Results And Discussion

Anaesthesia and monitoring data

Ketamine HCl was used without any additional sedative drugs on 44 occasions (mean 5.7 mg kg-1; range 4.1-8.8 mg kg-1; mean time to induction 10.3 minutes; range 1-58 minutes). The total procedure length averaged 43 minutes (range 28-144 minutes) with a total accumulated ketamine dose averaging 9.1 mg kg-1 (range 4.2-16.7 mg kg-1). In the remainder, ketamine was the primary agent but chlorpromazine, xylazine or diazepam was also used (see p. 60-61). In general, relaxation was poor with ketamine HCl alone, with no noticeable improvement with the additional injectable sedatives at the described dosages. Regardless, all animals were adequately immobilised for transport from the animal's home enclosure to the examination area to begin the procedure. Overall induction time averaged about 10 minutes with the total dosage used averaging about 1.5 times the initial dose. In most cases, oral examination and tattooing were difficult due to poor jaw relaxation and spontaneous head movement, often requiring ketamine HCl supplements of 50-100 milligrams (i.v. or i.m.) per animal or the administration of isoflurane. Despite this, virtually all individuals remained in a light plane of anaesthesia throughout the procedure, with some animals attempting to roll over or stand by the end of the examination. In contrast to other bears, the giant panda in this light anaesthetic plane rarely appeared dangerous to personnel.

Of the 67 anaesthetic episodes, there were no serious events during examination or recovery, although two individuals retched or vomited during induction or near the onset of recovery. Both of these animals had inadvertently received food a few hours before being anaesthetized. Of particular interest was the lack of untoward effects with ketamine HCl alone in the giant panda in contrast to more severe impacts in other carnivores, such as severe muscle rigidity and seizures (Ilkiw, 2002). Only one animal had seizure activity, which lasted less than 1 minute. For this reason, we concluded that ketamine HCl was a safe and effective anaesthetic choice for short, non-invasive procedures such as those used in the Biomedical Survey. Because of its high margin of safety, we suspect that, for all ages, a more rapid and smoother induction with less need for supplementation could be achieved by increasing the initial ketamine HCl dosage to 8-10 mg kg-1.

The various small, portable devices described in the 'Methods for medical evaluations' (from p. 65) were effective for monitoring multiple physiological parameters. This enabled closely tracking the plane of anaesthesia while collecting relevant data to evaluate the efficacy of the anaesthetic regimen. Virtually all pandas responded similarly and predictably to the ketamine HCl. The average systolic blood pressure was 155 mmHg (individual value range 86-237 mmHg with an average of eight measures per individual). Higher systolic pressures tended to occur in the larger adult males and were often sustained throughout the anaesthetic interval. For example, mean systolic pressure was higher (p < 0.05) in adult males (175 mmHg) compared to juveniles and adult females (157 and 149 mmHg, respectively).

Acute hypertension (>200 mmHg) was pronounced in six adult males, two females and one subadult (from the 1999 data subset only). In one case, hypertension developed coincidentally with electroejacula-tion. Although rarely used alone in the domestic dog, ketamine HCl is known to cause increased blood pressure in that species (Ilkiw, 2002). No giant panda appeared to suffer any ill effects from the hypertension episodes. However, complications such as cerebral haemorrhage would be a concern in an anaesthetized giant panda where hypertension is sustained over the course of the procedure (see Chapter 15).

Pulse oximetry revealed that relative oxygen saturation averaged 92% (individual value range 74-100% with a mean of 11 measures per individual). A value of <85% was usually a single datum point that represented a transient fluctuation or a sensor clip placement problem. The generally high and favourable oxygen saturation values were probably related to the relatively light anaesthesia plane provided consistently by ketamine HCl with or without other drug supplementations. Meanwhile, body temperature remained stable throughout the examination, averaging 37.2°C (range 34.2-38.8°C). Heart rate averaged 102 beats per minute (range 62-145) whereas average respiratory rate was 28 breaths per minute (range 12-60).

Body weights, body condition scores and morphometrics

Table 4.1 lists the body weights, BCS ratings and the morphometry measures for all giant pandas that did not meet the criteria of Stunted Development Syndrome (see below) during the 1999 and 2000 survey. Table 4.2 lists those measurements from adult pandas that did meet Stunted Development Syndrome criteria during those two years. In general, most giant pandas were not excessively lean or overweight on the basis of absolute weight or our subjective categorisation of body condition. The greatest variation in BCS occurred in the adult group (Table 4.1). The various morphometry measures found in the remainder of this table can be considered 'normal' for animals meeting our criteria for an adult, subadult or juvenile. There was no impact (p > 0.05) of gender on these variables. Thus, a male and female at a given age generally have comparable weights, body conditions and morphometries.

Clinical pathology

Data on blood values for all giant pandas examined (with stunted and other abnormal animals excluded) are illustrated in Table 4.3; the blood values for just those pandas affected by Stunted Development Syndrome are in Table 4.4. For the former, we have provided these 'normative' data on the basis of our three age classifications: adult; subadult; and juvenile. There were no differences on the basis of age and sex. Further, the values in general appeared consistent with published haematology and chemistry values for the free-living black bear (Storm et al, 1988; DelGiudice et al., 1991) and the giant panda (Mainka, 1999). Because of sample size differences, it was not possible to compare the normal size and stunted groups statistically but no major differences were apparent.

Table 4.1. Age, body weight and selected physical measurements of giant pandas without Stunted Development Syndromea

Adult Subadult Juvenile

Table 4.1. Age, body weight and selected physical measurements of giant pandas without Stunted Development Syndromea

Adult Subadult Juvenile

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