Postoperative patients who require critical care include: those planned for intensive care unit (ICU) admissions because of an anticipated lengthy operative course and recovery and those requiring ICU care because of unforeseen clinical circumstances or emergencies. Patients who require standard immediate postoperative care are generally admitted to a postanesthesia care unit (PACU). Depending on a hospital's unique capabilities, a PACU is capable for caring for the general ongoing mechanical ventilation and hemodynamic needs of a patient, under the supervision of an anesthesiologist.
Though a PACU can and should be capable of functioning at the same level of an ICU, in reality the day-to-day comprehensive multidisciplinary management is efficiently accomplished in the medium and long-term in a formal ICU with trained intensivists. In the circumstance where a PACU cares for patients who are awaiting an ICU bed, formal consultation with an intensivist for ongoing care is highly valuable.
There are some patient populations, such as those undergoing liver transplant, cardiac and trauma surgery, for whom assured direct postoperative admission to an ICU and avoiding the PACU altogether are essential to ensure optimal care by experienced specialized staff.
A unique aspect of the critical care management of surgical patients is that the information about the patient needed by the intensivist from the preoperative and intraoperative care is often fragmented. In the United States, surgical patients are always followed primarily by the surgeon(s) who performed the operation. Subspecialists who cared for the patient preoperatively and the anesthesiologist who cared for the patient intraoperatively may have important information relevant to the ICU clinicians. For example, the estimated blood loss value may vary widely depending on who reports these data (surgeons often underestimate blood loss). Data about unforeseen difficult airways, intraoperative hypotension, greater than expected blood loss, and other complications are often not readily available or communicated to the ICU, and the intensivist should be aware of this phenomenon and assured that they have the most accurate and comprehensive picture of the patient admitted to the ICU. When feasible, the intensivist should make every effort to begin their consultation intraoperatively. Although not practical in some situations, this certainly helps the ICU ensure continuity of care for patients who are in the extremes of illness. At our institution, the intensivist has been called as a consultant to the operating room to assist in unusual circumstances such as patients with severe hypoxemia, unusual new echo findings, persistent and increasing vasopressor requirements, etc.
Unlike standard medical ICU patients, the surgical ICU patient can have many foreign bodies in the form of tubes, drains, and surgical-related phenomena such as an open abdomen, stoma, flap, altered anatomy, and complicated surgical incision. It is of the utmost importance that the ICU staff understands exactly the type and purpose of each of these as well as how these tubes should be managed. Some tubes are so-called critical and their inadvertent removal can have potentially devastating consequences. Suction tubes come with a variety of suction methods (self-suction, continuous suction, intermittent suction, suction with concomitant irrigation, etc). The quality of drain output (bilious, bloody, serous, purulent, etc), quantity, and changes to such output overtime can give the intensivist vital information. Though a comprehensive description and purpose of every possible surgical device is beyond the scope of this text, we describe some of the more common ones.
Chest tube/drain—Flexible plastic tube inserted through chest wall into pleural space usually to remove air or fluid/blood (Figure 51–1).
Pigtail drain—Drain with a coil at the end, which helps keep it in place and allows for more effective drainage through the small holes in the end; typically placed by interventional radiology though sometimes also used as a closed-chest suction drain (Figure 51–2).
Hemovac—Similar to a JP/Blake but much higher suction power; often used in orthopedics and helpful for removing/draining blood (Figure 51–3).
Sump drain—Also known as “Abramson triple lumen drain.” This is a large drain with 3 ports, typically used with wall side suction and simultaneous irrigation; often used to continuously irrigate a surgical bed postoperatively (Figure 51–4).
Jackson Pratt—Also called a “JP drain”; closed suction that comes in flat and round forms and in various sizes connected to a grenade-shaped bulb via plastic tubing (Figure 51–5).
Blake—Similar to JP drain, more rigid, designed differently; thought to clot less often. Often tunneled with a sharp metal applicator that is then removed (Figure 51–6).
Penrose—Yellow-colored soft rubber/floppy tube that is often used to keep a surgical site open for continuous drainage after infection/abscess (Figure 51–7).
Loop ostomy rod—This is a temporary device left under a loop ileostomy or colostomy to prevent retraction into the peritoneum; usually removed by postoperative day 5.
T-tube—A drain shaped like a T placed into the biliary system, usually the common bile duct.
GJ tube/Moss tube—This tube has 2 ports (1 to stomach and 1 to jejunum); often used for feeding in patients not tolerating gastric feeds.
Jackson Pratt (JP) drain.
A detailed discussion of fluid management and fluid responsiveness is a complicated and controversial topic beyond the scope of this chapter. Some key elements are universal to the surgical patient, however. Information about intraoperative fluid and blood loss coupled with fluid/blood-product administration can give the intensivist a clue about the resuscitation status of a newly admitted patient. Physical examination, though always important, is not the most accurate means of assessing volume status in this patient population. Fluid responsiveness can be assessed with a variety of more invasive and noninvasive means such as goal-directed cardiac ultrasound (feasibility and potential clinical utility of goal-directed transthoracic echocardiography performed by noncardiologist intensivists using a small hand-carried device in critically ill patients1) and pulse contour analysis. Focused transthoracic cardiac ultrasound is a method that is noninvasive and is gaining popularity in the assessment of fluid status.2
Central venous pressure measurement has been proven to not correlate with fluid status when spot-checked or when trended over time.3 The use of a Swan–Ganz catheter (often called a pulmonary artery catheter) is used routinely during cardiac surgery and liver transplantation to measure cardiac index and calculate systemic vascular resistance, but its value has not been shown in other patient populations.
Rapid administration of small boluses of isotonic fluid with real-time monitoring of a patient's clinical response is a time-proven method in the initial resuscitation of postoperative ICU patients. Isotonic fluids should generally be the fluid of choice. pH neutral fluids should be used primarily as massive quantities of sodium chloride will cause an iatrogenic hyperchloremic metabolic acidosis. The intensivist should keep in mind that a patient's output may be substantially higher than urine output given drain output, etc.
Albumin is commonly used as a resuscitative fluid; however, its use is controversial. Most intensivists would agree that its utility makes most sense in patients with hypoalbuminemia secondary to cirrhosis. Synthetic starches are no longer used clinically as they can contribute to renal injury and may contribute to increased mortality.
The aggregate of evidence from the last 15 years generally supports the notion that limited transfusion thresholds are correlated with superior outcomes in most patient populations. These include postoperative patients and patients with resuscitation for septic shock. A recently published study in the New England Journal of Medicine randomized 461 patients to a restrictive versus a liberal (hemoglobin threshold of 7 vs 9, respectively) transfusion strategy in patients with acute upper gastrointestinal bleeding. The rate of recurrent bleeding was lower and the survival was higher in the restrictive group.
Patients with active acute coronary syndromes have been shown to do poorly when severely anemic. Likewise, restrictive strategies for transfusion have not been shown to be superior in patients after heart surgery.4
Although restrictive transfusion strategies are certainly applicable to most patients in the ICU with anemia or minimal bleeding, it should be noted that aggressive use of packed red blood cells, fresh frozen plasma, and platelets along with minimal to no crystalloid should be the strategy during acute and exsanguinating hemorrhage, particularly in trauma patients. In these circumstances, crystalloid use should be minimized as it contributes to hypothermia, dilution of coagulation factors, and promotes acidosis. Trauma surgeons often say “you don't bleed crystalloid; you bleed blood.”
Although historically the surgeon dictated the timing of initiation for feeds based on such things as physical examination, flatus, nasogastric tube output, and bowel movements, such clinical practice is not evidence driven. Although the consequences of this practice may not be substantial in the usual surgical floor, such means of determining when to feed a critically ill patient may lead to deleterious outcomes. The urgency of initiating feeding in large part depends on the preoperative nutritional status of the patient. Patients who have been in the hospital for several days or weeks with inadequate nutritional support who subsequently require ICU care are in more urgent need for expeditious nutritional support. Undernutrition is prevalent in all ICUs and often in surgical ICUs. Having a nutrition protocol helps narrowing the gap between what the patient is getting and what the caloric goal is, though this is less important in the first week of critical illness. Initial low-volume (ie, trophic) enteral nutrition resulted in clinical outcomes similar to those of early full-energy enteral nutrition but with fewer episodes of gastrointestinal intolerance.5 However, restriction of nonprotein calories (permissive underfeeding) was not associated with lower mortality than that associated with planned delivery of a full amount of nonprotein calories.6
A few practices that should be standard are worth mentioning. Intermittent interruption of enteral feeding during an ICU course can contribute to malnutrition in the patient who is in the ICU for over several days. Practices such as NPO before planned procedures, delayed and cancelled operative times, computed tomography (CT) scan, and interruption for various other reasons become cumulative and can substantially contribute to patients receiving suboptimal feeds. It is our practice to minimize this phenomenon by minimizing reasons why patients' feeds are interrupted. For example, patients with endotracheal tubes or a cuffed tracheostomy have protected airways, and several planned procedures or operations can safely be accomplished with enteric feeds continued until the timed event. It is customary to establish an NPO status only if the procedure will entail surgery in the abdomen or airway, or the patient must be positioned in the prone position. Thus patients scheduled for orthopedic, brain, plastic, and extra-abdominal general surgery procedure can be spared unnecessary interruption of feeds. Given the nutritional needs are complex in this population, a dedicated nutrition team trained in critical care nutrition is an essential element to the care of the surgical ICU patient. Early enteral nutrition has been shown to improve infectious complications and mortality when compared to late enteral nutrition including in pancreatitis patients. Early parenteral nutrition (< 7 days post-ICU admission) has been associated with increased risk of nosocomial infections without benefit.7
Principles of ventilation in a surgical ICU are no different from those in any other ICU. There are, however, different practices based on the expertise and biases of individual ICUs. Cardiac surgery ICUs tend to use pressure control ventilation, whereas trauma ICUs tend to more heavily rely on airway pressure release ventilation. Most standard surgical ICUs use either volume control (guaranteed volume) modes or dynamic hybrid modes such as volume-targeted pressure control mode (eg, pressure-regulated volume control [PRVC]).
Regardless of the mode or ventilator used, the surgical intensivist must be aware of the forces that influence mechanical ventilation in patients who undergo abdominal surgery. This is especially true in trauma and emergency surgery where there is often edema of the internal organs, and the associated increased abdominal pressure pushes upward on the diaphragm, effectively reducing functional residual capacity. This contributes to atelectasis and ventilation/perfusion (V/Q) mismatch.8,9 When abdominal pressure begins to impair function in the pulmonary, renal, cardiovascular, or gastrointestinal systems, abdominal compartment syndrome should be recognized early and addressed.
Liberation From Ventilator
Successful liberation from mechanical ventilation relies on the application of clinical judgment and medical and nursing intervention. Predictors of successful extubation have significant limitations; some remain complicated and cumbersome to be used at bedside. Paired sedation interruption with daily spontaneous breathing trial10 (SAT + SBT) has been shown to improve outcome, including more ventilator-free days and less ICU and hospital length of stay (LOS), and 1-year mortality.
Utilizing paired SAT + SBT (spontaneous breathing trial + spontaneous awakening trial) as part of the ABCDEF bundle is an essential part of successful liberation from mechanical ventilation. Tools are available on this website published by the society of critical care medicine: http://www.iculiberation.org/news/Pages/Webcast-Explores-Implementing-New-ABCDEF-Bundle-in-Your-ICU.aspx.
Extubation attempts may fail in up to 23.5% of patients and lead to an increased hospital mortality of 30% to 40%. The use of postextubation noninvasive ventilation (NIV) outside of exacerbation of chronic obstructive pulmonary disease (COPD) should be cautioned as it leads to unnecessary delay in reintubation and worsened outcome particularly in surgical patients.11,12 High-flow nasal cannula (HFNC) oxygen has been used in hypoxemic respiratory failure and shown to improve 90-day mortality when compared with NIV.13 The routine application of HFNC to patients in the setting of extubation failure due to hypoxemia is feasible but has not been studied to date.
The Society of Critical Care Medicine published updated clinical practice guidelines for adult ICU patients in 2013, which are applicable to the surgical ICU. Although there is variability among ICUs in terms of practice norms, an emphasis on minimizing pain and agitation while also preventing delirium should be the primary goal. The impact of delirium in the ICU on hospital LOS, long-term cognitive impairment, and mortality cannot be overemphasized.14,15 The Vanderbilt University Medical Center Delirium and Cognitive Impairment Group have created www.icudelirium.org that provides medical professionals with a variety of pearls and tools we use in our practice. For example, ABCDEF is the bundle of measures which includes Assess for and manage pain, Both Spontaneous awake and breathing trials, attention to Choice of sedation and analgesia, Delirium monitoring and management, Early mobility, and Family engagement.
Though any patient who is newly intubated requires analgesia, unique to surgical patients is incisional pain. Analgesia should therefore be the primary and initial focus for patient care. Multimodal therapy including narcotic drip/bolus titration, enteral/IV acetaminophen, and neuroleptics could be utilized. Nonsteroidal agents have a role in the patient without precarious renal function and with low risk of bleeding. Dexmedetomidine, though not a primary analgesia agent, is narcotic sparing and has pain-relieving properties. Low-dose ketamine drips for patients with refractory pain or a significant history of narcotic use previous to admission can attenuate subjective pain scores.
Validated sedation scales such as The Richmond Agitation-Sedation Scale (RASS) or The Riker Sedation-Agitation Scale (SAS) are paramount to goal-directed delivery of sedatives by the nursing staff. We use the RASS that takes less than 20 seconds to perform, and has been shown to be highly reliable and effective. Noncontinuous sedation protocols have been shown to decrease ICU LOS when compared with continuous sedation with daily interruptions.16
Abdominal Compartment Syndrome
The surgical intensivist should always keep in mind the phenomenon of abdominal compartment syndrome. The World Abdominal Compartment Society (www.wsacs.org) provides consensus guidelines on this pathology that should be reviewed.
Many postlaparotomy patients have some element of abdominal hypertension. A normal intra-abdominal pressure in most critically ill adults is between 5 and 7 mm Hg. When this pressure is associated with new organ dysfunction and limits perfusion to vital organs (typically when 20 mm Hg with or without an abdominal perfusion pressure < 60 mm Hg), treatment needs to be initiated emergently. Although sedation/analgesia, body positioning, gastric/colonic decompression, and fluid resuscitation/diuresis may be attempted initially, rapid correction with either percutaneous drainage or laparotomy (ie, relaparotomy with abdominal fascia left open) should be performed.
The intensivist should have a low threshold of measuring abdominal pressures with either a standard commercial device, or a Foley catheter with 50 mL injected into bladder connected to standard pressure transducer in the supine and flat patient. It is important to have a baseline pressure and frequent serial abdominal examinations. The intensivist should be aware that abdominal compartment could still develop in a patient with an incompletely open abdomen if the fascia is still under tension or the lapartomy was limited in length. Although these patients often respond seemingly well with initial, intermittent fluid boluses, their underlying pathology worsens over time.
Mechanical and chemical deep vein thrombosis (DVT) prophylaxis is mandatory for the vast majority of patients in the surgical ICU. Although some surgeons are reluctant to begin chemoprophylaxis in the immediate postoperative period, general guidelines should be implemented at each institution to ensure its use. At our hospital, patients with traumatic brain injury are routinely started on chemoprophylaxis 48 to 72 hours after admission if there is no evidence of continued bleeding on CT scan.
Inferior vena cava filters are generally reserved for those patients with a long-term contraindication to chemoprophylaxis, patients with acute DVT and a contraindication to systemic anticoagulation, and patients diagnosed with a new DVT or pulmonary embolism while already on systemic anticoagulation.
The absolute indications for stress ulcer prophylaxis include severe sepsis or septic shock, mechanical ventilation more than 48 hours, major burn injury, and patients with coagulopathy. In practice, stress ulcer prophylaxis is also used for most ICU patients, as well as elderly patients on NSAIDs and those on high-dose steroids (> 250 mg hydrocortisone/d). These recommendations for trauma ICU patients, which are applicable to most postoperative patients, are readily available at www.east.org.
Effective prophylaxis includes proton pump–inhibiting agents (PPI) and H2-blocking agents. Although patients who are tolerating feeds are typically at less risk for developing stress ulcers, the indications for its use are not related to the NPO status of the patient. Thus patients who do not meet the aforementioned criteria who are NPO do not need prophylaxis, and patients who do meet criteria who are tolerating enteral feeds still need chemoprophylaxis. PPI use has been linked to increased C diff rates as well as increased ventilator associated pneumonia.17,18
Antibiotic stewardship is of the utmost importance in the surgical ICU. Antibiotic use is divided into its use in surgery for incisional infection prophylaxis and actual treatment. Guidelines mandate less than 24 hours use when used for prophylaxis; whether that dictates one dose intraoperatively only versus continued dosing for less than 24 hours is individual preference. The exception is in cardiac surgery patients following sternotomy and following transplant surgery in whom 48 hours is preferred—though with limited evidence. Notoriously, ENT/OMFS/Ophthalmology/Plastic surgeons often request prophylaxis for extended durations—it should be emphasized this practice is not ideal and institutional guidelines should be established to limit confrontation in these circumstances.