What is the nitroglycerin (NTG) bolus dose for acute uncontrolled hypertension in a patient undergoing myomectomy?

From the Guidelines

For acute uncontrolled hypertension during myomectomy, nitroglycerin (NTG) should be administered as an IV bolus of 50-100 mcg, which may be repeated every 3-5 minutes as needed, based on the most recent guidelines from the American College of Cardiology/American Heart Association joint committee on clinical practice guidelines 1. The dose should be titrated based on blood pressure response, with careful monitoring to avoid excessive hypotension.

• Key considerations include:
  • Maintaining continuous blood pressure monitoring
  • Having fluids readily available to manage potential hypotension
  • Being aware that tachyphylaxis can develop with prolonged use, and patients may require increasing doses to maintain the same effect
• The American College of Cardiology/American Heart Association guidelines emphasize the importance of managing hypertension in the perioperative period, particularly in patients with preinduction systolic blood pressure >160 mm Hg and ≥1 components of the RCRI 1.
• NTG works by causing venous and arterial vasodilation through release of nitric oxide, reducing preload and afterload, which decreases myocardial oxygen demand and lowers blood pressure rapidly, making it particularly useful in the surgical setting where quick blood pressure control is needed.
• A continuous infusion may be initiated at 0.5-10 mcg/kg/min following bolus doses if sustained control is needed, with careful monitoring of blood pressure and adjustment of the dose as necessary.

From the Research

Nitroglycerin (NTG) Bolus Dose for Acute Uncontrolled Hypertension

• The provided studies do not specify a bolus dose of nitroglycerin (NTG) for acute uncontrolled hypertension in a patient undergoing myomectomy 2, 3, 4, 5, 6.
• However, it is mentioned that intravenous nitroglycerin is useful in patients prone to myocardial ischemia, but should be avoided in patients with increased intracranial pressure 2.
• In a comparative study on nitroglycerine versus dexmedetomidine infusion for controlling accidental intraoperative uncontrolled hypertension, nitroglycerine infusion was administered at a dose of 0.3 - 1 µg/kg/min 3.
• The use of nitroglycerin as a first-line option for patients with hypertensive emergencies is discussed, although its potential adverse effects and difficulties in use are well known 5.

Perioperative Hypertension Management

• Strategies for managing perioperative hypertension include careful evaluation prior to surgery to identify the underlying cause of hypertension, and selection of the best treatment option 4.
• Therapeutic options during and after surgery include sodium nitroprusside, esmolol, and nicardipine, among others 4.
• The pharmacological management of hypertensive emergencies and urgencies may involve the use of newer agents such as clevidipine, a third-generation dihydropyridine calcium-channel blocker 5.

Myomectomy and Hypertension

• Myomectomy is associated with perioperative bleeding, and the use of intramyometrial vasopressin may decrease blood loss and blood transfusion, but is also associated with cardiovascular complications 6.
• The incidence of hypertension, bradycardia, and atrial extrasystole was higher with vasopressin than the control group in a study assessing the perioperative effect of vasopressin in patients undergoing laparoscopic myomectomy 6.