General Surgery (Board Review Series) 1st Edition

2

Surgical Complications

Patrick J. O'Neill

1. General Principles

• Surgical complications may be defined as any deviation from the normal expected postoperative recovery.

1. Most complications result from

• poor operative technique.
• magnitude of the operation.
• general medical condition of the patient.
• chronic medications taken by the patient.

1. One complication may follow another.

• For example, myocardial infarction may occur secondary to anemia from acute hemorrhage.

1. Surgical care

• should be well plannedat the preoperative, intraoperative, and postoperative level (Table 2-1).

1. Prevention of complications

• remains the best form of management.

1. Nutritional care
2. Optimizing the patient's preoperative nutritional status

• will help decrease the rate of many postoperative complications.

1. Weight loss

• in obese patients decreases the risk of wound and pulmonary complications.

2. Pulmonary care
3. Cessation of smoking

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• 6 weeks before surgery will decrease the incidence of pulmonary complications from 50% to 10%.

1. Early postoperative ambulation and aggressive respiratory therapy

• may help prevent pulmonary complications.

Table 2-1. The Stages of Complete Surgical Care

Preoperative Understand all surgical and anesthetic options and risks Understand the patient's general medical condition and potential dangers Try to improve general health of the patient (e.g., nutrition, smoking cessation) Have a thorough knowledge of the patient's current medications Intraoperative Use meticulous surgical technique and minimize time under anesthesia Optimize the patient's physiological condition and vital signs Use appropriate antithromboembolic and anti-infective measures Postoperative Frequently examine and closely monitor the patient Detect and correct any abnormalities early Normalize the patient as soon as possible (e.g., early ambulation, enteral feeding when possible) Remove surgical tubes as quickly as possible Administer appropriate postoperative pain control

1. Complications Specifically Related to Surgery
2. Bleeding
3. Postsurgical bleedingis most often caused by the lack of adequate hemostasis at the time of surgery.

• The absence of bleeding from other sites suggests surgical bleeding rather than an underlying coagulopathy.

2. Risk factorsinclude

• perioperative anticoagulant therapy.
• vigorous coughing or excess activity.
• poor blood pressure control.
• an underlying coagulopathy.

3. Forms of surgical bleeding
4. Hematoma formation
5. Small hematomas

• may be observed because they may resorb without complication.

2. Large hematomas

• and those in compromising locations (e.g., neck, mediastinum) require operative evacuation.

1. Hemoperitoneum

• is defined as a collection of blood within the abdominal cavity.
• is the most common cause of hypovolemic shockin the first 24 hours after abdominal surgery.

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1. Signs and symptomsinclude

• low-grade fever.
• tachycardia.
• hypotension.
• oliguria.
• peripheral vasoconstriction.

2. Diagnosis

• Worsening anemia or persistent anemia despite blood transfusion is suggestive of the diagnosis.
• Computed tomography (CT) scanning can confirm the diagnosis when it is suspected.
• CT scanning should not be performed in a hemodynamically unstable patient.

3. Treatment consists of

• appropriate volume resuscitation.
• correction of coagulopathyif one exists.
• re-operationto obtain hemostasis.

4. Underlying coagulopathies

• can frequently contribute to perioperative bleeding.
• require treatment specific for the disorder (Table 2-2).

1. Preoperative history

• is the most reliable measure for determining the presence of a coagulopathy.

1. Risk factorsinclude

• positive family historyfor inherited coagulopathies.
• abnormal bleedingwith normal activities (e.g., brushing teeth) or abnormal menstrual bleeding.
• abnormal bleedingafter minor procedures or trauma.
• medications(e.g., aspirin, dipyridamole, warfarin, heparin).
• positive medical/surgical historyof conditions predisposing to coagulopathies.

1. Appropriate treatment measures

• for managing coagulopathies are also included in Table 2-2.

1. Wound problems
2. Hematoma formation(see section II A 3 a)
3. Seroma

• Seroma is a collection of fluid in the wound usually secondary to liquefaction of necrotic fator disruption of lymphatic drainage.
• Large seromasmay delay wound healing and increase the risk of infection.

1. Risk factorsinclude

• skin flap formation.
• inadequate wound closure.

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• lymphatic disruption.

Table 2-2. Characteristics and Treatment of Coagulopathies in Surgical Patients

Disease Etiology Signs and Symptoms Treatment Congenitalcoagulopathy Hemophilia A (classic hemophilia) Hemophilia B (Christmas disease) Von Willebrand's (vW) disease X-linked factor VIII deficiency X-linked factor IX deficiency Factor VIII: vW deficiency Elevated PTT, hemarthrosis Elevated PTT Increased bleeding time, with or without elevated PTT Cryoprecipitate, factor VIII Cryoprecipitate Cryoprecipitate, DDAVP Acquired coagulopathy Vitamin K deficiency Liver failure Hypothermia Heparin therapy Warfarin therapy Dilutional DIC Dietary deficiency, malabsorption Decreased factor production Impaired factor Promotes anti-thrombin III activity function Vitamin K antagonism Massive crystal-loid or blood transfusion Trauma, sepsis, burns, malignancy, obstetrical complications, anaphylaxis Elevated PT Elevated PT/PTT Elevated PT/PTT Elevated PTT Elevated PT Elevated PT/PTT, thrombocytopenia Diffuse bleeding, elevated PT/PTT, decreased fibrinogen, increased FDP and D-dimers, thrombocytopenia Vitamin K, FFP Vitamin K, FFP Rewarming, FFP Protamine Vitamin K, FFP Platelets, FFP Treat primary cause, supportive care, cryoprecipitate, vitamin K, FFP, platelets, antithrombin III Platelet disorders Thrombocytopenia Poor function (uremia, aspirin) Platelet counts >40,000 typically ensure hemostasis Variable Petechiae, mucocutaneous bleeding, prolonged bleeding time Petechiae, mucocutaneous bleeding, prolonged bleeding time Platelets Dialysis, DDAVP, cryoprecipitate, conjugated estrogens DDAVP = 1-deamino-8-D-arginine vasopressin; DIC = disseminated intravascular coagulation; FDP = fibrin degradation products; FFP = fresh frozen plasma; PT = prothrombin time; PTT = partial thromboplastin time.

1. Treatment

• Generally, treatment involves observationbecause attempted drainage further increases the possibility of infection.
• Persistent seromasmay represent a lymphocele, requiring surgical exploration and ligation of the injured lymphatic vessels.

3. Wound infection(see Chapter 4)
4. Dehiscence

• involves a partial or total disruption of fascial layersafter surgical closure.

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• occurs most commonly between postoperative days 5 and 8.

1. Risk factors include

• poor surgical technique (e.g., devascularization of tissue, inadequate closure).
• increased intra-abdominal pressure(e.g., obesity, bowel obstruction, ascites).
• factors associated with deficient wound healing(see Chapter 5).
• advanced age.
• diabetes.
• renal failure.
• immunosuppression(e.g., cancer, chronic steroid use).
• hepatic failure.

1. Dehiscence may frequently be associated with

• coughing.
• excessive activity.
• retching.

1. A common signof dehiscence is

• sudden discharge of serosanguinous fluid from the incision.

1. Evisceration

• Evisceration is wound dehiscencewith the extrusion of abdominal contents.
• Mortality with evisceration is greater than 10%.

1. Treatment

• of partial dehiscencegenerally involves elective fascial repair. Delayed repair is generally performed when a wound infection is present.
• of eviscerationconsists of immediate wound coverage with sterile, moist towels and emergent surgical exploration and fascial repair.

1. Postoperative pain
2. Normal postoperative pain

• should subside within 4–6 days.

2. Extraordinary pain may be associated with

• excessive repetitive motion.
• wound infection.
• occult dehiscence.
• granuloma or neuroma formation (rare).

3. Treatment involves

• early identification.
• management of the cause of persistent, severe pain.

III. System-Specific Complications

1. Central nervous system complications

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1. Focal neurologic signs noted postoperatively may be secondary to

• direct injury to the brain, spinal cord, or peripheral nerves.
• complications of spinal, epidural, or regional anesthesia.
• focal ischemia or infarctionfrom an embolic or thrombotic source.

2. Prolonged altered consciousness

• after general anesthesia may also result from poor metabolism of anesthetic agents.

1. Risk factorsinclude

• advanced age.
• renal or hepatic insufficiency.
• obesity.

1. Differential diagnosis includes

• hypoxic brain injuryor cerebral hypoperfusion.
• diabetic coma or hypoglycemic episodes.
• strokes, caused by hypertensive, embolic, or thrombotic injury.

3. Postoperative seizuresmay be secondary to

• cerebral injury.
• pre-existing seizure disorder.
• metabolic abnormalities.
• adverse medicine reactions.
• delirium tremens.

1. Evaluationincludes

• complete laboratory studies [complete blood count (CBC), electrolytes, liver function studies].
• review of potential medicine interactions.
• a CT scan of the head.

1. Treatmentincludes

• close observation with supplemental oxygen.
• intravenous (IV) fluids.
• correction of any metabolic abnormalities.
• anticonvulsants or benzodiazepines, if seizures persist.

4. Psychosis or delirium may be precipitated by

• anxiety.
• sleep deprivation.
• certain drugs (e.g., pain medications).
• hypoxia.
• electrolyte abnormalities.
• alterations in body image as a result of surgery.

1. The incidence is higher

• after cardiac surgery.
• in the elderly.
• in those with chronic disease.

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1. It generally occurs

• after postoperative day 3 and is frequently preceded by a lucid interval.

1. Characteristicsinclude

• disorientation.
• memory impairment.
• disturbed speech, sleep, or psychomotor activity.
• rapid onset, often at night.
• signs or symptoms unrelated to a specific organic factor.

1. Treatmentconsists of

• identification and management of factors contributing to the psychosis or delirium as outlined in Table 2-3.

5. Withdrawal symptoms

• occurring after stopping mood-altering substances occur in patients at risk for substance dependence.

1. Signs and symptomsinclude

• personality changes.
• anxiety.
• diaphoresis.
• tachycardia.
• hypertension.
• tremor.

1. Time of onset depends on

• the half-life of the abused substance.

6. Delirium tremens

• is defined as a severe withdrawal syndrome precipitated by sudden abstinence in an alcohol-dependent person.

1. Findingsinclude

• hyperventilation.
• agitation.
• overactivity.
• confusion.
• metabolic alkalosis.
• hypomagnesemia.
• hypokalemia.
• hallucinations and seizures (occur in the later stages).

Table 2-3. Risk Factors for Postoperative Psychosis or Delirium

§ Surgery-associated effects (e.g., hypoxia, hypercapnia, hypotension, sepsis) § Advanced age or baseline dementia § Chronic drug or alcohol abuse § Central nervous system lesions § Metabolic disorders (e.g., uremia, heptic failure, acidosis) § Medication side effects (e.g., meperidine, cimetidine, and corticosteroids) § Sleep deprivation and loss of normal circadian rhythm

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1. Treatment
2. With proper treatment, the syndrome usually improves within 72 hours.
3. Treatmentincludes

• thiamine(vitamin B₁).
• magnesium.
• benzodiazepines.
• correction of nutritional deficienciesor other metabolic abnormalities.

1. Pulmonary complications

• are the largest single cause of postoperative morbidity.
• are associated with the risk factors in Table 2-4.

1. Atelectasis

• represents a partial collapse of alveoli.
• accounts for 90% of postoperative pulmonary complications.
• occurs most frequently in the first 48 hoursafter surgery.

1. Ventilation/perfusion (V/Q) mismatchesresult in relative hypoxemia.
2. A coexisting feveris usually low-grade and self-limited.
3. Diagnosisis made by

• radiographic signs (e.g. characteristic discoid infiltrate, elevated hemidiaphragm).
• physical examination signs (e.g., basilar crackles, decreased breath sounds).

1. Preventive and therapeutic measuresinclude

• early mobilization.
• pulmonary therapy(e.g., cough, deep breathing, incentive spirometry).
• adequate pain control.

Table 2-4. Risk Factors for Postoperative Pulmonary Complications

Patient co-morbidities Advanced age Obesity Pre-existing chronic lung disease (e.g., COPD) History of smoking Poor cough effort postoperatively Surgery-related factors Long duration of anesthesia Prolonged mechanical ventilation Chest or upper abdominal surgery Abdominal distention Inadequate pain control Iatrogenic factors Oversedation or excessive narcotic analgesic use Endotracheal tube malposition COPD = chronic obstructive pulmonary disease.

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2. Pneumonia(see Chapter 4)
3. Aspiration

. Gastric secretions

• are the usual source.
• result in a chemical pneumonitis (Mendelson's syndrome).

1. Minor amounts of aspiration during surgery

• are frequent and well tolerated.

1. Significant aspiration

• is normally prevented by the esophageal sphincters and the epiglottis.

1. The magnitude of injuryis proportional to the

• volume of aspirate.
• frequency of aspiration.
• pH of aspirates.

1. Aspiration pneumonia

• is associated with a high mortality.

1. Risk factors for aspirationinclude

• decreased sensorium (e.g., head injury, narcosis).
• nasogastric tube placement.
• intestinal obstruction.
• pregnancy(caused by increased abdominal pressure and decreased lower esophageal sphincter tone secondary to progesterone).

1. The lobes most frequently affectedinclude the

• posterior right upper lobe.
• superior right lower lobe because of the orientation of the right bronchus.

1. Common signsinclude

• tachypnea.
• crackles on examination.
• hypoxia.

1. Treatmentinvolves

• appropriate airway control.
• aggressive airway hygiene.
• adequate fluid resuscitation.

4. Bronchoscopy

• may be necessary to remove solid material.

5. Antibiotics

• The use of antibiotics is controversial.
• Antibiotics should only be used for aspiration resulting in pneumonia and not for aspiration alone.
• The choice of agents should be based on culture results, although initial empiric therapy is often used to treat potential causative organisms (e.g., gastrointestinal or oral flora).

6. Prevention remains the most important strategy, including

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• preoperative fasting.
• proper patient positioning.
• careful intubation.

4. Pleural effusion

• is a collection of fluid in the pleural space.

1. Transudates versus exudates
2. Properties and associated diseases

• are listed in Table 2-5.

1. Gross blood in pleural fluid may represent

• iatrogenic vascular injuries.
• trauma.
• malignancy.
• pulmonary infarction.

1. Findingsinclude

• dyspnea.
• decreased breath sounds.
• dullness to percussion on examination.
• radiographic evidence of pleural fluid.

1. Treatmentoptions include

• observationof small asymptomatic effusions.
• drainage(e.g., thoracentesis, tube thoracostomy) for symptomatic cases (e.g., respiratory compromise).

Table 2-5. Properties of Pleural Effusion Fluid

Components Transudate* Exudate† Protein < 3 g/dL > 3 g/dL Specific gravity < 1.016 > 1.016 LDH (effusion:serum) < 0.5 > 0.6 Glucose 60% of serum level Low Amylase Low > 500 units/ml RBC count < 10,000 cells/mm3 > 100,000 cells/mm3 WBC count < 1000 cells/mm3 > 1000 cells/mm3 LDH = lactate dehydrogenase; RBC = red blood cell; WBC = white blood cell. *Transudates can be found in hepatic failure, nephrotic syndrome, congestive heart failure, viral infection, and severe lobar atelectasis. †Exudates can be found in malignancy, empyema, abdominal infection, pancreatitis, trauma, pulmonary infarction, chylothorax, and tuberculosis.

1. Cardiac complications
2. Arrhythmias

• usually appear either intraoperatively or within 1–3 days postoperatively.

1. Intraoperative arrhythmias

• usually occur during induction of anesthesia.

2. Risk factorsinclude

• type of anesthesia(especially halothane).

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• use of sympathomimetics.
• digoxin toxicity.
• hypercapnia.
• electrolyte abnormalities.

3. Treatmentinvolves

• correction of underlying abnormalities.
• occasional administration of antiarrhythmic agents.

1. Postoperative arrhythmias may be associated with

• hypokalemia.
• hypoxia.
• alkalosis.
• digoxin toxicity.
• sympathetic stimulation (i.e., pain).
• myocardial ischemia.
• invasive cardiac monitoring.

1. Most patients are asymptomatic;however, any patient with chest pain, palpitations, or dyspnea must be evaluated for a cardiac event.
2. Postoperative hypertension

• Postoperative hypertension may result from an exacerbation of underlying disease or may be secondary to poor pain control.
• Treatmentinvolves resumption of home antihypertensive medications and adequate pain control.

3. Myocardial infarction

. The incidence is

• 0.4% in all patients undergoing surgery.
• 5%–12% in patients having operations related to vascular disease (e.g., aortic aneurysm).

1. Risk factorsinclude

• congestive heart failure.
• ischemic heart disease.
• age older than 70 years.
• significant atherosclerotic disease.

1. Postoperative factorsinclude

• hypotension.
• anemia.
• hypoxemia.

1. To decrease the risk for developing myocardial infarction

• avoid hypotension and hypoxemia.
• administer perioperative beta-blockers.

1. Signs and symptoms
2. Most patients are initially asymptomaticowing to residual anesthesia and analgesia.
3. The signs and symptoms of myocardial infarction include

• chest pain.

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• hypotension.
• a new arrhythmiaassociated with electrocardiogram (ECG) changes and elevated cardiac enzyme levels.

4. Cardiac failure

• may occur perioperatively in patients with marginal cardiac function.

1. Risk factorsinclude

• volume overload.
• postoperative myocardial infarction.
• arrhythmias.

1. Prevention and treatmentinvolves

• appropriate management of underlying cardiac disease.
• careful monitoring of the patient's volume status.

1. Pancreatitis

• occurs infrequently, however, approximately 10% of all pancreatitis cases are related to surgery.

1. The incidence is

• 1%–3% when the operative procedure is in the vicinity of the pancreas.
• greater than 1%–3% when the biliary tract is manipulated.

2. Risk factorsinclude

• a history of pancreatitis.
• parathyroid surgery (i.e., acute changes in serum calcium levels).
• cardiopulmonary bypass.
• renal transplantation.

3. Signs and symptomsinclude

• fever.
• epigastric pain.
• hyperamylasemia.
• hypocalcemia.
• unexplained renal or respiratory compromise in a postoperative patient.

1. Gastrointestinal complications
2. Acute gastritis and duodenitis

• may occur in postoperative patients, particularly in the critically ill.

1. Significant bleedingmay occur.
2. Prevention involves

• postoperative administration of agents that inhibit acid production(e.g., famotidine) or augment the mucosal barrier (e.g., sucralfate).

2. Intestinal ileus

• is a depression in the normal propulsive activity of the intestine by the enteric nervous system.
• frequently occurs after abdominal operations (see Chapter 13).

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1. A slightly distended abdomenand absent or hypoactive bowel sounds are frequently present.
2. Potential factors contributing to persistent ileus include

• electrolyte abnormalities (hypokalemia).
• coexisting infection.
• excessive narcotic use.

1. Treatment includes

• correction of any contributing abnormality and patience.

3. Anastomotic leaks

• may result in abscess formation, enterocutaneous fistulae(see Chapter 13), or diffuse peritonitis.

1. Risk factors include

• poor intestinal perfusion(colonic anastomoses are at higher risk because of their more tenuous blood supply).
• technical failure(e.g., excessive tension, devascularization during repair).
• concurrent infection or inflammation.
• distal obstruction.

1. Some large bowel anastomotic leaks

• are well localized.
• can be managed with percutaneous drainage of potential fluid collections without the need for surgery.

1. Other leaks

• are not well localized.
• require reoperation for prevention and treatment of potential sequelae of anastomotic breakdown.

4. Other gastrointestinal complications may include

• postoperative colitis (see Chapter 4).
• mechanical obstruction.
• intussusception.
• colonic pseudo-obstruction (Ogilvie's syndrome) [see Chapter 13].

1. Acute renal failure (ARF)

• is generally defined as an abrupt impairment in renal functionassociated with elevations in plasma creatinine (Cr) and urea.

1. Low urine output is frequently present

• oliguria(defined as less than 0.5 mL/kg urine output per hour) or anuria.

2. Characteristics of ARF

• in surgical patients are outlined in Table 2-6.

3. Hypovolemia

• is the most common cause of ARF in surgical patients.

1. The fractional excretion of Na⁺(FE_Na)

• may help differentiate prerenal causes of renal failure from other causes.

1. The formula for determining FE_Nais

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Table 2-6. Causes, Diagnosis, and Treatment of Acute Renal Failure in Surgical Patients

Causes Diagnosis Treatment Prerenal causes [hypovolemia, decreased renal blood flow (congestive heart failure, cirrhosis, NSAIDs, ACE inhibitors)] BUN:creatinine > 20, FENa < 1% Volume replacement, correct underlying abnormality Renal causes [acute tubular necrosis, toxins (contrast agents, aminoglycosides), rhabdomyolysis, hemolysis] Tubular cells on urinalysis, FENa > 2%, hemoglobinuria, myoglobinuria Remove offending agent, restore intravascular volume, treat associated abnormalities Postrenal causes [cancer (prostate, cervix), bladder outlet obstruction (BPH, urethral stricture, clogged urinary bladder, neurogenic bladder), accidental ureteral ligation or injury, pelvic abscess] Ultrasound, signs of obstruction Treat cause of obstruction ACE = angiotensin-converting enzyme; BPH = benign prostatic hypertrophy; BUN = blood urea nitrogen; FENa = fractional excretion of Na; NSAIDs = nonsteroidal anti-inflammatory drugs.

1. FE_Na

• of less than 1% suggests a prerenal source.
• of greater than 2% suggests a primary renal source.

4. Inadequately treated ARF leads to

• progressive metabolic acidosis.
• hyperkalemia.
• severe uremia.
• volume overload.

5. Hemodialysis

• may be necessary as a bridge until renal function returns to normal.

1. Genitourinary complications
2. Postoperative urinary retention

• Postoperative urinary retention may occurafter any surgery, but especially after pelvic and perineal procedures or after epidural or spinal anesthesia.
• Prevention includes
• catheterizing the bladder for long cases or for those where large volumes of IV fluids are used.
• removing the bladder catheter and encouraging early postoperative voiding.

2. Urinary tract infection(see Chapter 4)

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1. Vascular complications
2. Iatrogenic IV catheter complications
3. Pneumothorax

• represents the presence of air in the pleural cavity with collapse of the lung.

2. Risk factors include

• central line placement.
• recent thoracotomy.
• trauma to the chest.
• underlying severe pulmonary disease.

3. Diagnosis

• is made on examination by decreased breath sounds and hyperresonance to percussion.

4. Confirmation

• A chest radiographusually confirms the diagnosis.

5. Treatment includes

• tube thoracostomy.
• evacuation of air from the pleural space.

1. Catheter sepsis may occur from

• local infection.
• hematoma.
• a break in sterile technique.

1. Other complications include

• hemothorax.
• cardiac punctureand tamponade.
• arterial injury, embolization, and air emboli.

3. Air can enter the venous system

• when a catheter is left open, exposing air at atmospheric pressure to low or negative intrathoracic pressure.

4. With a large embolus

• air lodges in the right atriumand prevents adequate right ventricular filling.

5. Symptoms include

• hypotension.
• jugular venous distention.
• tachycardia.

6. Treatment

• Placing the patient in the left lateral decubitus and Trendelenburg positions can help to dislodge air from the right atrium and trap it in the right ventricle.
• The best treatment involves prevention with careful technique in placement of the catheter.

1. Iatrogenic cardiac tamponade
2. This may occur

• with placementof a central venous catheter.

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• after coronary artery bypass grafting(CABG).

1. Diagnosis classically is made clinically

• by Beck's triad (i.e., hypotension, jugular venous distension, and muffled heart sounds), in addition to equalization of pulmonary and systemic blood pressures.

2. Confirmation

• An echocardiogrammay be used to confirm the diagnosis in some cases; however, the diagnosis is primarily based on examination.

3. Treatment involves

• decompression of the pericardial spacewith pericardiocentesis.
• surgical drainage and repair of the injured site.

2. Deep venous thrombosis (DVT)
3. DVTs may be present

• in approximately 40% of postoperative patients.

1. Most thrombi originate

• in the deep venous system of the lower extremities.

1. Clot may propagate cephalad into

• the popliteal, femoral, and iliac systems.

1. Most (more than 80%) pulmonary emboli originate

• from above the knee.

1. Risk factors include Virchow's triad

• vascular stasis(e.g., venous insufficiency, obesity)
• abnormal vessel walls(e.g., fractures)
• hypercoagulability(e.g., estrogen therapy, pregnancy, cancer).

1. Diagnosis is difficult

• because 50% of patients are asymptomatic.

1. Possible signs and symptoms include

• lower extremity swelling.
• fever.
• pain.
• Homan's sign (calf pain with foot dorsiflexion).

1. Confirmation is made either with

• lower extremity duplex ultrasound examination.
• angiographic evaluation of the venous system.

1. Treatment includes anticoagulation therapy(e.g., heparin).

• If anticoagulation is contraindicated, some patients may benefit from placement of a filter within the inferior vena cava (Figure 2.1) to prevent pulmonary embolization.

1. Preventive measures include

• early mobilization.
• the use of support hose or sequential compression devices.
• subcutaneous administration of heparin.

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Figure 2-1. Inferior vena cava filter. (A) Simon-Notinol filter. (B) Abdominal radiograph showing deployment of the filter from a catheter passed percutaneously. (Reprinted with permission from Daffner RH: Clinical Radiology: The Essentials, 2nd ed. Baltimore, Williams & Wilkins, 1999, p 66.)

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3. Pulmonary embolus

• is one of the most common causes of sudden death in hospitalized patients.

1. Thromboemboli

• from the deep venous system of the lower extremities and pelvis lead to mechanical obstruction of the pulmonary arterial system.

1. Risk factors include

• history of pulmonary embolism.
• older age.
• heart disease.
• obesity.
• malignancy.
• major trauma (especially spinal cord injury and pelvic or femoral shaft fractures).
• varicose veins.
• women who are pregnant or postpartum or receiving estrogen therapy.

1. Large embolimay result in

• decreased cardiac output.
• hypotension.
• impaired oxygenation caused by bronchospasm and vasospasm.

1. Other signs include

• hemoptysis.
• pleural friction rub.
• new cardiac gallop.
• ECG changes (e.g., diffuse ST elevation).

1. Possible radiographic findings include

• diminished pulmonary vascular markings (Westermark's sign).
• pleural effusion.
• a new pulmonary infiltrate.

1. Key for management of pulmonary emboli includes

• early recognitionof suspicious signs and symptoms.
• prompt diagnosisand treatment.

1. Confirmation is possible with

• V/Q scan.
• pulmonary arteriogram.

1. Treatment involves

• appropriate airway management.
• cardiovascular support (e.g., mechanical ventilation, volume resuscitation).
• anticoagulation therapy (heparin).
• thrombolytic therapyor pulmonary embolectomy for severe cases.

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4. Superficial thrombophlebitis

• is frequently associated with infected or infiltrated peripheral IV catheters.

1. Prevention is possible

• with meticulous placement and care of these catheters.

1. Diagnosis is made by clinical findings of

• a swollen, tender, red, warm, indurated, palpable cord along a vein.

1. Treatment involves

• removal of the intravenous catheter.
• elevation and local moist heat for pain relief.
• nonsteroidal anti-inflammatory drugs (NSAIDs).

1. Surgical removal

• of the infected vein may be necessary in some cases.

5. Fat emboli

• originate from bone marrow.
• enter the circulation through torn venules.

1. This may be associated with

• long-bone fractures.
• joint replacement surgery.

1. These cause

• direct occlusion of small blood vesselsin the lung, brain, and skin.

1. The embolic plugs generate

• toxic free-fatty acids and cause platelets to release serotonin.

1. Fat emboli syndrome results from severe cases of fat embolization.
2. This syndrome typically arises

• within 12–72 hours after injury.

1. Signs and symptoms include
2. Bergman's triad

• neurodysfunction(mild confusion with or without focal deficits)
• respiratory insufficiency(i.e., dyspnea and hyperoxemia)
• petechiae(on the axilla, chest, and proximal arms).

1. Fever and tachycardia
2. Laboratory studies may show

• fat dropletsin blood, urine, or sputum.
• elevated serum lipase or fatty acid levels.
• leukopenia and thrombocytopenia.
• hypoalbuminemia.
• hypocalcemia.

3. Treatmentis predominantly supportive (i.e., ABC's).

• Early fixation of long-bone fracturesis most important.

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4. Prognosis

• is proportional to the degree of pulmonary insufficiency.

1. Pressure sores and decubitus ulcers
2. Patients at high risk for developing pressure ulcers are

• critically ill.
• obese.
• immobile.

2. Ulcers occur most often

• near the sacrum in these patients.

3. Prevention

• Early mobilization and frequent position changes
• Adequate nutrition and proper hygiene

1. Global Complications
2. Fever

• is frequently present postoperatively.
• can represent an early sign of postoperative complications.

1. Body temperature

• higher than 38.5°C is common (40% of patients after major surgery).

2. The temporal relationship to the time of surgery

• is important (e.g., at ≤ 24 hours, a specific cause is found only 20% of the time).

3. The differential diagnosis

• of postoperative fever is found in Table 2-7.

4. Most fevers spontaneously resolvewithout treatment.
5. Risk factors that suggest an infectious cause for fever include

• preoperative history of trauma.
• American Society of Anesthesiologists (ASA) score higher than 2.
• fever after postoperative day 2.
• white blood cell count higher than 10,000 cells/dL.
• blood urea nitrogen (BUN) greater than 15 mg/dL.
• systemic manifestations (e.g., chills, rigors, erythema, induration).

6. Evaluation includes

• a thorough physical examination.
• laboratory studies.
• review of medicines for possible interactions.

1. Abnormalities of fluid balance, electrolytes, and acid-base disorders (see Chapter 7)

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Table 2-7. Differential Diagnosis of Postoperative Fever

Wind (pulmonary) Atelectasis, pneumonia, pulmonary emboli, sinusitis Water (urinary tract) Cystitis, pyelonephritis Walking Deep venous thrombosis Wonder drug (drug fever) β-Lactams (e.g., penicillins), sulfa derivatives, amphotericin B, phenytoin/barbiturates Wound Infections, abscess, anastomotic leaks, peritoneal hematoma Other Thrombophlebitis, adrenal insufficiency, thyroid storm/thyrotoxicosis, parotitis, intravenous catheter infection, pancreatitis, malignant hyperthermia, transfusion reaction, perirectal abscess

1. Complications of Minimal Access Surgery (Laparoscopy or Thoracoscopy)
2. Technique failures
3. Needle or trocar injury to a

• solid organ.
• hollow viscus.
• blood vessel.
• nerve.

2. Hypotension

• secondary to decreased venous return because of increased pressure within the abdomen.
• vena caval compression after insufflation of air.

3. Damage to adjacent organs

• when using heat-producing instruments(e.g., electrocautery, harmonic scalpel, lasers).

4. Extraperitoneal insufflation

• during attempted injection of air (e.g., CO₂or helium) into the peritoneal space.

5. Trocar site herniationor wound infection.
6. Rarely, an air embolus can occur

• if the pneumoperitoneum is inadvertently exposed to venous blood flow (i.e., large venous injury during the operation).

1. Pneumothorax

• can occur with insufflation of air into the peritoneal space especially with surgery near the diaphragmatic hiatus (e.g., Nissen fundoplication) [see Chapter 11].

1. A laparoscopic procedure

• should be converted to an open procedureif it cannot be completed safely or if a significant technique failure has occurred.

P.44

Review Test

Directions: Each of the numbered items or incomplete statements in this section is followed by answers or by completions of the statement. Select the ONE lettered answer or completion that is BEST in each case.

1. A 28-year-old man was involved in a high-speed motor vehicle accident where he sustained a closed comminuted left femur fracture. He subsequently underwent operative fixation by placement of an intramedullary nail. On postoperative day 2, the patient was noted to have dyspnea and fever (39.5°C). Other vital signs were a blood pressure of 136/74 mm Hg, pulse of 120 beats/min, respiration of 32/min. Oxygen saturations were 100% using a 40% face tent. The physical examination was significant for the patient being minimally arousable, having diffuse fine crackles on pulmonary auscultation, and widespread petechiae involving the axilla, chest, and upper arms. Which of the following statements most closely describes the above condition?

(A) An immediate pulmonary angiogram is both diagnostic and therapeutic for this condition

(B) Treatment of this condition requires rapid administration of cyclo-oxygenase inhibitors, fresh frozen plasma, and platelets

(C) Microscopic examination of blood, urine, and sputum may be helpful in making the diagnosis

(D) Early long-bone fracture fixation has little influence on the development of this condition

(E) The prognosis of this condition is proportional to the degree of renal insufficiency

1–C. Fat emboli originate from bone marrow and enter the circulation through torn venules, causing direct occlusion of small blood vessels in the lung, brain, and skin. The embolic plugs generate toxic free-fatty acids and cause platelets to release serotonin. Severe cases cause fat emboli syndrome, which has been described in trauma victims 12–72 hours after injury. Bergman's triad—neurodysfunction (mild confusion with or without focal deficits), respiratory insufficiency (dyspnea, hyperoxemia), and petechiae (axilla, chest, proximal arms)—as well as fever and tachycardia are seen. Fat droplets in the blood, urine, or sputum; elevated serum lipase or fatty acid levels; leukopenia or thrombocytopenia; and decreased serum albumin and calcium confirm the diagnosis. Treatment is predominantly supportive (e.g., positive pressure ventilation, increasing albumin, calcium), however early fixation of long-bone fractures is paramount. Prognosis is proportional to the degree of pulmonary insufficiency.

2. A 32-year-old man was recovering from acute necrotizing pancreatitis, which required operative débridement. On postoperative day 9 he had a large, melenic stool. Routine hematologic studies showed a drop in hematocrit from 32% to 26%. A nasogastric tube was placed, which returned minimal “coffee ground” residue (guaiac-positive) with a pH of 4.5. Which of the following statements is true regarding this patient's condition?

(A) Gastrointestinal protection should not routinely be instituted because of the side effects of mucosal-protective drugs

(B) Emergent exploratory laparotomy is indicated to quickly identify the source of bleeding

(C) Gastric ulcers are most likely present, necessitating immediate treatment for Helicobacter pylori

(D) Proton pump inhibition is an effective method for preventing this condition

(E) Upper and lower endoscopy have little role in identifying the source of bleeding

2–D. Mucosal inflammation and hemorrhage occurs frequently in severely ill and septic patients. Diffuse gastritis, duodenitis, and shallow ulcerations are often seen with endoscopy. If the ulceration involves large blood vessels, however, significant bleeding may occur. This is most likely caused by a breakdown of the protective mucosal barrier, rendering the intestinal lining susceptible to the corrosive acidic environment. Effective preventative measures include inhibiting acid production (e.g., histamine receptor antagonists, proton pump inhibitors) or augmenting the mucosal barrier (e.g., misoprostol, sucralfate [Carafate], antacids) because these agents have few side effects. Emergent laparotomy is not indicated unless medical management fails and the source of bleeding cannot be stopped by any other means (e.g., endoscopy, angiography). Although Helicobacter pylori is a known cause of gastrointestinal ulcer disease and bleeding, it has little influence on stress gastritis or duodenitis.

3. A 65-year-old man underwent an uneventful open inguinal herniorrhaphy, but during overnight observation was found to have vomited while he slept. He received aggressive suctioning but later that day he displayed a fever of 39.0°C. Other vital signs were a blood pressure of 140/70 mm Hg, pulse of 90 beats/min, and respiration of 24/min. Oxygen saturations were 92% with a 40% face tent. There were thick crackles on auscultation of the lungs. Chest radiograph was significant for bilateral infiltrates. Which of the following statements most accurately reflects the patient's current clinical condition?

(A) Cefazolin is the antibiotic of choice for treatment of this condition because of its activity against oral flora

(B) Pneumonias resulting from this condition are associated with minimal morbidity and mortality

(C) The left upper lobe is the most frequently involved pulmonary segment

(D) Nasogastric suction tubes and endotracheal tubes do not uniformly prevent this complication

(E) Bronchoscopy has little role in the diagnosis or treatment of this condition

3–D. Aspiration of abdominal contents into the lungs can be a serious complication associated with significant morbidity and mortality. The magnitude of lung injury is proportional to the volume, the frequency, and the pH of the aspirate. Risk factors include decreased sensorium (i.e., narcosis, stroke), nasogastric tube placement, intestinal obstruction, and pregnancy. The most commonly affected segments include the posterior right upper lobe, superior right lower lobe, or superior and posterior basal left lower lobes. Treatment involves re-establishment of the airway (if necessary), aggressive airway hygiene, and adequate fluid resuscitation. Although intubation is helpful, aspiration into the airway can still occur. Antibiotic use for large volume aspiration is controversial. However, pneumonia resulting from aspiration can be secondary to a variety of organisms and ideal antibiotic selection should be based on culture results. Bronchoscopy is an important tool for pulmonary hygiene and may be used if necessary.

4. During a routine postoperative check, a 67-year-old woman who had undergone resection of an infrarenal, abdominal aortic aneurysm complained of peri-incisional tenderness and some light-headedness. Her vital signs were a blood pressure of 110/40 mm Hg, pulse of 130 beats/min, respiration of 24/min, and temperature of 37.9°C. She had 25 mL urine output for the last 2 hours. On examination, she had dry mucus membranes, there were faint bibasilar crackles on pulmonary auscultation, her abdomen was mildly distended, the incisional dressing was clean and dry, and her feet were cool to the touch. Hematocrit dropped from 43% to 27%. Which of the following statements is true of her condition?

(A) These findings are suggestive of acute myocardial infarction with congestive heart failure

(B) Plain radiographs are the most sensitive imaging modality for determining the cause of abdominal pathology

(C) More potent narcotic analgesics may be helpful because her examination suggests a sympathetic nervous system response to poor postoperative pain control

(D) The presence of infection and sepsis is sufficient to explain all of the physical signs

(E) Operative exploration may be necessary if nonoperative measures fail to correct this condition

4–E. Hemoperitoneum is the most common cause of hypovolemic shock in the first 24 hours after abdominal surgery. Signs include low-grade fever, tachycardia, hypotension, oliguria, and peripheral vasoconstriction. The diagnosis is confirmed by demonstrating increasing anemia on routine hematologic tests. A computed tomography (CT) scan showing fluid in the abdomen consistent with blood may also be used if the clinical picture is questionable. Treatment consists of volume resuscitation, possible blood transfusion, correction of coagulopathy (if one exists), and re-operation with meticulous hemostasis if other measures fail. Although tachycardia is sometimes an indication of poor pain control, or infection and sepsis, there are enough other signs to quickly rule these out as the source of the current problem.

5. A 45-year-old, obese man was involved in a high-speed motor vehicle accident. He was hypotensive at the scene and was noted to have a distended abdomen upon presentation. He was quickly evaluated and taken to the operating room for an exploratory laparotomy. Which of the following is true with regard to adequate closure of the abdomen after this procedure?

(A) Permanent suture materials should not be used for closing the fascial layers because of the increased risk of local inflammation

(B) The instability of wound closure is decreased by the removal of devitalized tissue

(C) Body habitus and nutritional status are not important factors influencing wound stability

(D) Wound dehiscence is uncommon, although when it does occur it is usually during the first or second postoperative day

(E) Evisceration of the abdominal contents is a uniformly fatal event

5–B. Inadequate closure of fascial layers is the most important factor in determining the likelihood of dehiscence. Other important factors contributing to dehiscence events include increased intra-abdominal pressure (e.g., obesity, severe pulmonary disease, excess postoperative coughing, bowel obstruction, and cirrhosis with ascites formation) and deficient wound healing (e.g., infection, seroma or hematoma formation, drain placement, chronic disease, malnutrition, or chronic steroid use). Suture material for fascial closure should not be rapidly dissolvable because these layers are so important to wound integrity. Devitalized tissue predisposes to wound infection and should be eliminated. Dehiscence is a partial or total disruption of anatomic layers after surgical closure. Evisceration is wound dehiscence with the extrusion of abdominal contents. This is a highly morbid event, however not uniformly fatal. Treatment would consist of rapid wound coverage with sterile, moist towels, and emergent surgical exploration and repair.

6. A 53-year-old, obese woman with a history of Type II diabetes and chronic obstructive pulmonary disease (COPD) underwent mesh closure of an abdominal incisional hernia. She tolerated the procedure well and was discharged from the hospital the following morning. Which of the following factors would LEAST likely contribute to the incidence of postoperative complications in this patient?

(A) A small enterotomy made while dissecting the fascial layers was closed with dissolvable suture after minimal spillage of intestinal contents

(B) Her last hemoglobin A₁C was 11.7 and she has a history of an anaphylactic reaction to penicillin

(C) She is morbidly obese and has significant lower extremity claudication when attempting exercise

(D) She has end-stage COPD and her medications include prednisone 20 mg per day

(E) She had previously smoked 2 packs of cigarettes per day for 40 years, but has not smoked for the last 5 years

6–E. Factors contributing to most postoperative complications include the failure of operative techniques, the magnitude of the operation, the general medical condition of the patient, or chronic medications taken by the patient. The high hemoglobin A₁C level signifies poorly controlled diabetes. This may lead to poor wound healing. Obesity and peripheral vascular disease may be associated with cardiovascular complications and poor wound healing. Chronic steroid use may also lead to problems with wound healing, adrenal insufficiency, and immunosuppression. Moreover, COPD may predispose the patient to pulmonary complications. Smoking is a significant risk factor for postoperative complications, however not having smoked for over 5 years will significantly decrease the incidence of all complications, including pulmonary problems.

7. After an uneventful laparoscopic inguinal herniorrhaphy, a 58-year-old man had the urinary catheter removed and began to ambulate. During routine vital sign checks, he was noted to have had no urine output over the previous 8 hours. An intravenous bolus of saline (500 mL) did not stimulate voiding. Straight catheterization revealed 1000 mL of urine. Urinalysis showed a specific gravity of 1.018, a pH of 6, moderate blood, and negative leukocyte esterase and nitrites. There were 23 red blood cells/high power field (hpf) and 2 white blood cells/hpf. What is the most appropriate treatment for his failure to void?

(A) Catheterization and initiation of hemodialysis

(B) Catheterization and antibiotic administration

(C) Catheterization and administration of furosemide

(D) Catheterization and administration of mannitol

(E) Catheterization alone with continued observation

7–E. Postoperative urinary retention is a common problem especially after pelvic and perineal procedures or after spinal anesthesia. The causes in those cases appear to be interference with the normal autonomically mediated bladder emptying and overdistention of the bladder that inhibits contraction of the smooth muscle. Prevention of this includes catheterization of the bladder for long cases or for those where large volumes of intravenous fluids are used. Removing the bladder catheter and encouraging early postoperative voiding is also useful. If this is unsuccessful, in and out catheterization to decompress the bladder is used. The catheter should be left in place if the volume obtained is over 1000 mL. An indwelling catheter left for 4–5 days should be used if prior insertions were traumatic or if there is a continued inability to void. Formal urologic follow-up may be necessary.

8. A 75-year-old, obese woman with a history of insulin-dependent Type II diabetes mellitus underwent an uneventful laparoscopic cholecystectomy. She was slow to wake after the operation and was taken to the postoperative recovery unit intubated but breathing on her own. Vital signs were stable and all laboratory studies were within normal limits. Head computed tomography (CT) scan was interpreted as age-appropriate atrophy with no mass lesions or midline shift. She was taken to the intensive care unit where she slowly began to awaken over the next 48 hours. Which of the following most likely contributed to this patient's depressed level of consciousness postoperatively?

(A) Cerebrovascular accident

(B) Poor metabolism of anesthetics

(C) Acute myocardial infarction

(D) Hypoxic brain injury

(E) Hypoglycemic coma

8–B. Prolonged altered consciousness after general anesthesia may result from poor metabolism of anesthetic agents by the patient. Risk factors include advanced age, renal or hepatic insufficiency, and obesity. Other more serious events (e.g., hypoxic brain injury, diabetic coma, hypoglycemia) must be ruled out. Cerebral vascular accidents (e.g., strokes) may occur secondary to hypertensive, embolic, or thrombotic injury. After a cerebrovascular accident, patients may remain obtunded for up to 72 hours and then recover without neurologic deficits. Those with deficits, however, may have paralysis, abnormal reflexes, posturing, or convulsions. Treatment includes aspirin and anticoagulation if not contraindicated.

9. A 65-year-old woman with an open tibia/fibula fracture of her left lower extremity underwent uneventful débridement and external fixation. Her initial postoperative course was uneventful. On postoperative day 4, she was noted to have mild swelling of her left ankle and a fever of 38.6°C. Her wounds were without signs of infection and there were no palpable cords. Which of the following is the most likely cause of this patient's findings?

(A) Fat emboli

(B) Iatrogenic lymphatic disruption

(C) Thrombophlebitis

(D) Deep venous thrombosis

(E) Ascending lymphangitis

9–D. Deep venous thrombosis remains an important cause of postoperative morbidity because of the high prevalence and the potentially life-threatening consequences. Clot may propagate from the deep venous system of the lower leg into the femoral and iliac systems. Most pulmonary emboli originate from above the knee. Risk factors include Virchow's triad: vascular stasis (e.g., venous insufficiency, obesity), abnormal vessel walls (e.g., fractures), and hypercoagulability (e.g., estrogen therapy, pregnancy, cancer). Diagnosis is sometimes difficult because 50% of patients have no symptoms; the remainder have lower extremity swelling, fever, and pain as well as the classic positive Homan's sign characterized by calf pain with foot dorsiflexion. Fat emboli are not associated with ankle swelling. Iatrogenic lymphatic disruption is rare except with extensive resections of nodal groups. Thrombophlebitis typically presents with erythema, tenderness, and a palpable cord over the affected vein.

Directions: Each set of matching questions in this section consists of a list of four to twenty-six lettered options followed by several numbered items. For each numbered item, select the appropriate lettered option(s). Each lettered option may be selected once, more than once, or not at all.

Questions 10–12

1. Pneumonia
2. Pulmonary atelectasis
3. Fat emboli
4. Adult respiratory distress syndrome
5. Pneumothorax
6. Hemothorax
7. Pulmonary embolism
8. Air emboli

Select the most likely source of each patient's clinical problem.

10. A 16-year-old boy was diagnosed with acute appendicitis and subsequently underwent an uneventful laparoscopic appendectomy. He was admitted to the hospital overnight for observation. At 3:00 am, he was found to have a fever of 38.7°C. His examination was significant for bibasilar crackles and cough on deep inspiration. The surgical wounds were clean without signs of infection. (SELECT 1 SOURCE)

10–B. Atelectasis, or the partial collapse of alveoli, accounts for 90% of postoperative pulmonary complications and occurs most frequently in the first 48 hours after surgery. Closure of small (smaller than 1 mm) bronchioles leads to a ventilation/perfusion (V/Q) mismatch and subsequent hypoxemia. The mechanism of the febrile response remains unknown, however, but is usually self-limited. The diagnosis is made by both radiographic (e.g., characteristic discoid infiltrate, elevated hemidiaphragm) and physical examination signs, including scattered basilar crackles and decreased breath sounds.

11. A 52-year-old man underwent an orthotopic liver transplantation for cirrhosis secondary to hepatitis C. On postoperative day 4 the patient developed rapidly worsening respiratory failure secondary to presumed aspiration with diffuse airspace disease noted bilaterally on chest radiograph. On postoperative day 5 the patient underwent a liver biopsy for worsening liver function as well. The patient continues to deteriorate and rapidly develops hypotension refractory to volume resuscitation and pressors. On examination the patient is noted to have significantly decreased breath sounds on the right compared with the left, with hyperresonance to percussion. Diffuse crackles are noted on the left. (SELECT 1 SOURCE)

11–E. In critically ill patients all of these conditions can contribute to respiratory compromise and even hypotension. In patients with refractory hypotension in this setting, one should always consider tension pneumothorax as a potential cause. Pneumothorax is a potential complication of a liver biopsy because of the proximity of the lung and pleural space when passing the biopsy needle. Although a hemothorax can also occur, hyperresonance to percussion is suggestive of a pneumothorax.

12. A 32-year-old woman had a postgastric bypass for morbid obesity 6 days ago. Because of significant incisional pain, she was slow to ambulate. At 2:00 pm, while walking to the bathroom, she experienced sharp chest pain, cough, wheezing, hemoptysis, and syncope. Physical examination was significant for a pleural friction rub. Electrocardiogram was unchanged, but there was a wedge-shaped area of diminished pulmonary vascular markings at the periphery of her left lung. (SELECT 1 SOURCE)

12–G. Pulmonary embolism remains one of the most common causes of sudden death in hospitalized patients. Mechanical obstruction of the pulmonary arterial system occurs secondary to migration of a thromboembolus, usually from the deep venous system of the lower extremities. If the blockage is large enough, decreased cardiac output, hypotension, and impaired oxygenation caused by bronchospasm and vasospasm occur. Other signs include hemoptysis, pleural friction rub, new cardiac gallop, and electrocardiogram changes. Radiographically, diminished pulmonary vascular markings (Westermark's sign), pleural effusion, and a new pulmonary infiltrate may be present. Confirmation is possible with a ventilation/perfusion (V/Q) scan or pulmonary arteriogram.