Limitations of theophylline in the treatment of apnea of prematurity

Methylxanthine for the prevention and treatment of apnea in preterm infants

BACKGROUND

Very preterm infants often require respiratory support and are therefore exposed to an increased risk of chronic lung disease and later neurodevelopmental disability. Although methylxanthines are widely used to prevent and treat apnea associated with prematurity and to facilitate extubation, there is uncertainty about the benefits and harms of different types of methylxanthines.

OBJECTIVES

To assess the effects of methylxanthines on the incidence of apnea, death, neurodevelopmental disability, and other longer-term outcomes in preterm infants (1) at risk for or with apnea, or (2) undergoing extubation.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, two other databases, and three trial registers (November 2022).

SELECTION CRITERIA

We included randomized trials in preterm infants, in which methylxanthines (aminophylline, caffeine, or theophylline) were compared to placebo or no treatment for any indication (i.e. prevention of apnea, treatment of apnea, or prevention of re-intubation).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods and GRADE to assess the certainty of evidence.

MAIN RESULTS

We included 18 studies (2705 infants), evaluating the use of methylxanthine in preterm infants for: any indication (one study); prevention of apnea (six studies); treatment of apnea (five studies); and to prevent re-intubation (six studies). Death or major neurodevelopmental disability (DMND) at 18 to 24 months. Only the Caffeine for Apnea of Prematurity (CAP) study (enrolling 2006 infants) reported on this outcome. Overall, caffeine probably reduced the risk of DMND in preterm infants treated with caffeine for any indication (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.78 to 0.97; risk difference (RD) -0.06, 95% CI -0.10 to -0.02; number needed to treat for an additional beneficial outcome (NNTB) 16, 95% CI 10 to 50; 1 study, 1869 infants; moderate-certainty evidence). No other trials reported DMND. Results from the CAP trial regarding DMND at 18 to 24 months are less precise when analyzed based on treatment indication. Caffeine probably results in little or no difference in DMND in infants treated for prevention of apnea (RR 1.00, 95% CI 0.80 to 1.24; RD -0.00, 95% CI -0.10 to 0.09; 1 study, 423 infants; moderate-certainty evidence) and probably results in a slight reduction in DMND in infants treated for apnea of prematurity (RR 0.85, 95% CI 0.71 to 1.01; RD -0.06, 95% CI -0.13 to 0.00; NNTB 16, 95% CI 7 to > 1000; 1 study, 767 infants; moderate-certainty evidence) or to prevent re-intubation (RR 0.85, 95% CI 0.73 to 0.99; RD -0.08, 95% CI -0.15 to -0.00; NNTB 12, 95% CI 6 to >1000; 1 study, 676 infants; moderate-certainty evidence). Death. In the overall analysis of any methylxanthine treatment for any indication, methylxanthine used for any indication probably results in little or no difference in death at hospital discharge (RR 0.99, 95% CI 0.71 to 1.37; I2 = 0%; RD -0.00, 95% CI -0.02 to 0.02; I2 = 5%; 7 studies, 2289 infants; moderate-certainty evidence). Major neurodevelopmental disability at 18 to 24 months. In the CAP trial, caffeine probably reduced the risk of major neurodevelopmental disability at 18 to 24 months (RR 0.85, 95% CI 0.76 to 0.96; RD -0.06, 95% CI -0.10 to -0.02; NNTB 16, 95% CI 10 to 50; 1 study, 1869 infants; moderate-certainty evidence), including a reduction in the risk of cerebral palsy or gross motor disability (RR 0.60, 95% CI 0.41 to 0.88; RD -0.03, 95% CI -0.05 to -0.01; NNTB 33, 95% CI 20 to 100; 1 study, 1810 infants; moderate-certainty evidence) and a marginal reduction in the risk of developmental delay (RR 0.88, 95% CI 0.78 to 1.00; RD -0.05, 95% CI -0.09 to -0.00; NNTB 20, 95% CI 11 to > 1000; 1 study, 1725 infants; moderate-certainty evidence). Any apneic episodes, failed apnea reduction after two to seven days (< 50% reduction in apnea) (for infants treated with apnea), and need for positive-pressure ventilation after institution of treatment. Methylxanthine used for any indication probably reduces the occurrence of any apneic episodes (RR 0.31, 95% CI 0.18 to 0.52; I2 = 47%; RD -0.38, 95% CI -0.51 to -0.25; I2 = 49%; NNTB 3, 95% CI 2 to 4; 4 studies, 167 infants; moderate-certainty evidence), failed apnea reduction after two to seven days (RR 0.48, 95% CI 0.33 to 0.70; I2 = 0%; RD -0.31, 95% CI -0.44 to -0.17; I2 = 53%; NNTB 3, 95% CI 2 to 6; 4 studies, 174 infants; moderate-certainty evidence), and may reduce receipt of positive-pressure ventilation after institution of treatment (RR 0.61, 95% CI 0.39 to 0.96; I2 = 0%; RD -0.06, 95% CI -0.11 to -0.01; I2 = 49%; NNTB 16, 95% CI 9 to 100; 9 studies, 373 infants; low-certainty evidence). Chronic lung disease. Methylxanthine used for any indication reduces chronic lung disease (defined as the use of supplemental oxygen at 36 weeks' postmenstrual age) (RR 0.77, 95% CI 0.69 to 0.85; I2 = 0%; RD -0.10, 95% CI -0.14 to -0.06; I2 = 18%; NNTB 10, 95% CI 7 to 16; 4 studies, 2142 infants; high-certainty evidence). Failure to extubate or the need for re-intubation within one week after initiation of therapy. Methylxanthine used for the prevention of re-intubation probably results in a large reduction in failed extubation compared with no treatment (RR 0.48, 95% CI 0.32 to 0.71; I2 = 0%; RD -0.27, 95% CI -0.39 to -0.15; I2 = 69%; NNTB 4, 95% CI 2 to 6; 6 studies, 197 infants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Caffeine probably reduces the risk of death, major neurodevelopmental disability at 18 to 24 months, and the composite outcome DMND at 18 to 24 months. Administration of any methylxanthine to preterm infants for any indication probably leads to a reduction in the risk of any apneic episodes, failed apnea reduction after two to seven days, cerebral palsy, developmental delay, and may reduce receipt of positive-pressure ventilation after institution of treatment. Methylxanthine used for any indication reduces chronic lung disease (defined as the use of supplemental oxygen at 36 weeks' postmenstrual age).

Caffeine Citrate for Apnea of Prematurity: A Prospective, Open-Label, Single-Arm Study in Chinese Neonates

Background: Caffeine citrate has been approved in China for the management of apnea of prematurity. This clinical trial was conducted as a condition of regulatory approval. The aim was to confirm the efficacy of caffeine citrate in the treatment of recurrent intermittent hypoxia and bradycardia in preterm newborns with primary apnea. Objectives: The primary outcome was the change from baseline in the number of apnea events after loading dose administration of caffeine citrate. Secondary efficacy outcomes included the change from baseline in apnea events after 2 and 4 weeks of maintenance doses. Methods: This was a multicenter, prospective longitudinal open-label, single-arm study. Neonates who had experienced at least four apnea events during a 24 h period received a loading dose of caffeine citrate 20 mg/kg; those who required additional maintenance doses received 5 mg/kg/day (titrated up to 10 mg/kg/day in case of insufficient response). The number of apnea events was recorded for 6-12 h prior to the loading dose (baseline), and for 12 h post-dose, following the loading dose and at Weeks 2 and 4 (during maintenance). Results: A total of 247 neonates received the loading dose, who had a significant reduction from baseline of 3.9 events (p < 0.001) in the mean number of apnea events. The subset of neonates who required maintenance doses also had significant reductions in the number of events at all visits (p < 0.001 for all). A total of 79.4% of participants had at least one adverse event, but only one non-serious and no serious events were considered related to treatment. Conclusions: In this large, prospective, open-label study, premature infants with a history of apnea who received caffeine citrate were significantly less likely to experience further apnea events.

High versus low-dose caffeine for apnea of prematurity: a randomized controlled trial

The optimum caffeine dose in preterm infants has not been well investigated. We aimed to compare the efficacy and safety of high versus low-dose caffeine citrate on apnea of prematurity (AOP) and successful extubation of preterm infants from mechanical ventilation. We compared high-dose (loading 40 mg/kg/day and maintenance of 20 mg/kg/day) versus low-dose (loading 20 mg/kg/day and maintenance of 10 mg/kg/day) caffeine citrate in preterm infants <32 weeks gestation, presented with AOP within the first 10 days of life. A total of 120 neonates (60 in each group) were enrolled. High-dose caffeine was associated with a significant reduction in extubation failure in mechanically ventilated preterm infants (p<0.05), the frequency of apnea (p<0.001), and days of documented apnea (p<0.001). High-dose caffeine was associated with significant increase in episodes of tachycardia (p<0.05) without a significant impact on physician decision to withhold caffeine.

CONCLUSION

The use of higher, than current standard, dose of caffeine may decrease the chance of extubation failure in mechanically ventilated preterm infants and frequency of AOP without significant side effects.

WHAT IS KNOWN

• Caffeine therapy for treatment of apnea of prematurity has been well established over the past few years. The optimal loading and maintenance dose of caffeine in preterm infants is not well-studied. What is New: • This double blind randomized controlled trial demonstrated that using a higher, than current standard, loading and maintenance doses of caffeine for treatment of apnea in preterm infants is well tolerated and significantly decrease the frequency of apnea.

Theophylline and gastric emptying in very low birthweight neonates: a randomised controlled trial

BACKGROUND

Theophylline treatment causes side effects such as tachycardia, hyperglycaemia, abdominal distension, and vomiting. The latter two are probably the result of delayed gastric evacuation.

OBJECTIVE

To study the effect of theophylline on gastric emptying time in preterm infants.

PATIENTS

The subjects were 18 premature neonates with a mean (SD) birth weight of 1302 (240) g and a mean (SD) gestational age of 28.7 (1.9) weeks.

MAIN OUTCOME MEASURES

In each case, gastric emptying was measured on two occasions: once when the newborns were being treated with theophylline and once when they were not. Half of the cases were randomised to receive theophylline before the initial measurement. The opposite was applied for the rest. Gastric emptying was assessed ultrasonically by measuring the change in antral cross sectional area (ACSA) at regular intervals over 120 minutes.

RESULTS

The mean (SD) ACSA half time in the newborns receiving theophylline was 52 (19) minutes compared with 37 (16) minutes in those not receiving theophylline. This difference is significant (p < 0.05).

CONCLUSIONS

Treatment with theophylline seems to delay gastric emptying in very low birthweight neonates, and this must be taken into consideration when this drug is used to treat apnoea of prematurity.