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* From the Department of Pediatrics (Drs. Hertzog, Hauser, and Dalton), Division of Pediatric Critical Care Medicine and Pulmonary Medicine, Georgetown University Medical Center, Washington, DC; and the Department of Pediatrics (Dr. Siegel), Division of Pediatric Pulmonary and Critical Care Medicine, Mount Sinai Medical Center, New York, NY.
Correspondence to: James H. Hertzog, MD, Division of Pediatric Critical Care Medicine and Pulmonary Medicine, CCC-5414, Georgetown University Medical Center, 3800 Reservoir Road NW, Washington, DC 20007-2197; e-mail: hertzogj{at}gunet.georgetown.edu
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Key Words: laryngotracheal reconstruction • noninvasive positive-pressure ventilation • pediatric intensive care
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Introduction |
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Noninvasive positive-pressure ventilation (NPPV) by nasal mask is a method of providing mechanical ventilatory support in the absence of tracheal intubation, and it has been employed in adults with both acute and chronic respiratory failure, effectively improving oxygenation and ventilation.3 4 5 6 More recently, the use of NPPV has been reported in pediatric patients.7 8 9 10 11 In addition, NPPV avoids the trauma to the trachea associated with the insertion and maintenance of a tracheal tube. NPPV may therefore serve as a bridge between mechanical ventilation (via a tracheal tube) and spontaneous breathing in patients after LTR, providing airway stenting and ventilatory support while tracheal edema and pulmonary dysfunction dissipate.
In this report, we present the cases of two children with subglottic stenosis treated with LTR who developed respiratory failure following tracheal extubation. Subsequent management included NPPV. In both cases, NPPV facilitated the transition to spontaneous breathing while avoiding tracheal intubation during a period of respiratory insufficiency.
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Case Reports |
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Laryngotracheal reconstruction was performed with anterior and posterior cricoid splits and autogenous rib-cartilage graft placement. The patient was admitted to the PICU postoperatively with a 4.0-mm internal diameter (ID) nasotracheal tube sutured in place. Sedation, analgesia, and neuromuscular blockade were maintained with continuous medication infusions. Intermittent episodes of atelectasis were responsive to chest physiotherapy and transient increases in positive end-expiratory pressure. Intravenous steroids were prescribed on postoperative day 5 to minimize airway edema prior to tracheal extubation. On postoperative day 7, the child returned to the operating room for direct laryngoscopy and bronchoscopy, revealing intact grafts and adequate healing. The patient failed tracheal extubation on postoperative day 8, secondary to a subsequently diagnosed infection with respiratory syncytial virus.
The child's trachea was reintubated, and he received inhaled bronchodilators, IV steroids, sedative and analgesic medications, and intermittent doses of neuromuscular blocking agents. His trachea was extubated on postoperative day 12, but shortly afterward he developed respiratory distress with facial swelling and subcutaneous emphysema. The child's trachea was again intubated, and a chest tube was placed to drain a right-sided pneumothorax. Bronchoscopy on postoperative day 14 revealed wound dehiscence at the inferior aspect of the laryngotracheoplasty graft. A 4.0-mm ID cuffed endotracheal tube was placed for conservative management of the wound dehiscence and associated air leak. IV steroids were discontinued. Supportive therapies were continued through postoperative day 21, when the patient again underwent bronchoscopy, demonstrating no wound dehiscence or granulation tissue.
On postoperative day 22, the child's trachea was again extubated. He received supplemental oxygen via a face mask and nebulized racemic epinephrine. Initially, the child appeared comfortable, but he developed stridor and respiratory distress within an hour, along with increasing hypercarbia. Interventions, including an increase in supplemental oxygen, administration of IV and aerosolized steroids, aerosolized racemic epinephrine, aerosolized bronchodilators, and inhaled heliox, did not improve the child's status. The results of arterial blood gas (ABG) measurements deteriorated to a pH of 7.11, PaCO2 of 76 mm Hg, and PaO2 of 171 mm Hg.
In an attempt to avoid further airway trauma from tracheal intubation, NPPV via a nasal mask was instituted in the timed spontaneous mode, using a ventilatory support system (BiPAP; Respironics; Murrysville, PA). Initially, the inspiratory positive airway pressure (IPAP) was set at 10 cm H2O, and the expiratory positive airway pressure (EPAP) was set at 5 cm H2O, with a mechanical respiratory rate of 15 breaths/min, while the child adjusted to the device. A 3-L/min flow of oxygen with a fraction of inspired oxygen (FIO2) of 1.0 was introduced at the mask. Subsequent changes in the level of ventilatory support were made based on the patient's lung auscultation findings, level of comfort, and ABG results. A nasogastric tube was electively placed to minimize gastric distention. Over the course of an hour, the IPAP was increased to 15 cm H2O, and the EPAP was increased to 8 cm H2O. The mechanical respiratory rate was increased over the following 9 h to 25 breaths/min, and the FIO2 was decreased to 0.7, while the gas flow was maintained at 3 L/min. Following the institution of NPPV, ABG results improved, demonstrating a pH of 7.31, PaCO2 of 46 mm Hg, and PaO2 of 84 mm Hg, 3 h after therapy was started. The child required infusions of medications for sedation and to maintain placement of the nasal mask. By the second day of NPPV, the child was generally more comfortable and required less sedative medications.
NPPV was used for 41 h with no change in the preset ventilator settings, except for a decrease in the FIO2. Over this period of time, the patient's respiratory status and ABG results continued to improve, with a resolution of the stridor and an ABG just prior to discontinuation of NPPV showing a pH of 7.45, PaCO2 of 44 mm Hg, and PaO2 of 85 mm Hg. NPPV was discontinued on postoperative day 24 with no recurrence of airway obstruction or respiratory insufficiency. On postoperative day 28, the patient was transferred to a hospital closer to his home to complete his recovery.
Case 2
A 22-month-old female patient was admitted to the PICU after
elective laryngoscopy, tracheoscopy, and LTR. The patient was born
after a full-term gestation with an interrupted aortic arch, an atrial
septal defect, and a ventricular septal defect. She underwent repair of
these congenital heart defects during infancy and subsequently required
a tracheostomy for severe subglottic stenosis.
Laryngotracheal reconstruction was performed with an anterior cricoid split and an autogenous thyroid cartilage graft placement. She was admitted postoperatively to the PICU with a 4.0-mm ID nasotracheal tube sutured in place. Sedation and analgesia were maintained with continuous medication infusions, and neuromuscular blockade was achieved with intermittent doses of medication. Episodes of atelectasis were responsive to chest physiotherapy and suctioning. The patient developed an air leak around her nasotracheal tube on postoperative day 5, and her trachea was extubated after receiving IV steroids. The child was awake and agitated prior to tracheal extubation, but she subsequently became more somnolent and developed signs of upper airway obstruction. She received aerosolized epinephrine twice without relief and had a worsening of her respiratory status. An ABG revealed a pH of 7.29, PaCO2 of 67 mm Hg, and PaO2 of 206 mm Hg, while she was receiving supplemental oxygen.
NPPV in the spontaneous mode via a nasal mask (Nellcor Puritan Bennett; Pleasanton, CA) was initiated in an attempt to avoid tracheal intubation and further airway trauma, as well as to decrease the need for ongoing sedation. Initial ventilatory settings consisted of an IPAP of 10 cm H2O and an EPAP of 5 cm H2O, with a 2.5 L/min flow of oxygen (FIO2 being 1.0) introduced at the mask. The flow of oxygen was gradually decreased based on pulse oximetry measurements, and after 3 h, her ABG results improved to a pH of 7.36, PaCO2 of 53 mm Hg, and PaO2 of 94 mm Hg. No additional sedation was required during this time.
At this level of support, NPPV was continued for 24 h. Prior to the discontinuation of NPPV, the ABG results had improved to a pH of 7.40, PaCO2 of 48 mm Hg, and PaO2 of 92 mm Hg. The child's respiratory status continued to improve, with no further evidence of upper airway obstruction, and she was discharged to her home on postoperative day 10.
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Discussion |
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We have reported the cases of two children who had undergone LTR and subsequently developed upper airway obstruction and respiratory failure following tracheal extubation. Tracheal reintubation was avoided in both cases by the use of NPPV. NPPV facilitated the reversal of respiratory failure without the trauma of tracheal intubation and allowed time for the resolution of tracheal edema following tracheal extubation. One patient required sedation while receiving NPPV, but at lower doses than when tracheally intubated, whereas the second patient required no sedation. Neither patient experienced any complications related to the use of NPPV, which was required for only a short period of time, and both patients subsequently did well.
NPPV has been employed extensively in adults with both acute and chronic respiratory failure.3 4 5 6 More recently, there have been reports in the literature about the use of NPPV in pediatric patients with acute respiratory failure.7 8 9 10 11 These reports suggest that NPPV may prevent tracheal intubation in many patients with minimal complications. By avoiding tracheal intubation, NPPV may allow time for airway healing and resolution of edema while providing ventilatory support and airway stenting. The mode of NPPV employed for any given patient (spontaneous, timed/spontaneous, or timed) will depend on the needs of the patient, but in general we prefer to utilize a spontaneous mode with NPPV to allow mechanical support and synchrony with the patient's respiratory effort. Likewise, the initial levels of IPAP and EPAP will depend on the patient's needs. We generally start with relatively low levels of pressure, such as an IPAP of 6 to 10 cm H2O and an EPAP of 3 to 5 cm H2O, allowing the child to accommodate to the mask pressure. Subsequently, IPAP and EPAP may be increased as needed, based on the patient's physical examination, pulse oximetry measurements, and ABG results. NPPV cannot be performed when the size of the nasal mask is too large for the child, but NPPV has been successfully performed in infants as young as 4 months.9 Furthermore, tracheal intubation is appropriate in those cases where hemodynamic instability or a loss of protective airway reflexes has occurred.
The potential complications of NPPV include nasal skin breakdown, gastric distention, and aspiration of gastric contents. The breakdown of skin over the nasal bridge can be minimized by the use of protective padding but must be monitored carefully. Gastric distention has been uncommon in pediatric studies7 8 9 10 11 and can be minimized with the use of a nasogastric tube to decompress the stomach if needed. The aspiration of gastric contents has not been reported thus far in the pediatric population. In children, sedation may be necessary to facilitate tolerance of the mask but should not be more than that needed while the patient is tracheally intubated. Increasing acceptance of the mask may develop over time and allow sedation use to be decreased or discontinued. The risk of gastric reflux and aspiration may increase, however, with the use of sedation. Tracheal intubation may provide relative protection against gastric aspiration, so that this benefit may need to be weighed against the risks associated with tracheal intubation in those patients whose airway protective reflexes have been blunted by sedation. A theoretical danger of NPPV in children who have received LTR is that the pressure delivered by the mask could cause airway distention and injury at the surgical site. Although no evidence of this problem was apparent in our patients, further research into this possibility is warranted. Furthermore, the minimal levels of IPAP and EPAP needed to maintain the desired clinical effects should be employed.
Our cases are unique in that they describe for the first time the use of NPPV in children who have respiratory failure secondary to upper airway obstruction that developed after LTR. NPPV served as a bridge between mechanical ventilation (via a tracheal tube) and spontaneous breathing, allowing time for a critical decrease in airway edema while avoiding further airway trauma. It is possible that NPPV will also be useful in the treatment of children with respiratory failure secondary to airway obstruction of different etiologies. Before its role can be completely delineated, further evaluation of NPPV is needed in the management of respiratory failure associated with upper airway obstruction after LTR.
In conclusion, we have described the cases of two children who developed respiratory failure secondary to airway obstruction following LTR and who were successfully managed with NPPV. NPPV may be considered as a therapeutic option in such situations, assuming that close cardiorespiratory monitoring is maintained and that individuals skilled in airway management are readily available.
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Footnotes |
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Abbreviations: ABG = arterial blood gas; EPAP = expiratory positive airway pressure; FIO2 = fraction of inspired oxygen; ID = internal diameter; IPAP = inspiratory positive airway pressure; LTR = laryngotracheal reconstruction; NPPV = noninvasive positive-pressure ventilation; PICU = pediatric ICU
Received for publication October 19, 1998. Accepted for publication February 24, 1999.
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