11. Anesthesia related mortality in different species (also possible reasons and prevention)

Question 1

11. Anesthesia related mortality in different species (also possible reasons and prevention)

Answer 1

ASA categories
I -apparently healthy
>ovariohysterectomy, mild
periodontal disease, patellar luxation
II-mild systemic disease
>neonatal or geriatric animals,
compensated cardiac disease, small tumors
III-severe systemic disease >chronic cardiac disease, fever, dehydration, cachexia, anemia
IV-severe systemic disease that is life threatening
>heart failure, renal failure, hepatic failure, severe hypovolemia, severe
hemorrhage
V-moribund; patient not expected to live longer than 24 hours without
surgery
>endotoxic shock, multiorgan failure, severe trauma

Anesthesia-related mortality (2002-04, UK)
-dogs (n=98036):
*0,17% (1:600)
*ASA I-II: 0,05% (1:1800)
*ASA III-IV: 1,3%
>timing of death
*after pre-medication 1%
*induction 6%
*maintenance 46%
*postoperative period 47%
-cats (n=79178):
*0,24% (1:400)
*ASA I-II: 0,11% (1:900)
*ASA III-IV: 1,4%
>timing of death
*after pre-medication 1%
*induction 8%
*maintenance 30%
*postoperative period 61%

Anesthesia-related mortality
°risk ~2 times higher for cats in comparison to dogs
°possible reasons:
>smaller animal(hypothermia, overhydrating)
>uncooperative behaviour
>prone to laryngospasm
>sensitivity to local anesthesia drug toxicity
>reduced glucuronidation (slower drug metabolism)

Anesthesia-related mortality
*data from different studies variable
*rabbits: 1:70
>most other small animal species have higher mortality risks
*horses: 1:100
*humans: 1:100000
*older studies show
higher death rates

Anesthesia-related mortality in dogs(2010-13,UK)
*157318 dogs
*159 deaths in 48 hours (0.1%)
*219 deaths in two weeks (0.14%)
*ovariohysterectomy/orchidectomy (8/89852 – 0.009%)
*ASA III – risk 4,8x greater
*ASA IV-V – risk 19x greater
*ASA E (emergency) – risk 13,6x greater

Postoperative period-highest risk