The Effect of Oxygen Flow Rate on End-tidal CO2 During Deep Sedation

The Effect of Different Oxygen Flow Rates on End-tidal Carbon Dioxide Monitoring During Procedural Sedation in Patients Undergoing Minor Gynaecological Procedures.

This study aims to detect the effect of different O2 flow rates on end tidal carbon dioxide level in patients scheduled for minor gynaecological procedures under deep sedation using laryngeal mask airway.

• Primary outcome was measuring end tidal carbon dioxide ( EtCO2 ) non invasively by laryngeal mask all through the procedure.
• Secondary outcomes included peripheral O2 saturation, hemodynamics, time to recovery, total propofol dose, patients' satisfaction, sedation score, and complications.

Procedural sedation (PS) is generally considered to include the stages of moderate and deep sedation of the continuum of anaesthesia . The clinical goals of procedural sedation are to alleviate apprehension, ameliorate the examination, findings, minimize the patients' memories of the incident and to control pain and distress during diagnostic and interventional medical procedures a lot of minor gynaecological procedures can be performed under moderate to deep sedation as ( D&C Biopsy, hysteroscopic polypectomy and diagnostic hysteroscopies ) The greatest threat to the safety of sedated patient is airway compromise and or respiratory depression . To decrease the risk of airway and respiratory complications, careful attention must be directed toward the appropriate selection of medications, adherence to dosing recommendations, and most importantly the identification of the high-risk patient.

Regardless of the clinical scenario or the medications used, appropriate monitoring of the patient's respiratory and physiologic functions is mandatory to rapidly identify respiratory compromise.

Respiratory function is usually evaluated by observation of qualitative clinical signs (respiratory rate, depth and effort) and oxygen saturation monitoring. Oxygen desaturation in pulse oximetry usually occurs as a delayed sign , so if the capnograph monitor is used, any increase in EtCO2 during hypoventilation can alert the observing anesthetist to avoid hypoxemia. Capnography is a respiratory monitoring device that has become an accepted standard of care for PS in many circumstances. So, the American Society of Anesthesiology standards for Basic Anesthetic Monitoring require the use of capnography for both moderate and deep sedation.

Inclusion Criteria:

1. Patient aged 18-45 years
2. ASA physical status l : ll
3. Minor elective gynaecological procedures lasting less than 30 minutes ( D&C biopsy, hysteroscopic polypectomy and diagnostic hysteroscopy )

Exclusion Criteria:

• We will exclude from the study patients with the following:

  1. Patient refusal to participate in this study.
  2. ASA lll or more.
  3. Lengthy procedures taking more than 30 minutes
  4. Contraindication for the use of laryngeal mask airway as ( pharyngeal pathology, risk of aspiration and airway obstruction below larynx)
  5. BMI more than 35