Читать книгу Complications in Equine Surgery - Группа авторов - Страница 34

Definition

Medical errors related to medications are numerous, including overdosing, underdosing, using the wrong medication, and using the wrong formulation. These will not be discussed here, but two types of medication errors will be highlighted. One is the wrong route of administration and the other is accidental injection of a non‐drug. One relatively common example of a wrong route error is the administration of procaine penicillin directly into the vascular system [26]. An example of administration of a non‐drug is the inadvertent intravenous administration of mare’s milk in a neonatal foal [27].

Risk factors

 Inexperience and inattentiveness are common reasons for medication errors.

 Repeated intramuscular injections may increase vascularity of the site and increase the risk of venous absorption of the administered drug.

Pathogenesis

Procaine penicillin must be administered by intramuscular or subcutaneous injection, because those routes limit the systemic absorption of procaine. Most commonly, procaine penicillin reactions occur when the drug is administered by the correct intramuscular route, but the injection inadvertently results in the intravenous absorption of a small amount of procaine [28]. Less commonly, but more significantly, an inexperienced or inattentive individual may directly inject procaine penicillin intravenously. This is most likely to occur when there is an indwelling intravenous catheter, because of the perceived convenience. Inadvertent intravenous administration of mare’s milk has occurred when the intravenous catheter injection port was confused with the nasogastric feeding tube port, resulting in an acute anaphylactic reaction.

Prevention

In general, further administration of procaine penicillin is discontinued after a procaine reaction occurs. Inadvertent, direct intravenous administration of procaine penicillin can be avoided by emphasizing that opaque medications should not be administered intravenously (notable exceptions of propofol and lipid emulsions in selected circumstances) [26]. Important safeguards to prevent confusion of intravenous and enteral access ports when multiple tubes and catheters are placed in patients are to color‐code enteral administration devices, labeling injections ports and enteral ports, and use of connections that are incompatible between enteral and intravenous ports [27]. Protocols to trace the tubing to the site of entry in the patient before injecting any medication are recommended but may be overlooked by inexperienced or inattentive individuals [27].

Diagnosis

Severity of procaine reactions vary with amount absorbed and individual variation [29]. Clinical signs range from hyper‐reactivity to seizures to death [26, 28, 29]. Inadvertent intravenous administration of milk was associated with acute signs of collapse and respiratory distress, consistent with anaphylaxis. Peripheral pulses were weak and mucous membranes were congested.

Treatment

Personnel should be moved away from the affected horse and the horse should be moved to a safe, quiet place (stall) and sedated, if possible [26]. External stimulation should be minimized by reducing light and sound. If seizure activity occurs, benzodiazepines and phenobarbital may be administered, if safe to do so [26]. The inadvertent administration of milk was treated by immediate removal of the contaminated intravenous catheter and aggressive supportive therapy, including epinephrine, corticosteroids, intravenous fluids, antimicrobial therapy, and inotropic support.

Expected outcome

Horses typically recover from procaine reactions, but fatal reactions can occur. More commonly, self‐trauma may result from the hyper‐excitability and seizures. The foal with inadvertent intravenous administration of milk did recover with aggressive treatment and no long‐term consequences were noted.