Procedure—Each bird was anesthetized via mask with
isoflurane, intubated, and connected to a pressure-limited
intermittent-flow ventilator. Respiratory rate was
altered while holding peak inspiratory pressure constant
(5 cm H2O) to achieve a PETCO2 in 1 of 3 ranges:
< 30 mm Hg, 30 to 40 mm Hg, and > 40 mm Hg. Blood
was collected from the superficial ulnar artery of each
bird at least once during each of the 3 ranges. Arterial
blood samples were collected for blood gas analysis
while PETCO2 was recorded simultaneously.
Results—A strong correlation between PETCO2 and
PaCO2 was detected over a wide range of partial pressures,
although PETCO2 consistently overestimated
PaCO2 by approximately 5 mm Hg. End-tidal partial
pressure of CO2 and PaCO2 also correlated well with
arterial blood pH, and the acute response of the bicarbonate
buffer system to changes in ventilation was
similar to that of mammals.
Conclusions and Clinical Relevance—Results indicated
that PETCO2 reliably estimates PaCO2 in isofluraneanesthetized
African grey parrots receiving IPPV and suggest that IPPV combined with capnography is a
viable option for anesthetic maintenance in avian anesthesia. (J Am Vet Med Assoc 2001;219:1714–1718)
Objective—To determine safety and efficacy of an
anesthetic protocol incorporating medetomidine, ketamine,
and sevoflurane for anesthesia of injured loggerhead
Animals—13 loggerhead sea turtles.
Procedure—Anesthesia was induced with medetomidine
(50 µg/kg [22.7 µg/lb], IV) and ketamine (5
mg/kg [2.3 mg/lb], IV) and maintained with sevoflurane
(0.5 to 2.5%) in oxygen. Sevoflurane was delivered
with a pressure-limited intermittent-flow ventilator.
Heart rate and rhythm, end-tidal partial pressure
of CO2, and cloacal temperature were monitored continuously;
venous blood gas analyses were performed
intermittently. Administration of sevoflurane
was discontinued 30 to 60 minutes prior to the end of
the surgical procedure. Atipamezole (0.25 mg/kg
[0.11 mg/lb], IV) was administered at the end of
Results—Median induction time was 11 minutes
(range, 2 to 40 minutes; n = 11). Median delivered
sevoflurane concentrations 15, 30, 60, and 120 minutes
after intubation were 2.5 (n = 12), 1.5 (12), 1.25
(12), and 0.5% (8), respectively. Heart rate decreased
during surgery to a median value of 15 beats/min (n =
11). End-tidal partial pressure of CO2 ranged from 2 to
16 mm Hg (n = 8); median blood gas values were
within reference limits. Median time from atipamezole
administration to extubation was 14 minutes
(range, 2 to 84 minutes; n = 7).
Conclusions and Clinical Relevance—Results suggest
that a combination of medetomidine and ketamine
for induction and sevoflurane for maintenance
provides safe, effective, controllable anesthesia in
injured loggerhead sea turtles. (J Am Vet Med Assoc
Objective—To evaluate the cardiopulmonary effects
of immobilizing doses of xylazine-ketamine (XK),
medetomidine-ketamine (MK), medetomidine-ketamine-
acepromazine (MKA), and medetomidine-butorphanol-
ketamine (MBK) in captive red wolves.
Animals—32 adult captive red wolves.
Procedure—Wolves were randomly assigned to 1 of 4
treatment groups: XK, MK, MKA, or MBK. Physiologic
variables measured included heart rate, blood pressure,
respiratory rate, tidal volume, oxygen-hemoglobin
saturation (SpO2), end-tidal CO2, arterial blood gases,
and rectal temperature. Induction time, muscle relaxation,
and quality of recovery were assessed.
Results—Heart rates were lower in wolves in the MBK
group than for the other groups. All 4 drug combinations
induced considerable hypertension, with diastolic
pressures exceeding 116 mm Hg. Blood pressure was
lowest in wolves receiving the MBK combination.
Respiratory rate was significantly higher in wolves
receiving XK, MK, and MKA. Tidal volumes were similar
for all groups. Wolves receiving XK, MK, and MKA
were well-oxygenated throughout the procedure (SpO2
> 93%), whereas those receiving MBK were moderately
hypoxemic (87% < SpO2 < 93%) during the first
20 minutes of the procedure. Hyperthermia was
detected initially following induction in all groups.
Conclusions and Clinical Relevance—The α2-
adrenoceptor agonist-ketamine combinations provide
rapid reversible anesthesia for red wolves but cause
severe sustained hypertension. Such an adverse
effect puts animals at risk for development of cerebral
encephalopathy, retinal hemorrhage, pulmonary
edema, and myocardial failure. Although the MBK
combination offers some advantages over the others,
it is advised that further protocol refinements be
made to minimize risks associated with acute hypertension.
(J Am Vet Med Assoc 2000;217:1366–1371)