From the Guidelines
A hemoglobin level of 7-8 g/dL is generally considered acceptable for most surgical procedures in otherwise healthy patients, but for patients with cardiovascular disease or those undergoing procedures with anticipated significant blood loss, a higher threshold of 8-10 g/dL may be preferred. The decision to proceed with surgery should be individualized based on the patient's clinical condition, comorbidities, type of surgery, and anticipated blood loss rather than adhering strictly to a specific hemoglobin cutoff. According to the American Association of Blood Banks clinical practice guideline 1, transfusion should be considered at a hemoglobin concentration of 8 g/dL or less or for symptoms such as chest pain, orthostatic hypotension or tachycardia unresponsive to fluid resuscitation, or congestive heart failure. Preoperative anemia increases the risk of perioperative complications including increased mortality, infection rates, and longer hospital stays. If time permits before elective surgery, treating anemia with iron supplementation may be beneficial, as seen in the 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery 1. The body requires adequate hemoglobin to transport oxygen to tissues, and during surgery, the stress response and potential blood loss can further compromise oxygen delivery if baseline hemoglobin levels are already low. Some studies suggest that a hemoglobin level of 9-10 g/dL may be preferred for patients undergoing high-risk surgery, such as neurosurgery or cardiac surgery, as recommended by the American Society of Hematology 2020 guidelines for sickle cell disease: transfusion support 1.
Key considerations for determining the minimum hemoglobin level for surgery include:
- The patient's underlying medical conditions, such as cardiovascular disease
- The type of surgery and anticipated blood loss
- The patient's symptoms, such as chest pain or orthostatic hypotension
- The potential risks and benefits of transfusion.
Overall, the decision to transfuse should be based on a symptom-guided approach, taking into account the individual patient's clinical condition and the potential risks and benefits of transfusion, as recommended by the AABB clinical practice guideline 1.
From the FDA Drug Label
Epogen is indicated to reduce the need for allogeneic RBC transfusions among patients with perioperative hemoglobin > 10 to ≤ 13 g/dL who are at high risk for perioperative blood loss from elective, noncardiac, nonvascular surgery.
The minimum hemoglobin level required to safely undergo surgery is not explicitly stated, but patients with a perioperative hemoglobin level of > 10 to ≤ 13 g/dL may be considered for Epogen treatment to reduce the need for allogeneic RBC transfusions 2. There is no clear minimum hemoglobin level specified in the label for clearing a patient for surgery.
From the Research
Minimum Hemoglobin Level for Surgery
The minimum hemoglobin (Hb) level required to safely undergo surgery is a topic of ongoing debate. According to the study by 3, a restrictive RBC transfusion threshold of 7 g/dL is recommended for hospitalized adult patients who are hemodynamically stable, while a threshold of 8 g/dL is recommended for patients undergoing orthopedic surgery, cardiac surgery, and those with preexisting cardiovascular disease.
Hemoglobin Levels and Surgical Outcomes
- A study by 4 suggests that maintaining hemoglobin or hematocrit values around 11 g/dl or 33%, respectively, is one part of therapeutic interventions that can improve the chances of survival in critically ill patients.
- However, the same study notes that the common denominator underlying different opinions on the general tolerance of anemia is the variable behavior of several "non-Hb variables," which influence the venous oxygen tensions apart from the hemoglobin or hematocrit.
- Another study by 5 found that the adequate Hb concentration capable of covering the oxygen demands of the body depends on several variables measurable at the bedside, and a generally valid 'minimum acceptable hemoglobin concentration' does not exist.
Preoperative Iron Supplementation and Hemoglobin Levels
- A study by 6 found that preoperative iron supplementation with or without erythropoiesis-stimulating agents (ESAs) may reduce red blood cell utilization in patients with preoperative anemia undergoing elective surgery.
- However, the same study notes that the effectiveness of preoperative iron monotherapy in reducing RBC utilization is uncertain, and the administration route of iron therapy (IV vs oral) may differentially affect RBC utilization.
Erythropoiesis-Stimulating Agents and Hemoglobin Levels
- A study by 7 found that erythropoiesis-stimulating agents (ESAs) resulted in a small reduction in the proportion of patients who received one or more RBC transfusions, but the change in Hb concentration was trivial, and the number of serious adverse events and overall short-term mortality were similar between the ESA and control groups.