Rwanda has 55 public hospitals, which include eight referral hospitals, four provincial hospitals, four specialized hospitals, and 40 district hospitals. District hospitals offer comprehensive medical care, including general surgery, cesarean sections, and both inpatient and outpatient services, alongside laboratory diagnostics. They are primarily staffed by general physicians, nurses, midwives, and allied health professionals. Provincial hospitals are larger and better equipped than district hospitals, they serve as referral centers for their provinces, offering advanced healthcare services that district hospitals cannot provide. They provide a wider range of services, including internal medicine, pediatrics, and specialized care like ophthalmology and psychiatry. Additionally, they serve as referral centers for their provinces, offering advanced healthcare services that district hospitals cannot provide. Referral hospitals, on the other hand, provide more advanced specialized services such as intensive care, complex surgeries, organ transplants, and educational opportunities. These facilities are staffed by specialists, along with nurses and allied professionals. Specialized hospitals serve as national referral centers for specific clinical and paraclinical needs, drawing patients from across the country. They provide advanced, tailored care that general hospitals might not offer, focusing on managing non-acute conditions such as orthopedics, psychiatry, and physiotherapy.

Health facilities typically have several wards, and depending on a patient's medical conditions, a patient may be moved between different wards during treatment. The emergency ward delivers care for acute and urgent conditions affecting both adults and children, focusing on initial stabilization before transferring patients to their specific ward for further treatment. The maternity wards provide comprehensive care for pregnant women throughout antenatal, labor, delivery, and the postpartum period, addressing both vaginal and cesarean births, as well as any other pregnancy-related concerns and services. The surgery ward offers surgical procedures and post-operative care, including referrals from other facilities. The pediatric ward caters to children aged 28 days to 15 years with various medical issues, including subspecialties like pediatric oncology and cardiology. The internal medicine ward manages adult patients with non-surgical conditions, while the gynecology ward addresses non-urgent health concerns for women and adolescent girls. In the neonatology ward, care is provided for newborns up to 28 days old. The operating theatre ward cares for patients during their surgical procedures and transfers them to the recovery unit for immediate close monitoring. Once their condition is stable, they are then moved to the surgical ward for continued care. The intensive care unit delivers advanced support for critically ill patients, including mechanical ventilation and advanced medication dosage and infusion. Non-acute inpatient wards include physiotherapy where patients are supported to regain mobility after injury or surgery and includes prosthetics, orthotics, and orthopedics services. Lastly, the mental health ward offers care for individuals with psychiatric disorders and related conditions

In the retrospective cohort, 5766 patients were admitted on the sample frame days and had patient records from which to collect data. Of the original sample, 39/40 (97.5%) of facilities were included in the retrospective patient cohort study, one facility was not accessible to participate due to data access policy restrictions. In the healthcare worker survey conducted in all 40 hospitals, 1180 (91.3%) of participants consented to participate out of 1292 eligible to undertake the survey.

Pulse oximetry on admission was frequent, with 87.7% of patients (5025/5731, 95% CI 86.8–88.5%) with SpO₂ documented on admission (Table 3). It was most frequently documented in neonates, in 96.4% of neonates (585/607, 95% CI 94.6–97.6%), followed closely by pediatric patients at 90.0% (875/972, 95% CI 88.0-91.8%), and 85.9% of adults (3169/3714, 95% CI 84.2–86.4%).

A higher proportion of male patients had pulse oximetry documented on day of admission, 91.6% (1854/2023, 95% CI 90.4–92.8%), compared to 85.5% (3169/3706, 95% CI 84.3–86.6%) of female patients. However, excluding adult women admitted to maternity, the usage was more equal at 91.6% for men (1854/2022) and 91.9% for women (1821/1981).

Pulse oximetry usage on admission varied across different hospital wards, with some wards such as Neonatology screening 96.5% (572/593, 95% CI 94.6–97.7%) of patients on admission, and in pediatric units having SpO₂ documented in 95.2% of patients (335/352, 95% CI 92.4–97.0%). There were lower pulse oximetry practices on admission in patients admitted to maternity (78.9%, 1515/1921, CI 95% 77.0-80.6%).

Provincial and referral/university hospitals showed the highest pulse oximetry on admission at 97.8% (224/229, 95% CI 94.9–99.1%) and 91.5% (783/856, 95% CI 89.4–93.2%), respectively, followed by district hospitals 87.4% (3952/4520, 95% CI 86.4–88.4%) and patients admitted to specialized hospitals had the lowest pulse oximetry usage on admission, at 30.5% (25/82, 95% CI 21.5–41.2%).

Examining pulse oximetry usage across the course of the admission, on day of admission (Day 0), 87.7% of patients (5025/5731, 95% CI 86.8–88.5%) received pulse oximetry. Of 4919 patients that had a following day of admission (Day 1), 75.3% had a record of an SpO₂ measurement on this day (3702/4919, 95% CI 74.0-76.5%). Of the 4203 patients with longer admissions, 75.8% (3186/4203, 95% CI 74.5–77.1%) had an SpO₂ measurement in the remaining time from Day 2 until end of admission (Fig. 1).

By age group, adult women admitted to maternity had lower documentation of pulse oximetry overall and a steeper reduction in subsequent days of admission to just 54.9% (625/1139, 95% CI 52.0-57.7%), whilst neonates were measured on multiple days of admission with little decline in measurement (Table 4) – at 92.6% receiving a measurement between Day 2 to the end of admission (476/514, CI 95% 90.0 = 94.6%).

Out of 5025 patients who had pulse oximetry documented on day of admission, around 1 in 10 had severe hypoxemia (SpO₂ < 90%), (9.4%, 472/5025, 95% CI 8.6–10.2%), with variability across demographic and clinical categories (Table 3). Just over a quarter of neonates had documented hypoxemia, (27.9%, 163/585, 95% CI 24.4–31.6%), followed by 12.3% of pediatric patients (108/875, 95% CI 10.3–14.7%), and 5.7% of adults (180/3169, 4.9–6.5%). Excluding adult women admitted to maternity, an increased proportion, 9.6% of adults (175/1821) were documented to be severely hypoxemic on admission.

Hypoxemia was most commonly found in patients presenting with respiratory symptoms such as cough, in 40.5%, 38.6%, 50.0% of neonates, pediatric and adult patients experiencing cough, respectively (Table 5).

Most of the 472 hypoxemic patients, 92.2%, had oxygen therapy documented on the same day (441/472, 95% CI 90.8–95.4%). High coverage was found across all age groups from 97.5% of neonates (159/163, 95% CI 93.6–99.1%) to 90.6% of adults (163/180, 95% CI 85.3–94.1).

In the cohort overall, a total of 740 patients were prescribed oxygen, meaning about half of patients receiving oxygen on admission had documented severe hypoxemia (SpO₂ < 90%) (364/740, 49.2%). In the remaining group, 20.9% had moderate hypoxemia with an SpO₂ of 90–93%, 28.1% had a normal SpO₂ of 94–100%, and 1.8% with no pulse oximetry measurement documented.

Inpatient mortality was 10.9% in neonates (66/607, 95% CI 8.6–13.6%), whilst older pediatrics (29 days – 14 years) had a 1.2% mortality rate (12/972, 95% CI 0.7–2.2%). Excluding women admitted to maternity, 4.9% of adults died during admission (97/1989, 95% CI 4.0-5.9%), whilst women admitted to maternity had a 0.1% mortality rate (1/1725. 95% CI 0.0-0.4%) (Table 6 ). Mortality was more frequent in patients found to be hypoxemic during admission, with 21.7% of severely hypoxemic (SpO₂ < 90%) patients (110/506, 95% CI 18.4–25.6%), 3.8% (21/559, 95% CI 2.5–5.7%) of moderately hypoxemic patients, and 1.2% of patients not found to be hypoxemic (48/4113, 95% CI 0.9–1.6%).

Of the remaining patients in the cohort, 88.7% (5085/5731) were discharged, 4.5% (256/5731) were referred to another health facility, 0.6% (32/5731) absconded or left against medical advice, and 1.9% (108/5731) had were still admitted at the end of the study window.

A total of 1,180 healthcare workers were assessed for their comprehension of hypoxemia screening and management regarding the diagnosis and treatment (Table 7). The mean score was 7/12 (Fig. 2) with slight variations by cadre. Of respondents, 13.3% (157 out of 1180) scored above 80% (≥ 10 correct answers). Referral hospitals had the highest high-score rate at 19.5% whilst specialized hospitals had the lowest at 4.1%. Among HCW cadres, doctors had the highest performance, with 22.5% scoring above 80%, while nurses had 13.0% and midwives 8.9%.

The study highlights a high utilization of pulse oximetry (87.7%, 95% CI 86.8–88.5%) among inpatients on admission, with higher rates in neonates (96.4% 95% CI 94.6–97.6%) and pediatric patients (91.0%, 95% CI 88.0-91.8%) compared to adults (85.3% 95% CI 84.7–87.0%). Hypoxemia was found in 9.4% of the patients on admission (CI 8.6–10.2%), with a higher prevalence amongst neonates 27.9% (95% CI 24.4–31.6%). Among those experiencing hypoxemia, 92.2% of patients received oxygen therapy the same day (95% CI 88.9–94.6%), with the highest coverage seen in neonates (93.4%, 95% CI 90.8–95.4%). Patients found to be hypoxemic during admission with SpO₂ measurement less than 90% were more likely to die (21.7%, 95% CI 18.4–25.6%) compared to those with SpO₂ values above 93% (3.8%, 95% CI 2.5–5.7%). In measuring healthcare worker knowledge, it was found that knowledge gaps remain in screening of hypoxemia and management, with only 13.3% of staff achieving over 80% correctly (10 of 13 questions).

Pulse oximetry use on admission was found to be common practice across inpatient settings in Rwanda, with slightly more comprehensive practices in younger age groups, which reflects the higher vulnerability of neonates and children to hypoxemia, particularly in low-resource settings where conditions like pneumonia are prevalent. Patients admitted to the emergency and maternity wards had screening rates of 90.0% (CI 85.2–93.3%) and 90.9% (CI 56.0-98.8%), respectively. This indicates a shortfall in the use of pulse oximetry. The high volume of patients with acute conditions, coupled with understaffing, likely contributes to this issue. Consequently, screening for hypoxemia and less critical cases may be overlooked, which could undermine the quality of patient care. Although there is an improvement compared to previous studies of neonatal and pediatric patients in Rwanda in 2021(20), as well as findings from other sub-Saharan countries (17), there is still a gap to be addressed. It is imperative to ensure that all inpatients receive regular monitoring during their admission and that the dosage and duration of oxygen therapy are closely guided by their hypoxemia status.

Hypoxemia prevalence amongst inpatients closely aligns with findings in other settings (2, 17), with declining prevalence in increasing age groups from 27.9% of neonates (< 28 days), 12.3% of pediatrics (29 days – 14 years) and 5.7% of adults (15 or more years). In a global meta-analysis, a similar trend was found of 24.5% neonates (< 28 days), 12.1% of pediatrics (1 month – 17 years) and 10.8% of adults (18 or more) (21). This higher prevalence is expected given the association of hypoxemia with common childhood conditions such as pneumonia and sepsis.

In patients with hypoxemia, the majority were documented to receive oxygen therapy the same day 93.4% (95% CI 90.8–95.4%) with no significant gaps seen between age groups or wards. Whilst in a previous study in Rwanda found increases in oxygen coverage in subsequent days of admission, it was found that the majority of patients hypoxemic on admission received oxygen the same day with just 2.5% of these patients receiving it in the following days (20). This indicates an improvement in oxygen therapy provision or potential improvements in the documentation of oxygen prescriptions on the day of admission. The findings of this study demonstrate that the country performs well when compared to other lower-middle-income countries (LMICs). Reports show that access to pulse oximetry in various LMICs is 54.0% in smaller hospitals and 83% in tertiary facilities. Likewise, the availability of oxygen therapy is 58.0% in smaller hospitals and 86.0% in tertiary institutions (17).

Compared to other LMICs (22), Rwanda has made notable progress in the use of pulse oximetry and oxygen therapy in all inpatient age groups. This could be due to the implementation of comprehensive policies aimed at strengthening respiratory care, including clinical guidelines and job aids for children and adults (18, 19). The country’s national oxygen strategy, published after this study, highlights a multifaceted strategy that combines increased national oxygen production and key policy reforms with a strong focus on capacity building within the healthcare system (23). Capacity-building initiatives on hypoxemia screening and oxygen therapy have aimed to enhance the competencies of healthcare workers (23). This capacity-building initiative involved creating an e-learning platform where all clinicians were encouraged to participate and access resources at their convenience. In addition, on-the-job training for hypoxemia screening and management was decentralized, extending from the referral hospitals down to local health posts. Furthermore, to ensure the improvements are sustainable, comprehensive modules on hypoxemia screening and oxygen therapy were integrated into the curricula of clinical and allied pre-service education (24).

Whilst this study found considerable access to oxygen therapy; to maximize its benefits the therapy must be of high quality, which can be examined across different dimensions (25). Oxygen therapy should be timely, with minimum delay between a hypoxemic patient presenting and initiation of therapy. Treatment should be safe and effective, with appropriate duration and dose of treatment, therefore guided by regular monitoring with pulse oximetry and some patients require continuous monitoring. Some findings indicate there are potential gaps in the quality of therapy, such as the finding that 28.1% of patients who received oxygen had SpO₂ values of 94–100%. Whilst some patients might require oxygen for other reasons such as trauma, it does suggest further research is needed to ensure there is no over-prescription. Particularly amongst preterm neonatal patients, oxygen therapy is associated with increased risk of retinopathy of prematurity and permanent lung damage when given for long durations and to higher SpO₂ levels (26). There were gaps found in knowledge among healthcare professionals, suggesting whilst the core skills of managing hypoxemia are present, there is still necessity for increased focus on continuing education, mentorship, and training initiatives to ensure oxygen therapy is not only accessible but of high quality.

High mortality rates among severely hypoxemic patients (21.4%, 95% CI 17.6–25.8%) and in neonates (10.9%, 95% CI 8.6–13.6%) indicates there is still progress to be made in the quality of care. Oxygen therapy and respiratory care should be integrated with other aspects of care and delivered to a high standard, including adhering to clinical guidelines. As a medical emergency, hypoxemia should be detected rapidly and treated immediately. The national strategy prioritizes decentralizing diagnosis and treatment of hypoxemia to primary levels of care, which could show additional benefits in reducing severity of presenting cases through early detection, and more research is recommended to measure the impacts of this strategy (23).

Despite the valuable insights provided by the study findings, some limitations were noted. Reliance on patient records may introduce bias due to incomplete documentation, where pulse oximetry or oxygen therapy is undercounted. However, a simple random sampling of admission days aimed to enhance the study's variety and representativeness, and trained data collectors with a clinical background were used to minimize errors in collecting and interpreting clinical case notes. Documentation of SpO₂ and oxygen therapy (among other vital signs and treatments) is a basic standard of care, so even if pulse oximetry were being done but not recorded, this would be interpreted as inadequate care.

The supervised self-administered survey aimed to reduce bias by ensuring respondent anonymity and eliminating interviewer influence. However, the healthcare workers (HCWs) selected for training and eligible for the survey may differ in characteristics from the overall population of HCWs at the facility. Additionally, some response bias may have been introduced if there was differing ability to understand the survey questions; therefore, further research should aim to comprehensively understand healthcare worker knowledge in hypoxemia management to understand precise gaps that should be addressed with further training and guidance.

The study included 40 out of 55 hospitals in Rwanda, which is a large proportion of hospitals in the country and therefore highly representative. However, the facilities excluded hospitals which had previously received hypoxemia management strengthening activities from the government, it is likely therefore these hospitals excluded might have improved outcomes related to medical oxygen. Days were randomly selected across different study sites, improving the representativeness of the sample of patients included, although there might be seasonal variation outside of the study window that was not captured. The study was focused on inpatient clinical care and therefore did not address outpatient, policy environment, financial investments, or supply chain complexities, all crucial for lasting improvements in healthcare delivery.