PART I: Medical-Surgical Nursing
Explain the surgical intervention if one is planned. For patients who have tissue loss, rest pain, or disabling claudication, surgical intervention may be necessary to open the occluded vessel or bypass the vessel to improve distal circulation.
- Endarterectomy Endarterectomy involves removal of the atheromatous obstruction via
arterial incision.
- Distal revascularization Revascularization bypasses the obstructed segment by suturing an
autogenous vein or graft proximally and distally to the obstruction.
- Percutaneous transluminal angioplasty (PTA or PTLA) A balloon-tipped catheter is inserted through the artery to the area of occlusion. The balloon is gradually inflated to ablate the
obstruction.
- Stent During an arteriogram, a hollow tube is positioned and deployed
within a stenosed vessel to stretch and improve blood flow.
Combined with angioplasty, a stent may provide longer patency of the vessel.
If necessary, use a Doppler ultrasonic probe to check pulses, holding the probe to the skin at a 45-degree angle to the blood vessel. Record the presence or absence of pulsations, as well as rate, character, frequency, and intensity of sounds.
Doppler probes are capable of evaluating the amount of blood flow in arteries in which pulses are difficult to palpate. Optimally, pulsatile blood flow will be heard. In the presence of normal blood flow, wavelike, whooshing sounds will be heard.
Protect legs and feet from pressure or damage. Decreased LE sensation increases risk of injury.
Foam protectors, special mattresses, cotton socks, and blankets are useful.
Monitor BP. Report to the health care provider any significant increase or decrease greater than 15-20 mm Hg, or as directed.
BP is another indicator of peripheral perfusion pressure. An increase in BP may interrupt the surgical site; decreased BP may cause graft occlusion.
For the first 48-72 hr after surgery (or as directed), prevent acute joint flexion in the presence of a graft.
Joint flexion can impede blood flow and perfusion. Mild foot elevation or light Ace-wrapping may help ease hyperemia of the extremity.
In the absence of acute cardiac or renal failure, encourage adequate fluid intake.
Adequate fluid intake enhances perfusion; inadequate fluid intake can lead to dehydration and poor perfusion.
ADDITIONAL NURSING DIAGNOSES/PROBLEMS:
“Perioperative Care” p. 45
PATIENT-FAMILY TEACHING AND DISCHARGE PLANNING
When providing patient-family teaching, focus on sensory information, avoid giving excessive information, and initiate
a visiting nurse referral for necessary follow-up teaching.
Include verbal and written information about the following:
✓
Progressive exercise program as prescribed by the health care team; importance of rest periods if claudication occurs.
✓
Meticulous, routine skin and foot care.
✓
Medications, including drug name, purpose, dosage, schedule, precautions, and potential side effects. Also discuss drug-drug, food-drug, and herb-drug interactions.
✓
Referral to a smoking/tobacco cessation program if
appropriate.
145
Cardiac and Noncardiac Shock
(Circulatory Failure) 17
OVERVIEW/PATHOPHYSIOLOGY
Shock occurs when tissue perfusion is severely decreased, causing cellular metabolic dysfunction. Shock is classified according to the causative event.
Hypovolemic shock:
Occurs when volume in the intravas- cular space is severely decreased and the metabolic needs of tissues cannot be met, as with severe hemorrhage or dehydration.
Cardiogenic shock:
Occurs when cardiac pump failure results in decreased cardiac output, resulting in decreased sys- temic perfusion, as with severe myocardial infarction.
Distributive shock conditions:
Characterized by a signifi- cant decrease in vascular volume. The three types are neuro- genic shock, anaphylactic shock, and septic shock.
Neurogenic shock occurs when a neurologic event (e.g.,
spinal cord injury) causes loss of sympathetic tone, resulting in massive vasodilation and decreased perfusion pressures.
Anaphylactic shock is caused by a severe systemic response
to an allergen (foreign protein), resulting in massive vasodila- tion, increased capillary permeability, decreased perfusion, decreased venous return, and subsequent decreased cardiac output.
Septic shock occurs when bacterial toxins cause an over-
whelming systemic infection, resulting in severe hypotension and decreased cardiac output.
Regardless of the cause, shock results in cellular hypoxia secondary to decreased perfusion and ultimately in cellular, tissue, and organ dysfunction. A prolonged shock state can result in death; therefore early recognition and intervention are essential.
HEALTH CARE SETTING
Critical care unit (e.g., cardiogenic shock in coronary care unit; distributive shock in medical intensive care unit [ICU])
ASSESSMENT
Early signs and symptoms:
Cool, pale, and clammy skin;
decreased pulse strength; dry and pale mucous membranes;
restlessness; change in level of consciousness; hyperventila- tion; anxiety; nausea; thirst; weakness.
Physical assessment:
Rapid heart rate (HR); decreased systolic blood pressure (SBP) and increased diastolic blood pressure (DBP) secondary to catecholamine (sympathetic nervous system [SNS]) response.
Late signs and symptoms:
Decreased urinary output, hypo- thermia, drowsiness, diaphoresis, confusion, and lethargy, all of which can progress to a comatose state.
Physical assessment:
Thready, rapid HR; low or decreas- ing blood pressure (BP), usually with SBP less than 90 mm Hg; rapid and possibly irregular respiratory rate (RR).
DIAGNOSTIC TESTS
Diagnosis is usually based on presenting symptoms and clinical signs.
Arterial blood gas (ABG) values:
May reveal metabolic aci- dosis or respiratory alkalosis (bicarbonate [HCO
3−] less than 22 mEq/L and pH less than 7.40) caused by anaerobic metabolism.
Serial measurement of urinary output:
Less than 30 mL/hr (0.5 mL/kg/hr) indicates decreased perfusion and decreased renal function.
Blood urea nitrogen (BUN) and creatinine:
Increase with decreased renal perfusion.
Serum electrolyte levels:
Identify renal complications and metabolic dysfunction as evidenced by hyperlactatemia and elevated levels of electrolytes.
Cultures of blood, sputum, wound, and urine:
To identify the causative organism in septic shock.
White blood cell (WBC) count:
Extremely elevated in septic shock due to infection. Increased eosinophils may be present in anaphylactic shock.
Complete blood count (CBC):
Hematocrit (Hct) and hemo-
globin (Hgb) may be increased in severe dehydration or
decreased in the presence of hemorrhage.
PART I: Medical-Surgical Nursing
Risk for Ineffective Peripheral Tissue Perfusion/
Risk for Decreased Cardiac Tissue Perfusion/
Risk for Ineffective Cerebral Tissue Perfusion/
Risk for Ineffective Renal Perfusion/
Risk for Electrolyte Imbalance
related to decreased circulating blood volume occurring with shock
Desired Outcome:
Within 1-2 hr of treatment, the patient has adequate perfusion as evi- denced by peripheral pulse amplitude more than 2
+on a 0-4
+scale; brisk capillary refill (less than 2 sec); SBP greater than 90 mm Hg; Sa
O2greater than 92%; mean arterial pressure (MAP) 70-100 mm Hg; HR regular and 100 bpm or less; no significant change in mental status; orientation to person, place, and time; normalized electrolytes; and urine output at least 30 mL/hr (0.5 mL/kg/hr).
ASSESSMENT/INTERVENTIONS RATIONALES
Assess and document peripheral perfusion status. Report significant findings.
Significant findings include coolness and pallor of the extremities, decreased amplitude of pulses, and delayed capillary refill.
Ineffective peripheral perfusion is an early sign of decreased cardiac output and shock and necessitates prompt intervention.
Assess BP and indicators of hypotension at frequent intervals. Notify the health provider promptly of significant findings.
Indicators of hypotension include decreased SBP of greater than 20 mm Hg below the patient’s normal range, dizziness, altered mentation, and decreased urinary output.
Immediate intervention is necessary to avoid irreversible organ damage due to poor perfusion.
If severe hypotension is present, place the patient in a supine position. This position promotes venous return. BP must be at least 80/60 mm Hg for adequate coronary and renal artery perfusion.
Assess for restlessness, confusion, mental status changes, and decreased level of consciousness (LOC).
These are indicators of ineffective cerebral perfusion/cerebral hypoxia.
If these indicators occur, intervene to keep the patient safe from harm;
reorient as indicated.
Patients with mental status changes due to poor cerebral perfusion are at risk of falling or making inappropriate decisions regarding mobility (e.g., getting out of bed without assistance).
Monitor for the presence of chest pain and an irregular HR. Report significant findings.
These are indicators of decreased coronary artery perfusion.
Decreased coronary artery perfusion necessitates prompt intervention to prevent ischemia.
Monitor urinary output hourly and check weight daily; notify the health care provider of significant findings, including urine output less than 30 mL/hr (0.5 mL/kg/hr) in the presence of adequate intake and/or weight gain.
Decreased urinary output is a sign of decreased cardiac output and ineffective renal perfusion. Weight gain may be a sign of fluid retention, which can occur with ineffective renal perfusion.
Monitor laboratory results for elevated BUN and creatinine levels; report increases.
BUN more than 20 mg/dL and creatinine more than 1.5 mg/dL are signals of ineffective renal perfusion.
Monitor serum electrolyte values for evidence of imbalances, particularly of lactate, Na+, and K+. Assess for clinical signs of hyperkalemia, such as muscle weakness, hyporeflexia, and irregular HR, and for clinical signs of hypernatremia, such as fluid retention and edema.
Hyperlactatemia (more than 2-4 mmol/L), hypernatremia (Na+ more than 147 mEq/L), and hyperkalemia (K+ more than 5.0 mEq/L) may be signs of renal and metabolic complications of shock as a result of ineffective renal perfusion and the kidneys’ inability to regulate lactate and electrolytes.
Notify the health care provider of significant findings. Electrolyte imbalances and acidosis are life threatening and need immediate correction. Correction likely will include oxygen therapy, fluid resuscitation, and replacement or excretion of electrolytes.
Avoid use of sedatives or tranquilizers. LOC can be altered by these medications, and tissue hypoperfusion makes absorption unpredictable.