Does heart rate variability using the Newborn Infant Parasympathetic Evaluation index identify postsurgical pain levels and emergence delirium in toddlers? A prospective observational study.

PURPOSE: Children recovering from anesthesia commonly experience early postoperative negative behaviour, caused by pain and emergence delirium. Differentiating the two is challenging in young children. Perioperative pain influences the heart rate variability-derived Newborn Infant Parasympathetic Evaluation (NIPE) index and may also affect emergence delirium. We sought to investigate whether the perioperative NIPE index can discriminate between mild, moderate, or severe pain levels and can detect emergence delirium. METHODS: This prospective observational study enrolled children aged three years or younger undergoing elective adenotonsillectomy, tonsillectomy, or adenoidectomy. The NIPE index, the Faces, Legs, Activity, Cry, Consolability (FLACC) score, and the Pediatric Anesthesia Emergence Delirium (PAED) score were recorded in the postanesthesia care unit (PACU). The primary aim was to investigate the relationship between the postoperative NIPE index and postoperative pain severity. The secondary aims were to evaluate the association between the NIPE index and emergence delirium (PAED ≥ 10) and its delirium-specific (ED-I) and pain-specific (ED-II) components. RESULTS: Sixty-nine children were recruited. In the PACU, the mean (standard deviation [SD]) NIPE values in children experiencing moderate and severe pain were 50 (12) and 49 (14), respectively. These values were significantly lower than the mean (SD) value of 64 (13) observed in children with mild pain (mean difference moderate vs no/mild pain, -14; 95% confidence interval [CI], -17 to -11; P < 0.001, and mean difference severe vs no/mild pain, -17; 95% CI, -20 to -14; P < 0.001, respectively). The NIPE index was significantly lower in children experiencing pain-specific ED-II (mean [SD] NIPE instantaneous [NIPEi] for ED-II 49 [10] vs no ED-II 55 [13]; mean difference, -6; 95% CI, -11 to -2; P = 0.009). The NIPE index was unable to detect emergence delirium (mean [SD] NIPEi for ED, 54 [15] vs no ED, 51 [10]; mean difference, 3; 95% CI, -2 to 8; P = 0.23) or the delirium-specific component ED-I (mean [SD] NIPEi for ED-I, 55 [15] vs no ED-I, 51 [11]; mean difference, 4; 95% CI, 0 to 8; P = 0.06). CONCLUSION: The NIPE index can identify moderate and severe postoperative pain after adenotonsillectomy but not emergence delirium in children aged three years and younger. This discrimination can be valuable in the early postoperative phase when the differentiation between pain and emergence delirium is difficult. STUDY REGISTRATION: ClinicalTrials.gov ( NCT04909060 ); first submitted 26 May 2021.

RéSUMé: OBJECTIF: Les enfants qui se remettent d'une anesthésie font fréquemment preuve d'un comportement négatif en début de période postopératoire. Ce comportement est causé par la douleur et le délire d'émergence, mais il est difficile de les distinguer chez les jeunes enfants. La douleur périopératoire a un impact sur l'indice d'évaluation parasympathique du nouveau-né et du nourrisson (NIPE) dérivé de la variabilité de la fréquence cardiaque et peut également affecter le délire d'émergence. Nous avons cherché à déterminer si l'indice NIPE périopératoire permettait de différencier des niveaux de douleur légers, modérés ou sévères et de détecter le délire d'émergence. MéTHODE: Cette étude observationnelle prospective a recruté des enfants de trois ans ou moins ayant bénéficié d'une adéno-amygdalectomie, d'une amygdalectomie ou d'une adénoïdectomie non urgente. L'indice NIPE, le score FLACC (Faces, Legs, Activity, Cry, Consolability) et le score PAED (Pediatric Anesthesia Emergence Delirium) ont été enregistrés en salle de réveil. L'objectif principal était d'étudier la relation entre l'indice NIPE postopératoire et la sévérité de la douleur postopératoire. Les objectifs secondaires étaient d'évaluer l'association entre l'indice NIPE et le délire d'émergence (PAED ≥ 10) et ses composantes spécifiques au délire (ED-I) et à la douleur (ED-II). RéSULTATS: Nous avons recruté soixante-neuf enfants. En salle de réveil, les valeurs NIPE moyennes (écart type [ET]) chez les enfants souffrant de douleurs modérées et sévères étaient respectivement de 50 (12) et de 49 (14). Ces valeurs étaient significativement inférieures à la valeur moyenne (ET) de 64 (13) observée chez les enfants présentant une douleur légère (différence moyenne modérée vs pas de douleur ou douleur légère, −14; intervalle de confiance [IC] à 95 %, −17 à −11; P < 0,001, et différence moyenne entre douleur sévère vs pas de douleur ou douleur légère, −17; IC 95 %, −20 à −14; P < 0,001, respectivement). L'indice NIPE était significativement plus faible chez les enfants présentant un ED-II spécifique à la douleur (moyenne [ET] NIPE instantanée [NIPEi] pour ED-II, 49 [10] vs pas de ED-II, 55 [13]; différence moyenne, −6; IC 95 %, −11 à −2; P = 0,009). L'indice NIPE n'a pas été en mesure de détecter le délire d'émergence (NIPEi moyen [ET] pour le délire d'émergence, 54 [15] vs pas de délire d'émergence, 51 [10]; différence moyenne, 3; IC 95 %, −2 à 8; P = 0,23) ou la composante spécifique au délire de l'ED-I (NIPEi moyen [ET] pour ED-I, 55 [15] vs pas d'ED-I, 51 [11]; différence moyenne, 4; IC 95 %, 0 à 8; P = 0,06). CONCLUSION: L'indice NIPE permet d'identifier une douleur postopératoire modérée et sévère après une adéno-amygdalectomie mais pas le délire d'émergence chez les enfants de trois ans et moins. Cette discrimination peut être utile dans la phase postopératoire précoce lorsqu'il est difficile de différencier la douleur et le délire d'émergence. ENREGISTREMENT DE L'éTUDE: ClinicalTrials.gov ( NCT04909060 ); première soumission le 26 mai 2021.

Construct validity, responsiveness and reliability of the Feline Grimace Scale in kittens.

OBJECTIVES: The aim of the present study was to investigate the construct validity, responsiveness and reliability of the Feline Grimace Scale (FGS) in kittens. METHODS: A total of 36 healthy female kittens (aged 10 weeks to 6 months) were included in a prospective, randomized, blinded study. Video recordings of all kittens were made before and 1 and 2 h after ovariohysterectomy using an opioid-free injectable anesthetic protocol with or without multimodal analgesia. Additional recordings were taken before and 1 h after administration of rescue analgesia (buprenorphine 0.02 mg/kg IM) to painful kittens. Screenshots of facial images were collected from the video recordings for FGS scoring. Four observers blinded to treatment groups and time points scored 111 randomized images twice with a 5-week interval using the FGS. Five action units (AUs) were scored (ear position, orbital tightening, muzzle tension, whiskers position and head position; 0-2 each). Construct validity, responsiveness, and inter- and intra-rater reliability were evaluated using linear models with Benjamini-Hochberg correction, Wilcoxon signed-rank test and single intraclass correlation coefficients (ICCsingle), respectively (P <0.05). RESULTS: FGS total ratio scores were higher at 1 and 2 h after ovariohysterectomy (median [interquartile range, IQR]: 0.30 [0.20-0.40] and 0.30 [0.20-0.40], respectively) than at baseline (median [IQR]: 0.10 [0.00-0.30]) (P <0.001). FGS total ratio scores were lower after the administration of rescue analgesia (median [IQR] before and after rescue analgesia) 0.40 [0.20-0.50] and 0.20 [0.10-0.38], respectively (P <0.001). Inter-rater ICCsingle was 0.68 for the FGS total ratio scores and 0.35-0.70 for all AUs considered individually. Intra-rater ICCsingle was 0.77-0.91 for the FGS total ratio scores and 0.55-1.00 for all AUs considered individually. CONCLUSIONS AND RELEVANCE: The FGS is a valid and responsive acute pain-scoring instrument with moderate inter-rater reliability and good to excellent intra-rater reliability in kittens.

Glomerular Hyperfiltration: A Marker of Fibrosis Severity in Metabolic Associated Steatotic Liver Disease in an Adult Population.

Glomerular hyperfiltration (GH) is an increase in the glomerular filtration rate, possibly progressing to chronic kidney disease (CKD). Metabolic-associated steatotic liver disease (MASLD) is linked to an increased risk of CKD, especially if fibrosis is present; however, the association between GH and MASLD has not been explored. To evaluate GH prevalence in MASLD and its possible correlation with liver fibrosis. 772 consecutive patients with ultrasound MASLD (mean age 47.3 ± 8.9 years, 67.1% males) were enrolled. GH was defined as estimated glomerular filtration rate (eGFR) greater than the upper quartile of values in the cohort. Liver stiffness measurement (LSM) by FibroScan ≥ 7.2 kPa suggested liver fibrosis. GH was present in 20% of patients, liver fibrosis in 30%. In total, 53.4% of the cohort was obese, 40.9% hypertensive, 36.3% diabetic and 70.8% dyslipidaemic. GH patients compared to non-GH were significantly younger (38.4 ± 8.3 vs. 49.5 ± 7.7, p < 0.001), with higher prevalence of LSM > 7.2 kPa (35.5% vs. 29%, p < 0.001), without any difference in metabolic comorbidities. In multivariate analysis, age (OR 0.85, CI 95% 0.82-0.87) and significant fibrosis (OR 1.83; CI 95%1.10-3.03) remained independently associated with GH, regardless of the presence of metabolic alterations and nephrotoxic drugs. GH, an early marker of renal damage, is highly prevalent in MASLD and is associated with hepatic fibrosis. GH may be considered an early marker of both liver and renal disease and its recognition could prompt the management of risk factors aimed at preventing the progression of both hepatic and renal disease.

Interleukin-6: A New Marker of Advanced-Sarcopenic HCC Cirrhotic Patients.

Hepatocellular carcinoma (HCC) is the major cause of liver-related death worldwide. Interleukin 6 (IL-6) promotes the growth of the HCC microenvironment. The correlation between Child-Pugh (CP) and HCC stage and between HCC stage and sarcopenia is still not clear. Our aim was to investigate whether IL-6 is correlated with HCC stage and could represent a diagnostic marker for sarcopenia. Ninety-three HCC cirrhotic patients in different stages, according to BCLC-2022 (stages A, B, and C), were enrolled. Anthropometric and biochemical parameters, comprehensive of IL-6, were collected. The skeletal muscle index (SMI) was measured using dedicated software on computer tomography (CT) images. IL-6 level was higher in advanced (BCLC C) compared to the early-intermediate (BCLC A-B) stages (21.4 vs. 7.7 pg/mL, p < 0.005). On multivariate analysis, IL-6 levels were statistically dependent on the degree of liver disease severity (CP score) and HCC stages (p = 0.001 and p = 0.044, respectively). Sarcopenic patients presented lower BMI (24.7 ± 5.3 vs. 28.5 ± 7.0), higher PMN/lymphocyte ratio (2.9 ± 2.4 vs. 2.3 ± 1.2) and increased values of log (IL-6) (1.3 ± 0.6 vs. 1.1 ± 0.3). Univariate logistic regression between sarcopenia and log (IL-6) showed a significant odds ratio (OR 14.88, p = 0.044) with an AUC of 0.72. IL-6 appears to be an effective biomarker for the diagnosis of advanced cirrhotic HCC. In addition, IL-6 could be considered a marker of cirrhotic HCC-related sarcopenia, suggesting further investigation with BIA- or CT-dedicated software.

Randomised, prospective, blinded, clinical trial of opioid-free injectable anaesthesia with or without multimodal analgesia in kittens undergoing ovariohysterectomy.

OBJECTIVES: This study compared an opioid-free injectable anaesthetic protocol with or without multimodal analgesia in kittens undergoing ovariohysterectomy. METHODS: In this prospective, randomised, blinded, clinical trial, 29 healthy kittens (mean ± SD weight 1.55 ± 0.46 kg; aged 10 weeks to 6 months) were included. Anaesthesia was performed with an intramuscular injection of ketamine (4 mg/kg), dexmedetomidine (40 µg/kg) and midazolam (0.25 mg/kg). In the multimodal group (MMG), cats (n = 14) received meloxicam (0.1 mg/kg SC) and intraperitoneal bupivacaine 0.25% (2 mg/kg), whereas the same volume of saline was administered in the control group (CG; n = 15). Atipamezole (0.4 mg/kg IM) was given 15 mins after ovariohysterectomy. Postoperative pain was assessed using the UNESP-Botucatu multidimensional feline pain assessment scale - short form. Rescue analgesia (buprenorphine 0.02 mg/kg IM in MMG/CG and meloxicam 0.1 mg/kg SC in CG) was administered if pain scores were ⩾4/12. Soft food intake (after 2 and 60 mins) was evaluated at specific time points postoperatively. Statistical analyses were performed with linear models and post-hoc pairwise comparison with Benjamini-Hochberg corrections (P <0.05). RESULTS: The prevalence of rescue analgesia was higher in the CG (n = 15/15) than the MMG (n = 1/14; P <0.001). Pain scores at 1 h, 2 h and 4 h postoperatively were higher in the CG (4.1 ± 2.8, 4.8 ± 3.0 and 5.3 ± 1.2, respectively) than in the MMG (1.6 ± 1.0, 1.1 ± 1.0 and 0.9 ± 0.8, respectively; P <0.001). Food intake (%) at 1 h postoperatively was higher in the MMG after 2 and 60 mins (10.4 ± 9 and 71.9 ± 29, respectively) than in the CG (1.4 ± 2 and 13.9 ± 7, respectively; P <0.001). CONCLUSIONS AND RELEVANCE: This opioid-free protocol using multimodal analgesia produced adequate postoperative pain relief, while almost eliminating the need for rescue analgesia in kittens undergoing ovariohysterectomy. Pain decreased food intake.

Anesthesia for pediatric magnetic resonance imaging: a review of practices and current pathways.

PURPOSE OF REVIEW: Magnetic resonance imaging (MRI) is an ever-expanding investigation modality in children. This review aims to present current strategies to perform MRI in pediatrics efficiently and safely. The latest evidence on approaches, safety and costs of MRI with no sedation or with sedation provided by anesthesiologists and non-anesthesiologists are outlined and discussed. RECENT FINDINGS: MRI under sedation provided by either anesthesiologists or non-anesthesiologists has a low incidence of minor adverse events and rarely severe complications. Propofol infusion with or without dexmedetomidine appears the ideal anesthetic, as it allows spontaneous breathing and fast turnover. Intranasal dexmedetomidine is safe and the most effective medication when a nonintravenous route is employed.New scanning techniques and patient's preparation methods can increase the chances to successfully perform MRI with no sedation by shortening sequences, reducing artifacts, and improving child's cooperation. SUMMARY: MRI under sedation can be considered safe. Proper patient selection, clear decision-making and medico-legal pathways are particularly necessary for nurse-only sedated scans. Nonsedated MRIs are feasible and cost-effective but require optimal scanning techniques and patient's preparation to be successful. Further research should be focused on identifying the most effective modalities to perform MRI without sedation and clarify protocols for the nurse-only sedations.Anesthesia service will likely remain pivotal for complex and critically ill patients and to provide assistance in case of adverse events.

Analgesic efficacy of an ultrasound-guided transversus abdominis plane block with bupivacaine in cats: a randomised, prospective, masked, placebo-controlled clinical trial.

OBJECTIVES: This randomised, prospective, masked clinical trial evaluated the postoperative analgesic efficacy of an ultrasound-guided transversus abdominis plane block (TAPB) with bupivacaine in cats undergoing ovariohysterectomy. METHODS: Thirty-two healthy adult female cats undergoing elective ovariohysterectomy were randomised to undergo TAPB with bupivacaine (treatment group [TG], n = 16) vs placebo (control group [CG], n = 16) in addition to preoperative analgesia with buprenorphine (0.02 mg/kg IM). All patients received a general anaesthetic and, before surgical incision, a bilateral two-point (subcostal and lateral-longitudinal) TAPB was performed using 1 ml/kg bupivacaine 0.25% (0.25 ml/kg/point) or saline. Each cat was assessed by a blinded investigator before premedication (0 h) and at 1, 2, 3, 4, 8, 10 and 24 h postoperatively using the UNESP-Botucatu Feline Pain Scale - short form. Buprenorphine (0.02 mg/kg IV) and meloxicam (0.2 mg/kg SC) were administered when pain scores were ⩾4/12. Ten hours postoperatively, meloxicam was administered to cats that did not receive rescue analgesia. Statistical analysis included Student's t-tests, Wilcoxon tests and χ2 tests, and a linear mixed model with Bonferroni corrections (P <0.05). RESULTS: Of the 32 cats enrolled, three in the CG were excluded from the analysis. The prevalence of rescue analgesia was significantly higher in the CG (n = 13/13) than in the TG (n = 3/16; P <0.001). Only one cat in the CG required rescue analgesia twice. Pain scores were significantly higher in the CG compared with the TG at 2, 4 and 8 h postoperatively. Mean ± SD pain scores were significantly higher in the CG, but not in the TG, at 2 (2.1 ± 1.9), 3 (1.9 ± 1.6), 4 (3.0 ± 1.4) and 8 h postoperatively (4.7 ± 0.6) than at 0 h (0.1 ± 0.3). CONCLUSIONS AND RELEVANCE: A bilateral ultrasound-guided two-point TAPB with bupivacaine in combination with systemic buprenorphine provided superior postoperative analgesia than buprenorphine alone in cats undergoing ovariohysterectomy.

Evaluation of Nociception during Pediatric Surgery: A Topical Review.

The association between intraoperative nociception and increased patient's morbidity is well established. However, hemodynamic parameters, such as heart rate and blood pressure, may result in an inadequate monitor of nociception during surgery. Over the last two decades, different devices have been marketed to "reliably" detect intraoperative nociception. Since the direct measure of nociception is impractical during surgery, these monitors measures nociception surrogates such as sympathetic and parasympathetic nervous systems responses (heart rate variability, pupillometry, skin conductance), electroencephalographic changes, and muscular reflex arc. Each monitor carries its own advantages and disadvantages. The manuscript aims to give an overview of the most up-to-date information available in the literature on current nociceptor monitors available in clinical practice, with particular focus on their applications in pediatrics.

An Anatomical, Sonographic, and Computed Tomography Study of the Transversus Abdominis Plane Block in Cat Cadavers.

This study compared the distribution of a bupivacaine-iopamidol-dye solution following ultrasound-guided in-plane TAP injection using a 1-point (TAP-L) or 2-point (TAP-SL) approach in cat cadavers. Two cadavers were used to study the TAP sonoanatomy while eight cadavers were enrolled in a randomized, prospective, blinded investigation. Each cat randomly received a TAP-L with 0.5 mL/kg in one hemiabdomen and a TAP-SL with 0.25 mL/kg/point in the contralateral hemiabdomen. After injection, computed tomography and dissection were performed to assess contrast distribution and number of stained target nerves. TAP-SL resulted in a wider contrast spread (mm) compared with TAP-L (87 ± 7 versus 71 ± 9; p = 0.002). The prevalence of nerve staining was higher using TAP-SL than TAP-L (p = 0.001). The ventral branches of T10, T11, T12, T13, L1 and L2 were stained in 2/8, 2/8, 5/8, 7/8, 4/8 and 1/8, and in 7/8, 7/8, 8/8, 8/8, 8/8 and 1/8 using TAP-L and TAP-SL approaches, respectively. Computed tomography and dissection identified minimal injectate intraperitoneally or within the falciform ligament fat following 1 TAP-L and 2 TAP-SL. Ultrasound-guided TAP-SL provided better injectate distribution around the thoracolumbar spinal nerve branches than TAP-L.

Pharmacokinetics of Bupivacaine Following Administration by an Ultrasound-Guided Transversus Abdominis Plane Block in Cats Undergoing Ovariohysterectomy.

Bupivacaine is commonly used for peripheral nerve block in veterinary medicine. This study described the pharmacokinetics of two doses of bupivacaine following administration by an ultrasound-guided transversus abdominis plane (TAP) block in cats undergoing ovariohysterectomy. Twelve healthy female adult cats were included in a randomized, prospective, blinded clinical trial. Anaesthetic protocol included acepromazine-buprenorphine-propofol-isoflurane-meloxicam. Each cat received 1 mL/kg of bupivacaine 0.2% or 0.25% (BUPI-2 and BUPI-2.5, respectively) via bilateral two-point TAP block before surgery (n = 6/group). Plasma concentrations of bupivacaine were detected using liquid chromatography-mass spectrometry. A one-compartment model and non-compartmental analysis described the pharmacokinetic parameters. Bupivacaine was detected up to 480 min (335 ± 76 in BUPI-2 and 485 ± 198 ng/mL in BUPI-2.5). For BUPI-2 and BUPI-2.5, maximum plasma concentrations were 1166 ± 511 and 1810 ± 536 ng/mL at 33 ± 14 and 47 ± 22 min, clearance was 5.3 ± 1.8 and 4.9 ± 1.5 mL/min/kg, and elimination half-life were 253 ± 55 and 217 ± 52 min, respectively. The two doses of bupivacaine via TAP block produced concentrations below toxic levels in cats. A dose of 2.5 mg/kg bupivacaine was safe to be administered using this block in healthy cats.

Multimodal Analgesic Plan for Children Undergoing Chimeric 14.18 Immunotherapy.

Immunotherapy with the chimeric 14.18 anti-GD2 antibody (ch14.18) is associated with severe neuropathic pain. Different analgesic modalities have been employed, but pain management remains challenging and side effects such as desaturation, bradycardia, and hypotension have been reported. We retrospectively analyzed the efficacy of a multimodal regimen based on gabapentin, ketamine, and morphine in controlling pain during ch14.18 chemotherapy. In our cohort, the pain was low, desaturation and hypotension were infrequent, and no episode of bradycardia was reported. Morphine consumption was similar to other studies. Our results suggest that this regimen may be a valid analgesic option in children undergoing ch14.18 infusion.

A novel ultrasound-guided lateral quadratus lumborum block in dogs: a comparative cadaveric study of two approaches.

OBJECTIVE: To describe an ultrasound-guided lateral quadratus lumborum (LQL) block technique and the spread characteristics of lidocaine-dye injected in the LQL plane using a transversal (LQL-T) or a longitudinal (LQL-L) approach. STUDY DESIGN: Experimental anatomic study. ANIMALS: A total of eight canine cadavers. METHODS: Bilateral ultrasound-guided injections in the fascial plane lateral to the quadratus lumborum muscle and medial to the thoracolumbar fascia (LQL plane) with the needle directed at the first lumbar (L1) transverse process were performed using lidocaine-dye (0.3 mL kg-1). Anatomical dissection determined the dye distribution, sympathetic trunk staining and number of spinal nerves stained circumferentially >1 cm. RESULTS: The LQL fascial plane was ultrasonographically recognized in all cadavers and filled with lidocaine-dye in all eight cadavers with the LQL-T approach and in six with LQL-L. The injectate spread ventral to the lumbar transverse processes, around the quadratus lumborum muscle and dorsal to the transversalis fascia, affecting the ventral branches of the spinal nerves and the sympathetic trunk. A median (range) of 4 (3-5) and 3 (0-4) ventral branches of the thoracolumbar nerves were dyed with LQL-T and LQL-L approaches, respectively (p = 0.04). The most cranial nerve stained was the twelfth thoracic (T12) with the LQL-T approach and T13 with LQL-L, and the most caudal was L3 with both approaches. The incidence of sympathetic trunk staining was significantly higher using LQL-T (six injections) compared with LQL-L (one injection; p = 0.04). Dye was not observed in the lumbar plexus, epidural space or abdominal cavity. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasound-guided LQL-T approach resulted in a more consistent spread toward the spinal nerves and sympathetic trunk compared with LQL-L approach. Further studies are necessary to assess the LQL block effectiveness and success rate in live dogs.

Description of ultrasound-guided quadratus lumborum block technique and evaluation of injectate spread in canine cadavers.

OBJECTIVE: To describe a quadratus lumborum (QL) block technique in canine cadavers and the spread of injectate. STUDY DESIGN: Prospective, randomized, descriptive, experimental anatomic study. ANIMALS: A group of 12 adult canine cadavers. METHODS: Gross and ultrasound anatomy of the sublumbar musculature and the relationship with the spinal nerves was studied in two cadavers. Bilateral ultrasound-guided injections were performed in eight cadavers in the fascial plane between the QL and psoas muscle using a dye-lidocaine solution [low volume (LV) 0.15 mL kg-1 or high volume (HV) 0.3 mL kg-1]. The ultrasound transducer was positioned caudal and parallel to the proximal aspect of the last rib, and an insulated needle was introduced in-plane using a ventrolateral to dorsomedial approach. Dissections were performed to determine the number of spinal nerves successfully stained (>1 cm) and the presence of injectate in the epidural space or abdominal cavity. Additionally, two cadavers were transversally cryosectioned after QL injection. RESULTS: Ventral branches of the last thoracic and first three lumbar spinal nerves ran between the bundles of the QL muscle and between the QL and psoas muscles. The target fascial plane was ultrasonographically identified and filled with the dye solution following all injections. Ventral branches of the thirteenth thoracic and first, second and third lumbar nerves were stained by 0.0%, 71.4%, 100%, 100%, and 25%, 100%, 100%, 100% using LV and HV, respectively. Multisegmental spread stained the lumbar sympathetic trunk on 0 (0-3) and 3 (0-4) vertebral levels with LV and HV, respectively. No abdominal or epidural spread was identified. CONCLUSION AND CLINICAL RELEVANCE: Although no significant differences were found, HV resulted in a higher percentage of stain on spinal nerves and sympathetic trunk than LV. Further studies are warranted to determine if the QL block provides somatic and visceral abdominal analgesia in dogs.