August 21, 2001

Effect of jaw-thrust and continuous positive airway pressure on tidal breathing in deeply sedated infants.

Hammer J, Reber A, Trachsel D, Frei FJ. J Pediatr 2001; 138: 826-30

Anesthesiologists are well trained to recognize hypoventilation and partial airway obstruction in children or adults. Hammer et al. examined the effects of continuous positive airway pressure (CPAP) and a jaw thrust upon tidal breathing, peak inspiratory flow rate, peak expiratory flow rate, and quality of respiratory flow tracings in 13 infants breathing spontaneously and sedated with propofol.[1] They demonstrated very significant improvements in tidal volume, minute ventilation, peak tidal inspiratory flow, and peak tidal expiratory flow with a jaw thrust maneuver. At the same time, there was no change in heart rate or respiratory rate suggesting a stable depth of sedation. Conversely CPAP significantly improved respiratory parameters but not to the same degree as the jaw thrust. Their simultaneous fiberoptic evaluation demonstrated an upward displacement of the epiglottis and overall enlargement of the laryngeal inlet. The upward displacement of the epiglottis with a jaw thrust has previously been suggested by Fink to help break pediatric laryngospasm.[2] The authors speculated that a followup study might examine combination of the jaw thrust with the application of CPAP as we often times do during general anesthesia. This paper is a brief report that can be used to teach our pediatric colleagues and others why the jaw thrust is such a useful maneuver to clear the airway of unconscious patients, especially in an emergency situation.

I have always taught my residents that, rather than performing positive pressure controlled ventilation, that the simple application of CPAP often times stents the airway open. This is clinically important during the early phases of anesthesia induction in infants and children by face mask since it thereby allows spontaneous respirations. By avoiding controlled ventilation, the depth of anesthesia is autoregulated by the infants thus avoiding potential overdose particularly with halothane, i.e., controlled ventilation = anesthetic overdose and spontaneous respirations = avoiding an overdose. Sometimes in addition to CPAP, a jaw thrust is also required to clear the airway and provide better gas exchange. The Hammer paper clearly demonstrates scientifically the measures I have always taught my residents because that is what was taught to me during my residency.

References:

1. Hammer J, Reber A, Trachsel D, Frei FJ: Effect of jaw-thrust and continuous positive airway pressure on tidal breathing in deeply sedated infants. J Pediatr 2001; 138: 826-30
2. Fink BR: The etiology and treatment of laryngeal spasm. Anesthesiology. 1956; 17: 569-77

Effect of jaw-thrust and continuous positive airway pressure on tidal breathing in deeply sedated infants.

AUTHORS:
Hammer J, Reber A, Trachsel D, Frei FJ

SOURCE:
J Pediatr 2001; 138: 826-30

OBJECTIVES: To examine the physiologic impact of the jaw-thrust maneuver or the administration of continuous positive airway pressure (CPAP) on tidal breathing in deeply sedated infants.Study design: Prospective, non-randomized study of infants undergoing elective fiberoptic bronchoscopy while sedated with intermittent doses of propofol. METHODS: Spontaneous tidal breathing measured in the supine position by means of a spirometer attached to a bronchoscopy face mask. Tidal breaths were recorded under the following conditions: (1) neutral sniffing position, (2) jaw-thrust, (3) neutral sniffing position, and (4) CPAP of 5 cm H(2)O. Improvement was defined as a change of more than twice the coefficient of variation of repeated measurements of tidal volume and flows from baseline. RESULTS: Jaw-thrust increased tidal volume, minute ventilation, and peak tidal inspiratory and expiratory flows significantly in all 13 infants studied (mean +/- SEM age = 8 +/- 2 months). CPAP increased peak tidal inspiratory and expiratory flows by more than twice the coefficient of variation of baseline measurements in 6 patients and tidal volume and minute ventilation in 5 of 10 patients studied. CONCLUSION: Jaw-thrust and CPAP are effective techniques to improve ventilation of sedated infants undergoing interventions that compromise upper airway patency.