Effect of caffeine on superior mesenteric artery blood flow velocities in preterm neonates

Gastrointestinal effects of caffeine in preterm infants: a systematic review and Bayesian meta-analysis

OBJECTIVE

Caffeine is widely used in preterm infants to prevent or treat apnoea of prematurity. Adverse gastrointestinal effects of caffeine have not been thoroughly researched in preterm infants. With this systematic review and meta-analysis, we aim to summarise the results of trials on the gastrointestinal effects of caffeine in preterm infants.

DESIGN

We searched MEDLINE, Web of Science, Scopus and ClinicalTrials.gov up to 21 April 2023. We included randomised controlled trials assessing caffeine versus placebo in preterm neonates and reporting gastrointestinal side effects. Risk of bias was assessed using the Cochrane Risk of Bias tool. A Bayesian meta-analysis was performed to estimate the pooled OR of gastrointestinal side effects.

RESULTS

Nine trials involving 2746 preterm infants were analysed. Seven trials assessing necrotising enterocolitis and four trials assessing feeding intolerance in our meta-analysis found no differences between caffeine and placebo (OR=1.007 (95% credible interval 0.021, 5.462), I2=97.4%, and OR=1.266 (95% credible interval 0.064, 28.326), I2=84.8%, respectively). Four trials assessed the outcomes spontaneous intestinal perforation, constipation, gastrointestinal disorder (composite outcome: gastro-oesophageal regurgitation or dilated bowel loops), age at oral feeding and cholestasis syndrome and found no differences between groups. One trial assessed the outcomes gastro-oesophageal symptoms and duration of tube feeding and found that caffeine was associated with a reduced burden of gastro-oesophageal reflux symptoms at 2 weeks (p<0.05), but not at term.

CONCLUSIONS

According to this systematic review and meta-analysis, the use of caffeine at usual doses in preterm infants does not seem to be associated with significant gastrointestinal adverse effects.

Administration time of caffeine in preterm infants: systematic review and meta-analysis

To assess the ideal time for caffeine administration in preterms, identifying its effects and safety. Study Design: Meta-analysis conducted including preterms <32 weeks GA or BW < 1500 g, comparing caffeine administration time: <24 x ≥24HOL, <48 x ≥48HOL, <72 x ≥72HOL. 18 studies included 76.998 patients. The median age of starting caffeine was the first 24 HOL. In the overall comparisons, there was reduction in patent ductus arteriosus (OR 0.71 [0.55, 0. 92]; low evidence), retinopathy of prematurity (OR 0.71 [0.54, 0.93]; moderate evidence), severe brain injury (OR 0.79 [0.70, 0.91]; moderate evidence), bronchopulmonary dysplasia (BPD) (OR 0.69 [0.59, 0.81]; moderate evidence), composite outcome of BPD or death (OR 0.76 [0.66, 0.88]; moderate evidence). Mortality increase was found (OR 1.20 [1.12, 1.29], very low evidence).Caffeine in the first 24 HOL has benefits in reducing morbidities associated with prematurity. Mortality finding is potentially due to survival bias.

No difference in postprandial mesenteric blood flow between healthy younger and elderly individuals

We recently used phase-contrast magnetic resonance imaging (PC-MRI) to demonstrate an attenuated postprandial blood flow response in the superior mesenteric artery (SMA) in patients with Parkinson's disease compared to age- and sex-matched healthy controls. Since both groups showed substantial inter-individual variations, we extended the cohort of controls with a group of young individuals to investigate possible age-related effects. Seventeen healthy young subjects aged < 30 years and 17 elderly subjects aged > 50 years underwent serial PC-MRI to measure the postprandial blood flow response in the SMA after ingestion of a standardized liquid test meal (∼400 kcal). Postprandial blood flow dynamics in SMA did not differ between young and elderly subjects. A noticeable inter-individual variation in postprandial intestinal blood flow increase was found, and approximately 30% of the variation could be explained by the preprandial blood flow. Regardless of age, some subjects showed a remarkable transient SMA blood flow increase immediately after meal intake. This study provides tentative evidence that postprandial blood flow dynamics in SMA in healthy young and elderly subjects do not substantially differ, indicating that age is without impact on vascular response in SMA as an indicator for regulation of mesenteric perfusion in response to food intake.

Association of Caffeine Daily Dose With Respiratory Outcomes in Preterm Neonates: A Retrospective Cohort Study

Apnea and poor respiratory drive increase the risk of extubation failure (EF) and prolonged invasive mechanical ventilation (IMV) in preterm neonates (pre-nates) with respiratory distress. Caffeine citrate (CC) is often prescribed for pre-nates in doses of 5-10 mg/kg in 24 h. This study aimed to evaluate the most effective dosage regimen (5 mg/kg/day vs >5-10 mg/kg/day) to prevent apnea and EF with minimal caffeine-associated potential side effects (CC-APSEs) in pre-nates. This one-year retrospective cohort study included all the eligible neonates admitted to NICU and received CC-therapy till 28 days of life (DOL) or discharge. Based on CC-daily dose formed LD-caffeine-group (5 mg/kg/day) and HD-caffeine-group (>5-10 mg/kg/day). Antenatal, prenatal, and postnatal characteristics, CC-regimen, comorbidities, and CC-APSEs were compared between the groups. Predictors of apnea and EF were analyzed through logistic regression. There were 181 and 72 neonates in the LD and HD-caffeine-groups respectively. In HD-caffeine-group daily CC-dose was 7 to 7.5 mg/kg/day in 93% of neonates and >7.5 to 10 mg/kg/day in only 7%. Significantly fewer neonates experienced apnea and EF in the HD-caffeine-group till 28DOL or discharge. This difference was even greater in the subgroup of ≤28 weeks GA (15.6% vs 40.0%; P < .01). In HD-caffeine-group the incidence of severe/moderate-BPD was significantly lower and the frequency of CC-APSEs was higher. Multivariate analysis showed that; the smaller the GA higher the risk of apnea (AOR = 0.510, 95% CI 0.483-0.999) and EF (AOR = 0.787, 95% CI 0.411-0.997). The HD-caffeine was inversely associated with developing apnea (AOR = 0.244, 95% CI 0.053-0.291) and EF (AOR = 0.103, 95% CI 0.098-2.976). IMV-duration before extubation (AOR = 2.229, 95% CI 1.672-2.498) and severe/moderate-BPD (AOR = 2.410, 95%CI 1.104-2.952) had a high risk of EF. Initiating early HD-caffeine may prevent apnea and extubation failure in preterm neonates. Optimization of caffeine initiation time and dosages can be a safe and feasible approach to decrease the burden of neonatal respiratory morbidities.

A systematic review and meta-analysis of the role of Doppler ultrasonography of the superior mesenteric artery in detecting neonates at risk of necrotizing enterocolitis

The role of postnatal Doppler measurements of the superior mesenteric artery (SMA) in detecting neonates at risk of necrotizing enterocolitis (NEC) remains uncertain; therefore, we systematically reviewed and meta-analyzed the existing evidence regarding the usefulness of SMA Doppler measurements in detecting neonates at risk for NEC. We used the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, and we included studies which reported the following Doppler ultrasonography indices: peak systolic velocity, end-diastolic velocity, time average mean velocity, differential velocity, pulsatility index (PI) and resistive index. Eight studies were eligible for inclusion in the meta-analysis. Evidence suggested that, during the first postnatal day, neonates who developed NEC had a significantly higher peak systolic velocity (mean difference of 2.65 cm/s (95% confidence interval [CI] 1.23, 4.06, overall effect Z=3.66, P<0.001)), higher PI (mean difference of 1.52 (95% CI 0.00, 3.04, Z=1.96, P=0.05)) and higher resistive index (mean difference of 1.09 (95% CI 0.59, 1.60, Z=4.24, P<0.001)), compared to neonates who did not develop NEC. However, our findings do not support a strong association between the Doppler ultrasound indices and development of NEC at the time of disease onset. This meta-analysis suggests that first postnatal day SMA Doppler parameters, namely peak systolic velocity, PI and resistive index, are higher in neonates who develop NEC. On the other hand, the aforementioned indices are of uncertain significance once the diagnosis of NEC has been established.

Effects of Different Onset Times of Early Caffeine Treatment on Mesenteric Tissue Oxygenation and Necrotizing Enterocolitis: A Prospective, Randomized Study

OBJECTIVE

Caffeine treatment is routinely used in premature infants to prevent development of apnea and bronchopulmonary dysplasia. Although a limited number of studies have reported that early caffeine treatment may cause development of necrotizing enterocolitis (NEC) by reducing mesenteric blood flow, this issue is still under discussion. The aim of this study is to investigate the possible effect of different onset times of early caffeine treatment on mesenteric tissue oxygen saturation and NEC development in premature infants.

STUDY DESIGN

A total of 87 preterm infants with ≤1,250-g birth weight (BW) was included in this prospective study. The cases were randomized as group 1 (first 24 hours) and group 2 (72nd hour) caffeine treatment groups and monitored by near-infrared spectroscopy (NIRS) for 72 hours from the time of admission until cerebral, renal, and mesenteric tissue oxygen saturations (rSO₂) were recorded. The cases were followed-up to the 40th week in terms of NEC and other neonatal morbidities.

RESULTS

A total of 87 infants were included in the study, including 45 in group 1 and 42 in group 2. The groups were similar in terms of demographic characteristics. The incidence of NEC in group 1 (20%) was higher in comparison to group 2 (9%). The mesenteric rSO₂ values in the first 72 hours of group 1 were lower than those of group 2. Low gestational week, BW, and late onset of enteral feeding were found to be other significant risk factors for NEC.

CONCLUSION

In this study, mesenteric tissue oxygenation was lower, and NEC was higher in group 1. Mesenteric rSO₂ measurements may be useful in predicting the development of NEC in patients receiving early caffeine therapy.

KEY POINTS

· Onset time of early caffeine treatment may effect on mesenteric tissue oxygen saturation.. · Caffeine treatment that onset in the first 24 hours may be associated with NEC development.. · Mesenteric rSO2 measurements may be useful in patients receiving early caffeine therapy..

Precision caffeine therapy for apnea of prematurity and circadian rhythms: New possibilities open up

Caffeine is the globally consumed psychoactive substance and the drug of choice for the treatment of apnea of prematurity (AOP), but its therapeutic effects are highly variable among preterm infants. Many of the molecular underpinnings of the marked individual response have remained elusive yet. Interestingly, the significant association between Clock gene polymorphisms and the response to caffeine therapy offers an opportunity to advance our understanding of potential mechanistic pathways. In this review, we delineate the functions and mechanisms of human circadian rhythms. An up-to-date advance of the formation and ontogeny of human circadian rhythms during the perinatal period are concisely discussed. Specially, we summarize and discuss the characteristics of circadian rhythms in preterm infants. Second, we discuss the role of caffeine consumption on the circadian rhythms in animal models and human, especially in neonates and preterm infants. Finally, we postulate how circadian-based therapeutic initiatives could open new possibilities to promote precision caffeine therapy for the AOP management in preterm infants.

Effects of Caffeine on Splanchnic Oxygenation in Preterm Infants

OBJECTIVE

The aim of this study is to assess the effects of administering 20 mg/kg loading dose of caffeine citrate intravenously on splanchnic oxygenation in preterm infants.

STUDY DESIGN

The infants with a gestational age (GA) of <34 weeks who were administered with a 20 mg/kg intravenous loading dose of caffeine citrate within 48 hours after birth were investigated prospectively. Regional splanchnic oxygen saturation (rsSO₂) and splanchnic fractional tissue oxygen extraction rate (sFTOE) were measured using near-infrared spectroscopy before caffeine infusion, immediately after caffeine infusion and 1, 2, 3, 4, and 6 hours (h) after dose completion; postdose values were compared with predose values.

RESULTS

A total of 41 infants with a mean GA of 29.2 ± 1.6 weeks and birth weight of 1,315 ± 257 g as well as postnatal age of 32.2 ± 10.8 hours were included in the study. rsSO₂ significantly reduced from 63.1 to 57.5% immediately after caffeine infusion, 55.1% after 1 hour, and 55.2% after 2 hours with partial recovery at 3-hour postdose. sFTOE increased correspondingly.

CONCLUSION

Caffeine reduces splanchnic oxygenation and increases splanchnic oxygen extraction for at least 2 hours with partial recovery to predose levels at 3-hour postdose.

Prophylactic versus therapeutic caffeine for apnea of prematurity: a randomized controlled trial

BACKGROUND

Therapeutic initiation of methyxanthines for treatment of apnea in preterm infants was the standard policy. Caffeine therapy is beneficial for various outcomes of preterm infants.

AIM

To evaluate the efficacy of early prophylactic compared to routine therapeutic caffeine therapy on duration of oxygen support and other outcomes of preterm infants.

METHODS

In a randomized controlled trial including preterm infants < 32 weeks' gestation, prophylactic (in the first 72 h of life) versus therapeutic (only if apnea exists or infant requires mechanical ventilation) decision of caffeine was compared. The primary outcome was the duration of oxygen therapy. Secondary outcomes included duration of respiratory support modalities; bronchoplumonary dysplasia (BPD); necrotizing enterocolitis; intra-ventricular hemorrhage; retinopathy of prematurity; length of hospital stay (LOS); neonatal mortality; and caffeine side effects.

RESULTS

We enrolled 90 infants in the prophylactic and 91 infants in therapeutic groups respectively. Prophylactic caffeine decreased the duration of oxygen therapy [median and IQR of 28 (18-36) days versus 34 (23-51) days, p = .005 respectively]. Prophylactic caffeine significantly decreased the durations of respiratory support modalities, LOS, and incidences of mild to moderate BPD without reported effects on the incidence of severe BPD or other clinical outcomes compared to therapeutic caffeine. A significantly higher proportion of infants in the prophylactic caffeine group did not require mechanical ventilation during their NICU admission and a significant lower proportion required late mechanical ventilation compared to the prophylactic caffeine group.

CONCLUSION

Prophylactic caffeine decreased the duration of oxygen therapy, invasive and noninvasive ventilation, incidences of mild to moderate BPD, and LOS in preterm infants.

Doppler ultrasound assessment of splanchnic perfusion and heart rate for the detection of necrotizing enterocolitis

PURPOSE

Monitoring disease progression is crucial to improve the outcome of necrotizing enterocolitis (NEC). A previous study indicates that intestinal wall flow velocity was reduced in NEC pups from the initial stages of the disease. This study aims to investigate whether splanchnic perfusion via the superior mesenteric artery (SMA) (i) is altered during NEC development and (ii) can be used as a monitoring tool to assess disease progression.

METHODS

NEC was induced in C57BL/6 mice via gavage feeding of formula, hypoxia, and oral lipopolysaccharide, from postnatal day 5 (P5) to P9 (AUP: 32,238). Breastfed littermates served as controls. Doppler ultrasound (U/S) of bowel loops was performed daily. Intestinal wall perfusion was calculated as average flow velocity (mm/s) of multiple abdominal regions. Groups were compared using one-way ANOVA.

RESULTS

The SMA flow velocity was not altered during the initial stage of NEC development, but become significantly reduced at P8 when the intestinal disease was more advanced. These changes occurred concomitantly with an increase in heart rate.

CONCLUSIONS

NEC is associated with intestinal hypo-perfusion at the periphery and flow in the SMA is reduced during the later stages of disease indicating the presence of intestinal epithelium damage. This study contributes to understanding NEC pathophysiology and illustrates the value of Doppler U/S in monitoring disease progression.

When to start and stop caffeine and why respiratory status matters

Caffeine as tested in the CAP trial is safe and effective for preterm infants with birthweights less than 1250 g. Evidence for its use beyond the indications and timing used in this trial is of low quality and conflicting. Some studies suggest that earlier use of caffeine increases the risk of mortality while others suggest it has important benefits. It appears that infants with apnea of prematurity and those receiving assisted ventilation are the most likely to benefit from caffeine. Based on currently available evidence, routine early prescription of caffeine does not appear to be indicated. Infants continue to have potentially damaging episodes of hypoxia secondary to apnea beyond 34 weeks' postmenstrual age. It is unclear whether prolonged use of caffeine improves outcomes in these infants. Randomized trials to resolve these uncertainties are required. They need to be large, at least the size of the CAP trial, and include neurodevelopmental outcomes.

Early Doppler Ultrasound in the Superior Mesenteric Artery and the Prediction of Necrotizing Enterocolitis in Preterm Neonates

OBJECTIVES

The purpose of this study was to reveal the correlation between superior mesenteric artery (SMA) blood flow in the first 12 hours of life and the risk of necrotizing enterocolitis (NEC) in preterm neonates.

METHODS

We conducted a prospective study. There were 104 preterm neonates included in our study. The SMA blood flow of each neonate was measured during the first 12 hours of life if the hemodynamic situation was stable. The results of Doppler ultrasound were confidential to the neonatologists and nurses. All of the demographics, comorbidities, and outcomes were recorded and analyzed.

RESULTS

Among all of the demographics and comorbidities, the gestational age was related to the measurements of SMA blood flow. We conducted a single-factor analysis of the occurrence of NEC, including the peak systolic velocity (PSV), end-diastolic velocity, time-averaged mean velocity, differential velocity (DV), resistive index, and pulsatility index. A higher PSV (median [interquartile range], 54.165 [42.423-68.463] versus 42.195 [34.278-48.553] cm/s; P = .027) and DV (median [interquartile range], 47.445 [35.010-60.043] versus 32.565 [27.545-39.073] cm/s; P = .020) were significantly related to the risk of NEC. In the logistic analysis including gestational age, PSV, and DV, NEC was significantly associated with gestational age (odds ratio [95% confidence interval], 0.644 [0.456-0.908]; P = .012) and DV (odds ratio [95% confidence interval], 1.144 [1.058-1.237]; P < .01). The area under the receiver operating characteristic curve for the DV was 0.768, with sensitivity 0.875 and specificity 0.604. The cutoff value of the DV was 34.835 cm/s.

CONCLUSIONS

From this single-center study, we can see the promising value of Doppler ultrasound for the prediction of NEC, but further research is needed.