Large-caliber peripheral intravenous (IV) access is the preferred route of access in this patient with a hemodynamically significant gastrointestinal bleed. She requires emergent fluid resuscitation because of her bleeding and intravascular volume depletion. When large volumes of crystalloid fluid and blood are needed quickly, large-caliber, shorter catheters allow the highest flow rates to be achieved. Flow of fluid through a catheter is inversely proportional to catheter length and proportional to the radius of the catheter to the fourth power. Therefore, the highest flow rates may be achieved through shorter, large-bore catheters. Peripheral IV catheters are typically significantly shorter than either catheters used for central access or peripherally inserted central catheters. Peripheral IV catheters may also be significantly larger than most central catheters, allowing for increased fluid flow. For example, potential flow rates for a 14-gauge (1.73-mm inner diameter) catheter are approximately 3 times greater than an 18-gauge (0.95-mm inner diameter) catheter of equal length. For this reason, use of larger, shorter peripheral catheters is preferred for fluid resuscitation in patients requiring emergent treatment.
Although central access remains a way to administer fluids, it is not recommended for rapid volume infusion. Therefore, a single-lumen peripherally inserted central venous catheter or triple-lumen internal jugular venous catheter would not be appropriate for this patient who requires large fluid volumes quickly. Central access may ultimately be necessary to administer vasopressor therapy, which cannot be given through peripheral access, if this patient does not respond to fluid resuscitation.
Intraosseous infusion is an immediate alternative in medical or trauma resuscitation when other forms of access cannot be rapidly obtained. Sites for intraosseous access in adults include 1 to 2 cm below the tibial tuberosity and the humeral head. Alternative access should replace the intraosseous access catheter within approximately 24 hours of placement to minimize complications.