Chapter 55: Postoperative Management After Specialty Surgery

This chapter discusses specific postoperative complications and management in the intensive care unit (ICU) after ENT, orthopedic, and urology surgery. Radical head and neck surgery with free-flap reconstruction, total hip replacement (THR) and total knee replacement (TKR), radical nephrectomy, and radical cystectomy are discussed.

Radical Head and Neck Surgery with Free-Flap Reconstruction

An estimated 55,000 Americans develop head and neck cancer mainly of the pharynx, larynx, and tongue annually and 12,000 die from the disease.¹ Radical head and neck dissection with free-flap reconstruction has evolved over the past 4 decades with free-flap success rates in the 90% to 99% range.

Otolaryngology patients with tumors of the head and neck undergo radical dissection and free-flap microsurgery. These patients are admitted postoperatively to the ICU for neurologic, free flap, and airway monitoring. Complications include flap failure, infections, postoperative bleeding, acute lung injury (noncardiogenic pulmonary edema), and venous thromboembolism (VTE). In addition to comorbid conditions such as chronic obstructive pulmonary disease (COPD) and diabetes, these patients often have a history of alcohol dependence and smoking, hence close monitoring for encephalopathy and alcohol withdrawal syndrome is warranted.

Surgical Factors

Radical head and neck dissection involves en bloc removal of all nodal groups between the mandible and the clavicle with removal of the sternocleidomastoid muscle, internal jugular vein, and spinal accessory nerve.

The free-flap transfer, also called a free tissue transfer, is an autologous transplantation of vascularized tissues that incorporate a direct cutaneous artery and vein in the base. The free flap may contain skin, muscle, bone, or fascia. Free flaps have a higher complication rate than skin grafts. Indications for free flaps include complex defects of the head and neck regions following tumor resection or chemoradiation, reconstruction in patients failing local or regional flaps, or failure of a prior free flap. Common sites of harvest include the anterolateral thigh, fibula, and iliac crest. Fascio-cutaneous flaps are used to repair superficial lesions; and muscle and myocutaneous flaps are used to repair deeper lesions. To reconstruct mandible and floor of the mouth defects, fibular free flaps with overlying skin, or iliac crest bone flaps are usually used.

Patient Risk Factors

Diabetics are at increased risk of flap failure secondary to microangiopathy, increased risk of thrombosis and wound infection. Increasing age is an independent risk factor and smoking is associated with injury to flap vessels causing intimal fibrosis and potentially poorer outcomes.

Postoperative Management

Airway Monitoring

Anatomical changes occur in head and neck cancers that may create a difficult airway. Close monitoring for postoperative airway compromise after head and neck surgery in the ICU is warranted due to complications including soft-tissue edema, bleeding, hematoma, and bilateral laryngeal nerve damage. Securing the airway in head and neck reconstructions may be difficult hence caution should be exercised before extubation. Postoperative soft-tissue edema peaks around the second or third postoperative day.

Once the patient tolerates a spontaneous breathing trial, a cuff-leak test should be considered before extubation. Two cuff-leak methods exist. The qualitative method is listening for air movement with a stethoscope after deflating the endotracheal tube balloon. In the quantitative method the endotracheal balloon is deflated while on volume control ventilation and the difference between the inspired versus expired tidal volume is measured. An at least 110 mL difference or a decrease of 12% to 24% in the expired versus inspired tidal volume supports adequate leakage around the tube and hence less airway edema.² However, none of these tests are highly predictive of extubation success or failure and are only adjuncts to the overall clinical assessment.

In the event of respiratory distress or lack of an air-leak, extubation should be deferred for the next 24 hours. Inspection via laryngoscope may be performed to assess airway edema while the patient is still intubated. Steroids may be used in some cases for soft-tissue edema to facilitate extubation.

Intensivists should be prepared for emergent endotracheal intubation or an emergent surgical airway. Anesthesiologists and ENT surgeons should be present at bedside or in close proximity during extubation. Emergent airway equipment should remain at bedside with ENT surgeons on standby to perform emergent bedside tracheostomy if necessary.

In patients with extensive head and neck reconstructions a concomitant tracheostomy is usually done at the time of surgery to overcome airway compromise. Elective tracheostomy is recommended for patients with a high risk of airway obstruction. Multiple scoring systems for elective tracheostomy in head and neck cancer patients have been developed based on various parameters that include tumor size, tumor localization (involving larynx, base of the tongue, pharynx) TNM (tumor, nodes, metastases) staging, mandibulectomy, neck dissection, pathological chest X-ray findings, multiple comorbidities (mostly cardiopulmonary), and chronic alcohol dependence.^3,4 However, there is no gold standard scoring system for determining elective tracheostomy and so clinical judgment is required.

Respiratory Failure

Comorbid conditions such as underlying lung disease, cardiovascular disease, renal disease, alcohol abuse, and malnutrition are significant risk factors for failure to wean from mechanical ventilation.

Fluid Resuscitation

Free-flap tissues can become ischemic and can be sensitive to ischemia/reperfusion injury with different responses to hypotension or vasopressors. Balanced volume resuscitation is very important in microsurgery, because volume overload is associated with flap edema and compromising flap microcirculation. Given the small caliber of blood vessels, hypotension should be avoided because even minimal vasoconstriction in the flap microcirculation leads to decreased blood flow. Low-molecular-weight (LMW) dextran (eg, Dextran 40) is used at some centers because of its rheological properties in reducing viscosity and providing antithrombotic effects thus potentially improving blood flow in the free flap. Increased risk of flap edema and acute lung injury/noncardiogenic pulmonary edema may occur more often in patients receiving higher volume crystalloid administration, for example, more than 130 mL/kg in 24 hours or more than 7 liters intraoperatively as reported in 1 study.⁵

Vasopressors

Vasopressors have been used in clinical practice to increase the mean arterial pressure (MAP) and improve perfusion pressure across the free flap. In a recent study of patients undergoing free flaps receiving mainly phenylephrine or ephedrine, there was no significant relationship between intraoperative vasopressor and major free-flap complications.⁶ Prospective studies on the postoperative use of vasopressors have shown that norepinephrine and dobutamine can improve free-flap skin blood flow, with the greatest benefit from norepinephrine. Other pressors such as dopamine and epinephrine decreased flap flow.^6,7,8 The use of albumin over synthetic colloids to replace intraoperative blood loss has not proven to be beneficial to date. However, the judicious use of pressors in an adequately volume resuscitated patient using norepinephrine is advised; there is no added benefit to use dobutamine which may lead to tachycardia, tachyarrhythmias, and hypotension.

Myocardial Infarction

Coronary ischemia and hemodynamic instability play an important role in flap outcomes. Long-term smoking and tobacco abuse not only increase the risk for cancer but also increase the risk of coronary artery disease (CAD) and myocardial infarction (MI). The risk of MI in the perioperative period is low, but associated with high mortality. High-risk patients with preexisting renal insufficiency, CAD, peripheral vascular disease (PVD), congestive heart failure (CHF), age of above 74, hypertension and prior chemoradiation are at increased risk for troponin elevation in the first 24 hours. Monitoring of troponin levels and the EKG is important in the immediate postoperative period. Elevated troponins post-ENT cancer surgery are associated with an 8 fold increased risk of death.⁹

Harvest Sites

Harvest sites need to be monitored frequently for signs of bleeding, hematoma, ischemia, or infection.

Microvascular Thrombosis

The reexploration rate after free-flap surgery due to circulatory compromise is about 5% to 25%. The success of the flap transfer is inversely proportional to its ischemic time and time to recognition of complications. Venous compromise occurs more often than arterial compromise and is usually seen in the first 2 or 3 postoperative days, while arterial compromise usually occurs later.^10,11 Flaps complicated by postoperative hematomas require early evacuation to avoid vascular pedicle compression and flap engorgement. Good surgical technique, close flap monitoring, and early recognition of flap compromise are the keys to free-flap transfer success.

Data on the success rate of free-flap salvage within the first 1 to 4 hours following vascular compromise are close to 100%, but the success rate drops to 70% to 80% for ischemia times of more than 4 to 8 hours. If circulatory compromise is not addressed within 8 to 12 hours there may be development of no-reflow phenomenon¹² where restoration of blood flow results in initial hyperemia with free-oxygen radicals and complement system activation followed reperfusion injury, a gradual decline in perfusion and cell death.

Flap Monitoring

Flap color, temperature monitoring, color duplex, Doppler ultrasound, and pin-prick testing are a few of the monitoring modalities,¹³ but no ideal or gold standard exists. Clinical evaluation and color duplex Doppler has been proven to be more accurate in diagnosing vascular compromise of free-flap transfers.¹⁴ In the first 24 hours, patients are closely monitored in the ICU, kept nil per os (NPO) and are on strict bed rest to prevent potential complications in the event that reexploration is required. Flap checks are initially done half-hourly or hourly to assess flap viability. Avoidance of hypotension, hypoxia, and hypothermia are important. Venous congestion and necrosis in the skin paddle of a free flap might result in loss of the flap. Venous flow can be preserved by using systemic heparin therapy, LMW dextran or medicinal leech therapy.

Clinical observation of flap color, swelling, temperature, and capillary refill remains a vital mode of monitoring. A healthy and a well-perfused flap appears pink, minimally swollen, and warm to touch; a congested flap appears bluish in color, swollen, warm to touch with a short capillary refill time of less than 2 seconds. If the flap is ischemic it appears pale, cold to touch with a delayed capillary refill time of more than 3 seconds. Upon puncturing a viable free flap with a small gauge needle (pin-prick test) bright red blood flows immediately, whereas in a congested flap the blood flow is dark suggesting compromise. This test is usually performed on flaps where clinical monitoring by visualization is difficult. In pharyngoesophageal reconstruction using small intestine, the sentinel loop that is left outside the neck is used to monitor the viability. A healthy intestinal graft is pink and warm with minimal swelling and visible peristalsis; loss of peristalsis suggests graft compromise.

Compression of the artery will lead to loss of the Doppler signal within the flap, whereas venous compression will lead to augmentation of the venous signal due to increased venous return. Implantable Doppler probes may be used to monitor the flow in buried flaps. A decrease in tissue oxygen partial pressure (ptiO₂) monitoring via an implantable oxygen-monitoring probe (eg, Licox) may suggest free-flap compromise. A pitfall of these monitors is that the probes are localized and do not assess viability outside the small sample volume that is monitored.

Microvascular Flap Anticoagulation

Aspirin and LMW heparin alone or in combination are commonly used for postoperative anticoagulation after free tissue transfer. Other strategies to prevent thrombosis include decreasing blood viscosity by LMW dextran infusions and/or hemodilution with IV fluids and avoiding blood-product transfusions unless absolutely necessary. LMW dextran antithrombotic properties are not fully understood but are thought to be secondary to platelet function impairment, destabilizing fibrin, and prolonging bleeding time. Studies report variable efficacy of these anticoagulants in preventing free-flap thrombosis.

Complications of LMW Dextran—Dextran has significant dose-dependent adverse affects. These include anaphylaxis, a rare but potentially life-threatening complication,^15,16 noncardiogenic pulmonary edema, renal insufficiency, and rarely cardiac arrest.

Dextran infusion syndrome should be suspected in patients on LMW dextran that develop noncardiogenic pulmonary edema. They may also develop hypotension, bronchospasm, or coagulopathy. The incidence increases with higher infusion rates and the longer the infusion continues. The treatment is prompt discontinuation of the dextran infusion and initiating symptomatic treatment.

Hirudotherapy—Medicinal leech therapy, called hirudotherapy is commonly used in the setting of free-flap venous congestion or thrombosis to temporarily establish venous outflow until neovascularization of the graft is established. Leeches produce an anticoagulant called hirudin that is a selective thrombin inhibitor; it also secretes vasodilators and hyaluronidase that allow the leech to ingest blood. The regimen is to use about 2 to 4 leeches depending on the size of the flap, attached to the tissue for approximately 20 minutes. Following the leech therapy, blood oozes for the next 24 hours. Complications from this therapy include bleeding, anemia, leech migration to a different body location, and rarely local or systemic infection with the gram-negative bacillus Aeromonas hydrophila.¹⁷

Blood Transfusion

There are no clear transfusion thresholds in free-flap surgery; however, it appears that a restrictive transfusion strategy using a postoperative transfusion trigger of hematocrit of less than 25 is not inferior to a higher transfusion threshold of hematocrit of less than 30 in patients undergoing free-flap surgery, with no increase in flap-related complications in the lower transfusion trigger group.¹⁸

Wound Infection

Wound infection is not uncommon in tissue transfer surgery involving head and neck tumors. Risk factors for infection include preoperative radiotherapy, blood transfusion, smoking, and the duration of surgery.

Alcohol Withdrawal

The overall flap survival rate with alcohol withdrawal syndrome (AWS) is about 83%. Patients with postoperative AWS have a higher chance of developing non-flap-related complications, especially respiratory problems (prolonged ventilator dependency), encephalopathy, seizures, and hemodynamic instability. The onset of alcohol withdrawal symptoms is usually 1 to 2 days after abstinence (delirium tremens may occur at 2-5 days). Once AWS signs are recognized, prompt treatment should commence with an initial regimen of parenteral thiamine, multivitamins, and folic acid supplements. Effective treatment for AWS involves treatment with benzodiazepines and occasionally antipsychotics.¹⁹ As more data become available, dexmedetomidine appears promising in the treatment of AWS.

This section reviews critical-care management after THR and TKR.

Admission rates of orthopedic patients to the ICU are rising due to an increasingly elderly population. Approximately 1 of 30 patients undergoing total joint arthroplasty will require critical-care monitoring. Identifying high-risk patients undergoing joint replacement for adverse events and monitoring in ICU can optimize outcome and reduce morbidity and mortality.

Risk factors for requiring critical-care services include advanced age, hip versus knee surgery, general anesthesia, multiple comorbidities, intraoperative or postoperative complications, and surgical indications other than osteoarthritis and rheumatoid arthritis. Smoking is associated with significantly higher perioperative complications and mortality following total hip arthroplasty and total knee arthroplasty.

Surgical Factors

In THR and TKR, the damaged articular cartilage over the bone surfaces is replaced. The bone is cut based on preoperative radiographs and anatomic measurements. These cut bony surfaces are covered by metal, ceramic, or polyethylene components that are sized appropriately to match the alignment, leg length, and range of motion. If all compartments and surfaces of the joint are replaced, the procedure is referred to as a total joint arthroplasty/replacement. If only 1 surface or compartment of the joint is replaced, it is referred to as hemiarthroplasty. In total hip arthroplasty both the femoral head and neck are replaced. In total knee arthroplasty the distal femur, tibia, and patella are resurfaced after any remaining articular cartilage and a layer of subchondral bone are resected.

Blood Transfusion Criteria

Total hip and total knee arthroplasty frequently require blood transfusion with transfusion rates ranging from 18% to 68%. The Function and Overall Cognition in Ultra-High Risk States (FOCUS), largest trial, to address blood transfusion threshold in hip fracture patients suggests that mortality, length of stay, are no different from the general population with a restrictive transfusion threshold of hemoglobin 8 g/dL.²⁰

Cardiopulmonary Complications

Risk factors for developing postoperative cardiac complications include age of 80 years or above, hypertension requiring medication and history of cardiac disease. The cardiac complication rate is approximately 0.33% after total knee arthroplasty or total hip arthroplasty. Serious complications such as MI and cardiac arrest constitute 7% to 20% of all major complications. Patients with underlying cardiac disease who receive large volume resuscitation and blood products are at increased risk of noncardiogenic pulmonary edema and supraventricular arrhythmias such as atrial fibrillation and atrial flutter. Risk factors for perioperative development of supraventricular arrhythmias include a history of atrial fibrillation, increasing age, left anterior hemiblock, and atrial premature depolarizations on the preoperative electrocardiogram. In patients aged above 60 years with any one of the above risk factors, the risk of arrhythmia is as high as 18%.²¹ Electrolyte abnormalities, hypoxia, and acidosis should be corrected.

Respiratory Failure

Occurrence of postoperative pneumonia is high in elderly patients; atelectasis and secretions, intubation, reintubation, prolonged ventilator support, and use of preoperative proton pump inhibitor use are risk factors for developing pneumonia. The rate of serious pulmonary complications has been reported to be 2.6%, with a 30-day mortality of 17%. Risk factors for developing acute respiratory distress syndrome (ARDS) include aspiration, blood-product administration (including transfusion-related acute lung injury [TRALI]), and lung injury from fat embolism or bone cement, surgical site infection, and sepsis. The mortality rate is approximately 60% in elderly patients above 85 years. Treatment includes supportive care and lung-protective ventilation strategies.

Fat Embolism Syndrome

Fat embolism is defined as occlusion of the microcirculation by presence of fat globules. Common causes of fat embolism syndrome (FES) include orthopedic trauma, particularly involving long-bone fractures in the lower extremity and orthopedic surgeries involving the lower extremity. The incidence of asymptomatic fat embolism in THR and TKR is approximately 46% to 65%.

The development of FES may be secondary to extravasation of fat globules from the bone marrow during the surgical procedure secondary to increased intramedullary pressure. Clinically, the classic triad of FES is hypoxemia, neurological abnormalities (eg, agitated or hypoactive delirium), and petechiae. Occasionally severe cases of FES can be complicated by disseminated intravascular coagulation, right ventricular dysfunction, biventricular failure, ARDS, shock, and death. No gold standard criteria exist to diagnose fat embolism. The incidence of FES thus varies widely. The most frequently used diagnostic criteria are Gurd's criteria (Table 55–1).

Given the systemic complications, high-risk patients need close monitoring. No clear treatment guidelines exist; supportive care with fluid resuscitation and mechanical ventilation are the main stays. Heparin and corticosteroids have not been found to improve morbidity or mortality.^21,22

Bone Cement Implantation Syndrome

Bone cement implantation syndrome (BCIS) is a life-threatening complication of orthopedic surgery characterized by hypoxia, hypotension, pulmonary hypertension, arrhythmias, loss of consciousness, and potentially cardiac arrest occurring around the time of bone cementation.²³ Complications from acrylic bone cement polymethylmethacrylate (PMMA) have been recognized as early as the 1970s, but recently have been more frequently reported. The majority of complications develop soon after the application of cement or in the immediate postoperative period. Patient risk factors include advanced age, malignancy, osteoporotic bones, renal failure, congestive heart failure, chronic obstructive lung disease, use of diuretics, and angiotensin converting enzyme medications. BCIS increases the 30-day mortality rate by 16 fold.

The pathophysiology is not fully understood but may be secondary to the release of inflammatory markers, anaphylaxis and complement activation leading to increased pulmonary vascular resistance causing ventilation/perfusion disturbances and right ventricular failure. Recently, BCIS has been classified into 3 grades depending on the severity (Table 55–2).²⁴

The incidence of BCIS may be reduced by use of noncemented joints, high-volume medullary lavage, intraoperative canal suctioning during cementation, low-viscosity PMMA, and slow controlled insertion of the prosthesis. Use of tobramycin-impregnated bone cement decreases the incidence of BCIS but is associated with acute kidney injury (AKI) in patients with underlying renal disease.

ICU admission is warranted in patients with hypotension, hypoxemia, anaphylactic reactions, and right heart failure after undergoing cement joint replacement. Transthoracic echocardiography should be considered in these patients to assess cardiac activity especially, right ventricular function. In patients with hemodynamic instability, fluid resuscitation and vasopressor support should be provided. Patients with symptomatic hypoxia or ARDS should be supported by lung protective mechanical ventilation.

Venous Thromboembolism

The rate of pulmonary embolism (PE) in the nonorthopedic population aged above 65 years is approximately 0.03%, but patients undergoing THR or TKR have a 10 fold or 0.3% increase in PE. Risk factors for VTE are increasing age, immobilization, presence of varicose veins, previous deep vein thrombosis (DVT), smoking, hormonal therapy, location of surgery (knee > hip) malignancy, type of anesthesia, indwelling venous catheters or pacemaker, surgical time, and joint replacement itself. High-risk patients with evidence of right ventricular dysfunction clinically or echocardiographically are at risk of shock or death and need close ICU monitoring (Table 55–3).

The latest (9th) American College of Chest Physician (ACCP) guidelines from 2012 suggest initiating VTE prophylaxis 12 or more hours preoperatively or postoperatively rather than 4 hours or less preoperatively or postoperatively. LMW heparin is preferred prophylaxis for a minimum of 10 to 14 days along with intermittent pneumatic compression devices. Patients with active signs of bleeding are recommended to receive mechanical VTE prophylaxis. Current evidence does not provide clear guidance about inserting prophylactic inferior vena cava (IVC) filters in patients undergoing elective hip and knee arthroplasty with contraindications to chemoprophylaxis or residual venous thromboembolic disease. Orthopedic surgeons should be consulted prior to initiation of VTE prophylaxis in these patients at all times, especially in patients with acute blood loss anemia requiring ICU admission. Formal discussion with the primary team regarding VTE prophylaxis should be incorporated into team rounds.

Most patients undergoing radical nephrectomy and cystectomy do not require intensive care monitoring unless they develop perioperative complications such as hemodynamic instability (from acute blood loss, splenic injury, MI, adrenal insufficiency (AI), hypovolemia, pulmonary embolism) and respiratory failure.

Radical Nephrectomy

Renal cell carcinoma (RCC) is the third most common cancer of urinary tract and accounts for 80% to 85% of all primary renal neoplasms, with an annual incidence of over 60,000 in the United States. One third of newly diagnosed patients with RCC present with advanced stage (III/IV) tumors.

Surgical Factors

Radical nephrectomy includes removal of the kidney and Gerota's fascia, ligation of the renal artery and vein, and occasionally removal of the ipsilateral adrenal gland. This procedure is usually done laparoscopically for renal masses smaller than 4 cm, whereas open radical nephrectomy is reserved for large, locally advanced tumors, caval extension, or enlarged lymph nodes.

Complications

In a retrospective analysis from the National Surgical Quality Improvement Program (NSQIP), cystectomy had the highest morbidity (3.2% mortality), followed by nephrectomy, retroperitoneal lymph node dissection, and radical retropubic prostatectomy. Postoperative complications following radical nephrectomy include postoperative bleeding, pneumothorax (PTX), MI, liver injury, pancreatic and splenic injury.

Hypotension is not uncommon in the postoperative period from blood loss, dehydration, and sedation. Prompt recognition of bleeding, achieving hemostasis, fluid resuscitation to maintain intravascular volume and tissue perfusion, MAP greater than 65 and avoidance of fluid overload are the mainstays of treatment.

PTX may occur with surgeries involving the flank; rib resection is not always necessary to cause PTX. In the event of postoperative respiratory or hemodynamic instability, the diagnosis of PTX must be considered. Physical examination, ultrasound, and chest radiography are methods to determine the diagnosis.

The adrenal gland is a highly vascular structure and is occasionally removed during radical nephrectomy. There is no difference in the survival of patients undergoing radical nephrectomy with or without adrenalectomy, whereas in metastatic disease the survival is poor, independent of adrenalectomy. Monitoring for signs and symptoms of acute Addisonian crisis is important. AI is characterized by hypotension, fever, hyperkalemia, hypoglycemia, weakness, and nausea or vomiting. However, signs of AI may not always be seen in ICU patients who usually present with refractive hypotension with or without hypoglycemia; therefore, a low threshold for the diagnosis of AI is warranted. This is a medical emergency and needs to be treated promptly with corticosteroids without waiting for cortisol levels or an adrenocorticotropic hormone (ACTH) stimulation test.

Left radical nephrectomy is the second most common cause of splenic injury. The incidence is approximately 4.3% to 13.2% and is higher during transperitoneal approach compared to retroperitoneal approach. Common signs and symptoms in an awake patient are abdominal pain, hematocrit drop, hypotension, and Kehr sign (referred pain at left shoulder tip), but these signs may not be recognized in less responsive patients. Splenic injury should be considered in the event of unexplained hypotension or hematocrit drop postnephrectomy. Bedside, ultrasonography can be utilized to quickly diagnose splenic injury in hemodynamically unstable patients (perisplenic fluid or intraperitoneal fluid seen in Morrison's pouch). Splenic injury can be also diagnosed by computed tomography. Nonoperative management of splenic injury includes aggressive volume and blood-product resuscitation and supportive care to keep the hemoglobin greater than 7.0 g/dL. Surgical treatment includes angiography and embolization or emergency splenectomy. Other important differentials for postoperative hemodynamic instability include hypovolemia, acute blood loss, sepsis, acute coronary syndrome, and pulmonary embolism.

Left radical nephrectomy can result in pancreatic injury and bleeding, hence follow up with lipase; amylase and abdominal imaging should be considered in suspected patients. The risk factors for VTE include poor functional status, age of above 60 years, anesthesia time more than 2 hours, steroid usage, metastatic disease, and congestive heart failure.

Patients with underlying chronic kidney disease (CKD) are at increased risk of developing AKI. The overall incidence of AKI in patients undergoing radical or partial nephrectomy is approximately 7%. Sepsis, urinary obstruction, and bleeding are leading causes of AKI in these patients. The overall mortality increases with severity of AKI (4.8% in stage 1, 9.1% in stage 2, 14.9% in stage 3).

Radical Cystectomy and Urinary Diversion

Open radical cystectomy (ORC) remains the standard treatment for high-grade nonmetastatic invasive bladder cancer. Multiple centers have adopted new operative techniques such as robotic assisted radical cystectomy (RARC) that has increased from 0.6% of all cystectomies in 2004 to 12.8% in 2010.²⁵

Surgical Factors

Radical cystectomy involves removal of the bladder, adjacent organs, and regional lymph nodes. In males, radical cystectomy includes removal of the prostate, seminal vesicles, along with the urinary bladder. Advances such as laparoscopic cystectomy and RARC have resulted in technical improvements resulting in less blood loss, fewer blood transfusions, reduced risk of complications and shorter hospital stay, as compared with open surgery.

Using the NSQIP database, the rates of DVT and PE (4.0% and 2.9%) were found to be the highest after cystectomy and urinary diversion^26,27 followed by nephrectomy and prostatectomy. Cystectomy is an independent risk factor for VTE; other risk factors include increased body mass index (BMI), positive surgical margins, older age, and increased length of stay. ACCP guidelines, suggest 4 weeks of low-molecular-weight heparin for VTE prophylaxis in patients at high risk who undergo abdominal and pelvic surgeries.

Gastrointestinal events represent the majority of complications following radical cystectomy with ileal conduit. Intestinal obstruction is most common (23%), followed by ileus (18%) and intestinal anastomotic leakage (3%) in a recent series.²⁸ Special monitoring is necessary to detect signs and symptoms of urosepsis, urinary leak, and pyelonephritis following urinary diversion surgery.

The use of balanced crystalloid solutions (Plasmalyte, Lactated Ringer's) in patients undergoing radical cystectomy with ileal conduit is preferred over normal saline because 0.9% sodium chloride solution is associated with hyperchloremic metabolic acidosis. Hypervolemia can result in interstitial edema causing deleterious effects on bowel function. One recent report suggested that restrictive fluid administration and preemptive use of norepinephrine to correct hypotension might be beneficial in decreasing postoperative complications.

Infectious events constitute about 25% and are the second most common complications of radical cystectomy according to a recent investigation.²⁸ Antibiotic prophylaxis (eg, ampicillin) is given for radical cystectomy. Major infections that are encountered following radical cystectomy are urinary tract infection, urosepsis, pyelonephritis, and sepsis. Wound-related complications in the early postoperative period include primary dehiscence and infection.²⁹

Urinary diversion is a surgical procedure in which the urinary flow is rerouted from the bladder.³⁰ Different types of diversion include ileal conduit, continent cutaneous diversion, and orthotopic neobladder (the urine is eliminated by the urethra). Potential complications following urinary diversion include AKI, hydronephrosis, urinary tract infection, nephrolithiasis, and metabolic disturbances. Mucus is often produced by urinary reservoirs and bladder substitutes; hence frequent irrigation of mucus is necessary to avoid mucus accumulation and infection.³¹ Orthotopic diversion is a significant predictor of VTE compared to nonorthotropic diversion.

Radical cystectomy often leads to considerable blood loss with an average blood loss of 560 to 3000 mL.