Analgesic monitoring in experimental animals

• Autor(a) principal: Leitão, Carlos Jorge de Sá
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10348/8513

Background. Evaluation of nociceptive-anti-nociceptive balance during general anesthesia is still challenging and routinely based on clinical criteria. Analgesics drugs delivered may be optimized with PTA (Parasympathetic tone activity) monitoring. Objective. To compare ketorolac and ketorolac-tramadol combination analgesia balance during the nociceptive stimulation using a PTA monitor. Animals: Twenty seven Large White healthy pigs weighing 49±5kg [mean ± standard deviation (SD)] aged between eighty-five and ninety days. Methods. Animals were divided in Without Analgesia (WA), Ketorolac (K) and Ketorolac/Tramadol (K/T) groups. The study lasted twenty minutes and the stimulus was applied in the apex of left ear, at ten minutes. Pain intensity response was assessed using a 0-100 numerical state scale (PTA), after one nociceptive stimulus under stable anaesthesia. A high PTA value corresponds to absence of nociception and a low value to inadequate analgesia. Bispectral index, heart rate, non-invasive blood pressure and respiratory parameters were also measured. Mean areas under the curve were compared between groups through one-way mixed-model repeated measures ANOVA and Kruskal-Wallis tests. Results. After application of the stimulus, it was observed a significant decrease from 70 for 40.3 in the mean PTA value for WA group. In K group the mean PTA values decreased from 75.2 to 54.4 after stimulus. The K/T group showed the highest PTA values with 87.6 before and 86 after stimulus. Heart rate showed a slight increase of mean values in WA group from 92.6 to 99.8 Bpm. Bispectral index and Non-invasive blood pressure means showed no statistically significant differences either over time or between different treatments groups. Conclusion and Clinical Relevance. This study shows that a low dose combination of Ketorolac and Tramadol is sufficient to block the pain responses twenty minutes after its administration and also shows that PTA monitor was able to clear recognize the analgesic level between treatments and may be used to optimize analgesic drug delivered.