Oscillometric and Doppler techniques can provide continuous noninvasive blood pressure readings in cats and dogs: an instructional video.

OBJECTIVE: To provide a video tutorial detailing how to perform continuous noninvasive blood pressure monitoring in dogs and cats. ANIMALS: Any size dog or cat. METHODS: To measure blood pressure noninvasively, a blood pressure cuff is selected on the basis of the circumference of the limb and placed at the level of the right atrium. For oscillometric blood pressure measurement, the cuff is connected to an oscillometric unit that will automatically inflate and deflate the cuff in order to measure the patient's blood pressure using an internal algorithm. For Doppler blood pressure measurement, a sphygmomanometer is used to manually inflate the pressure cuff 30 to 40 mm Hg above the point where the audible arterial sounds disappear. Then, the cuff is gradually deflated until the audible arterial sounds return; the pressure at the first sound is recorded as the blood pressure. To generate continuous readings, the oscillometric machine is set to measure blood pressure as often as every minute. Alternatively, the Doppler crystal is taped to the patient's leg to facilitate repeated cuff inflation/deflation and collection of blood pressure values as often as every minute. RESULTS: Continuous blood pressure readings can be obtained by both the oscillometric and Doppler techniques. CLINICAL RELEVANCE: Continuous blood pressure readings identify trends in a patient's cardiovascular status. The most reliable oscillometric blood pressure reading is the mean arterial pressure. Doppler blood pressure values are considered systolic in dogs. Doppler values in cats underestimate systolic and overestimate mean blood pressure.

Therapeutic interventions using the peritoneal and coelomic cavity in dogs, cats, and exotic pets.

OBJECTIVE: To provide a video tutorial describing intraperitoneal (IP) and intracoelomic (IC) therapeutics (IP/IC fluid therapy, euthanasia, direct peritoneal resuscitation). ANIMALS: Dogs, cats, and exotic pets. METHODS: Peritoneal and coelomic centesis allows for delivery of fluids or to perform euthanasia. The peritoneal and coelomic membranes contain a vast network of capillaries and lymphatics that allow absorption of fluids and blood products. Needles are inserted aseptically IP or IC at species-specific locations to avoid iatrogenic damage. In mammals, the needle is inserted in a periumbilical location at a 1- to 2-cm radius from the umbilicus, while the needle is inserted into the ventral inguinal fossa in chelonians and lateroventrally in lizards and snakes. Direct peritoneal resuscitation is a human technique in which a dextrose/electrolyte solution infused IP reduces ischemia-reperfusion injury, edema, and tissue necrosis to improve mortality in patients with diseases like shock and sepsis or who require acute abdominal surgery. RESULTS: Isotonic crystalloids are given IP/IC at 10- to 20-mL/kg doses (smaller volumes in reptiles) and blood products at standard calculated doses. Sodium pentobarbital without phenytoin (3 mL/4.5 kg) is used for IP/IC euthanasia. CLINICAL RELEVANCE: Being aware of multiple routes for fluid and blood product administration allows treatment in animals for which intravenous or intraosseous catheterization is undesirable or impossible. While intravenous or intraosseous routes are always preferred, especially for resuscitation, familiarity with locations for IP/IC fluid and euthanasia is useful. Techniques like direct peritoneal resuscitation are not currently used in animals but might be translated to veterinary cases in the future.

Clinical Assessment of Primary Hemostasis: A Review.

Primary hemostatic disorders such as thrombocytopenia and thrombocytopathia are commonly encountered in small animal practice. The key stages of primary hemostasis include platelet adhesion, activation, and aggregation. Understanding the interaction between tissues, platelets, and signaling molecules not only helps clinicians comprehend clot formation but also better recognize thrombocytopathias. Although congenital thrombocytopathia is rare, commercially available platelet function tests allow veterinarians to narrow differentials in many clinical settings. Thrombocytopenia can be easily diagnosed in any clinical setting. In this paper, we review the current understanding of primary hemostasis in veterinary medicine, including the clinical presentation and available diagnostics to identify platelet abnormalities.

Interstitial glucose monitoring has acceptable clinical accuracy in juvenile dogs.

OBJECTIVE: To compare the performance of an interstitial glucose monitor (IGM) versus a portable blood glucose monitor (PBGM) in sick juvenile dogs in a veterinary ICU. ANIMALS: 16 client-owned dogs admitted to the university teaching hospital under 1 year of age with systemic illness. PROCEDURES: Paired interstitial and blood glucose samples were collected. A third glucose measurement with a reference method was obtained when IGM and PBGM values were clinically disparate. Analytical accuracy was measured by Pearson correlation and agreement statistics, including mean absolute relative difference (MARD), bias, and 95% limits of agreement. The Parkes consensus error grid analysis was performed to assess clinical accuracy. RESULTS: 159 paired glucose measurements were available for analysis. Comparison of IGM readings to PBGM measurements resulted in an MARD of 15.4% and bias of -2.6%, with the 95% limits of agreement ranging from -42.5% to 37.4%. Positive correlation between IGM and PBGM (Pearson r = 0.65) was found. On consensus error grid analysis, 100% of the pairs fell into clinically acceptable zones (74.2% in zone A, and 25.8% in zone B). When disparate IGM and PBGM readings were compared to a laboratory reference standard (n = 13), both methods resulted in high MARD and wide limits of agreement. CLINICAL RELEVANCE: The IGM provides clinically acceptable glucose measurements compared to PBGM to monitor glucose levels in juvenile dogs in a clinical setting. Further clinical studies with a larger sample size, particularly in the hypoglycemic range, are needed to assess IGM performance in the lower glucose range.

Comparison of a commercial immunochromatographic strip crossmatch kit and standard laboratory crossmatch methods for blood transfusion compatibility in dogs.

OBJECTIVE: To evaluate agreement between 2 standard laboratory (SL) methods and an immunochromatographic strip (ICS) method to crossmatch dogs receiving RBC transfusions. A second objective was to evaluate uninterpretable SL crossmatch results as compared to ICS in the presence of autoagglutination. DESIGN: Prospective observational study (September 2018 to October 2019). SETTING: University teaching hospital. ANIMALS: Forty anemic dogs receiving RBC transfusions. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: All dogs received DEA 1-negative packed RBCs. Three crossmatch methods were evaluated against the same unit transfused to each dog: SL method performed at institutional laboratory (SL-I), SL method sent to a commercial laboratory (SL-C), and a commercially available point-of-care ICS method. Major and minor crossmatches were incompatible for 2.5%/7.5% of ICS tests, 82.5%/52.5% of SL-I tests, and 52.5%/27.5% of SL-C tests. Agreement between ICS and SL-C major (κ = 0.05) and minor (κ = 0.02) crossmatches and between ICS and SL-I major (κ = 0.009) and minor (κ = 0.03) crossmatches was slight. Agreement between SL-C and SL-I major (κ = -0.06) and minor (κ = -0.12) crossmatches was poor. Results of major and minor crossmatches were uninterpretable due to autoagglutination in 38%/38% for SL-I and 29%/18% for SL-C crossmatches. ICS method was interpretable for 93% (major) and 98% (minor) crossmatches. After exclusion of uninterpretable SL pairings, agreement still remained poor to slight between all tests. Only 1 of 40 dogs (2.5%; 95% confidence interval: <1.0%-13.2%) had an immediate immunological transfusion reaction. CONCLUSIONS: Lack of agreement between all methodologies was noted. The high level of incompatibility predicted by SL methods despite lack of clinically relevant reactions suggests a high false incompatibility rate as compared to the ICS test. ICS testing was also able to give results more frequently in the face of autoagglutination. Further work is needed to investigate the ICS method's ability to predict clinically significant transfusion reactions.

Assessment of the physical compatibility of injectable enrofloxacin with commonly used intravenous fluids and drugs during simulated Y-port administration.

OBJECTIVE: To evaluate physical compatibility of small animal (SAE) and large animal (LAE) injectable formulations of enrofloxacin with select IV fluids and drugs. SAMPLE: 162 admixtures containing SAE or LAE with saline (0.9% NaCl) solution, lactated Ringer solution (LRS), Plasma-Lyte A (PLA), 6% hydroxyethylstarch 130/0.4 (HES), metoclopramide, or ampicillin-sulbactam. PROCEDURES: In the first of 2 simultaneously conducted experiments, admixtures containing enrofloxacin (10 mg/kg) and a volume of IV fluid that would be administered over a 20-minute period when dosed at the maintenance infusion rate (40 mL/kg/d for saline solution, LRS, and PLA and 20 mL/kg/d for HES) were created. In the second experiment, enrofloxacin (10 mg/kg) was admixed with saline solution (40 mL/kg/d) and metoclopramide (2 mg/kg/d) or ampicillin-sulbactam (30 mg/kg). In both experiments, admixture components were infused into a flask over 20 minutes assuming patient weights of 5, 10, and 20 kg. Admixtures were created by use of undiluted SAE and SAE diluted 1:1 with saline solution and undiluted LAE and LAE diluted 1:1 and 1:10 with saline solution. Admixtures were assessed for physical incompatibility at 0, 15, 30, and 60 minutes after completion of mixing. Physical incompatibility was defined as gross precipitation, cloudiness, Tyndall effect, or change in turbidity. RESULTS: Admixtures containing undiluted SAE or LAE were physically incompatible with saline solution, PLA, LRS, and HES. Because saline solution was used to dilute SAE and LAE, all admixtures containing diluted SAE or LAE were also physically incompatible. Physical compatibility of enrofloxacin with metoclopramide or ampicillin-sulbactam could not be assessed because those admixtures also contained saline solution. CONCLUSIONS AND CLINICAL RELEVANCE: Enrofloxacin was physically incompatible with all tested solutions.

Cryopreservation of feline red blood cells in liquid nitrogen using glycerol and hydroxyethyl starch.

OBJECTIVES: The objective of this study was to evaluate the techniques and short-term effects of cryopreservation of feline red blood cells (RBCs) in liquid nitrogen using glycerol or hydroxyethyl starch (HES) as a cryoprotectant. METHODS: Feline RBCs were manually mixed with either 20% glycerol or 12.5% HES and frozen for 24 h in liquid nitrogen. The samples were thawed and glycerolized samples were manually washed. Success of the freeze/thaw process was determined by recovery rate of RBCs and evaluation of morphological changes using scanning electron microscopy (SEM). A unit of canine packed RBCs was also subjected to the same methodology to evaluate the cryopreservation handling technique. RESULTS: Feline RBCs preserved with 20% glycerol had a high recovery rate (94.23 ± 1.25%) immediately after thawing. However, the majority of the cells were lost during the washing process, with a final packed cell volume of <1%. A recovery rate was unable to be assessed for samples preserved with HES owing to the high viscosity of the mixture. SEM revealed significant morphological changes after glycerol was added to the feline RBCs. Although these morphological changes were partially reversed after thawing, the majority of the RBCs were lost during the washing process. Minimal morphological changes were noted in the HES sample. Similar results were noted with the canine RBCs. CONCLUSIONS AND RELEVANCE: The described manual technique for cryopreservation using glycerol was not able to successfully preserve feline or canine RBCs. In the present study, it was difficult to make conclusions about the efficacy of HES. Further studies evaluating HES as a cryoprotectant are warranted.

Ultrasound measurements of the caudal vena cava before and after blood donation in 9 greyhound dogs.

This prospective study evaluated variation in the diameter of the caudal vena cava (DCdVC) as a marker of change in intravascular volume before and after blood donation in greyhound dogs. A preliminary study determined that the DCdVC increased with body weight. Nine greyhound blood donors had ultrasonographic images acquired of the maximum and minimum DCdVCs in transverse and sagittal orientations and sagittal aortic diameter (AoD) before and after blood donation. The collapsibility index = [(maximal mean transverse DCdVC - minimal mean transverse DCdVC)/maximal mean transverse DCdVC] and transverse DCdVC:AoD ratio were calculated for each dog. In the greyhounds, the changes in mean minimal and maximal transverse DCdVC (0.69 and 0.84 mm, respectively) and sagittal mean maximal DCdVC (0.9 mm) and collapsibility index (0.018) were significantly different (P < 0.05) before and after blood donation. While statistically significant, the magnitude of DCdVC change found in this limited number of greyhound dogs with 8% intravascular volume loss during blood donation was small. This magnitude of change is likely indistinguishable in clinical patients.

Mesures par ultrason de la veine cave caudale avant et après le don de sang chez 9 chiens Greyhound. Cette étude prospective a évalué la variation du diamètre de la veine cave caudale (DCdVC) comme marqueur du changement du volume intravasculaire avant et après le don de sang chez les chiens Greyhound. Une étude préliminaire a déterminé que le DCdVC a augmenté le poids corporel. Neuf Greyhound donneurs de sang avaient des images échographiques acquises pour les DCdVC maximum et minimum dans les orientations transversales et sagittales et le diamètre aortique sagittal (AoD) avant et après le don de sang. L'indice de collapsibilité = [(DCdVC maximal transversal moyen ­ DCdVC minimal transversal moyen)/DCdVC maximal transversal moyen] et le ratio transversal DCdVC:AoD ont été calculés pour chaque chien. Chez les Greyhounds, les changements des DCdVC minimaux et maximaux transversaux moyens (0,69 et 0,84 mm, respectivement) et le DCdVC maximal sagittal moyen (0,9 mm) et l'indice de collapsibilité (0,018) étaient significativement différents (P < 0,05) avant et après le don de sang. Même si ce changement est significatif sur le plan statistique, l'ampleur du changement DCdVC constatée dans ce nombre limité de chiens Greyhound ayant 8 % de perte de volume intravasculaire durant le don de sang était faible. Cette ampleur de changement est probablement impossible à distinguer chez les patients cliniques.(Traduit par Isabelle Vallières).

Comparison of ultrasound-guided and landmark-based techniques for central venous catheterization via the external jugular vein in healthy anesthetized dogs.

OBJECTIVE To compare time to achieve vascular access (TTVA) between an ultrasound-guided technique (UST) and landmark-based technique (LMT) for central venous catheter (CVC) placement in healthy anesthetized dogs. ANIMALS 39 purpose-bred hounds. PROCEDURES Anesthetized dogs that were hemodynamically stable following completion of a terminal surgical exercise were enrolled in the study during 2 phases, with a 45-day intermission between phases. For each dog, a UST and LMT were used for CVC placement via each external jugular vein by 2 operators (criticalist and resident). The TTVA and number of venipuncture attempts and catheter redirections were recorded for each catheterization. Placement of the CVC was confirmed by contrast fluoroscopy. After euthanasia, a gross dissection was performed during which a hematoma score was assigned to the catheter insertion site. For each phase, nonlinear least squares estimation was used for learning curve analysis of the UST. RESULTS Median TTVA, number of venipuncture attempts and catheter redirections, and hematoma score did not differ significantly between the 2 operators for either technique. Median TTVA for the UST (45 seconds) was significantly longer than that for the LMT (7 seconds). Learning curve analysis indicated that 8 and 7 UST catheterizations were required to achieve performance stability in phases 1 and 2, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the UST was comparable to the LMT for CVC placement in healthy dogs. The extra time required to perform the UST was not clinically relevant. Additional studies evaluating the UST for CVC placement in clinically ill dogs are warranted.

Relationship between intracranial pressure as measured by an epidural intracranial pressure monitoring system and optic nerve sheath diameter in healthy dogs.

OBJECTIVE: To evaluate the association between ultrasonographically measured optic nerve sheath diameter (ONSD) and acute increases in intracranial pressure (ICP) as measured by an epidural intracranial pressure monitoring system (EICPMS) in healthy dogs. ANIMALS: 6 young healthy dogs. PROCEDURES: An EICPMS connected to a pressure monitor was used to generate a continuous pressure waveform in each anesthetized dog. A 22-gauge IV catheter was inserted into the brain parenchyma through the contralateral parietal bone, and 0.5 to 2.0 mL of anticoagulated autologous blood was injected at predetermined intervals. At baseline (immediately after EICPMS placement) and following each injection, the ICP as indicated by EICPMS was recorded, and 3 ultrasonographic images of the optic nerve sheath of each eye were obtained. The ONSD was measured at maximum diameter and at 5 mm caudal to the optic disk. RESULTS: In linear models, the maximum ONSD was positively associated with increasing ICP. Specifically, the rate of maximum ONSD increase was greater for pressures ≤ 20 mm Hg above baseline (0.0534 mm/1 mm Hg ICP increase) than for pressures > 40 mm Hg above baseline (0.0087 mm/1 mm Hg ICP increase). The relationship of ICP to maximum ONSD was slightly nonlinear and best explained by comparison of fractional polynomial regression models. CONCLUSIONS AND CLINICAL RELEVANCE: ICP was positively and nonlinearly associated with increasing maximum ONSD, especially when ICP was ≤ 20 mm Hg above baseline, supporting the conclusion that ultrasonographic measurement of maximum ONSD may provide a noninvasive monitoring tool for evaluation of ICP in dogs. Further research is needed to assess the utility of these measurements in clinical patients.

Incidence of acute lung injury in dogs receiving transfusions.

OBJECTIVE: To document the existence and incidence of acute lung injury (ie, veterinary acute lung injury [VetALI] per the 2007 consensus definition) in a population of client-owned dogs receiving transfusions for various clinical reasons. DESIGN: Prospective observational study. ANIMALS: 54 client-owned dogs. PROCEDURES: Arterial blood gas analysis was performed for dogs receiving a transfusion (blood and plasma products) at 0 to 12 hours before and 24 to 48 hours after transfusion; dogs also underwent thoracic radiography 0 to 24 hours before and 24 to 48 hours after transfusion. The ratio of PaO2 to fraction of inspired oxygen (FIO2) was calculated. Dogs with posttransfusion radiographic signs of pulmonary infiltrates, a PaO2:FIO2 ratio < 300, or clinical signs of respiratory compromise were suspected of having VetALI and underwent echocardiography to exclude left-sided heart failure. The incidence of VetALI was calculated, and χ(2) tests were used to compare the incidence in study dogs with the historical reported incidence of acute respiratory distress syndrome (ARDS) in ill dogs (not receiving transfusions) and transfusion-related acute lung injury (TRALI) in humans. RESULTS: The incidence of VetALI (2/54 [3.7%]; 95% confidence interval, 0% to 8.73%) in study dogs was significantly less than the reported incidence of TRALI in humans (25%) and not significantly different from the reported incidence of ARDS in ill dogs (10%). CONCLUSIONS AND CLINICAL RELEVANCE: VetALI occurred in dogs that received transfusions at a frequency similar to that previously reported for ARDS in ill dogs that did not receive transfusions.

Optimal filling solution for silicone Foley catheter balloons.

We assessed whether saline, sterile water, or air better maintained filling volume and diameter in a veterinary silicone Foley bulb. The bulbs of 45 8-French silicone Foley catheters were inflated: 15 with 5 mL of sterile water (SW bulbs), 15 with 0.9% saline (S bulbs), and 15 with air (A bulbs). The bulbs were submerged in 30 mL of synthetic urine in a 50 mL conical tube in a 38°C water bath. Five catheters from each group were removed on days 3, 5, and 10 to measure bulb volume and diameter. On days 3 and 5, volume and diameter of SW or S bulbs were significantly greater than those of A bulbs, but were not significantly different from one another. At day 10, only 1 S bulb remained intact, 4 of the 5 SW bulbs were intact, the average volume of the SW bulbs was 2.8 mL, and the A bulbs were all deflated. We conclude that sterile water and 0.9% saline are both acceptable for Foley bulb inflation of 5 d or less, but sterile water might be preferred if bulb inflation must be maintained for more than 5 d.

Effects of general anesthesia on plasma colloid oncotic pressure in dogs.

OBJECTIVE: To determine the magnitude of the change in colloid oncotic pressure (COP) associated with general anesthesia in dogs undergoing a variety of elective procedures. DESIGN: Cohort study. ANIMALS: 50 client-owned dogs. PROCEDURES: For each dog, preanesthetic and postanesthetic PCV, plasma total solids (TS) concentration, and COP were determined. The procedures requiring anesthesia, volume of crystalloid fluids administered IV, duration of anesthesia, age, weight, and sex were recorded. RESULTS: Postanesthetic PCV (mean +/- SD, 41.8 +/- 5.4%), TS concentration (6.3 +/- 0.8 g/dL), and COP (19.4 +/- 3.6 mm Hg) were significantly decreased, compared with preanesthetic values (48.8 +/- 5.9%, 7.2 +/- 0.7 g/dL, and 24.4 +/- 4.2 mm Hg, respectively). None of the variables tested could be used to reliably predict changes in COP. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that COP in healthy dogs may decrease by 5 mm Hg on average after general anesthesia and that this decrease may not be reliably predicted by the volume of fluids administered IV during anesthesia or by the concurrent measured decrease in TS concentration.

Effects of temperature and handling conditions on lipid emulsion stability in veterinary parenteral nutrition admixtures during simulated intravenous administration.

OBJECTIVE: To determine whether lipid particle coalescence develops in veterinary parenteral nutrition (PN) admixture preparations that are kept at room temperature (23 degrees C) for > 48 hours and whether that coalescence is prevented by admixture filtration, refrigeration, or agitation. SAMPLE POPULATION: 15 bags of veterinary PN solutions. PROCEDURES: Bags of a PN admixture preparation containing a lipid emulsion were suspended and maintained under different experimental conditions (3 bags/group) for 96 hours while admixtures were dispensed to simulate IV fluid administration (rate, 16 mL/h). Bags were kept static at 4 degrees C (refrigeration); kept at 23 degrees C (room temperature) and continuously agitated; kept at room temperature and agitated for 5 minutes every 4 hours; kept static at room temperature and filtered during delivery; or kept static at room temperature (control conditions). Admixture samples were collected at 0, 24, 48, 72, and 96 hours and examined via transmission electron microscopy to determine lipid particle diameters. At 96 hours, 2 samples were collected at a location distal to the filter from each bag in that group for bacterial culture. RESULTS: Distribution of lipid particle size in the control preparations and experimentally treated preparations did not differ significantly. A visible oil layer developed in continuously agitated preparations by 72 hours. Bacterial cultures of filtered samples yielded no growth. CONCLUSIONS AND CLINICAL RELEVANCE: Data indicated that the veterinary PN admixtures kept static at 23 degrees C are suitable for use for at least 48 hours. Manipulations of PN admixtures appear unnecessary to prolong lipid particle stability, and continuous agitation may hasten lipid breakdown.