How often do anesthesiologists have reliable baseline Blood Pressures (BPs) to guide therapy in cervical spine surgery?

Reliability of Baseline Blood Pressure Measurements in Cervical Spine Surgery

Anesthesiologists frequently lack reliable baseline blood pressure measurements to guide therapy in cervical spine surgery, as operating room measurements are typically elevated and do not reflect true baseline values. 1

Challenges in Obtaining Reliable Baseline BP

• Pre-operative anxiety and stress commonly elevate blood pressure readings taken in the operating room setting
• The American Society of Anesthesiologists (ASA) recommends assessing baseline blood pressure on a case-by-case basis using measurements taken prior to entering the operating room 1
• Operating room measurements are typically elevated and do not reflect true baseline values, making them unreliable for guiding intraoperative management 1

Current Guidelines and Recommendations

The ASA Task Force on Perioperative Visual Loss provides specific recommendations regarding blood pressure management during spine surgery:

• Continually monitor systemic blood pressure in high-risk patients, particularly those undergoing prolonged procedures or with substantial blood loss 2
• Assess baseline blood pressure on a case-by-case basis 2
• Determine whether deliberate hypotension should be used in high-risk patients on a case-by-case basis 2
• Check for pre-operative hypertension, its degree of control, and pre-operative use of anti-hypertensive drugs before using deliberate hypotension 2

Best Practices for Establishing Baseline BP

To improve reliability of baseline measurements:

1. Use pre-surgical measurements: Blood pressure readings from the patient's last office visit or pre-surgical evaluation provide more reliable baseline values than operating room measurements 1, 3

2. Multiple readings: The British Hypertension Society recommends using multiple readings to establish baseline blood pressure, which can be obtained during pre-surgical evaluation or in the holding area before entering the operating room 1

3. Standardized environment: Measure blood pressure in a relaxed, temperate setting with calibrated equipment, with the patient seated and arm supported for at least one minute before the initial reading 2

4. Bilateral measurements: For vascular or renal surgery patients, measure blood pressure in both arms 2

Implications for Intraoperative Management

Lacking reliable baseline measurements can lead to:

• Inappropriate vasopressor management
• Increased risk of perioperative visual loss associated with blood pressure fluctuations 2
• Challenges in determining when deliberate hypotension is appropriate
• Difficulty maintaining appropriate pressure ranges (typically 75-140% of baseline) 1

Common Pitfalls to Avoid

• Relying solely on operating room measurements: These are often elevated due to anxiety and do not reflect true baseline 1
• Using post-surgical blood pressures to determine pre-surgical baseline: This approach is fundamentally flawed and contradicts established guidelines 1
• Failing to consider pre-existing hypertension: Patients with hypertension require higher arterial pressure maintenance to prevent end-organ damage 2
• Not discussing blood pressure management with the surgical team: The ASA strongly recommends discussing with the surgeon if deliberate hypotension is necessary 2

By following these guidelines and obtaining reliable baseline blood pressure measurements before cervical spine surgery, anesthesiologists can better guide therapy and potentially reduce the risk of perioperative complications.