Preoperative Considerations: Key Terms for Premedication and Fluid Therapy

35 vocabulary-style flashcards covering preoperative assessment, physical status classifications, IV access, fluids (crystalloids and colloids), and related clinical concepts from the notes.

Preanesthetic care

Process of correcting identifiable problems (e.g., dehydration, shock, hypothermia) before surgery when time allows.

IV catheter size (dog)

Typically 18–20 gauge; 22 gauge for small dogs; adapt size as needed.

IV catheter size (cat)

Typically 20–22 gauge; 24 gauge for kittens; adjust as needed.

Crystalloids

Water-based IV fluids with small solutes; move across capillary membranes; used for hydration and maintenance (e.g., LR, normal saline, Normosol, Plasmalyte).

Lactated Ringers (LR)

Balanced crystalloid containing lactate; used for volume replacement and hydration.

Normal saline 0.9% (NaCl)

Isotonic crystalloid commonly used for fluid therapy.

Normosol/Plasmalyte

Balanced crystalloid solutions used as alternatives to LR.

Hypotonic crystalloid

Fluid with lower osmolality (e.g., 0.45% NaCl); shifts fluid into cells.

Hypertonic saline

(5% NaCl); draws fluid into vessels; used in specific cases to support circulation.

Dextrose solutions (D5W)

used for hypoglycemia, caloric support, neonates; can be hypotonic.

Colloids

Non–water-based IV fluids with large molecules that stay intravascularly to expand volume (e.g., dextran, hetastarch, plasma, whole blood).

Dextran

Polysaccharide derived from glucose used as a plasma volume expander.

Hetastarch

Plant-derived starch (amylopectin) used as a synthetic colloid for volume expansion.

Plasma

Liquid portion of blood containing coagulation factors and proteins; used for volume expansion and coagulation support.

Whole blood

containing red cells, plasma, platelets; used to replace volume and improve oxygen-carrying capacity.

Oxyglobin

Chemically modified bovine hemoglobin; oxygen-carrying plasma substitute; does not require cross-matching.

Osmotic principle: crystalloids vs colloids

Crystalloids diffuse across capillaries; colloids stay intravascular, drawing water into vessels and maintaining volume.

Preanesthetic diagnostic tests

Labs and tests used to assess status: PCV, total solids, glucose, BUN; CBC/Chem/UA; ECG; blood gases; clotting times; radiographs as needed.

Species-specific anesthesia considerations

Different species have unique responses to anesthetics (e.g., horses/cats sensitive to opioids; brachycephalics can be difficult to intubate).

Preoperative communication with owner

Clear instructions and planning communicated to the owner before anesthesia.

Preanesthetic physical assessment plan

Comprehensive preop exam focusing on cardiovascular and pulmonary status and pain assessment.

Brachycephalic airway considerations

Breeds with shortened skulls may present airway challenges requiring adaptation during anesthesia.

IV catheter care and maintenance

aseptic handling, regular flushing, and monitoring for signs of infection or obstruction.