The Science Journal of the American Association for Respiratory Care

1996 OPEN FORUM Abstracts

SYNCHRONIZED NASAL VENTILATION IN THE PRETERM INFANT: CASE STUDY

Steven E. Sittig R.R.T., P/P Specialist, Douglas P. Derleth, M.D.; Mayo Clinic, Rochester, Minnesota

Introduction: While nasal ventilation has increased in popularity with the adult and pediatric population, there is very little in the literature regarding its application to noninvasive support of the premature infant.

Case Summary: The patient was a 23 and 4/7 week gestation, 515-gm female born precipitously in a breech presentation after a placental abruption. The infant was intubated and Survanta was administered. The patient was placed on SIMV, rate 70; peak pressure, 23 cm H_{2}O; PEEP, 4cm H_{2}O (23/4); inspiratory time (IT), 0.2 sec; and FIO_{2}, 1.0. Tidal volumes utilizing a Bear NVM-1 were kept near 6 mL/kg (3.2 cc). The patient was started on low-dose dexamethasone (0.03 mg b.i.d) and aminophylline. On day 3 of life, a head ultrasound was negative. The ventilator settings were gradually weaned over a 4-day period to a SIMV rate of 20, 12/2, 0.15 sec IT, and FIO_{2} of 0.23. The patient was extubated and placed on an Infrasonic Infant Star with Starsync module and a RCI Hudson Nasal CPAP circuit and a CPAP hat with chin strap of our own design. An orogastric tube was in place to vent swallowed air. The patient was placed on an assist control rate of 30, 19/3, 0.15 IT, and 23% FIO_{2} via nasal prongs. An inline aerosol with racemic epinephrine was delivered during the assist control mode to decrease post-extubation edema. The TcPCO_{2} decreased from 55 to 36. The patient was changed to a nasal SIMV rate of 30, 19/3, 0.2 sec IT, and 0.24 FIO_{2}. Good chest excursion was seen with synchronized breaths. Over 1 hour, the SIMV rate was decreased to 10 bpm and pressures to 14/4. Twelve hours post-extubation, the patient was placed on nasal CPAP 4 cm H_{2}O with a 10-sec delay to a temporary apnea backup rate of 30 bpm. An arterial blood gas (ABG) drawn during a spontaneous respiratory rate of 50 bpm was PaO_{2}, 72; PCO_{2}, 27; pH, 7.40 with base -6. A post-extubation chest x-ray showed no atelectasis. The patient was maintained on these settings for 4 days. At 8 days of age, the patient exhibited retractions, apnea spells (13 in 7 hours) and increased TcPCO_{2} readings. An ABG drawn at this time revealed a combined respiratory and metabolic acidosis, PaO_{2}, 69; PCO_{2}, 63; pH, 7.17 with base -6. The patient was placed on nasal assist control rate of 20, 18/4, 0.2 IT, and 0.22 FIO_{2} while another inline racemic epinephrine aerosol was given and a doxapram drip was added. Good chest excursion was seen with synchronized breaths. A follow-up ABG revealed PaO_{2}, 65; PCO_{2}, 54; pH 7.30 with base -1. The patient was returned to nasal CPAP 4 cm H_{2}O with a backup apnea rate of 30 and a 10-sec alarm delay activation time. The patient required periods of nasal SIMV on three other occasions for a total of 6 days. The CPAP was slowly weaned to 3 cm H_{2}O, the apnea delay time increased to 20 sec, then trials off CPAP began and gradually increased in duration. On day 82 of life, the CPAP was discontinued. The patient was discharged at 13 weeks of age, weighing 2020 gm, without home oxygen or diuretic requirements.

Discussion: Utilization of nasal ventilation/CPAP is an option in support of early extubation in the preterm population. Over the past 5 years, we have found both the apnea backup feature and nasal SIMV useful in supporting the early extubation of premature babies. Nasal SIMV can be used to support a baby through difficult periods while the underlying problem is solved without resorting to reintubation.

Reference: OF-96-025

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