Randomized comparison between a forced air system and warm water bath for resuscitation of neonatal hypothermic calves with or without oral administration of caffeine.

BACKGROUND: Hypothermia is a cause of neonatal calf death in cold climates. Practical and effective rewarming methods are important for bovine health within affected regions. HYPOTHESIS/OBJECTIVES: To compare the rewarming rate and blood analytes (glucose, lactate, and cortisol) of calves resuscitated with forced air with warm water bath, with or without oral administration of caffeine. ANIMALS: Twenty healthy neonatal Holstein bull calves. METHODS: In this randomized, prospective study, calves born healthy and without history of dystocia were cooled to 32°C rectal temperature then thermally resuscitated using either forced air rewarming or warm water bath (40°C) with or without oral administration of caffeine. Rectal temperatures were used to quantify recovery rate. Measurements of glucose, lactate, and cortisol were recorded for every 2°C change in rectal temperature. RESULTS: Rectal temperature decline (0.03°C per minute) and total cooling time (191.0 ± 33.3 minutes) did not significantly differ among treatment groups. Calves were successfully resuscitated to 38°C by either method. Time required to euthermia using warm water was significantly faster (0.1°C per minute; 64.3 ± 17.8 minute; P < .05) than forced air (0.05°C per minute; 123.1 ± 20.0 minutes). Caffeine had no significant effect on resuscitation rate (P = .14; 95% CI, -0.002 to 0.024) in either treatment; however, caffeine was associated with reduced time to euthermia by 8.3 and 10.8 minutes, respectively. Changes in metabolic variables (glucose, lactate, and cortisol), were inversely related to rectal temperature with no statistical significance among rewarming methods. CONCLUSIONS AND CLINICAL IMPORTANCE: Although warm water submersion is faster, forced air rewarming is an effective alternative for restoration of euthermia.

Evaluation of resuscitative endovascular balloon occlusion of the aorta catheter placement and comparison to resuscitative thoracotomy with aortic clamping in cadaver dogs.

OBJECTIVE: To describe placement of an aortic occlusion catheter in aortic zone 1 (Z1) and aortic zone 3 (Z3) in dogs and to compare time to placement in these zones with and without external chest compressions (ECC). Additional evaluations of time to placement in Z1 with time for resuscitative thoracotomy with aortic clamping (RT-AC) were performed. DESIGN: Prospective ex vivo study. SETTING: University teaching hospital. ANIMALS: Ten canine cadavers. INTERVENTIONS: Ten cadaver dogs were obtained from client donation after euthanasia. Cadavers were randomized to have balloon catheter placement into the right or left femoral artery via cutdown, with or without ECC. The xiphoid was used as an external anatomical landmark for Z1, and the spinous process of the 5th lumbar vertebra was used for Z3. Balloon placement was confirmed with radiography. Time to balloon placement in Z1 and Z3 and time to RT-AC were recorded. MEASUREMENTS AND MAIN RESULTS: Median body weight was 23.5 kg (9-40 kg). Median time to Z1 placement was 6.6 minutes (4.6-12.4 minutes) with ECC and 6.9 minutes (3.3-13.1 minutes) without ECC and was not statistically different (P = 0.5). Median time to RT-AC was 1 minute (0.6-1.4 minutes), which was significantly faster than time to balloon placement in Z1 with or without ECC (P = 0.004 and P = 0.002, respectively). CONCLUSIONS: Endovascular balloon occlusion of the aorta can be achieved by cutdown with and without ECC, but RT-AC is faster. Successful balloon position in Z1 could be achieved with knowledge of external anatomical landmarks, but landmarks for Z3 need further study.

Fluid Therapy for the Emergent Small Animal Patient: Crystalloids, Colloids, and Albumin Products.

Water is essential for life. Without adequate fluid intake, normal body functioning becomes impaired and ultimately can lead to death. A fluid therapy plan should be considered for any small animal patient that has either inadequate fluid intake, excessive fluid loss, or both. A simplified approach to fluid therapy begins with an understanding of the composition of fluid and its distribution within the body. Next, consideration of electrolyte loss, acid-base disturbances, perfusion impairment, and loss of protein also becomes important when replenishing deficits by using various fluids that are commercially available to small animal practitioners.

Pathophysiology of hemorrhagic shock.

BACKGROUND: Hemorrhagic shock is a common condition that may lead to hemodynamic instability, decreased oxygen delivery, cellular hypoxia, organ damage, and ultimately death. CLINICAL IMPORTANCE: This review addresses the pathophysiology of hemorrhagic shock. Hemorrhagic shock can be rapidly fatal and is the leading cause of death in human trauma patients. Understanding the pathophysiology of hemorrhagic shock is imperative in understanding the current hemostatic and resuscitative strategies and is foundational to the development of new therapeutic options. KEY POINTS: Shock is a state of inadequate cellular energy production and can be triggered by many causes Both traumatic and non-traumatic causes of hemorrhage can lead to the development of hemorrhagic shock Prompt recognition and attenuation of hemorrhage is paramount in preventing the onset or potentiation of hemorrhagic shock Acute hemorrhage produces distinct physiological responses depending on the magnitude and rate of hemorrhage. Hemorrhagic shock may be directly related to the initial injury but may also be exacerbated and complicated by a post-traumatic coagulopathy, termed acute traumatic coagulopathy.

Calculating and selecting fluid therapy and blood product replacements for horses with acute hemorrhage.

BACKGROUND: Blood products, crystalloids, and colloid fluids are used in the medical treatment of severe hemorrhage in horses with a goal of providing sufficient blood flow and oxygen delivery to vital organs. The fluid treatments for hemorrhage will vary depending upon severity and duration and whether hemorrhage is controlled or uncontrolled. DESCRIPTION: With acute and severe controlled hemorrhage, treatment is focused on rapidly increasing perfusion pressure and blood flow to vital organs. This can most easily be accomplished in field cases by the administration of hypertonic saline. If isotonic crystalloids are used for resuscitation, the volume administered should be at least as great as the estimated blood loss. Following crystalloid resuscitation, clinical signs, HCT, and laboratory evidence of tissue hypoxia may help determine the need for a whole blood transfusion. In uncontrolled hemorrhage, crystalloid resuscitation is often more conservative and is referred to as "permissive hypotension." The goal of "permissive hypotension" would be to provide enough perfusion pressure to vital organs such that function is maintained while keeping blood pressure below the normal range in the hope that clot formation will not be disrupted. Whole blood and fresh frozen plasma in addition to aminocaproic acid are indicated in most horses with severe uncontrolled hemorrhage. SUMMARY: Blood transfusion is a life-saving treatment for severe hemorrhage in horses. No precise HCT serves as a transfusion trigger; however, an HCT < 15%, lack of appropriate clinical response, or significant improvement in plasma lactate following crystalloid resuscitation and loss of 25% or more of blood volume is suggestive of the need for whole blood transfusion. Mathematical formulas may be used to estimate the amount of blood required for transfusion following severe but controlled hemorrhage, but these are not very accurate and, in practice, transfusion volume should be approximately 40% of estimated blood loss. KEY POINTS: Modest hemorrhage, <15% of blood volume (<12 mL/kg), can be fully compensated by physiological mechanisms and generally does not require fluid or blood product therapy. More severe hemorrhage, >25% of blood volume (> 20 mL/kg), often requires crystalloid or blood product replacement, while acute loss of greater than 30% (>24 mL/kg) of blood volume may result in hemorrhagic shock requiring resuscitation treatments Uncontrolled hemorrhage is a common occurrence in equine practice, and is most commonly associated with abdominal bleeding (eg, uterine artery rupture in mares). If the hemorrhage can be controlled such as by ligation of a bleeding vessel, then initial efforts to resuscitate the horse should focus on increasing perfusion pressure and blood flow to organs as quickly as possible with crystalloids or colloids while assessing need for whole blood transfusion. While fluid therapy is being administered every effort to physically control hemorrhage should be made using ligatures, application of compression, surgical methods, and local hemostatic agents like collagen-, gelatin-, and cellulose-based products, fibrin, yunnan baiyao (YB), and synthetic glues Although some synthetic colloids have been shown to be associated with acute kidney injury in people receiving resuscitation therapy,20 this undesirable effect in horses has not been reported.

Flow rates of double-lumen over-the-wire catheters for high-volume fluid resuscitation in large animal species.

OBJECTIVES: To evaluate the maximum in vitro flow rate of 6 types of polyurethane over-the-wire double lumen catheters using both ports, for high volume fluid resuscitation in large animal species. SETTINGS: University teaching hospital. DESIGN: Prospective in vitro experimental study. INTERVENTIONS: The flow rate of both ports of 6 polyurethane double lumen over-the-wire catheters (11 and 13-Fr, 15 and 20 cm long, elliptical and tapered tip designs) and 2 types of infusion (with or without pressure bags) were tested on a factorial scheme (6 × 2) in triplicate, using commercial isotonic crystalloid (0.9% NaCl) and synthetic colloid (6% Hydroxyethyl starch, 130/0.4). MEASUREMENTS AND MAIN RESULTS: Flow rates were influenced by catheter diameter, length, tip design and presence or absence of pressure bags (P < 0.05). Mean flow rates during non-pressurized 0.9% NaCl infusion ranged from 584 mL/min (35 L/h; 11-Fr x 15 cm x tapered tip catheter) to 905 mL/min (54 L/h; 13-Fr x 15 cm x elliptical tip catheter). Mean flow rates during non-pressurized synthetic colloid infusion varied from 404 mL/min (24 L/h; 11-Fr x 15 cm x tapered tip catheter) to 724 mL/min (43 L/h; 13-Fr x 15 cm x elliptical tip catheter). Mean flow rates during pressurized infusion were 1.72 and 2.02 times greater than those obtained by gravity alone for 0.9% NaCl and synthetic colloid, respectively (P < 0.05). CONCLUSIONS: Highest in vitro flow rates were achieved when larger diameter, shorter and elliptical tip catheters were used during 0.9% NaCl infusion. Catheter diameter, tip design but not length influenced the flow rate during synthetic colloid infusion. The use of pressure bags significantly increased the flow rate of all catheters, for both solutions.

Hemorrhagic shock and hemostatic resuscitation in canine trauma.

Hemorrhage is a significant cause of death among military working dogs and in civilian canine trauma. While research specifically aimed at canine trauma is limited, many principles from human trauma resuscitation apply. Trauma with significant hemorrhage results in shock and inadequate oxygen delivery to tissues. This leads to aberrations in cellular metabolism, including anaerobic metabolism, decreased energy production, acidosis, cell swelling, and eventual cell death. Considering blood and endothelium as a single organ system, blood failure is a syndrome of endotheliopathy, coagulopathy, and platelet dysfunction. In severe cases following injury, blood failure develops and is induced by inadequate oxygen delivery in the presence of hemorrhage, tissue injury, and acute stress from trauma. Severe hemorrhagic shock is best treated with hemostatic resuscitation, wherein blood products are used to restore effective circulating volume and increase oxygen delivery to tissues without exacerbating blood failure. The principles of hemostatic resuscitation have been demonstrated in severely injured people and the authors propose an algorithm for applying this to canine patients. The use of plasma and whole blood to resuscitate severely injured canines while minimizing the use of crystalloids and colloids could prove instrumental in improving both mortality and morbidity. More work is needed to understand the canine patient that would benefit from hemostatic resuscitation, as well as to determine the optimal resuscitation strategy for these patients.

Effectiveness of intravenous fluid resuscitation in hypotensive cats: 82 cases (2012-2019).

OBJECTIVE: To evaluate the effectiveness of intravenous fluid resuscitation in hypotensive cats in an emergency room setting. Secondary objectives were to investigate changes in heart rate (HR) and body temperature (BT) in response to fluid resuscitation, and the association of these changes with patient survival. DESIGN: Retrospective study. SETTING: University teaching hospital. ANIMALS: Eighty-two cats with confirmed hypotension. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Medical records from 2012 to 2019 were searched for cats that had documented systemic arterial hypotension (blood pressure measured using a Doppler ultrasonic flow probe [DBP] < 90 mm Hg) on presentation to the emergency room. Data collected included patient characteristics and DBP, HR, and BT before and after fluid resuscitation, type and volume of fluids administered, and outcome. The median DBP before and after resuscitative fluid therapy in all cats was 65 mm Hg (range, 20-85 mm Hg) and 80 mm Hg (range, 20-128 mm Hg), respectively (P < 0.001). However, only 30 cats (37%) were classified as responders to fluid resuscitation (DBP ≥ 90 mm Hg following bolus therapy). The mean HR and median BT before resuscitative fluid therapy was 159/min and 36.7°C. Following fluid resuscitation, where measured, the mean HR and median BT was 154/min (P = 1.00) and 35.9°C (P = 1.00). No significant differences in HR and BT were identified between responders and non-responders. Cats had a low survival rate of 7%. All survivors (n = 5) were initially bradycardic (HR < 160/min), compared to only 45% of non-survivors (P = 0.4). CONCLUSIONS: Bolus fluid resuscitation effectively increases blood pressure in hypotensive cats; however, it does not result in normalization of blood pressure, HR, or BT in the majority of cases.

Clinical features and outcome of septic shock in dogs: 37 Cases (2008-2015).

OBJECTIVES: To describe patient characteristics of dogs with septic shock, investigate markers of disease severity, and assess treatment impact on outcome. DESIGN: Retrospective study. SETTING: Single center, university veterinary teaching intensive care unit. ANIMALS: Thirty-seven dogs with septic shock. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Mean number of organ dysfunction was 3.24 ± 1.0, and included cardiovascular (100%), respiratory (73%), hematologic (68%), renal (49%), and hepatic (32%) dysfunction. The gastrointestinal tract was the most common source of sepsis. Mean blood pressure prior to resuscitation was 50 ± 8 mm Hg. All dogs were given IV fluids before vasopressor therapy with a mean rate of 12.1 ± 11.0 mL/kg/h. All dogs were given antimicrobials, administered within a mean of 4.3 ± 5.7 hours after diagnosis. Dopamine or norepinephrine was administered IV, respectively in 51.3% and 37.8% of dogs, with a mean duration of hypotension of 2.6 ± 3.0 hours. Mortality rate was 81.1%. Survivors were more likely to have a feeding tube (P = 0.007) and to have gastrointestinal sepsis (P = 0.012), and less likely to have respiratory dysfunction (P < 0.001). APPLEFull scores (P = 0.014) and time to antimicrobial therapy (P = 0.047) were identified as predictors of mortality. Treatment bundles consisting of 7 interventions that may improve outcomes in people with septic shock were evaluated. Survivors received 4.1 ± 1.3 interventions, whereas nonsurvivors received 2.4 ± 1.4 (P = 0.003). CONCLUSIONS: Septic shock in dogs confers a guarded prognosis. Early antimicrobial therapy and the utilization of treatment bundles may increase survivability in dogs with septic shock. More research is warranted to investigate the impact of specific interventions on survival.

Resuscitation Strategies for the Small Animal Trauma Patient.

Traumatic injuries in small animals are a common cause for presentation to emergency departments. Severe traumatic injury results in a multitude of systemic responses, which can exacerbate initial tissue damage. Trauma resuscitation should focus on the global goals of controlling hemorrhage, improving tissue hypoperfusion, and minimizing ongoing inflammation and morbidity through the concept of "damage-control resuscitation." This approach focuses on the balanced use of blood products, hemorrhage control, and minimizing aggressive crystalloid use. Although these tenets may not be directly applicable to every veterinary patient with trauma, they provide guidance when managing the most severely injured subpopulation of these patients.

Recognition, Treatment, and Monitoring of Canine Hypovolemic Shock in First Opinion Practice in the United Kingdom.

The aim of this study was to gain a greater understanding of the detection, treatment, and monitoring of hypovolemic shock (HVS) in dogs by general practitioners in the United Kingdom (UK). An online survey was devised and distributed by email to first opinion practices in the UK. All veterinarians working in first opinion practice treating small animals were eligible to complete the survey. Most respondents (n = 164, 93%) were confident with HVS diagnosis. Isotonic crystalloid fluids were the most common fluid type for first-line treatment and administered as a 10-30 mL/kg bolus over 10-30 minutes by 57% respondents. Initial intravenous isotonic crystalloid fluid rates for HVS management ranged from maintenance fluid requirements to 90 mL/kg/hr for an undefined time period. A synthetic colloid was the most popular second-line fluid choice, typically considered after a total administered volume of 60-90 mL/kg of isotonic crystalloid fluids. Only 72 respondents (40.7%) were able to measure blood lactate in-house, which was used routinely by 36 respondents (20.3%) for initial treatment decision making. Respondents treating HVS most frequently were more likely to use lactate for initial decision making (P = .008). This study highlighted variabilities in the initial approach, fluid management strategies and monitoring instituted by UK general practitioners when faced with canine patients in HVS. This suggests that there is a discrepancy in what is determined to be the most optimal diagnostic and treatment plan for canine HVS patients.

Placement of a balloon for resuscitative endovascular balloon occlusion of the aorta without fluoroscopic guidance in canine cadavers.

OBJECTIVE: To determine whether a balloon for resuscitative endovascular balloon occlusion of the aorta (REBOA) could be accurately placed in the descending aorta between the left subclavian and celiac arteries (zone I) by using external anatomic landmarks in dogs. STUDY DESIGN: Cadaver study. SAMPLE POPULATION: Fifteen canine cadavers of 3 weight categories (10-20, 20-30, and ≥ 30 kg). METHODS: Percutaneous catheterization of the femoral artery was attempted under ultrasonographic guidance; when unsuccessful, an arterial cutdown was performed to place an introducer sheath. Distance was measured between the introducer sheath and the target region, located ventral to the epaxial muscles at the level of the 12th thoracic vertebra. The balloon was advanced the measured distance, and placement was confirmed with fluoroscopy. The volume of iohexol solution required to inflate balloons was recorded. Histopathology was performed on the aortas of the first 5 dogs. RESULTS: Three catheters were placed under ultrasonographic guidance. Balloons were successfully placed into zone I in 15 of 15 cadavers. Balloons were inflated with a median 0.4 mL/kg (range, 0.21-0.67) of iohexol solution. Minor changes were identified in 2 of 5 dogs examined with histopathology (linear defects in 1 dog, small focal dissection in the other). CONCLUSION: A balloon for REBOA was consistently placed in the target zone I without fluoroscopic guidance. CLINICAL SIGNIFICANCE: Fluoroscopy may not be required for zone I REBOA in dogs. Additional studies are warranted to evaluate the feasibility of REBOA in clinical dogs with hemoperitoneum.

Location is everything: The hemodynamic effects of REBOA in Zone 1 versus Zone 3 of the aorta.

OBJECTIVES: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an emerging technology to augment proximal blood pressure during the resuscitation of patients with noncompressible torso hemorrhage. Currently, placement choice, supraceliac (Zone 1) versus infrarenal (Zone 3) aorta, depends on injury patterns, but remains a highly debated topic. We sought to compare the proximal hemodynamic support provided by Zone 1 versus Zone 3 REBOA placement and the degree of hemodynamic instability upon reperfusion following intervention. METHODS: Eighteen anesthetized swine underwent controlled hemorrhage of 25% total blood volume, followed by 45 minutes of Zone 1 REBOA, Zone 3 REBOA, or no intervention (control). They were then resuscitated with shed blood, aortic balloons were deflated, and 5 hours of critical care ensued prior to euthanasia. Physiologic parameters were recorded continuously, and blood was drawn for analysis at specified intervals. Significance was defined as p < 0.05. RESULTS: There were no significant differences between groups at baseline or during the initial 30 minutes of hemorrhage. During the intervention period, average proximal MAP was significantly greater in Zone 1 animals when compared with Zone 3 animals (127.9 ± 1.3 vs. 53.4 ± 1.1 mm Hg) and greater in Zone 3 animals when compared with control animals (42.9 ± 0.9 mm Hg). Lactate concentrations were significantly higher in Zone 1 animals (9.6 ± 0.4 mmol/L) when compared with Zone 3 animals (5.1 ± 0.3 mmol/L) and control animals (4.2 ± 0.8 mmol/L). CONCLUSIONS: In our swine model of hemorrhagic shock, Zone 3 REBOA provided minimal proximal hemodynamic support when compared with Zone 1 REBOA, albeit with less ischemic burden and instability upon reperfusion. In cases of impending hemodynamic collapse, Zone 1 REBOA placement may be more efficacious regardless of injury pattern, whereas Zone 3 should be reserved only for relatively stable patients with ongoing distal hemorrhage.

Systemic and Local Management of Burn Wounds.

Management of severe burn injury (SBI) requires prompt, complex, and aggressive care. Despite major advances in the management of SBI-including patient-targeted resuscitation, management of inhalation injuries, specific nutritional support, enhanced wound therapy, and infection control-the consequences of SBI often result in complex, multiorgan metabolic changes. Consensus guidelines and clinical evidence regarding specific management of small animal burn patients are lacking. This article aims to review updated therapeutic consideration for the systemic and local management of SBI that are proven effective to optimize outcomes in human burn patients and may translate to small animal patients.

Cardiac arrest in an American Cocker Spaniel during a deep ear flush procedure.

CASE DESCRIPTION A 14-year-old spayed female American Cocker Spaniel with bilateral otitis media and no evidence of cardiovascular instability was anesthetized to allow performance of a deep ear flush. CLINICAL FINDINGS Otoscopic examination of the left ear revealed evidence of chronic inflammation; the ear was flushed with sterile saline (0.9% NaCl) solution. Examination of the right ear revealed more severe chronic inflammation than in the left ear, including a ruptured tympanum (timing of rupture unknown). The right ear was flushed with sterile saline solution, and several drops of otic medication were instilled. During infusion of saline solution, the ECG revealed a rapid decrease in heart rate until no more electrical activity was noted. Pulse also ceased to be detectable via pulse oximetry and femoral artery palpation. TREATMENT AND OUTCOME Isoflurane was discontinued immediately after recognition of cardiac arrest. Shortly after, atropine (0.04 mg/kg [0.02 mg/lb]) and epinephrine (0.3 mg/kg [0.14 mg/lb]) were administered IV, chest compressions and ventilation were performed for 2 to 3 minutes, and 3 boluses (each 5 mL/kg) of lactated Ringer solution were administered IV. The dog was extubated 8 minutes after anesthesia was discontinued, and its recovery was monitored for the next 5 hours. No further incidents of cardiac arrest occurred after recovery from anesthesia. CLINICAL RELEVANCE This case represented a rarely documented potential complication associated with otic manipulation in a dog: cardiac arrest secondary to stimulation of the auricular branch of the vagus nerve. Veterinarians should be prepared for and warn clients of this possibility prior to otic flushing.

Managing Fluid and Electrolyte Disorders in Kidney Disease.

Because of the role of the kidneys in maintaining homeostasis in the body, kidney disease leads to derangements of fluid, electrolyte, and acid-base balance. The most effective therapy of a uremic crisis is careful management of fluid balance, which involves thoughtful assessment of hydration, a fluid treatment plan personalized for the specific patient, and repeated and frequent reassessment of fluid and electrolyte balance. Disorders of sodium, chloride, potassium, calcium, and phosphorus are commonly encountered in kidney disease and some may be life-threatening. Treatment of metabolic acidosis and nutritional support is frequently needed.

Fluid Management in Patients with Trauma: Restrictive Versus Liberal Approach.

Massive hemorrhage remains a major cause of traumatic deaths. The ideal fluid resuscitative strategy is much debated. Research has provided inconsistent results regarding which fluid strategy is ideal; the optimum fluid type, timing, and volume remains elusive. Aggressive large-volume resuscitation has been the mainstay based on controlled hemorrhage animal models. For uncontrolled hemorrhagic shock, liberal fluid resuscitative strategies exacerbate the lethal triad, invoke resuscitative injury, and increase mortality while more restrictive fluid strategies tend to ameliorate trauma-induced coagulopathy and favor a greater chance of survival. This article discusses the current evidence regarding liberal and restrictive fluid strategies for trauma.

Alternative Access Routes for Fluid Resuscitation.

Fluid resuscitation in small animals is important in emergency situations and is utilized by every veterinary practice. Peripherally inserted intravenous catheters are an effective way of giving fluids to a veterinary patient. If an intravenous catheter is not obtainable, there are multiple other ways to administer fluids to a patient including dorsal pedal catheters, intraosseous catheters, central venous catheters, peripherally inserted central catheters, nasogastric tubes, nasoesophageal tubes and subcutaneous administration of fluids. This article will discuss the advantages and disadvantages of each way of administration.