RESUMO
Large arachnids are commonly managed under professional care, and anesthesia is occasionally required for physical examination and diagnostic and therapeutic procedures. Anesthetic responses and hemolymph gas analysis have been studied previously in spiders, but scorpions have yet to be investigated. This study measured hemolymph gas values with an i-STAT point of care blood gas analyzer in healthy adult Asian forest scorpions (Heterometrus longimanus = HL, n = 8) and dictator scorpions (Pandinus dictator = PD, n = 12) breathing: 1) room air (RA), 2) 100% oxygen for 10 min in a chamber (OX), and 3) 5% isoflurane and oxygen (ISO) in a chamber until induction or loss of righting reflex. All scorpions recovered without complications, and there were no cartridge failures. Analysis of hemolymph gas values revealed that pH was lower in OX compared with RA and ISO and was lower in PD compared with HL scorpions. The partial pressure of carbon dioxide did not differ between inhaled gases but was higher in PD compared with HL. The partial pressure of oxygen (pO2) was higher in ISO compared with OX, and both were higher than when breathing RA. Despite a lack of species difference in pO2, PD had a more dramatic increase in pO2 in ISO compared with HL (significant species and inhalant interaction). PD had a significantly shorter induction time than HL, but recovery time (return of righting reflex) did not differ between species. Subjectively, HL exhibited rough inductions compared with PD, characterized by violent whole-body and tail movements. The unexpected increase in pO2 in ISO compared with OX, along with the species-specific differences and anesthetic effects, emphasizes the unique respiratory physiology of scorpions and demonstrates that further species-specific studies of anesthetics are warranted.
