Effect of Acetaminophen Alone and in Combination with Morphine and Tramadol on the Minimum Alveolar Concentration of Isoflurane in Rats.

BackgroundIt has been observed that acetaminophen potentiates the analgesic effect of morphine and tramadol in postoperative pain management. Its capacity as an analgesic drug or in combinations thereof to reduce the minimum alveolar concentration (MAC) of inhalational anesthetics represents an objective measure of this effect during general anesthesia. In this study, the effect of acetaminophen with and without morphine or tramadol was evaluated on the isoflurane MAC.MethodsForty-eight male Wistar rats were anesthetized with isoflurane in oxygen. MACISO was determined from alveolar gas samples at the time of tail clamping without the drug, after administering acetaminophen (300 mg/kg), morphine (3 mg/kg), tramadol (10 mg/kg), acetaminophen (300 mg/kg) + morphine (3 mg/kg), and acetaminophen (300 mg/kg) + tramadol (10 mg/kg).ResultsThe control and acetaminophen groups did not present statistically significant differences (p = 0.98). The values determined for MACISO after treatment with acetaminophen + morphine, acetaminophen + tramadol, morphine, and tramadol were 0.98% ± 0.04%, 0.99% ± 0.009%, 0.97% ± 0.02%, and 0.99% ± 0.01%, respectively.ConclusionsThe administration of acetaminophen did not reduce the MAC of isoflurane and did not potentiate the reduction in MACISO by morphine and tramadol in rats, and therefore does not present a sparing effect of morphine or tramadol in rats anesthetized with isoflurane

Lidocaine, dexmedetomidine and their combination reduce isoflurane minimum alveolar concentration in dogs.

The effects of intravenous (i.v.) lidocaine, dexmedetomidine and their combination delivered as a bolus followed by a constant rate infusion (CRI) on the minimum alveolar concentration of isoflurane (MACISO) in dogs were evaluated. Seven healthy adult dogs were included. Anaesthesia was induced with propofol and maintained with isoflurane. For each dog, baseline MAC (MACISO/BASAL) was determined after a 90-minute equilibration period. Thereafter, each dog received one of the following treatments (loading dose, CRI): lidocaine 2 mg kg(-1), 100 µg kg(-1) minute(-1); dexmedetomidine 2 µg kg(-1), 2 µg kg(-1) hour(-1); or their combination. MAC was then determined again after 45- minutes of treatment by CRI. At the doses administered, lidocaine, dexmedetomidine and their combination significantly reduced MACISO by 27.3% (range: 12.5-39.2%), 43.4% (33.3-53.3%) and 60.9% (46.1-78.1%), respectively, when compared to MACISO/BASAL. The combination resulted in a greater MACISO reduction than the two drugs alone. Their use, at the doses studied, provides a clinically important reduction in the concentration of ISO during anaesthesia in dogs

Lidocaine, dexmedetomidine and their combination reduce isoflurane minimum alveolar concentration in dogs.

The effects of intravenous (i.v.) lidocaine, dexmedetomidine and their combination delivered as a bolus followed by a constant rate infusion (CRI) on the minimum alveolar concentration of isoflurane (MACISO) in dogs were evaluated. Seven healthy adult dogs were included. Anaesthesia was induced with propofol and maintained with isoflurane. For each dog, baseline MAC (MACISO/BASAL) was determined after a 90-minute equilibration period. Thereafter, each dog received one of the following treatments (loading dose, CRI): lidocaine 2 mg kg(-1), 100 µg kg(-1) minute(-1); dexmedetomidine 2 µg kg(-1), 2 µg kg(-1) hour(-1); or their combination. MAC was then determined again after 45- minutes of treatment by CRI. At the doses administered, lidocaine, dexmedetomidine and their combination significantly reduced MACISO by 27.3% (range: 12.5-39.2%), 43.4% (33.3-53.3%) and 60.9% (46.1-78.1%), respectively, when compared to MACISO/BASAL. The combination resulted in a greater MACISO reduction than the two drugs alone. Their use, at the doses studied, provides a clinically important reduction in the concentration of ISO during anaesthesia in dogs

Blood gas, bicarbonate and lactate values obtained when determining the MAC in the different treatment groups.

<p>Blood gas, bicarbonate and lactate values obtained when determining the MAC in the different treatment groups.</p

Mean ± SD of minimum alveolar concentration of isoflurane (MAC_ISO) before (MAC_ISO/BASAL) and after one of the following treatments (MAC_ISO/T): lidocaine (LIDO), dexmedetomidine (DEX), or the combination LIDO-DEX in dogs (<i>n</i> = 7).

<p>The percentage (%) change in MAC_ISO after treatment was calculated from [(MAC_ISO after treatment – MAC_ISO/BASAL)/MAC_ISO/BASAL] X 100.</p><p>*Statistically different from MAC_ISO/BASAL (<i>p</i><0.05).</p>#<p>Statistically different from the rest of the treatments (<i>p</i><0.05).</p><p>Mean ± SD of minimum alveolar concentration of isoflurane (MAC_ISO) before (MAC_ISO/BASAL) and after one of the following treatments (MAC_ISO/T): lidocaine (LIDO), dexmedetomidine (DEX), or the combination LIDO-DEX in dogs (<i>n</i> = 7).</p

Demonstrating the presence of Ehrlichia canis DNA from different tissues of dogs with suspected subclinical ehrlichiosis

Background: Nowadays, Ehrlichia canis receives increasing attention because of its great morbidity and mortality in animals. Dogs in the subclinical and chronic phases can be asymptomatic, and serological tests show cross‑reactivity and fail to differentiate between current and past infections. Moreover, there could be low parasitaemia, and E. canis might be found only in target organs, hence causing results to be negative by polymerase chain reaction (PCR) on blood samples.Methods: We evaluated by PCR the prevalence of E. canis in blood, liver, spleen, lymph node and bone marrow sam‑ples of 59 recently euthanised dogs that had ticks but were clinically healthy.Results: In total, 52.55% of the blood PCRs for E. canis were negative, yet 61.30% yielded positive results from tissue biopsies and were as follows: 63.15% from bone marrow; 52.63% from liver; 47.36% from spleen; and 15.78% from lymph node. In addition, 33% had infection in three tissues (spleen, liver and bone marrow).Conclusions: Our results show the prevalence of E. canis from tissues of dogs that were negative by blood PCR. Ehrli-chia canis DNA in tissue was 30% lower in dogs that tested negative in PCR of blood samples compared to those that were positive. However, it must be taken into account that some dogs with negative results were positive for E. canis in other tissues.Keywords: Ehrlichia canis, Biopsies, Spleen, Bone marrow, Liver, Lymph nod

Mean ± SD of cardiovascular parameters and other variables measured immediately before the MAC determination of isoflurane (MAC_ISO/BASAL) and immediately before the final MAC of isoflurane (MAC_ISO/T) determination during constant rate infusion of lidocaine (LIDO), dexmedetomidine (DEX), or the combination LIDO-DEX.

#<p>Statistically different to baseline and to the rest of the treatments (<i>p</i><0.05).</p><p>Mean ± SD of cardiovascular parameters and other variables measured immediately before the MAC determination of isoflurane (MAC_ISO/BASAL) and immediately before the final MAC of isoflurane (MAC_ISO/T) determination during constant rate infusion of lidocaine (LIDO), dexmedetomidine (DEX), or the combination LIDO-DEX.</p