Subjects will use the Gabi system on a daily basis for 3 months, each time the subject is resting or asleep. The Gabi system will recording the SpO2, pulse rate, respiratory rate and movements of the subject.

The objective of this study is to perform a first assessment of the range of most potentially clinically relevant indications for use of the Gabi system for children < 6 years old with underlying medical conditions.

This is performed by asking HCPs to review the data measured by the Gabi system after taking a medical decision independently from the Gabi data and to assess the potential clinical utility of the Gabi system.

The usability of the system will also be assessed throughout questionnaires filled out by the HCPs and by the caregivers.

*During this study, the data collected by the Gabi system are not intended to be used by caregivers or HCPs to take any (medical) decisions.

Inclusion Criteria:

1. Infants and children < 6 years old.

2. Subjects who present at least one of the following underlying medical conditions:

   1. Subjects who underwent a congenital cardiac or cardiopulmonary surgery recently and could benefit from an additional post-surgery monitoring at home, per the investigator's opinion.
   2. Subjects at risk awaiting surgery.
   3. Subjects hospitalized following a severe respiratory condition within the past 2 weeks requiring invasive or non-invasive ventilation or oxygen therapy.
   4. Subjects hospitalized following a severe cardiovascular condition within the past 2 weeks, including severe heart failure, tachycardia or bradycardia.
   5. Subjects with chronic respiratory disease, such as asthma, developmental or cardiovascular conditions who could benefit from medical monitoring at home, per the investigator's opinion.
   6. Subjects with chronic respiratory support at home.
   7. Premature babies who required intensive neonatal care.
   8. Subjects hospitalized following a Brief Resolved Unexpected Event (BRUE) within the past 2 weeks.
   9. A clinical risk identified by the investigator which justifies the potential benefit of having a Gabi system used by the subject

3. Subject is (or is willing to be) followed up by an HCP of the investigation site during the duration of the study.

4. Signed informed consent form prior to performing any study specific procedure.

5. Willing and likely (based on the investigator's judgement) to comply with all study requirements.

Exclusion Criteria:

1. Weight < 2.5 kg.
2. Subject presenting an anatomical limitation that would prevent the use of the Gabi system.
3. Subjects presenting a motor disorder that would prevent the use of the Gabi system (with the exception of epilepsy ).
4. Subjects participating in another interventional clinical study (with the exception of registries), which may have an impact on this study outcomes, based on the investigator's judgement.