Evaluation of Pupillary Distension Reflexes, as a Tool for the Monitoring of Analgesia for Patients in Intensive Care.

Evaluation of Pupillary Distension Reflexes, as a Tool for the Monitoring of Analgesia for Patients in Intensive Care.

Sedation-analgesia is an important therapy for patients in resuscitation. It requires a surveillance, in order to avoid excessive or insufficient dosages of sedative or nonmorphinics, sources of side effects. Yet, means of surveillance are limited in resuscitation care : variations of blood pressure and heart rate are not very sensitive criterias. Clinical scales to measure the sedation and analgesia level were proposed for patients in resuscitation, including the Richmond (RASS) sedation scale and the behavioural pain scale (BPS). The study of pupillary dilatation's reflex (RDP) due to a nociceptive stimulation is a tool proposed for the monitoring of the analgesia peroperative for patients under general anaesthetic. Yet, there isn't any study that measured the analgesia threshold by pupillometry for patients in resuscitation receiving a sedation-analgesia.

The main goal of this study is to measure the minimum intensity of a painful stimulation (tetanus), leading to a 10% raise of RDP in a cohort of patients in resuscitation care receiving sedation-analgesia continuously.

Secondary goals will be to bring this measures back to the pain score BPS and the pupillary diameter measured during a painful care (tracheal aspiration), as well as morphinics dosage.

Inclusion Criteria:

• Intubated and Mechanically Ventilated Patients receiving by continuous intravenous an hypnotic sedation (midazolam or propofol) associate with a morphine type drug (fentanyl, sufentanil, rémifentanil, or morphine) since at least 6 hours and for a predictable duration over 24 hours.
• Both gender
• Adult over 18 years

Exclusion Criteria:

• Neuromuscular pathology that does not allow the use of clinical scales in order to measure sedation-analgesia : tetraplegia, resuscitation neuromyopathy, curares.
• Intracranial hypertension (intracranial pressure over 20 mmHg) whatever the cause (traumatique, vasculaire, tumorale).
• Dysautonomia altering the pupillary dilatation's reflex (RDP) : old diabetes with diabetic retinopathy, multiple sclerosis, systemic amylose.
• Treatment in progress which may affect the pupillary dilatation's reflex (RDP) : antiemetic (droperidol, métoclopramide), alpha-2 agoniste (clonidine).
• Ocular pathology
• Opiate addiction
• Refusal by a patient
• Pregnant women