The aim of this PhD study, which was carried out in the Istanbul University Surgery Departmet, has been the early diagnosis and treatment of rhythm disorders occurring in every step of the general anaesthesia procedure and" in the intra-operative period using continuous ECG monitoring in dogs undergoing surgery due to various surgical diseases.
In the study, in which 75 clinical cases were evaluated, different anaesthesia protocols were determined according to criteria such as duration and character of surgery, risk of anaesthesia in the patient and general condition of the patient.
In 55 dogs which were administered with xylazine for sedation during premedication, rhythm disorders such as bradycardia, atrial standstill and 1st degree AV block were encountered in 26. Atropine was used for the treatment of these rhythm disorders. Following administration of the drug. 1st or 2nd degree heart block occurred temporarily; however, heart rate and rhythm returned to normal after a while.
In dogs which were given diazepam for tranquilisation, it was observed that the pre-anaesthesia heart rhythm in the ECG readings remained stable.
In 53 of a total of 59 cases, to which ketamine was administered for anaesthesia induction, it was seen that with respect to initial values, heart rate increased; however, the heart rhythm remained the same. It was observed that the Is1 degree AV block seen in 3 eases and occurring due to atropine administration, disappeared during inhalation anaesthesia. In 2 of 3 cases in which sinus tachycardia was detected, it was seen that the heart rate dropped to within normal limits following verapamil administration. The remaining case, which had a tolerable heart rate, rhythm returned to normal during halothane anaesthesia.
There was no change cither in heart rate or in rhythm in cases which were given etomidate as an induction agent.
Of 51 cases, in which halothane was given for the continuation of inhalation anaesthesia, it was seen that heart rhythm did not change in 48 cases and 1st degree AV block occurred in the remaining 3. This form of arrhythmia was not treated as it was within normal limits.
Two cases, in which 2nd degree AV block occurred in the ECC readings taken after halothane anaesthesia, were given atropine. Following administration, atrial standstill occurred in 1 case and 2nd degree AV block together with 1st degree AV block occurred in the other case. However, these rhythm disorders were temporary.
While atrioventricular junctional rhythm occurred in only I of the dogs to which isoflurane was administered as the inhalation anaesthetic, no change was seen in the other cases. Atrioventricular junctional rhythm returned to normal spontaneously. Following isoflurane anaesthesia, heart rhythm disorders were not encountered in any of the cases.
Finally, in view of our findings; it has been concluded that diazepam is more reliable than xylazine for tranquilisation, etomidale is more reliable than ketamine for induction and isoflurane is more reliable than halothane during inhalation anaesthesia with respect to the incidence of cardiac arrhythmias.