Idiosyncrasies in greyhounds that can affect anaesthesia
Delayed Post-operative Bleeding
Delayed postoperative bleeding occurring in approximately 26% - 30% of greyhounds. As suggested, bleeding is delayed, often occurring 36 - 48hr after a procedure or trauma incident. Delayed bleeding often manifests as cutaneous bleeding or hemorrhage from and/or around the surgical site.
In affected greyhounds, common haemostasis assays are often normal, suggesting that bleeding is unrelated to primary or secondary abnormalities.
Primary haemostatic abnormalities characterised by bleeding from mucosal surfaces (eg.haematuria, epistaxis), petechiae and prolonged bleeding from cuts or venipuncture. Secondary haemostatic abnormalities are characterised by more severe bleeding into, e.g.joints and body cavities, haematomas, ecchymoses and delayed bleeding from cuts.
Studies suggest the delayed bleeding is related to enhanced fibrinolysis (the enzymatic break down of the fibrin in blood clots.) or weaker clot strength.As a result, administering an antifibrinolytic pre-, peri- and postoperatively is recommended to reduce the frequency and severity of the bleeding.
Note: administration of NSAIDs is unlikely to contribute to the delay
Tranexamic acid (TXA) is a man-made form of an amino acid (protein) that prevents enzymes in the body from breaking down blood clots.
TXA also comes in capsule forms, and is given Pre-operatively and three times daily for five to seven days postoperatively.
Hyperkalaemia in dogs (defined as serum potassium >5.5 mmol/L) is a serious electrolyte disturbance that can pose a risk to life if untreated. Maintenance of high intracellular and low extracellular potassium levels are necessary for cellular functions and cell membrane electrical gradient stability. The development of unanticipated hyperkalaemia during anaesthesia has been increasingly reported in dogs, with higher prevalence in greyhounds over recent years, with consequences ranging from brady-dysrhythmias to cardiac arrest.
While the aetiology is unclear at this time, in some cases there are a couple of changes in vitals to be aware of while monitoring GA, that can potentially indicate an increase in potassium levels.
• Acute bradycardia over an hour after induction of anaesthesia
• Changes in the ECG waveforms
Monitoring potassium level
Electrolyte profiles performed pre- and perioperavtively (at every 1hr post induction) to evaluate and monitor increases in serum potassium concentration.