Medical History & Vital Signs

Medical History & Vital Signs

Introduction to Clinical Assessment

A comprehensive medical history and vital signs assessment form the cornerstone of patient safety in dental hygiene. Every clinical appointment must begin with a thorough review of the patient's medical history, followed by the measurement of vital signs. These assessment findings are not merely administrative tasks; they are critical diagnostic tools that allow the dental hygienist to determine the patient's physical status, identify potential risks for medical emergencies, implement necessary treatment modifications, and establish whether dental treatment should proceed or be deferred.

Blood Pressure Classification (ACC/AHA Guidelines)

In 2017, the American College of Cardiology (ACC) and the American Heart Association (AHA) updated the clinical practice guidelines for blood pressure classification in adults. The current standards are defined as:

• Normal: Systolic blood pressure < 120 mmHg and diastolic blood pressure < 80 mmHg.
• Elevated: Systolic blood pressure between 120–129 mmHg and diastolic blood pressure < 80 mmHg.
• Stage 1 Hypertension: Systolic blood pressure between 130–139 mmHg or diastolic blood pressure between 80–89 mmHg.
• Stage 2 Hypertension: Systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg.
• Hypertensive Crisis: Systolic blood pressure > 180 mmHg and/or diastolic blood pressure > 120 mmHg.

Clinical Interpretation of Blood Pressure Readings

When a patient's systolic and diastolic pressures fall into different categories, the higher classification is always used to guide clinical decisions. For example, if a patient's blood pressure is 128/84 mmHg, they are classified as Stage 1 Hypertension because the diastolic pressure (84 mmHg) falls within the Stage 1 range, even though the systolic pressure (128 mmHg) is in the Elevated range.

Dental Treatment Cut-offs and Rationale

Blood pressure values directly dictate the safety of dental care due to the cardiovascular stress induced by dental anxiety, physical discomfort, and the potential systemic effects of vasoconstrictors contained in local anesthetics. The following thresholds must be strictly adhered to:

• Blood Pressure < 160/100 mmHg: Routine dental hygiene care (including scaling, root planing, and selective polishing) may proceed. Stress-reduction protocols should be implemented if the patient exhibits mild anxiety.
• Blood Pressure between 160/100 mmHg and 179/119 mmHg: This is severe Stage 2 hypertension. Elective dental hygiene care must be deferred, and the patient must be referred for a medical consultation. If the patient requires emergency dental treatment for pain or infection, a consultation with their primary care physician is required before any treatment. If emergency treatment proceeds, the clinician must limit the use of epinephrine to the cardiac dose (0.04 mg) or avoid it entirely, and closely monitor vital signs.
• Blood Pressure ≥ 180/120 mmHg: This is a hypertensive crisis. All elective and emergency dental care is strictly contraindicated in the standard dental office. The clinician must immediately stop all procedures, re-measure the blood pressure after 5 minutes, and if it remains at or above this level, refer the patient for immediate medical evaluation. If the patient displays symptoms of target-organ damage (e.g., chest pain, shortness of breath, severe headache, vision changes, or neurological deficits), emergency medical services (EMS) must be activated immediately.

Vital Signs: Pulse, Respiration, and Temperature

Beyond blood pressure, the baseline assessment of pulse, respiration, and body temperature provides vital information regarding the patient's cardiorespiratory status and systemic health.

Pulse (Heart Rate)

The pulse is evaluated by palpating a superficial artery—most commonly the radial artery on the thumb side of the wrist—using the pads of the index and middle fingers. The clinician must assess the rate, rhythm, and quality (amplitude) of the pulse over a minimum of 30 seconds (multiplied by two) or for a full 60 seconds if irregularities are detected.

• Normal Range: The normal resting adult heart rate is 60 to 100 beats per minute (bpm).
• Tachycardia: A pulse rate > 100 bpm. Common causes include anxiety, exercise, fever, dehydration, hyperthyroidism, and cardiovascular stimulants (e.g., caffeine, nicotine, decongestants). Tachycardia increases myocardial oxygen demand and may preclude treatment if accompanied by chest pain or shortness of breath.
• Bradycardia: A pulse rate < 60 bpm. While common in well-conditioned athletes, bradycardia can also indicate sinoatrial node dysfunction, hypothyroidism, or the therapeutic effect of beta-blockers.
• Rhythm and Quality: The rhythm should be regular. An irregular rhythm (such as irregular-irregularity associated with atrial fibrillation) must be noted, and the patient's physician should be consulted. The quality is rated as weak/thready (indicating low cardiac output or dehydration) or strong/bounding (indicating high cardiac output, anxiety, or hypertension).

Respiration

Respiration is assessed immediately after measuring the pulse while keeping the fingers on the radial artery so the patient remains unaware of the count, preventing voluntary alterations in breathing patterns.

• Normal Range: The normal resting adult respiration rate is 12 to 20 breaths per minute.
• Tachypnea: A respiration rate > 20 breaths per minute, which can indicate hyperventilation syndrome, acute asthma exacerbation, COPD, or severe anxiety.
• Bradypnea: A respiration rate < 12 breaths per minute, which may be associated with opioid analgesics, alcohol consumption, or brain stem lesions.
• Quality: The hygienist must observe the depth of chest expansion, the effort required (labored vs. unlabored), and the presence of accessory muscle use. Labored breathing or abnormal sounds (wheezing, stridor) indicate respiratory compromise and require deferral of treatment.

Temperature

Body temperature is typically measured orally using a digital thermometer.

• Normal Range: The normal adult body temperature ranges from 97°F to 99°F (36.1°C to 37.2°C), with the standard average being 98.6°F (37°C).
• Pyrexia (Fever): A body temperature ≥ 100.4°F (38.0°C). A fever is a systemic response to infection, inflammation, or neoplasm. In dental hygiene, elective procedures must be deferred for any patient presenting with an unexplained fever. This policy protects the patient from the metabolic stress of dental care and prevents the dissemination of infectious pathogens (such as influenza, COVID-19, or tuberculosis) through dental aerosols.

ASA Physical Status Classification (ASA I–IV)

The American Society of Anesthesiologists (ASA) Physical Status Classification System is an essential tool for dental clinicians to estimate a patient's overall medical risk and guide treatment planning.

• ASA I: A normal, healthy patient. This patient is non-smoking, has minimal or no alcohol use, and has no systemic disease. They have excellent functional reserve. Treatment modification is not required.
• ASA II: A patient with mild systemic disease. Examples include well-controlled Stage 1 or Stage 2 hypertension, well-controlled type 2 diabetes, mild intermittent asthma, active cigarette smoking, social drinking, pregnancy, or obesity (BMI between 30 and 40). Dental care can proceed, but the clinician should implement basic stress-reduction modifications, such as morning appointments, ensuring the patient has taken their daily medications, and utilizing effective pain control.
• ASA III: A patient with severe systemic disease that limits activity but is not a constant threat to life. Examples include poorly controlled hypertension or type 2 diabetes, stable angina, history of myocardial infarction (MI), stroke (CVA), or transient ischemic attack (TIA) more than 3 months ago, chronic obstructive pulmonary disease (COPD), end-stage renal disease (ESRD) undergoing regular hemodialysis, active hepatitis, pacemaker placement, or morbid obesity (BMI ≥ 40). Dental hygiene treatment requires significant modifications, including pre-operative vital sign monitoring, limiting the dose of vasoconstrictors, utilizing nitrous oxide-oxygen sedation, keeping appointments short, and obtaining a medical clearance from the patient's physician.
• ASA IV: A patient with severe systemic disease that is a constant threat to life. Examples include a history of myocardial infarction, stroke, or TIA within the past 3 months, unstable angina, symptomatic congestive heart failure, severe cardiac valve dysfunction, or ESRD not undergoing regular dialysis. Elective dental hygiene care is strictly contraindicated. If emergency dental care is necessary, it must be performed in a hospital dental clinic or specialized surgical environment with active cardiac monitoring and medical supervision.

Clinical Worked Scenarios and Exam Traps

A frequent test trap involves distinguishing between ASA III and ASA IV classifications based on the timeline of a cardiac event. An MI that occurred 4 months ago makes the patient an ASA III, meaning elective care may proceed with significant modifications. However, an MI that occurred 2 months ago classifies the patient as ASA IV, making all elective care contraindicated. Another trap involves neglecting the highest blood pressure reading; a patient with a blood pressure of 135/102 mmHg is classified as Stage 2 Hypertension due to the diastolic number, and elective treatment must be deferred because the diastolic exceeds 100 mmHg. Clinicians must synthesize all history and vitals rather than relying on a single factor.