The Journal of critical illness
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Percutaneous tracheostomy is the procedure of choice for most patients who require prolonged use of an artificial airway; it can be performed rapidly at the bedside and is associated with fewer complications than is the standard procedure. The serial dilational technique involves the insertion of prelubricated dilators that gradually enlarge the diameter of a tract made by a guidewire and guiding catheter, facilitating placement of a standard double-cannula tracheostomy tube. The most dangerous complication, paratracheal insertion, occurs only rarely. The small skin incision and resulting tight fit of the tracheostomy tube in the stoma help prevent bleeding and infection.
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A variety of methods have been employed to help wean patients from prolonged ventilatory support. Although synchronized intermittent mandatory ventilation is probably the most widely used, it has not been shown to be clearly superior to T piece or pressure support weaning. ⋯ The patient's response to the change in the level of ventilatory support governs the rapidity of weaning. The rapid shallow breathing index can be useful in predicting weaning outcome, as is the patient's ability to tolerate a weaning trial.
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Fiberoptic bronchoscopy has a variety of applications in the intensive care unit. This procedure, which can be done at the patient's bedside, can be used to clear excess secretions; check the position of, or replace, an endotracheal tube; identify areas of active bleeding; diagnose opportunistic infections; and evaluate obstructive airway lesions. ⋯ In intubated, ventilated patients, a fiberoptic bronchoscope may be passed through a swivel adapter to prevent loss of the delivered oxygen and tidal volume. Cardiac arrhythmias and hypoxemia are among the most common complications.
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Inverse ratio ventilation (IRV) differs from other ventilatory techniques in that it employs a prolonged inspiratory time. In theory, pressure-control IRV allows you to maintain ventilation and oxygenation with lower peak airway and end-expiratory pressures; this may reduce the potential for lung damage secondary to shearing forces. ⋯ Currently, the chief limitation of this technique is that the patient cannot breathe spontaneously during its use. The best inspiratory to expiratory ratio is the shortest inspiratory time that improves oxygenation with minimal hemodynamic compromise; depression of cardiac output will negate any potential improvement in arterial oxygenation.
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In the ICU, both transthoracic and transesophageal echocardiography can assist in the acute management of a number of different disorders. In hypotensive patients, echocardiography helps distinguish between cardiogenic shock (resulting from acute myocardial infarction), septic shock, and circulatory shock (associated with a reduction in circulating blood volume); it can also help determine whether pericardial effusion or obstruction to valvular flow is producing the hypotension and suggesting pulmonary embolus. Other roles for echocardiography include differentiating left- and right-sided heart failure, assessing the extent of pericardial disease, diagnosing disorders of the thoracic aorta, and evaluating traumatic heart disease.