GENERAL APPROACH TO THE CRITICALLY ILL PATIENT
1. Which organ systems are most commonly dysfunctional in critically ill patients?
The respiratory system, the cardiovascular system, the internal or metabolic environment, the
central nervous system (CNS), and the gastrointestinal tract.
2. What system should be evaluated first?
The first few minutes of evaluation should address life-threatening physiologic abnormalities,
usually involving the airway, the respiratory system, and the cardiovascular system. The
evaluation should then expand to include all organ systems.
3. Which should be performed first—diagnostic maneuvers or therapeutic
maneuvers?
The management of a critically ill patient differs from the typical sequence of history and physical
examination followed by diagnostic tests and therapeutic plans. The pace of assessment and
therapy is quicker, and simultaneous evaluation and treatment are necessary to prevent
further physiologic deterioration. For example, if a patient has a tension pneumothorax, the
immediate placement of a chest tube may be lifesaving. Extra time should not be taken to
transport the patient to a monitored setting. If there are no obvious life-threatening abnormalities,
it may be appropriate to transfer the patient to the intensive care unit (ICU) for further
evaluation. Many patients are admitted to the ICU solely for continuous electrocardiogram
monitoring and more frequent nursing care.
4. How do you evaluate the respiratory system?
The most important function of the lungs is to facilitate oxygenation and ventilation. Physical
examination may reveal evidence of airway obstruction or respiratory failure. These signs include
cyanosis, tachypnea, apnea, accessory muscle use, gasping respirations, and paradoxic
respirations. Auscultation may reveal rales, rhonchi, wheezing, or asymmetric breath sounds.
5. Define paradoxic respirations and accessory muscle use. What is their
significance?
Normal breathing involves simultaneous rise and fall of the abdomen and chest wall.
n A patient with paradoxic respirations has asynchrony of abdominal and chest wall
movement. With inspiration, the chest wall rises as the abdomen falls. The opposite occurs
with exhalation.
n Accessory muscle use refers to the contraction of the sternocleidomastoid and scalene
muscles with inspiration. These patients have increased work of breathing, which is the
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amount of energy the body consumes for the work of the respiratory muscles. Most patients
use accessory muscles before they have development of paradoxic respirations. Without
support from a mechanical ventilator, patients with paradoxic respirations or increased work of
breathing will eventually have respiratory muscle fatigue, hypoxemia, and hypoventilation.
6. What supplemental tests are useful in evaluating the respiratory system?
Although all tests should be individualized to the particular clinical situation, arterial blood
gas (ABG) analysis, pulse oximetry, and chest radiography rapidly provide useful information at a
relatively low cost-benefit ratio.
7. What therapy should be considered immediately in a patient with obvious
respiratory failure?
Mechanical ventilation may be an immediate life-sustaining therapy in a patient with obvious or
impending respiratory failure. Mechanical ventilation can be carried out invasively or
noninvasively. Invasive ventilation is carried out via endotracheal intubation or
tracheotomy. Noninvasive ventilation is instituted with a nasal mask or a full face mask. Even if
the patient does not have obvious respiratory distress, supplemental oxygen should be
administered until the oxygen saturation is measured. The risk of development of oxygeninduced
hypercarbia is rare in any patient, including those with an acute exacerbation of chronic
obstructive pulmonary disease.
8. How do you evaluate the cardiovascular system?
The most important function of the cardiovascular system is the delivery of oxygen to the body’s
vital organs. The determinants of oxygen delivery are cardiac output and arterial blood oxygen
content. The blood oxygen content, in turn, is determined primarily by the hemoglobin
concentration and the oxygen saturation. It is difficult to determine the hemoglobin
concentration and the oxygen saturation by physical examination alone. Therefore the initial
evaluation of the cardiovascular system focuses on evidence of vital organ perfusion. New
technology may allow rapid assessment of hemoglobin with use of a noninvasive
spectrophotometric sensor.
9. How is vital organ perfusion assessed?
The measurement of heart rate and blood pressure is the first step. If the systolic blood pressure
is below 80 mm Hg or the mean blood pressure is below 50 mm Hg, the chances of inadequate
vital organ perfusion are greater. However, because blood pressure is determined by cardiac
output and peripheral vascular resistance, it is not possible to estimate cardiac output from blood
pressure alone. The vital organs and their method of initial evaluation are as follows:
n Lungs (see Questions 4-7)
n Skin: Assess warmth and capillary refill in all extremities.
n CNS: Assess level of consciousness and orientation.
n Heart: Measure blood pressure and heart rate, and ask for symptoms of myocardial ischemia
(e.g., chest pain).
n Kidneys: Measure urine output and creatinine level.
10. What supplemental tests are useful in the initial evaluation of the
cardiovascular system?
Electrocardiography is a potentially useful diagnostic test with a low cost-benefit ratio.
Cardiac enzyme tests, such as troponin measurement, are generally available within hours and
can suggest myocardial injury. Other tests, which may entail more risk and cost, should be
determined after the initial evaluation. These may include echocardiography, right-sided heart
catheterization, central venous pressure measurement, or coronary angiography.
11. What therapies should be considered immediately in a patient with hypotension
and evidence of inadequate vital organ function?
Fluid and vasopressor therapy can rapidly restore vital organ perfusion, depending on the cause of the
deterioration. In most patients, a fluid challenge is well tolerated, although it is possible to precipitate
heart failure and pulmonary edema in a volume-overloaded patient. Other therapies that may be
immediately lifesaving include thrombolysis or coronary angioplasty for an acute myocardial
infarction. Patients with hypotension from sepsis may benefit from early therapy involving defined
goals for blood pressure, central venous pressure, central venous oxygen saturation, and hematocrit.
12. How do you evaluate the metabolic environment?
The clinical laboratory is required for most metabolic tests. It is difficult to evaluate the metabolic
environment by physical examination alone.
13. Why are metabolic changes important to detect in a critically ill patient?
Metabolic abnormalities such as acid-base, fluid, and electrolyte disturbances are common in
critical illness. These disorders may compound the underlying illness and require specific
treatment themselves. They may also reflect the severity of the underlying disease. Metabolic
disorders such as hyperkalemia and hypoglycemia can be life threatening. Prompt testing and
treatment may reduce morbidity and improve patient outcome.
14. Which laboratory tests should be performed in the initial evaluation of the
metabolic environment?
The selected tests should have a rapid reporting time, be widely available, and be likely to produce
a change in management. Tests that fit these criteria include measurements of glucose, white
blood cell count, hemoglobin, hematocrit, electrolytes, anion gap, blood urea nitrogen,
creatinine, and pH. Elevated lactate levels suggest tissue hypoperfusion, and normal lactate
clearance is suggestive of adequate fluid resuscitation. Some of these tests may be unnecessary
in a particular patient, and supplemental testing may be useful in others.
15. How do you evaluate the CNS?
A neurologic examination is the first step in evaluating the CNS. The examination should include
assessment of mental status (i.e., level of consciousness, orientation, attention, and higher
cortical function). CNS disturbances in critical illness can be subtle. Common changes include
fluctuations in mental status, changes in the sleep-wake cycle, or abnormal behavior. The
remainder of the neurologic examination includes assessment of respiratory pattern, cranial
nerves, sensation, motor function, and reflexes. Delirium, which is common in ICU patients, can
be evaluated with the confusion assessment method (CAM-ICU).
16. What diagnostic tests and therapies should be immediately considered in a
patient with altered mental status?
Oxygen therapy may be useful in patients with altered mental status from hypoxemia. Pulse
oximetry or ABG analysis should be done to evaluate this. Intravenous dextrose may be lifesaving
in patients with hypoglycemia. Additional diagnostic tests may be indicated depending on the
clinical situation. Lumbar puncture, head computed tomographic (CT) or magnetic resonance
imaging scan, electroencephalography, and metabolic testing may be useful in directing specific
therapies. Patients with acute ischemic stroke may benefit from tissue plasminogen activator
therapy, which is most effective when administered within 90 minutes of symptom onset.
17. How do you evaluate the gastrointestinal tract?
History and abdominal and rectal examination are the first steps in an initial evaluation of the
gastrointestinal tract. Abdominal catastrophes such as bowel obstruction and bowel
perforation are common inciting events leading to multiple organ failure. In addition, abdominal
distention can reduce the compliance of the respiratory system, leading to progressive
atelectasis and hypoxemia. Further diagnostic tests such as chest radiography, abdominal
ultrasonography, plain radiography of the abdomen, or abdominal CT scan may be useful in
certain patients. For example, the finding of free air in the abdomen may lead to surgery for
correction of bowel perforation.
18. Besides the information about current organ system function, what else
should one learn about a patient in the initial evaluation?
After assessing current medical status, one should develop a sense for the physiologic reserve of
the patient, as well as the potential for further deterioration. This information may often be
gained by observing the patient’s response to initial therapeutic maneuvers. It is also important to
realize that patients may not desire cardiopulmonary resuscitation or other life-support
therapies. If the patient has completed an advance directive, such as a durable power of attorney
for health care, these guidelines should be followed or discussed further with the patient.
19. What measures can be taken to reduce patient morbidity in the ICU?
The prevention of complications in the ICU is an important patient safety issue. Each ICU should
develop strategies to prevent complications such as venous thromboembolism, nosocomial
pneumonia, and central line infections. In the last several years, a number of clinical trials have
focused on reducing morbidity and mortality among critically ill patients. Many of these
studies have evaluated common ICU problems such as acute respiratory distress syndrome,
sepsis, and postoperative hyperglycemia. Practices such as hand washing can have a major
impact on the incidence of complications.
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