Effects of mephentermine and norepinephrine administration following thiopentone induced circulatory insufficiency in buffalo calves (Bubalus bubalis)

The study was undertaken to evaluate the effects of mephentermine and norepinephrine following thiopentone induced circulatory insufficiency in buffalo calves. Fifteen buffalo calves were equally divided in three groups. In all the three groups, circulatory insufficiency was induced with thiopentone sodium, and in group I animals no treatment was given. In other groups, efficacies of mephentermine (group II) and norepinephrine (group III) were evaluated. Electrical activity in the EEG was noticed 2.47±0.32 min after mephentermine administration. The heart rate and mean arterial pressure (MAP) were significantly elevated 5 min after mephentermine administration. The elevated CVP recorded during circulatory insufficiency fell below the base value following mephentermine administration. Arterial O₂ tension remained elevated, while venous O₂ and arterial CO₂ tension remained within normal limits. Moderately elevated blood glucose levels during circulatory insufficiency were further elevated by mephentermine administration. Electrical activity in the EEG returned within 1.63±0.18 min after the start of norepinephrine drip. Arterial pressure was lowered by 5 min. The elevated CVP recorded during circulatory insufficiency also decreased after 15 min of norepinephrine drip. The results indicated that both drugs are effective in counteracting circulatory insufficiency, but mephentermine appears better of the two.