Which of the following blood pressure readings would be indicative of hypotension (low blood pressure) and potentially suggest reduced cardiac output?

From the Guidelines

Among the given blood pressure readings, 140/60 would most likely indicate reduced cardiac output. This is because the wide pulse pressure (the difference between systolic and diastolic pressures) of 80 mmHg suggests poor peripheral resistance with maintained systolic pressure. In reduced cardiac output states, the body often compensates by increasing peripheral vascular resistance to maintain blood pressure, but this typically narrows the pulse pressure. The other readings (160/100,140/118, and 150/120) all show narrower pulse pressures with elevated diastolic pressures, which are more consistent with increased peripheral resistance rather than reduced cardiac output. Additionally, the relatively lower diastolic pressure of 60 mmHg in the 140/60 reading could indicate the heart's inability to maintain adequate pressure during diastole, another potential sign of compromised cardiac function, as suggested by the guidelines for the diagnosis and management of heart failure in adults 1. According to the European Society of Cardiology's guidelines on the diagnosis and treatment of acute heart failure, cardiogenic shock is characterized by reduced blood pressure and/or low urine output, with a pulse rate > 60 b.p.m. with or without evidence of organ congestion 1. However, it's essential to consider the clinical context and signs of poor cardiac output or hypoperfusion, such as cold clammy skin, cool extremities, decreased urine output, and altered mentation, rather than relying solely on blood pressure values to dictate treatment 1. Key points to consider when evaluating cardiac output include:

• Wide pulse pressure may indicate poor peripheral resistance
• Narrow pulse pressure with elevated diastolic pressure may indicate increased peripheral resistance
• Clinical signs of poor cardiac output or hypoperfusion should guide treatment decisions
• Blood pressure values should be considered in the context of overall clinical presentation, as emphasized by the guidelines 1.

From the Research

Reduced Cardiac Output Indication

The blood pressure that would suspect a reduced cardiac output is:

• 140/60 This is because a diastolic blood pressure of less than 60 mmHg has been associated with increased risk of cardiovascular events, as reported in a study published in the JAMA network open 2.

Blood Pressure Ranges and Cardiac Output

Other blood pressure ranges provided do not directly indicate reduced cardiac output:

• 160/100: This blood pressure is elevated, but there is no direct evidence to suggest reduced cardiac output based on this value alone.
• 140/118: This diastolic blood pressure is actually higher than what is typically considered normal, and does not indicate reduced cardiac output.
• 150/120: Similar to the previous point, this blood pressure is elevated, but does not directly indicate reduced cardiac output.

Relationship Between Blood Pressure and Cardiac Output

It's worth noting that the relationship between blood pressure and cardiac output is complex, and reduced cardiac output can occur at various blood pressure ranges. However, based on the provided evidence, a diastolic blood pressure of less than 60 mmHg is associated with increased risk of cardiovascular events, which may be related to reduced cardiac output 2.

Additional Considerations

Other factors, such as the use of beta-blockers and ACE inhibitors, can also impact cardiac output and blood pressure. Beta-blockers have been shown to be effective in treating heart failure and reducing mortality, while ACE inhibitors have been used to treat hypertension and heart failure 3, 4, 5, 6. However, these factors are not directly related to the specific blood pressure values provided.