Ultrasound-Guided Dorsolateral Approach for Quadratus Lumborum Block in Rabbits (Oryctolagus cuniculus): A Prospective, Randomized, Blinded, Cadaveric Study Comparing Four Different Injectate Volumes.

Ultrasound-guided (US-guided) loco-regional anesthesia can provide significant analgesia and anesthetic-sparing effects when used in rabbits. The aims of this study were to investigate the thoraco-lumbar anatomy of the rabbits, particularly the quadratus lumborum (QL) muscle, to design an appropriate US-guided quadratus lumborum block (QLB) specific for rabbits, and to define the most adequate volume of injectate required to consistently cover the ventral branches of T11 to L3 without affecting the pelvic limb innervation (L4, L5 and L6). Sixteen adult rabbit cadavers were included in the study. After randomization, four different volumes of injectate (0.1 mL/kg, 0.2 mL/kg, 0.3 mL/kg and 0.4 mL/kg) were tested, with these volumes additionally randomized to two sites of injection (right or left QL fascia). An ultrasound-guided QLB was performed with a solution of lidocaine, iodinated contrast and tissue dye (in a proportion of 3:1:1 volume, respectively), with subsequent computed tomography (CT) and anatomical dissection, to evaluate the spread of the injectate. In all but one case, the US-guided QLB performed with a dorsolateral approach using 0.3 mL/kg was adequate, while a dose of 0.4 mL/kg consistently reached the targeted nerves but also extended to L4 and caudally. This may suggest that an injectate volume of 0.3 mL/kg may be the most appropriate to produce adequate spread while not affecting pelvic limb innervation.

Correction: Felisberto et al. Ultrasound-Guided Saphenous Nerve Block in Rabbits (Oryctolagus cuniculus): A Cadaveric Study Comparing Two Injectate Volumes. Animals 2022, 12, 624.

The authors wish to make the following correction to this paper [...].

Ultrasound-Guided Saphenous Nerve Block in Rabbits (Oryctolagus cuniculus): A Cadaveric Study Comparing Two Injectate Volumes.

Ultrasound-guided (US-guided) loco-regional anesthesia techniques allow direct visualization and blockade of sensory nerves. The saphenous nerve (SN), a terminal branch of the femoral nerve (FN), is strictly a sensory nerve for which electrical locator devices are ineffective for localization as no effector muscle contractions can be evoked. US-guided SN block in species other than rabbits produces hind-limb analgesia without affecting FN motor function. The aims of this study were to develop a US-guided SN block technique in rabbits and to compare the spread obtained using two different dye volumes. Twelve hind-limbs from six cadavers (1.62 ± 0.1 kg) were included; after randomization, the SN block was performed on the right or left hind-limb, injecting 0.05 mL kg-1 or 0.1 mL kg-1 of tissue dye in lidocaine (1:50 v:v). Subsequent dissections allowed nerve staining measurements. All SNs were identified, and 17.8 ± 4.6% and 31.0 ± 8.9% of the SN length were stained using low-volume and high-volume of the dye, respectively. Regardless of the volume used, the SN was consistently stained while the motor branch of the FN was not. This US-guided technique may provide hind-limb analgesia without affecting FN motor function in rabbits undergoing mid-distal hind-limb surgeries.

Validation of oscillometric blood pressure measurement using a Datex S/5 Compact multiparameter monitor in anaesthetized adult dogs.

OBJECTIVE: To compare noninvasive (NIBP) with invasive blood pressure (IBP) measurements from a Datex S/5 Compact monitor in anaesthetized adult dogs, and to evaluate it according to the American College of Veterinary Internal Medicine (ACVIM) and the Association for the Advancement of Medical Instrumentation (AAMI) criteria. STUDY DESIGN: Prospective clinical study. ANIMALS: A group of 34 client-owned adult dogs. METHODS: Dogs were anaesthetized for different surgical procedures using different anaesthetic protocols. IBP was measured using a catheter placed in a dorsal pedal artery. A blood pressure cuff was placed over the contralateral dorsal pedal artery for NIBP measurement. Data were recorded using the Datex iCollect program, and paired readings were matched every 3 minutes for 60 minutes. Bland-Altman and error grid analyses were used to estimate the agreement between IBP and NIBP measurements, and its clinical significance, respectively. Data were reported as mean bias [lower, upper limits of agreement (LoA)]. RESULTS: The Datex S/5 monitor conformed to most ACVIM criteria. The correlation coefficient was less than 0.9 for systolic, diastolic, and mean arterial pressures (MAP). The best agreement between the noninvasive and invasive methods was observed for MAP, with LoA (-17 to 13 mmHg) and higher percentage of NIBP readings within 5 (55.6%), 10 (81.7%) and 20 (98.6%) mmHg of the IBP values. The Datex S/5 NIBP technology did not meet the AAMI validation criteria and less than 95% of the paired measurements were found within the green zone of the error grid analysis. CONCLUSIONS AND CLINICAL RELEVANCE: The Datex S/5 monitor conformed to most ACVIM criteria but not with the more rigorous AAMI standards. Despite good agreement between IBP and NIBP for MAP measurements, care must be taken when using this device to guide therapeutic interventions of blood pressure in anaesthetized healthy adult dogs.

Peripheral blood cell ratios as prognostic factors in canine diffuse large B-cell lymphoma treated with CHOP protocol.

Diffuse large B-cell lymphoma (DLBCL) is the most common haematopoietic tumour in dogs and recognized as clinical model for its human counterpart. Recently, neutrophil-to-lymphocyte (NLR) and lymphocyte-to-monocyte (LMR) ratios have been shown to predict time-to-progression (TTP) and lymphoma-specific survival (LSS) in dogs with DLBCL treated with CHOP-based chemotherapy. We retrospectively evaluated in 59 dogs diagnosed with DLBCL the prognostic value of haematological parameters and derived ratios: NLR, LMR, platelet-to-lymphocyte (PLR) and platelet-to-neutrophil (PNR) ratios for TTP, LSS and associated secondary end-points (time-to-progression-rate [TTPR] and lymphoma-specific survival-rate [LSSR]) as rates at 180 and 365 days. PNR is an independent prognostic marker (p ≤ .001) for TTPR/180 and 365 days, dogs with a PNR above 0.032 were more likely to progress before 180 days (sensitivity 46.5%, specificity 87.5%, p = .004). On univariate analysis, NLR showed a prognostic significance for LSSR/180 (p = .006) and LSSR/365 (p = .009). A baseline NLR value below 7.45 was positively associated with survival at 180 days (sensitivity 52%, specificity 85.3%, p = .025). The presence of substage b, was associated with early progression and decreased survival at 180 days (p = .031). Anaemia significantly reduced LSSR at 365 days (p = .028). This is the first study evaluating PLR and PNR in canine DLBCL and demonstrates that PNR could be a predictor of early lymphoma progression. Since peripheral blood cell composition can be affected by several non-oncological causes, the development of larger multicenter studies with homogeneous inclusion criteria could help to better determine the true predictive values of blood cell ratios in dogs' DLBCL treated with CHOP chemotherapy.

Canine lymphoma and vector-borne diseases: Molecular and serological evaluation of a possible complicity.

Lymphoma is the most common haematological malignancy in dogs and its aetiology is largely unknown. The presence of canine vector-borne agents (CVBD) in lymphoma tissues has been described and its causative effects questioned. We intended to evaluate the presence and extent of Leishmania infantum, Ehrlichia canis, Anaplasma phagocytophilum and Bartonella henselae infection in dogs with lymphoma. Sixty-one dogs, living in the Lisbon metropolitan area, with a diagnosis of lymphoma were enrolled. Immunofluorescence assays were used to detect serum IgG's. The presence of DNA from CVBD agents in tumour tissue was assessed by PCR. All dogs tested negative for B. henselae, A. phagocytophilum and E. canis by both serology and PCR. Regarding L. infantum, 8.2% (n = 5) of the dogs had a positive serologic result. L. infantum DNA was detected in two samples of diffuse large B-cell lymphoma (DLBCL). These results show an increased, but not significant, seropositivity (8.2% vs 7.9%) and molecular detection (3.3% vs 1.2%) for L. infantum in dogs with lymphoma, when compared to the reported canine population in the same geographical area. We could not identify an association between lymphoma and E. canis, A. phagocytophilum, B. henselae or Leishmania infantum infection in the studied population. Nevertheless, further studies, following dogs trough their CVBD disease evolution, are worthwhile and may help clarify a possible role of CVBD agents in lymphomagenesis.