Preoperative Management of Hypertension

Approximately 50% of adults in the United States suffer from hypertension, or high blood pressure [1]. The ubiquity of the disease, combined with its associated complications, helps explain why hypertension is the second most common risk factor associated with surgical morbidity [2]. Preoperative management of hypertension can be a highly effective means of preventing or reducing morbidity [2]. To successfully manage a patient’s hypertension, clinicians must conduct comprehensive preoperative evaluations, design patient-appropriate lifestyle and/or pharmacological regimens, and postpone surgery if necessary.

During the preoperative examination, physicians must determine whether the patient is a viable candidate for surgery. To properly assess the risks associated with anesthesia, teams must pay careful attention to medical issues related to hypertension [3]. These include renal failure, cerebrovascular disease, and ischemic heart disease [3]. Furthermore, clinicians should measure blood pressure during a comprehensive physical examination to identify asymptomatic hypertension patients [3]. Assessing patients’ physical exercise tolerance and hypertension-induced organ damage can determine whether further cardiac testing is necessary [4].

Specific examinations can be useful for detecting conditions that increase risk during surgery or anesthesia, such as urine testing for microalbuminuria, a 12-lead echocardiogram (EKG), and a full blood count [5]. Additionally, patients’ serum uric acid, sodium, potassium, and creatinine levels, along with cholesterol, should all be measured [5]. Recent studies have called into question the necessity of EKG before noncardiac surgery [6]. One such experiment followed 997 asymptomatic hypertensive patients before surgery, where only half received a preoperative EKG [6]. There was no significant difference in outcome between the two groups, suggesting that EKG may not be a necessary component of the preoperative routine for this patient population [6]. Clinical teams should decide whether to administer an EKG on a case-by-case basis.

After collecting this information, clinicians can decide on the optimal pharmacological regimen for their patients. Pharmacology should be turned to if lifestyle modifications are insufficient for lowering the patient’s blood pressure [7]. Often, a mild dose of thiazide-type diuretics serves as an effective initial therapy [7]. According to the patient’s response to the diuretics, additional medications may be prescribed, including angiotensin II receptor antagonists, calcium-channel blockers, and angiotensin-converting enzyme inhibitors [7]. Clonidine, phenytoin, and β-blockers can prevent perioperative dysrhythmia and hypertension [2]. Additionally, nasal nifedipine can acutely control a patient’s blood pressure before surgery [2].

When blood pressure cannot be controlled, physicians have a few options. For one, surgery can be postponed [2]. Some studies suggest that postponement should occur when a patient’s diastolic blood pressure (DBP) is higher than 110 mmHg [2]. However, recent experiments indicate that delays are not always necessary: intranasal nifedipine can reduce a patient’s DBP to avoid rescheduling, although patients who do not delay their surgeries may be hospitalized longer [2]. Depending on the patient’s response to presurgical drugs, history, and comorbidities, postponement may be appropriate.

Preoperative management of hypertension requires consideration of various factors, including patient history, examination results, the severity of disease, and type of operation. Fortunately, hypertension can carry a low risk of complication if these concerns are all addressed.

References 

[1] CDC, “Facts About Hypertension in the United States,” Centers for Disease Control and Prevention, September 2020. [Online]. Available: https://bit.ly/2PHJnx4. 

[2] N. Weksler et al., “The dilemma of immediate preoperative hypertension: to treat and operate, or to postpone surgery?,” Journal of Clinical Anesthesia, vol. 15, no. 3, p. 179-183, May 2003. [Online]. Available: https://doi.org/10.1016/S0952-8180(03)00035-7. 

[3] M. A. Daabiss, “Perioperative hypertensive crisis – the anaesthetic implications. A Review of Literature,” British Journal of Medical Practitioners, vol. 9, no. 3, p. 1-9, September 2016. [Online]. Available: https://www.bjmp.org/content/perioperative-hypertensive-crisis-anaesthetic-implications-review-literature. 

[4] D. R. Spahn and H.-J. Priebe, “Editorial II: Preoperative hypertension: remain wary? ‘Yes’–cancel surgery? ‘No’,” British Journal of Anaesthesia, vol. 92, no. 4, p. 461-464, April 2004. [Online]. Available: https://doi.org/10.1093/bja/aeh085. 

[5] S. J. Howeel, ” Preoperative hypertension,” Current Anesthesiology Reports, vol. 8, p. 25-31, February 2018. [Online]. Available: https://doi.org/10.1007/s40140-018-0248-7. 

[6] L. W. F. Ramos et al., “What is the Importance of Preoperative Electrocardiogram in Hypertensive Patients for Moderate/High Risk Noncardiac Surgery? A Single-Center Randomized Study,” Journal of the American College of Cardiology, vol. 69, no. 11, p. 2539, March 2017. [Online]. Available: https://doi.org/10.1016/S0735-1097(17)35928-4.  

[7] S. Hanada et al., “Hypertension and anesthesia,” Current Opinion in Anesthesiology, vol. 19, no. 3, p. 315-319, June 2006. [Online]. Available: https://doi.org/10.1097/01.aco.0000192811.56161.23.