The Journal of critical illness最新文献

Consider a do-not-resuscitate (DNR) order when a patient's presumed consent for cardiopulmonary resuscitation (CPR) is in question, the patient has an illness that is terminal or severe and irreversible, or he or she is permanently unconscious or likely to have cardiac or respiratory arrest. The patient with decisional capacity has the right to give or withhold consent for a DNR order. State law may limit a surrogate's authority to request that CPR be withheld. Remember, a DNR order does not restrict a patient's access to intensive care. Nurses, patient advocates, social workers, and clergy members may help mediate disputes. If necessary, seek advice from an ethics committee on how to resolve the conflict.

For patients with less severe coronary artery disease, particularly one- or two-vessel disease, initial therapy may be with either thrombolytics or angioplasty. In those with more extensive disease (three-vessel or left main artery disease or proximal left anterior descending artery stenosis), bypass grafting can significantly reduce mortality. However, a patient's risk profile markedly influences outcome regardless of the procedure performed. Because angioplasty achieves incomplete revascularization, patients may need repeated angiography or revascularization, or they may have recurrent angina. If bypass graft disease is prevented, surgery may be effective for up to 20 years.

Severe anxiety can disrupt neurohumoral metabolism and lead to agitation and brain failure, which may result in delirium. Predisposing factors include cerebral vascular or endocrine insufficiency, cardiopulmonary decompensation, poor tissue perfusion, multiple medications, and sleep-wake cycle disruption; the stressful ICU environment puts patients especially at risk. Stress-induced noradrenergic hyperactivity can precipitate panic attacks; dopaminergic hyperactivity can lead to delirium (marked by paranoid delusions, visual or auditory hallucinations, and psychomotor agitation). The underlying cause of anxiety must be identified to guide appropriate therapy.

Gastric tonometry is a noninvasive technique for early detection of splanchnic ischemia. Some studies have found that measurement of intramucosal pH (pHi) is able to predict outcome in critically ill patients. However, factors unrelated to splanchnic ischemia (for example, the presence of acid-base disorders or an intraluminal source of carbon dioxide) may skew results. Furthermore, accurate pHi measurement requires administration of an H2 blocker 60 to 90 minutes before patients undergo the procedure. Therefore, the role of gastric pHi in guiding therapy remains undefined.

Tracheotomy can relieve upper airway obstruction, improve pulmonary hygiene, and support long-term mechanical ventilation. Consider performing a tracheotomy whenever the need for more than 14 days of ventilatory support is anticipated. When emergent airway access is needed and translaryngeal intubation is not possible, consider cricothyroidotomy. For a tracheotomy, make a transverse incision 1 cm above the suprasternal notch or, for cricothyroidotomy, through the superficial cricothyroid membrane. Accidental tube displacement within 5 days of surgery is potentially tracheotomy's most lethal early complication. Many late complications can be prevented by careful management and expert nursing support.

A number of factors must be considered when selecting a revascularization strategy for a patient with CAD: Is the patient's condition stable or unstable? How many vessels are affected? What are the benefits and drawbacks of each technique? For patients with an evolving infarction, either thrombolysis or PTCA can achieve early reperfusion. PTCA is also often helpful for those with one- or two-vessel disease; however, restenosis develops in 30% to 50% of patients, usually within 6 months. Although CABG can produce excellent long-term results for patients with three-vessel or left main artery disease and for those with proximal stenosis, the risk of perioperative complications and bypass graft disease remains significant.

When a patient is admitted to the ICU, determine whether the person has decisional capacity and whether an advance directive exists. If so, discuss treatment options and the directive with the patient--as well as with family members and appointed surrogates; clarify the patient's wishes. If no directive has been drawn up, encourage the patient to do so. If a patient lacks decisional capacity but has a directive, determine whether it applies to the current situation. If it does, follow its instructions. If no directive exists or if it does not apply, consult with family members to determine the patient's wishes, and ascertain whether these substitute judgments meet state laws.

When arterial cannulation is required, but the radial artery cannot be used, five alternatives can be considered: the ulnar, brachial, axillary, femoral, and dorsalis pedis arteries. Of these, the dorsalis pedis may be the next best choice: Collateral flow is excellent, and cannulation here is easy to perform, presents minimal patient inconvenience, and has a very low incidence of complications. Systolic pressure readings obtained at the dorsalis pedis artery are 5 to 20 mm Hg higher than measurements obtained at the radial artery; however, by comparing the dorsalis pedis reading with a cuff pressure, you can quickly determine the extent of overshoot and correct the invasive measurement.

Postoperative hypertension, though transient, requires immediate attention. Clinical variables include the patient's preoperative blood pressure, medications, and acute medical status; the surgical procedure performed; and the physiologic changes induced by surgery. Evaluate and treat any reversible causes of hypertension. Initiate drug therapy when organ failure or dysfunction is present or when the patient is at high risk for such complications. In choosing an agent, look for ease of administration, titratability of blood pressure response, rapid onset and cessation of action, and a low incidence of adverse effects. Options are nitrovasodilators, calcium channel blockers, ACE inhibitors, direct-acting vasodilators, adrenergic blockers, and neuromodulators (narcotics and anesthetics).