BLOOD PRESSURE

(Table 2-4)
Many dental procedures are stressful to the patient and may cause an elevation of the blood pressure (Table 2-4).
Also, accidental intravascular injection or rapid absorption (eg, injection into a venous plexus) of local anesthetics containing epinephrine may cause a transient rise in the blood pressure. Dental treatment for patients with hypertension is discussed in Chapter 13, Disease of the Cardiovascular System. Syncope due to anxiety or medications is usually associated with systemic hypotension.



If a patient is receiving treatment for hypertension or if the patient does not regularly visit a physician, blood pressure should be measured before instituting dental treatment. The routine recording of blood pressure in the dental office has been demonstrated to be a valuable method of medical case finding.

Blood pressure should be measured with appropriate equipment and in a standardized fashion(Table 2-5). Although sphygmomanometers are the most accurate devices, validated electronic devices or aneroid sphygmomanometers with appropriately sized cuffs are sufficient for blood pressure screening in dental settings. Finger monitors should not be used.
Electronic devices are usually accurate to within 3% of a manual sphygmomanometer. Their ease of use in comparison with manual sphygmomanometers is a great advantage and encourages increased use. Both blood pressure and pulse are recorded, but irregular rhythms cannot be detected. To detect potential deviations, electronic devices should occasionally be calibrated against a manual sphygmomanometer.
Faulty technique will produce errors.

If the cuff is applied too loosely, if it is not completely deflated before applying, or if it is too small for the patient’s arm, the pressure readings obtained will be erroneously high and will not represent the pressure in the artery at the time of measurement. The one factor mentioned above that is not within the province of the practitioner to change is the arm size. The width of the cuff should be about 40% of the diameter of the patient’s arm, and the bladder length should encircle about 80% of the arm. For patients with unusually large arms, it may be appropriate to use a “thigh” cuff. If a thigh cuff is not available, keep in mind that the readings will be too high. If the cuff is deflated too rapidly (>2–3 mm Hg per heartbeat), the recorded systolic pressure will be erroneously low, and the diastolic pressure will register as too high.