I. INTRODUCTION

A. Demographics of Vascular Patients

Every individual undergoes varying degrees of atherosclerotic changes to their arterial walls as they age. Whereas some individuals will never require vascular intervention, there are those with both unmodifiable risk factors (genetic predisposition) and modifiable risk factors (smoking) that will have progressive vascular disease requiring operative intervention.

B. Consideration of Patient Risk Factors

Risk factors for peripheral artery disease include, but are not limited to, increasing age, male sex, smoking, hypertension, hypercholesterolemia, diabetes, obesity, homocysteinemia, and a family history of vascular disease. Smoking and diabetes are the most influential risk factors in determining the severity of peripheral arterial disease.

C. Disposition from the Operating Room

Vascular surgery can range in complexity from day surgical procedures, such as a diagnostic angiogram, to more invasive peripheral artery revascularization and carotid endarterectomies, to the most complex open thoracoabdominal aneurysm repair, which can require a lengthy intensive care unit (ICU) stay. The majority of these patients have labile blood pressures, secondary to poorly controlled hypertension preoperatively, and may require close hemodynamic monitoring in the postoperative period. Depending on the resources available, these patients can be monitored in the PACU, in a step-down unit, or in the ICU.

II. MANAGEMENT OF COMMON POSTOPERATIVE PROBLEMS

A. Hemorrhage

1. Workup

Tachycardia, hypotension, and low urine output in the postoperative setting are the classic signs of hypovolemia, which could be secondary to under-resuscitation in the operating room and/or postsurgical hemorrhage. If bleeding is suspected as the cause of hypovolemia, a complete blood count should be drawn and the hemoglobin trend should be assessed. It is important to note that an initial hemoglobin drop may not be detected in a patient with acute blood loss anemia until there is sufficient time for appropriate hemodilution to occur.

2. Etiology

Postoperative hemorrhage is one of the most common complications in patients undergoing many vascular procedures secondary to the placing of stents within blood vessels, suturing blood vessels to graft and suturing blood vessels to each other.

3. Management

If the patient is unstable, has high sanguineous drain output, and is clearly bleeding at a high rate, the patient should be taken back to the operating room for direct control of the bleeding. Conversely, if
the patient has a slow downward trend of hemoglobin over several days and is hemodynamically stable, further investigation can be performed to determine the source of bleeding.

A CT angiogram can be performed that can help determine the source and should help distinguish between a small amount of bleeding, which can be treated with normalization of the patient’s coagulation factor levels, and a larger amount of bleeding from an anastomosis, which may require surgical intervention. In addition, bleeding that occurs during any abdominal or extremity surgery, such as from subcutaneous tissues or omental blood vessels, can also occur with vascular surgery.

B. Pain

1. Workup

The postoperative patient who is in pain may present with tachycardia and have difficulty explaining the location and characteristics of their pain.

2. Etiology

Although vascular operations can range from the very simple to the very complex, the underlying goal of all vascular operations is to restore perfusion to the extremities and the viscera. One of the most common sources of pain specific to vascular surgery is the pain that comes with reperfusion to previously ischemic tissue. This pain can be extremely difficult to control because reperfusion often leads to cramping, burning, and swelling of the extremity.

In addition, patients can also suffer from pain that is common to most surgical procedures, namely from the incision and stretching of the tissues.

3. Management

Patients who have thoracic, abdominal, or thoracoabdominal incisions will likely benefit from having an epidural placed preoperatively. Occasionally, however, epidurals placed preoperatively may not provide sufficient analgesia and the patient may have continued pain. Pain control by means of epidural should be assessed at the bedside, and it should be determined whether the patient has sensation in the targeted area. A test bolus of 3 to 5 cc of 2% lidocaine with epinephrine can be administered through the thoracic epidural to determine if it is functioning. In the case of a nonfunctioning epidural, the anesthesia team should be consulted to either replace the epidural or to recommend other forms of pain control, such as a patient-controlled analgesia (PCA).

A PCA allows the patient to administer pain medication in previously determined doses on demand at the push of the button. If the patient is not alert enough to use a PCA, the other option is to have the patient’s nurse administer intravenous pain medications on demand at scheduled intervals.

C. Rhabdomyolysis

1. Workup

Rhabdomyolysis can occur in any patient who has had reperfusion to an ischemic extremity. The possibility of rhabdomyolysis should be considered early in the PACU, and preventative steps taken immediately to limit damage to the kidneys. The vascular patient with rhabdomyolysis will have had some degree of ischemia to their extremity and will present with pain in the affected extremity, myoglobinuria (seen as dark red-tinged urine), and a high creatine kinase.

Patients with rhabdomyolysis should have their creatine kinase trended. The creatine kinase can range from as low as 1,000 international
units (IU)/L when the patient initially exhibits signs of rhabdomyolysis to as high as 100,000 IU/L. In addition to rising levels of creatine kinase in the serum, there will also be rising levels of myoglobin in the urine. The urine may appear pink tinged and a urine dipstick will be positive for blood, but will be negative for red blood cells.

In addition to an elevated creatinine kinase and urine myoglobin, the serum potassium level will also start to rise because of its release from dying muscle cells. The potassium level should be monitored as it may rise to toxic levels and, in the context of declining renal function, the patient may require dialysis to control the serum potassium level to avoid the development of cardiac dysrhythmias.

2. Etiology

Rhabdomyolysis is a frequent concern in vascular surgery. It results when the muscles do not receive blood flow and then the muscle cells die and release creatine kinase, myoglobin, and a variety of muscle cell enzymes and electrolytes. Any patient who has had ischemia to their extremities, such as ischemia that results from an embolus that blocks blood flow to the extremity, is at risk for rhabdomyolysis.

3. Management

The management of rhabdomyolysis has been the source of controversy in recent years. Initially, it was proposed that urinary alkalization improved outcomes because it prevented the formation of precipitates that occur in acidic urine, as it inhibited the reduction-oxidation pathway of myoglobin, and it prevented metmyoglobin-induced vasoconstriction that can occur in acidic environments. However, several recent meta-analyses have demonstrated that there is no significant difference between the outcomes of urine alkalization versus intravenous fluid hydration alone.

It has been firmly established that patients who are at risk for acute kidney injury secondary to rhabdomyolysis should undergo aggressive intravenous fluid hydration. The goal for urine output should be 3 cc/kg/hour. However, the benefit of diuretics in addition to intravenous fluid hydration in the treatment of rhabdomyolysis has been controversial. Several studies have failed to demonstrate a benefit between the use of diuretics and the use of intravenous hydration alone. The benefit of diuretics is thought to arise from increasing urinary flow, but this should be pursued only after it has been confirmed that the patient has been adequately resuscitated with intravenous fluids.

Recent interest has focused on the benefit of continuous renal replacement therapy (CRRT) for rhabdomyolysis. Although the Cochrane Database of Systematic Reviews found insufficient evidence that CRRT is effective at removing myoglobin, several other studies with insufficient power have found improved outcomes following the initiation of CRRT. It has also been suggested that myoglobin has a higher percentage removal with CRRT than with hemodialysis because of the size of the protein.

D. Compartment Syndrome

1. Workup

The upper and lower extremities are the most common sites of compartment syndrome in the vascular patient. Compartment syndrome most commonly occurs following trauma injury or reperfusion of a previously ischemic extremity. The names and numbers of compartments for the arms and legs are identified in Table 4.1.

The anterior compartment of the lower extremity exhibits signs of compartment syndrome earlier than other compartments. Early signs of compartment syndrome include pain out of proportion to
expected findings and pain with passive movement. Later signs include a tense compartment to palpation, paresthesias, and persistent deep pain. Late signs include paralysis, diminished sensation, and lack of palpable pulses.