OBJECTIVE To assess the isoflurane-sparing effect of a transdermal formulation of fentanyl solution (TFS) and subsequent naloxone administration in dogs.
ANIMALS 6 healthy mixed-breed dogs.
PROCEDURES Minimum alveolar concentration (MAC) of isoflurane was determined in each dog with a tail clamp method (baseline). Two weeks later, dogs were treated with TFS (2.7 mg/kg [1.23 mg/lb]), and the MAC of isoflurane was determined 4 and 24 hours later. After the 4-hour MAC assessment, saline (0.9% NaCl) solution was immediately administered IV and MAC was reassessed. After the 24-hour MAC assessment, naloxone hydrochloride (0.02 mg/kg [0.01 mg/lb], IV) was immediately administered and MAC was reassessed. Heart rate, respiratory rate, arterial blood pressure, end-tidal partial pressure of CO2, and oxygen saturation as measured by pulse oximetry were recorded for each MAC assessment.
RESULTS Mean ± SD MAC of isoflurane at 4 and 24 hours after TFS application was 45.4 ± 4.0% and 45.5 ± 4.5% lower than at baseline, respectively. Following naloxone administration, only a minimal reduction in MAC was identified (mean percentage decrease from baseline of 13.1 ± 2.2%, compared with 43.8 ± 5.6% for saline solution). Mean heart rate was significantly higher after naloxone administration (113.2 ± 22.2 beats/min) than after saline solution administration (76.7 ± 20.0 beats/min). No significant differences in other variables were identified among treatments.
CONCLUSIONS AND CLINICAL RELEVANCE The isoflurane-sparing effects of TFS in healthy dogs were consistent and sustained between 4 and 24 hours after application, and these effects should be taken into consideration when anesthetizing or reanesthetizing TFS-treated dogs.
Objective—To determine the frequency of clinically relevant abnormalities missed by failure to perform a blood smear evaluation in a specific subset of dogs receiving chemotherapy and to compare automated and manual neutrophil counts in the same population
Design—Retrospective case series
Animals—50 dogs receiving chemotherapy with a total nucleated cell count > 4,000 nucleated cells/μL.
Procedures—50 blood smears were evaluated for abnormalities that have strong potential to change the medical plan for a patient: presence of blast cells, band neutrophils, nucleated RBCs, toxic change, hemoparasites, schistocytes, and spherocytes. Automated and manual neutrophil counts were compared.
Results—Blood smears from 10 (20%) patients had ≥ 1 abnormalities. Blast cells were identified on 4 (8%) blood smears, increased nucleated RBCs were identified on 5 (10%), and very mild toxic change was identified on 2 (4%). Correlation coefficient of the neutrophil counts was 0.96. Analysis revealed a slight bias between the automated and manual neutrophil counts (mean ± SD difference, −0.43 × 103/μL ± 1.10 × 103/μL)
Conclusions and Clinical Relevance—In this series of patients, neutrophil count correlation was very good. Clinically relevant abnormalities were found on 20% of the blood smears. An automated CBC appears to be accurate for neutrophil counts, but a microscopic examination of the corresponding blood smear is still recommended; further studies are needed to determine whether the detection or frequency of these abnormalities would differ dependent on chemotherapy protocol, neoplastic disease, and decision thresholds used by the oncologist in the ordering of a CBC without a blood smear evaluation.