Obtaining a patent airway and providing ventilation are fundamental to pediatric CPR, especially since most pediatric cardiac arrests have a primary respiratory cause. Initial assessment of a patient in respiratory failure must determine the urgency of medical intervention – a decision usually reached within the first minutes of the clinical encounter. The most helpful indicators are vital signs, the work of breathing, and level of consciousness.
A patient with very rapid respirations, significant retractions, head bobbing, nasal flaring, and grunting will require aggressive respiratory support. Signs of severe hemodynamic compromise – mottled extremities and low blood pressure leading to a decreased response to painful stimuli – require an ABC response: emergent Airway control, Breathing and Circulatory support. Decreased responsiveness also indicates necessary emergent airway control and breathing support. The appropriate intervention should be immediate – not delayed to obtain results of a blood gas or chest radiograph, for example.
Emergent pediatric airway control will be smoother if all the necessary equipment is gathered. One of the most frequent mistakes involves the selection of appropriate suction equipment; a large gauge catheter will always be more effective in clearing secretions or vomit (a 14 Fr catheter should be used for an infant).
Identify the challenge
The first step is to identify a potentially difficult airway. Several anatomical features will offer important clues: abnormal facial anatomy (Pierre Robin syndrome, macroglossia, and obesity), facial burns, cervical spine immobility, pharyngeal and laryngeal abnormalities, and anterior mediastinal tumors.
However, it is often impossible to predict difficulties accurately. For example, one of our recent patients was a 4-month-old male presenting with stridorthat he had since birth, and respiratory distress caused by respiratory syncytial virus. He was tachypneic, tachycardic, and hypoxic, with significant retractions. The process of intubation was initiated. After rapid sequence induction, the airway was visualized, and a subglottic cyst obstructing the airway was discovered. (See Figures, page 20.) Passing an endotracheal tube was not possible. A laryngeal mask airway (LMA) was inserted and allowed for good bag mask ventilation (BMV) while transporting the patient to the OR for laser removal of the cyst.
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BMV is a fundamental
BMV is the most widely employed technique to provide emergent ventilation, and it is a fundamental skill for any practitioner managing pediatric airways. During BMV, positioning the patient with the head in midline, using a jaw thrust to open the airway, and obtaining a good seal with the mask by lifting the
mandible facilitates effective ventilation.
Studies suggest BMV is an effective strategy to support breathing in infants and children in the prehospital setting and might be safer than ETT ventilation for out-of-hospital resuscitation and transport. But in the case of a known difficult airway, it is better to help the patient maintain a patent airway and effective respiration without intubation until care can be provided in a facility with a high level of pediatric airway management expertise.
For example, a patient with Pierre Robin syndrome or with anterior mediastinal mass should be placed prone and provided a high flow nasal cannula while transport is arranged.
Pediatric intubation is an infrequent procedure outside of specialized hospitals, making skill retention difficult. Also, pediatric emergent airway management raises technical challenges related to anatomy and physiology.
Several anatomical characteristics specific to young children add to the difficulty of obtaining good positioning and visualization: large head size proportional to body size, relatively larger tongue and epiglottis, and more cephalad larynx with anterior angled vocal cords.
Physiologic differences in children add further complexity. Resting oxygen consumption in newborns is double that of an adult, leading to faster desaturation time. Young
children are also more prone to bradycardia.
Given these challenges, it is not surprising that pediatric airway management is associated with a high rate of unwanted events, even in the hands of an experienced practitioner.
A recent study analyzing the tracheal intubation procedure in a large pediatric intensive care unit revealed the incidence of esophageal intubation was 11 percent; desaturation less than 80 percent was reported in 27.7 percent of intubations, and successful airway placement occurred only after more than two intubation attempts in 15.3 percent of cases.
Novel ventilation devices are used to rescue failed ETT attempts, and new technologies are available to improve airway visualization
The LMA is one of the few supraglottic rescue devices used to facilitate ventilation following failed intubations. There are two other supraglottic rescue devices with limited use in pediatrics due to fewer size options for patients under 35kg: the esophageal-tracheal combination tube and laryngeal tube.
LMAs are widely used during elective adult and pediatric anesthesia cases. An LMA consists of an inflatable silicone ring attached to a flexible tube that can be placed blindly in the oropharynx. The ring achieves a low-pressure seal between the tube and the airway without insertion into the larynx.
The 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science recommend LMAs as an acceptable solution in the hands of the experienced practitioner to provide a patent airway and support ventilation when BMV is unsuccessful and when endotracheal intubation is not possible.
A study found the mean time to effective ventilation during simulated arrest was twice as long when using ETT than when using LMAs (23 seconds vs. 46 seconds). LMAs were malpositioned in 9.5 percent of cases, whereas intubation attempts resulted in 17 percent esophageal intubations and 27 percent right main stem intubations – a total of 44 percent undesired events during ETT attempts.
In younger children, LMA insertion is associated with a higher incidence of complications compared with older children and adults. In a survey of 1,400 children, the overall problem rate was 11.5 percent, mostly related to the use of the smallest size laryngeal mask.
The recent use of video laryngoscopy allows glottic visualization without creating a direct line of sight through alignment of the oral, pharyngeal, and tracheal axes, and could potentially improve the intubation success rate of the difficult airway. However, unlike the results seen in adult medicine, first pass success seems to be lower and time to intubation longer in pediatric patients when video laryngoscopy is used in comparison to intubation using a Macintosh blade.
The bottom line
Emergent management of the pediatric airway is challenging. ETT is the preferred means of supporting oxygenation and ventilation; however, success rates in children are lower than in adults. Rescue ventilation devices such as LMAs offer effective alternatives to BMV in failed intubation and arrest scenarios. Pediatric providers must maintain familiarity with emerging rescue ventilation devices along with basic skills.
Look under the “Magazine” tab at www.advanceweb.com/respiratory for a resource list.
Mara Nitu, MD, is medical director of the PICU at Riley Hospital for Children, Indianapolis, and associate professor of clinical pediatrics at Indiana University School of Medicine. Howard Eigen, MD, is director of pediatric pulmonology, critical care, and allergy at Riley Hospital for Children, and Billie Lou Wood professor of pediatrics and associate chairman of clinical affairs at Indiana University School of Medicine.