Caring for critically ill patients began through recognizing the unique needs of the acutely injured and postoperative patient. In the 1850s during the Crimean War, Florence Nightingale placed the most seriously ill patients in beds near the nursing station. This stressed the importance of a separate geographic location for critically ill and injured patients. Dr Walter E. Dandy, in 1923, at the Johns Hopkins Hospital created a three bed postoperative unit for neurosurgical patients and staffed the unit with specially trained nurses to manage and monitor these patients. The Second World War brought about the creation of specialized shock units to provide resuscitation for the large number of critically injured soldiers. The 1950s experienced the widespread development of shock units and postoperative recovery units. In addition, respiratory units were created due to the large number of polio patients requiring mechanical ventilation. In 1986, the American Board of Medical Specialties approved certification in Critical Care for the four primary boards: anesthesiology, internal medicine, pediatrics, and surgery.
Surgical Critical Care is a core competency of surgical training and relates to the care of patients with acute, life-threatening or potentially life-threatening surgical conditions. Surgical Critical Care brings together the art of critical care management of severely ill patients with the science of surgical procedures targeted at improving their altered physiology. These surgeons are well versed in the pre and postoperative management of patients after undergoing surgical procedures from any surgical discipline and of any age group. While much of the knowledge base is shared with other critical care specialists, fellowship training provides the surgical critical care specialist with specific expertise relating to the interactions between the patients disease process and the pathophysiologic response to infections, inflammation, ischemia, trauma, burns, and operations. Given the rising rate of Hospitalist comanagement of surgical patients, this chapter will cover the most common surgical critical care patient types, and the management of the most common surgical conditions encountered among these patients for the Hospitalist.
SURGICAL CRITICAL CARE ADMIT TYPES
Patients may be admitted to the ICU from the Emergency Department, preoperatively, immediately postoperatively, or postoperatively after initial admission to the postanesthesia care unit or the ward. Preoperative admission may be required for resuscitation in the event of preoperative respiratory failure, shock, or sepsis. ICU admission may also be required for patients who need invasive monitoring for hemodynamic optimization prior to undergoing surgical procedures.
Postoperatively, patients may be admitted to the ICU for respiratory failure, hemodynamic instability, or close monitoring for complications such as bleeding or other physiologic derangements. Patients may also require admission to the ICU due to exacerbation of underlying comorbidities or after procedures with significant blood loss or massive fluid shifts. Some patients need prolonged mechanical ventilation due to the effects of general anesthesia, airway edema, dysfunctional pulmonary mechanics, acute lung injury, traumatic injury to the respiratory tract, cardiovascular disease, or volume overload. Patients with preoperative renal, hepatic, or pulmonary insufficiency may also benefit from elective postoperative ICU admission, as they may be more susceptible to the adverse effects of narcotics and less likely to tolerate hemodynamic fluctuations.
In the United States, injury is the most common cause of death up to the age of 44 years and the fourth most common cause of death overall based on data from the Centers for Disease Control and Prevention. Three million people were hospitalized for injury in 2013 and many of these patients required admission to a critical care unit. While most severely injured trauma patients are managed at Trauma Centers with comprehensive resources, some will receive at least part of their care at hospitals that are not trauma centers. In most trauma systems, severely injured patients are identified in the field and taken to a Level 1 trauma center because there is an approximately 25% improvement in survival at such centers. Once a trauma patient arrives at a trauma center, they undergo a highly standardized resuscitation process using the Advanced Trauma Life Support (ATLS) program.
The modern day care of trauma patients frequently involves critical care admission. Trauma patients may require ICU admission for many reasons such as observation and management for severe and/or multiple trauma, management of acute respiratory failure, resuscitation of hemorrhagic shock, medical management of traumatic brain injury, and pain control. Patients with multiple injuries frequently require ICU care for both management of their injuries and control of pain, agitation, and delirium. Management of specific injuries requires experience and training in trauma care. When a trauma surgeon is not available, a general surgeon can provide needed expertise as the principles of trauma care are part of general surgery training.
The management of pain and agitation is important for all ICU patients but especially injured patients. Consensus guidelines for the management of pain, agitation, and delirium are available and apply to trauma patients with little if any modification (see suggested readings). Because they have high requirements for pain medication with its attendant risks of respiratory depression and altered sensorium, trauma patients requiring moderate to large doses of analgesia and/or sedation are best managed in an ICU setting to optimize outcomes and minimize complications.
Since traumatic brain injury (TBI) accounts for one third of injury deaths, TBI is a frequent indication for ICU admission. In addition, nearly all trauma patients undergoing acute neurosurgical intervention will require ICU admission for postoperative care. In general, TBI patients need admission to the ICU if they require intubation and mechanical ventilation, if they need frequent (more than every 4 hours) neurologic examination and if they have severe TBI requiring modern-day care. The principles of severe TBI management are best outlined in the consensus guidelines developed by the Brain Trauma Foundation. In addition to emphasizing adequate oxygenation and brain perfusion, the guidelines describe the role of many ICU interventions in the care of patients with severe TBI.
As with any critically injured patient assessment of burn patients begins with the ABCs (airway, breathing, and circulation). Airway compromise must be considered in any burn patient. Signs of airway compromise may not be immediately obvious but may progress rapidly. Supportive measures for potential airway injury should be initiated and early intubation should be considered if signs of airway compromise are present. Clinical signs of potential inhalational injury include: face and/or neck burns, singeing of the eyebrows and nasal vibrissae, carbon deposits, and acute inflammatory changes in the oropharynx, carbonaceous sputum, hoarseness, history of impaired mentation, and/ or confinement in a burning environment, explosion with burns to head and torso, and carboxyhemoglobin level greater than 10%. Stridor or circumferential burns to the neck are absolute indications for endotracheal intubation.
Breathing and oxygenation issues arise from several possible injuries after burns. Direct thermal injury results in upper airway edema and obstruction. Inhalation of combustion products and toxic fumes can cause a chemical tracheobronchitis, edema, and predispose patients to develop pneumonia. Carbon monoxide (CO) poisoning should be considered in any burn patient from an enclosed area. Patients’ with CO levels of less than 20% usually do not exhibit symptoms. CO levels of 20% to 30% result in headache and nausea, 30% to 40% confusion, 40% to 60% coma, and more than 60% death. The classically described cherry-red skin is rare. CO displaces the oxyhemoglobin dissociation curve to the left and as a result hemoglobin has an increased affinity for hemoglobin. The half-life for dissociation is approximately 4 hours at room air but decreases to 40 minutes for patients breathing 100% oxygen. High-flow oxygen should be initiated immediately if CO poisoning is suspected. Inhalational injuries often require bronchoscopy if intubation is needed. An adequately sized endotracheal tube should be used to allow subsequent bronchoscopy. If intubation is delayed until respiratory distress begins intubation is often not possible and a surgical airway must be established.
Blood pressure may be difficult to measure in patients with burn injuries and endovascular volume is often difficult to assess. Often patients are hypovolemic and require large volumes of crystalloid to normalize hemodynamic parameters. For patients with more than 10% BSA burns, fluid requirements for initial resuscitation can be estimated using the Parkland formula. The Parkland formula is calculated by multiplying four times the patient’s weight in kilograms times the percent total body surface area involved in second and third degree burns. This volume of fluid should be administered over the first 24 hours after the burn. Half of the total volume should be administered in the first 8 hours after the burn. The remaining half should be administered over the following 16 hours. The goal urinary output is 1 mL/kg/h for adult patients. In the experience of the authors, this formula effectively approximates the fluid needs for patients with burns between 10 and 40% of total body surface area. Patients with burns larger than 40% often need additional fluid to maintain adequate urine output and hourly urine production should be carefully monitored.
In evaluating the degree of injury, the amount of body surface injured must be evaluated. First degree burns are erythematous skin that is moderately painful to touch without blistering. Partial thickness burns, or second degree burns consist of blistered or broken skin that has a red appearance, is very painful and has wet weeping surfaces. Full thickness burns, or third degree burns are often white or pale and leathery in consistency without pain to pinprick evaluation and are dry on the surface. As a rule of thumb, the area of the palm of the hand with the fingers extended represents 1% body surface area for each person. This can be used as a gauge to determine the total burn area. For calculating initial resuscitation fluids, only the surface of second and third degree burns are used for the calculation. Some clinicians find Figure 46-1 useful in estimating total body surface area burned helpful in evaluating these patients. In adults, a reasonable system for calculating the percentage of body surface burned is the “rule of nines”: Each arm equals 9%, the head equals 9%, the anterior and posterior trunk each equal 18%, and each leg equals 18%; the sum of these percentages is 99%. 1% is made up of the perineum.
Estimating extent of burns. (From Demling RH. Burns & other thermal injuries. In Doherty GM, ed. Current Diagnosis & Treatment: Surgery, 14th ed. New York: McGraw-Hill; 2015:227-240.)
Patients should receive adequate supplementary oxygen and endovascular volume replacement. Pain control is extremely important in these patients as well. Second degree burns are extremely sensitive to air-flow so patients should be covered with clean linens or nonadherent dressings to decrease the flow of air across the wounds. Blisters should not be purposefully ruptured and cold packs should not be applied to burned skin. Systemic antibiotics are not indicated. Tetanus status should be evaluated and vaccination given if needed. Criteria for transfer are presented in Table 46-1.
TABLE 46-1Criteria for Transfer of Burn Patients ||Download (.pdf) TABLE 46-1 Criteria for Transfer of Burn Patients
Burn injuries that should be referred to a burn center include:
Partial thickness burns greater than 10% total body surface area (TBSA).
Burns that involve the face, hands, feet, genitalia, perineum, or major joints.
Third degree burns in any age group.
Electrical burns, including lightning injury.
Burn injury in patients with preexisting medical disorders that could complicate management, prolong recovery, or affect mortality.
Any patient with burns and concomitant trauma (such as fractures) in which the burn injury poses the greatest risk of morbidity or mortality. In such cases, if the trauma poses the greater immediate risk, the patient may be initially stabilized in a trauma center before being transferred to a burn unit. Physician judgment will be necessary in such situations and should be in concert with the regional medical control plan and triage protocols.
Burned children in hospitals without qualified personnel or equipment for the care of children.
Burn injury in patients who will require special social, emotional, or rehabilitative intervention.
CLINICAL MANAGEMENT OF SELECTED CONDITIONS IN THE SURGICAL ICU
Rib fractures are a commonly encountered traumatic injury across many medical disciplines. The overall mortality of rib fractures is approximately 10%, with mortality increasing with each additional rib fracture and worsening prognosis among patients older than 55 years old. Patients with limited pulmonary reserve at baseline or due to lung contusion are at higher risk for adverse outcome. Flail chest deformity, commonly defined as three or more consecutive ribs fractured at two or more locations results in impaired pulmonary physiology. This impairment can also be produced when ribs are fractured on each side of the sternum. These fracture patterns result in paradoxical chest wall movement which limits the ability of patients to comfortably breathe. Morbidity is increased in this patient population from short and long term disability and disease related complications, with up to 60% of patients remaining disabled. Common complications include prolonged mechanical ventilation, pneumonia and acute respiratory distress syndrome. Epidural anesthesia has been shown to decrease need for mechanical ventilation and retain baseline pulmonary status. Despite aggressive analgesia and excellent pulmonary hygiene, up to 60% of patients inevitably require prolonged mechanical ventilation. The duration of this ventilation on average is 13 days. Surgical rib fixation has recently grown in popularity due to recent data showing that this procedure may decrease the length of mechanical ventilation. Surgical rib fixation has also been described as a salvage therapy to decrease the duration of mechanical ventilation after failing medical management for flail chest.
Early recognition of postoperative bleeding and initiation of appropriate therapy is imperative as patients can progress quickly to life-threatening hemorrhagic shock. In the immediate postoperative period (<24 hours), the presence of hypotension and tachycardia should constitute a presumptive diagnosis of bleeding until another cause is clearly identified. The patient should be examined immediately for signs of hemorrhage from surgical incisions, drains, tubes, or intravenous lines. If significant (>100-200 mL) or ongoing drainage is noted, the surgical team should be notified immediately. The patient should also be examined for evidence of ecchymosis, soft tissue swelling, and abdominal distension. In the case of trauma patients, missed external (ie, lacerations) or internal (solid organ) injuries may also be present and need to be rapidly identified. A large volume of blood can be sequestered within the chest, abdomen, retroperitoneal, and thigh compartments. Hemorrhage into these areas may be difficult to identify and often require advanced imaging such as x-ray, bedside ultrasound, or CT scan. Imaging studies that can be performed in the ICU should be used preferentially and transporting the patient should be avoided unless they have been appropriately stabilized. If a patient is stable enough to undergo a CT scan, it should be performed with IV contrast as this will demonstrate both old hematoma and the presence of active bleeding.
Postoperative bleeding can be the result of bleeding from the surgical site or surrounding tissues, diffuse coagulopathy, or a combination of these factors. Coagulopathic, or “nonsurgical,” bleeding is often propagated by factors such as hypothermia and acidosis. Hypothermia causes platelet dysfunction via decreased platelet adhesion and aggregation and acidosis decreases thrombin generation, factors which combine to significantly impair the clotting cascade. Bleeding also propagates coagulopathy through the ongoing loss and consumption of clotting of factors as well as dilutional coagulopathy from resuscitation. Hypothermia should be addressed immediately by administering warmed intravenous fluids, applying warmed blankets or forced-air rewarming units, and increasing the ambient room temperature. Acidosis can be addressed with volume resuscitation to improve tissue perfusion, mechanical ventilatory adjustments, and correction of the underlying source (bleeding, infection, etc).
As noted above, postoperative coagulopathy is often multifactorial. The patient’s history should be reviewed for the presence of known congenital bleeding disorders, such as Von Willebrand disease or hemophilia A or B, and these should be addressed as indicated. In the setting of suspected ongoing bleeding, serial laboratory tests (CBC, PT, PT, INR, fibrinogen) should be drawn every 4 to 6 hours. Platelets should be administered in order to maintain a level more than 50,000. Cryoprecipitate should be given in the setting of consumptive coagulopathy to maintain a fibrinogen level more than 100 g/L. An INR of ≤1.5 should be achieved using fresh frozen plasma (FFP), which contains all of the clotting factors, or prothrombin complex concentrate (PCC). PCC contains the vitamin K-dependent coagulation factors (II, VII, IX, and X) and stored as a lyophilized powder following extraction from large donor-pooled plasma. PCC can be used to rapidly reverse warfarin-induced coagulopathy with a significantly lower volume of administration as compared to FFP. In addition, there is some data to suggest it is also effective for hemorrhage or trauma induced coagulopathy.
BLOOD TRANSFUSION—MASSIVE TRANSFUSION
The use of blood transfusion in the ICU is extremely common, with as many as half of all ICU patients receiving at least one transfusion during their stay. In nonbleeding postsurgical patients, the criteria for blood transfusion may vary widely among individual surgeons. Historically, many patients were managed using a liberal transfusion strategy in order to achieve hemoglobin of 10 g/dL. However, recent data suggests that the use of liberal transfusion criteria actually has negative consequences for patients. As a result, hemoglobin of 7 g/dL in nonbleeding patients without evidence of cardiovascular disease is used routinely as a transfusion trigger. (See Chapter 57: Blood Products in the Postoperative Period.)
Massive transfusion is most commonly defined as the administration of 10 or more units of packed red blood cells within a 24-hour period. The need for massive transfusion is most commonly associated with gastrointestinal bleeding and severe traumatic injuries. These patients often receive large volumes of crystalloid in addition to packed red blood cells which can result in a dilutional coagulopathy. In addition, as many as 25% of trauma patients arrive at the hospital already coagulopathic and are at an increased risk of mortality. The presence of coagulopathy needs to be addressed early among patients requiring massive transfusion with the addition of FFP and platelets in a balanced ratio. Over the last 10 years, data from the military experience in Iraq and Afghanistan has suggested improved outcomes with the early use of a 1:1:1 ratio of plasma to red blood cells to platelets in patients at high risk for needing massive transfusion. This ratio was selected in order to more closely mimic the composition of the whole blood lost by the patient. Subsequent analysis in civilian trauma centers has demonstrated a 3- to 4-fold decrease in early mortality with the administration of a 1:1:1 ratio within the first 6 hours although overall mortality was not affected. Thus, the early use of a balanced blood product transfusion ratio should be considered in massively bleeding patients.
In order to effectively administer blood products in emergent situations, many institutions have developed a protocol for massive transfusion in order to streamline rapid delivery. The protocol is activated following clinical evaluation, frequently without waiting for laboratory confirmation, as this can lead to unacceptable delays. As part of the protocol, the blood bank has blood products available that can be delivered rapidly in large quantities and in predefined ratios. The ideal ratio and the quantity of blood products are determined by individual institutions. A typical protocol may consist of an initial container containing 10 units of PRBCS, 10 units of plasma, and two to four packs of platelets. Subsequent containers may contain smaller quantities of these components. Blood products continue to be delivered until the protocol is discontinued by the ICU team, ideally once hemostasis has been achieved. The use of a massive transfusion protocol has demonstrated improved patient survival and reduced rates of organ failure. The development of a massive transfusion protocol requires institutional support and cooperation among multiple services (physicians, nurses, transfusion services, and laboratory) in order to be successful.
DAMAGE CONTROL SURGERY AND THE OPEN ABDOMEN
Critically ill surgical patients and trauma patients often require emergent life-saving surgery. These patients may have extensive injuries that necessitate time-consuming and complex repairs. Historically, a definitive repair of these injuries was attempted during the initial operation despite prolonged operative times. Unfortunately, many of these patients deteriorated intraoperatively or in the acute postoperative period due to the detrimental physiological effects of long operative time combined with extensive comorbidities and traumatic injuries. Therefore, surgical management of these patients shifted from prolonged definitive repair to damage control techniques to avoid further physiological derangement.
In 1993, Rotondo et al are credited with modernizing the techniques of damage control surgery for trauma patients. Damage control surgery is defined as the use of surgical techniques to rapidly control hemorrhage and contamination and defer definitive repair in an effort to temporize the patient and leave the operating room expeditiously to initiate aggressive resuscitation in the intensive care unit postoperatively. Definitive repair is deferred to avoid the lethal triad, which consists of hypothermia, acidosis, and coagulopathy.
Prolonged time in the operating room inevitably leads to progressive hypothermia which leads to dysfunctional coagulation. As the coagulation cascade begins to fail, the patient will lose more blood which leads to further hypothermia and increased acidosis secondary to inadequate perfusion. Acidosis further uncouples the coagulation cascade leading to more hemorrhage. By employing damage control surgery, bleeding and contamination is rapidly controlled to avoid the inevitable death spiral of the lethal triad.
Preoperative identification of patients who would benefit from damage control surgery is paramount to fully mobilize the essential personnel and equipment to prepare for these critically ill patients. Therefore, current recommendations for a trauma patient in which damage control surgery should be considered include patients arriving from the emergency department with a revised trauma score 5 or greater, patients requiring greater than 2 L of crystalloid or 2 units of blood for resuscitation, or have a pH less than 7.2. For nontrauma patients, indications for damage control surgery include uncontrolled hemorrhage for elective general surgery, complications during complex duodenal ulcer operations, generalized peritonitis, and other forms of severe intra-abdominal sepsis.
Intraoperative indications to abort a traditional definitive operative procedure and transition to damage control surgery include patients who require more than 10 units of blood or more than 12 L of resuscitation, continued acidosis of less than 7.2 and hypothermia of less than 34, major inaccessible venous bleeding, refractory oozing from coagulopathy, need to reassess intra-abdominal contents postoperatively, and the concern for likely abdominal compartment syndrome if the abdomen was closed.
Once the decision has been made to proceed with damage control surgery, the intraoperative goals are appropriately narrowed to expeditiously restore hemostasis and leave the operating room as quickly as possible. Therefore, after opening the patient’s abdomen, the first step is to control hemorrhage. This is initially accomplished with packing to tamponade bleeding followed by various rapid maneuvers such as splenectomy, blood vessel isolation, liver packing, etc. Once bleeding has been temporarily controlled, this provides a crucial window for the anesthesia team to “catch up” and try to replace lost intravascular volume and blood products. Following hemorrhage control, the next step in damage control surgery is to stop enteric contamination. Often, this means removing portions of damaged or necrotic bowel, stapling off the ends, and leaving the intestine in discontinuity. Taking additional time to reconnect the remaining intestine would only add unnecessary time to the operation and have a high chance of anastomotic failure.
With bleeding and enteric contamination controlled, the abdominal fascia is left open with the plan of returning to the operating room in 24 to 48 hours for definitive repair once the patient can be adequately resuscitated in the intensive care. In general, most surgeons temporarily cover the visceral contents of the abdomen with a vacuum assisted dressing (Figure 46-2). This aids in keeping abdominal domain and preventing desiccation of the intra-abdominal contents. If the intestine is edematous secondary to the massive resuscitation required in these critically ill patients, several return trips to the operating room are often necessary for abdominal washout and replacement of temporizing dressings. Ideally, the abdomen should be closed within 7 days of the initial surgery because complications of fascial closure rise dramatically after this timeframe. If this is not achieved, the abdomen sometimes has to remain without fascial closure and be allowed to granulate over time. The bowel must not become dry and wound care is extremely important. These patients are at high risk for gastrointestinal atmospheric fistula formation (Figure 46-3).
An open abdomen covered with a vacuum assisted closure device.
An open abdomen due to severe abdominal edema; granulation tissue and fibrous exudate can be seen over this abdomen. Over time the wound will contract and re-epithelize if fistulas do not form.
PREVENTION AND MANAGEMENT OF STRESS GASTRITIS
Patients admitted to critical care units are at risk for developing stress-related mucosal damage (SRMD) leading to stress gastropathy. Approximately 1.5% of critically ill patients develop SRMD as a result of severe physiologic stress. The cause of SRMD is splanchnic hypoperfusion and mesenteric ischemia making SRMD a form of organ-failure. With hypoperfusion, gastric mucosal cells cannot neutralize acid, perpetuating cellular toxicity. Stress gastropathy may occur as a result leading to gastrointestinal bleeding which may be severe leading to hemodynamic instability and, in severe cases, death. Stress gastropathy should therefore be distinguished from peptic ulcer disease where increased acid production is the norm. Most patients with stress gastropathy are actually achlorhydric.
The currently accepted risk factors for SRMD in ICU patients are mechanical ventilation for at least 48 hours and primary coagulopathies. Other variables that have been associated with increased risk include the use of high dose glucocorticoids, severe head trauma, extensive thermal burn injury, organ transplantation and severe liver dysfunction. Although now uncommon, gastrointestinal bleeding secondary to stress gastropathy is associated with a fourfold increase in ICU.
Stress gastritis prophylaxis reduces SRMD and is indicated in ICU patients who are on mechanical ventilation or in those with coagulopathy or one of the other risk factors described above. The most commonly employed prophylaxis is pharmacologic, and both histamine type 2 receptor antagonists and proton pump inhibitors are utilized. Other options for prophylaxis include antacids administered every 4 hours and titrated to an alkaline gastric pH, and sucralfate, an orally administered cytoprotective agent that coats the gastric mucosa providing protection against damage. There are data to suggest that once a patient is tolerating enteral feedings, they likely do not need stress gastritis prophylaxis. It is important to emphasize that stress gastritis prophylaxis is not indicated in patients who are NPO or have an NG tube, unless they are on mechanical ventilation or have one of the other recognized risk factors. As a result, stress gastritis prophylaxis should very rarely be used outside the ICU.
With the rising rate of hospitalist comanagement of surgical patients, many hospitalists will need to be able to manage patients in and out of the surgical ICU. The most commonly encountered types of surgical critical care patients are postoperative, trauma, and burn patients. Effective comanagement requires the hospitalist to know how to recognize and manage common conditions and complications in these patient populations.
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