Different fasting periods in tiletamine-zolezepam-anethetized cats: Glycemia, recovery, blood-gas and cardiorrespiratory parameters

The effects of different fasting periods on glycemia levels and on cardiorrespiratory parameters in tiletamine-zolazepam-anesthetized cats were evaluated. Twenty one animals were randomly assigned to three groups: 8 hours (G8), 12 hours (G12) or 18 hours (G18) of the preoperative fasting. The tiletamine-zolazepam (2 mg/kg) was administered intravenously. The heart rate (HR), respiratory rate (fR), rectal temperature (T R), glycemia (G), laboratorial glycemia (Glab), venous oxygen partial pressure (PvO2), venous carbon dioxide partial pressure (PvCO2), venous hemoglobin saturation (SvO2), pH, base deficit (BD), bicarbonate concentration (HCO3- ) and haematocrit were evaluated at 90 minutes after the last meal (T0), immediately before anesthesia (T1) and at ten (T2) and thirty (T3) minutes after tiletamine-zolezepam administration. The time between the administration of anesthetic and the cat's trial to elevate head (Th) and the interval between drug administration and aniamal's quadrupedal position (Tqp) were recorded. No differences among groups were recorded for glycemia, HR, PvO2, SvO2, pH, BD, HCO3-, Ht and Tqp. In G12 from T2, glycemia increased and from T1 PvCO2 decreased. At T1, PvO2 increased in all groups. In G8 and G12, from T1, DB and HCO3- decreased. In G12 and G18, from T2, Ht decreased. In G12, the Th mean was higher than G8. In conclusion, in tiletamine-zolazepam-anesthetized cats, the different preoperative fasting did not influence glycemia, blood-gas and cardiorrespiratory parameters. Additionally, there was no relationship between glycemia and anesthesia recovery

Evaluation of the cardiopulmonary and antinociceptive effects of bupivacaine administered epidurally at the first lumbar vertebra in awake dogs

ABSTRACT The aim of this study was to evaluate the effect of epidural bupivacaine administration at the first lumbar vertebra on cardiopulmonary variables, arterial blood gases and anti-nociception. Sixteen healthy female dogs were randomly assigned into two groups based on bupivacaine dose: G1 group, 1mg kg-1 or G2 group, 2mg kg-1, diluted in the same final volume (1mL4kg-1). Cardiopulmonary variables were measured and arterial blood gas was collected (T0), it was repeated 10 minutes after intravenous administration of butorphanol 0.4mg kg -1 (T1). Anesthesia was induced with intravenous etomidate at 2mg kg-1 and the epidural catheter was introduced and placed at the first lumbar vertebra. Thirty minutes later, bupivacaine was administered epidurally. Cardiopulmonary measurements and arterial blood gas analysis were recorded at 10 minute intervals (T2 to T6). Evaluation of pre surgical anti-nociception was performed at 5 minute intervals for 30 minutes by clamping the hind limbs, anus, vulva, and tail with the dogs awake. Subsequently, ovariohysterectomy was performed and adequacy of surgical anti-nociception was evaluated at 5 time points. Parametric data were analyzed using the F test with a <0.05 significance. After bupivacaine administration, there were differences between groups just for bicarbonate means (HCO3 -) on T6 (P=0.0198), with 18.7±1.3 and 20.4±0.8 for G1 and G2, respectively. After T1, before bupivacaine administration, both groups presented a slightly lower pH, base excess (BE), the end-tidal carbon dioxide tension (PECO2), and partial pressure of carbon dioxide (PaCO2), suggesting mild metabolic acidosis. G2 showed better antinociceptive effect both before and during surgery. It was possible to perform ovariohysterectomy in 87.5% of the G2 bitches and 25% of the G1 bitches. The two doses of bupivacaine evaluated do not cause important alterations in the studied parameters and the dose of 2mg kg-1 results in a better antinociceptive effect

Avaliação de parâmetros cardiovasculares, ventilatórios e hemogasométricos de coelhos anestesiados com isofluorano ou sevofluorano e submetidos à ventilação espontânea ou controlada a volume

The volume-controlled mechanical ventilation and spontaneous ventilation, through haemogasometric, cardiovascular and spirometry variables were evaluated. Twenty-eight rabbits were distributed into two groups: GIVC (isoflurane and volume-controlled ventilation), GIVE (isoflurane and spontaneous ventilation), GSVC (sevoflurane and volume-controlled ventilation) and GSVE (sevoflurane and spontaneous ventilation). Induction was performed by mask with isoflurane (GIVE and GIVC) or sevoflurane (GSVE and GSVC) at 1.5 MAC in 100% oxygen. To maintain anesthesia, MAC was reset to 1. In GIVC and GSVC groups, rocuronium was administered at a dose of 0.6 mg/kg followed by its continuous infusion (0.6 mg/kg/h). In GSVE and GIVE, 0.9% NaCl was administered instead of rocuronium. Controlled ventilation was started by adjusting the capnometry in order to obtain values between 35 and 45 mmHg. Parameters were measured 60 minutes after induction of anesthesia (M0), 15 minutes after the bolus of rocuronium or 0.9% NaCl (M15) and every fifteen minutes (M30, M45 and M60). Hypercapnia and acidosis was evident in GIVC, GSVC and GSVE. We concluded that the volume-controlled mechanical ventilation was not able to maintain normocapnia in rabbits, producing acidosis in them, especially when using sevoflurane. The use of isoflurane showed greater stability than the sevoflurane anesthetic in the species studied.Avaliaram-se as ventilações mecânica controlada a volume e espontânea, por meio das variáveis hemogasométricas, cardiovasculares e ventilométricas. Distribuíram-se 28 coelhos nos grupos: GIVC (isofluorano e ventilação controlada a volume), GIVE (isofluorano e ventilação espontânea), GSVC (sevofluorano e ventilação controlada a volume) e GSVE (sevofluorano e ventilação espontânea). Induziu-se por máscara, com isofluorano (GIVE e GIVC) ou sevofluorano (GSVE e GSVC) a 1,5 CAM, em oxigênio a 100%. Para manutenção anestésica, reajustou-se para 1 CAM. No GIVC e no GSVC, administrou-se rocurônio, na dose de 0,6mg/kg, seguida de infusão contínua na mesma dose de 0,6mg/kg/h. No GIVE e no GSVE, foi administrado NaCl 0,9% em vez de rocurônio. Iniciou-se a ventilação controlada ajustando-a de maneira a obter capnometria entre 35 e 45mmHg. Mensuraram-se os parâmetros 60 minutos após a indução anestésica (M0), 15 minutos após o bolus de rocurônio ou NaCl 0,9% (M15) e a cada 15 minutos (M30, M45 e M60). Evidenciou-se hipercapnia e acidose em GIVC, GSVC e GSVE. Concluiu-se que a ventilação mecânica controlada a volume não foi capaz de manter a normocapnia em coelhos, gerando acidose, principalmente quando se utilizou sevofluorano. O uso do isofluorano demonstrou maior estabilidade anestésica que o sevofluorano nesta