Postoperative Care

After high-risk operations (eg, abdominal aortic surgery, liver resection), most patients, especially elderly ones, are treated in an intensive care unit or recovery room for < 72 hours before being returned to a standard hospital room.

After the acute recovery period, certain preventive measures are important even when convalescence is uncomplicated. Getting out of bed and sitting in a chair may be a first objective. Patients should begin to ambulate soon after surgery; patients who do not do so are more likely to rapidly lose muscle mass and strength and to develop thromboembolism. Elderly patients may need up to two assistants for several days to ambulate and transfer. Elderly patients need assistance because they are likely to have reduced baroreceptor reflexes, causing dizziness or frank loss of consciousness when they assume an upright posture for the first time after surgery.

Early Postoperative Complications

Many elderly patients experience postoperative complications during the first 2 to 3 days.

Hypoxemia: Analgesics, particularly opioids, may decrease sensitivity to the hypercapnic and hypoxic respiratory drive in elderly patients, predisposing them to arterial desaturation and hypoxemia. Debilitated patients commonly need prolonged intubation and ventilation. Elderly patients are given supplemental oxygen while being transported from the operating room to the recovery room. They should not be discharged from the recovery room until arterial saturation is similar to the preoperative level.

Pain: The elderly are more tolerant of and philosophical about pain than younger persons and, unless asked, may not report pain. However, controlling pain is as important as maintaining appropriate blood pressure and body temperature.

Postoperative delirium: Some degree of delirium occurs in up to 25% of elderly patients within 1 week of surgery. Associated with a higher incidence of complications and a poor functional outcome 6 months after surgery, delirium directly contributes to in-hospital morbidity and longer hospital stays. Certain anesthetics, meperidine, and anticholinegics seem to increase the risk of postoperative delirium. The risk of postoperative delirium is similar with general and regional anesthetic techniques; however, most patients who undergo regional anesthesia are also given opioids, benzodiazepines, or other adjuvants that increase risk. Preexisting dementia, fluid and electrolyte imbalance, drugs, sleep deprivation, frequent interruptions for nursing care, altered circadian rhythms, and an inability to keep track of time can contribute to confusion and disorientation.

Delirium in surgical patients does not appear to differ from that in other hospitalized patients, and the incidence in the two groups is similar. Postoperative delirium is characterized by difficulty in organizing and coordinating thoughts and by slowed motor function. It ranges from mild confusion to full hallucinations. Patients with delirium may remove vital drains or temporary pacemaker wires, or they may fall and injure themselves when getting out of bed.

No specific treatment is available, although certain measures can help minimize confusion and disorientation. When possible, elderly patients are transferred from the intensive care unit or recovery room, both of which are frequently noisy and brightly lit. Patients placed in such units may develop a similar disorder called intensive care unit psychosis, which is a diagnosis of exclusion, as is postoperative delirium.

Constant nighttime attendance (eg, by a family member or special aide) is preferable to use of physical or chemical restraints. Unless necessary, physical restraints should not be used in patients with delirium. If sedatives are used, antipsychotics (eg, haloperidol or the newer, atypical antipsychotics) are preferable to benzodiazepines.

Postoperative cognitive dysfunction: Elderly patients are subject to postoperative decreases in cognitive function as measured by psychometric tests. The causes of such decreases are unknown. Although generally thought to be reversible, some cognitive dysfunction may be permanent.

Hypotension: The most common cause of hypotension during the early postoperative period is hypovolemia due to inadequate replacement of intraoperative fluid losses, occult hemorrhage, or internal fluid losses (eg, reaccumulation of ascites, third-space losses). Hypotension due to other conditions is rare during the early postoperative period. It may be due to septic shock, which can develop in patients who had preoperative signs of sepsis (eg, patients with severe intra-abdominal sepsis or massive burns). Factitious causes (eg, faulty blood pressure readings) should also be considered, especially if the patient's history and physical findings do not correlate with the severity of hypotension. Blood pressure monitors must be inspected to be certain they are functioning properly.

The elderly are prone to heart failure postoperatively, and treatment in this setting usually consists of diuretics and inotropic drugs. Diastolic dysfunction develops more rapidly (usually < 1 hour after the operation) than systolic dysfunction and can greatly reduce blood pressure and flow. The most effective immediate treatment is calcium channel blockers.

Hypothermia: Immediately after a long operation, body temperature may decrease to 32.2° to 35.0° C (90° to 95° F). Treatment includes warming IV and other fluids and using convection warming systems. A vacuum chamber around the forearm and hand may also be helpful; this device creates a low-level vacuum (about 40 mm Hg), thus increasing blood flow to the extremity. A warming pad then efficiently transfers heat to the extremity. Early evidence suggests that this approach may be more efficient than convection blankets for warming elderly patients; however, extra care must be taken to avoid superficial burns.

Respiratory problems: In the elderly, the ability to protect the airway from aspiration is markedly decreased. Therefore, the physician makes sure the patient's airway reflexes (eg, gag reflex, swallowing mechanisms) are adequate before removing an endotracheal tube. Atelectasis is very common among frail elderly patients and predisposes them to pneumonia. In debilitated patients with chronic dehydration, thick copious sputum may develop in the lungs after even minimal hydration. For such patients, percussion and postural drainage must be performed frequently and aggressively.

Sometimes, elderly patients with respiratory problems require prolonged mechanical ventilation, even though it may introduce complications (eg, pneumonia, atelectasis).

Fluid and electrolyte imbalance: In the elderly, the ability to maintain homeostatic levels of fluids and electrolytes is reduced, and the margin between too little and too much fluid is relatively narrow. Overexpansion of the extracellular compartment from excess isotonic fluid administration may be dangerous because cardiopulmonary reserves are limited in the elderly.

During the early postoperative period, the body normally retains water and sodium, and the elderly may have difficulty eliminating the excess fluid.

Initially, the amount of IV fluids can be estimated, but fluid administration should be adjusted to optimize blood pressure, pulse, and urine output (which are closely monitored). Central venous pressure, pulmonary wedge pressure, and urine output measurements help determine fluid requirements. Enough fluids are given to replace insensible fluid losses and measured or estimated external losses and to produce a urine output of 0.5 mL/kg/hour, or about 30 mL/hour.

When external losses are minimal, fluid requirements are usually 1500 to 2500 mL for 24 hours. However, more fluids may be needed if third-space sequestration of fluids is excessive (eg, because of a distended bowel or inflammation of subcutaneous tissues due to burns). The sequestered fluid is usually mobilized on the 3rd to 5th day after surgery.

Electrolyte replacement must include potassium 20 to 100 mEq/day IV or po to replace losses (about two thirds is lost in urine, and the rest from the gastrointestinal tract). If potassium replacement is inadequate, postoperative ileus may be prolonged and resistant metabolic alkalosis may develop. Postoperative ileus delays return to feeding and can prolong hospitalization. Calcium and magnesium may be replaced if serum levels are low.

Hyponatremia is common among elderly patients, particularly among men undergoing transurethral resection of the prostate because hypotonic irrigation solution is absorbed through the open venous sinuses of the prostate. Symptoms appear when the sodium level is < 130 mEq/L, and confusion or a seizure may occur a few days after surgery.

The patient's total body sodium content and total body free water content may be increased, normal, or decreased. Pulmonary edema, excessive peripheral edema, or evidence of major third-space losses suggests increased total body sodium content. Total body free water content may be increased because excess 5% dextrose (in water) is administered postoperatively or because surgery alters the body's responses, resulting in high levels of antidiuretic hormone.

If hyponatremia is due to inadequate sodium intake, 0.9% sodium chloride solution should be given cautiously, avoiding increases in sodium > 10 mEq/L/24 hours. More rapid replacement may result in central pontine myelinolysis. If hyponatremia is due to water overload, 0.9% sodium chloride solution and a diuretic should be given cautiously. In either case, electrolyte levels are monitored frequently. A sodium chloride solution of 3% or 5% is rarely indicated, and its use can result in severe hypernatremia and central nervous system adverse effects.

Nutritional deficiencies: Early, aggressive nutritional support should be given to patients with malnutrition, those with complications (eg, sepsis), and those who have lost > 10% of their premorbid weight. Supplemental oral feedings, tube feedings, or total parenteral nutrition may be given, depending on the patient's condition. If anorexia or dysphagia makes oral feeding difficult but gastric and intestinal motility and absorption are normal, enteral feedings may be given by continuous drip. In such cases, the enteral route is preferable to the parenteral route because it causes fewer complications, costs less, and may have a trophic effect on the intestine. Total parenteral nutrition is used when intestinal motility or absorption is abnormal.

Postoperatively, the metabolic rate, measured by oxygen consumption, briefly increases (usually to 20 to 40% more than the normal basal metabolic rate) unless a complication such as sepsis develops. Age, sex, height, and weight affect the basal caloric requirement, but body temperature, protein losses through wounds, and muscular work related to physical activity (eg, ambulation) do not. A total daily caloric requirement of 1.2 to 2 times the basal metabolic rate is generally adequate.

The appropriate mixture of substrates, carbohydrates, proteins, and fats to meet the patient's metabolic needs to produce a positive nitrogen balance must be given. Glucose (a carbohydrate) infused at 5 mg/kg/minute provides enough calories to prevent the breakdown of amino acids as an energy source and suppresses endogenous glucose production via hepatic gluconeogenesis, which requires mobilization of amino acids as gluconeogenic precursors. This infusion rate also approximates the maximum rate of glucose oxidation for a bedridden patient. Any additional glucose is converted to fat.

For most elderly patients, protein infused at 0.5 to 1.0 g/kg/day is sufficient to maintain a positive nitrogen balance. This rate can be increased to 1.5 to 2.5 g/kg/day if needed.

Fats must be given (parenterally or enterally) to meet the patient's total caloric requirement. Fats supply essential fatty acids and enough calories to minimize the mobilization of endogenous proteins for energy and gluconeogenesis.

Other complications: Pressure sores, constipation, and complications from urinary catheters may also occur postoperatively.

Late Postoperative Complications

Antibiotic-associated pseudomembranous colitis: This disorder should be considered when diarrhea, which is common after abdominal operations, occurs postoperatively in a patient who has received antibiotics. Antibiotics may alter the balance in normal gut flora, allowing overgrowth of Clostridium difficile. Cephalosporins and extended-spectrum penicillins (eg, ampicillin) are most commonly implicated, but clindamycin, lincomycin, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole have also been implicated.

Diarrhea usually develops within 1 to 10 days after antibiotics are started. In one study of elderly patients, diarrhea developed an average of 2.7 days after antibiotics were started. If diarrhea occurs postoperatively, stool specimens are obtained immediately for bacterial culture and toxin analysis; up to 75% of patients with postoperative diarrhea have C. difficile infections. Sigmoidoscopy may also help make the diagnosis. Treatment is most commonly undertaken with metronidazole 250 mg po qid for 10 days.

Intra-abdominal abscesses: Intra-abdominal abscesses are located deep to the fascia, not within the surgical wound. The elderly may not have the typical symptoms of persistent fever and localized abdominal or flank tenderness, or they may have only vague complaints.

Intra-abdominal abscesses may be subphrenic, subhepatic, pelvic, or intraloop and may be difficult to localize. CT and ultrasonography are useful in diagnosis and localization and in the percutaneous placement of catheters for drainage. However, surgical drainage is the definitive treatment. During or immediately after surgical drainage, hemodynamic instability due to the distributive shock of sepsis frequently occurs.