Page 1632 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 119: Spinal Injuries 1151

establish the efficacy of systemic hypothermia in terms of functional HEALTH CARE–ASSOCIATED INFECTIONS
recovery. 79
Similar to other critically ill patients, SCI patients are susceptible to
health care–associated infections, which include central line–associated
SEDATION ISSUES bacteremia and wound infections. In addition, they are particularly
Acutely injured critically ill patients intubated on mechanical ventilation prone to retained secretions, narrowing of airway diameter with
require analgesia and sedation. Due to the nature of the neurological bronchoconstriction, and atelectasis. Ventilator–associated pneumonia
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injury, some acute SCI patients may be relatively free from pain and need (VAP) can be a difficult diagnosis to establish with certainty since
very little analgesia. However, some patients may have significant neu- fever and leukocytosis are nonspecific in critically ill patients and CXR
5
ropathic pain at or below the level of the injury, pain at the site of spinal infiltrates due to mucous plugging or acute lung injury may be confused
fracture, or pain from other concomitant traumatic injuries. Hypersensitivity with VAP. Unnecessary antibiotic therapy may increase the selection of
to dynamic touch or allodynia, more often seen in patients with incomplete resistant organisms. Biomarkers of infection such as serum procalcito-
cervical injuries, may present within minutes of injury but will usually nin may be useful in differentiating inflammation from infection after
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diminish over weeks to months. Avoiding brushing against the particular acute SCI, but further studies in critically ill SCI patients are needed
supersensitive dermatomes can help minimize allodynia. before evidence-based recommendations can be made. When antibiotics
All awake and responsive patients should have adequate analgesia, but are given, local antibiograms based on local susceptibility patterns
sedation may be minimized or via short-acting agents during periods should be utilized.
where the neurological exam needs frequent monitoring. In patients
that are not fully conscious or are severely agitated, sedation should take
preference since the neurological exam will not be possible regardless. VENOUS THROMBOEMBOLISM
Intoxicated patients may become very agitated and require sedation Both spine fractures and acute SCI increase the risk of venous thrombo-
even to the point of intubation in order to provide adequate assessment embolism (VTE). Among trauma patients, the risk of VTE is likely the
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and treatment. highest after acute spinal cord injury and may be in the 8% to 10% range
Commonly used agents include intravenous benzodiazepines such in patients requiring surgery. Risk factors are related to stasis, hyperco-
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as midazolam or propofol, and opioids such as fentanyl. Short-acting agulability, and intimal injury and include: tetraplegia versus paraplegia,
sedatives, used in the short term, for example, first 3 to 4 days, such as complete versus incomplete injury, associated extremity fractures and
propofol allow periodic neurological assessment and may be preferred. cancer, delayed initiation of thromboprophylaxis, and older age. SCI
Dexmedetomidine, a central α -agonist, is potentially useful as it allows patients not receiving VTE prophylaxis have the highest incidence of
2
for easy arousal, provides an analgesia sparing effect, and does not sup- deep vein thrombosis (DVT) among all hospitalized groups and pulmo-
press respiration. However, dexmedetomidine may cause or exacerbate nary embolism (PE) is the third leading cause of death. 90
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bradycardia in the SCI patient prone to bradyarrhythmia. Haloperidol The timely application of VTE prophylaxis is a major concern after
81
is often effective in controlling agitation either alone or in combination SCI. Low-dose unfractionated heparin and intermittent pneumatic com-
with the agents noted above. pression (IPC) devices alone are ineffective prophylaxis after SCI. 90,91
Low molecular weight heparin (LMWH) appears to be substantially
NUTRITIONAL SUPPORT ISSUES more efficacious; however, anticoagulants carry the risk of bleeding. The
current recommendations for VTE prophylaxis after SCI are starting
The caloric requirements after acute SCI do not appear to be above LMWH as soon as safely possible, after primary hemostasis is achieved.
89
normally predicted levels and may be initially depressed. Acute SCI Both LMWH and IPC devices may also be used simultaneously. The
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is associated with a negative nitrogen balance correlated with the extent application of IPC devices (or graded compression stockings) alone is
of myelopathy or of neurological injury, and protein administration in recommended only if the bleeding risks are too high for LMWH. After
the amount of 2 g/kg of ideal body weight and aggressive caloric delivery incomplete SCI with imaging evidence of spinal hematoma, the use of
does not appear to alter this negative pattern. Patients with high cervi- mechanical thromboprophylaxis instead of anticoagulant thrombopro-
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cal injury and prolonged ventilatory failure with tracheostomy are at a phylaxis is recommended for at least for the first few days after SCI. 90
higher risk of malnutrition. The enteral route is preferred to preserve The insertion of prophylactic IVC filters after acute SCI is not
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gut integrity. If prolonged delays in oral intake are anticipated, a naso- recommended. Although the risks of VTE are greatest in the acute
89
gastric or orogastric tube is placed and initiation of an enteral formula phase, DVT and PE occur during rehabilitation as well. For patients
within 24 to 48 hours after admission is recommended. If prolonged undergoing rehabilitation following acute SCI, continuation of LMWH
5
inability to swallow or high aspiration risk, percutaneous endoscopic or conversion to an oral vitamin K antagonist with INR target 2.5
gastrostomy tube placement is recommended. Most critically ill patients (range, 2.0 to 3.0) is recommended. Most VTE after acute SCI occurs
90
require between 20 to 30 kcal/kg ideal body weight to meet the daily within the first 91 days; therefore, 3 months of VTE prophylaxis is
energy expenditure. Under conditions of severe stress, requirements recommended for most patients. Doppler ultrasound screening is
89
may approach 30 kcal/kg ideal body weight. Parenteral nutrition should recommended in SCI patients who have received suboptimal thrombo-
be reserved for patients with intestinal complications that either con- prophylaxis or no thromboprophylaxis. 90
traindicate or interfere with enteral feeding. A metabolic cart (indirect Pulmonary embolism (PE) is the third leading cause of death after
90
calorimetry) measurement may allow more precise determination of acute SCI and after any sudden hemodynamic compromise, unex-
caloric requirements and help to avoid over or under feeding. plained dyspnea, or hypoxemia, PE must be considered. Spiral CT
Swallowing function needs to be evaluated prior to oral feeding in any scanning is the current standard for PE diagnosis in patients that can
acute SCI patient with cervical spinal cord injury, halo fixation, cervical be safely transported to radiology. However, acutely or in the patient
spine surgery, prolonged intubation, tracheotomy, or concomitant TBI. too unstable for transport, beside ultrasound evaluation to evaluate
■ GLYCEMIC CONTROL the lower extremities for DVT the heart for indirect evidence of PE
including right heart strain can be helpful in sorting out the diagnostic
Neurologically injured patients may have increased susceptibility to possibilities. Transthoracic echocardiography (TTE) or transesophageal
hyperglycemia and hypoglycemia; however, the current literature does echocardiography (TEE) may be utilized, but TEE can more readily
not support the maintenance of strict normoglycemia in these critically visualize the proximal pulmonary arteries and can rule in PE if proximal
ill patients. Glucose levels in target range of 120 to 180 mg/dL appear thrombus is identified. IVC filters are indicated after acute SCI with
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to be reasonable in critically ill patients. documented DVT or PE when anticoagulation is contraindicated.

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