Management for Hypertension

Pre-operative assessment

• Etiology of hypertension and point in natural history
• Rule out secondary hypertension, especially in young hypertensive
• Age of onset, duration and compliance to treatment

• Current treatment
• identify antihypertensive(s) used
• Check the adequacy of blood pressure control
• Measure erect and supine blood pressure
• Review 4 hourly charting of BP in the ward

• Extent of end organ damage
• CNS system
• History of CVA, TIA
• Fundoscopic examination
• Renal system
• Renal profile
• CVS system
• ECG, CXR
• Further test like echo, stress test if IHD is suspected/diagnosed

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• Acceptability for surgery
• Emergency surgery
• Depends on urgency of surgery
• May require IV antihypertensive ( labetolol, hydralazine) to control BP
• Elective surgery
• Postpone if diastolic BP > 110 mmHG

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Problems associated with uncontrolled HT

• Cardiovascular insatiability leading to
• hypertension during laryngoscopy and intubation
• Hypotension post induction and before surgery
• Dysrrhythmias
• MI
• Cerebral hemorrhage
• Hypertensive encephalopathy

Premedication

• Patient needs to be adequately sedated to avoid large increases in BP secondary to anxiety ( diazepam night before surgery)
• Adequate premedication ( benzodiazepine or I/M narcotic analgesics) should be given, the dose and nature of premedication depending on the patient’s general condition and nature of surgery
• Serve the usual dose of antihypertensive drug on the morning of surgery

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Perioperative management for hypertensive patients

By

Roshnee Kaur Khaira

• No particular anaesthetic agent or technique has been found superior!
• The choice depends on the skill, experience and preference of the anaesthetist.
• Keep in mind! Problems Associated with Uncontrolled Hypertension, which is Cardiovascular Instability.

General Anaesthesia

• Premedication:diazepam, usual dose of anti-hypertensives on morning of surgery.

Monitoring of patient

• Mandatory!
• Continuous monitoring :
• ECG
• Blood Pressure: non-invasive or intra-arterial(depends on nature of surgery)
• Pulse Oximetry
• Options: Capnography, peripheral nerve stimulator, urine output ,temperature

• If patient undergoing a major surgery and with poor left ventricular function?

• Central Venous Pressure
• Pulmonary Artery Catheterisation if required

Induction

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Risk of Cardiovascular Instability

Leads to

• Hypertension during laryngoscopy and intubation
• Hypotension post-induction and before surgery
• Dysrrhythmias
• AMI
• CVA

• Use combination of fentanyl with thiopentone or propofol
• Ketamine is unsuitable: causes hypertension and tachycardia
• Intravenous anti-hypertensives may be needed if before induction if blood pressure is high despite premedication and morning medication.

Laryngoscopy and Intubation

• Obtund Sympathetic responses: options?
• IV fentanyl 1-2ug/kg, IV Lignocaine 1-1.5 mg/kg, beta-blocker, small dose of thiopentone just before intubation
• Allow time for the muscle to relax before attempting laryngoscopy and intubation!
• Best monitored by PNS

Maintenance

• Good oxygenation, normocarbia
• Adequate depth of anaesthesia: narcotic +volatile agent(isoflurane)
• Choice of muscle relaxants: vecuronium, atracurium (cardiovascularly more stable)
• Minimise swings of blood pressure perioperatively

Regional Anesthesia

• Close blood pressure monitoring
• If there is hypotension, aggressive early treatment with fluid challenge and ephedrine
• Make sure regional block works, if pain results from inadequancy can stimulate hypertension and tachycardia
• Be prepared to convert to general anaesthesia if regional block is not adequate

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Remember

• Do not supplement inadequate block with sedation
• Recognise that the patient is hypertensive
• Examine the extend of end organ damage
• Optimize treatment and continue medication
• Minimize swings of blood pressure perioperatively
• Establish adequate monitoring and early aggressive treatment of hypertension: IV labetalol 5-10 mg, IV hydralazine 5 mg

Post-op management

• Continue close BP monitor in recovery room & early post-op period

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• Post-op hypertension is common

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• Causes:
• Respiratory abnormalities
• Pain
• Volume overload
• Bladder distention

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• Complications
• Myocardial ischemia
• Congestive heart failure
• Wound hematoma formation
• Disruption of vascular suture lines

• Always correct those readily reversible contributing causes (with analgesic, catheter…)

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• If uncorrected → Give Parenteral anti-hypertensive

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• IV Nicardipine or sublingual nifedipine is usually used particularly if myocardial ischemia or bronchospasm is suspected.

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• patient should be returned to the ward only when the circulation is stable

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• Preoperative HT medication is restarted when patient resumes oral intakes

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