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INTRODUCTION

DEFINITION

Condition of severe impairment of tissue perfusion leading to cellular injury and dysfunction. Rapid recognition and treatment are essential to prevent irreversible organ damage and death. Common causes are listed in Table 11-1.

TABLE 11-1CATEGORIES OF SHOCK

CLINICAL MANIFESTATIONS

  • Hypotension (mean arterial bp <60 mmHg), tachycardia, tachypnea, pallor, restlessness, and altered sensorium.

  • Signs of intense peripheral vasoconstriction, with weak pulses and cold clammy extremities. In distributive (e.g., septic) shock, vasodilation predominates and extremities are warm.

  • Oliguria (<20 mL/h) and metabolic acidosis common.

  • Acute lung injury and acute respiratory distress syndrome (ARDS; see Chap. 14) with noncardiogenic pulmonary edema, hypoxemia, and diffuse pulmonary infiltrates.

APPROACH TO THE PATIENT: Shock

Obtain history for underlying causes, including cardiac disease (coronary disease, heart failure, pericardial disease), recent fever or infection leading to sepsis, drug effects (e.g., excess diuretics or antihypertensives), conditions leading to pulmonary embolism (Chap. 133), and potential sources of bleeding.

PHYSICAL EXAMINATION

Jugular veins are flat in oligemic or distributive (septic) shock; jugular venous distention (JVD) suggests cardiogenic shock; JVD in presence of paradoxical pulse (Chap. 110) may reflect cardiac tamponade (Chap. 116). Check for asymmetry of pulses (aortic dissection—Chap. 125). Assess for evidence of heart failure (Chap. 124), murmurs of aortic stenosis, acute mitral or aortic regurgitation, and ventricular septal defect. Tenderness or rebound in abdomen may indicate peritonitis or pancreatitis; high-pitched bowel sounds suggest intestinal obstruction. Perform stool guaiac to rule out GI bleeding.

Fever and chills typically accompany septic shock. Sepsis may not cause fever in elderly, uremic, or alcoholic pts. Skin lesions may suggest specific pathogens in septic shock: petechiae or purpura (Neisseria meningitidis or Haemophilus influenzae), ecthyma gangrenosum (Pseudomonas aeruginosa), generalized erythroderma (toxic shock due to Staphylococcus aureus or Streptococcus pyogenes).

LABORATORY

Obtain hematocrit, WBC, electrolytes, platelet count, PT, PTT, DIC screen, electrolytes. Arterial blood gas usually shows metabolic acidosis (in septic shock, respiratory alkalosis precedes metabolic acidosis). If sepsis suspected, draw blood cultures, perform urinalysis, and obtain Gram stain and cultures of sputum, urine, and other suspected sites.

Obtain ECG (myocardial ischemia or acute arrhythmia) and chest x-ray (heart failure, tension pneumothorax, pneumonia). Echocardiogram is often helpful (cardiac tamponade, left/right ventricular dysfunction, aortic dissection).

CVP or ...

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