What the Anesthesiologist Should Know before the Operative Procedure
Patients with traumatic brain injury (TBI) suffer from both the primary injury and also secondary injuries that exacerbate the damage and worsen their outcome. Primary injury is damage caused by the mechanical impact of brain tissue and the skull, resulting in skull fracture, brain contusion, intracranial hematoma, or diffuse axonal injury.
Secondary injury is a consequence of systemic extracranial and intracranial insults that develop over time after the onset of the initial injury, such as hypotension (systolic blood pressure, SBP < 90 mmHg), hypoxemia (PaO2 < 60 mmHg), hypoglycemia, hyperglycemia, hypocarbia, and hypercarbia. Intracranial injuries include hematoma, edema, increased intracranial pressure (ICP), and seizure.
The preoperative period is important for the management of TBI because surgery and anesthesia may induce secondary injury. The anesthetic management involves continuation of initial resuscitation and airway management, as well as prevention and rapid correction of secondary injuries.
The management of TBI patients can be challenging and complicated by associated extracranial injuries, co-existing hypovolemia, and neurogenic shock. Patients undergoing extracranial surgeries who have TBI may suffer from secondary injuries due to blood loss or anesthesia. Typically, elevated ICP is a relative contraindication to extracranial surgery, except when a patient’s life is at risk.
1. What is the urgency of the surgery?
What is the risk of delay in order to obtain additional preoperative information?
Surgical procedures for TBI include craniotomy for evacuation of epidural, subdural, or intracerebral hematomas and decompressive craniectomy for the treatment of intracranial hypertension refractory to medical treatment. In patients with indications for surgical evacuation of intracranial hematoma, craniotomy should be performed as soon as possible because delaying surgery is associated with neurological dysfunction and poor outcome.
Surgery for TBI is never elective. Urgent craniotomies give the anesthesiologist some time to prepare for the patient’s arrival, whereas emergent craniotomy typically suggests increased ICP that may be associated with Cushing’s triad of hypertension and bradycardia. Issues related to urgent or emergent craniotomy include the need for adequate vascular access, availability of blood products, and the ability for rapid resuscitation.
Decompressive hypotension is a relatively frequent occurrence during the evacuation of intracranial masses, and is thought to be due to an evacuation-mediated decrease in blood pressure. Anticipated complications of urgent/emergent craniotomies include hypotension, coagulopathy, hypo or hyperthermia, hyperglycemia, and iatrogenic, but unwanted, hypocarbia.
2. Preoperative evaluation
The preanesthetic assessment of TBI patients includes examination of:
Airway and cervical spine stabilization
Breathing, with attention paid to oxygenation and ventilation
Circulation, with attention paid to blood pressure
Disability with rapid assessment of neurological status
Associated extracranial injuries, such as chest, abdominal, pelvic, and long bone injuries
Pre-existing chronic illnesses, such as congestive heart failure, diabetes, and associated medication use
Circumstances of the injury, including the time of injury, duration of unconsciousness, and associated alcohol or drug use
A brief neurological assessment can be performed using the Glasgow Coma Scale (GCS) score and examination of pupil response. A GCS < 9 reflects severe TBI, a GCS score of 9-13 reflects moderate TBI, and a GCS score of 14-15 reflects mild TBI.
Medically unstable conditions warranting further evaluation are rare since craniotomy for TBI is typically urgent or emergent.
Delaying surgery may be indicated due to the urgent/emergent nature of TBI. However, a number of TBI patients suffer from associated injuries and may require extracranial surgery. The decision of which surgery to do first depends on several factors, including the severity of TBI, the severity of associated injuries, and the patient’s condition.
In the acute care setting, where patients have extracranial injuries and TBI, hemodynamic stability status guides further care. For example, if hemodynamics are stable with the ongoing resuscitation, there may be sufficient time to perform a head CT scan prior to urgent/emergent laparotomy. If hemodynamics are unstable, patients may undergo emergent surgery without a head CT scan, and the presence of a TBI may have to be assumed, especially if the mechanism of injury suggests it.
If patients have lateralizing signs, and the head CT scan shows a surgical lesion, then patients may need to have simultaneous emergent craniotomy and laparotomy. It is reasonable and may be desirable to request intraoperative ICP monitoring for patients with TBI who undergo extracranial surgery, such as orthopedic operative fixation.
3. What are the implications of co-existing disease on perioperative care?
Co-existing conditions may impact the surgical and postoperative course. For patients with co-existing diseases, such as elderly patients who sustain falls, particular attention should be paid to preinjury cardiac, pulmonary, and endocrinological status.
Congestive heart failure, hypertension, chronic obstructive pulmonary disease, or type II diabetes are common in this population, and may result in intraoperative and postoperative cardiac complications, CO2 retention, or hyperglycemia, and may adversely impact short and long term outcomes. In particular, rapid administration of coagulation products (such as fresh frozen plasma or platelets) is desirable for patients who are preoperatively treated with anticoagulants or antiplatelet agents.
b. Cardiovascular system
i. The perioperative evaluation should focus on identifying serious cardiac conditions, such as unstable coronary syndromes, decompensated heart failure, significant arrhythmias, and severe valvular disease. The physical examination should include vital signs, carotid pulse and bruits, auscultation of heart and lungs, and examination of extremities for edema.
ii. Since craniotomy for TBI is typically urgent or emergent, patients should proceed with the surgery without additional cardiac evaluations, such as an EKG. The focus should be on perioperative surveillance and postoperative risk stratification and risk factor management.
Baseline coronary artery disease or cardiac dysfunction – Goals of management:
i. Perioperative evaluation should determine the presence and severity of baseline cardiac disease, the patient’s functional capacity, current medications, history of pacemaker or implantable cardioverter defibrillator (ICD), and associated diseases, such as cerebrovascular disease, diabetes mellitus, and renal impairment.
ii. Perioperative risk reduction strategies involve perioperative surveillance for myocardial infarction (MI), ischemia, and arrhythmia and risk reduction strategies. The perioperative surveillance for MI includes serial EKG, ST-segment monitoring, and troponin measurement. Strategies to modify risks include perioperative ß-blocker and statin therapy, heart rate and glucose control, and postoperative pain management.
During the perioperative evaluation, history should determine the severity of the disease, frequency of exacerbation, supplemental oxygen, hospitalization, intubation, change in amount and color of sputum or other signs of infection, medication, and coexisting cardiac disease. Physical examination should focus on the quality of breath sound, air movement, and the presence of wheezing, rhonchi, and rales. Chest radiography may be useful in detecting infection or lung bullae. Arterial blood gas is useful to establish baseline oxygenation, carbon dioxide, and acid-base balance.
Perioperative risk reduction should aim to prevent bronchospasm and appropriate ventilator setting to minimize airway pressure and avoid air trapping. Preooperative bronchodilators may be beneficial and should be given. Supplemental systemic steroids may be needed in patients on chronic steroid therapy.
Reactive airway disease (Asthma):
The perioperative history should determine the severity of disease, recent exacerbation, hospitalization, intubation, and the current therapy. The physical examination should focus on detecting signs of acute exacerbation and active lung infection. A chest x-ray may be useful for evaluation of infection, air trapping, and pneumothorax. Pulse oxymetry is useful in determining oxygen saturation. In severe cases, arterial blood gas analysis may be necessary.
The goal of perioperative risk management is to avoid perioperative bronchospasm, which can be provoked by a number of factors, such as airway procedures and histamine-release medications. Prophylactic bronchodilators could be given by either MDI or nebulizer prior to the OR. Perioperative systemic steroids may be beneficial for patients who are not at a baseline condition or on chronic steroid therapy.
i. The perioperative evaluation should focus on renal function, volume, and electrolyte status, as well as associated cardiovascular and other coexisting diseases, medication, and analysis. In patients on hemodialysis, the site of arteriovenous fistula should be identified and blood pressure and venous access should be avoided in that arm.
ii. The primary goal of perioperative risk reduction management for patients with renal insufficiency is to preserve renal function by avoiding nephrotoxic agents and administering hydration fluids, diuretics (mannitol, furosemide), and low-dose dopamine.
i. During the perioperative evaluation, be aware that Diabetes mellitus, especially type II, is a common endocrine disease for elderly patients. The preoperative evaluation of diabetes should focus on control of blood glucose and end-organ damage, including cardiovascular, renal, and neurological systems. The control of blood glucose can be determined by the glysolated hemoglobin (HbA1c) level. Preoperative EKG, chest radiography, blood glucose, BUN, creatinine, and electrolytes are recommended.
ii. Perioperative risk reduction strategies include several perioperative blood glucose management regimens, however, the primary goals are to avoid hypoglycemia, hyperglycemia, ketoacidosis, and hyperosmolar state. Intensive insulin therapy or tight control aims to keep plasma glucose between 80 to 120 mg/dl, whereas conventional regimen aims to keep plasma glucose below 220 mg/dl. During the perioperative period, blood glucose should be monitored closely and efforts should be made to prevent hypo and hyperglycemia.
g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)
4. What are the patient's medications and how should they be managed in the perioperative period?
A number of TBI patients are elderly and receive medications to treat coexisting diseases, such as antihypertensive drugs, antiplatelet drugs, and oral hypoglycemic drugs. Many of these medications have side effects that may affect the anesthetic management. A careful medication history should be obtained, including non-prescribed medications, vitamins, and herbal supplements.
h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
Diuretics can cause electrolyte imbalance, resulting in arrhythmia. Patients who receive ß-blocker may experience bradycardia and experience failure to increase their heart rate in response to blood loss. Calcium channel blockers may cause hypotension, especially when combined with ß-blockers. ACE inhibitors or angiotensin II antagonists (AIIAs) are associated with refractory hypotension, especially when combined with diuretics.
Antiplatelet and anticoagulant drugs:
Patients who receive antiplatelet or anticoagulant drugs may have an increased risk of bleeding and transfusion. Perioperative transfusion of 2 to 5 units of platelet concentrates may be required to return platelet function to an adequate level. Emergency reversal of oral anticoagulant could be achieved by administration of vitamin K therapy with fresh frozen plasma, prothrombin complex concentrates (PCCs), or recombinant factor VIIa (rfVIIa).
Oral hypoglycemic drugs:
Patients who receive oral hypoglycemic drugs may develop perioperative hypoglycemia.
Garlic, ginseng, ginger, and gingko are commonly used herbals which may interfere with platelet function, particularly when combined with NSAIDs or warfarin, and increase the risk of bleeding. Ginseng also has a hypoglycemic effect and may cause intraoperative hypoglycemia, especially in patients who receive oral hypoglycemic drugs.
i. What should be recommended with regard to continuation of medications taken chronically?
Due to the urgency of the surgery, there is no time to discontinue medications beforehand. Medication reconciliation is an important part of quality and safe care during the post-operative period.
j. How To modify care for patients with known allergies –
A careful history and medical record review is important to identify patient risk factors or history of allergy. The key is to avoid known triggering agents.
k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.
If latex allergy is suspected, the operating room (OR) should be latex-free. It is recommended that all staff wear non-powdered, non-latex gloves. All medical products should be made of non-latex material. There should be a latex allergy resuscitation cart available in or near the OR. All drugs should be in glass ampuls and all syringes should be glass syringes or syringes with latex-free plungers. Prophylactic steroid or H1 and H2 receptor antagonists are not recommended.
l. Does the patient have any antibiotic allergies- – Common antibiotic allergies and alternative antibiotics]
Cefazolin is the prophylactic antibiotic of choice for craniotomy, but if the patient has ß-lactam allergy, Clindamycin 600-900 mg or Vancomycin 1 g intravenous are suitable alternatives.
m. Does the patient have a history of allergy to anesthesia?
avoid all trigger agents such as succinylcholine and inhalational agents:
Proposed general anesthetic plan:General anesthesia using total intravenous anesthesia (TIVA) technique without succinylcholine is safe. The anesthetic machine should be cleansed by a fresh gas flow 10L/min for 5 minutes and a disposable circuit should be used. All vaporizers should be removed, and the soda lime should be changed. MH cart with dantrolene should be available for immediate use.
Family history or risk factors for MH:
If the patient has family history or risk factors of malignant hyperthermia, anesthesia should be given in the same fashion as a known malignant hyperthermia patient.
Local anesthetics/ muscle relaxants:
If the patient has a history of allergy to local anesthetics or muscle relaxants, all such drugs must be avoided. If the patient had an unexplained reaction during a previous anesthesia, anesthesia should be given without muscle relaxants in a latex-free environment.
5. What laboratory tests should be obtained and has everything been reviewed?
Complete blood count, hemoglobin, and hematocrit should be obtained due to the potential blood loss and risk of developing coagulopathy as a complication of TBI.
Electrolytes and glucose should be obtained.
Coagulation testing should be obtained, due to the potential for blood loss and risk of developing coagulopathy.
A chest radiography should be obtained to assess associated injuries.
Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?
General anesthesia with endotracheal tube and controlled ventilation is recommended for better control of cardiovascular and respiratory function.
The major goals of anesthetic management of TBI are to:
maintain cerebral perfusion pressure (CPP)
provide adequate surgical conditions
avoid secondary injuries from hypotension, hypoxia, hyper and hypocarbia, hyper and hypoglycemia
provide adequate analgesia and amnesia
Most TBI patients requiring surgery are intubated when they arrive in the OR. In these patients, an adequate position of the endotracheal tube must be confirmed. In patients who are not already intubated, airway management can be complicated by several factors, including:
a full stomach
uncertain cervical spine status
uncertain airway status airway injury, blood, vomitus, skull base fracture)
uncertain volume status
uncooperative or combative patient
All TBI patients requiring urgent surgery must be considered to be full stomach with possible underlying cervical spine injury. The choice of intubation technique is determined by these factors, personnel experience, and available resources. In general, rapid sequence induction with cricoid pressure followed by direct laryngoscopy and tracheal intubation with manual-in-line immobilization (MILI) is recommended.
If a cervical collar is in place, the anterior portion can be removed when MILI is established to allow greater mouth opening and facilitate direct laryngoscopy. It is reasonable to have emergency airway equipment available and ready to use in case of failed intubation, because the injured brain is intolerant to hypoxia, hybercarbia, and increased ICP.
In patients who have facial fractures or soft tissue edema that prevent direct visualization of the larynx, fiberoptic intubation can be performed. If the facial fractures are severe or laryngeal trauma is present, cricothyroidotomy may be required. Nasal intubation should be avoided in patients with base of skull fracture, severe facial fractures, or bleeding diathesis.
The choice of induction agent depends on the patient’s hemodynamic status. Sodium thiopental, etomidate, and propofol are commonly used to induce anesthesia before intubation. All of these agents decrease the systemic hemodynamic response to intubation, decrease ICP, and decrease the cerebral metabolic rate for oxygen (CMRO2).
Propofol and thiopental can cause cardiovascular depression, leading to hypotension, especially in the presence of uncorrected hypovolemia. Hence, etomidate may be preferable for hemodynamically unstable patients due to fewer changes in blood pressure. Ketamine causes limited cardiovascular changes, but increases cerebral blood flow (CBF) and ICP. Therefore, it may be contraindicated for TBI patients.
Muscle relaxants for rapid sequence induction are succinylcholine and rocuronium. Succinylcholine may be associated with an increased ICP which can be attenuated by administering an adequate dose of induction agent. Moreover, clinical significance of the effect of succinylcholine on ICP is inconclusive. For this reason, succinylcholine should not be contraindicated in TBI patients.
6. What is the author's preferred method of anesthesia technique and why?
Inhalation vs. IV Anesthesia
All volatile anesthetic agents (Isoflurane, Sevoflurane, and Desflurane) decrease CMOR2 and may cause cerebral vasodilation, resulting in increasing CBF and ICP. However, at a concentration less than 1 MAC (minimum alveolar concentration), the cerebral vasodilatory effects are minimal, and hence they may be used in low concentrations in patients with TBI. Nitrous oxide should be avoided due to increased CMRO2 and ICP from cerebral vasodilatation.
Intravenous agents, including thiopental, propofol, and etomidate, cause cerebral vasoconstriction and reduce CBF, CBV, CMRO2 and ICP. Opioids have no direct effect on cerebral hemodynamics in the presence of controlled ventilation. Muscle relaxants have little or no effect on CBF and ICP. The effects of choice of anesthesia (inhalation vs. total intravenous anesthesia) on outcome of TBI have not been demonstrated. The principles of anesthetic management should adhere to the guidelines for the management of severe TBI. (Table 1)
|Blood pressure||Monitor and avoid hypotension (SBP < 90 mmHg). (level II)|
|Oxygenation||Monitor and avoid hypoxia (PaO2 < 60 mmHg or oxygen saturation < 90%). (level II)|
|PaCO2||Prophylactic hyperventilation (PaCO2 ≤ 25 mmHg) is not recommended. (level II)Hyperventilation is recommended as a temporizing measure for the reduction of elevated ICP. (level III)|
|Temperature||Prophylactic hypothermia is not associated with decreased mortality compared to normothernic controls. There may be greater decrease in mortality risk when target temperatures are maintained for more than 48 hours. Prophylactic hypothermia is associated with higher GOS scores compared to normothermic controls (Level III).|
|Intracranial pressure (ICP)||Treat when ICP threshold > 20 mmHg. (level II)|
|Cerebral perfusion pressure||Keep CPP between 50-70 mmHg.Avoid aggressive treatment with fluid and pressors to maintain CPP > 70 mmHg. (level II) Avoid CPP < 50 mmHg. (level III)|
Treat when jugular venous saturation < 50% or brain tissue oxygen tension < 15 mmHg. (level III)
In addition to standard American Society of Anesthesiology (ASA) monitors, arterial catheterization is recommended for beat-to-beat blood pressure monitoring and for blood gas analysis and blood glucose monitoring during craniotomy. Central venous pressure (CVP) may be useful, particularly for resuscitation and when vasopressors are administered.
According to current guidelines, ICP monitoring is recommended in all salvageable patients with severe TBI who have an abnormal CT scan (hematomas, contusions, swelling, herniation, or compressed basal cistern) and in patients with severe TBI with a normal CT scan if two or more of the following features are noted at admission: age > 40 years, unilateral or bilateral motor posturing, or SBP < 90 mmHg. Monitoring cerebral oxygenation (global or focal) or cerebral blood flow and metabolism parameters may be useful for postoperative management.
What prophylactic antibiotics should be administered?
Utilize current SCIP recommendations s. Cefazolin 1-2 g intravenous should be given within 1 hour prior to surgical incision. If the patient has ß-lactam allergy, Clindamycin 600-900 mg or Vancomycin 1 g intravenous are alternative antibiotics. If there is known history of MRSA, Vancomycin 1 g intravenous is recommended
Blood Pressure Management
Hypotension can compromise CBF and is associated with poor outcome. According to the guidelines for the management of severe TBI, hypotension should be avoided. SBP should be maintained at > 90 mm Hg, and CPP should be maintained at between 50-70 mmHg. The 2003 pediatric guidelines recommend maintaining systolic blood pressure > 5th percentile and CPP > 40 mmHg.
Isotonic crystalloid solution is preferable for TBI patients. Glucose-containing solutions should be avoided. The role of colloid is controversial. Resuscitation with albumin is associated with a higher mortality rate and unfavorable outcomes. Hypertonic saline may be beneficial, due to an increased intravascular volume and a decreased ICP.
Oxygenation and Ventilation
Hypoxia, hypercarbia, and hypocarbia should be avoided. Oxygenation should be monitored and maintained at PaO2 > 60 mmHg or oxygen saturation > 90%. Hyperventilation causes cerebral vasoconstriction and can result in ischemia. The current guidelines for the management of TBI indicate that prophylaxia hyperventilation (PaCO2 ≤ 25 mmHg) is not recommended and hyperventilation should be avoided during the first 24 hours after the injury when CBF is often critically reduced. Hyperventilation is recommended as a temporizing measure for the reduction of elevated ICP.
Mannitol is the standard treatment of hyperosmolar therapy. The recommended dose of mannitol is 0.25 – 1 gm/kg body weight. Mannitol is recommended only if there are signs of transtentorial herniation or progressive neurological deterioration not attributable to extracranial causes because of the osmotic diuresis effect, which can result in hypovolemia and hypotension and can lead to secondary brain injury. In patients with severe TBI and elevated ICP, an alternate therapy is 3% hypertonic saline (1.5 ml/kg or 50-100 ml/hour), which can be used as a second tier therapy, titrated to a sodium of 155-160 meq/L.
Hyperglycemia is a stress response to the injury and is associated with increased morbidity and mortality. To date, there is no guideline suggesting the optimal glucose level, and intensive insulin therapy is controversial. Van den Berghe et al. reported that intensive insulin therapy (target blood glucose 80-110 mg/dl) in critically ill patients was associated with lower mortality. However, more recent studies failed to demonstrate the mortality benefit of intensive insulin therapy but found an increased risk of hypoglycemia.
Billotta et al. randomized 97 severe TBI patients to either intensive insulin therapy, targeting blood glucose levels at 80-120 mg/dl, or conventional insulin therapy, targeting blood glucose levels below 220 mg/dl. They found that both groups had similar mortality and neurological outcomes at 6 months. Although the intensive insulin therapy group had shorter ICU stays, infection rates were similar between both groups, and episodes of hypoglycemia (blood glucose < 80 mg/dl) were significantly higher in the intensive insulin therapy group.
It is reasonable to keep blood glucose levels at 80-180 mg/dl and to check blood glucose at least once every hour to detect hyper or hypoglycemia.
Hypothermia reduces cerebral metabolism during stress, reduces excitatory neurotransmitters, and attenuates blood-brain barrier (BBB) permeability. A meta-analysis in 2008 found that prophylactic hypothermia was not significantly associated with decreased mortality and increased favorable neurological outcome in TBI patients. The benefits of hypothermia were greater when cooling was maintained for more than 48 hours. However, the benefits may be offset by the risk of pneumonia and arrhythmia. According to the guidelines for the management of severe TBI, prophylactic hypothermia is a level III recommendation.
High-dose methylprednisolone is contraindicated in patients with moderate or severe TBI. Administration of methylprednisolone within 8 hours of TBI has been shown to be associated with higher risk of death and the risk of severe disability.
Both anemia and red blood cell (RBC) transfusion are associated with poor outcome in TBI. Anemia is associated with increased mortality rates and lower Glasgow Outcome Scale at hospital discharge. RBC transfusion is associated with acute lung injury, longer intensive care unit and hospital stays, and mortality. Currently, the optimal hemoglobin level in TBI patients is still unclear. However, there is no benefit to a liberal transfusion strategy (transfusion when hemoglobin (Hb) < 10 gm/dl) in moderate to severe TBI patients, and so it is not recommended.
Hypotension may occur after dural opening during the surgical evacuation of an intracranial mass. This may result from a sudden decrease of sympathetic tone, reversing the Cushing’s response after ICP is relieved. Moreover, hypotension also may be due to hypovolemia, resulting from either the administration of mannitol, bleeding from the surgical site, or associated injuries. Hypotension should be vigorously treated with intravenous fluids and blood replacement, if indicated, or vasopressor and inotrope administration.
This is a common problem after TBI. The overall prevalence of coagulopathy was reported to be 32.7% after TBI and more than 60% in severe TBI. Coagulopathy disorder could cause secondary brain injury from ongoing intracranial bleeding and can worsen the outcome. Disseminated intravascular coagulopathy (DIC) causes defective anticoagulation pathways by inhibiting the antithrombotic mechanisms.
At present, there is no guideline for the management of coagulopathy in TBI. Management of DIC usually involves platelets and blood component replacement. Hemostatic drugs, including antifibrinolytic agents such as tranexamic acid (TXA), and pro-coagulant drugs, such as recombinant activated factor VII (rFVIIa), are occasionally used in the treatment of coagulopathy after TBI. TXA has been shown to be associated with decreased mortality and decreased risk of death from bleeding in adult trauma patients. However, there is no evidence supporting the benefit of rFVIIa in TBI patients.
b. If the patient is intubated, are there any special criteria for extubation?
The decision to extubate the patient at the end of the surgery should be discussed with the surgeon. In addition to the general criteria for extubation, the decision to extubate TBI patients also depends on the severity of TBI, the preoperative level of consciousness, the associated injury, and hemodynamic status. If the patient is not able to meet these criteria, the patient should be transferred to the ICU with an endotracheal tube in place.
Coughing, straining, and hypertension during transportation may lead to intracranial bleeding. Hypertension can be treated with labetalol or esmolol and supplemental barbiturates or short acting benzodiazepines (midazolam).
c. Postoperative management
Most TBI patients require postoperative mechanical ventilation and should be transferred to the ICU. The management of TBI in the ICU should be guided by a protocol to optimize CPP and prevent secondary insults. Adequate analgesia and sedation reduces anxiety, agitation, and pain, as they can increase ICP. Adequate analgesia can be provided with continuous intravenous infusion of short-acting opioids, such as remifentanil or fentanyl. Commonly used sedatives include propofol, midazolam, and dexmedetomidine.
What are common postoperative complications, and ways to prevent and treat them?
Posttraumatic seizures (PTS):
PTS are classified as early, occurring within 7 days after injury, and late, occurring more than 7 days after injury. The incidence of early PTS ranged from 4 to 25%. Seizures increase CMRO2, neurotransmitter release, and ICP, and may worsen patient outcome.
Factors associated with increased risk of developing PTS are a GCS score < 10, cortical contusion, depressed skull fracture, subdural hematoma, epidural hematoma, intracerebral hematoma, penetrating head injury, and seizure within 24 hours of injury. Prophylactic anticonvulsants are indicated for preventing early PTS. Both phenytoin and valproate have been shown to be effective in reducing early PTS. However, valproate may be associated with a higher mortality.
Prophylactic anticonvulsants for late PTS are not recommended.
Deep Venous Thrombosis (DVT):
The incidence of DVT is associated with the type and severity of injuries. The risk of developing DVT was estimated to be 20% after severe TBI. Most DVT are asymptomatic; however, pulmonary embolism (PE) can be a consequence, particularly with DVT in proximal leg veins.
The guidelines for the management of severe TBI recommend the use of graduated compression or IPC stockings for DVT prophylaxis for patients with severe TBI, unless lower extremity injuries prevent their use. Use should be continued until patients are ambulatory. Low molecular weight heparin (LMWH) or low dose unfractionated heparin should be used in combination with mechanical interventions. However, there is insufficient data available regarding the timing and dose of pharmacological prophylaxis.
What's the Evidence?
Fischer, SP, Bader, AM, Sweitzer, B, Miller, RD. “Perioperative evaluation”. 2010. pp. 1011-66. (This book provides current knowledge and practices in the field of anesthesia.)
Bratton, SL, Chestnut, RM, Ghajar, J, McConnell Hammond, FF, Harris, OA, Hartl, R. “Guidelines for the management of severe traumatic brain injury”. J Neurotrauma. vol. 24. 2007. pp. S1-106. (Recommendations from these guidelines were developed based on current scientific evidence by a group of international experts in the field.)
Crosby, ET. “Airway management in adults after cervical spine trauma”. Anesthesiology. vol. 104. 2006. pp. 1293-318. (This article is an updated review on airway management in cervical spine injuries.)
Myburgh, J, Cooper, DJ, Finfer, S, Bellomo, R, Norton, R, Bishop, N. “Saline or albumin for fluid resuscitation in patients with traumatic brain injury”. N Eng J Med. vol. 357. 2007. pp. 874-84. (This study is a multicenter randomized controlled trial (RCT) with a large number of patients.)
Van den Berghe, G, Wouters, P, Weekers, F, Verwaest, C, Bruyninckx, F, Schetz. “Intensive insulin therapy in the critically ill patients”. N ENG J Med. vol. 345. 2001. pp. 1359-67. (The first prospective RCT that shows the benefit of intensive insulin therapy in critically ill patients.)
Billotta, F, Caramia, R, Cernak, I, Paoloni, FP, Doronzio, A, Cuzzone, V. “Intensive insulin therapy after severe traumatic brain injury: a randomized clinical trial”. Neurocrit Care. vol. 9. 2008. pp. 159-66. (The first prospective RCT providing evidence for the risks and benefits of intensive insulin therapy after severe TBI.)
Peterson, K, Carson, S, Carney, N. “Hypothermia treatment for traumatic brain injury: a systematic review and meta-analysis”. J Neurotrauma. vol. 25. 2008. pp. 62-71. (This article is the most recent meta-analysis of the effects of therapeutic hypothermia on the outcome after TBI.)
Edwards, P, Arango, M, Balica, L, Cottingham, R, El-Sayed, H, Farrell, B. “CRASH trial collaborators. Final results of MRC CRASH, a randomised placebo-controlled trial of intravenous corticosteroid in adults with head injury-outcomes at 6 months”. Lancet. vol. 365. 2005. pp. 1957-9. (CRASH trial is a large international RCT of the effects of methylprednisolone on TBI outcome. The study includes 10,008 patients.)
Napolitano, LM, Kurek, S, Luchette, FA, Corwin, HL, Barie, PS, Tisherman, SA. “Clinical practice guideline: red blood cell transfusion in adult traumatic and critical care”. Crit Care Med. vol. 37. 2009. pp. 3124-57. (The guideline was developed based on current scientific evidence by a group of international experts in the field.)
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- What the Anesthesiologist Should Know before the Operative Procedure
- 1. What is the urgency of the surgery?
- What is the risk of delay in order to obtain additional preoperative information?
- 2. Preoperative evaluation
- 3. What are the implications of co-existing disease on perioperative care?
- b. Cardiovascular system
- c. Pulmonary
- d. Renal-GI:
- e. Neurologic:
- f. Endocrine:
- g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)
- 4. What are the patient's medications and how should they be managed in the perioperative period?
- h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
- i. What should be recommended with regard to continuation of medications taken chronically?
- j. How To modify care for patients with known allergies -
- k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.
- l. Does the patient have any antibiotic allergies- - Common antibiotic allergies and alternative antibiotics]
- m. Does the patient have a history of allergy to anesthesia?
- 5. What laboratory tests should be obtained and has everything been reviewed?
- Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?
- 6. What is the author's preferred method of anesthesia technique and why?
- Inhalation vs. IV Anesthesia
- What prophylactic antibiotics should be administered?
- Blood Pressure Management
- Intravenous Fluids
- Oxygenation and Ventilation
- Hyperosmolar Therapy
- Glycemic Control
- Therapeutic Hypothermia
- Blood Transfusions
- Cardiac Complications:
- Neurologic Complications:
- a. Neurologic:
- b. If the patient is intubated, are there any special criteria for extubation?
- c. Postoperative management