New ingestible sensor for non-intrusive sleep disorder monitoring developed by MIT and collaborators

A recent Device study reported the effectiveness of an ingestible vitals-monitoring pill (VM pill) to monitor vital signs, including heart and respiratory rate based on a human trial.

History and importance of ingestible electronics

According to the Centers for Disease Control and Prevention (CDC), a record increase in deaths due to drug or opioid overdose has been estimated in 2022. This number is steadily increasing despite the precautionary measures implemented by the President’s Commission on Combating Drug Addiction and the Opioid Crisis in 2017.

Opioid overdose causes opioid-induced respiratory depression (OIRD), which could be fatal or generate hypoxia-related complications, such as cardiac arrest, organ system damage, or psychosis.

Considering this overwhelming number of drug deaths, the President’s Commission and the Stanford-Lancet Commission strategized to develop an autonomous delivery system for opioid antagonists for the detection of OIRD in patients. Typically, opioid antagonists are used to alleviate OIRD. It must be noted that many times healthcare providers and caregivers do not know whether a patient is experiencing OIRD outside a healthcare facility. Hence, early detection is imperative for an optimal opiate antagonist intervention.

Obstructive sleep apnea (OSA) involves partial or complete obstruction of upper respiratory airways. Diagnosis of this respiratory disease involves the use of sensors to detect changes in airflow and oxygen hemoglobin. Although advancements in algorithms in portable devices and wearables help in the early detection of respiratory changes, many of these devices do not meet clinical standards.

A wireless, ingestible device can measure respiration rate and other vital signs from within the human gastrointestinal tract. The concept of ingestible electronics was first introduced in the 1950s to measure temperature, pH, and pressure.

However, the first video capsule endoscope system was introduced only after the 1990s. It must be noted that this area of research remains extremely active, and scientists have designed many devices. Vital signs measurements play an important role in the decision-making of clinicians across varied conditions.

Development and effectiveness of VM pill

The current study described the formulation of a VM pill that can determine human heart rate (HR) and respiratory rate (RR). This device can be used to evaluate polysomnography (PSG), i.e., sleep study and opioid-induced respiratory depression (OIRD). A VM pill consists of a microcontroller, accelerometer, memory, and radio.

The VM pill is an ingestible, wireless, vitamin-capsule-sized device that uses a conventional configuration of off-the-shelf electronic sensors and integrated circuits for ballistic measurements. When the device reaches the gastrointestinal tract, the movement of the abdomen during breathing is evaluated using an accelerometer. The accelerometer data and time stamps are stored in the device memory, which is periodically transferred to an external receiver for analysis.

During the development of the VM pill, it was hypothesized that an ingestible electronic device could capture the multi-modal signal that enables accurate diagnosis and monitoring of a range of health conditions including the respiratory and cardiovascular systems.

The current study evaluated the efficacy of VM pills based on opiate overdose and sleep study. This is a human-based measurement of vital signs from within the gastrointestinal tract using the newly developed ingestible device. The accuracy of RR and HR measurements was assessed and compared to existing clinical data generated from vital sign-monitoring devices. 

This human trial was conducted between December 2021 and August 2022, and 2,293 participants were recruited for this study. Based on the eligibility criteria, ten participants were selected for the first human trial to evaluate the VM pill. The mean age of the participants was 41 years. No adverse effects during the swallowing of VM pill or bowel obstruction were observed.

It was essential to make the device smaller as it enabled the device to remain in the stomach for the entire operating period, i.e., approximately one week. It provided weekly data on the vital signs of participants. This study hypothesized that sleep apnea patients could be used to develop models for OIRD evaluations because the former condition is physiologically similar to respiratory depression associated with opioid overdose.

The current first-in-human research study indicated the possibility of validating and commercially using VM pills to measure RR and cardiac signals from within gastrointestinal tracts. The performance of this device was also evaluated in a sleep laboratory, which revealed its capacity to sense HR and RR in the presence of continuous positive airway pressure (CPAP). Furthermore, experimental outcomes indicated the capacity of VM pill to detect apneic events.

Conclusions

Based on the experimental results, the commercial version of VM pills could positively improve human factors. This device can be used to detect patients with OIRD. In the future, gastric residency technology could be incorporated into the VM pill for multiple functions. In this context, this device can be retained within the stomach for a week, and the closed-loop system could detect apneic episodes.

The insertion of the aforementioned technology could offer on-demand drug release upon automatic detection of OIRD and reverse opioid overdose. This system will positively help reduce adverse effects and prevent drug deaths.

Written by

Dr. Priyom Bose

Priyom holds a Ph.D. in Plant Biology and Biotechnology from the University of Madras, India. She is an active researcher and an experienced science writer. Priyom has also co-authored several original research articles that have been published in reputed peer-reviewed journals. She is also an avid reader and an amateur photographer.