Volume Resuscitation Periprocedural Care

Updated: Jul 07, 2016
  • Author: Jeromy T Boucher, DO; Chief Editor: Erik D Schraga, MD  more...
  • Print
Periprocedural Care

Patient Education & Consent

Elements of informed consent

Informed consent for a blood product transfusion requires an appreciation of both benefits and risks. Often, the patient refusing blood transfusion may be more concerned about the risks than the benefits. The clinician should present as balanced a discussion as possible. Benefits may be life-saving, patient stabilization, and/or symptomatic relief. Risks generally include infection, varying types of allergic transfusion reactions, graft versus host disease, volume overload, and electrolyte and clotting factor disturbances.

Therapeutic alternatives for patient unwilling to undergo transfusions include the following:

  • Using “blood substitutes” if available and permissible by patient
  • Reducing blood loss through minimizing the volume of blood used for laboratory testing
  • Reducing the oxygen requirement (eg, 100% oxygen, sedation, mechanical ventilation, control of body temperature, hyperbaric chamber)
  • Increasing the patient’s red cell production with autologous transfusion and/or erythropoietin (if acceptable) and supplemental iron and vitamins as needed

The idea that competent adults have the right to refuse medical treatment, including fluid resuscitation, is well established. Children are minors and therefore not capable of informed consent. The clinician’s duty is to seek legal intervention when a child is placed at "clear and substantial" risk by parental decisions. [12] In the event of a life-threatening clinical scenario that requires blood transfusion, a court order is not needed in order to transfuse a minor.

Next:

Monitoring & Follow-up

General parameters

Several diagnostic studies can aid in evaluation of a hypovolemic patient. Basic vital signs of hypotension and tachycardia are used to initially identify patient who are in need of volume resuscitation and can be followed to monitor their progress.

Arterial blood pressure

The first changes in arterial blood pressure that may indicate hypovolemia is a narrow pulse pressure, as previously mentioned. Orthostatic hypotension followed by hypotension regardless of position rapidly follow. Consider that while the normal blood pressure is considered 120/80 mmHg, hypovolemia may be indicated by a pressure above the normal range in a patient who is normally hypertensive. Additionally, arterial blood pressure does not adequately reflect cardiac output or regional hypoperfusion.

Central venous pressure

The venous circulation contains 70% of blood volume; therefore CVP response to fluid administration is useful for monitoring volume status. In general, if the CVP does not rise after infusion of a bolus of fluids, then the vascular system must still be very compliant, meaning that the “tank “ is not full. If a patient does not have intravenous monitoring, volume status may also be evaluated at the bedside by assessing jugular venous distension (JVD) or using ultrasound to visualize the IVC collapse in response to patient inspiration.

SvO2

Central venous oximetry is a useful parameter for monitoring the global oxygen supply-demand balance. SvO2 less than 70% indicates global hypoperfusion leading to increased tissue oxygen extraction in response to poor oxygen delivery. SvO2 is not sensitive to regional hypoperfusion such as splanchnic hypoperfusion.

Urine output

Oliguria or low urine output may be a sign of volume depletion since the kidney's response to hypovolemia is to resorb sodium and water. As urine output increases, it can be a useful proxy for adequate volume resuscitation. Note that urine output may differ for patients with impaired renal function but is usually 30 mL/hr as a minimum.

Physical examination

During fluid resuscitation, looking for signs of extravascular leak, such as pulmonary and interstitial edema, is important. Frequent physical examinations of the heart, lungs, JVD, and bowel sounds should be documented during the resuscitation process.

Ultrasound

Ultrasonography has been suggested as a useful noninvasive tool for the detection and monitoring of hypovolemia. Two possible sonographic markers for hypovolemia are the diameters of the inferior vena cava (and the right ventricle. In general, inferior vena cava size of less than 1.5 cm with total collapse on inspiration equates to a central venous pressure of 0-5, whereas a size greater than 2.5 cm with no collapse on inspiration equates to central venous pressure over 20. [13]

Children

Children have a tendency to decompensate quickly. Thus, close attention to vitals and signs of shock are extremely important. Capillary refill is largely affected by ambient temperature and is not a reliable sign of hypotension. A child with pallor has likely suffered profound blood loss. The best signs to monitor are tachycardia, which is the earliest sign of volume loss in children; blood pressure; and the quality of central and peripheral pluses. Remember that blood pressure in children is dependent on size and age. A general rule to follow is 70 + (2 times age in years) = systolic for children over 1 year old. Diastolic blood pressure is usually 2/3 systolic.

Previous