Pablo Otero

• MV, PhD
• Professor (Full) at University of Buenos Aires

Peripheral nerve blocks play a critical role in pain management; however, no technique has been described to specifically target the articular nerve branches of the elbow in dogs. This study aimed to develop and compare the success rate of an ultrasound-guided versus a blind pericapsular elbow desensitization (PED) technique in canine cadavers. Pha...

Objective To evaluate risk factors for postoperative intestinal dehiscence, adjusting for potential confounders identified through directed acyclic graphs (DAGs). Methods A retrospective cohort study was conducted of dogs undergoing small intestinal surgery at a private referral center between July 2011 and July 2024. Directed acyclic graphs were...

Objective To assess the splenic flow resistance index (RI) and its response to a fluid bolus in dogs showing circulatory abnormalities upon hospital admission. Design Prospective clinical study. Setting Veterinary referral hospital. Animals Nine dogs with circulatory shock and nine dogs without circulatory abnormalities. Interventions Dogs with...

Determining the cause of death in studies assessing mortality during small animal anesthesia poses challenges due to varying definitions of anesthetic death, limited information, and differences in evaluators’ interpretations. This study aims to establish the interobserver agreement in classifying the cause of death in anesthetized animals. The obs...

Simple Summary Interfascial plane blocks have gained significant attention as a key approach for managing perioperative pain. However, there is limited research on the utilization of a bilateral ultrasound-guided quadratus lumborum block (QLB) on opioid consumption during intraoperative nociception in cats undergoing elective ovariectomy. This stud...

Objective To evaluate if variation in the end‐tidal CO2 partial pressure (∆Petco2) after a fluid challenge could predict fluid responsiveness with a sensitivity of 75% and a specificity of 70% in healthy anesthetized and mechanically ventilated dogs. Design Diagnostic accuracy study. Setting University hospital. Animals Twenty‐seven dogs admitte...

Objective To evaluate the changes in flow velocities of the middle cerebral artery before and after a carotid compression maneuver using transcranial color‐coded duplex sonography (TCCD) in healthy anesthetized dogs under mechanical ventilation. Design Prospective study. Setting University teaching hospital. Animals Eleven healthy adult dogs. I...

Simple Summary The cervical plexus block is commonly used in human medicine to provide analgesia to cervical structures, including dermatomes, lymph nodes, the larynx, the thyroid, parathyroid glands, and carotid vessels. This practice may also hold potential clinical value in veterinary medicine, particularly for dogs, where such a technique has n...

Background Patient safety is essential in small animal anaesthesia. This study aimed to assess anaesthesia‐related deaths in cats worldwide, identify risk and protective factors and provide insights for clinical practice. Methods A prospective multicentre cohort study of 14,962 cats from 198 veterinary centres across different countries was conduc...

Simple Summary The GIN-TONIC block is an interfascial ultrasound-guided regional anesthesia technique that desensitizes the lumbosacral plexus and provides analgesia to the pelvic limb. Different methods have been attempted previously, such as blocking specific plexuses (e.g., lumbar and sacral plexuses) and nerves (e.g., femoral and sciatic). Howe...

Simple Summary This study aimed to assess the efficacy of a sacrococcygeal epidural (ScE) of 0.25% bupivacaine in preventing sympathetic nervous system activation on feline ovariectomy. During the intraoperative period, traditional hemodynamic variables (heart rate, systolic and median blood pressure, and respiratory rate) and Parasympathetic Tone...

Simple Summary Periorbital surgeries are painful procedures that require effective pain management, and regional anaesthesia is an essential tool used to achieve it. To desensitise the area of the head involved, blockade of the branches of the trigeminal nerve (ophthalmic, maxillary, and mandibular nerves) is warranted. This technique is well descr...

This study aimed to evaluate whether the velocity-time integral of aortic blood flow (VTIAo) assessed by transthoracic echocardiography is significantly increased after passive leg-raising maneuver (PLRM) in anesthetized and mechanically ventilated fluid responder pigs. Eight healthy Landrace pigs were anesthetized, mechanically ventilated, and sub...

Simple Summary Brachycephalic dogs are more prone to develop upper airway respiratory complications in the postoperative period. The application of pre- and postoperative continuous positive airway pressure (CPAP) therapy has been suggested in human patients with obstructive sleep apnea to enhance oxygenation, diminish airway swelling, reduce the w...

Simple Summary Regional anaesthesia techniques have been employed for neutering cats, offering effective pain relief. However, there is limited research on the utilisation of an epidural sacrococcygeal (ScE) and ultrasound-guided quadratus lumborum block (QLB) in feline subjects. This study aims to compare the effects of QLB and ScE, both administe...

this study aimed to evaluate the benefits of applying 5 cmH2O of CPAP using a pediatric helmet during the recovery phase from general anesthesia in brachycephalic dogs. Brachycephalic dogs undergoing various surgical procedures were included in the study, and a total of 64 subjects were randomly assigned to receive either standard oxygen supplement...

Background Ensuring patient safety during small animal anaesthesia is crucial. This study aimed to assess anaesthetic‐related deaths in dogs globally, identify risks and protective factors and inform clinical practice. Methods This prospective cohort multicentric study involved 55,022 dogs from 405 veterinary centres across various countries. Data...

Pharmacodynamic understanding of the different local anesthetic concentrations allows adapting their use to diverse clinical/surgical procedures, such as intraoperative and/or postoperative analgesia. A crossover study was performed, where 6 calves (5 male and 1 female), weighing 120 ± 28 Kg, were subjected to combined sciatic and femoral nerve blo...

To evaluate the sensory and motor effects promoted by a combined sciatic and femoral nerve block in calves using two approaches. Six calves were used, in a crossover study. Ultrasound combined with neurostimulation, was used to perform the following block combinations: the proximal approach (PA), which consisted of the association of the parasacral...

El bloqueo del nervio genitofemoral (GF) es una técnica de anestesia regional que consiste en inyectar un anestésico local próximo al GF, en su recorrido abdominal, cercano a la arteria ilíaca externa. La evidencia disponible sugiere que el bloqueo del GF guiado por ecografía, podría servir como una opción analgésica fiable y eficaz para la cirugía...

The lumbar erector spinae plane block entails the injection of a local anesthetic in the lateral aspect of the mammillary process, above the accessory process of the chosen lumbar vertebra, between the multifidus and longissimus lumborum muscles (Medina-Serra et al., 2020). The available evidence suggests that ultrasound-guided erector spinae plane...

Objective: To develop and assess the feasibility, as a diagnostic block, of an ultrasound-guided lateral pericapsular hip desensitization (L-PHD) technique in dogs. Study design: Prospective, randomized, anatomical and feasibility study. Animals: A total of 11 canine cadavers and eight adult dogs scheduled for acetabular surgical denervation....

Objective: To describe the gross and ultrasound anatomy of the parasacral region and an ultrasound-guided greater ischiatic notch (GIN) plane approach aimed at staining the lumbosacral trunk (LST) in canine cadavers. To evaluate if the ultrasound-guided GIN plane approach is non-inferior to the previously described ultrasound-guided parasacral app...

Objective: To evaluate the impact of a 30% end-inspiratory pause (EIP) on alveolar tidal volume (VTalv), airway (VDaw) and physiological (VDphys) dead spaces in mechanically ventilated horses using volumetric capnography, and to evaluate the effect of EIP on carbon dioxide (CO2) elimination per breath (Vco2br-1), PaCO2, and the ratio of PaO2-to-fr...

A 2‐year‐old Göttingen miniature pig was presented for elective ovariectomy. After premedication with ketamine 15 mg/kg and azaperone 2 mg/kg intramuscularly, general anaesthesia was induced with propofol 1.5 mg/kg intravenously. With the animal in sternal recumbency, a 15 × 15 cm area on the dorsolateral aspect of the flank at the level of the sec...

Objective: To describe an ultrasound-guided lateral pre-iliac (LPI) and parasacral (PS) approach in feline cadavers (phase I) and compare the perioperative analgesic use and complications in cats administered LPI and PS blocks (group PNB) or epidural anesthesia (group EPI) for pelvic limb surgery (phase II). Study design: Experimental uncontroll...

Background In medicine, the transversus abdominis plane (TAP) block has been shown as an effective method of analgesia in several surgical procedures. In this context, this prospective, randomized, blinded study aimed to evaluate the analgesic efficacy of TAP block, guided by ultrasound in female dogs submitted to ovariectomy. Methods Therefore, 3...

Objective To evaluate the accuracy of selected echocardiographic variables used to predict fluid responsiveness in hospitalized dogs with compromised hemodynamics and tissue hypoperfusion. Design Diagnostic test study in a prospective cohort of hospitalized dogs. Setting Veterinary referral clinics. Animals Forty‐four hospitalized dogs with comp...

Objective To investigate the injectate spread and nerve staining of ultrasound-guided erector spinae plane (ESP) injections at the thoracolumbar spine in canine cadavers. Study design Prospective, randomized, descriptive, anatomical study. Animals A total of 15 canine cadavers. Methods The location of the medial and lateral branches of the dorsa...

Objective To develop and assess the efficacy of an ultrasound (US)-guided pericapsular hip desensitisation (PHD) technique in dogs. Study design Prospective, randomized, anatomical study and a case series. Animals A total of 30 healthy dogs, eight canine cadavers and seven dogs with hip osteoarthritis. Methods After studying the US anatomy of th...

Transcranial color-coded duplex Doppler sonography (TCCD) is a commonly used tool in human medicine for neuro-intensive monitoring ( Rasulo and Bertuetti, 2019 ). The TCCD allows obtaining and analyzing Doppler flow curve of the artery under evaluation and identifying the systolic peak flow velocity (Vp) and end-diastolic flow velocity (Ved), measu...

The use of transthoracic echocardiography (TTE) and esophageal Doppler (ED) for the measurement of hemodynamic variables in anesthetized dogs was studied. Fourteen mixed-breed dogs, without cardiac disease, undergoing general anesthesia for diagnostic or therapeutic procedures were included in this prospective preliminary study. Dogs were premedica...

Aims: To evaluate the echocardiographic variable tricuspid annular plane systolic excursion normalised to body weight (TAPSEnorm) as a predictor of fluid responsiveness in hospitalised dogs with haemodynamic and tissue perfusion alterations and to investigate the association of left ventricular internal diameter in diastole normalised to body weigh...

Background: To analyze the role of PEEP on dynamic relative regional strain (DRRS) in a model of ARDS, respective maps were generated by electrical impedance tomography (EIT). Methods: Eight ARDS pigs submitted to PEEP steps of 0, 5, 10, and 15 cm H2O at fixed ventilation were evaluated by EIT images. DRRS was calculated as (VT-EIT/EELI)/(VT-EIT...

Objectives To assess the feasibility of an ultrasound (US)-guided quadratus lumborum (QL)-psoas muscle (Pm) interfascial plane injection using a dorsoventral (DV) approach, and to compare needle visualization and distribution pattern between DV and ventrodorsal (VD) approaches. Study design Experimental anatomical study. Animals A total of 14 cat...

A prospective, randomized clinical trial was designed to compare four epidural treatments in dogs undergoing total unilateral mastectomy. The epidural volume of injectate was based on the individual occipito-coccygeal length (OCL) aiming to reach the first thoracic vertebra (T1). The first ten dogs were allocated in a control group (C) and did not...

Transversus abdominis plane (TAP) block is a regional anaesthetic technique used to desensitize the abdominal wall in pigs. The present pilot study aimed to identify anatomical features and assess spread of methylene blue dye, 0.3 mL kg-1 per injection point, in pig cadavers using combined caudal retrocostal and lateral approach. Fresh cadavers fro...

Effective multimodal analgesia techniques are required when pigs are used as models in orthopedic human research. Regional anesthesia is a widely used technique to provide perioperative analgesia in animals undergoing orthopedic surgery. The brachial plexus (BP) block is indicated to desensitize the forelimb in many species but has not been yet des...

The current COVID-19 pandemic has led the world to an unprecedented global shortage of ventilators, and its sharing has been proposed as an alternative to meet the surge. This study outlines the performance of a preformed novel interface called ’ACRA’, designed to split ventilator outflow into two breathing systems. The ’ACRA’ interface was built u...

Simple Summary Desensitizing the femoral nerve improves pain control in several species undergoing pelvic limb surgeries. Despite possible advantages, this method has not yet been described in pigs, although they make an accepted surgical animal model. We developed an approach for femoral nerve blockade using ultrasound guidance in pigs which could...

Objectives The aim of this study was to determine the occurrence of dural puncture, indicated by cerebrospinal fluid (CSF) outflow, in cats receiving neuraxial anesthesia through a lumbosacral injection guided by a pop sensation method. Methods This was an observational, retrospective study. Cats that were scheduled for lumbosacral neuraxial anest...

Aims To evaluate associations between clinicopathological variables and hypercapnia measured in cats with decompensated chronic kidney disease (CKD) on admission to a veterinary hospital. Methods This is a retrospective, cross-sectional study of cats (n=39) that presented to a tertiary veterinary hospital in Argentina between June 2015 and Decembe...

Objectives To describe the ultrasonographic (US) anatomy of the sublumbar region at the level of the second lumbar vertebra (L2), to assess the feasibility of US-guided quadratus lumborum (QL) injections and to evaluate the dye distribution pattern in feline cadavers. Study design Descriptive feline cadaver study Animals A total of eight cat cada...

In this work a shared pressure-controlled ventilation device for two patients is considered. By the use of different valves incorporated to the circuit, the device enables the restriction of possible cross contamination and the individualization of tidal volumes, driving pressures, and positive end expiratory pressure PEEP. Possible interactions in...

Objective To develop an ultrasound-guided dorsal approach to the brachial plexus and to investigate the nerve distribution and staining of a dyed injectate in common kestrel (Falco tinnunculus) cadavers. Study design Prospective, cadaver study. Animals A group of three common kestrel cadavers (6 wings). Methods All cadavers were fresh-frozen at...

Transversus abdominis plane (TAP) block is a regional anesthetic technique used to desensitize the abdominal wall in several species. This study aimed to describe the anatomical characteristics of the abdominal wall and to identify a feasible approach for an US-guided TAP injection that would result in adequate staining of the relevant nerves in th...

Peripheral nerve blocks are indicated for the alleviation of perioperative pain, chronic pain, and traumatic pain of the shoulder, brachium, antebrachium, carpus, metacarpus, and phalanges. They may be used as a primary analgesic procedure or more commonly as part of a multimodal analgesic approach to small animals with acute and chronic pain as in...

Peripheral nerve blocks of the hindlimb are indicated for numerous clinical and surgical procedures, and they can in some cases replace neuraxial anesthesia techniques. The use of point‐of‐care ultrasound (POCUS) nerve blocks and the use of ultrasound for visualizing structures may reduce both failure and complication rates associated with many of...

Peripheral nerve blocks of the trunk are indicated to provide perioperative analgesia in animals having intrathoracic, thoracic wall, abdominal or mammary surgery. The use of point‐of‐care ultrasound (POCUS) nerve blocks improves success while reducing complications over blind techniques. This chapter discusses the uses and limitations of POCUS ner...

Ultrasound allows differentiation of the bony structures and the contents of the spinal canal, such as ligaments, meninges, spinal cord, and nerve roots. Additionally, it is useful to determine the path and depth of needle introduction. This chapter identifies regional anatomy of the vertebral column and also identifies the contents of the spinal c...

Objectives To evaluate the use of 0.7 mA as a fixed electrical current to indicate epidural needle placement and to confirm that 0.7 mA is greater than the upper limit of the minimal electrical threshold (MET) for sacrococcygeal epidural needle placement in dogs. Study design Prospective clinical study. Animals A group of 20 client-owned dogs. M...

Objective To evaluate the evidence of analgesic efficacy of tramadol for the management of postoperative pain and the presence of associated adverse events in dogs. Databases used A comprehensive search using Pubmed/MEDLINE, LILACS, Google Scholar and CAB databases with no restrictions on language and following a prespecified protocol, was perform...

Objective To describe the sonoanatomy of the abdominal wall in live cats and to compare the distribution pattern of two versus three ultrasound-guided transversus abdominis plane (TAP) injections using clinically applicable volumes of lidocaine-dye solution in cat cadavers. Study design Prospective anatomical study. Animals A total of eight clien...

Objective To assess the agreement between an oscillometric device and invasive blood pressure measurements in anesthetized healthy adult guinea pigs. Study design Prospective experimental study. Animals A total of eight adult Hartley guinea pigs. Methods All animals were anesthetized; a carotid artery was surgically exposed and catheterized for...

Objective To develop an ultrasound-guided approach to intercostal nerve injection and to compare the success rate of intercostal nerve injections using blind or ultrasound-guided technique in canine cadavers. Study design Prospective, randomized, descriptive, experimental anatomic study. Animals A total of 14 mid-sized adult canine cadavers. Met...

A 26‐day‐old Pustertaler Sprinzer calf was referred to the ruminant clinic of the Veterinary University of Vienna for internal fixation of a suspected traumatic radius–ulnar fracture of the left forelimb. Preanaesthetic medication consisted of xylazine 0.06 mg/kg and ketamine 6 mg/kg intramuscularly, followed by induction of anaesthesia with ketami...

Objective To compare the perioperative use of analgesics and complication rates in dogs administered an erector spinae plane (ESP) block or a traditional opioid-based (OP) treatment as part of analgesic management during hemilaminectomy. Study design Retrospective cohort study. Animals Medical records of 114 client-owned dogs. Methods General da...

Objective To compare the dye distribution following either two lateral abdominal or one lateral abdominal and one subcostal ultrasound-guided transversus abdominis plane (TAP) injections of a clinically relevant volume of dye solution in dogs. Study design Randomized cadaveric study. Animals A total of eight canine cadavers. Methods On one side...

A well‐balanced multimodal pain management including local anaesthetic techniques was used to provide perioperative analgesia in a horse undergoing partial phallectomy. This surgical intervention has been associated with moderate to severe pain and may present additional challenges to the veterinarian when providing pain relief postoperatively. In...

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-guid...

Objective To describe a lateral ultrasound (US)-guided approach to the radial, ulnar, median and musculocutaneous (RUMM) nerves through a single proximal in-plane insertion in cats and to determine whether one or two injection points are required to successfully stain all the target nerves. Study design Prospective study. Animals A total of eight...

A cat was anaesthetised with midazolam and alfaxalone for a pelvic limb amputation due to a metatarsal fracture complicated with soft tissue necrosis. The femoral nerve and lumbosacral trunk were blocked with ropivacaine 0.75 per cent using a combined ultrasound/nervestimulation‐guided approach. Anaesthesia was maintained with end‐tidal concentrati...

Objective To compare between the nerve stimulation test (group NS) and running-drip method (group RUN) for successful identification of the sacrococcygeal (SCo) epidural space prior to drug administration in dogs. Animals A total of 62 dogs. Study design A randomized clinical study. Methods Dogs requiring an epidural block as part of the multimo...

This study aimed to describe the anatomical distribution of dye injected in the erector spinae plane (ESP) in a porcine living model, which could aid to reveal factors potentially relevant to the unexplained clinical effects of the ESP block. Six pigs received 0.6 mL/kg of 0.25% new methylene blue at the level of the sixth thoracic vertebra through...

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...

Background: Difference between Bohr and Enghoff dead space are not well described in ARDS patients. We aimed to analyze the effect of PEEP on the Bohr and Enghoff dead spaces in a model of ARDS. Methods: 10 pigs submitted to randomized PEEP steps of 0, 5, 10, 15, 20, 25 and 30 cm H2O were evaluated with the use of lung ultrasound images, alveola...

Objective: To investigate the distribution and nerve staining of two volumes of lidocaine-dye solution after ultrasound-guided erector spinae plane (ESP) injections in canine cadavers. Study design: Experimental cadaveric study. Animals: A total of nine canine cadavers. Methods: ESP injections were performed between the longissimus thoracis...

This study aims to compare the nerve stimulator test and the running-drip method for successful identification of the sacrococcygeal (SCo) epidural space prior to drug administration in dogs. Sixty-two dogs receiving an epidural block as part of the multimodal anaesthetic plan were randomly allocated to one of the two study groups. In group NS the...