Study Guide: Critical Care | 4S | Before Class
Critical Care
Study Guide · Class 2
Prepare to recognize neurologic emergencies, interpret endocrine and renal disturbances, identify life-threatening complications, and prioritize safe nursing actions.
Prepare to Participate
Review these concepts before class. Focus on the relationship between clinical findings, underlying pathophysiology, immediate threats, and appropriate nursing interventions. During class, use the patient’s assessment and trends to defend your clinical decisions.
What is changing? What is the immediate threat? Which findings support my concern? What should happen first? How will I evaluate the response?
Use the Clinical Judgment Cycle
Disseminated Intravascular Coagulation (DIC)
Recognize simultaneous activation of coagulation and consumption of clotting components.
Understand the Mechanism
DIC is a systemic process involving abnormal coagulation activation, microvascular thrombosis, and consumption of platelets and clotting factors. Patients may develop both thrombosis-related organ dysfunction and significant bleeding.
Interpret Laboratory Trends
Falling platelets, decreasing fibrinogen, prolonged PT, and elevated D-dimer support a consumptive coagulopathy. Trends and the clinical setting are more informative than an isolated laboratory result.
Identify Common Triggers
Sepsis, major trauma, obstetric emergencies, malignancy, and severe systemic inflammation may trigger DIC. Evaluate whether the patient has an underlying condition capable of causing widespread coagulation activation.
Prioritize Treatment and Safety
Treatment focuses on the underlying cause and supportive management. Assess active bleeding, organ perfusion, and laboratory trends. Blood products may be indicated for significant bleeding or procedures, guided by clinical findings and orders.
Status Epilepticus & Seizure Emergencies
Recognize prolonged seizure activity and prevent hypoxia, aspiration, and neurologic injury.
Recognize the Emergency
A generalized convulsive seizure lasting 5 minutes or longer, or recurrent seizures without recovery of consciousness, requires emergency treatment. Prolonged seizure activity increases the risk of respiratory and metabolic complications.
Protect Airway and Safety
Protect the patient from injury, position safely when feasible, assess breathing and oxygenation, and manage secretions appropriately. Do not restrain the patient or place objects inside the mouth.
Understand Medication Priorities
Benzodiazepines such as IV lorazepam are commonly used as initial medication treatment for established convulsive status epilepticus. Persistent seizures require prompt escalation to additional antiseizure treatment according to protocol.
Monitor for Complications
Assess oxygenation, respiratory effort, glucose, hemodynamics, seizure duration, and recovery of consciousness. Antiseizure medications may cause respiratory depression, making continued airway assessment essential.
Diabetic Ketoacidosis (DKA) vs. Hyperosmolar Hyperglycemic State (HHS)
Compare insulin deficiency, ketone production, hyperosmolality, dehydration, and treatment priorities.
Recognize DKA
DKA involves diabetes or significant hyperglycemia, ketosis, and metabolic acidosis. Patients may develop nausea, vomiting, abdominal pain, dehydration, and deep rapid respirations as compensation for metabolic acidosis.
Recognize HHS
HHS is characterized by severe hyperglycemia, marked hyperosmolality, and profound dehydration, typically without substantial ketoacidosis. Altered mental status may occur, particularly with increasing osmolality.
Understand Potassium Changes
Total body potassium is commonly depleted despite a normal or elevated initial serum potassium. Insulin shifts potassium into cells and can produce dangerous hypokalemia. Potassium must be assessed and managed before and during insulin therapy.
Individualize Treatment
Fluid replacement, electrolyte monitoring, and insulin are central components of management. The sequence and rate depend on potassium, hemodynamic status, osmolality, and whether DKA or HHS is present. Monitor for overly rapid metabolic changes.
Spinal Cord Injury & Autonomic Dysreflexia
Recognize an acute hypertensive emergency associated with spinal cord injuries at or above T6.
Recognize the Pattern
Autonomic dysreflexia may cause sudden severe hypertension, pounding headache, flushing or sweating above the injury, and pallor below the injury. Reflex bradycardia is common, although heart rate responses vary.
Identify Common Triggers
Bladder distension, urinary catheter obstruction, bowel impaction, tight clothing, and other noxious stimuli below the injury can trigger an episode. Bladder-related causes are particularly common.
Understand Immediate Measures
Sit the patient upright, lower the legs when appropriate, loosen constricting items, monitor blood pressure frequently, and seek urgent assistance. Evaluate and remove the triggering stimulus promptly.
Prevent Severe Complications
Persistent severe hypertension may require a rapid-acting prescribed antihypertensive without waiting to complete the entire search for triggers. Rectal examination or bowel care requires caution because stimulation can worsen hypertension.
Toxicology, Overdoses & Antidotes
Prioritize airway, breathing, and circulation while recognizing common toxidromes.
Recognize Opioid Toxicity
Opioid overdose may cause depressed consciousness, slow or absent respirations, and pinpoint pupils. Respiratory depression is the immediate life-threatening concern. Pupil findings may vary with the substance and clinical circumstances.
Prioritize Ventilation
Open the airway, provide assisted ventilation when indicated, and activate emergency support. Naloxone should be administered promptly for suspected opioid toxicity, but ventilation must not be delayed while preparing or awaiting its effect.
Know Antidote Relationships
Naloxone reverses opioid effects. N-acetylcysteine is used for acetaminophen toxicity. Flumazenil has limited indications in benzodiazepine toxicity because of seizure and other risks, especially with dependence or mixed overdoses.
Monitor After Initial Improvement
Reassess respiratory rate, ventilation, oxygenation, consciousness, and recurrence of toxicity. The effects of some opioids may last longer than naloxone, creating a risk of recurrent respiratory depression.
Acute Stroke: Ischemic vs. Hemorrhagic
Recognize sudden neurologic deficits and understand time-sensitive evaluation and treatment.
Recognize Acute Deficits
Sudden facial weakness, unilateral weakness, speech changes, visual disturbances, or loss of coordination require urgent stroke evaluation. Determine the last-known-well time and assess neurologic findings systematically.
Exclude Stroke Mimics
Hypoglycemia can cause neurologic deficits resembling stroke. Obtain bedside glucose promptly. Brain imaging is necessary to distinguish hemorrhage from ischemia before selecting treatments that could increase bleeding.
Understand Blood Pressure Goals
For eligible patients receiving IV thrombolysis, blood pressure generally must be below 185/110 mm Hg before treatment and maintained within recommended limits afterward. Other stroke presentations have different blood pressure targets.
Prevent Aspiration and Delays
Keep the patient NPO until an appropriate swallow screen is completed. Activate stroke protocols promptly. Reperfusion eligibility depends on timing, imaging, clinical findings, and contraindications; selected patients may qualify for additional endovascular treatment.
Acute Kidney Injury, Hyperkalemia & Dialysis
Recognize impaired renal function and distinguish cardiac stabilization from potassium redistribution and removal.
Recognize AKI
AKI may present with rising creatinine, reduced urine output, fluid overload, electrolyte disturbances, or acid-base abnormalities. Evaluate medication exposure, perfusion, obstruction, and recent clinical events.
Recognize Dangerous Hyperkalemia
Severe hyperkalemia can cause weakness and life-threatening dysrhythmias. ECG findings may include peaked T waves, conduction delays, and widening of the QRS complex. A normal ECG does not exclude dangerous hyperkalemia.
Understand Treatment Mechanisms
IV calcium stabilizes cardiac membranes but does not lower potassium. Insulin with glucose shifts potassium into cells temporarily. Potassium elimination requires appropriate renal excretion, gastrointestinal potassium binders in selected circumstances, or dialysis.
Evaluate Dialysis Needs
Renal replacement therapy may be needed for refractory hyperkalemia, severe acidosis, fluid overload, or certain toxic exposures. Monitor ECG, potassium, glucose after insulin therapy, fluid balance, and clinical response.
Thyroid Storm, Myxedema Coma & Adrenal Crisis
Differentiate endocrine emergencies using temperature, hemodynamics, neurologic findings, and clinical history.
Recognize Thyroid Storm
Thyroid storm causes severe systemic manifestations of thyrotoxicosis, including marked tachycardia, hyperthermia, agitation, and possible dysrhythmias or heart failure. Surgery, infection, or interruption of treatment may precipitate deterioration.
Understand Thyroid Storm Treatment
Supportive treatment includes temperature control, fluids as appropriate, and prescribed medications to reduce adrenergic effects and thyroid hormone synthesis and release. Thionamides, iodine given in the appropriate sequence, and corticosteroids may be used. Avoid aspirin for fever because it can increase free thyroid hormone.
Recognize Myxedema Coma
Severe hypothyroidism may cause hypothermia, bradycardia, hypoventilation, hypotension, and altered consciousness. Emergency management includes supportive care and prescribed thyroid hormone replacement, often with empiric corticosteroid coverage until adrenal insufficiency is addressed.
Recognize Adrenal Crisis
Acute adrenal insufficiency may cause hypotension, weakness, vomiting, hyponatremia, hyperkalemia in primary adrenal insufficiency, and hypoglycemia. Urgent treatment includes IV hydrocortisone and fluid resuscitation according to clinical status and protocol.
Increased Intracranial Pressure & Head Injury
Recognize neurologic deterioration and understand measures that support cerebral perfusion.
Recognize Early Changes
Changes in level of consciousness are often among the earliest and most sensitive indicators of neurologic deterioration. Trend the Glasgow Coma Scale, pupil responses, motor function, and other neurologic findings.
Recognize Late Warning Signs
Cushing’s triad consists of hypertension with widening pulse pressure, bradycardia, and irregular respirations. It is a late and ominous finding that may indicate severe intracranial hypertension and brainstem compromise.
Support Cerebral Perfusion
Prevent hypoxemia and hypotension, maintain appropriate head and neck alignment, and follow ordered positioning and ventilation targets. In many patients, elevating the head of the bed approximately 30 degrees helps facilitate cerebral venous drainage.
Escalate Neurologic Deterioration
A rapidly declining GCS, new pupillary asymmetry, abnormal respirations, or worsening motor findings requires urgent evaluation. Avoid unnecessary stimulation and reassess neurologic and hemodynamic status frequently.
Compare the Clinical Patterns
| Clinical Decision | Pattern A | Pattern B |
|---|---|---|
| Hyperglycemic emergency | DKA: ketosis and metabolic acidosis. | HHS: marked hyperosmolality and profound dehydration without substantial ketoacidosis. |
| Neurologic deterioration | Increased ICP: declining consciousness, possible pupillary changes, and late Cushing’s triad. | Acute stroke: sudden focal neurologic deficit requiring urgent imaging and evaluation. |
| Potassium treatment | Cardiac stabilization: IV calcium protects the myocardium. | Potassium reduction: intracellular shifting or removal from the body. |
| Endocrine crisis | Thyroid storm: hyperthermia, marked tachycardia, and agitation. | Myxedema coma: hypothermia, bradycardia, hypoventilation, and altered consciousness. |
| Coagulation disorder | DIC: consumption of clotting factors and platelets, often with prolonged PT and low fibrinogen. | Isolated thrombocytopenia: low platelets without necessarily having widespread consumption of clotting factors. |
| Immediate respiratory threat | Status epilepticus: airway compromise during prolonged convulsions. | Opioid overdose: respiratory depression requiring ventilation and timely naloxone. |
Build Your Explanation During Class
Identify the Evidence
“The findings that concern me most are… because together they suggest…”
Explain the Priority
“My priority is… because delaying care could lead to…”
Defend the Action
“I would first… because this action addresses…”
Evaluate the Outcome
“I would reassess… and expect improvement in…”
Approach NGN Item Formats
Highlight / SATA
Judge each finding or intervention independently. Identify whether the question asks for abnormal cues, immediate concerns, or appropriate actions.
Matrix
Apply the same classification rule across every row. Determine whether each row allows one response or multiple responses.
Bow-Tie
Connect the most likely condition with actions that address it and parameters that evaluate the response. Keep all selections clinically consistent.
Drop-down / Ordered Response
Use the clinical context to complete statements or arrange actions. Remember that some emergency interventions occur simultaneously in actual practice.