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Biomedical subjects

P H Cribb

Publications and source records attributed to P H Cribb.

14 recordsLinked to original sources

Comparative cardiopulmonary effects of carfentanil-xylazine and medetomidine-ketamine used for immobilization of mule deer and mule deer/white-tailed deer hybrids.

Three mule deer and 4 mule deer/white-tailed deer hybrids were immobilized in a crossover study with carfentanil (10 microg/kg) + xylazine (0.3 mg/kg) (CX), and medetomidine (100 microg/kg) + ketamine (2.5 mg/kg) (MK). The deer were maintained in left lateral recumbency for 1 h with each combination. Deer were immobilized with MK in 230+/-68 s (mean +/- SD) and with CX in 282+/-83 seconds. Systolic, mean and diastolic arterial pressure were significantly higher with MK. Heart rate, PaO2, PaCO2, pH, and base excess were not significantly different between treatments. Base excess and pH increased significantly over time with both treatments. Both treatments produced hypoventilation (PaCO2 > 50 mm Hg) and hypoxemia (PaO2 < 60 mm Hg). PaO2 increased significantly over time with CX. Body temperature was significantly (P<0.05) higher with CX compared to MK. Ventricular premature contractions, atrial premature contractions, and a junctional escape rhythm were noted during CX immobilization. No arrhythmias were noted during MK immobilization. Quality of immobilization was superior with MK, with no observed movement present for the 60 min of immobilization. Movement of the head and limbs occurred in 4 animals immobilized with CX. The major complication observed with both of these treatments was hypoxemia, and supplemental inspired oxygen is recommended during immobilization. Hyperthermia can further complicate immobilization with CX, reinforcing the need for supplemental oxygen.

Adrenergic alpha-Agonists↗

Advantages and guidelines for using methoxyflurane.

Methoxyflurane anesthesia is particularly useful for orthopedic surgery (muscle relaxation, analgesia, and slow recovery), ophthalmic surgery (central eye position), and small laboratory animals (high therapeutic index and slow induction).

Anesthesia, Inhalation↗

Precautions when using antiprostaglandins.

Antiprostaglandins are effective for relief of pain of low to moderate intensity. The majority of these agents interfere with clotting function, and they should not be used on animals with potential coagulopathies. With high dosage or long-term treatment, gastrointestinal irritation and ulceration are probable. NSAIDs should not be used in conjunction with methoxyflurane because of the potential for renal damage. Care should be taken to avoid hypotension with any anesthetic to obviate renal complications.

Animals↗

Clinical evaluation of enflurane in the dog.

Enflurane (Ethrane; Abbott Laboratories Ltd), a new inhalation anaesthetic, was used on 30 clinical cases. A surgical plane of anaesthesia was quickly obtained and recovery was rapid. Respiratory depression occurred with a reduction in rate which was more marked in deeper planes of anaesthesia. Hypotension was not severe and was more marked in deeper plans of anaesthesia. Clinically the agent did not appear to be a good analgesic. No signs of spontaneous muscle activity were seen, possibly due to premedication with acepromazine.

Anesthesia, Inhalation↗

Capnographic monitoring during anesthesia with controlled ventilation in the horse.

Forty-five horses were maintained on halothane or isoflurane anesthesia for at least 90 minutes and received positive pressure ventilation after the first 30 minutes of anesthesia. Parameters monitored included end-tidal partial pressure of carbon dioxide (ETPCO2), arterial blood pressure, and arterial blood gases and pH. There was a statistically significant correlation between end-tidal carbon dioxide and arterial partial pressure of carbon dioxide (PaCO2) for both halothane and isoflurane anesthesia. There was no significant correlation between end-tidal carbon dioxide and either body weight or systolic blood pressure. No statistically significant difference was found in arterial to end-tidal carbon dioxide difference nor in alveolar dead space because of time or positioning over anesthetic periods of up to 3 hours. It is concluded that end-tidal carbon dioxide monitoring is a satisfactory measure of changes in respiratory acid-base balance with inhalation anesthesia in horses when ventilation is controlled.

Anesthesia, Inhalation↗

The analgesic effects of administering fentanyl or medetomidine in the lumbosacral epidural space of cats.

The analgesic effects of fentanyl (4 micrograms/kg) and medetomidine (10 micrograms/kg) in 1 mL saline injected epidurally were measured in 15 cats. The response to an electrical cutaneous stimulus from a constant current generator was used as the index of analgesia. The stimulus was applied to a forelimb before epidural injection, and at 15, 30, 60, 90, 120, 180, 240, and 300 minutes post-injection (PI). The hindlimb was tested 5 minutes later. One mL saline only was used to control for volume of injection and saline. Medetomidine significantly increased the pain threshold for the hindlimb at 20 to 245 minutes PI compared with the preinjection level. Fentanyl significantly increased the pain threshold at 20 minutes PI only compared with preinjection levels. Medetomidine significantly increased the pain threshold of the forelimb at 15 to 120 minutes PI compared with the preinjection levels. Fentanyl did not significantly increase the pain threshold of the forelimb. Administration of medetomidine produced emesis in 12 of 15 cats in an average of 6.4 minutes PI (range, 3 to 11 minutes) and mild sedation in all cats. Injection of fentanyl produced no visible side effects in any of the cats.

Analgesia, Epidural↗

The cardiopulmonary effects of placing fentanyl or medetomidine in the lumbosacral epidural space of isoflurane-anesthetized cats.

The cardiopulmonary effects of fentanyl (4 micrograms/kg) or medetomidine (10 micrograms/kg) in saline injected epidurally were measured for 2 hours in 15 isoflurane (2.4%)-anesthetized cats. One milliliter of saline without drug was used to control for saline and volume of injection. Baseline was taken as preinjection time 0. Medetomidine significantly increased (P < .05) mean arterial blood pressure (MAP) 5 to 20 minutes postinjection (PI) compared with baseline. MAP significantly decreased 30 to 120 minutes PI compared with baseline. Fentanyl significantly decreased MAP 5 to 120 minutes PI compared with baseline. Heart rate and respiratory rates significantly decreased in the medetomidine and fentanyl groups 5 to 120 minutes PI compared with baseline. Arterial pCO2 significantly increased while arterial pH significantly decreased 15 to 120 minutes PI in the fentanyl and medetomidine groups compared with baseline. Blood bicarbonate concentration significantly increased 90 to 120 minutes PI in the medetomidine group compared with baseline.

Analgesia, Epidural↗

Modification of a nonrebreathing circuit adapter to prevent barotrauma in anesthetized patients.

Barotrauma, pneumothorax, and pneumomediastinum occurred in two anesthetized cats in which the waste gas outlet of a nonrebreathing circuit was occluded. To prevent any similar cases of barotrauma, we have modified our nonrebreathing circuit adapters by inserting a 15 cm H2O PEEP valve into the gas pathway of the nonrebreathing circuit adapter. This PEEP valve prevents the circuit and airway pressures from exceeding 15 cm H2O if the pop-off valve of the nonrebreathing circuit adapter is inadvertently left closed.

Anesthesia↗

Postoperative analgesic and cardiopulmonary effects in dogs of oxymorphone administered epidurally and intramuscularly, and medetomidine administered epidurally: a comparative clinical study.

Thirty dogs undergoing pelvic or hindlimb orthopedic surgery were each administered one of the following postoperative treatments: intramuscular oxymorphone 0.15 mg/kg (OIM) (n = 10); epidural oxymorphone 0.05 mg/kg, (OEP) (n = 10); or epidural medetomidine, 0.015 mg/kg (MEP) (n = 10). Heart rate (HR), respiratory rate (RR), and arterial blood pressure were measured before drug injection and 15, 30, 60, 90, 120, 180, 240, 300, 360, 420, and 480 minutes postinjection (PI). Arterial blood gas analysis was performed before and 15, 30, 60, 90, 120, 180, 360, and 480 minutes PI. The duration of analgesia with OEP, 7.62 + 0.30 hours (mean +/- SEM), and MEP, 7.06 + 0.50 hours, was significantly (P < .05) longer than the 4.91 + 0.44 hours obtained with OIM. All treatments resulted in a significant decrease in HR. Four dogs receiving epidural medetomidine each had second degree atrioventricular (AV) block associated with sinus arrhythmia for a brief period during the first 20 minutes after injection. There was no significant difference in arterial blood pressure between OIM and OEP but arterial blood pressure was significantly higher with MEP than with OIM. MEP can provide analgesia comparable with OEP, but bradycardia and second degree AV block will develop in some cases.

Analgesics, Non-Narcotic↗

Comparison of plasma fentanyl concentrations by using three transdermal fentanyl patch sizes in dogs.

OBJECTIVE: To compare plasma fentanyl concentrations attained after the application of three transdermal fentanyl patch sizes (50, 75, and 100 micrograms/hour) in dogs. DESIGN: Repeated Latin square controlled study. ANIMALS: Six intact, mixed-breed adult dogs (2 males, 4 females) weighing 19.9 +/- 3.4 kg. METHODS: Each dog was randomly assigned to receive each of three treatments: 50 (P50), 75 (P75), or 100 (P100) micrograms/hour transdermal patches. Patches were left in place for 72 hours. Jugular venous blood was collected at 1, 2, 4, 8, 12, 24, 36, 48, 60, and 72 hours after patch application and for 1, 2, 4, 8, and 12 hours after patch removal. Plasma fentanyl concentrations were measured using a radioimmunoassay technique. After a 96-hour washout period, each dog was moved to another treatment group and received a different patch size. RESULTS: The following results were obtained (mean +/- SD): average plasma fentanyl concentration from 24 to 72 hours, 0.7 +/- 0.2 ng/mL (P50), 1.4 +/- 0.5 ng/mL (P75), 1.2 +/- 0.5 ng/mL (P100); the total area under the concentration versus time curve (0 hours to infinity), 46 +/- 12.2 ng/h/mL (P50), 101.2 +/- 41.4 ng/h/mL (P75), 80.4 +/- 38.3 ng/h/mL (P100); and the apparent elimination half-life, 3.6 +/- 1.2 hours (P50), 3.4 +/- 2.7 hours (P75), and 2.5 +/- 2.0 hours (P100). There was a high degree of variability in plasma fentanyl concentrations achieved. Plasma fentanyl concentrations declined rapidly after patch removal. CONCLUSIONS: The attainment of steady-state plasma concentrations takes up to 24 hours, and there is a great deal of variability in the final concentrations reached in different individuals. In this study, the 100 micrograms/hour patches did not provide statistically increased plasma concentrations when compared with the 50 micrograms/hour patches. CLINICAL RELEVANCE: Because of the interindividual and intraindividual variation in plasma fentanyl concentrations, patches should be applied 24 hours before the anticipated time that analgesia will be required. Adequacy of analgesia and potentially deleterious side effects, such as sedation and respiratory depression, should be monitored while the patches are in place. Skin reactions may occur, and the patches should be removed if such skin irritation is seen. After the patch is removed, it is expected that analgesia will wane rapidly because of the brief elimination half-life.

Administration, Cutaneous↗