Emergency Management of the Technology-Assisted Child
Emergency Management of the Technology-Assisted Child
Introduction
The acute presentation of the technology-assisted child in the emergency department (ED) setting is a dreaded situation. These children often have numerous ongoing chronic medical conditions, and their lives are assisted by adjuncts that aid feeding, breathing, administration of medication, and cerebrospinal fluid (CSF) drainage. When these devices malfunction, they can put children at risk of serious medical and surgical problems. Often, the patient has associated developmental delay, making an appreciation of the child's baseline functioning challenging. In these cases, reliance on the caregiver's history is recommended. These children are equally, if not more, susceptible to common illnesses such as viral upper respiratory infections (URIs).1 Furthermore, serious adjunct malfunctions can mimic relatively benign illnesses.1,2 This review addresses some of the challenges faced by emergency physicians when encountering adjunct malfunctions in the technology-assisted child.
Emergency Management of CSF Shunt Malfunction
Case Study. A 17-year-old boy with severe developmental delay presents with apparent headaches, vomiting, and fever. He had URI symptoms for the past week. For 24 hours, he has suffered 3-5 bouts of non-bloody, non-bilious vomiting unrelated to gastrostomy feeds. On the day of presentation, he had a temperature of 100.2°F. There is no history of trauma.
At baseline, his communicative skills are limited to facial expressions and incoherent verbal sounds, but usually he is smiling and interactive.
His past medical history includes a ventriculo-peritoneal (VP) shunt inserted at 1 year of age for hydrocephalus. He has had three revisions the past 11 years, with the most recent one four months ago. He has had a gastrostomy tube since age 5 and is incontinent of stool and urine.
His vital signs: temperature 101°F, heart rate 109 bpm, respiratory rate 20 breaths/min, and blood pressure 130/97 mmHg, oxygen saturation of 96% on room air.
The examination reveals a palpable VP shunt running down his neck. A reservoir system is palpated just above the right aspect of the occiput. The dome is firm.
His neurological examination is unchanged from the past.
The shunt series is unremarkable; the head CT shows increased ventricles compared to previous scans. The neurosurgeons perform a shunt manometry, which indicates sluggish pressures. The patient is scheduled for revision of his shunt.
Overview. More than 33,000 shunt procedures are performed annually.3,4 The shunt is placed to relieve increased cerebrospinal fluid pressure caused by overproduction, reduced absorption, or anatomical obstruction of the draining system. The shunt redirects CSF to an alternative cavity (usually the peritoneum) where it can be safely reabsorbed.1 Other cavities are less commonly used due to an increased risk of infection.5
The apparatus commonly consists of three components: the proximal shunt tubing, the reservoir, and the distal shunt tubing. (See Figure 1.)
Epidemiology. Prospective trials such as the Shunt Design Trial and the Endoscopic Shunt Insertion Trial have found up to 40% incidence of malfunction in the first year and 50% incidence by the second year following initial shunt placement.6,7 This incidence increases to 80% over 10-12 years following insertion.5-7 The literature describes that overall shunt survival at four years can be as low at 41%.7
Pathophysiology. The causes of shunt malfunction are summarized in Table 1.
As the patient grows, there is increased tension and degradation on a system designed for a certain size and age. Therefore, there is a greater likelihood of disconnection or fracture of the apparatus. Occasionally, other compartments of CSF, called loculations, may develop that do not communicate with the ventricular catheter and may cause pressure on the surrounding brain. Loculations can be diagnosed by imaging with contrast.8
The drainage system may be too efficient and cause excessive drainage of CSF, both acutely and chronically, as is the case with extra-axial fluid collections and slit ventricle syndrome, respectively.8
Abdominal Causes. Shunt malfunction may arise due to abdominal complications such as ascites.9 Similarly, an abdominal pseudocyst in proximity to the distal peritoneal catheter can enlarge not only enough to reduce drainage but also to cause bowel obstruction. Additionally, the distal portion of a CSF shunt may migrate and cause visceral damage or even perforation.9
Infectious Causes. According to the Shunt Design Trial, 8.1% of shunt failures had an infectious etiology.11 Early shunt infections are due to Staphylococcus epidermidis and S. aureus.1 Late infections may be due to gram negative organisms from the abdomen. However, as explained below, the shunt infection may present very similarly to any other cause of shunt malfunction.
Clinical Features of Shunt Malfunction. Shunt malfunction presents as raised intracranial pressure, namely headaches and vomiting. Drowsiness, decreased level of consciousness, and irritability also show positive correlation with shunt malfunction.3 A summary of clinical features and signs is listed in Table 2.
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The predictive ability of experienced parents to determine a shunt malfunction can have a sensitivity and specificity as high as 88.9% and 62.2%, respectively.12 Kim et al. recommend that a full work-up of a shunt malfunction be considered when parents or caregivers who have experienced at least three revisions are at least 66% confident that their child is experiencing a shunt malfunction.12
Examination. The emergency physician should perform a thorough assessment, focusing on the neurological examination as well as palpation of the abdomen in the case of a VP shunt. It is important to follow the shunt from its proximal to distal end looking for overlying skin changes such as swelling, erythema, and signs of tissue breakdown.3 There is varying evidence as to whether effective pumping of the shunt reservoir helps ascertain whether there is a proximal or distal malfunction.1,13 With single bubbles or domes, a tense, non-depressible dome may indicate a distal problem, whereas a dome that sluggishly refills after pressing may indicate a proximal malfunction.1 With a two-domed configuration reservoir, the more distal dome should be pressed after the proximal dome. A proximal malfunction may be identified with poor refill of the proximal dome, while resistance to pressure on the distal dome may indicate a distal malfunction.1 The value of this test is questionable, with a positive predictive value of 21% and a negative predictive value of 78%.1,13
Diagnostic Studies. Patients similar to the one described should have a shunt series and a cranial CT. The shunt series consists of a set of X-rays (skull, neck, chest, and abdomen) that track the progression of the shunt throughout its entire course to assess shunt integrity. However, there is now controversy about both of these modalities.
Retrospective studies have shown that the sensitivity of the shunt series can be as low as 20%, with a negative predictive value of 22%.8 Furthermore, CSF shunt malfunction can and often will present without ventriculomegaly.14 Estimates of CT sensitivity have ranged from 64-94%.8,15,16
Despite the low sensitivity of the shunt series, studies have shown that it may aid in diagnosing a malfunction that was missed with the CT scan alone.3,16 Furthermore, when both a shunt series and CT scan are performed, the combined sensitivity is 88% for detecting malfunctions.16
The present consensus is to obtain a shunt series and a head CT and neurosurgical consultation even if imaging is unremarkable. Shunt infections have been shown to be associated with an elevated C reactive protein (CRP), as well as a leucocytosis with neutrophil counts exceeding 10%.17,18
Management. Shunt aspiration or tap should be performed only by a neurosurgeon. Poor flow can be defined as absence or return of CSF after applying up to 2-3 mL of negative pressure using the 3 mL syringe and has been shown to correlate with a proximal obstruction of the hardware.19 Normal pressure on manometry is 5-10 cm H2O, and pressures exceeding 20-25 cm H2O have been shown to correlate with a distal malfunction.19 In the event of acute severe obstruction, shunt aspiration may be used to relieve symptoms in conjunction with acetazolamide, dexamethasone administration, and ensuring hyperventilation.1 Life-threatening obstruction may be managed with neurosurgical burr hole puncture.1
It is recommended that aspiration for diagnostic purposes should be restricted to specific circumstances, e.g., when there is suspicion of a shunt infection in spite of normal imaging and there is a non-communicating hydrocephalus or if an anatomical lumbar abnormality is hindering a lumbar puncture (e.g., in myelodysplastic patients).20 In all other cases, less invasive measures such as the clinical presentation and imaging should be sufficient to make a diagnosis of a malfunction.2,20
Shunt infections should be managed with appropriate antibiotic coverage such as vancomycin and a cephalosporin.3
Pearls and Pitfalls of Emergency CSF Shunt Care
Shunt malfunction signs and symptoms can be nonspecific.
The experienced parent's or caregiver's account may be invaluable in diagnosing a potential malfunction.
Routine management for a shunt malfunction in the ED includes a CT head, shunt series, and neurosurgical consultation.
Shunt aspiration is not a routine diagnostic investigation.
Emergency Tracheostomy Care
Case Presentation. An 18-month-old girl with chronic lung disease presents to the ED with acute respiratory distress. She has a tracheostomy, and requires home oxygen and constant respiratory care. For the past few hours, she has been desaturating into the 50s despite physiotherapy, suctioning, and increased oxygen.
Her parents explain that she was a premature infant who had a prolonged course in the neonatal intensive care unit (NICU). Weaning her off ventilation has been difficult. She subsequently underwent a tracheostomy and has since improved considerably. She was discharged approximately 7 months ago.
Four days ago, she developed increased nasal and tracheostomy discharge that turned thick yellow-green. Her breathing has become more labored despite saline drops, suctioning, and physiotherapy. Her oxygen requirement increased from 1-5 L over 24 hours.
Physical Examination. Vitals: Heart rate 120 bpm, respiratory rate 66, blood pressure 110/70 mmHg. Oxygen saturation is 90% on 15 L of oxygen. She appears in considerable respiratory distress. Nasal and oral secretions are thick. She has a 4.0 uncuffed bivona tracheostomy tube. The stoma is erythematous. Her chest exam reveals coarse upper airway breath sounds.
A chest X-ray shows that the tracheostomy tube is more than 2 cm above the carina and there is patchy infiltrate in the right mid and left upper chest.
During examination, her saturations drop to the 50s and she becomes cyanotic. There are copious secretions, and advancing the suction catheter is challenging. The decision is made to change the tracheostomy tube. High-flow oxygen is administered, the ties of her old tube are undone, and her tube is successfully exchanged with a 3.5 uncuffed bivona. On a repeat chest X-ray, the tube appears to be within the trachea, 2 cm above the carina.
She is treated with IV ampicillin-sulbactam and admitted.
Overview. The tracheostomy tube has become a life-saving adjunct in children who are at risk for devastating airway compromise. The majority (65%) of these children with chronic respiratory insufficiency (CRI) have on-going pulmonary co-morbidities such as a congenital deformity of the airways or, as in the case above, acquired lung disease secondary to gastroesophageal reflux.1 The tracheostomy tube also is used when there is neuromuscular compromise of ventilation, as in the case of muscular dystrophy, spinal cord injuries, as well as disorders that affect the central respiratory drive such as intracerebral space occupying lesions (5%).1,22
Most pediatric tracheostomy-related complications occur outside the hospital setting. Thus, the emergency physician should be prepared to change a tube in the event of airway compromise.
Tube Composition. Three types of tubes are described in Table 3. Plastic tubes tend to be used more commonly in children than metal composite tubes.1,23,24 PVC tubes are used in older children and have the characteristic of conforming to the trachea shape while remaining rigid. However, silicone tubes (which tend to be used in younger children) may be substituted to attain a better fit.23 The PVC tubes are at risk of stiffening and fracture with repeated use and cleaning.24
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Tracheostomy tubes may be cuffed or fenestrated. Cuffed tubes are used rarely in pediatric patients, but they may be employed to prevent aspiration, or to provide high airway pressures or support for children who depend on nocturnal ventilation.23,24 Cuffed tubes should always be deflated prior to removal. When re-inflating the tube, the physician must be vigilant about maintaining the cuff pressure and volume so that it remains at "just seal"' or "minimal occlusion" and does not impinge on capillary perfusion of the tracheal mucosa.24
Fenestrated tubes have a limited use in pediatrics. They aid phonation in children with speaking valves. If these tubes fit poorly, they can considerably increase airway resistance. There also is evidence to suggest that fenestrated tubes may be associated with the formation of granulation tissue.23,25 (See Figure 2.)
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Tracheostomy Adjuncts. Passive Humidifiers/Heat Moisture Exchangers. Tracheostomy tubes deliver cold, dry air to the lungs because they bypass the nose and the mouth. Passive humidifiers are an essential portion of the apparatus to capture heat and moisture from expiration and add it to inspired air, ensuring decreased irritation and friability of the tracheal mucosa.22-24 However, humidifiers do not function with speaking valves unless specifically designed to do so.24
Speaking Valves. These valves provide expiration around the tube and through fenestrations. They permit phonation and promote effective coughing and positive end expiratory pressure, essential in reducing atelectasis. Speaking valves may result in increased breathing efforts.24
Swivel. This device allows for flexibility of neck motion, which is extremely useful in a moving child. It also provides additional length, ensuring that the tube is away from the soft tissues of the neck.1
Tracheostomy Tube Parameters. Choosing the appropriate diameter, length, and curvature of the tube is important when changing a tracheostomy because these factors will determine the effectiveness of the new airway. The following guidelines are adapted from the American Thoracic Society.24
Length. The tube should extend 2 cm beyond the stoma but no further than 1-2 cm to the carina. It may be advantageous to use a neonatal length tube in children younger than 1 year and a pediatric length tube in older children.23
Diameter. The internal diameter determines the size and usually is printed on the tube. This measurement is universal among manufacturers; however, the outer diameter may vary. Although there are no set parameters, the tracheostomy diameter should be small enough to avoid internal trauma yet large enough to ensure appropriate translaryngeal flow and reduce airway resistance.23,24 In common practice, the outer diameter should not exceed two-thirds of the diameter of the trachea, especially when using a speaking valve.24
Adapter. All non-metal tubes should have a 15 mm universal adapter to allow bag ventilation in an emergency.
Complications. Obstruction. As with all indwelling tubular devices, obstruction is one of the most common causes of malfunction and may result in acute asphyxiation. In children older than 1 year, the incidence can be as high as 14% and is even higher in premature babies and newborns (72%).26 This is thought to be due to relatively smaller sized tubes used in infants.1 Furthermore, infants often are being treated for neonatal respiratory complications such as chronic lung disease or bronchopulmonary dysplasia, which are associated with copious secretions.
For children who are more prone to occlusion, caregivers should be advised to perform more frequent tube care as a preventive measure upon discharge.
Decannulation. Tracheostomy decannulation or dislodgment may occur at any point in the lifespan of the tube, but the incidence tends to be increased in older ventilated children, possibly due to augmented external tension and torque of the tubing.24,27 Decannulation may present insidiously; the tube may go through the stoma site but may not be within the trachea itself.
Obstruction and decannulation are life-threatening complications.28 Any child with a tracheostomy who presents with severe respiratory distress, fatigue, or unresponsiveness (as in the case above) should have equipment failure ruled out first. High-flow humidified oxygen is started, followed by evaluation of tracheal lumen patency and tube position.28 The emergency physician should be prepared to change the tubes if needed.
Infection. Another common complication of an indwelling device is infection, especially if the device is in place chronically. Tracheostomy infections commonly present with copious, possibly odorous, yellow-green secretions with or without associated systemic signs of infection and respiratory compromise.1,22 A tracheostomy infection may even progress to a tracheitis (especially in light of leucocytosis documented in tracheal secretions) or pneumonia (with focal clinical or radiographic changes). The patient also may have peristomal cellulitis.1
Since common pathogens are gram positive, gram negative, and anaerobic bacteria that naturally colonize a tracheostomy tube, it may be difficult to differentiate between an infection and colonization.
The management of a tracheostomy infection consists of ensuring airway patency, and adequate work of breathing (infectious secretions can cause obstruction), and sending secretions for gram stain, culture, and rapid viral detection assay. Depending on their oxygen requirement, these children may go home on a course of oral antibiotics or may need to be admitted with supplementary oxygen therapy, IV antibiotics, and frequent suctioning.1
Bleeding and Granulomas. The mucosa adjacent to the tracheostomy site, the tracheostomy tip, and cuff is prone to pressure and irritation. With poor humidification, this mucosa becomes vulnerable to bleeding and subsequent granuloma formation.22 In the weeks following tracheostomy placement, granulomas may be soft and fragile but may become fibrous over time.24,29,30 Large granulomas may obstruct the lumen and increase the likelihood of bleeding. Depending on their size and risk of obstruction, granulomas may need to be surgically excised or cauterized with silver nitrate.1,24
Chronic erosion of the anterior tracheal mucosa leads to the risk of communication with the innominate artery, resulting in massive, life-threatening bleeding. In these circumstances, the physician must treat with humidified oxygen, suction, and intravenous fluids to replace losses and refrain from removing the tube in the unstable patient, as the airway may be lost.1,24 Instead, apply pressure to the bleeding site, if it can be visualized, or inflate the cuff to provide a tamponade effect until definitive treatment is available. Any bleed ultimately will need to be investigated by bronchoscopy.22,24
Tracheo-esophageal Fistula. Similarly, erosion of the posterior tracheal wall may result in communication with the esophagus. Subsequent contamination of the airways with esophageal contents can be life-threatening.24
Other Complications. Suprastomal collapse may arise when local inflammation causes chondritis and weakening of the cartilages superior to the site. This complication of a prolonged tracheostomy can delay or even prevent removal of the tracheostomy tube.24,31 Prolonged irritation of the trachea or placement after emergent surgery also presents a risk of stenosis, which can complicate recannulation.
The most common complication of decannulation is a tracheocutaneous fistula, which occurs in up to 40% of children.24 It is important to be vigilant for an underlying airway obstruction in these circumstances. If the fistula persists, surgical closure may be necessary.24
Pearls and Pitfalls of Emergency Tracheostomy Care
The tracheostomy tube should extend 2 cm beyond the stoma and no further than 1-2 cm to the carina.
Obstruction is more common in young infants; decannulation is more common in older children.
In the event of a life-threatening bleed from a tracheostomy site, avoid removing the tube until the patient is stabilized and instead inflate the cuff if there is one present.
Emergency Management of Enteral Feeding Tube Complications
Case Study. A 2-year-old boy presents 30 minutes after his G-tube dislodged. This patient has poorly controlled cystic fibrosis and failure to thrive secondary to neglect. Six weeks ago, he had a percutaneous endoscopic gastrostomy (PEG) placed to ensure supplemental nutrition. This evening, he pulled out his Button G-tube with its balloon inflated. His guardian describes minimal initial bleeding at the stoma site. He complains of localized abdominal tenderness.
Vital signs are normal. There is some mild erythema at the gastrostomy site but no active bleeding. His abdomen is benign, and there are active bowel sounds.
The decision is made to insert a new G-tube.The new G-tube balloon is inflated and deflated with saline to check integrity. The stoma site is cleaned, and drapes are placed. Both the tube and stoma are lubricated with a water-soluble lubricant and topical lidocaine. The G-tube is passed through the opening and the balloon is inflated. Formula is aspirated. Bowel sounds are heard after injection of 10-15 mL of air via the G tube.
Indications for a Gastrostomy Tube. Since the 1980s, gastrostomy tubes have functioned as essential feeding adjuncts for children who are unable to provide themselves with appropriate oral nourishment or have poorly coordinated swallowing, placing them at risk of aspiration.32-34 The indications for a gastrostomy tube include craniofacial anomalies, esophageal atresia, caustic or thermal erosion of the esophagus, neurological deficits that affect oropharyngeal muscle tone and coordination (e.g. muscular dystrophy, myasthenia gravis), malabsorption syndromes, and chronic gastroesophageal reflux.1 In patients with obstruction, the PEG also may act as a decompressing device.32
When there is delayed gastric emptying, high risk of aspiration, or severe gastroesophageal reflux, a jejunostomy tube may be preferred. A gastro-jejunal tube enters at the gastrostomy site and continues through the stomach directly into the small intestine, allowing decompression of the stomach. It is usually placed with interventional radiological assistance.1
Anatomy and Pathophysiology. The gastrostomy provides communication through the skin, subcutaneous tissue, peritoneum, and anterior or anteriolateral wall of the stomach. A PEG (percutaneous endoscopic gastrostomy) is the most popular means of creating the stoma. Once the tube is passed, it is secured with a purse string suture that fixes the stomach to the parietal peritoneal lining of the abdominal wall. Over time, a fistulous tract forms and the adherence between the stomach and the internal abdominal wall becomes permanent.33,34(See Figure 3.)
Types of Gastrostomy Tubes. The composition of tubes includes rubber, silicone, and polyurethane. There are varying tube lengths and connectors as well as methods by which tubes are anchored within the lumen of the stomach. The emergency physician should be aware of three main types of gastrostomy tubes. (See Table 4.)
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Gastro-jejunostomy tubes usually are small diameter (8 F) and have a mercury tip that enables placement under fluoroscopy.1
Gastrostomy Tube Complications. Dislodgment. dislodgment is common, especially in the first 5 months after surgery.35 Dislodgment may be due to acute trauma, tension on the external tubing, as well as deflation or rupture of an eroded balloon tip.30 Clinically, the tube may extrude and there may be bleeding or leakage of gastric contents at the stoma site. The site may appear closed, and patency may be confirmed only using a lubricated cotton-tipped applicator.33 Management in the emergency department depends on how long the tube has been out of the stoma and the how recently the stoma was formed.
The definitive treatment of dislodgment is to replace with the same tube type and size as soon as possible to prevent stoma narrowing. Infusion of IV fluids also would be an appropriate management option while the G-tube is out. A Foley catheter (with inflated balloon) may be placed temporarily to maintain stoma patency when the gastrostomy is long term and the dislodgment is recent until the proper tubing is identified or available.1,34 Prior to any tube replacement, it is crucial to check the anchoring mechanism, e.g., by inflating the balloon or advancing a stylet or obturator to fully distend the distal tip of the tube.33
If hours have elapsed since dislodgment, the stoma may have begun to constrict.33 In such cases, dilate the stoma by introducing increasing sizes of Foley catheters and then use a smaller replacement gastrostomy tube.1,34
In the perioperative phase (up to 3 months since initial stoma formation), the management of tube dislodgment must be approached with extreme caution, as the stomach may not have fully adhered to the anterior abdominal wall and is at risk of separation.34 Placement of a Foley catheter or replacement G-tube may disrupt the fistulous tract and create a false lumen (especially if sufficient force is applied). Administration of feedings in these circumstances could result in a life-threatening pneumoperitoneum or chemical and bacterial peritonitis.36 Obtain a pediatric surgery or pediatric gastroenterology consult prior to any replacement attempt.
Likewise, a dislodged jejunal tube should be replaced only by the subspecialists responsible for its insertion.
Obstruction. All indwelling tubes pose a risk of obstruction, and gastrostomy tubes are no exception. Formulas such as Ensure, Pulmocare, and Osmolite as well as medications such as anti-seizure preparations can solidify when in contact with gastric contents, resulting in tube blockage.33,37 Obstruction also may arise from twisting or kinking of the apparatus.
When the tube appears to be obstructed, flush with warm water. There is no definitive evidence that carbonated sodas are more effective than water at removing G-tube obstructions.38 A stylet never should be used to clear an obstruction as this may cause a blind perforation of the tubing beneath the skin.1 If the G-tube remains obstructed despite these attempts, it should be repositioned or replaced (see prior section). Caregivers should flush the tube after each feeding.
Leaking. It is important to establish whether leaking is occurring from the lumen of the tube or from the stoma site and whether the fluid is purulent, blood-stained, or indicative of formula.
A peristomal abscess or cellulitis should be ruled out immediately if the drainage is purulent.1 However, if formula or gastric contents are leaking from the stoma, this may indicate stomal dilation or that the G-tube diameter is not large enough to ensure a tight fit. In these circumstances, it might be beneficial to remove the G-tube and allow the stoma to constrict for a short period (with monitoring) before replacing it.1 Alternatively, the physician may choose to pass a larger-diameter G-tube.1
Fluid leak from the tube itself may arise due to poor positioning, inadequate anchoring by an underinflated balloon, deterioration of the G-tube material leading to splitting, or, in the case of a leaking Button, a malfunction of the valves within the tube.36 In these cases, the tube may need to be replaced if simple repositioning maneuvers are unsuccessful.
Other Complications. Reflux. G-tube placement may be counterproductive in the treatment of reflux, and patients can present with increased bouts of vomiting and heartburn shortly after initial placement. Continuous feeds may provide symptomatic relief, but if symptoms persist, a Nissen fundoplication ultimately may be required.1,37
Gastric Ulceration. The tube or anchor may cause abrasion to the gastric lining, resulting in symptoms ranging from abdominal pain to hematemesis, hematochezia, and melena. If saline lavage yields non-bloody fluid from the G-tube, administration of proton pump inhibitors, H2 blockers, antacids, IV fluid rehydration, and G-tube replacement are appropriate mucosal protective measures prior to an endoscopy.1
Stomal Complications. As with tracheostomies, the stoma site is vulnerable to irritation, granulation, and infection from bacteria and fungi, which ultimately could lead to erosions and breakdown of the surrounding skin. The ED physician should be vigilant for signs of cellulitis or abscess. Appropriate stoma care and hygiene, namely preventing prolonged skin contact with G-tube feeds as well as keeping the site clean and dry, should be promoted.
Pearls and Pitfalls of Emergency Gastrostomy Tube Care
Avoid replacing a dislodged G-tube during the perioperative phase (up to 3 months since initial stoma formation) without seeking surgical or pediatric GI advice.
Following tube dislodgment, a stoma may be kept patent or widened with Foley catheters.
G-tube obstructions may be cleared with warm water infusion. They should not be cleared using a stylet.
Emergency Management of Indwelling Venous Access Devices
Case Report. A 4-month-old girl presents with suspected occlusion of her central venous catheter. She had an extensive small bowel resection for mid-gut volvulus at 26 days of life. A Broviac line was inserted through her right external jugular vein. She has been receiving home TPN. This morning her mother was not able to aspirate or advance fluids through the line.
Vital signs: temperature 99.3°F, pulse 120 bpm, BP 87/50 mmHg, and respiratory rate 35 breaths/minute.
She has a Broviac in the right external jugular vein. There is no drainage of blood or fluid, and no erythema or erosion of the site of insertion.
Based on her history, her Broviac is clamped and a chest X-ray shows appropriate position of the line. Under sterile technique, the ED nurse removes the Broviac cap, cleans the catheter hub with chlorhexidine and attempts to flush 3 mL of normal saline. Unfortunately, this is unsuccessful despite raising her arms and positioning her in the Trendelenberg position. The line is flushed with 3 mL of 70% ethanol and observed for 1 hour. A repeat flush of 5 mL normal saline is successful. Prior to re-applying a dressing, 3 mL of 10 U/mL heparin is infused, and the cap is replaced.
Overview and Indications for the Use of Indwelling Venous Access Devices. Central venous catheters (CVCs) are used for chemotherapeutic agents, or antibiotic chemoprophylaxis for chronic infection management (e.g. in the case of osteomyeleitis).1,39 The CVC also is an ideal method of supplying total parenteral nutrition to children with severely compromised digestive systems (as in the case of bowel resection).1,39
CVC may provide a stable permanent or semi-permanent access to the vena cava so that preparations that otherwise would damage peripheral veins can be given. Unfortunately, the advantages of having central venous access are counterbalanced by the potential risks of failure. Common causes of malfunction include occlusion, embolisms, disruption or breakdown of the catheter, displacement, and infection.1
Anatomy and Equipment. There are several types of CVCs, and their use depends on the patient's age, level of development, the underlying problems, patient preference, as well as the potential risks of the device.40 They are divided into two subclasses: partially implantable ("tunneled") venous catheters and totally implantable venous access devices.
Partially Implantable Venous Devices. These are the earliest catheters used, and they include Broviac, Hickman, Leonard, Raaf, Hermed, Groshong, and Corcath central lines.1,39 Like totally implantable venous devices, the catheter tip lies at the junction between the superior vena cava and the right atrium; however, partially implantable venous devices enter through the external jugular, subclavian, or brachiocephalic veins.39 They also differ from totally implanted devices in that the proximal end tunnels for a few centimeters beneath the skin away from the venous entry site before exiting at the chest and terminating with a female Luer lock tip at the end. These tubes are anchored in place indirectly by a Dacron® cuff, which stimulates the formation of a fibrin sheath within 2 weeks of insertion. The cuff also acts as an effective antimicrobial barrier.39,41
Totally Implantable Venous Devices. These adjuncts are newer devices and commonly are manufactured by Infusaport and Port-A-Cath.1,39,41 Unlike partially implantable venous devices, they lie exclusively under the skin. The proximal end of the tube is a subcutaneous reservoir chamber that has a self-sealing cap, allowing for repeated access by needles. The tubing of these devices normally enters the venous system via the subclavian vein but also may enter via the internal jugular to reach the superior vena cava-right atrium junction.1,39,41 (See Figure 4.)
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Complications. Catheter Occlusion. Occlusion is common. Sixty percent of all catheter occlusions arise due to fibrin deposition or obstruction by a clot (a thrombotic occlusion).42,43 Non-thrombotic causes include collection, precipitation, or crystallization of drugs, minerals, and TPN components. Catheter occlusion also may arise due to extraluminal (mechanical) causes, such as kinking of the tubing, tight suturing, catheter migration, malposition, or anatomical pinching off at the clavicle or first rib.43
Assessment for Mechanical Obstruction (adapted from Fein et al, Fuchs & Kerner et al.1,39,43)
1. Assess the catheter system to check for external compressions from clamps, sutures, or malpositioning.
2. Using 3-5 mL of normal saline, flush and aspirate the catheter with a 5-10 mL syringe. Special care must be taken not to infuse by force, as this might cause ballooning of the catheter, rupture, or even may force an intraluminal obstruction distally.
3. Repeat aspiration and flushing after postural changes such as raising the ipsilateral arm or shrugging the shoulders to check for kinking. Pinch-off syndrome should be considered as a possibility if blood can be aspirated only when the patient's arm ipsilateral to the catheter is raised parallel to the shoulder. This may cause migration of the line and puts the catheter at risk of rupture and embolism.43
4. Repeat aspiration when asking the patient to cough or perform the Valsalva maneuver. Additionally, the patient may be placed in reverse Trendelenberg position. These tactics may help to dislodge an obstruction or may indicate malposition.
5. Obtain a history about what has been infused into the catheter.
6. Examine the patient for erythema, edema, pain, or dilation of vessels.
7. With occlusion, plain films must be obtained to ensure appropriate position.
8. If there is risk of pinch-off syndrome, the catheter may need to be replaced using fluoroscopy.
Management of Thrombotic Occlusions. Once a mechanical obstruction has been excluded, a thrombotic occlusion should be considered. These may occur gradually or acutely. They consist of four types: a fibrin tail or flap, a fibrin sheath or sleeve, an intraluminal obstruction, and a mural thrombus.43 The clinician must approach these cases with great caution, as there is a risk that clots could embolize distally. It is important to be vigilant for the clinical signs of embolic disease (similar to signs and symptoms of air embolism, see below) or even occlusion of the superior vena cava.
Previously, management included the use of urokinase infusions to help break down a thrombotic occlusion. However, recent literature suggests alteplase infusions are highly effective in restoring catheter function with minimal adverse reactions.43-46 One protocol advises instilling 2 mg/2 mL alteplase in patients who weigh more than 30 kg. In patients less than 30 kg, a dose large enough to fill 110% of the internal catheter volume should be instilled. The dosage may be repeated if the catheter cannot be aspirated both immediately and after 2 hours of observation.43
Management of Non-Thrombotic Occlusion. (See Table 5.)
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Catheter Breakage. Although this is relatively uncommon, catheters may be vulnerable to breakage and rupture.40 Torque and tension of the apparatus or minor trauma during activity may contribute. Even maintenance procedures, e.g., removing the dressing with scissors or aspirating with a needle, may inadvertently create a puncture site that could evolve into a rupture.1 Breakage is more likely to occur in partially implanted devices due to increased exposure to the external environment.
Clinically, if there is any leakage of blood or fluid, a breakage should be suspected and the catheter (if partially implanted) should be immediately clamped proximal to the damaged segment to prevent further leakage or introduction of an air embolus.1,39
Partially implanted devices can be repaired with kits that have connectors compatible with a smoothly cut end of the catheter. However, totally implanted devices need radiographic imaging to ascertain tube integrity.39 Ultimately, a consult may be necessary if the catheter cannot be repaired.
Catheter Displacement. This complication may arise from the causes mentioned for breakage, a loose partially implanted device or with the Dacron® cuff visible above the skin. There may be bleeding at the site of insertion. In these cases, the catheter should be clamped and its position confirmed with a chest x-ray or even a contrast study if free-flowing blood cannot be aspirated. Totally implanted devices are less vulnerable and would need significant chest trauma to incur possible displacement.1 As with a breakage, contacting the pediatric surgeons is justified.
Air Embolism. Although rare, the incidence of air embolism is highest with venous access devices during the initial positioning or with maintenance of the catheter.47,48
The ED physician should be suspicious of an air embolism in any patient with a central line who presents with dyspnea, tachypnea, shortness of breath, lightheadedness, chest pain, tachycardia, and hypotension.39,47 Suspicion is even higher if there is a history of tubing that has remained unclamped.1
On examination, it may be possible to hear a mill-wheel murmur representing a large air bolus trapped within the right ventricle.47 Paradoxical embolus may occur in children with endocardial cushion defect, resulting in neurological signs such as seizures, focal deficits, and coma.47
Immediately provide 100% oxygen, clamp the catheter, and perform Durant's maneuver (placing the patient on the left side in Trendelenberg) to ensure that air in the right ventricle can collect and move away from the right ventricular outflow tract. If the embolus is large and cannot be aspirated out from the line, it would be appropriate to consult the cardiothoracic surgeons.47
Catheter Infection. As with all indwelling devices, central venous catheters potentially can create a porthole for pathogens to enter the body. This risk of infection is further amplified when suboptimal sterile technique is used during initial insertion and subsequent procedures, and when the child is already immunocompromised.
The emergency physician should be suspicious of a line infection in any child with a CVC who presents with a fever. Infection is the most common complication of central venous catheters.49,50 Clinically these patients may have erythema, edema, tenderness along the catheter site, and purulent drainage. Be sure to remove all dressings when examining the patient.
The most common bacterial pathogens are skin commensals such as S. epidermidis, S. aureus, and Viridans streptococci. However, with hyperalimentation there is always the added risk of gram-negative organisms such as Pseudomonas aeruginosa, Klebsiella pneumonia, and E. coli. Concurrent fungal infections can develop. Partially implantable catheter devices have an increased risk of infection compared to totally implantable devices. In the first 100 days following insertion, there also is risk of a surrounding soft-tissue or pocket infection.51
Obtain blood cultures from all catheter lumens as well as peripherally. Purulent drainage and discharge from the site should be cultured. Empirical antibiotic therapy with vancomycin and a third- or fourth-generation cephalosporin is started until cultures return. Apply topical antibiotic cream for possible skin infections.1 In cases of a severe pocket infection, the catheter may need to be removed.52
Pearls and Pitfalls of the Emergency Management of Indwelling Venous Access Devices
Thrombotic occlusions are the most common complication of CVCs and can be managed with alteplase after ensuring there is no mechanical obstruction.
Non-thrombotic occlusion management depends on which formulas or medications have been infused prior to the obstruction.
If there is evidence of catheter displacement or breakage, the catheter should be clamped proximal to the damaged segment if possible.
Air embolism should be suspected in a patient with a CVC who presents with dyspnea and tachypnea with an associated history of tubing that has remained unclamped.
Summary
Technology has significantly changed the lives of many children. However, these tubes and catheters cannot replicate the body's natural vessels and conduits. They are more prone to malfunction secondary to obstruction, displacement, and infection. The ED physician should know the location of equipment and understand the management of complications seen in the technology-assisted child.
References
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The acute presentation of the technology-assisted child in the emergency department (ED) setting is a dreaded situation. These children often have numerous ongoing chronic medical conditions, and their lives are assisted by adjuncts that aid feeding, breathing, administration of medication, and cerebrospinal fluid (CSF) drainage. When these devices malfunction, they can put children at risk of serious medical and surgical problems.Subscribe Now for Access
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