Cardiac Patients Requiring Emergent Noncardiac Surgery

Preoperative Concerns

The AHA/ACC guidelines recommending proceeding with surgery also recommend assessing clinical risk factors, collecting information about preexisting cardiac illness, and incorporating them to help determine the surgical strategy and to optimize perioperative monitoring and management. In reality, most of the time, the cardiac status of these emergent patients is unknown or possibly manifested intraoperatively with unstable hemodynamics (which may be an indicator of an underlying cardiac condition). In such instances, evaluation and management must go hand in hand, preferably in the hands of an anesthesia provider capable of performing and interpreting point-of-care procedures such as bedside echocardiography or pulmonary artery catheter (PAC) data.

A prudent approach includes aggressive perioperative medical management of the unstable cardiac condition with a goal to shift cardiac interventional therapies, if deemed required, to the immediate postoperative period. In such instances, the conflicting risks and benefits of emergent surgery versus the unstable cardiac condition could put immense pressure on the entire perioperative team with implications on outcomes. A multidisciplinary approach is best if implemented at the time of initial evaluation and must involve all persons available, including the patient, family, surgical team, cardiology and primary care team, if possible.

In most emergency situations, it is often possible to obtain available clinical information and perform a rapid history and physical examination. Additionally, available laboratory and diagnostic data should be reviewed. Routine blood work, if already not sent, should be drawn at the time of intravenous (IV) catheter placement. Coagulation studies and blood type and crossmatch should be included. If required, anticoagulation reversal should be initiated ( Table 16.1 ).

Monitoring needs will depend on the patient's cardiac disease and clinical state. Invasive monitoring, if required, may include an arterial catheter or central catheter. Placement of an introducer sheath allows for both volume resuscitation as well as potential PAC placement if indicated. If clinically indicated, invasive monitoring may be placed preoperatively and is usually well tolerated by most conscious patients under adequate local anesthesia and ultrasound guidance. Handheld ultrasound or bedside echocardiography permits easy and prompt recognition of significant cardiac lesions, and such information provides the operating team an opportunity to incorporate measures to optimize perioperative outcomes. It has been shown that use of such devices can recognize major cardiac abnormalities, especially the presence of unrecognized left ventricular (LV) systolic dysfunction or valvular heart disease.

A significant number of patients presenting for emergency abdominal surgery present with systemic inflammatory response syndrome, sepsis, or septic shock. Early antibiotic administration and goal-directed resuscitation must be initiated when indicated. Significant intracellular and interstitial fluid depletion may exist despite the appearance of normal cardiovascular measurements (blood pressure, CO, stroke volume). Patients typically require administration of resuscitation fluids to maintain blood pressure and circulating volume during emergency abdominal surgery, but must be performed judiciously in a cardiac patient to prevent pulmonary edema or acute ventricular dysfunction. Also, electrolyte and acid–base abnormalities should be corrected. Occasionally, after relieving obstruction (in cases of urosepsis, obstructive jaundice, or intestinal obstruction), there is a potential for patients to become overtly septic or prone to arrhythmia.

Antiaspiration prophylaxis in the form of nonparticulate antacid and, if time permits, an H ₂ blocker or proton pump inhibitor, must be administered to reduce risk of aspiration. Metoclopramide, because of its prokinetic properties, is best avoided in emergency abdominal surgery.

Intraoperative Concerns

Overall, there is no specific anesthetic technique recommended. General anesthesia (GA) is typically indicated because of the emergent nature of the case, with an open abdomen and likelihood of hemodynamic instability with attendant need for ongoing resuscitation. Anticipation of increased sensitivity to anesthetic agents and hemodynamic perturbations is essential. Decreased doses and gently titrated anesthetic agents with close monitoring of the hemodynamics are required.

After initiating emergency fluid resuscitation as needed and placement of appropriate monitors, a modified rapid-sequence induction often balances the risk-to-benefit equation of competing goals of preventing aspiration versus cardiovascular stability. Agents that minimally depress the cardiovascular system (judicious propofol, etomidate, or ketamine for induction and high-dose rocuronium for intubation) are recommended to achieve this goal.

Patients undergoing emergency abdominal surgeries are prone to volume shifts, and use of the arterial tracing for evaluation of systolic pressure or pulse pressure variation is predictive of fluid responsiveness. A goal-directed fluid therapy approach may assist in appropriate fluid resuscitation. A respiratory-related change of more than 13% suggests that the patient would be fluid responsive. A change of 9% to 13% has been shown to reflect an intermediate range of predictability, a gray zone, in which the patient may be fluid responsive. If the systolic pressure or pulse pressure variation is less than 9%, it is unlikely that the patient would be fluid responsive.

In patients with coronary artery disease (CAD), it is important to avoid excessive myocardial oxygen demand (MVO ₂ ), which could elicit or exacerbate myocardial ischemia. Elevated heart rate (HR) can be controlled with a short-acting β-blocker, such as esmolol, especially to blunt the sympathetic response during laryngoscopy, surgical stimulation, and emergence from GA. Nitroglycerin can also be useful to treat hypertension, especially if the HR is low and hypertension persists. Nitroglycerin can provide both venodilation and dilation of coronary arteries. In addition to demand-related ischemia, adequate supply of oxygen to the myocardium must be maintained in the form of correction of anemia, hypovolemia, and prevention of desaturation. Vasopressor or inotropic infusion might be necessary with the anesthetic agents to maintain an adequate perfusion pressure or if cardiomyopathy is severe. A central venous catheter (CVC) can be placed to provide central access for the administration of a vasopressor or inotrope. Patients with cardiomyopathies may not tolerate rapid fluid shifts during emergency abdominal surgeries and therefore may need monitoring of mixed venous oxygen saturation or CO to direct vasoactive agent therapy. Because of third spacing, frequent monitoring and replacement of electrolytes is necessary. Severe hyperglycemia should be controlled with IV insulin, and hypothermia must be prevented.

Patients with coexisting valvular heart disease need special consideration, particularly patients with aortic stenosis who require maintenance of cardiac preload, systemic vascular resistance (SVR), and myocardial contractility. Rapid correction of arrhythmias is necessary because patients with aortic stenosis and associated LV hypertrophy are likely to poorly tolerate such arrhythmias. Although the usage of PACs is declining, the presence of severe pulmonary hypertension (PH) or severe LV or right ventricular (RV) dysfunction may be an indication for monitoring with a PAC to guide the administration of nitric oxide or other pulmonary vasodilators.

Transesophageal echocardiography (TEE) is used for real-time evaluation of cardiac function and restrictive fluid management during surgery. Perioperative hemodynamic management with TEE may be useful for gastrointestinal tract surgeries in patients with severe cardiac disease. See Chapter 10 for an approach to using TEE for fluid resuscitation.

Despite maximal medical management, if a patient continues to be unstable during emergency abdominal surgery, mechanical support for the ventricle (e.g., intraaortic balloon pump [IABP] or percutaneous ventricular assist device [VAD]) or venoarterial extracorporeal membrane oxygenator (ECMO) can be initiated intraoperatively to facilitate successful completion of surgery and hemodynamic stabilization. This requires resources, early planning, and communication with various teams. Additionally, there is the added time constraint, especially after a sudden collapse, to establish mechanical support or initiation of extracorporeal circulation before hypoxic cerebral injury occurs.

Postoperative Period

An elevated level of postoperative care is necessary in cardiac patients who have undergone emergency abdominal surgery, and intensive care unit (ICU) admission should be considered for these patients for prompt recognition and management of complications. In the immediate postoperative period, there is usually relative hypovolemia from third spacing with associated increased myocardial work. During this phase, resuscitation fluids should be administered cautiously guided by invasive hemodynamic monitoring and circulatory support in the form of vasopressor/inotrope, to prevent precipitation of heart failure. Over the ensuing postoperative days, a state of equilibrium develops when active sequestration stops, followed by a phase of diuresis during which the patient mobilizes fluid and recovers. These fluid shifts are associated with intracellular movement of ions. Hypophosphatemia, hypomagnesemia, and, in particular, hypokalemia are usually evident, requiring regular serum chemistry monitoring. During the equilibrium phase, administration of IV fluid is balanced on whether the current aim is to augment intravascular volume to ensure adequate organ perfusion or to prevent further tissue edema. During the diuretic phase, the main goals are to allow the patient to return to baseline body weight and to aggressively replete electrolytes. Due to the risk of postoperative sepsis, respiratory, and cardiac events being the most common causes of death after discharge from the ICU, patients should be continued to be watched carefully on the floor.

Recognition of Preexisting Cardiac Disease in Trauma Patients

Trauma victims frequently arrive to the receiving hospital emergency department (ED) unconscious, intubated, or unable to provide a history. History from emergency medical workers or family may reveal the details of the trauma patient's cardiac history. However, this often may not be readily available. For a trauma patient brought emergently to the OR when a brief history is unattainable, various signs may indicate the presence of prior or current cardiac disease.

A cursory physical examination revealing a midline sternotomy scar is likely associated with prior cardiac surgery. In an older patient, evidence of a prior sternotomy should alert the physician to either prior coronary bypass grafting surgery and history of CAD or potentially prior valve surgery. Clinicians should consider the presence of congenital correction in a younger trauma patient with a sternotomy scar. Other evidence of cardiac disease includes the presence of an implanted cardiac electronic device (i.e., implanted pacemaker or defibrillator) or the battery pack and driveline of a VAD.

Additionally, rapidly identified physical examination clues of current cardiac disease may include clubbing of digits indicating uncorrected cyanotic heart disease, a heave on chest palpation indicating an enlarged cardiac chamber, an audible or palpable thrill demonstrative of severe valvular abnormality, or the auscultation of the click associated with mechanical prosthetic valves. The electrocardiogram (ECG) may reveal pacer spikes in a pacer-dependent patient.

Consideration should also be given to the potential concomitant use of outpatient anticoagulation and antiplatelet medications in trauma patients with possible prosthetic heart valves, CAD, or other implanted devices (e.g., VADs). Plans should be made for immediate coagulation testing and possible massive blood product administration in this context.

Finally, in older trauma patients without obvious signs or symptoms of cardiac disease, the clinician should presume that at least mild diastolic dysfunction exists, and consideration should be made for rational fluid management and resuscitation with appropriate monitoring.

Preparation for Trauma Patients With Cardiac Disease

Trauma patients with cardiac disease require careful planning and preparation. This planning should include a review, time permitting, of the patient's prior medical and surgical history, a review of the current trauma presentation (including mechanism, issues with transport, field or ED resuscitative efforts), preoperative imaging, and any recent studies (cardiac catheterization, echocardiography, device interrogation). When time is limited and patients present directly to the OR, as much history as possible should be obtained before induction, as well as a limited physical examination focusing on signs of heart failure, previous cardiac surgery, and the presence of existing implanted devices (pacemakers, defibrillators, VADs, medication pumps).

During this preparatory period, consideration should be given to induction agents, circulatory access, and monitoring needs ( Table 16.2 ).

Vasoactive Drugs for Emergent Trauma Preparation

In addition to the preparation of appropriate induction drugs and anesthetic maintenance agents, clinicians should also prepare basic cardiac vasoactive drugs for the purposes of optimizing intraoperative hemodynamics. In a time-limited emergency scenario, preparation of three basic vasoactive drugs (nitroglycerin, epinephrine, norepinephrine) enables the rapid management of most hemodynamic issues for the majority of cardiac patients. Nitroglycerin (starting dosage of 0.5–1.0 µg/kg per minute) provides varying degrees of venous, coronary, and arterial dilation; epinephrine (starting dose of 0.01–0.05 µg/kg per minute) provides arterial vasoconstriction and inotropic support, and norepinephrine (starting dose of 0.01–0.05 µg/kg per minute) provides primarily arterial vasoconstriction with a small degree of inotropic support.

Trauma Care in Older Patients With Established Cardiac Disease

Trauma Care in Adults With Congenital Heart Disease

There are a wide variety of corrected CHD defects that may exist into adulthood and therefore may potentially present in trauma patients, including defects ranging from simple atrial and ventricular septal defects to complex repairs of single ventricles or truncus arteriosus. As of 2017, there were approximately 1.4 million adults with corrected CHD. CHD that is considered complex and of higher risk includes prior Fontan procedures, severe pulmonary arterial hypertension, cyanotic CHD, complex CHD with malignant arrhythmias, and any pregnant patient with CHD ( Table 16.5 ). Although there are recommendations that adults with CHD be cared for in specialized centers, there is always the potential that a trauma victim may be brought to any given hospital at any given time.

Introduction

Neurosurgical emergencies that require immediate surgery and care by an anesthesiologist are mostly caused by head or spinal cord trauma, rupture of cerebral aneurysms or arteriovenous malformations, hematomas, acute hydrocephalus, and intracranial tumors with possible brain herniation. Intracranial hematomas may arise epidurally, subdurally, or intracerebrally and can expand rapidly or slowly. Emergencies affecting the spinal cord include tumors or hematomas causing compression of the spinal cord, which can cause acute spinal cord injuries (SCI).

Patients with severe traumatic brain injury (TBI) or SCI also tend to have other injuries. In addition, if these patients also have significant cardiac disease, management is complex and requires a multidisciplinary approach. Surgery and anesthesia can also subject the injured brain to other secondary injuries as a result of hypotension or hypertension, hypoxemia, hypocarbia or hypercarbia, hypoglycemia or hyperglycemia, fever, or increased intracranial pressure (ICP) that can cause further adverse outcomes.

Preoperative Evaluation

Preanesthesia evaluation should be as complete as possible but is frequently limited by the emergency of the clinical situation. The preanesthetic considerations for patients with cardiac disease involve assessing cardiac and overall health risk, identifying factors that may cause significant perioperative issues, working with cardiology to help optimize cardiac issues if time permits, assessing the risk for a perioperative cardiac event, and developing an anesthetic plan to avoid cardiovascular complications. Patients with coexisting cardiac disease who require urgent or emergent surgical procedures are at increased risk for cardiovascular complications, regardless of the severity of the disease and baseline risk ( Box 16.1 ).

Box 16.1

Modified from Cottrell JE, Young, WL. Cottrell and Young's Neuroanesthesia. 5th ed. Philadelphia: Elsevier; 2010.

Preanesthesia Assessment of Head-Injured Patients

• Airway (cervical spine)

• Breathing: ventilation and oxygenation

• Circulatory status

• Associated injuries

• Neurologic status (Glasgow Coma Scale)

• Preexisting chronic illness

• Circumstances of the injury

  • Time of injury

  • Duration of unconsciousness

  • Associated alcohol or drug use

The preanesthetic assessment includes:

• Airway assessment and management plan ( Fig. 16.1 )

  

• Severity and chronicity of the cardiac lesion

• Effects of the surgical procedure and anesthetic technique on the preexisting condition and cardiac function

• Plan regarding the use of invasive monitoring and risks and benefits of planned invasive monitors

• Plan regarding the selection and use of vasoactive agents

• Use of surface echocardiography for quick assessment of cardiac status and use of TEE based on hemodynamics

When these patients are brought to the OR emergently, there is usually minimal time for a complete preoperative assessment. In these situations, obtaining any significant cardiac history can be extremely difficult, either because of a lack of reliable source of history or the patient being unable to communicate because of mental status changes. The anesthesiologist may have to depend on physical signs and symptoms to look for signs of heart disease or dysfunction. The presence of chest scars may indicate possible prior heart surgery. Physical examination of the chest and listening to the heart sounds may also provide valuable clues to the presence of heart disease. Signs and symptoms of CHF should be carefully assessed. They include rales, wheezing, hepatomegaly, jugular venous distention, ascites, and edema. Physical deconditioning may also be present in patients with significant preexisting cardiac disease. Close monitoring of vital signs as the patient is brought in to the operating suite is vitally important.

Patients who have had a recent myocardial infarction (MI) within the past 4 weeks and require emergent surgery are at extremely high risk for a perioperative cardiac event. For emergent surgery, the goals should be to prevent, detect, and treat ischemia. Consultation should be obtained from a cardiologist if needed and feasible for risk stratification and further management.

Patients with recent cardiac percutaneous coronary intervention (PCI) are also at increased risk if noncardiac surgery is performed within 6 weeks of stenting. This is closely associated with the cessation of antiplatelet therapy in the setting of a surgery-induced prothrombotic state. In patients requiring emergent surgery, the risk of surgical bleeding by continuing antiplatelet drugs has to be balanced against the risk of adverse cardiac events. This can be particularly problematic in patients requiring emergent neurologic surgery because bleeding into the brain can be devastating. Patients in this scenario usually require platelet transfusions in the perioperative period.

Rapid neurologic assessment is performed using the Glasgow Coma Scale (GCS) to stratify the severity of the TBI. A key priority in the management of patients with neurosurgical emergencies is a rapid and accurate diagnosis with computed tomography (CT) to evaluate an expanding lesion that requires immediate surgical intervention. Lesions such as epidural hematomas, subdural hematomas, intracerebral hematomas, and contusions should be evacuated as soon as possible.

Goals in the Anesthetic Management of Neurologic Emergencies in Patients With Head Injury

The primary goal in neurologic emergencies is the prevention of secondary neurologic injury. In the past few decades, the understanding of the causes and the early treatment of secondary brain injury have led to a decrease in the mortality rate of patients with acute neurologic injury. The outcomes of acute neurologic injury are determined by the presence or absence of secondary brain injury. The main contributors to secondary injuries include hypoxia, hypotension, hypercapnia, intracranial hypertension, and brainstem herniation. These factors can also significantly impact the cardiac status of patients with significant cardiac disease ( Table 16.6 ). The duration of systemic hypotension, hypoxia, and pyrexia have all been found to be strongly associated with death. High-dose steroids do not reduce ICP in head trauma and have not been shown to affect outcome. They are not routinely used in the management of these patients. Steroids may be useful in reducing edema in patients with a brain tumor, however.

Some of the key points to be considered while managing these patients include ( Box 16.2 ):

• Maintain cerebral perfusion pressure and treat increased ICP.

• Avoid secondary injuries such as hypotension, hypoxia, hypercarbia and hypocarbia, hypoglycemia and hyperglycemia, and coagulation abnormalities.

• Provide adequate anesthesia and analgesia.

Box 16.2

Modified from Cottrell JE, Young, WL. Cottrell and Young's Neuroanesthesia. 5th ed. Philadelphia: Elsevier; 2010.

Major Goals in the Acute Care of the Brain-Injured Patient

• A.

  Prevention of hypoxemia: maintain Pa o ₂ >60 mm Hg or Sa o ₂ >90%:

  • 1.

    Increase inspired oxygen tension.

  • 2.

    Treat pulmonary pathologic condition.

  • 3.

    Consider positive end-expiratory pressure (≤10 cm H ₂ O).

• B.

  Maintenance of blood pressure:

  • 1.

    Prevent hypotension—maintain systolic blood pressure >90 mm Hg:

    • a.

      Avoid glucose-containing solutions.

    • b.

      Maintain intravascular volume status; aim for euvolemia.

  • 2.

    Treat hypertension:

    • a.

      Sympathetic nervous system overactivity

    • b.

      Increased intracranial pressure

    • c.

      Light anesthesia

• C.

  Reduction in intracranial pressure:

  • 1.

    Head position

  • 2.

    Brief periods of hyperventilation

  • 3.

    Hyperosmolar therapy

  • 4.

    Sedation

  • 5.

    Hypothermia

  • 6.

    Surgical procedures: drainage of cerebrospinal fluid and evacuation of hematoma

Goals in Anesthetic Management of Patients With Spinal Cord Emergencies

Similar to patients with head injury, one of the primary goals in the management of SCI is the prevention of secondary cord injury. A key way to do this is to immobilize the spine, and subsequent treatment has involved anatomic realignment and stabilization with or without surgery.

Secondary neurologic injury is further prevented by maintaining spinal cord perfusion and correcting hypoxia. Autoregulation can be impaired for several hours after injury. Hence, vasopressors, mainly norepinephrine, should be used to maintain mean arterial pressures (MAPs) of at least 65 mm Hg to improve spinal cord perfusion pressure. This may also be required in patients with CAD to maintain cardiac perfusion. Hypertension is also not helpful because it can cause hemorrhage and increase spinal cord edema.

Hyperglycemia should also be avoided after SCI. Blood glucose levels above 177 mg/dL have been associated with worsening neurologic outcomes. Glucose-containing solutions should be avoided in the first 24 hours, and hyperglycemia should be carefully treated.

Large doses of steroids, especially methylprednisolone, have been reported to improve outcomes in patients with spinal injuries in some studies but not confirmed in others. Currently, the administration of steroids remains an institutional or physician preference.

Anesthetic Management of Patients With Cerebral Aneurysm Surgery

Cerebral aneurysm surgery may be emergent in situations when patients present with a subarachnoid hemorrhage. Preoperative evaluation includes assessment of the patient's neurologic condition and grading of the subarachnoid hemorrhage, assessment of the intracranial pathology with review of CT scans and angiograms, monitoring of ICPs, and evaluation of other systemic issues, including cardiac issues.

Careful management of blood pressure during anesthesia induction is particularly important in these patients. Aneurysm rupture or rebleeding during induction of anesthesia may be precipitated by sudden increases in blood pressure during intubation and is associated with a high mortality rate. The risk of ischemia from a reduction in cerebral perfusion pressure has to be balanced with the benefit of reduced chance of aneurysmal rupture, taking into consideration the clinical Hunt-Hess grade. Patients with lower grades usually have normal ICP, but patients with higher grades tend to have higher ICPs, and these patients tolerate hypotension poorly. This has also to be balanced against the risk of myocardial ischemia in patients with CAD or critical aortic stenosis. The use of high dose narcotics during induction is common to prevent the rise in blood pressure with intubation. Although succinylcholine has been reported to cause an increase in ICP, it has been successfully used in many aneurysm patients with no known sequelae. Many anesthesiologists tend to use nondepolarizing agents. In patients with a full stomach, the risk of aspiration must be balanced against the risk of aneurysm rupture.

In addition to standard GA monitors, monitoring should also include an arterial catheter, preferably placed before induction. Careful blood pressure management is needed during head pinning because this can also increase the blood pressure and potentially cause aneurysm rupture. A central venous catheter (CVC) is usually placed to manage the large fluid shifts and potential need for resuscitation. Placement of a CVC in the internal jugular vein should be discussed with the neurosurgeon because of the potential for venous obstruction to cerebral venous outflow. Placement of a PAC in patients with significant cardiac disease should also be considered. Other less frequently used monitors include jugular bulb oxygen saturation and transcranial Doppler.

The main goals during maintenance of anesthesia are to provide a “relaxed” brain, maintenance of cerebral perfusion, reduction in transmural pressure during final clipping of an aneurysm if necessary, and to allow early neurologic assessment if possible at the end of surgery. Sometimes the neurosurgeon requests cardiac standstill to facilitate clipping of a large aneurysm, and this can be achieved with a bolus of adenosine. This has to be done with extreme caution and is frequently contraindicated in patients with significant cardiac disease. Some large aneurysms may also require circulatory arrest with cardiopulmonary bypass.

Electrophysiology monitoring with electroencephalography, somatosensory and motor evoked potentials (SSEPs and MEPs) are sometimes used as additional monitoring tools. They may allow an intraoperative detection of cerebral ischemia.

The incidence of intraoperative rupture varies with the size and location of the aneurysm. Management of rupture during surgery depends on the ability to maintain blood pressure. If the leak is small, sometimes the surgeon is able to gain control with suction and permanent clipping. At other times, temporary clipping is needed to gain control. Communication between the surgeon and anesthesiologist regarding optimal management of emergence and postoperative management is essential (e.g., early extubation to assess neurologic status versus airway protection for patients who come in for emergent surgery).

Anesthetic Management of Patients With Emergencies in Interventional Neuroradiology

Interventional neuroradiology is the discipline that uses endovascular methods to treat vascular conditions of the central nervous system (CNS). Common goals in the anesthetic management of patients in interventional neuroradiology include maintaining immobility during the procedure, rapid recovery to assess neurologic function, managing anticoagulation, treating and managing unexpected procedure-related complications, and medical management of transportation. Although some of the procedures done in interventional neuroradiology tend to be of an elective nature, two common emergencies are intracranial aneurysm ablation and thrombolysis or thrombectomy of acute stroke.

Intracranial Aneurysm Ablation

The two basic approaches are occlusion of the proximal parent artery and obliteration of the aneurysmal sac. Patients with aneurysmal subarachnoid hemorrhage often have increased ICP or decreased compliance, usually caused by the subarachnoid hemorrhage, hydrocephalus, or parenchymal injury.

The management of these cases involves being prepared for aneurysmal rupture and a new acute subarachnoid hemorrhage at all times. This can happen from spontaneous rupture of a leaky sac, injury from vascular manipulation, or arterial occlusion. The morbidity and mortality rates are high for an intraprocedural rupture. If a rupture does occur, anticoagulation must be quickly reversed, and cerebral perfusion pressure must be maintained at adequate levels. Most patients develop a Cushing response, with hypertension and bradycardia. Emergency placement of an external ventricular drain by the surgeon must be considered, and emergency imaging should be obtained to assess extent of damage and to plan further management.

Thrombolysis and Thrombectomy of Acute Thromboembolic Stroke

In an acute thromboembolic stroke, attempts are made to recanalize the occluded vessel by highly selective intraarterial thrombolytic therapy using agents that are delivered in high concentration through a microcatheter that is navigated close to the clot. Neurologic deficits may be reversed if treatment is completed within several hours of onset of ischemia in the carotid territory and somewhat longer if ischemia is in the vertebrobasilar territory. Another new method is to remove the thromboembolic material from the vessels using retrieval devices.

Both tissue plasminogen activator administration and retrieval with a device have the risk of promoting hemorrhage. Anesthetic challenges involved in the acute care of these patients are that they are generally older, and commonly little is known about their comorbidities. These types of cases can be done under GA or sedation. The options have to be carefully considered, weighing the ability to monitor neurologic status and the risk of patient agitation and movement. Most of these patients also have vasculopathy and systemic hypertension. This can complicate the management because frequently there is the need to maintain MAPs at higher levels because of inadequate collateral circulation, and balancing the risk of vessel rupture or clot propagation.

Special Considerations in Anesthetic Management