Management of anaesthesia in patients with hypertension by Dr Management of anaesthesia in patients with hypertension by Dr. Mohamed Said

Hypertension Why Important ? Common disorder High risk factor for cardiovascular diseases End organ damage – Heart Brain & Kidney Alteration in cerebral & renal blood flow

New classification Borderline 140-159 90-99 Mild 140-159 90-99 Mod. 160-179 100-109 Sever 180-209 110-119 Very sever >210 >120

Main Items Preoperative evaluation Induction of anaesthesia Maintenance of anaesthesia Postoperative management

Preoperative Evaluation Preanesthetic evaluation Perioperative risk reduction Premedication Balanced anesthesia Proper monitoring Parenteral medications

Preanesthetic evaluation History Physical examination Adequacy of blood pressure control

Perioperative risk reduction Effective control of blood pressure Anti Hypertensive drug therapy Hydration Choice of anesthetic agent Adequate analgesia Miscellaneous (psychological support)

Agent Dosage Onset Duration Nitroprusside 0.5 – 10 ug/kg/min 30-60sec Nitroglycerine 1 min 3 – 5mins Esmolol 0.5mg/kg in 1 min 50 – 300 ug/kg/min infusion 12-20 mins Labetolol 5-20 mg 1-2mins 4-8 hrs Propranalol 1-3 mg 1-2 mins 4-6 hrs Trimethaphan 1-6 mg / min 1-3 mins 10-30 mins Fentolamine 1-5 mg 1 – 10 mins 20-40 mins Diazoxide 1-3 mg /kg slowly 2-10 mins 4 – 6 hrs Hydralazine 5-20 mins Nifidepine s/l 10 mg 5-10 mins 4 hrs Methyl dopa 250 – 1000 mg 2-3 hrs 6-12 hrs Nicardipine 0.25 – 0.5 mg 3-4 hrs Enalapril 0.625 – 1 mg10 6-15 mins Fenoldopam 0.1 – 1.6 ug/kg/min 5 mins

1 Urgent reduction of severe acute hypertension Sodium nitroprusside infusion 0.3 – 2 mic.g/kg/min 2 HT with ischemia with poor LV NTG infusion 5 – 100 mic.g/kg 3 HT with ischemia with Tachycardia Esmolol bolus or infusion 50 – 250 micg/kg/min Labetolol bolus orr infusion 2 – 10 mg; 25 – 30 mic. G /kg 4 HT with heart failure Enlapril at 0.5 – 5mg bolus, 1.25 mg/6 hours given over 5 mins. Response within 15 mins 5 HT without cardiac complications Nifidepine – 5 – 10 mg S/l Nicardipine infusion – 5 – 15 mg/hr Hydralazine 5 – 10 mg bolus HT with Phaeochromocytoma Labetolol – Bolus 2 – 10mg Infusion 2.5 – 30 mic g/kg/min Phentolamine 1-4mg bolus

General principles Cardiovascular stability is important during anaesthesia and the perioperative period. Hypertensive patients are at risk of greater swings of blood pressure than the normal population and it has been shown that blood pressure lability can be associated with increased cardiovascular morbidity and mortality postoperatively, particularly in patients with severe uncontrolled hypertension. Patients who have hypertension require a higher blood pressure for adequate organ perfusion than normotensive patients – this is particularly in the elderly. Avoidance of hypotension may prevent complications of under-perfusion..

Induction Significant hypertension in the induction area often settles with a small dose of intravenous sedation (midazolam 1 – 3mg). Persistently elevated blood pressure can prove challenging during anaesthesia. Abrupt and marked reductions in blood pressure may occur on induction of anaesthesia, and large increases during stimulating procedures such as laryngoscopy, intubation and pain. It is possible to augment induction with other pharmacological agents. Short acting opioids such as fentanyl 1mcg/kg with induction agents will diminish stimulatory effects. Intraoperative blood pressure monitoring may be non-invasive or invasive. Standard non-invasive blood pressure monitoring is mandatory for anaesthesia, with a minimal interval of five minutes. High risk patients undergoing major surgery can, in addition, have intra-arterial monitoring to improve control and allow early pharmacological intervention.

Maintenance Patients with underlying organ dysfunction need careful consideration of anaesthetic agents. For example underlying renal failure, will alter metabolism and excretion of drugs. Recent or significant end organ damage, for example recent myocardial infarction may necessitate surgical delay. Effective opioid analgesia, regional anaesthetic techniques and avoiding hypoxia, hypercarbia and light anaesthesia all aid to reduce episodes of hypertension intraoperatively. Vasopressor agents and intravenous fluids may be required if hypotension results from cardiac depression. Spinals or epidurals may increase intraoperative hypotension, particularly in hypertensive patients who are dehydrated or those receiving vasoldilator drugs..

Recovery Monitoring should include ECG, blood pressure and SpO2. Coughing on emergence of anaesthesia may produce hypertension, and preoperative lignocaine spray on the endotracheal tube or deep extubation may improve this. Patients may develop hypertension due to pain, bladder distension or anxiety. It is also important to remember some patients will be confused and disorientated after anaesthesia and this may worsen blood pressure values. This highlights the importance of the recovery room being a suitably calm environment with staff trained to anticipate and treat these problems. After reversible causes have been treated (pain, urine retention) treatment of continuing hypertension may be reaquired.

Postoperative care Patients must be followed up after anaesthesia to ensure post operative complications are minimized and treated appropriately if they occur. It is important to ensure patients continue their antihypertensive after surgery and alternative routes of administration are considered for those patients who are nil by mouth. Patients with severe hypertension must be closely monitored and ward and anaesthetic staff alerted if management becomes difficult or is uncontrolled. High risk patients should also be given supplementary oxygen to prevent hypoxia and therefore reduce ischemic episodes after anesthesia. The continuation of prevention of hypertensive triggers on the ward must also be highlighted.

HOME MASSAGE Patient with diatolic B.P 110 mmHg can do elective surgery but the best make B.P 160/100 is the key number for decision. Premedication for HTN patient is mandatory but avoid oversedation. NO hypotnsive anesthesia for uncontrolled HTN pt. Golden role………keep B.p withen 10%-20% of the preoperative level.

Questions 1-What are the anesthetic goals for hypertensive patients? 2- D.D and management of postoperative hypertension?

Thank you