Hospitalized Patients

Critical Care

• Veterinary critical care is a specialized service provided to pets with severe injuries, trauma, or illness

• Patients needing critical care may be suffering from severe infection, kidney, heart, liver, or respiratory failure

• Animal intensive care units provide advanced monitoring and treatment for these critically ill animals in a caring and compassionate environment

• Critically ill patients may sometimes be difficult to identify initially, as some animals can be stoic and may not show signs of illness, pain, or weakness until their condition is quite advanced

• Rapid identification and stabilization are essential for ensuring positive outcomes

• Key signs affecting the respiratory, cardiovascular, and neurologic systems are readily identifiable during the initial assessment

• Physical markers of critical illness can include changes in mentation, heart rate, respiratory rate, temperature, capillary refill time, and mucous membrane color

• Patients requiring immediate triage and direct transport to the treatment area are those showing significant abnormalities in their respiratory, cardiovascular, and central nervous systems

  • Other critical illnesses seen can include seizures, signs of shock, excessive bleeding, trauma, prolapsed organs, snake bites, signs of anemia

  • Patients presenting laterally recumbent with a dull to nonresponsive mentation are considered the most critical and require immediate intervention

• Respiratory distress: Often involves abdominal respiratory effort and presenting with the head and neck stretched out

• When triaging a respiratory patient, specific questions to as yourself include assessing the respiratory rate, pattern/effort, if effort is on inspiration or expiration, patient position, presence of cyanosis, auscultation findings, SpO2, and temperament/mentation

• Upper airway obstruction is associated with inspiratory dyspnea and externally audible noise, while lower airway obstruction tens to be associated with expiratory dyspnea and wheezing

• Cardiovascular Issues: Patients may present collapsed with dull to obtunded mentation, pale gums, and poor, thready pulses

• Neurologic Signs: Patients can present with dull mentation or actively seizing

• Immediate nursing care steps often performed concurrently with the initial assessment and stabilization may include:

  • Evaluating and securing the patient’s airway, including intubation if needed

  • Providing supplemental oxygen therapy, which is an immediate step for patients in respiratory distress as it increases the fraction of inspired oxygen

  • Obtaining vascular access for fluid or drug administration

  • Initiating active cooling therapy if the patient is hyperthermic, especially in cases of upper airway obstruction or heat stress

  • Providing sedation or anxiolytic therapy if needed to helping keep the patient calm

  • Thoracocentesis may be included in initial stabilization if severe respiratory distress is secondary to pleural space disease like pneumothorax or pleural effusion

• Upper airway issues in veterinary critical care primarily involve mechanical or functional obstruction of the pharynx, larynx, or trachea

• Specific conditions can cause obstruction in the upper respiratory tract:

  • Naso-oropharyngeal disorders such as polyps, masses, and foreign bodies

  • Severe head trauma resulting in fractures and associated swelling or hemorrhage

  • Laryngeal disorders, including laryngeal paralysis, laryngeal collapse, masses

    • Laryngeal paralysis is more commonly observed in aging Labrador retrievers and other large and giant breeds, as well as hypothyroid dogs

• Tracheal diseases such as tracheal collapse, foreign bodies, stenosis, strictures, tears, or masses

  • Tracheal collapse is frequently seen in small breed dogs, especially Yorkshire terriers, Pomeranians, Maltese, and toy poodles

• Brachycephalic airway disease, a combination of primary and secondary anatomical abnormalities including stenotic nares, elongated soft palate, everted laryngeal saccules, and potentially laryngeal edema/collapse and hypoplastic trachea

  • Nasal disorders typically do not cause dyspnea because affected animals can breathe through their mouths

• Characteristic signs of upper airway obstruction include inspiratory distress and an externally audible noise like stertor or stridor

• Dogs with upper airway obstruction often have noisy breathing that worsens with exercise or heat

• In tracheal collapse, the cough can be intermittent or persistent, productive or dry

  • Severe tracheal collapse or tracheal malformation can cause intermittent respiratory distress

• Initial Stabilization:

  • Managing patients with upper airway issues requires prompt initial stabilization to provide time for diagnosis and further therapy

• Oxygen Supplementation:

  • This is an immediate step

  • Face mask

  • Flow-by oxygen, or nasal oxygen cannula

  • Flow-by is considered an inefficient technique

• The term dyspnea refers to the experience of distress secondary to respiratory disease

• Like pain, its presence is inferred from facial expressions and behavioral signs of distress

• Tachypnea, or rapid breathing, is not the same as dyspnea, or difficulty breathing

• Airway management: Ensuring a patient airway is essential

• This may involve intubation or tracheostomy if needed, especially if oral intubation is not possible

• Sedation: Anxiolytic or sedative analgesic drugs are often necessary to keep patients calm, reduce the stress associated with increased work of breathing, and allow for nursing care and procedures

• Options include butorphanol, acepromazine, or dexmedetomidine; butorphanol is recommended for cats

  • Patients require close monitoring for oversedation, which could lead to airway occlusion

• Cooling measures: Patients with upper airway obstruction, particularly brachycephalic breeds, are prone to hyperthermia

• Respiratory acidosis in dogs occurs when the body can’t effectibely remove carbon dioxide from the blood leading to a buildup of acid in the body

• This is often due to decreased breathing rate or impaired lung function, resulting in elevated CO2 levels

• The condition is characterized by decreased blood pH and increased PCO2, with the body attempting to compensate by increasing bicarbonate levels

• Blood Gas Analysis: This test measures the pH, PCO2, and bicarbonate levels in the blood, which can confirm the diagnosis and severity of the acidosis

• Imaging: Chest X-rays or other imaging techniques may be used to identify the cause of the respiratory problem

• Providing Adequate Ventilation: This may involve using oxygen therapy, intubation or mechanical ventilation

• Fluid Therapy: IV fluids may be used to help maintain blood pressure and electrolyte balance

• Respiratory Alkalosis: In contrast, respiratory alkalosis occurs when the body’s blood pH becomes too alkaline due to a deficiency of CO2 in the blood

• This happens when the lungs remove too much CO2 from the body, often due to hyperventilation or other respiratoyr conditions

• Causes of Respiratory Alkalosis in Dogs: Several factors can cause respiratory alkalosis in dogs, including

  • Hyperventilation: Dogs may hyperventilate due to pain, anxiety, fever or other conditions that stimulate rapid breathing

  • Pulmonary Disease: Conditions like pulmonary fibrosis or right to left shunt can impair gas exchange and lead to hyperventilation as the dog tries to compensate

  • Sever Anemia: Severe anemia can also lead to hyperventilation as the dog tries to get more oxygen to the tissues

• Corticosteroids: Anti-inflammatory doses of corticosteroids can be considered to reduce edema in the upper airway soft tissue caused by breathing against an obstruction

• Handling: Careful and stress-reducing handling is crucial for these patients

• Diagnostics should generally be pursued once the patient is stable

• Upper Airway Examination: This is performed under sedation after preoxygenation

• Laryngeal Function Assessment: If laryngeal paralysis is suspected, anesthesia levels should be minimized to best preserve laryngeal function

• Definitive management depends heavily on the specific underlying diagnosis

• Brachycephalic Airway Disease: Surgical palliation is a common treatment

• Laryngeal Paralysis: Confirmed by visual examination of laryngeal function

• Tracheal Collapse: Initial management is often medical, although surgical intervention may be more beneficial for significant obstruction

  • Theophylline may help with bronchomalacia and collapse by improving mucocillary clearance and expiratory airflow

  • Surgical options include placing external tracheal rings or intralumenal tracheal stents

• Close monitoring is essential for patients with respiratory distress

• End-tidal CO2 monitory can help detect hypercarbia, which may indicate inadequate ventilation

• HFOT is not suitable for all patients with upper airway issues, especially those with nasal masses, facial trauma, or conditions where increased intracranial pressure in a concern

• Common Heart Diseases Leading to CHF:

  • Degenerative Mitral Valve Disease

  • Dilated Cardiomyopathy is characterized by the weakening and thinning of the heart muscle, particularly the left ventricle, leading to chamber dilation and decreased contractility

  • Hypertrophic Cardiomyopathy is the most common heart disease of cats and is characterized by primary concentric left ventricular hypertrophy

  • Pericardial Disease, commonly involving accumulation of fluid in the sac around the heart, which can lead to cardiac tamponade

  • Arrhythmias

  • Other causes mentioned include cardiac neoplasia, pulmonary hypertension, infective endocarditis, and some congenital defects

• Classification/Staging

• The severity of degenerative valve disease is often classified into stages

  • Stage A: Dogs at high risk of developing heart disease

  • Stage B: Dogs with heart disease but no clinical signs

  • B1: Signs of heart disease but no structural changes

  • B2: Signs of heart disease with structural changes

  • Stage C: Dogs with clinical signs secondary to heart disease, predominantly in CHF

  • Stage D: Dogs in refractory CHF, meaning edema recurs despite standard therapy

• Signs of heart disease can vary, but those with CHF often show:

  • Increased respiratory rate, especially when sleeping

  • Increased respiratory effort while at rest

  • Coughing

  • Lethargy or decreased activity tolerance

  • Exercise intolerance

• Fluid accumulation: Pulmonary edema with left-sided CHF

  • Pleural effusion or ascites, often associated with right-sided or biventricular failure

  • Signs of right heart failure, like ascites and pleural effusion, can predominate with pericardial effusion

• In severe cases, patients may present collapsed with dull mentation, pale gums, and poor pulses

• A wildly jagged baseline on ECG may indicate atrial fibrillation

• Electrical alternans may be seen on ECG with large pericardial effusions

• Left sided CHF: Fluid backs up into the lungs or pleural space

• Clinical Signs:

  • Coughing

  • Hypoxia, dyspnea, tachypnea, cyanosis, abnormal respiratory sounds

• Right sided CHF: Fluid in abdominal and thoracic cavities

• Clinical Signs:

  • Edema, Jugular distention, abdominal distention, hepatomegaly, pleaural and pericardial effusions

• Nursing Care: Are critical cases that require oxygen, diuretics and removal of any effusion present

• Treatment is often divided into acute and chronic phases, aiming to control congestion and support cardiac output

• Acute Phase: Minimize stress: A hands off approach is best for dyspneic patients to avoid increasing oxygen demand

• Diuretics: Potent loop diuretics, such as furosemide, are the mainstay for treating pulmonary edema

• Pimobendane: It acts as an indicator, increasing contractility and causing vasodilation, which helps support the failing heart and decrease in left atrial pressure

• Other short-term options: Dobutamine can be used for patients with poor forward output or those failing to respond to routine management

• Beta-blockers: Should never be administered to patients with acute CHF due to potential negative effects on contractility and output

• Chronic Phase:

  • Medications: Typically include oral furosemide or torsemide, pimobendane, and an ACE inhibitor

• Arrythmia Management: Drugs like digoxin, diltiazem, atenolol, carvedilol, sotalol, procainamide, and mexiletine may be used depending on the type of arrythmia

• Anti-clotting medication: Clopidogrel is often used in cats with enlarged left hearts or a history of arterial thromboembolism to reduce the risk of blood clots

• Other medications: Sildenafil may be used for pulmonary hypertension

  • Surgery: Surgical repair of the mitral valve is an option

  • Pericardial Effusion Treatment: Primarily involves mechanical drainage using a catheter

• Pericardiocentesis: Pericardial effusion is defined as the accumulation of fluid within the pericardial space

• Normal heart rate is 60-160 in dogs and 140-210 in cats

• The P wave indicated atrial depolarization

• The QRS complex indicates ventricular depolarization

• The T wave indicates ventricular repolarization

• This tracing demonstrates a normal positive P wave, a negative Q wave, a positive R wave, and no distinct S wave in the lead

• Sinus Bradycardia: This is a regular rhythm with a P wave for every QRS complex

• This rhythm is usually slow

• This can result in slowed conduction, occasional failure of conduction, or persistent failure of conduction

• Sinus tachycardia: A regular rhythm with a P wave for every QRS complex

• AF is the most common persistent arrhythmia seen in small animals

• What is Blood Pressure?

  • Blood pressure is the force exerted by blood on the walls of the arteries as it flows through them

  • Systemic arterial blood pressure is generated by the pumping action of the heart, the circulating arterial blood volume

• Cardiac output itself is calculated as stroke volume multiplied by the heart rate

• There are two points in the cardiac cycle where the blood pressure is measured

  • Systolic blood pressure: the highest pressure in the artery during systole

  • Diastolic blood pressure: The lowest pressure in the artery during diastole

• Normal Blood Pressure Values in Adult Dogs and Cats:

  • Dogs: SAP 90 to 140 mmHg, DAP: 50-80 mmHg, MAP: 60 to 100mmHg

  • Cats: SAP 80 to 140 mmHg, DAP: 55 to 75 mmHg, MAP: 60 to 100mmHg

• Measuring Blood Pressure:

  • Arterial blood pressure can be measured using two main methods:

    • Direct Arterial Blood Pressure: Considered the gold standard for accuracy

      • Requires placing an arterial catheter connected to pressure transducer.

      • Allows for continuous monitoring of SAP, DAP, and MAP.

      • Indications for use often include critically ill patients such as those in shock, congestive heart failure receiving vasodilators, requiring vasopressors or mechanical ventilation, receiving medication for severe hypertension, or having a high anesthetic risk.

    • Indirect Arterial Blood Pressure: The most frequently used technique in clinical practice

      • Relies on noninvasive detection of blood flow or vessel wall movement

      • Provides intermittent measurements

• Advantages of Doppler include ease of use, affordability, and suitability for patients with significant hypotension or cardiac arrhythmias

  • Accuracy can be affected by cuff size

• Oscillometric Measurement: Uses a transducer to detect vibrations in arteries

  • Advantages are that is is more automated, requires less skill

• For both Doppler and Oscillometric methods, using the correct cuff size and obtaining multiple consecutive readings are crucial for accuracy

• Hypotension: Defined as SAP <90 mmHg and MAP < 60 mmHg

• Indicates decreased cardiac output

• Thoracic radiographs are a readily available modality for the cardiovascular workup

• X-rays can also help rule out other causes for a pet’s symptoms

• A common way to measure heart size on an X-ray is called the vertebral heart size

• This compares the heart’s size to the bones of the spine

• A general VHS greater than 11.5 can even be used in some cases to classify disease severity if echocardiography isn’t done

• Checking the lungs and blood vessels: X-rays are crucial for looking at the lungs, which are closely connected to the heart

• When the heart isn’t pumping effectively, fluid can back up into the lungs or the chest cavity

• Diabetic Ketoacidosis is a very serious and life-threatening complication of diabetes mellitus that requires immediate medical attention

• Diabetes Problem: Normally, insulin acts like a key to let glucose, which is the body’s main fuel, into cells from the bloodstream

• Body Burns Fat for Fuel: To try and get energy, the body starts breaking down fat quickly

• Ketones are produced: When fat is broken down rapidly, the liver produces substances called ketone bodies

• Blood becomes acidic: Ketone bodies are acidic

• Essentially, DKA is a state where the body, lacking insulin, starves for glucose, frantically burns fat for energy, produces acidic ketones, and becomes severely dehydrated with dangerous electrolyte imbalances