Radiation Doses to the Entire Catheterization Laboratory Team With a Novel Radiation Protection Device.

Background: A novel radiation protection system has recently been shown to shield the primary operator from scatter radiation, but whether it shields other members of the catheterization laboratory team remains unknown. Methods: Radiation exposure data were collected prospectively in 50 coronary angiography cases, in which 25 were completed using standard radiation protection and 25 with a novel system consisting of a series of rigid shields and flexible radiation-resistant drapes. Radiation doses, measured with real-time dosimeters, were compared between the 2 groups. Results: There were no significant differences between groups with respect to patient or procedural characteristics, including air kerma (P = .97) and dose area product (P = .17). The primary operator received a median head-level radiation dose of 0.0 [0.0, 0.0] µSv with the novel radiation protection system and 2.1 [0.7, 3.3] µSv with standard radiation protection (P < .001). Scrub technologists had a median head-level radiation dose of 0.0 [0.0, 0.0] µSv with the novel radiation protection system and 0.3 [0.1, 0.4] µSv with standard radiation protection (P < .001). The median head-level radiation dose among circulating nurses was 0.0 [0.0, 0.0] µSv with the novel radiation protection system and was 0.1 [0.0, 0.2] µSv with standard radiation protection (P < .001). Conclusions: Compared to standard radiation protection with lead aprons, use of a novel radiation protection system during coronary angiography was associated with significantly lower head-level radiation doses among all members of the catheterization laboratory team.

Treatment Adherence Rates and Long-Term Mortality in a Quaternary Multidisciplinary Heart Team: An Observational Cohort.

BACKGROUND: A multidisciplinary heart team (HT) approach to patients with complex coronary artery disease has a class IB recommendation, yet there are limited data on adherence to HT treatment recommendations and long-term clinical follow-up. The objective of this study was to assess adherence rates to HT recommendations and assess long-term mortality rates among patients with complex CAD. METHODS AND RESULTS: Six hundred eighty-four sequential HT cases for complex coronary artery disease from January 2015 to May 2017 were reviewed. After excluding cases with significant comorbid valve disease, baseline characteristics were compared based on HT treatment recommendations: optimal medical therapy, percutaneous coronary intervention, and coronary artery bypass grafting. Adherence rates were manually extracted, and 5-year mortality rates were obtained from the Michigan Death Registry. Seventy-two percent of 405 included patients were men (mean age 66±11 years), with high rates of medical comorbidities. Estimated surgical risk scores were lowest in the coronary artery bypass grafting group. Optimal medical therapy was recommended in 138 patients (34%), percutaneous coronary intervention in 95 (23%), and coronary artery bypass grafting in 172 (42%). Adherence to HT recommendations across groups was high (96%) and did not differ between treatment groups. Over 5 years of follow-up, there were 119 deaths, resulting in a cumulative mortality rate of 29%. CONCLUSIONS: In the largest HT cohort in the United States to date, high rates of adherence to HT recommendations were observed among high-risk patients with coronary artery disease. High rates of adherence to HT recommendations were observed irrespective of treatment group recommendation, suggesting that HT recommendations were individualized and acceptable to both patients and physicians alike.

Four-year follow-up of outcomes of the hybrid epicardial-endocardial ablation: A single-center experience.

BACKGROUND: The CONVERGE trial demonstrated that hybrid epicardial and endocardial ablation was more effective than catheter ablation for the treatment of persistent atrial fibrillation (AF) at 1 year. Long-term real-world outcome data are scarce. OBJECTIVE: We described a single-center experience by evaluating the long-term effectiveness and safety of hybrid epicardial-endocardial ablation. METHODS: This is a retrospective single-center study. Patients were followed up to 4 years. The primary end point was the rate of AF recurrence up to 4 years postablation. Secondary end points included reduction in antiarrhythmic therapy use, the effect of the ligament of Marshall removal, epicardial posterior wall, 3-dimensional mapping during epicardial ablation, and left atrial appendage exclusion as adjunct intraoperative interventions for AF recurrence. RESULTS: Of the 170 patients, 86.5% had persistent AF and 13.5% had long-standing persistent AF. AF-free survival was 87.6% at 1 year, 76.9% at 2 years, 70.4% at 3 years, and 59.3% at 4 years. Antiarrhythmic drug use was 87.6% at baseline and reduced to 21%, 20.6%, 18%, and 14.1% at year 1, 2, 3, and 4, respectively (P < .01 for all). Three-dimensional epicardial mapping showed a significant reduction in combined recurrence from 42% to 25% over 4 years of follow-up (P = .023). Ligament of Marshall and left atrial appendage exclusion showed numerical reduction in AF recurrence from 35% to 26% (P = .49) and from 44% to 30% (P = .07). CONCLUSION: The hybrid convergent procedure reduces AF recurrence and the need for antiarrhythmic drugs and, while maintaining a good safety profile, for the treatment of persistent and long-standing persistent AF.

START CARE: a protocol for a randomised controlled trial of step-wise budesonide-formoterol reliever-based treatment in children.

Background: Asthma is the most common chronic childhood respiratory condition globally. Inhaled corticosteroid (ICS)-formoterol reliever-based regimens reduce the risk of asthma exacerbations compared with conventional short-acting ß2-agonist (SABA) reliever-based regimens in adults and adolescents. The current limited evidence for anti-inflammatory reliever therapy in children means it is unknown whether these findings are also applicable to children. High-quality randomised controlled trials (RCTs) are needed. Objective: The study aim is to determine the efficacy and safety of budesonide-formoterol reliever alone or maintenance and reliever therapy (MART) compared with standard therapy: budesonide or budesonide-formoterol maintenance, both with terbutaline reliever, in children aged 5 to 11 years with mild, moderate and severe asthma. Methods: A 52-week, multicentre, open-label, parallel group, phase III, two-sided superiority RCT will recruit 400 children aged 5 to 11 years with asthma. Participants will be randomised 1:1 to either budesonide-formoterol 100/6 µg Turbuhaler reliever alone or MART; or budesonide or budesonide-formoterol Turbuhaler maintenance, with terbutaline Turbuhaler reliever. The primary outcome is moderate and severe asthma exacerbations as rate per participant per year. Secondary outcomes are asthma control, lung function, exhaled nitric oxide and treatment step change. Assessment of Turbuhaler technique and cost-effectiveness analysis are also planned. Conclusion: This will be the first RCT to compare the efficacy and safety of a step-wise budesonide-formoterol reliever alone or MART regimen with conventional inhaled ICS or ICS-long-acting ß-agonist maintenance plus SABA reliever in children. The results will provide a much-needed evidence base for the treatment of asthma in children.

COVID-19 Viral Infection Presenting With Diabetic Ketoacidosis, Hyperosmolar Hyperglycemic Syndrome, or Mixed Hyperglycemic Crisis: A Case Series.

Cardiovascular disease, COPD, and diabetes (DM) are associated with increased complications with COVID-19. A correlation between COVID-19 and diabetic ketoacidosis (DKA) or Hyperosmolar Hyperglycemic Syndrome (HHS) has been suggested; however, the precise mechanism remains unclear. We present a case series of six patients with COVID-19 infections who were found to have DKA, HHS, or mixed picture. Wedescribe an association between COVID-19 and hyperglycemic emergencies. Six patients (50% male, 50% female, mean age 47.667 ± 18.747) were identified from November 2021 to February 2022. Comorbidities included DM (83.3%), HTN (50%), as well as ESRD, A-Fib, ISLD, HIV, and dementia (each 16.7%). Common review of systems included nausea and vomiting (50%), abdominal pain (33.3%), dyspnea (33.3%), and decreased appetite (33.3%). Additional findings were dysarthria, facial droop, generalized weakness, productive cough, myalgias, and increased urinary frequency (16.7%). Patients were diagnosed with DKA (50%), mixed process (33.3%), andHHS(16.7%). In terms of COVID-19 symptoms, most patients were asymptomatic (83.3%), with one patient developing hypoxia. The survival rate was 100%. Infections can incite DKA/HHS; yet, COVID-19 may have factors that amplify this process, in the setting of pancreatic beta-cell dysfunction from the virus itself. This may contribute to why diabetic patients have a ten times higher risk of death if they develop COVID-19. This virus binds to ACE2 receptors in the pancreas and damages the islets, ultimately decreasing insulin release. Here, we introduce cases of DKA/HHS in the setting of COVID-19, to understand the relationship between how COVID-19 infections may exacerbate diabetic complications.

Physician Radiation Exposure During Endomyocardial Biopsy and Right Heart Catheterization.

BACKGROUND: Cardiologists performing coronary angiography (CA) and percutaneous coronary intervention (PCI) are at risk of health problems related to chronic occupational radiation exposure. Unlike during CA and PCI, physician radiation exposure during right heart catheterization (RHC) and endomyocardial biopsy (EMB) has not been adequately studied. The objective of this study was to assess physicians' radiation doses during RHC with and without EMB and compare them to those of CA and PCI. METHODS: Procedural head-level physician radiation doses were collected by real-time dosimeters. Radiation-dose metrics (fluoroscopy time, air kerma [AK] and dose area product [DAP]), and physician-level radiation doses were compared among RHC, RHC with EMB, CA, and PCI. RESULTS: Included in the study were 351 cardiac catheterization procedures. Of these, 36 (10.3%) were RHC, 42 (12%) RHC with EMB, 156 (44.4%) CA, and 117 (33.3%) PCI. RHC with EMB and CA had similar fluoroscopy time. AK and DAP were progressively higher for RHC, RHC with EMB, CA, and PCI. Head-level physician radiation doses were similar for RHC with EMB vs CA (P = 0.07). When physicians' radiation doses were normalized to DAP, RHC and RHC with EMB had the highest doses. CONCLUSION: Physicians' head-level radiation doses during RHC with EMB were similar to those of CA. After normalizing to DAP, RHC and RHC with EMB were associated with significantly higher physician radiation doses than CA or PCI. These observations suggest that additional protective measures should be undertaken to decrease physicians' radiation exposure during RHC and, in particular, RHC with EMB.

Caffeine to prevent intermittent hypoxaemia in late preterm infants: randomised controlled dosage trial.

OBJECTIVE: To establish the most effective and best tolerated dose of caffeine citrate for the prevention of intermittent hypoxaemia (IH) in late preterm infants. DESIGN: Phase IIB, double-blind, five-arm, parallel, randomised controlled trial. SETTING: Neonatal units and postnatal wards of two tertiary maternity hospitals in New Zealand. PARTICIPANTS: Late preterm infants born at 34+0-36+6 weeks' gestation, recruited within 72 hours of birth. INTERVENTION: Infants were randomly assigned to receive a loading dose (10, 20, 30 or 40 mg/kg) followed by 5, 10, 15 or 20 mg/kg/day equivolume enteral caffeine citrate or placebo daily until term corrected age. PRIMARY OUTCOME: IH (events/hour with oxygen saturation concentration ≥10% below baseline for ≤2 min), 2 weeks postrandomisation. RESULTS: 132 infants with mean (SD) birth weight 2561 (481) g and gestational age 35.7 (0.8) weeks were randomised (24-28 per group). Caffeine reduced the rate of IH at 2 weeks postrandomisation (geometric mean (GM): 4.6, 4.6, 2.0, 3.8 and 1.7 events/hour for placebo, 5, 10, 15 and 20 mg/kg/day, respectively), with differences statistically significant for 10 mg/kg/day (GM ratio (95% CI] 0.39 (0.20 to 0.76]; p=0.006) and 20 mg/kg/day (GM ratio (95% CI] 0.33 (0.17 to 0.68]; p=0.003) compared with placebo. The 20 mg/kg/day dose increased mean (SD) pulse oximetry oxygen saturation (SpO2) (97.2 (1.0) vs placebo 96.0 (0.8); p<0.001), and reduced median (IQR) percentage of time SpO2 <90% (0.5 (0.2-0.8) vs 1.1 (0.6-2.4); p<0.001) at 2 weeks, without significant adverse effects on growth velocity or sleeping. CONCLUSION: Caffeine reduces IH in late preterm infants at 2 weeks of age, with 20 mg/kg/day being the most effective dose. TRIAL REGISTRATION NUMBER: ACTRN12618001745235.

Comparison of Radiation Exposure Among Interventional Echocardiographers, Interventional Cardiologists, and Sonographers During Percutaneous Structural Heart Interventions.

Importance: Transesophageal echocardiography during percutaneous left atrial appendage closure (LAAO) and transcatheter edge-to-edge mitral valve repair (TEER) require an interventional echocardiographer to stand near the radiation source and patient, the primary source of scatter radiation. Despite previous work demonstrating high radiation exposure for interventional cardiologists performing percutaneous coronary and structural heart interventions, similar data for interventional echocardiographers are lacking. Objective: To assess whether interventional echocardiographers are exposed to greater radiation doses than interventional cardiologists and sonographers during structural heart procedures. Design, Setting, and Participants: In this single-center cross-sectional study, radiation doses were collected from interventional echocardiographers, interventional cardiologists, and sonographers at a quaternary care center during 30 sequential LAAO and 30 sequential TEER procedures from July 1, 2016, to January 31, 2018. Participants and study personnel were blinded to radiation doses through data analysis (January 1, 2020, to October 12, 2021). Exposures: Occupation defined as interventional echocardiographers, interventional cardiologists, and sonographers. Main Outcomes and Measures: Measured personal dose equivalents per case were recorded using real-time radiation dosimeters. Results: A total of 60 (30 TEER and 30 LAAO) procedures were performed in 60 patients (mean [SD] age, 79 [8] years; 32 [53.3%] male) with a high cardiovascular risk factor burden. The median radiation dose per case was higher for interventional echocardiographers (10.6 µSv; IQR, 4.2-22.4 µSv) than for interventional cardiologists (2.1 µSv; IQR, 0.2-8.3 µSv; P < .001). During TEER, interventional echocardiographers received a median radiation dose of 10.5 µSv (IQR, 3.1-20.5 µSv), which was higher than the median radiation dose received by interventional cardiologists (0.9 µSv; IQR, 0.1-12.2 µSv; P < .001). During LAAO procedures, the median radiation dose was 10.6 µSv (IQR, 5.8-24.1 µSv) among interventional echocardiographers and 3.5 (IQR, 1.3-6.3 µSv) among interventional cardiologists (P < .001). Compared with interventional echocardiographers, sonographers exhibited low median radiation doses during both LAAO (0.2 µSv; IQR, 0.0-1.6 µSv; P < .001) and TEER (0.0 µSv; IQR, 0.0-0.1 µSv; P < .001). Conclusions and Relevance: In this cross-sectional study, interventional echocardiographers were exposed to higher radiation doses than interventional cardiologists during LAAO and TEER procedures, whereas sonographers demonstrated comparatively lower radiation doses. Higher radiation doses indicate a previously underappreciated occupational risk faced by interventional echocardiographers, which has implications for the rapidly expanding structural heart team.

Robotically performed diagnostic coronary angiography.

OBJECTIVE: This study was performed to investigate the efficacy and safety of robotic diagnostic coronary angiography. BACKGROUND: Robotic percutaneous coronary intervention is associated with marked reductions in physician radiation exposure. Development of robotic diagnostic coronary angiography might similarly impact occupational safety. METHODS: Stable patients referred for coronary angiography were prospectively enrolled. After obtaining vascular access, diagnostic catheters were manually advanced over a wire to the ascending aorta. All subsequent catheter movements were performed robotically. The primary endpoint was procedural success, defined as robotic completion of coronary angiography without conversion to a manual procedure and the absence of procedural major adverse cardiovascular events (MACE-cardiac death, cardiac arrest, or stroke) and major angiographic complications (coronary/aortic dissection or embolization). The primary hypothesis was that the observed rate of the primary endpoint, evaluated at the completion of coronary angiography, would meet a pre-specified performance goal of 74.5%. RESULTS: Among 46 consecutive patients (age 67 ± 12 years; 69.6% male), diagnostic coronary angiography was completed robotically in all cases without the need for manual conversion and without any MACE or major angiographic complications. Thus, procedural success was 100%, which was significantly higher than the pre-specified performance goal (p < 0.001). Robotic coronary angiography was completed using 2 [2, 3] catheters per case with a median procedural time of 15 [11, 20] minutes. CONCLUSIONS: Robotic diagnostic coronary angiography was performed with 100% procedural success and no observed complications. These results support the performance of future studies to further explore robotic coronary angiography.

Pandemic-Associated Delays in Myocardial Infarction Presentation in Predominantly Rural Counties With Low COVID-19 Prevalence.

Fewer ST-elevation myocardial infarctions (STEMIs) presentations and increased delays in care occurred during the COVID-19 pandemic in urban areas. Whether these associations occurred in a more rural population has not been previously reported. Our objective was to evaluate the impact of COVID-19 on time-to-presentation for STEMI in rural locations. Patients presenting to a large STEMI network spanning 27 facilities and 13 predominantly rural counties between January 1, 2016 and April 30, 2020 were included. Presentation delays, defined as time from symptom onset to arrival at the first medical facility, classified as ≥12 and ≥24 hours from symptom onset were compared among patients in the pre-COVID-19 and the early COVID-19 eras. To account for patient-level differences, 2:1 propensity score matching was performed using binary logistic regression. Among 1,286 patients with STEMI, 1,245 patients presented in the pre-COVID-19 era and 41 presented during the early COVID-19 era. Presentation delays ≥12 hours (19.5% vs 4.0%) and ≥24 hours (14.6% and 0.2%) were more common in COVID-19 than pre-COVID-19 cohorts (p <0.001 for both), despite a low COVID-19 prevalence. Similar results were seen in propensity-matched comparisons (≥12 hours: 19.5% vs 2.4%, p = 0.002; ≥24 hours 14.6% vs 0.0%, p = 0.001). In a predominantly rural STEMI population, delays in seeking medical care after symptom onset were markedly more frequent during the COVID-19 era, despite low COVID-19 prevalence. Considering delays in reperfusion have multiple adverse downstream consequences, these findings may have important implications in rural communities during future pandemic resurgences.

Suspended lead suit and physician radiation doses during coronary angiography.

OBJECTIVE: This study was performed to evaluate physician radiation doses with the use of a suspended lead suit. BACKGROUND: Interventional cardiologists face substantial occupational risks from chronic radiation exposure and wearing heavy lead aprons. METHODS: Head-level physician radiation doses, collected using real-time dosimeters during consecutive coronary angiography procedures, were compared with the use of a suspended lead suit versus conventional lead aprons. Multiple linear regression analyses were completed using physician radiation doses as the response and testing patient variables (body mass index, age, sex), procedural variables (right heart catheterization, fractional flow reserve, percutaneous coronary intervention, radial access), and shielding variables (radiation-absorbing pad, accessory lead shield, suspended lead suit) as the predictors. RESULTS: Among 1054 coronary angiography procedures, 691 (65.6%) were performed with a suspended lead suit and 363 (34.4%) with lead aprons. There was no significant difference in dose area product between groups (61.7 [41.0, 94.9] mGy·cm2 vs. 64.6 [42.9, 96.9] mGy·cm2 , p = 0.20). Median head-level physician radiation doses were 10.2 [3.2, 35.5] µSv with lead aprons and 0.2 [0.1, 0.9] µSv with a suspended lead suit (p < 0.001), representing a 98.0% reduced dose with suspended lead. In the fully adjusted regression model, the use of a suspended lead suit was independently associated with a 93.8% reduction (95% confidence interval: -95.0, -92.3; p < 0.001) in physician radiation dose. CONCLUSION: Compared to conventional lead aprons, the use of a suspended lead suit during coronary angiography was associated with marked reductions in head-level physician radiation doses.

The Children's Anti-inflammatory Reliever (CARE) study: a protocol for a randomised controlled trial of budesonide-formoterol as sole reliever therapy in children with mild asthma.

BACKGROUND: Asthma is the most common chronic disease in children, many of whom are managed solely with a short-acting ß2-agonist (SABA). In adults, the evidence that budesonide-formoterol as sole reliever therapy markedly reduces the risk of severe exacerbations compared with SABA alone has contributed to the Global Initiative for Asthma recommending against SABA monotherapy in this population. The current lack of evidence in children means it is unknown whether these findings are also relevant to this demographic. High-quality randomised controlled trials (RCTs) are needed. OBJECTIVE: The aim of this study is to determine the efficacy and safety of as-needed budesonide-formoterol therapy compared with as-needed salbutamol in children aged 5 to 15 years with mild asthma, who only use a SABA. METHODS: A 52-week, open-label, parallel group, phase III RCT will recruit 380 children aged 5 to 15 years with mild asthma. Participants will be randomised 1:1 to either budesonide-formoterol (Symbicort Rapihaler®) 50/3 µg, two actuations as needed, or salbutamol (Ventolin®) 100  µg, two actuations as needed. The primary outcome is asthma attacks as rate per participant per year. Secondary outcomes assess asthma control, lung function, exhaled nitric oxide and treatment step change. A cost-effectiveness analysis is also planned. CONCLUSION: This is the first RCT to assess the safety and efficacy of as-needed budesonide-formoterol in children with mild asthma. The results will provide a much-needed evidence base for the treatment of mild asthma in children.

Relations Between Cardiac Magnetic Resonance Imaging-Derived Left Ventricular Mass, Early Repolarization, and Cardiovascular Events (from the Dallas Heart Study).

Early repolarization pattern (ERP) is associated with increased mortality in case-control studies, but the mechanism and role of left ventricular mass (LVM) remain unclear. Our objectives were to understand (1) whether ERP associates with adverse outcomes in a multiethnic population and (2) to explore the role of LVM in these associations. Participants from the Dallas Heart Study with an electrocardiogram interpretable for ERP, defined as J point elevation ≥1 mm in 2 contiguous leads, were included. Combined all-cause mortality and nonfatal cardiovascular disease (CVD) events and individual components were assessed using Cox proportional hazards modeling after adjustment for demographics, traditional CVD risk factors, electrocardiogram intervals, and cardiac magnetic resonance imaging-derived factors. Cardiac magnetic resonance imaging-defined LVM was then added to the most fully adjusted model. Of the 2,686 participants, 240 (8.9%) demonstrated ERP. Participants with ERP were more likely to be male and Black, with lower body mass index, greater left ventricular end-diastolic volumes, and LVM. Over a median follow-up of 11 years, the combined end point occurred in 326 patients. Multivariable modeling demonstrated ERP was associated with the combined end point (HR [95% CI] 1.61 [1.14 to 2.26]), all-cause mortality (1.67 [1.00 to 2.80]). However, further adjusting for LVM attenuated the associations of ERP with the primary end point (HR [95% CI] 1.22 [0.85 to 1.77]) and secondary end points of mortality (1.39 [0.80 to 2.41]) and nonfatal CVD (1.05 [0.68 to 1.64]). ERP was associated with increased mortality and nonfatal CVD events, which was attenuated after adjusting for LVM, a previously under-recognized clinical phenotype. Previous associations of ERP with adverse cardiovascular outcomes may be partially explained by greater LVM in those with ERP.

Impact of oral corticosteroids on respiratory outcomes in acute preschool wheeze: a randomised clinical trial.

OBJECTIVE: To determine if administration of oral prednisolone to preschool children with acute wheeze alters respiratory outcomes. DESIGN: Double-blind, randomised, placebo-controlled equivalence trial. SETTING: Three hospitals in New Zealand. PATIENTS: 477 children aged 24-59 months with acute wheeze associated with respiratory illness. INTERVENTIONS: 2 mg/kg (maximum 40 mg) oral prednisolone or similar placebo, once daily for 3 days. MAIN OUTCOME MEASURES: Primary outcome was change in Preschool Respiratory Assessment Measure (PRAM) score 24 hours after intervention. Secondary outcomes included PRAM score at 4 hours, length of emergency department and inpatient stays, admission and representation rates, time to return to normal activities and use of additional oral prednisolone or intravenous medications. Analysis was by intention-to-treat. RESULTS: There was no difference between groups for change in PRAM score at 24 hours (difference between means -0.39, 95% CI -0.84 to 0.06, p=0.09). Absolute PRAM score was lower in the prednisolone group at 4 hours (median (IQR) 1 (0-2) vs 2 (0-3), p=0.01) and 24 hours (0 (0-1) vs 0 (0-1), p=0.01), when symptoms had resolved for most children regardless of initial treatment. Admission rate, requirement for additional oral prednisolone and use of intravenous medication were lower in the prednisolone group, although there were no differences between groups for time taken to return to normal activities or rates of representation within 7 days. CONCLUSION: Oral prednisolone does not alter respiratory outcomes at 24 hours or beyond in preschool children presenting with acute wheeze.

(Rad 8)Caffeine prophylaxis to improve intermittent hypoxaemia in infants born late preterm: a randomised controlled dosage trial (Latte Dosage Trial).

INTRODUCTION: Infants born late preterm (34+0 to 36+6 weeks' gestational age) have frequent episodes of intermittent hypoxaemia compared with term infants. Caffeine citrate reduces apnoea and intermittent hypoxaemia and improves long-term neurodevelopmental outcomes in infants born very preterm and may have similar effects in late preterm infants. Clearance of caffeine citrate increases with gestational age and late preterm infants are likely to need a higher dose than very preterm infants. Our aim is to determine the most effective and best-tolerated dose of caffeine citrate to reduce transient intermittent hypoxaemia events in late preterm infants. METHODS AND ANALYSIS: A phase IIB, double-blind, five-arm, parallel, randomised controlled trial to compare the effect of four doses of oral caffeine citrate versus placebo on the frequency of intermittent hypoxaemia. Late preterm infants will be enrolled within 72 hours of birth and randomised to receive 5, 10, 15 or 20 mg/kg/day caffeine citrate or matching placebo daily until term corrected age. The frequency of intermittent hypoxaemia (events/hour where oxygen saturation concentration is ≥10% below baseline for ≤2 min) will be assessed with overnight oximetry at baseline, 2 weeks after randomisation (primary outcome) and at term corrected age. Growth will be measured at these timepoints, and effects on feeding and sleeping will be assessed by parental report. Data will be analysed using generalised linear mixed models. ETHICS AND DISSEMINATION: This trial has been approved by the Health and Disability Ethics Committees of New Zealand (reference 18/NTA/129) and the local institutional research review committees. Findings will be disseminated to peer-reviewed journals to clinicians and researchers at local and international conferences and to the public. The findings of the trial will inform the design of a large multicentre trial of prophylactic caffeine in late preterm infants, by indicating the most appropriate dose to use and providing information on feasibility. TRIAL REGISTRATION NUMBER: ACTRN12618001745235; Pre-results.