Effects of dexamethasone on pulmonary function following extubation. Routine use of dexamethasone for the prevention of postextubation respiratory distress. Effectiveness of dexamethasone in preventing extubation failure in preterm infants at increased risk for airway edema.
Dexamethasone is often given to intubated neonates to facilitate successful extubation. To study the effects of dexamethasone on pulmonary function immediately following extubation, we conducted a randomized, blinded, placebo-controlled trial in 51 infants. All infants had been intubated for a minimum of 3 days but no more than 30 days. Mean weight at extubation was 2.41 kg in treated infants, 2.25 kg in control infants. When infants were deemed ready for extubation, dexamethasone 0.5 mg/kg/dose or an equal volume of normal saline was given in three doses 8 hours apart. The final dose was given 1 hour before extubation. Esophageal pressure, air flow integrated to tidal volume (Vt), respiratory rate, and heart rate were measured before extubation, immediately following extubation, and every 20 minutes for 80 minutes. Total pulmonary resistance (RTP), dynamic lung compliance (CL), and minute ventilation (VE) were calculated. Forty-two infants completed the study; 19 infants received dexamethasone and 23 received placebo. There was no difference between the two groups in gestational age, weight at study, or length of intubation. Vt, RTP, VE, and CL were not significantly different between the two groups over time; however, RTP increased over time in the placebo group. Heart rate was significantly lower in the dexamethasone group. We conclude that dexamethasone appears to have limited effect on pulmonary function immediately following extubation in the population studied. Further studies should evaluate the drug effect beginning at least 1 hour after extubation. We evaluated the routine use of dexamethasone for the prevention of postextubation respiratory distress by entering 60 ventilated infants into a prospective, randomized, blinded study. Thirty minutes before extubation, 30 infants were given a single dose of intravenous dexamethasone (0.25 mg/kg), and 30 infants received saline placebo. Infants were intubated orotracheally for at least 48 hours following a single intubation and were maintained on low ventilator settings (F10(2) less than 0.35, intermittent mandatory ventilation [IMV] less than 6, positive end-expiratory pressure [PEEP] less than 4) at least 12 hours before extubation. Following extubation, all infants weighing less than 1500 g were routinely placed on nasal continuous positive airway pressure (NCPAP). There was no difference between the two groups in postextubation Downes' score, serum pH, PCO2, or oxygen requirement at 30 minutes, 6 hours, and 24 hours. Respiratory acidosis occurred in one steroid-treated patient and in two placebo-treated infants. Stridor occurred in four infants in each group. No infant developed postextubation lobar atelectasis or required reintubation. We conclude that prophylactic administration of dexamethasone does not improve the immediate postextubation course of infants following a single intubation and that its routine use at the time of extubation is not indicated. We studied 50 preterm infants who had multiple or traumatic endotracheal intubations, or whose duration of endotracheal intubation was > or = to 14 days, and who were considered at high risk for airway edema. These infants were enrolled in a prospective, randomized, controlled clinical trial to assess whether prophylactic dexamethasone therapy would be effective in the prevention of postextubation stridor and respiratory distress. At study entry, both groups had similar weights, postnatal ages, methylxanthine use, ventilator settings, blood gas values, and pulmonary function test results (dynamic compliance, total respiratory resistance, tidal volume, peak-to-peak transpulmonary pressure, minute ventilation, and peak inspiratory and expiratory flow rates). Patients underwent blood gas studies, physical examinations, and pulmonary function testing at baseline (4 hours before extubation) and again 2 to 4 hours and 18 to 24 hours after extubation. Twenty-seven infants received dexamethasone, 0.25 mg/kg per dose, at baseline, and then every 8 hours for a total of three doses; 23 infants received saline solution at corresponding times. Eighteen to twenty-four hours after extubation, total pulmonary resistance increased by 225% from baseline in the control group compared with 33% in the dexamethasone group (p < 0.006), and the dexamethasone group had a greater tidal volume, a greater dynamic compliance, and a lower arterial carbon dioxide pressure. Of 23 control infants, 10 had postextubation stridor compared with 2 of 27 dexamethasone-treated patients (p < 0.006). Of the 23 control patients, 4 required reintubation compared with none of the treated group (p < 0.05). We conclude that the prophylactic use of corticosteroids for the prevention of postextubation stridor and respiratory distress is efficacious in low birth weight, high-risk preterm infants.
Implications for practiceDexamethasone reduces the need for endotracheal reintubation of neonates after a period of IPPV. In view of the lack of effect in low-risk infants and the documented and potential side effects, it appears reasonable to restrict its use to infants at increased risk for airway edema and obstruction, such as those who have received repeated or prolonged intubations.
Implications for researchIssues of dosage and applicability to the extremely low birthweight population could be addressed in future trials. Outcomes such as chronic lung disease, duration of assisted ventilation and length of hospital stay as well as long-term neurodevelopment should also be examined.