Development and testing of Artificial Intelligence based mobile application to achieve cataract backlog-free status in Uttar Pradesh, India.

BACKGROUND: Uttar Pradesh (UP), the most populous state in India, has about 36 million people aged 50 years or older, spread across more than 100,000 villages. Among them, an estimated 3.5 million suffer from visual impairments, including blindness due to untreated cataracts. To achieve cataract backlog-free status, UP is required to screen this population at the community level and provide treatment to those suffering from cataracts. We envisioned an AI-powered primary screening app utilizing eye images, deployable to frontline health workers for community-level screening. This paper outlines insights gained from developing the AI mobile app "Roshni" for cataract screening. METHOD: The AI-based cataract classification model was developed using 13,633 eye images and finalized after three stages of experiments, detecting cataracts in images focused on the eye, iris, and pupil. Overall, 155 experiments were conducted using multiple deep learning algorithms, including ResNet50, ResNet101, YOLOv5, EfficientNetV2, and InceptionV3. We established a minimum threshold of 90 % specificity and sensitivity to ensure the algorithm's suitability for field use. RESULTS: The cataract detection model for eye-focused images achieved 51.9 % sensitivity and 87.6 % specificity, while the model for iris-focused images, using a good/bad iris filter, achieved 52.4 % sensitivity and 93.3 % specificity. The classification model for segmented-pupil images, employing a good/bad pupil filter with UNet-based semantic segmentation model and EfficientNetV2, yielded 96 % sensitivity and 97 % specificity. Field testing with 302 beneficiaries (604 images) showed an overall sensitivity of 86.6 %, specificity of 93.3 %, positive predictive value of 58.4 %, and negative predictive value of 98.5 %. CONCLUSION: This paper details the development of an AI mobile app designed to facilitate community screening for cataracts by frontline health workers.

Ambulatory short-term mechanical circulatory support: facilitates recovery and prepares patients for definitive therapy.

Short-term mechanical circulatory support (ST-MCS) devices have been traditionally deployed in patients with cardiogenic shock, advanced heart failure, cardiovascular collapse, and cardiorespiratory failure. Limitations of the mechanical support devices are typically related to mobility of the patient since the access is frequently through femoral vasculature. This limits the time the patient can be supported by mechanical circulatory support (MCS). We describe deployment of ST-MCS using alternate access such as the subclavian/axillary artery that facilitates ambulation of the patient. These include the deployment of intra-aortic balloon pump (IABP) through the subclavian artery, Impella pump through the axillary/subclavian artery, and extracorporeal membrane oxygenation (ECMO) using the subclavian artery and jugular vein.

ECMO as a bridge to cardiac surgery: stabilizing unstable patients for a definitive procedure.

Introduction: Extracorporeal membrane oxygenation (ECMO) in adults has been used in post-cardiotomy patients who decline hemodynamically. Cardiogenic shock in patients with potential surgically correctable cardiac conditions are at significantly higher risk for post-operative morbidity and mortality. We present experience with a pre-emptive approach of ECMO institution pre-operatively to stabilize patients with cardiogenic shock. Materials and methods: This study expands on a pilot study with a group of twenty patients who were supported with ECMO pre-operatively in different institutions over a period between 2011 and 2021. The patients presented with cardiogenic shock. Peripheral veno-arterial (VA) ECMO support was used in all the patients. Cardiac surgery was performed via median sternotomy utilizing the in situ ECMO cannulae to institute cardiopulmonary bypass (CPB). Results: Seventeen patients were weaned off ECMO support following a mean duration of support of 156 h. Fifteen patients survived to discharge. The 30-day mortality and in-hospital mortality were 25% (expected 67% by European System for Cardiac Operative Risk Evaluation (EuroSCORE) II). The causes of mortality included persistent bleeding in 2 patients due to liver dysfunction, and one with low platelet counts. The other two had multi-organ failure. Conclusions: Variable period of pre-operative ECMO support provides hemodynamic stability and may prevent or reverse the multi-organ dysfunction if instituted on time in patients presenting with cardiogenic shock. This strategy allows cardiac surgery to be performed with acceptable risk.

Predictors of atrial fibrillation post coronary artery bypass graft surgery: new scoring system.

BACKGROUND: Atrial fibrillation (AF) following coronary artery bypass graft surgery (CABG) is common and results in significant increases in hospital stay and financial encumbrance. OBJECTIVE: Determine and use the predictors of postoperative AF (POAF) following CABG to develop a new predictive screening tool. METHOD: A retrospective case-control study evaluated 388 patients (98 developed POAF and 290 remained in sinus rhythm) who undertook CABG surgery at Townsville University Hospital between 2016 and 2017. The demographic profile, risk factors for AF including hypertension, age≥75 years, transient ischaemic attack or stroke, chronic obstructive pulmonary disease (HATCH) score, electrocardiography features and perioperative factors were determined. RESULTS: Patients who developed POAF were significantly older. On univariate analysis HATCH score, aortic regurgitation, increased p-wave duration and amplitude in lead II and terminal p-wave amplitude in lead V1 were associated with POAF; as were increased cardiopulmonary bypass time (103.5±33.9 vs 90.6±26.4 min, p=0.001) and increased cross clamp time. On multivariate analysis age (p=0.038), p-wave duration ≥100 ms (p=0.005), HATCH score (p=0.049) and CBP Time ≥100 min (p=0.001) were associated with POAF. Receiver operating characteristic curve demonstrated that with a cut-off of ≥2 for HATCH score, POAF could be predicted with a sensitivity of 72.8% and a specificity of 34.7%. Adding p-wave duration in lead II >100 ms and cardiopulmonary bypass time >100 min to the HATCH score increased the sensitivity to 83.7% with a specificity of 33.1%. This was termed the HATCH-PC score. CONCLUSION: Patients with HATCH scores ≥2, and those with p-wave duration >100 ms, or cardiopulmonary bypass time >100 min were at greater risk of developing POAF following CABG.