might indicate an intratracheal granuloma, which should be evaluated by direct visualization, typically performed by an otorhinolaryngologist A large amount of bleeding is a surgical emergency IV access should be obtained immediately and volume replacement should be initiated The tracheostomy tube should not be removed because it may be the best way to ensure an airway Frequent suctioning aids in preventing aspiration If the site of bleeding can be identified, direct pressure should be applied to the area Overinflating the cuff may tamponade a bleeding vessel and provide a temporary treatment until it can be ligated Peristomal granulomas can usually be treated with topical antibiotics In refractory cases, cauterization with silver nitrate is indicated Home Ventilators Some patients with tracheostomies will require home mechanical ventilation Caregivers may come in to the ED because the ventilator is alarming at home or the patient is requiring higher levels of support or oxygen Understanding the basics of home ventilators is useful in the workup and management of complications The low pressure alarm on the ventilator will sound if two consecutive breaths not reach the pressure limit; this is usually caused by a leak or disconnect The physician should start at the patient and work toward the ventilator, checking for loose connections Finally, the tracheostomy cuff should be evaluated for leaks and the low pressure alarm should be confirmed to be set at the correct setting The high pressure alarm on the ventilator will sound when the pressure in the circuit has increased This can be caused by frequent coughing, tracheostomy tube obstruction, kinks in the tubing, and water in the circuit Because tracheostomy tube obstruction is so common, the tube should be changed or suctioned and the inner cannula of the tracheostomy tube changed as needed Increased oxygen or ventilator requirements suggest an infectious process and appropriate testing should be obtained, including a chest radiograph and tracheal secretion Gram stain and cultures Hospital admission is often indicated for more aggressive treatment If a patient with a tracheostomy tube and home ventilator is stable to be discharged from the ED, it must be confirmed with the caregivers that they have adequate battery life and oxygen for the drive home CEREBROSPINAL FLUID SHUNTS Background CSF shunt placement is the most common neurosurgical procedure performed in children More than 4,400 CSF shunts were placed in 2003; CSF shunt–related problems accounted for almost 15,000 hospital admissions and almost $300 million in charges for shunt malfunctions CSF shunts are placed to divert CSF from the brain to another area of the body, most commonly the peritoneal cavity The clinician evaluating a child with a CSF shunt should be aware of associated complications such as infection, obstruction, and overdrainage, because certain complications can be disastrous if unrecognized and untreated However, children with CSF shunts may often exhibit symptoms of their chronic illnesses that are unrelated to shunt malfunction Pathophysiology CSF is an ultrafiltrate of plasma produced at a rate of 500 mL/day in a 70-kg adult and proportionally less in children and infants The fluid is mainly produced by the choroid plexus and various extrachoroidal sites within the brain CSF travels from the lateral ventricles into the third ventricle through the foramen of Monro and then again through the aqueduct of Sylvius to the fourth ventricle The CSF then enters the subarachnoid space via the foramina of Luschka and Magendie and travels through the brain and spinal canal CSF is reabsorbed and enters the venous system through the “one-way valves” of arachnoid villi that penetrate the dura Hydrocephalus can result from oversecretion, impaired absorption, or blockage of CSF pathways Oversecretion can occur in some choroid plexus tumors Impaired absorption can occur as a result of increased CSF protein, often a result of perinatal hemorrhage or meningitis or less commonly etiologies such as subarachnoid hemorrhage, or Guillain–Barré syndrome Severe congestive heart failure or any other condition that raises venous pressure may impair CSF absorption as well Impaired absorption is the cause of communicating hydrocephalus, in which flow from the lateral ventricles to the foramina of Luschka and Magendie is not obstructed Blockage of CSF pathways , or obstructive hydrocephalus, is the most common cause of hydrocephalus in children This is often located at the narrow aqueduct of Sylvius proximal to the fourth ventricle and is referred to commonly as aqueductal stenosis Conditions that can cause obstruction are intraventricular bleeding or scarring, tumors, or congenital malformations Dandy–Walker cysts cause obstruction of the foramina of Luschka and Magendie and therefore may result in enlargement of all four ventricles Equipment Different types of CSF shunts vary mostly by the location of the distal tubing and the type of reservoir or valve system The choice of CSF shunt type and the method of placement (endoscopically or nonendoscopically) depend on the individual patient’s anatomy and cause of hydrocephalus and the experiences and preferences of the neurosurgeon performing the procedure Commonly, the patient or caregiver knows the location and type of shunt and is able to provide details regarding prior shunt placement and problems Palpation of the hardware and plain radiographs may be used to acquire more information regarding the specific location of the shunt components Most CSF shunts have the following components: (1) proximal shunt tubing, (2) reservoir system, and (3) distal shunt tubing ( Fig 135.3 ) Occasionally, the system will not contain a reservoir and instead will have a one-way valve The proximal shunt tubing has a fenestrated tip that is usually located in the ventricle but may also be located inside a communicating cyst or in the lumbar subarachnoid space This tip allows free passage of CSF into the shunt system unless it becomes occluded More than one proximal catheter may be present if multiple, noncommunicating areas of the brain require shunting The reservoir system consists of one or two “domes” or “bubbles.” Reservoirs may be placed directly over or slightly distal to the burr hole This information is crucial when emergent access to the burr hole is needed The distal shunt tubing leads from the reservoir unit to a part of the body that can accept the drained CSF, usually the peritoneum The distal tubing may also be located in the vascular system or pleural cavity Ventricular–atrial shunts are less commonly inserted because of the serious infectious complications that have occurred with these types of shunts, but may be necessary due to severe scarring in the peritoneum All modern shunt tubing is made of 1/8-in diameter Silastic elastomer, which causes minimal omental reaction and is resistant to cracking FIGURE 135.3 Diagram of typical ventriculoperitoneal shunt CSF shunt systems contain a one-way valve to prevent backflow of CSF into the ventricles These valves are designed to operate at high, medium, or low pressure Externally programmable valves, which can vary the opening pressure setting, are also available An antisiphon device may be inserted into the distal portion of the system to prevent overdrainage of CSF and concomitant lowpressure complications Clinical Findings/Management Mechanical Malfunction Malfunction of a CSF shunt can be caused by the obstruction of the catheter lumen or disconnection of the various components The proximal catheter lumen