What is the role of inotropes, such as norepinephrine (noradrenaline) or epinephrine (adrenaline), in managing hypotension in trauma patients undergoing surgery?

From the Guidelines

Inotropes, such as norepinephrine, play a crucial role in managing hypotension in trauma patients undergoing surgery, and their use should be guided by optimal intravascular volume achievement and a mean arterial pressure (MAP) target of at least 65 mmHg, as recommended by recent guidelines 1.

Importance of Inotropes in Trauma Patients

The use of inotropes in trauma patients during surgery is critical for maintaining adequate blood pressure and tissue perfusion.

• Norepinephrine is typically the first-line vasopressor, usually started at 0.05-0.1 mcg/kg/min and titrated to maintain a MAP of at least 65 mmHg, as it has both vasoconstrictor effects and some beta-agonism to support cardiac contractility 1.
• Epinephrine (0.05-0.5 mcg/kg/min) may be added for additional inotropic support when hypotension persists despite adequate fluid resuscitation and norepinephrine 1.

Key Considerations

• The goal of using inotropes is to maintain organ perfusion while definitive surgical control of bleeding and resuscitation with blood products occurs, as prolonged vasopressor dependency without addressing the root cause can lead to end-organ damage and increased mortality 1.
• Continuous hemodynamic monitoring is necessary during administration, and these medications should be delivered through a central venous catheter whenever possible to prevent tissue damage from extravasation 1.
• It's essential to address the underlying cause of hypotension (hemorrhage, tension pneumothorax, cardiac tamponade) while using vasopressors as a temporizing measure 1.

Recent Guidelines and Recommendations

• The ERAS society recommendations for perioperative care in emergency laparotomy suggest guiding the use of inotropes and vasopressors once optimal intravascular volume has been achieved, and using minimally invasive cardiac output devices to calculate values for stroke volume, stroke volume variation (SVV), pulse pressure variation (PPV), and cardiac index 1.
• A recent study in the UK found that targeting a MAP of 60 mmHg instead of 65 mmHg did not result in significant differences in 90-day mortality, but higher doses of vasopressors to target higher MAPs may reduce the risk of AKI but increase the risk of mortality 1.

From the FDA Drug Label

For blood pressure control in certain acute hypotensive states (e.g., pheochromocytomectomy, sympathectomy, poliomyelitis, spinal anesthesia, myocardial infarction, septicemia, blood transfusion, and drug reactions). To provide hemodynamic support in septic shock associated hypotension in adult patients, the suggested dosing infusion rate of intravenously administered epinephrine is 0.05 mcg/kg/min to 2 mcg/kg/min, and is titrated to achieve a desired mean arterial pressure (MAP).

The role of inotropes, such as norepinephrine or epinephrine, in managing hypotension in trauma patients undergoing surgery is to provide hemodynamic support.

• Epinephrine is used to increase blood pressure in cases of septic shock associated hypotension.
• Norepinephrine is used for blood pressure control in certain acute hypotensive states. The dosage of inotropes should be titrated to achieve a desired mean arterial pressure (MAP) 2, 3. Key points to consider when using inotropes in trauma patients undergoing surgery include:
• Dosing: The suggested dosing infusion rate of intravenously administered epinephrine is 0.05 mcg/kg/min to 2 mcg/kg/min 2.
• Titration: The dosage may be adjusted periodically to achieve the desired blood pressure goal 2.
• Monitoring: Patients should be closely monitored for changes in blood pressure and other hemodynamic parameters.

From the Research

Role of Inotropes in Trauma Patients Undergoing Surgery

The use of inotropes, such as norepinephrine (noradrenaline) or epinephrine (adrenaline), plays a crucial role in managing hypotension in trauma patients undergoing surgery. The primary goal of inotrope therapy is to restore adequate tissue perfusion and normalize cellular metabolism 4.

Benefits and Risks of Inotropes

• Inotropes, such as dobutamine, can increase cardiac output and improve tissue perfusion 4, 5.
• Norepinephrine is often used as a first-line vasopressor due to its lower risk of adverse events compared to other catecholamine vasopressors 4.
• Epinephrine may be used for inotropic support, but high doses carry an excessive risk of adverse events 4, 6.
• The use of vasopressors, including inotropes, should take into account both arterial pressure and tissue perfusion when choosing therapeutic interventions 4, 7.

Clinical Evidence and Guidelines

• Studies have shown that vasopressor use is relatively common in severely injured patients requiring emergency operative intervention, and is associated with mortality 6.
• However, the use of vasopressors, including inotropes, may be beneficial in traumatic shock resuscitation to counteract vasodilation and maintain organ perfusion 7.
• Current guidelines suggest that norepinephrine may be preferred over epinephrine in patients with cardiogenic shock, and dobutamine represents the first-line inotrope agent when norepinephrine fails to restore perfusion 5.

Key Considerations

• The pathophysiology of traumatic shock is complex and involves multiple neurohormonal interactions, making it essential to target an appropriate balance between intravascular volume and vascular tone 7.
• Excessive volume resuscitation is associated with adverse clinical outcomes, and vasopressors may be useful in traumatic shock resuscitation to maintain organ perfusion 7.
• Further research is needed to determine the optimal use of inotropes and vasopressors in trauma patients undergoing surgery, including the choice of agent, therapeutic end points, and safe and effective doses 8.