Long-Term Complications and Management

Key Points

1.
Cardiac surgical patients are at significant risk from preventable adverse events. These events occur through human error, by either faulty decision making (diagnosis, decision for treatment) or faulty actions (failure to implement the plan correctly).
2.
Human error is ubiquitous and cannot be prevented or eliminated by trying harder or by eliminating the one who errs. Reduction in human error requires system changes that prevent errors from occurring (forcing functions) or prevent errors from reaching the patient.
3.
Sleep deprivation and fatigue can render a person more likely to make an error. Although residents' hours are limited, those of other physicians in the United States are not, unlike in other countries.
4.
Nontechnical skills such as leadership, communication, cooperation, and situational awareness are critical to patient safety, but they are rarely taught. Distractions, disruptions, noise, and alarms contribute to technical errors and increase mortality rates in cardiac surgery.
5.
Communication is the leading root cause of sentinel events, whether through missing information or through misunderstanding. Use of structured communication protocols reduces errors. Handoffs performed without a protocol involve significant numbers of omitted items.
6.
Team training reduces surgical mortality rates, but it must be done with careful preparation and with regular retraining.
7.
Surgical briefings that use a checklist significantly reduce surgical mortality rates (“World Health Organization Safe Surgery Saves Lives”). Debriefings allow teams to identify hazards and formulate improvements.
8.
Simulation is an effective means to teach both technical and nontechnical skills and to allow teams to train for rare but dangerous events.
9.
Cognitive aids should be available in every operating room to provide direction during rare crisis events (eg, malignant hyperthermia, pulseless electrical activity).
10.
Medication errors occur approximately in 1 in every 150 to 200 anesthetic cases. The Anesthesia Patient Safety Foundation published a set of recommendations to reduce medication errors, including standardization, use of technology such as bar codes and smart infusion pumps, having pharmacy involvement in every step of the medication process, and building a culture of safety.
11.
Awareness during anesthesia occurs approximately 1 to 2 times per 1000 anesthetic cases, and it occurs more often in cardiac surgical procedures. Use of a processed electroencephalogram or achieving an end-tidal concentration of 0.7 minimum alveolar concentration is effective in reducing the incidence of awareness.
12.
The culture of an organization or a unit contributes significantly to patient safety or danger. Strict hierarchical cultures typically harbor a culture of blame and shame, which inhibits identification and correction of hazards. A “Just Culture” acknowledges that human error occurs and seeks to redesign the system to prevent future errors, but also holds individual persons accountable for willful violations.

This chapter focuses on the long-term complications and management of patients after cardiac surgery in the intensive care unit (ICU) and includes a discussion of specific infections observed in patients after surgery, the management of acute renal failure, and the role of nutritional support in the critically ill. The chapter also covers complications after newer surgical procedures such as transcatheter aortic valve replacement (TAVR), other minimally, invasive hybrid procedures, and long-term complications of ventricular assist devices (VADs) and extracorporeal membrane oxygenation (ECMO). Finally, this chapter concludes with an overview of the numerous ethical dilemmas that this technology has created for patients, families, and clinicians.

Infections After Cardiac Surgery

Device-Related Infections

Cardiac-Implanted Electronic Devices

As the number of cardiac-implanted electronic devices (CIEDs; eg, pacemakers, cardioverter-defibrillators, cardiac resynchronization therapy) is gradually increasing, their complications, such as infections, are also increasing. CIED-related infections can be difficult to diagnose since echocardiography is less accurate and blood cultures are less sensitive than in endocarditis. Most of the patients exhibit nonspecific symptoms, and fewer than 10% of the patients develop septic shock. The incidence of CIED-related infections varies among studies from between 0.5% and 2.2%, with a twofold to fivefold increase in incidence after a revision. The most common pathogens identified across different studies were staphylococci and other gram-positive bacteria. All-cause mortality associated with CIED-related infection varied between 0% and 35%.

The management of suspected CIED-related infections, including the number and sequence of blood cultures and antibiotic therapy, should be guided by the clinical severity. The treatment recommendations for definite CIED-related infections include early removal of the entire system (ie, all leads and generator) along with appropriate antibiotic therapy.

Ventricular Assist Devices

Left ventricular assist device (LVAD) driveline-related infections occur with an incidence up to 20% and commonly develop more than 30 days after implantation. Infections in patients with LVADs are associated with increased hospitalization, frequent need for reoperation, increased risk of stroke, and delay in heart transplantation. Some authors report a trend toward decreased survival in patients with an LVAD who develop infections.

Patients with LVAD infections tend to have a larger body mass index and frequently have a history of diabetes mellitus. Staphylococcus aureus was the most common organism identified in patients with an LVAD and with sepsis complications. The management of LVAD driveline-related infections potentially requires driveline repositioning or LVAD exchange with antibiotic bead implantation and systemic antibiotic treatment.

Intravascular Devices

Intravascular devices such as arterial, central venous, or pulmonary artery catheters are universally used in patients after cardiac surgery. Patients who have intravascular catheters often acquire bloodstream infections (BSIs), which are associated with prolonged hospitalization and increased risk of mortality. Central line–associated BSI (CLABSI) is defined by the Centers for Disease Control and Prevention (CDC) as bacteremia not related to an infection at another site or two or more positive blood cultures with a common skin contaminant associated with signs and symptoms of infection. CLABSIs are prevalent worldwide, and the rate is almost fourfold higher internationally (7.6 per 1000 central-line days) than the national rate in the United States (2 per 1000 central-line days). The CDC reported a significant reduction of CLABSI incidence in ICUs in the United States in recent years: a 58% reduction from 2001 to 2009. The risk of a BSI for arterial catheters is lower than the risk associated with noncoated, uncuffed, nontunneled short-term central vascular catheters (1.7 vs 2.7 per 1000 catheter days). If arterial catheters are inserted using maximum barrier precautions, then a very low risk of BSIs (0.41 per 1000 catheter days) can be achieved.

The recognized risk factors for the development of CLABSIs were prolonged hospitalization before catheter insertion, femoral and internal jugular catheterization, longer catheterization duration, neutropenia, use of total parenteral nutrition, extensive catheter manipulation, and reduced nurse-to-patient ratio. The majority of CLABSI cases are caused by gram-positive organisms (60%), including coagulase-negative staphylococci (34%), the Enterococcus species (16%), and Staphylococcus aureus (10%); approximately 18% of the reported CLABSI cases were attributable to gram-negative organisms (18%) and to the Candida species (12%).

The prominent reduction of the CLABSI rate with the implementation of various prevention initiatives has prompted the development of many quality improvement initiatives with the goal to achieve a minimum-to-none CLABSI incidence. The CDC published guidelines for the prevention of catheter-related infections (CRIs) in 2011. The summary of the guidelines is presented in Box 32.1 .

Box 32.1

Adapted from O'Grady NP, Alexander M, Burns LA, et al. Guidelines for the prevention of intravascular catheter-related infections. Am J Infect Control. 2011;39(4 Suppl 1):S1–S34.

Prevention of Intravascular Catheter–Related Infections

Central Venous Catheter Infection Prevention

Use the subclavian site if possible, and avoid using the femoral site
Use ultrasound, if available, to reduce the number of imaging attempts
Use the catheter with the minimum number of lumens necessary
Use strict hand hygiene, skin preparation with an antiseptic, and full barrier precaution for insertion
Maintain aseptic technique through the insertion and care of the catheter
Regularly monitor the catheter insertion site for signs of infection
Use 2% chlorhexidine for daily skin cleansing
Do not routinely replace the catheter to prevent infection
Do not use guidewire to exchange the catheter in case of suspected infection
Remove the catheter when it is no longer necessary

Arterial Catheter Infection Prevention

In adults, radial, brachial, and dorsalis pedis are preferred over axillary and femoral sites
Use a minimum of cap, mask, sterile gloves for arterial catheter insertion, and full barrier precautions for the femoral site
Replace the arterial catheter only when clinically indicated
Remove the arterial catheter when no longer necessary

Sternal Wound Infections

The CDC classifies this surgical site infection as superficial or deep. Based on the CDC definition of a deep sternal wound infection (DSWI), this surgical site infection occurs within 30 to 90 days after a surgical procedure. The incision is dehiscent or deliberately opened, an association exists with fever or localized pain and tenderness, or an abscess has formed. The DSWI is an uncommon but serious complication after cardiac surgery that is associated with unfavorable morbidity and increased mortality.

Old age, diabetes, previous stroke and transient ischemic attacks, congestive heart failure (CHF), and bilateral internal mammary artery grafts for the coronary artery bypass graft (CABG) procedure are risk factors for DSWI after cardiac surgery. Mechanical ventilation duration and ICU and hospital lengths of stay were longer in patients diagnosed with DSWI as compared with patients without DSWI. Staphylococcus aureus and gram-positive bacteria were the most common pathogens. The recommended treatment for DSWI is adequate systemic antibiotic therapy, along with either surgical débridement with antibiotic irrigation and primary closure or sternotomy with flap reconstruction.

Prosthetic Valve Endocarditis

The diagnosis of endocarditis requires a high level of clinical suspicion, considering that the clinical presentation is frequently nonspecific with fever, chills, fatigue, or weight loss. The modified Duke criteria are the gold standard for infective endocarditis (IE) diagnosis: two major, one major and three minor, or five minor clinical criteria are required ( Table 32.1 ). Prosthetic valve IE can occur early (less than 1 year after valve replacement) or late (more than 1 year after surgery). The risk of IE was found to be 1% to 4% early after surgery, and 0.5% to 1% per patient year of prosthetic valve later after surgery. The prosthetic valve and CIED-associated IE incidence has increased in recent years. The reported risk was similar for mitral or aortic valve replacement (AVR), regardless of the type of prosthesis; however, it was higher if more than one valve was replaced. Staphylococcus aureus was reported to be the most common pathogen in prosthetic valve IE (34%), followed by the Streptococcus species (23%), the Enterococcus species (19%), and coagulase-negative Staphylococcus (18%).

Table 32.1

Modified Duke Criteria for Diagnosing Infective Endocarditis

Adapted from Thanavaro KL, Nixon JV. Endocarditis 2014: an update. Heart Lung. 2014;43(4):334–337.

Major Criteria	Minor Criteria
1. Two positive blood cultures with typical microorganisms collected at least 12 hours apart (or one positive blood culture for Coxiella burnetii ) 2. Evidence of endocardial involvement (new murmur, echocardiographic evidence of a cardiac mass, abscess, valve dehiscence)	1. Fever >38°C 2. Vascular phenomena (systemic emboli, Janeway lesions) 3. Immunologic phenomena (Osler nodes, Roth spots) 4. Predisposition to infective endocarditis (previous infective endocarditis or intravenous drug abuse) 5. Microbiologic evidence that does not meet major criteria

Despite the low level of evidence regarding the benefit of antibiotic prophylaxis in the prevention of IE, the current recommendation remains that all patients with prosthetic valves receive antibiotic prophylaxis before dental or surgical procedures. Evidence also suggests that antibiotic treatment decreases the risk of stroke after IE. Based on current guidelines of the American College of Cardiology and the American Heart Association (ACC/AHA), surgery is indicated in prosthetic valve–related IE, resulting in hemodynamic instability, heart failure, or valvular complications such as dysfunction or dehiscence, obstruction or regurgitation, and abscess or fistula formation, but it is not indicated in uncomplicated cases.

Systemic Inflammatory Response Syndrome and Sepsis

Systemic inflammatory response syndrome (SIRS) and sepsis are clinical entities that result from an infection with an inflammatory response. Box 32.2 summarizes the diagnostic criteria for sepsis. The number of sepsis cases reported in the United States exceeds 750,000 per year, of which 50% were treated in ICUs. Fifteen million to 19 million new sepsis cases per year are estimated to develop worldwide each year. Most studies have reported that sepsis mortality remained high over time, and septic shock accounted for the highest mortality, approaching 50%.

Box 32.2

Adapted from Dellinger RP, Levy MM, Rhodes A, et al. Surviving Sepsis Campaign Guidelines Committee including the Pediatric Subgroup. Crit Care Med . 2013;41(2):580–637

Diagnostic Criteria for Sepsis

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