKG, pulse oximetry, and noninvasive blood pressure measurement were applied to this patient. Anesthesia was then induced with intravenous thiopental, fentanyl, and intubation was facilitated with intravenous succinylcholine. Anesthesia was maintained with fentanyl and isoflurane in oxygen/air and atracurium was used for muscle relaxation. After induction, an arterial line was inserted for blood gas analysis and continuous blood pressure monitor. Pnemoperaitoneum was therefore created by insufflation of CO 2 and reached intraabdominal pressure to 12 mmhg. Mechanical ventilation was adjusted to achieve a PaCO 2 of 30-35 mmhg. The shunt was clamped by the surgeon at the
distal portion of the peritoneal catheter throughout the whole procedure to prevent the air reflux. The procedure was carried out smoothly after two hours. In the recovery room, he remained hemodynamically stable and no signs of elevated intracranial pressure were noted. Neurological examination including consciousness, muscle power of the extremities, visual change, pupil size and light reflex were performed and revealed negative results. He was transferred to ordinary ward after meeting the discharging criteria of the recovery room. His subsequent hospital course and recovery were uneventful. After two-month postoperative following up, no neurological abnormalities were noted. Three months after surgery he had discomfort sensation over right side extremities and was sent to our emergency department. Brain computed tomography was performed and demonstrated not significantly as compared with the previous computed tomography. He was discharged home two days later. Discussion Ventriculoperitoneal shunt is the major therapeutic tool to release or prevent increased intracranial pressure due to hydrocephalus. Patients with a ventriculoperitoneal shunt are now expected to have a normal life span. With the increasing performance of laparoscopy in surgery, more
patients with ventriculoperitoneal shunt may present for laparoscopy. Open surgery causes some problems in patients with ventriculoperitoneal shunts including shunt infection and abdominal adhesion, with the possibility of distal catheter end entrapment and CSF pseudocyst formation. These lead to subsequent shunt malfunction and revision is needed [1-3]. Laparoscopy decreases these disadvantages in patients with ventriculoperitoneal shunts. The need to insufflate CO 2 to create pneumoperitoneum is the main concern in patients with ventriculoperitoneal shunt. The insufflation pressure is usually maintained between 10-15 mmhg. Every shunt has a one-way valve system to avoid retrograde flow of fluid or gas. The evidences so far indicate that laparoscopy can be done safely without clinical adverse effect [2-5]. However, some adverse effects and complications may exist while laparoscopy performed in patients with ventriculoperitoneal shunts. Uzzo RG et al. [6] described sustained rise in intracranial pressure during pneumoperitoneum in two patients undergoing laparoscopic surgery and cerebrospinal fluid drainage was needed to lower intracranial pressure. The possible explanations for this observation include increased outflow resistance at the distal end of the
shunt and venous outflow obstruction secondary to pneumoperitoneum. They suggested that intraoperative intracranial pressure monitoring is prudent for this subgroup of patients and intracranial hypertension should be treated by cerebrospinal fluid drainage. Furthermore, for the patient with recent established ventriculoperitoneal shunt (10 days before surgery), ventilatory impairment secondary to massive subcutaneous emphysema was also reported [7]. They suggested that recent established ventriculoperitoneal shunt may be a relative contraindication of laparoscopic surgery but the exact time interval has not been established. The one-way shunt valve of the ventriculoperitoneal shunt is very important when the laparoscopy can be performed safely in patients with ventriculoperitoneal shunt. Some surgeon may clamp the shunt to avoid the valve failure [5]. However, Dr.Neale [8] used an in vitro model to assess the potential for failure of shunt valves of a common used shunt. The results revealed that no reflux shown in any of the nine shunts tested to pressures greater than 350 mmhg but different types of ventriculoperitoneal shunts should be tested to confirm the safety of valves. Therefore, the risk of valve failure could not be completely excluded during laparoscopic surgery.
For this patient, it is not necessary for the surgeon to clamp the shunt if the shunt functions well. The possibility of increased intracranial pressure cannot be excluded. Moreover, damage of the shunt catheter can occurred theoretically if improperly instrument is used. Malfunctions of the valve attribute up to 10% of problems needing shunt revision [8]. Therefore, pneumocephalus can still occurred theoretically while laparoscopy performed in a patient with a ventriculoperitoneal shunt consisting of a malfunctioned valve. However, no reports were found in the past. For our patient, we closely followed up the increased intracranial pressure signs and conscious level to avoid the possibility of elevated intracranial pressure. Hypercapnia may occur during pneumoperitoneum and this may deteriorates the potential adverse effects of elevated intracranial pressure in patients with ventriculoperitoneal shunt. Therefore, it is necessary for an anesthesiologist to adjust ventilatory parameters to avoid hypercapnia during pneumoperitoneum. End-tidal CO 2 level should be monitored carefully in these patients. In summary, there are some considerations from anesthetic aspect for patients with ventriculoperitoneal shunt. First, preoperative neurological
evaluations, including shunt evaluation, are indicated for the patients with ventriculoperitoneal shunts. Second, adjust ventilatory parameters to avoid hypercapnia. Third,. Fourth, postoperative neurological and shunt evaluations are also indicated for these patients. Fifth, it is not necessary to clamp the shunt catheter if the shunt functions well. It is important for an anesthesiologist to realize the possible complications of laparoscopy performed in patients with ventriculoperitoneal shunt. Patients with hydrocephalus shunt systems must be kept under close observation in the postoperative period for signs and symptoms that suggest shunt malfunction. Therefore, preoperative neurological evaluation and postoperative neurological observation are critical for these patients. Communication between anesthesiologist, neurosurgeon, and laparoscopic surgeon is important to prevent and treat the theoretically possible but rare complications occurring on patients with ventriculoperitoneal shunts undergoing laparoscopic surgery. References
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