Use of TIVA for Mandibular Plating in a Patient with Takayasu's Disease.

Sir,

Takayasu's arteritis is a rare, chronic progressive panendarteritis involving aorta and its main branches. Anesthetic management for this condition has been described in literature mainly for caesarian section or aortic /artery bypass procedures. We want to share our experience of elective procedure of mandibular plating under mandibular nerve block and TIVA.

A 35- yr male presented with spontaneous fracture of mandible for plating of fractured segments. History of epilepsy for last 5 years for which he took treatment. On examination radial pulses absent, carotid pulse were very feeble & irregular. Pulse rate in lower limb was - 74/min, blood pressure unrecordable on upper limbs, lower limb blood pressure was 210/120 mm Hg. Chest & cardiovascular system were essentially normal. Fundus examination was essentially normal except B/L mild chorioretinal degeneration. Patient's hemoglobin was 12.3, TLC7500,DLC-N-67, L-28, M-1, E-4, Platelet count 3.18 lac/mm3, ESR 43, CRP 9.4 mg/l, PTI-100%, viral markers negative, liver function test-WNL, echocardiography-good systolic function , EF 60 %, no valvular lesion seen. MR angiography showed normal aorta, marked thickening of bilateral brachiocephalic extending upto bilateral common carotid, bilateral subclavian, bilateral axillary artery, collaterals seen in head, neck and chest, brain vessels getting supply through posterior circulation; right renal artery normal, left renal artery showing moderately severe stenosis. This was consistent with type III Takayasu. Preoperatively patient was stabilized on tab predisolone 40 mg once daily, tab ranitidine 150 mg twice daily, tab ramipril 5 mg twice daily.

There was past history of dental extraction 3 years back when he was diagnosed having takayasu's disease. Two years back he developed osteomylitis & resorption of mandible for which debridement was done under local anaesthesia.

Patient was premedicated with inj tramadol 100 mg intramuscularly 30 min prior to surgery. In the operating room, the patient was connected to routine monitors and i.v. line established using ringer lactate. Conscious sedation with inj midazolam 2mg bolus & in the increments of 1 mg /min was given till patient was sedated but conscious. Mandibular nerve block was given using 3 ml of plain 2% xylocaine. Oxygen was administred through nasopharyngeal airway. After achieving adequate analgesia, procedure was started but when the fracture realignment was attempted, heart rate increased to 140/min, patient became uncomfortable and better relaxation was required. There was choice to use GA with endotracheal intubation or total intravenous anaesthesia (TIVA). GA was avoided as it might have produced pressure responses, moreover the facility of high end monitoring and BIS was not available in dental wing. So TIVA was given using inj propofol in the bolus dose of 50 mg and further incremental doses of 10 mg (total 70 mg). After fracture realignment, introsseous wiring was carried out. Throughout the TIVA administration pulse, blood pressure and ECG were stable. Continuous suction was used in the cheek area. At the end of the procedure patient was awake and was observed in the ICU of dental college with no untoward effect for 2 days.

Takayasu's Arteritis (TA), is a chronic progressive obstructive panarteritis of unknown aetiology. The most serious effect of aortoarteritis is thickening, stenosis and shortening of affected arteries (supra aortic, renal and pulmonary arteries) which interferes with blood flow to the organs supplied and is also associated with widespread aneurysm and thrombus formation . TA has been classified as on the bases of vessel involvement or depending on the presence of four major complications i.e., hypertension, retino pathy, aneurysm formation and aortic regurgitation.1

Preoperative assessment of a patient with Takayasu's disease must take into account the degree of organ involvement with special attention to cardiac, pulmonary, renal and cerebral function, in addition the drugs used for treatment of the disease.1 The influence of changing head positiion on cerebral function should be evaluated during the preoperative visit, because hyperextension of the neck or incorrect positioning of the head may compromise blood flow through shortened and obstructed carotid arteries.2

Choice of anaesthesia technique should take into consideration maintenance of adequate arterial perfusion pressure in perioperative period. It should be based on the knowledge of the location pathophysiology of vascular lesions.3

General Anaesthesia has the advantage that it doesn′t cause sudden fall in BP. However, acute hypertensive crisis with disastrous consequences could occur during laryngo-scopy, intubation and extubation.4 There can be cerebral hemorrhage and infarction or cardiac dysfunction in a patient with TA.5

Regional anaesthesia wherever possible will be preferable as it avoids the various side effects related to general anaesthesia. It is also associated with sympath-etic block and decrease in blood pressure which further compromises regional circulation in the stenosed arteries.5

Our patient had type III of disease, so in order to avoid the complications related to GA, we planned a combination of mandibular nerve block and conscious sedation but had to supplement with TIVA in order to achieve smooth level of anaesthesia. At the same time we could avoid the stress of intubation & extubation. However, hypotension may exaggerate with drugs such as propofol or midazolam, so they must be given to these patients with caution.5

Intraoperative monitoring is very important in these cases. Cerebral infarction has been reported after general anaesthesia.4 We used ECG, pulse oximetery & NIBP for intraoperative monitoring, although various other devices like EEG, BIS, Doppler monitoring, have been used by various authors, but these facilities were not available at our dental wing. In procedures where it is possible to keep the patient awake, it is the most simple and reliable monitor for judging adequate cerebral perfusion.

Regional anaesthesia is considered advantageous over general anaesthesia. Giving local block has additional benefit of avoiding complications such as hypotension etc. associated with central neuraxial block.