Effects of morphine-alfaxalone-midazolam premedication, alfaxalone induction and sevoflurane maintenance on intraocular pressure and tear production in dogs.

Intraocular pressure (IOP) and tear production are commonly affected by general anaesthesia. It is necessary to have a good control of both to guarantee successful ophthalmic surgery. The purpose of this research was to evaluate if the protocol based on the administration of morphine-alfaxalone-midazolam as premedication, alfaxalone as induction and sevoflurane as maintenance, can induce changes on IOP and Schirmer's tear test (STT-1) in healthy dogs. Twenty-two adult mixed-breed dogs scheduled for an ovariohysterectomy were enrolled for the study. IOP and STT-1 were registered at baseline (T0), 5 minutes (T1), 10 minutes (T2) and 15 minutes (T3) after premedication with a morphine-alfaxalone-midazolam combination; 5 minutes (T4) after induction with alfaxalone and 15 minutes (T5) and 25 minutes (T6) after maintenance with sevoflurane. A one-way analysis of variance was performed to analyse the difference between IOP and STT-1 over time, respectively. The present study shows a slightly statistically significant increase in IOP (P<0.05) after premedication, induction and maintenance that can be associated with this anaesthetic protocol. STT-1 showed a statistically significant reduction during all the procedures (P<0.001). These results should be taken into consideration, especially in dogs with damaged corneas, in those predisposed to glaucoma and in those due to undergo intraocular surgery. Ocular lubrication is necessary if this protocol is used.

Spectral transmission of the pig lens: effect of ultraviolet A+B radiation.

OBJECTIVE: To determine the spectral transmission curve of the crystalline lens of the pig. To analyse how this curve changes when the crystalline lens is irradiated with ultraviolet A+B radiation similar to that of the sun. To compare these results with literature data from the human crystalline lens. PROCEDURES: We used crystalline lenses of the common pig from a slaughterhouse, i.e. genetically similar pigs, fed with the same diet, and slaughtered at six months old. Spectral transmission was measured with a Perkin-Elmer Lambda 35 UV/VIS spectrometer. The lenses were irradiated using an Asahi Spectra Lax-C100 ultraviolet source, which made it possible to select the spectral emission band as well as the intensity and exposure time. RESULTS: The pig lens transmits all the visible spectrum (95%) and lets part of the ultraviolet A through (15%). Exposure to acute UV (A+B) irradiation causes a decrease in its transmission as the intensity or exposure time increases: this decrease is considerable in the UV region. CONCLUSIONS: We were able to determine the mean spectral transmission curve of the pig lens. It appears to be similar to that of the human lens in the visible spectrum, but different in the ultraviolet. Pig lens transmission is reduced by UV (A+B) irradiation and its transmission in the UV region can even disappear as the intensity or exposure time increases. An adequate exposure intensity and time of UV (A+B) radiation always causes an anterior subcapsular cataract (ASC).

Ocular biometry in the adult anesthetized ferret (Mustela putorius furo).

A total of 44 eyes of 22 ferrets were examined by B-mode ultrasonography. Four dimensions were measured: the distance from the corneal surface to the anterior lens surface (M1), the axial lens thickness (M2), the distance from the posterior lens surface to the retina (M3) and the distance from the anterior cornea to the retina (M4). The values obtained were (mean, standard deviation, range): M1: 1.31 +/- 0.16 mm (1-1.7); M2: 3.42 +/- 0.15 mm (3.2-3.7); M3: 2.26 +/- 0.11 mm (2.1-2.5); M4: 7 +/- 0.24 mm (6.4-7.7). To our knowledge this is the first description of ocular biometric measurement in the ferret. These values show little variability of ocular dimensions in ferrets.

The normal electrocardiogram of the unanaesthetized competition "Spanish Pouler" pigeon (Columba livia gutturosa).

This investigation was carried out on 64 healthy adult competition pigeons (Spanish Poulers) to determine reference values of electrocardiographic parameters in standard lead II; a comparative study between males and females was also performed to find changes in the electrocardiographic patterns related to sex. P wave was positive and monophasic; PR segment depression was present in 64% of records; the QRS pattern obtained was in most cases of the rS type, followed by the QS configuration. ST slurring (absence of ST) was observed in 47% of records and the mean electrical axis was in all cases negative. Statistically significant differences related to sex were found for P-wave, R-wave and T-wave amplitudes, showing the males have greater amplitudes than females, associated with the increase of cardiac tissue mass. No sex-related differences were found in heart rate and mean electrical axis.