Fighting against the pain caused by the disease or by the diagnostic and therapeutic procedures for children is a daily and essential concern of health care in the pediatric sector. The quantification of pain is needed to effectively adjust analgesic therapy while limiting the side effects of treatment. Nowadays many scales are validated for children, but they are based on one-off measures and hetero assessments are often subjective and dependent on many factors including the presence of staff to children's sides.

Recent developments in the analysis of the cardiac signal in real time under the influence of autonomic control, have led to the development of a new painful stress quantification index. A monitor has recently been developed and provides an index of nociception and analgesia (ANI index). The validation of this nociception index has not been validated for pediatric care in a sector where particular attention is given to control pain.

The main purpose of this study is to show the consistency of the index compared to a validated pain scale and used routinely in non-sedated children hospitalized in pediatric intensive care units. The caregiver will have the opportunity to fine tune the effective treatment.

Fighting against the pain caused by the disease or by the diagnostic and therapeutic procedures for children is a daily and essential concern of health care in the pediatric sector. The quantification of pain is needed to effectively adjust analgesic therapy while limiting the side effects of treatment. Nowadays many scales are validated for children, but they are based on one-off measures and hetero assessments are often subjective and dependent on many factors including the presence of staff to children's sides.

Recent developments in the analysis of the cardiac signal in real time under the influence of autonomic control, have led to the development of a new painful stress quantification index. A monitor has recently been developed and provides an index of nociception and analgesia (ANI index). It is based on the study of the variability of the heart rate control changes in sympathetic and parasympathetic systems in response to stimuli. Clinical correlations have been completed for most of adult patients during or after general anesthesia. The validation of this nociception index has not been validated for pediatric care in a sector where particular attention is given to control pain.

The main purpose of this study is to show the consistency of the index compared to a validated pain scale and used routinely in non-sedated children hospitalized in pediatric intensive care units. This study is based on a real-time analysis of the perception of pain in children. It is a critical validation step that could dramatically change the treatment of pediatric patients in intensive care and pediatric intensive care units by facilitating real-time patient management. The caregiver will have the opportunity to fine tune the effective treatment. The validation of this stool will allow the pain measure for children highly sedated or presenting a neuromotor handicap.

Inclusion Criteria:

- Children hospitalized in pediatric intensive-care unit of the University Hospital of Saint-Etienne, painful and receiving analgesic treatment of level 2 or 3.

Exclusion Criteria:

• Children in therapy or neurological coma,
• Children enjoying a treatment known to change the ortho or parasympathetic system.

The study will involve 30 children aged between 2 to 18 years old who are not sedated, hospitalized in the pediatric intensive-care unit of the University Hospital of Saint-Etienne. They are expected to express an acute sensation of pain. This pain can be the result of a surgical procedure, a diagnostic or therapeutic procedure or a condition known as painful. All children studied benefit from analgesic treatment levels 2 or higher.