10.1 Systematic Primary and Secondary Patient Assessment (ABCDE Approach)

Systematic Primary and Secondary Patient Assessment (ABCDE Approach)

Clinical Core: Acute clinical deterioration requires a disciplined, rapid, and structured assessment framework. The ABCDE (Airway, Breathing, Circulation, Disability, Exposure) approach serves as the gold-standard systematic algorithm across emergency departments, medical-surgical wards, and intensive care units. Its foundational principle is hierarchical: treat the most life-threatening physiological abnormality first before progressing to subsequent organ systems. Only after immediate life threats within the primary assessment are recognized, stabilized, and reassessed does the registered nurse transition to the secondary assessment and definitive diagnostic workup.

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The Hierarchical Principle of Primary Resuscitation

In acute illness or physical trauma, organ failure follows a predictable cascade if unaddressed. Hypoxemia and inadequate cellular perfusion lead rapidly to anaerobic metabolism, lactic acidosis, cellular swelling, and irreversible multi-organ dysfunction. The ABCDE algorithm prevents diagnostic tunnel vision and premature focus on secondary injuries or distracting symptoms.

The Operational Rules of ABCDE

1. Treat First What Kills First: If a life threat is identified at any point in the sequence, the nurse must intervene immediately before continuing down the algorithm.
2. Continuous Dynamic Reassessment: Whenever a clinical intervention is executed (e.g., suctioning an airway, administering supplemental oxygen, initiating an intravenous fluid bolus), the nurse must immediately reassess from Step A (Airway) downward to verify the efficacy of the action and detect secondary deterioration.
3. Early Call for Senior Assistance: The nurse must recognize the boundaries of independent practice and trigger rapid response mechanisms (e.g., Medical Emergency Team, attending physician) concurrently while initiating life-saving first-line measures.

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Airway Assessment and Cervical Spine Protection (A)

Airway patency represents the absolute first clinical priority. Without a patent conduit for airflow, ventilation and oxygenation cannot occur, leading to hypoxic cardiac arrest within minutes.

Assessing Patency and Vocalization

• Clear and Vocal: A client who speaks in full, unlabored sentences with a normal voice demonstrates a patent airway, adequate respiratory effort, and gross cerebral perfusion.
• Partially Obstructed Airway: Identified by adventitious upper airway noises:
  • Stridor: A high-pitched, harsh, monophonic inspiratory sound indicating laryngeal edema, foreign body aspiration, epiglottitis, or severe laryngospasm. This constitutes an immediate airway emergency.
  • Snoring (Stertor): Pharyngeal occlusion caused by the relaxed tongue falling against the posterior pharyngeal wall in clients with depressed consciousness.
  • Gurgling: Fluid, blood, or gastric emesis accumulating in the upper aerodigestive tract.
  • Hoarseness or Muffled Voice ("Hot Potato Voice"): Indicates laryngeal edema, thermal inhalation injury, or retropharyngeal/peritonsillar abscess.
• Complete Airway Obstruction: Characterized by silent, frantic inspiratory efforts, profound "see-saw" (paradoxical) chest and abdominal movement, absent air movement at the mouth and nose, and rapid cyanosis.

Cervical Spine Protection in Trauma

In any patient sustaining blunt trauma (e.g., motor vehicle collisions, falls from height, diving accidents, blunt assault), cervical spine injury must be presumed until formally cleared radiologically and clinically.

• Manual In-Line Stabilization: The primary nurse or rescuer must immediately hold the head and neck in a neutral, in-line anatomical position, preventing flexion, extension, or rotational movement.
• Airway Opening Maneuver: The Jaw-Thrust Maneuver without head extension is mandatory. The nurse places fingers behind the angles of the mandible and lifts forward with both hands while stabilizing the head. The standard Head-Tilt Chin-Lift maneuver is strictly contraindicated in trauma because cervical hyperextension risks transecting or compressing an unstable cervical spinal cord injury.

Immediate Airway Interventions and Adjuncts

• Suctioning: Rigid pharyngeal suction catheters (Yankauer) must be utilized under direct visualization. Suctioning must be limited to 10 to 15 seconds per attempt, pre-oxygenating with 100% oxygen before and between passes to prevent suction-induced hypoxemia and vagally mediated bradycardia.
• Oropharyngeal Airway (OPA / Guedel):
  • Indication: Unconscious clients without an intact gag reflex to displace the tongue anteriorly.
  • Contraindication: Conscious or semi-conscious clients; an intact gag reflex will provoke violent vomiting and laryngospasm.
  • Sizing: Measure vertically from the corner of the client's mouth to the angle of the mandible (or earlobe).
  • Insertion: Insert with the curved tip pointing toward the hard palate (upside down), advance until the junction of the hard and soft palate is reached, and rotate 180 degrees into the anatomical position behind the tongue. Alternatively, use a tongue depressor to guide direct insertion without rotation (mandatory in pediatric clients to prevent hard palate laceration).
• Nasopharyngeal Airway (NPA):
  • Indication: Semi-conscious clients requiring airway support who retain a partial gag reflex or have severe trismus (clenched jaw).
  • Contraindication: Suspected basilar skull fractures (evidenced by raccoon eyes, Battle sign, CSF rhinorrhea/otorrhea, or midface trauma) due to the risk of inadvertent intracranial entry.
  • Sizing: Measure from the tip of the nose to the tragus of the earlobe, selecting a diameter matching the client's fifth digit. Lubricate with water-soluble gel and advance gently along the floor of the nasal cavity perpendicular to the face.

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Breathing and Ventilation (B)

Once airway patency is confirmed or secured, the nurse systematically evaluates the mechanics and adequacy of ventilation and pulmonary gas exchange.

Respiratory Inspection and Work of Breathing

• Respiratory Rate: The normal adult resting respiratory rate is 12 to 20 breaths/min. Tachypnea ($\ge 22\text{ to }25\text{ breaths/min}$) is the single most sensitive early physiological indicator of clinical deterioration, reflecting compensation for systemic metabolic acidosis, hypoxemia, or thoracic pathology. Bradypnea ($<10\text{ breaths/min}$) indicates central nervous system depression, opioid toxicity, or impending respiratory arrest from muscle fatigue.
• Work of Breathing and Accessory Muscle Use: Observe for sternocleidomastoid and scalene retraction in the neck, intercostal and subcostal indrawing, nasal flaring, and abdominal paradox (inward movement of the abdomen during inspiration indicating diaphragmatic exhaustion).
• Thoracic Symmetry and Deformity: Inspect for unilateral chest lag, flail chest segments (paradoxical inward motion during inspiration and outward motion during expiration caused by two or more adjacent rib fractures in two or more places), subcutaneous emphysema, and surgical scars.

Auscultation and Percussion

• Bilateral Air Entry: Systematically auscultate the anterior, lateral, and posterior lung fields. Asymmetric breath sounds point to unilateral pathology:
  • Absent or Diminished Sounds: Pneumothorax, massive hemothorax, pleural effusion, complete bronchial obstruction, or right mainstem endobronchial intubation.
  • Adventitious Sounds: Coarse or fine crackles (pulmonary edema, pneumonia), expiratory wheezes (bronchospasm in asthma or COPD), or localized bronchial breath sounds (consolidation).
• Percussion: Hyperresonance indicates trapped intrapleural air (pneumothorax), whereas dullness indicates intrapleural fluid (hemothorax) or solid consolidation.

Objective Oxygenation Assessment

• Pulse Oximetry ($SpO_2$): Target $SpO_2$ in acutely ill adults without hypercapnic respiratory failure is 94% to 98%. In clients with confirmed chronic hypercapnic respiratory failure (e.g., severe COPD), target $SpO_2$ is 88% to 92% to avert hypercapnic respiratory depression.
• Clinical Pitfall: Pulse oximetry readings are unreliable during peripheral vasoconstriction, severe hypothermia, profound shock, carbon monoxide toxicity (carboxyhemoglobin produces falsely elevated $SpO_2$ readings), and severe methemoglobinemia.

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Circulation with Hemorrhage Control (C)

Circulation assessment evaluates systemic hemodynamic integrity, end-organ perfusion, and cardiac rhythm while rapidly halting external blood loss.

Clinical Perfusion Markers

• Pulse Assessment: Evaluate central (carotid, femoral) versus peripheral (radial, pedal) pulses simultaneously. An old rule of thumb links a palpable radial pulse to a systolic blood pressure (SBP) of at least 80 mmHg, a femoral pulse to at least 70 mmHg and a carotid pulse to at least 60 mmHg. It overestimates blood pressure, so always measure it. Note rate, rhythm, and volume (e.g., weak, thready pulses indicate low stroke volume; bounding pulses indicate hyperdynamic septic vasodilation).
• Capillary Refill Time (CRT): Apply firm pressure to the distal phalanx of a fingernail or sternum for 5 seconds, then release. Normal CRT is $< 2\text{ seconds}$. Prolonged CRT ($> 2\text{ to }3\text{ seconds}$) indicates peripheral vasoconstriction, reduced cardiac output, hypothermia, or hypovolemic shock.
• Skin Perfusion and Color: Assess skin temperature and moisture over the extremities. Cold, clammy, pale, or mottled extremities signal intense compensatory sympathetic alpha-adrenergic vasoconstriction, shunting blood to vital core organs.
• Blood Pressure and Pulse Pressure:
  • Hypotension ($\text{SBP} < 90\text{ mmHg}$ or Mean Arterial Pressure $\text{MAP} < 65\text{ mmHg}$) is a late sign of circulatory decompensation.
  • Narrowed Pulse Pressure (e.g., 100/80 mmHg; pulse pressure $\le 25\text{ mmHg}$) indicates decreased stroke volume and high systemic vascular resistance, serving as a critical early sign of hypovolemic or cardiogenic shock before systolic pressure collapses.

Immediate Circulatory Interventions

• External Hemorrhage Control: Active external arterial or severe venous bleeding must be controlled immediately using direct manual pressure over the wound with sterile gauze dressings. If life-threatening extremity hemorrhage persists despite direct pressure, apply an approved arterial tourniquet proximal to the bleeding site and record the exact application time.
• Vascular Access: Secure two large-bore peripheral intravenous catheters (14-gauge or 16-gauge in the antecubital fossae). Large-bore, short-length cannulas maximize flow rates according to Poiseuille's law, permitting rapid volume resuscitation.
• Fluid Resuscitation: In non-cardiogenic shock, initiate rapid infusion of warmed isotonic balanced crystalloids (e.g., Ringer's Lactate or 0.9% Normal Saline). In severe hemorrhagic shock, activate the Massive Transfusion Protocol (MTP) with blood products infused in a balanced 1:1:1 ratio (Packed Red Blood Cells, Fresh Frozen Plasma, and Platelets) rather than excessive crystalloid dilution.

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Disability: Rapid Neurological Evaluation (D)

The Disability component rapidly quantifies central nervous system function, identifies elevated intracranial pressure or focal deficits, and checks for immediately reversible metabolic derangements.

The AVPU Scale

For rapid triage and initial evaluation, use the AVPU classification:

• A (Alert): Spontaneously awake, responsive, oriented to surroundings.
• V (Voice): Responds only to verbal stimulation (opens eyes, speaks, or moves when spoken to).
• P (Pain): Responds only to central painful stimulus (trapezius pinch, supraorbital pressure, or sternal rub).
• U (Unresponsive): Completely flaccid and unresponsive to all verbal and painful stimuli.

The Glasgow Coma Scale (GCS)

The GCS provides a standardized, granular quantification of conscious state across three discrete behavioral domains, yielding a cumulative score between 3 (deep coma/death) and 15 (fully intact):

Non-Negotiable Resuscitation Rule: "A GCS of 8 or less mandates prompt endotracheal intubation." Clients scoring $\le 8$ have lost protective airway reflexes (cough, gag, swallow) and are at extreme risk of aspiration, hypoventilation, and secondary hypoxic brain damage.

Pupillary Reflexes and Bedside Glycemia

• Pupillary Symmetry and Reactivity: Inspect pupils for size (normal 2 to 5 mm), symmetry, shape, and brisk constriction to light. A unilaterally dilated, non-reactive (fixed) pupil in an obtunded client indicates impending uncal transtentorial herniation compressing the ipsilateral third cranial nerve (oculomotor nerve).
• Bedside Blood Glucose: Capillary blood glucose measurement is mandatory during the "D" assessment. Hypoglycemia ($< 4.0\text{ mmol/L}$ or $< 70\text{ mg/dL}$) directly mimics acute stroke, status epilepticus, or coma, and causes permanent neuronal necrosis if not corrected immediately with intravenous hypertonic dextrose (e.g., 50 mL of 50% Dextrose).

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Exposure and Environmental Control (E)

The final element of the primary survey involves full physical exposure to identify occult life threats while actively safeguarding normothermia and patient dignity.

Full-Body Inspection

Remove or cut away clothing systematically to inspect the entire body surface. Search for occult hemorrhage, penetrating trauma, blunt contusions, open fractures, surgical drains, extensive rashes (e.g., meningococcal purpura, anaphylactic urticaria), petechiae, burn injuries, or transdermal medication patches (e.g., fentanyl patches contributing to opioid toxicity).

Thermal Protection and Dignity

• Hypothermia Prevention: Hypothermia in trauma or critical illness disrupts the coagulation cascade, worsens metabolic acidosis, and increases mortality (the "Lethal Triad" of trauma: hypothermia, acidosis, and coagulopathy).
• Interventions: Immediately cover exposed skin with warm blankets or forced-air warming devices, maintain a warm ambient room temperature, and administer only warmed intravenous fluids.
• Privacy and Dignity: Expose only one anatomical zone at a time, ensuring window blinds, curtains, and doors remain closed, maintaining the client's cultural dignity and comfort.

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Transition to Secondary Assessment & The SAMPLE Framework

Transitioning to the secondary assessment is appropriate only after all primary life threats under ABCDE have been identified, stabilized, and confirmed on dynamic reassessment. If the client becomes unstable at any subsequent stage, the nurse immediately aborts the secondary assessment and returns to Step A.

The SAMPLE History Mnemonic

The SAMPLE mnemonic structures the targeted clinical history obtained from the client, family, bystanders, or emergency medical services (EMS):

• S (Signs and Symptoms): Primary complaints, onset, duration, character, radiation, severity (e.g., 0-10 numeric rating scale).
• A (Allergies): True pharmacological, latex, food, and environmental allergies, noting specific past reaction characteristics (anaphylaxis vs. mild nausea).
• M (Medications): Comprehensive prescription list, over-the-counter agents, herbal preparations, anticoagulants, antiplatelets, insulin, and timing of the last administered dose.
• P (Past Medical and Surgical History): Underlying chronic conditions (diabetes, hypertension, asthma, renal failure), previous hospitalizations, surgical procedures, and immunization history (e.g., tetanus toxoid status in wounds).
• L (Last Oral Intake): Exact time and nature of the last solid food and fluid ingestion (critical for emergency anesthesia aspiration risk assessment).
• E (Events Leading to Injury/Illness): Chronological sequence of events immediately preceding the acute decompensation, mechanism of injury in trauma, or toxic exposure details.

Secondary Head-to-Toe Examination and Diagnostics

The nurse conducts a meticulous, non-invasive head-to-toe clinical examination, followed by obtaining and reviewing the investigations ordered by the medical team or permitted by protocol (arterial blood gases, full blood count, electrolytes, troponins, coagulation profiles) and radiological imaging (portable chest radiography, 12-lead ECG, focused abdominal ultrasound in trauma [FAST]).

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Primary vs. Secondary Assessment Comparison