From the Guidelines
Low hemoglobin in emergency situations is commonly caused by acute blood loss from trauma, gastrointestinal bleeding, surgical complications, or obstetric hemorrhage, and management depends on the severity and cause, with a focus on addressing the underlying cause and restoring oxygen-carrying capacity. The causes of low hemoglobin in emergency situations can be categorized into several key areas, including:
- Acute blood loss from trauma, gastrointestinal bleeding, surgical complications, or obstetric hemorrhage
- Hemolysis (destruction of red blood cells)
- Bone marrow suppression
- Nutritional deficiencies
- Chronic diseases
Management of low hemoglobin in emergency situations typically begins with addressing the underlying cause while simultaneously restoring oxygen-carrying capacity. For critical patients with active bleeding and hemodynamic instability, immediate blood transfusion with packed red blood cells (PRBCs) is indicated, typically starting with 1-2 units and reassessing 1. The traditional transfusion threshold is hemoglobin below 7 g/dL for most patients, or below 8-9 g/dL for those with cardiac disease or ongoing bleeding, as supported by the most recent guideline from 2019 1. Volume resuscitation with crystalloids (normal saline or lactated Ringer's) at 1-2 liters initially helps maintain blood pressure while blood products are prepared. Hemostatic measures are essential, including direct pressure, surgical intervention, or endoscopic procedures depending on the bleeding source. Tranexamic acid (1g IV over 10 minutes, followed by 1g over 8 hours) should be administered within 3 hours of trauma with significant bleeding. For non-bleeding patients with chronic anemia, iron supplementation (ferrous sulfate 325mg three times daily), vitamin B12 (1000mcg daily), or folate (1mg daily) may be appropriate based on the underlying cause, as suggested by recent studies 1. Point-of-care testing for hemoglobin levels and coagulation parameters guides ongoing management, while continuous monitoring of vital signs, urine output, and mental status helps assess the adequacy of resuscitation efforts.
In terms of specific management strategies, the use of erythropoiesis-stimulating agents may be recommended in critically ill anemic patients, especially those with a history of ischemic cardiovascular disease and/or venous thromboembolism, to reduce red blood cell utilization and decrease mortality 1. However, the decision to use these agents should be made on a case-by-case basis, taking into account the individual patient's underlying condition and potential contraindications. Overall, the management of low hemoglobin in emergency situations requires a multifaceted approach that addresses the underlying cause, restores oxygen-carrying capacity, and minimizes the risk of complications.
From the Research
Causes of Low Hemoglobin in Emergency Situations
- Trauma 2, 3
- Sepsis 2, 4
- Gastrointestinal bleeding 2, 5
- Iron deficiency 3
- Suppression of erythropoietin and iron transport 3
- Coagulopathies 3
- Adverse effects of and reactions to medications 3
- Stress-induced gastrointestinal bleeding 3
- Disseminated intravascular coagulation 4
- Capillary stopped-flow 4
- Restriction of glucose to red blood cells 4
- Changes in red blood cell membrane properties 4
- Hemolytic pathogens 4
- Red blood cell apoptosis 4
Management of Low Hemoglobin in Emergency Situations
- Transfusion of red blood cells (RBCs) is the primary management of anemia 2
- A restrictive threshold of 7 g/dL is recommended in the new American Association of Blood Banks guidelines and multiple meta-analyses 2
- The physician must consider the patient's hemodynamic status, comorbidities, risks and benefits of transfusion, and clinical setting in determining the need for transfusion 2
- Iron is an alternative treatment for patients with microcytic anemia owing to iron deficiency 6
- Hyperbaric oxygen is an option for alternative rescue therapy 6
- Most patients with chronic anemia may be discharged with follow-up if hemodynamically stable 6