Hemodynamic Function during Neurectomy in Halothaneanesthetized Horses with or without Constant Dose Detomidine Infusion

Nine horses were premediated with acepromazine, and anesthesia was induced with guaifenesin and thiamylal. Anesthesia was maintained in four horses with halothane in oxygen, and in five horses with halothane in oxygen plus a constant dose infusion of detomidine. Both maintenance regimens produced a MAC equivalent of 1.4 at the ambient barometric pressure. Hemodynamic and respiratory measurements were made after the horses were anesthetized, during surgical manipulations involving skin or tissues other than nerves, during manipulation and transection of digital nerves, and after surgery while the limbs were being bandaged. Heart rate was significantly higher in horses anesthetized with halothane only than in horses that also received detomidine; there were no other differences in hemodynamic function or recovery characteristics. Respiratory rate was significantly higher than baseline during soft tissue and nerve manipulations; arterial blood pressure was significantly higher after surgery began and highest during neurectomy; cardiac output and cardiac index were significantly decreased during surgery; systemic vascular resistance was significantly increased during neurectomy and bandaging and highest during neurectomy. The data suggest that the increase in blood pressure often associated with surgical stimulation is caused by increased vascular resistance and may be accompanied by a decrease in cardiac output.     

Haemobartonella canis (Kiküth, 1928) in the blood of dogs with parvovirus disease

In the Tours area of the Val-de Loire, haemograms carried out in 40 dogs with canine parvovirus disease showed that in 30 cases the viral infection was complicated by canine haemobartonellosis. To the picture, typical of the former infection, were added very severe anaemia, fever, locomotor difficulties, arthralgia, adenopathy, respiratory difficulties (dyspnoea, polypnoea and anoxia) and circulatory disorders (tachycardia and capillary fragility). The blood picture was markedly abnormal, anisocytosis, poikilocytosis and anisochromia, being found together with alterations in the blood counts (neutrophils 85 to 90% high; leucocytes, 400 to 500 mm3; erythrocytes, 0·6 to 1·5 × 10⁶ mm³). Symptomatic treatment and serotherapy (equine hyperimmune serum against feline panleucopenia) were given for the parvovirus infection. Of the antimicrobial agents, only chloramphenicol, a spiramycin metronidazole association and sulphamethoxypyridazine gave good results. A high dose of intramuscular chlorpromazine (2 to 4 mg/kg b.w.) repeated 48 h later, followed by an 8-day course of oral treatment at a moderate dosage (1 mg/kg b.w. daily) produced complete clinical cure and disappearance of Haemobartonella canis from the peripheral blood. It is considered that these results support the view that an intercurrent infection may upset the balance existing between the host and parasite in carriers of H. canis and produce a virulent infection (see Fig. 1).