Dental management of the hypertensive adult patient

Originally published in the August/September 2016 issue of Dispatch

Hypertension is defined as a sustained elevation of systolic and/or diastolic blood pressure and represents a significant risk factor for cardiovascular and renal disease. Classification of blood pressure in adults can be found in Figure 1. Information is available elsewhere that reviews the classification and management of hypertension in children and adolescents.

Figure 1. Classification of blood pressure for adults

Blood Pressure Classification SBP mmHg DBP mmHg 
Normal <120 and <80 
Prehypertension 120–139 or 80–89 
Stage 1 Hypertension 140–159 or 90–99 
Stage 2 Hypertension ≥160 or ≥100 

SBP, systolic blood pressure; DBP, diastolic blood pressure

Hypertension Canada estimates that approximately 23 per cent of Canadian adults are affected by hypertension. Given its high prevalence, dentists are likely to encounter patients who have hypertension and perhaps one or more of its many possible complications. Such patients frequently have other medical conditions and/or risk factors and may be taking several medications, including antihypertensive drugs. Knowledge of the therapeutic effects, possible drug interactions and side effects of all medications is essential.

Hypertension may be asymptomatic, so patients may be unaware that they have the disease and remain untreated. Although dentists do record blood pressure readings at various times, it is not considered within the scope of practice of dentistry to diagnose hypertension. Dentists are in an ideal position, however, to both screen for patients who may have undiagnosed hypertension and recognize those with a previous diagnosis whose blood pressure may not be under control. Patients may then be referred to their physician for evaluation. Several risk factors exist for development of hypertension including age, obesity, dietary sodium intake, obstructive sleep apnea, as well as many others.

A comprehensive medical history, including a Review of Systems (ROS) where indicated, is necessary for the provision of safer dental treatment. Medical consultation may be needed to confirm the presence, severity and stability of the patient’s condition(s). This will assist dentists in their decisions regarding the type and timing of dental treatment and what precautions, if any, are required.

Most patients who have a prior medical diagnosis of high blood pressure will present with primary (or essential) hypertension and have no specific cause for their disease. A minority of patients will have been diagnosed with secondary hypertension, in which an underlying condition, such as chronic renal disease, Cushing disease or a thyroid disorder, is present.

Blood pressure readings are not required for every patient at every appointment. Consideration should be given to:

• the patient’s age, medical history, level of anxiety and present state of health;
• the complexity of forthcoming dental treatment;
• whether sedation or general anesthesia is contemplated.

In general, it may be prudent to take baseline blood pressure readings for all new adult patients. Repeated readings at recall and/or other appointments may be considered for patients with a prior diagnosis of hypertension, and particularly for those who may be non-compliant with suggested therapy, those with poorly controlled disease and/or those who have other conditions, such as history of stroke, renal disease, diabetes, heart failure or myocardial infarction.

Upon arriving at the office, many patients will have the opportunity to rest for a period of time in the waiting room before their dental appointment. In situations where the clinical staff are ready to see the patient right away, blood pressure should not be taken immediately. As a result of the patient’s physical activity, artificially high readings may result; blood pressure measurement is best delayed for at least five minutes from arrival. Measurement should take place with the patient seated, the arm supported at heart level and no clothing present under the cuff.

Many factors influence the accuracy of blood pressure readings, including technique, cuff size, the patient’s body/arm position, type of measurement device, “white coat” effect, room temperature, and the patient’s recent use of alcohol, caffeine or nicotine. Two measurements at one minute intervals should be taken and the average documented. Additional readings may be necessary for some circumstances.

Once blood pressure is taken, a decision to proceed with treatment will depend on the systolic and/or diastolic readings, the presence of various risk factors, the anticipated procedure, and the health of the patient. Reasonable professional judgement must be exercised, taking account of the particular patient circumstances. Although individual blood pressure readings may serve as general guidance, dentists should be wary of over-reliance on specific numerical values to direct clinical decisions.

Dentists are encouraged to seek medical advice whenever uncertainty exists regarding the health of the patient. For certain patients, such as an anxious, medically compromised individual undergoing a more stressful procedure, the dentist may elect to provide treatment with continuous monitoring of vital signs. In other cases, it may be best to refer the patient to a hospital dental clinic setting or delay treatment pending further medical advice. In addition, some patients may require more urgent medical evaluation.

As for all patients with cardiovascular disease receiving dental treatment, it is advisable to implement a stress reduction protocol, including shorter appointments, effective local anesthesia (limiting epinephrine to 0.04 mg) and possible use of sedation. In addition, consideration should be given to taking blood pressure readings before and after administration of local anesthetic, as well as continuous monitoring of vital signs throughout the procedure. Dentists administering sedation or general anesthesia must comply with requirements for patient monitoring, as described in the College’s Standard of Practice on the Use of Sedation and General Anesthesia in Dental Practice.

Dentists should be aware that certain drugs, including some recreational drugs, may potentiate the effects of a vasoconstrictor. In addition, chronic use of NSAID’s may result in interaction with some antihypertensive medications, possibly resulting in an increased blood pressure. Patients may also experience orthostatic hypotension as they are raised from a reclined position.

Further information related to guidelines on detection, treatment and control of hypertension can be found on the website of Hypertension Canada’s Canadian Hypertension Education Program (CHEP).

A list of recommended devices used for taking blood pressure readings can be found at www.dableducational.com, which is also available as a link through the CHEP website.

ADDITIONAL RESOURCES:
The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure Classification (JNC 7), NHLBI, NIH.