Physical Examination

Chapter 1 Physical Examination



Timothy B. Hackett, DVM, MS, DACVECC



KEY POINTS



• Hands-on assessment of critically ill patients is essential to detect life-threatening changes in their condition.

• Clinicians should use their eyes, ears, hands, and nose to evaluate the critically ill patient before jumping to blood tests, electrodiagnostic techniques, or imaging.

• Physiologic variables related to oxygen delivery take precedence in evaluating the critically ill patient.

• Clinicians and other personnel should note and record both subjective and objective physical examination parameters as often as necessary, taking into consideration the patient’s current problems and anticipated complications.


INTRODUCTION


Physical examination, or more correctly, serial physical examination, is the core of critical care medicine. Sometimes it seems that all intensivists do is monitor, record, and interpret readily available physiologic variables. Although this may be true, it is important to remember why. The goal is to detect problems with organ function before organ dysfunction becomes organ failure.


Technology helps to identify life-threatening problems. Arterial blood gas machines, oscillometric blood pressure monitors, pulse oximeters, ultrasound machines, and portable coagulation analyzers are just a few of the technologic advances that have found their way into 24-hour emergency and critical care veterinary practices. Their appropriate use has improved our ability to provide the best care to our patients. However, with reliance on technology, clinicians may have forgotten some of the “art” of the physical examination. To date there is no readily available technology that can measure adequacy of perfusion or degree of hydration. Although measurement of parameters such as blood pressure provides vital information, it can be interpreted only in light of the physical examination. When a clinician reaches for an ultrasonography probe or electrocardiograph (ECG) before touching the patient with hands and stethoscope, something has been lost.


The physical examination of the critically ill patient is approached much in the same way as for the emergency patient. With focus on the efficacy of oxygen delivery, the first priority is assessing the respiratory and cardiac systems. The ABCs (airway, breathing, and circulation) of resuscitation provide a simple systematic approach to the primary survey.



AIRWAY AND BREATHING


Patients adapt respirations to minimize the work of breathing. Animals with upper airway obstruction, dynamic airway collapse, bronchitis, or other obstructions to airflow will breathe slowly and deeply. With upper airway and extrathoracic obstructions, the effort will be on inspiration. With obstruction or collapse of the intrathoracic small airways, the effort will be on expiration. By decreasing the force of respiration, this so-called obstructive breathing pattern will favor maximal flow through narrowed airways with minimal energy expenditure. The effect of respiratory rate and depth on obstructive breathing can be experienced by trying to breathe through a straw.


Animals with pleural space disease, atelectasis, or pulmonary fibrosis will adopt what is known as a restrictive breathing pattern. By minimizing the change in volume while increasing the respiratory rate, they can maintain alveolar minute ventilation despite decreased pulmonary compliance (see Chapter 9, Tachypnea and Hypoxemia).



CIRCULATION


Alveolar oxygenation is the first essential step in providing adequate oxygen delivery to the tissues. A normal cardiovascular system is then necessary to carry the blood to the lungs for oxygen loading and back to the body. Physical assessment of the circulatory system relies on palpation and observation of venous distention, palpation of the arterial pulse (for synchrony, quality, and heart rate), evaluation of mucous membrane color and capillary refill, and auscultation of the heart and lungs. Inadequate global perfusion is considered an indicator of circulatory shock and is a clinical diagnosis made from physical examination alone.



Heart Rate


A normal heart rate indicates that at least one component of cardiac output is normal. We expect a heart rate of 70 to 120 beats/min in small dogs, 60 to 120 beats/min in large dogs, and 120 to 200 beats/min in cats.


Bradycardia results in decreased cardiac output and subsequent poor perfusion; cats often develop bradycardia (<120 beats/min) in shock, and this can be associated with imminent cardiac arrest. Bradycardia is an unusual finding in a critically ill patient and can result from electrolyte imbalances (hyperkalemia), neurologic disease (increased intracranial pressure), conduction disturbances (atrioventricular block, sick sinus syndrome), or overdose of analgesic or anesthetic drugs. An ECG is indicated for full assessment of bradycardia.


Tachycardia (dogs >180 beats/min, cats >220 beats/min) is the body’s response to decreased blood volume, pain, anxiety, and hypoxemia. Increasing heart rate will temporarily increase cardiac output and oxygen delivery. However, there is some limitation to this response. When the heart rate becomes too fast, diastolic filling is compromised and stroke volume suffers. Sinus tachycardia often results from circulatory shock or pain; tachycardia that is irregular or associated with pulse deficits usually indicates an arrhythmia, and an ECG is indicated.



Mucous Membrane Color


Evaluation of mucous membrane color is subjective but can give an experienced clinician a great deal of important information. Pale or white mucous membranes are indicative of anemia or vasoconstrictive shock. Red mucous membranes suggest vasodilation as seen in systemic inflammatory states and hyperthermia. Cyanotic gums indicate a normal packed cell volume (cyanosis will not be clinically evident without adequate hemoglobin) but severe hypoxemia. A yellow hue indicates increased serum bilirubin (from hepatic disease or hemolysis), and a brown color of the gums can be seen with methemoglobinemia. During examination of the gums, petechiation or bleeding should be noted. Thrombocytopenia is an early finding in disseminated intravascular coagulation. Petechiae and bruising are clinical signs of platelet deficiency or dysfunction.



Capillary Refill Time


Evaluation of capillary refill time (CRT) is also subject to interpretation. You may even notice a normal CRT in a recently deceased patient. However, used in conjunction with pulse quality, respiratory effort, heart rate, and gum color, the CRT can help assess a patient’s blood volume and peripheral perfusion, and give an insight into causes of a patient’s shock. Normal CRT is 1 to 2 seconds. This is consistent with a normal blood volume and perfusion. A CRT longer than 2 seconds is a subjective sign of poor perfusion or peripheral vasoconstriction. Peripheral vasoconstriction is an appropriate response to low circulating blood volume and reduced oxygen delivery to vital tissues. Patients with hypovolemic and cardiogenic shock should be expected to have peripheral vasoconstriction. Peripheral vasoconstriction is also commonly associated with cool extremities, assessed by feeling the distal limbs. A CRT less than 1 second is indicative of a hyperdynamic state and vasodilation (as are bright red mucous membranes). Hyperdynamic states can be associated with systemic inflammation, heat stroke, distributive shock, and hyperthermia.


Venous distention can be a sign of volume overload or right-sided congestive heart failure. Palpation of the jugular vein may demonstrate distention, although it may be easier to appreciate by clipping a small patch of hair over the lateral saphenous vein. With the patient in lateral recumbency, if the lateral saphenous vein in the upper limb appears distended (as if the vessel is being held off), slowly raise the rear leg above the level of the heart. If the vein remains distended, the patient likely has an elevated central venous pressure, and volume overload or diseases causing right-sided congestive heart failure (dilated cardiomyopathy, tricuspid insufficiency, pericardial effusion) should be considered. A patient with pale mucous membranes from vasoconstriction in response to hypovolemia would not be expected to have venous distention. In comparison, cardiogenic shock is more likely to cause pale mucous membranes and increased venous distention.

Related posts:

  1. Hypotension
  2. Endotracheal Intubation
  3. Thoracentesis
  4. Pulmonary Contusions and Hemorrhage

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Sep 10, 2016 | Posted by in SMALL ANIMAL | Comments Off on Physical Examination

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