Chapter 39

1. Chapter 39 Care of Patients with Shock

2. Shock • Widespread abnormal cellular metabolism that occurs when the human need for oxygenation and tissue perfusion is not met to the level needed to maintain cell function. • “Whole-body” response. • Shock is a “syndrome.” • Any problem that impairs oxygen delivery to tissues and organs can start the syndrome of shock and lead to a life-threatening emergency.

3. Classification of Shock by Functional Impairment • Hypovolemic shock • Cardiogenic shock • Distributive shock • Obstructive shock

4. Classification of Shock by Origin of the Problem • Hypovolemic • Cardiogenic • Basogenic • Septic

5. Processes of Shock • Initial stage (early shock) • Nonprogressive stage (compensatory stage) • Progressive stage (intermediate stage) • Refractory stage (irreversible stage)

6. Review of Oxygenation and Tissue Perfusion • Total blood volume • Cardiac output • Size of the vascular bed

7. Hypovolemic Shock • Occurs when low circulating blood volume causes a mean arterial pressure decrease; the body’s oxygen need is not met • Commonly caused by hemorrhage (external or internal) and dehydration

8. Cardiogenic Shock • Actual heart muscle is unhealthy, and pumping is directly impaired. • Myocardial infarction is the most common cause of direct pump failure.

9. Distributive Shock • Blood volume is not lost but is distributed to the interstitial tissues where it cannot circulate and deliver oxygen • Caused by loss of sympathetic tone, blood vessel dilation, pooling of blood in venous and capillary beds, capillary leak • Neural-induced distributive shock • Chemical-induced distributive shock

10. Chemical-Induced Distributive Shock • Anaphylaxis • Sepsis • Capillary leak syndrome

11. Obstructive Shock • Caused by problems that impair the ability of the normal heart muscle to pump effectively • Heart is normal, but conditions outside the heart prevent either adequate filling of the heart or adequate contraction of the healthy heart muscle • Pericarditis • Cardiac tamponade

12. Stages of Shock • Initial stage • Nonprogressive stage • Progressive stage • Refractory stage

13. Initial Stage of Shock • Baseline MAP decreased by less than 10 mm Hg • Heart and respiratory rate increased from the baseline or a slight increase in diastolic blood pressure • Adaptive responses of vascular constriction and increased heart rate

14. Nonprogressive Stage • MAP decreases by 10 to 15 mm Hg. • Kidney and hormonal adaptive mechanisms activated. • Tissue hypoxia in nonvital organs. • Acidosis and hyperkalemia. • Stopping conditions that started shock and supportive interventions can prevent shock from progressing.

15. Progressive Stage of Shock • Sustained decrease in MAP of more than 20 mm Hg from baseline. • Vital organs develop hypoxia. • Life-threatening emergency. • Immediate interventions are needed. • Conditions causing shock need to be corrected within 1 hour of the onset of the progressive stage.

16. Refractory Stage of Shock • Too much cell death and tissue damage result from too little oxygen reaching the tissues. • Body can no longer respond effectively to interventions, and shock continues.

17. Multiple Organ Dysfunction Syndrome • Sequence of cell damage caused by the massive release of toxic metabolites and enzymes. • Metabolites released from dead cells. • Microthrombi form. • MODS occurs first in the liver, heart, brain, and kidney. • Myocardial depressant factor from the ischemic pancreas.

18. Health Promotion and Maintenance • Primary prevention of hypovolemic shock • Secondary prevention of hypovolemic shock

19. Physical Assessment/Clinical Manifestations • Cardiovascular changes • Pulse • Blood pressure • Oxygen saturation • Skin changes • Respiratory changes • Renal and urinary changes • Central nervous system changes • Musculoskeletal changes

20. Assessment • Psychosocial assessment • Laboratory tests

21. Nonsurgical Management • Goals of shock management are to maintain tissue oxygenation, increase vascular volume to normal range, and support compensatory mechanisms • Oxygen therapy • IV therapy • Drug therapy

22. Drug Therapies • Vasoconstrictors, such as dopamine, epinephrine, norepinephrine, phenylephrine • Agents that enhance contractility • Agents that enhance myocardial perfusion

23. Sepsis and Septic Shock • Complex type of distributive shock—usually begins as a bacterial or fungal infection and progresses to a dangerous condition over a period of days • Sepsis—widespread infection coupled with a more general inflammatory response, known as systemic inflammatory response syndrome (SIRS), that is triggered when an infection escapes local control

24. Severe Sepsis • Progression of sepsis with an amplified inflammatory response

25. Septic Shock • Stage of sepsis and SIRS when multiple organ failure is evident and uncontrolled bleeding occurs. • Even with appropriate intervention, the death rate among patients in this stage of sepsis exceeds 60%.

26. Septic Shock (Cont’d) • Etiology and genetic risk • Incidence/prevalence • Health promotion and maintenance

27. Septic Shock: Clinical Manifestations • Cardiovascular changes • Respiratory changes • Skin changes • Renal urinary changes • Psychosocial assessment • Laboratory tests

28. Septic Shock: Interventions • Oxygen therapy • Drug therapy • Blood replacement therapy

29. Community-Based Care • Home care management • Health teaching