Management of respiratory emergencies in small animals

Reference limits for blood gas analysis performed from coccygeal vessels of multiparous Holstein dairy cows: Effects of stage of lactation and season of sampling

Blood gas analysis is a great support to the diagnostic process of critically ill patients. Its correct application to the medicine of dairy cows depends on the availability of specific reference intervals that are still difficult to find in the literature. They may vary according to the type of blood sampled, animals' age and production stage, and climatic conditions. This study aimed at calculating the reference limits for some blood gas parameters in the blood collected from the coccygeal vessels of multiparous Holstein dairy cows. This site of sampling implies the risk of withdrawing blood of unknown origin (venous, arterial, or mixed), but has a high practical interest for the easy and quick performance and the minimal animal restraint required. Data from 379 cows were used, and reference limits were produced for pH, partial pressure of carbon dioxide (pCO2), bicarbonate concentration (HCO3), total carbon dioxide concentration (tCO2), oxygen saturation (sO2), hemoglobin (Hb), hematocrit (Hct), base excess (BE), glucose, Na, K, and ionized calcium (iCa). The effects of stage of lactation (5 to 60 vs. > 60 DIM) and season of sampling (cold vs. hot) were investigated, and specific reference limits were produced for each variable and each level of the factors whenever a significant effect was detected. The pH, sO2, K, and iCa were not influenced by season or stage of lactation. All the other blood gas parameters were significantly affected by season of sampling, and Hb, Hct, glucose, and Na were also affected by stage of lactation. Reference limits provided in this study are specific to the site of sampling (coccygeal vessels) and the animal category considered. Further studies are needed to produce reference intervals for other blood gas parameters, cow categories, and blood types.

The incidence of hypoxemia in dogs recovering from general anesthesia detected with pulse-oximetry and related risk factors

The postoperative period is critical for the development of complications, including hypoxemia. To detect hypoxemia early and provide appropriate care, continuous monitoring of saturation is necessary: pulse oximetry is an easily accessible and simple method for this purpose. However, a SpO2 cut-off value to detect hypoxemia in dogs recovering from general anesthesia is lacking in the veterinary literature. The objectives of this clinical study are to validate the room air SpO2 test (SpAT), to identify a cut-off value to discriminate hypoxemia (Phase 1), and to apply the SpAT to study the incidence of transient postoperative hypoxemia (TPH) (Phase 2) in dogs with healthy lungs recovering from general anesthesia. Phase 1: 87 dogs recovering from general anesthesia with an arterial line were included. After extubation, SpAT was performed simultaneously with arterial blood sampling. A PaO2 < 80 mmHg was considered hypoxemia. Phase 2: 654 dogs were enrolled. They underwent general anesthesia with different ventilation settings for different procedures. After extubation, dogs were classified as hypoxemic if the SpO2 was lower than the cut-off obtained in phase 1. Phase 1 showed that the SpO2 cut-off is < 95% (sensitivity 100%, specificity 97.4%; area under the curve, AUC = 0.996; 95% Confidence Interval = 0.944-1; P<0.0001). In Phase 2, 169 dogs were hypoxemic. Body Condition Score (BCS) > 3/5, dorsal recumbency, FiO2 1, absence of Positive End-Expiratory Pressure (PEEP) had a significant odds ratio to induce TPH (5.8, 1.9, 3.7, 1.7, respectively). These results showed that SpO2 < 95% indicates PaO2 < 80 mmHg in dogs and TPH occurs in up to 28% of cases. Identification of associated risks could be useful to prevent and to increase awareness for monitoring and treatment.

Assessing breathing effort by barometric whole-body plethysmography and its relationship with prognosis in client-owned cats with respiratory distress

BACKGROUND

Cats in respiratory distress have limited tolerance for manipulation, hindering clinical monitoring. Minute volume (MV) can be utilized to rate dyspnea in humans, but its relationship with respiratory distress in cats remains poorly investigated.

HYPOTHESIS

Cats with respiratory distress will show higher MV per kg body weight (MV/BW) than normal cats, and the MV/BW increase will correlate with survival.

ANIMALS

Fifty-two cats with respiratory distress from lung parenchymal disease, pleural space disease, lower airway obstruction (LAO), or upper airway obstruction were recruited since 2014.

METHODS

This is a prospective observational study. Study cats were placed in a transparent chamber, allowing clinicians to easily observe their breathing status and record ventilation using barometric whole-body plethysmography (BWBP). Ventilatory variables of the 52 cats were compared with those of 14 historic control cats. Follow-up data, including disease category, clinical outcomes, and survival, were prospectively collected.

RESULTS

Cats in respiratory distress demonstrated significantly higher MV/BW (397 mL/kg; range, 158-1240) than normal cats (269 mL/kg; range, 168-389; P < .001). Among the etiologies, cats with LAO, parenchymal, and pleural space disease exhibited higher-than-normal MV/BW trends. A cutoff value of 373 mL/kg (1.4-fold increase) indicated abnormally increased breathing efforts (sensitivity, 67%; specificity, 93%). MV/BW was independently associated with increased cardiorespiratory mortality in cats with respiratory distress (adjusted hazard ratio 1.17, 95% confidence interval [CI] 1.02-1.35; P = .03).

CONCLUSIONS AND CLINICAL IMPORTANCE

Breathing efforts in cats can be noninvasively quantified using BWBP. Measurement of MV/BW could serve as a prognostic index for monitoring cats experiencing respiratory distress.

Preliminary study evaluating the assessment of changes in pulmonary function associated with body positioning in dogs with suspected aspiration pneumonia

OBJECTIVE

To evaluate the variability in arterial blood gas (ABG) assessment of pulmonary function with different body positioning in dogs with suspected aspiration pneumonia.

KEY FINDINGS

The median differences in alveolar-arterial gradient, Pao₂ , and Paco₂ values in different recumbencies were not statistically significantly different, both within patients and across the study population. No difference was noted in ABG values in the subgroups with unilateral or bilateral disease or that were more affected on the right side versus the left side.

SIGNIFICANCE

This preliminary study provides data that can be used to calculate appropriate sample sizes for subsequent studies investigating the impact of recumbency on pulmonary function in patients with aspiration pneumonia.

A Proposed Guideline for Performance of Emergency Surgical Airways in Small Animals: Analysis of Five Unsuccessfully Managed Cannot Intubate, Cannot Oxygenate Cases

Objective—To describe three dogs and two cats diagnosed with a cannot intubate, cannot oxygenate (CICO) condition, and discuss the appropriateness and timing of emergency front-of-neck airway access (eFONA). The authors aim to increase awareness of CICO events and effective management strategies, which may result in faster airway access and improve patient outcomes. Case series summary—Three dogs and two cats could not be easily intubated resulting in the inability to deliver oxygen and contributing to their death. Emergency front-of-neck airway access was attempted in three cases, it could not be performed in one when indicated, and it was not considered in managing another. Conclusions—This is the first report of small animals suffering CICO emergencies and tracheostomy attempts without a concurrently secured airway. Cannot intubate, cannot oxygenate events and eFONA attempts were managed sub-optimally in all cases, which likely contributed to the poor outcomes. Rapid diagnosis of CICO and early eFONA using appropriate techniques has the potential to improve the management of difficult airways in small animals.

Pulmonary atelectasis in a young dog with Cor pulmonale: clinical and radiographic follow-up

Pulmonary atelectasis is a disease characterized by the collapse of the pulmonary alveoli, leading to partial or total loss of function in the affected lung, and is mostly described in older dogs. It occurs due to chronic inflammatory and obstructive processes such as pneumonia. In infants who do not feed directly from the mother, it is common to develop aspiration pneumonia due to inhalation of a milk replacer. Once aspirated, food generates an inflammatory process in the airway that alters the function of the pulmonary surfactant, increases mucus production, and causes consequent airway obstruction, which may progress to alveolar and bronchial collapse. The aim of the present study was to report a case of a 4-month-old canine with pulmonary atelectasis secondary to bronchopneumonia and the outcome of the clinical case. The patient presented with cough, exercise intolerance, tachypnea, and progressive weight loss. Thoracic radiographic examination was performed to identify displacement of the mediastinum and heart overlapping the collapsed lung, interstitial-alveolar pattern associated with atelectasis of the middle lobe of the right lung, and a diffuse interstitial bronchial pattern throughout the other lung fields. Pulmonary support treatment was administered with antibiotics, bronchodilators, mucolytics, and inhaled corticosteroids, with resolution of clinical and radiographic symptoms after 60 days of treatment. Therefore, adequate treatment of chronic bronchopneumonia is effective in resolving pulmonary atelectasis and its associated clinical complications.

A Review of High Flow Nasal Cannula Oxygen Therapy in Human and Veterinary Medicine

Respiratory distress is a common ailment in small animal medicine. Oxygen supplementation is a mainstay of initial therapy. High Flow Nasal Cannula Oxygen Therapy (HFNCOT) has become increasingly popular as a treatment modality in human medicine, and more recently in canine patients. These devices deliver high flow rates of heated and humidified oxygen at an adjustable fraction of inspired oxygen (FiO₂). This article reviews current literature in human patients on HFNCOT as well as studies that have evaluated its use in veterinary patients. A discussion of the respiratory physiology that is associated with respiratory distress, in addition to an overview of currently available oxygen supplementation modalities is provided. The physiologic benefits of HFNCOT are explained, as are technical aspects associated with its use. Recommendations on initial settings, maintenance therapy, and weaning are also described.

Association between respiratory clinical signs and respiratory localization in dogs and cats with abnormal breathing patterns

The diagnostic values of respiratory signs have been under-investigated in pets. The study aim was to explore commonly assumed associations between respiratory signs and disease localization in pets with abnormal breathing patterns (ABP). Dogs and cats with ABP presenting to three hospitals were included if investigations permitted disease localization. Hypothesized associations between respiratory signs and disease location were evaluated via mixed-effects logistic regression. Sensitivity, specificity, and positive diagnostic likelihood ratio were calculated. One-hundred and fifteen dogs and 49 cats with ABP were recruited. Confirmed associations included: inspiratory effort with extra-thoracic airway disease (odds ratio [OR], 9.1; 95% confidence interval [95% CI] 3.0-27.2); expiratory effort with intra-thoracic airway disease (OR, 6.5; 95% CI, 2.3-18.1); paradoxical breathing and attenuation of heart/lung sounds with pleural space disease (paradoxical breathing: OR, 4.5; 95% CI 1.7-12.1; sound attenuation: OR, 11.5; 95% CI 4.0-33.3); decreased nasal airflow and stertor with nasal/pharyngeal disease (nasal airflow: OR, 26.2; 95% CI 8.1-84.8; stertor: OR, 155.2; 95% CI 24.9-968.8); stridor with laryngeal or tracheal disease (laryngeal disease: OR, 39.9; 95% CI 7.6-209.0; tracheal disease: OR, 32.4; 95% CI 4.2-248.0); tracheal sensitivity with bronchial disease (OR, 3.8; 95% CI 1.5-9.6); crackles with pulmonary or bronchial disease (pulmonary disease: OR, 5.4; 95% CI 2.1-13.8; bronchial disease: OR, 3.9; 95% CI 1.6-9.8); and goose honking with tracheal disease (all dogs with goose honking had tracheal involvement). Select respiratory signs provide guidance to localize and prioritize causes of the underlying respiratory disease in pets, allowing targeted interventions in animals with ABP.

Comparison of CPAP and oxygen therapy for treatment of postoperative hypoxaemia in dogs

OBJECTIVE

To compare 5 cmH₂ O of continuous positive airway pressure with oxygen therapy in dogs recovering from general anaesthesia with low SpO₂ values. continuous positive airway pressure is more effective than oxygen therapy in restoring normoxaemia (SpO₂ ≥95%).

MATERIALS AND METHODS

Prospectively, dogs recovering from anaesthesia, with SpO₂ <95% after extubation (T0), were randomised and treated with continuous positive airway pressure (FiO₂ 0.21) or oxygen (O₂ ; FiO₂ 0.35-0.40) therapy. Dogs were monitored with SpO₂ every 15 minutes for 1 hour (T15, T30, T45, T60). Data from normoxaemic dogs (SpO₂ >95%) were used as control (CTR).

RESULTS

Of the 42 dogs enrolled, 34 completed the study. Eleven dogs were treated with O₂ , 10 with continuous positive airway pressure and 13 were CTR. The SpO₂ values at T0 were similar in the continuous positive airway pressure and O₂ groups and were lower than in the CTR group. At T15, T30, T45 and T60, the SpO₂ values in the continuous positive airway pressure group were higher than at T0; these were similar to those of the CTR group at the same time-points. In the O₂ group, SpO₂ values were significantly higher at T45 and T60 than at T0; 45.5% of dogs became normoxaemic at T45 and the remaining dogs became normoxaemic at T60. The average time to reach normoxaemia in the O₂ group (53.1±7.3 minutes) was longer than in the continuous positive airway pressure group (15.0±0.0 minutes).

CLINICAL SIGNIFICANCE

In dogs recovering from general anaesthesia with pulmonary gas exchange impairment, normoxaemia is restored more effectively and rapidly by using continuous positive airway pressure than by oxygen therapy.

Coughing in Small Animal Patients

Cough is one of the most common complaints in human medicine. In veterinary medicine cough is equally frequent and plays a significant role in an owner's perception of their pet's quality of life. In human and veterinary medicine, therapy for chronic cough is often ineffective. The complexity of the cough pathway and species differences have made it difficult to develop an effective antitussive agent for veterinary patients. The few effective antitussive agents currently available are associated with significant adverse effects. Fortunately, several promising drugs currently being studied in human clinical trials may offer options for use of novel antitussive therapies in small animal patients. This article reviews current understanding about cough pathophysiology, diagnostic strategies used to uncover underlying etiology of cough, and examines available options for controlling cough, including novel antitussive therapies used in human medicine.

Continuous positive airway pressure (CPAP) provision with a pediatric helmet for treatment of hypoxemic acute respiratory failure in dogs

OBJECTIVE

To evaluate arterial blood gas parameters and pulmonary radiography, before and after provision of continuous positive airway pressure (CPAP) via a pediatric helmet in dogs with acute hypoxemic respiratory failure.

DESIGN

Single-center, observational study conducted from 2016 to 2017.

SETTING

University teaching hospital.

ANIMALS

Seventeen dogs presenting with clinical signs compatible with respiratory failure, confirmed by arterial blood gas analyses.

INTERVENTIONS

For each animal arterial blood samples and thoracic radiographs were performed at arrival (T₀ ). Hypoxemic dogs (PaO₂  <80 mm Hg), without evidence of pneumothorax or pleural effusion, received CPAP ventilation via a pediatric Helmet for at least 1 hour. At the end of CPAP ventilation, a second arterial blood gas analysis was performed at room air (T₁ ). The F-shunt was also calculated.

MEASUREMENT AND MAIN RESULTS

Respiratory rate, heart rate and rhythm, mean blood pressure, mucosal membrane color, and rectal temperature were recorded. Tolerance to the helmet was evaluated using a predetermined scoring system. Two dogs were excluded from the study for low tolerance to the helmet. In 15 of 17 dogs, a significant difference between T₀ and T₁ was noted for PaO₂ (60.84 ± 3 mm Hg vs 80.2 ± 5.5 mm Hg), P(A-a)O₂ (52.4 ± 4.4 mm Hg vs 35.2 ± 6 mm Hg), PaO₂ /FiO₂ (289.7 ± 14.3 vs 371 ± 21), and %SO₂ (91.3 vs 98.8). In 15 of 17 dogs, the helmet was well tolerated. F-shunt significantly decreased following provision of CPAP (37%; range, 8.4-68% vs 6%; range, -5.6-64.3%).

CONCLUSION

The use of a pediatric helmet appears to be a suitable device for delivery of CPAP in dogs with hypoxemic acute respiratory failure. The device appears to be reasonably tolerated and improved oxygenation in most dogs.

Acute Respiratory Failure after Administration of Hydrogen Peroxide as an Emetic in a Cat

OBJECTIVE AND CASE SUMMARY

This case report describes a 5-year-old domestic short-haired cat that was orally administered with 4 mL of 3% hydrogen peroxide by the owner after suspecting ingestion of a foreign body by the cat. Shortly after the administration, the cat developed severe respiratory distress. Thoracic radiography showed an interstitial-to-alveolar pulmonary pattern, while echocardiography and heart injury markers ruled out a cardiac origin. Intensive management with oxygen, diuretics, bronchodilators, and sedation resulted in survival of the cat without further respiratory complications.

NEW AND UNIQUE INFORMATION PROVIDED

To the best of our knowledge, this is the first report of a lung injury and acute respiratory failure after administration of hydrogen peroxide in a cat with successful management.

Prospective pilot study for evaluation of high-flow oxygen therapy in dyspnoeic dogs: the HOT-DOG study

OBJECTIVES

To describe the use, effectiveness and tolerance of high-flow oxygen therapy in dyspnoeic dogs.

MATERIALS AND METHODS

Prospectively, dogs in acute respiratory distress admitted to an intensive care unit between January and May 2018 that failed to respond to nasal oxygen therapy and medical stabilisation after 30 minutes were transitioned to high-flow oxygen therapy. High-flow oxygen therapy, delivered an inspired oxygen fraction of 100% using an air/oxygen blender, active humidifier, single warmed tube and specific nasal cannula. Respiratory rate, pulse oximetry (SpO₂ ), heart rate and a tolerance score were assessed every 15 minutes from T₀ (under nasal oxygen) to 1 hour (T₆₀ ), and PaO₂ and PaCO₂ at T₀ and T₆₀ . Complications were recorded for each dog.

RESULTS

Eleven dogs were included. At T₆₀ , PaO₂ , flow rate and SpO₂ were significantly greater than at T₀ (171 ± 123 versus 73 ± 24 mmHg; P=0.015; 18 ±12 L/minute versus 3.2 ± 2.0 L/minute, P<0.01; 97.7 ±2.3% versus 91.6 ±7.2%, P=0.03, respectively). There was no significant difference in PaCO₂ , respiratory rate or heart rate between T₀ and T₆₀ . Tolerance was excellent, and there were no complications.

CLINICAL SIGNIFICANCE

High-flow oxygen therapy improves markers of oxygenation in dyspnoeic dogs and is an effective means to deliver oxygen with comfort and minimal complications.

Toad Intoxication in the Dog by Rhinella marina : The Clinical Syndrome and Current Treatment Recommendations

Oral exposure to the secretions of Rhinella marina (formerly Bufo marinus ) can carry a high fatality rate without early and appropriate treatment. In dogs, the clinical syndrome, which is evident almost immediately, manifests in profuse ptyalism along with gastrointestinal, respiratory, and neurologic signs. Severe cardiac arrhythmias develop less frequently. This review will cover the history, toxicology, and clinical syndrome of Rhinella marina intoxication, and will discuss the recommended therapies for stabilization.