Feb 27, 2013 I spayed a Maltese X., 4.3 kg
Based on formula of 10 kg, young healthy dog Dom=0.4 and Ket=0.5, I gave this 4.3 kg dog IV Dom=0.2 + Ket = 0.17 totalling 0.37 ml IV one syringe with 0.13 ml Hartmann.
A: Injection of D+K IV 10.22 am
B: Isoflurane first given 10.43 am
C: Isoflurane stopped 10.53 am
D: First skin incision: 10.34 am
E: Completion of skin stitching: 11.01 am.
E-A = 39 minutes. This is because the dog started moving at 10.43 am (21 minutes after injecton)and the surgery was paused to give gas by mask to stabilise. This shows that duration of D + K is 21 minutes for this dog. Spay should be completed in 21 minutes but there was some delay as there was training of the new veterinary staff on gas anaesthesia. Without traiining, spay should be completed in 30 minutes for this small breed.
E-D= 27 minutes. Dog was on heat. More time was spent ensuring no bleeding and on speed on hooking out the ovaries.
Hooking left ovary took 3 trials and it was hooked out at 10.38 am. 4 minutes after incision. Right ovary was hooked out at 10.42 am, 8 minutes after skin incision.
Conclusion: Usually the above formula gives at least 20 minutes of surgical anaesthesia. If spay takes longer, isoflurane top up is needed. Efficiency and timing are important in productivity of a vet surgeon. Taking too long to spay a dog is not good.