Clinical Trial: A Comparison of the Detection of Hypoventilation During Deep Sedation Utilizing Nasal End Title CO@ Versus Transcutaneous CO2 Measurement Techniques
Study Status: Completed
Recruit Status: Completed
Study Type: Interventional
Official Title: A Comparison of the Detection of Hypoventilation During Deep Sedation Utilizing Nasal End Title CO@ Versus Transcutaneous CO2 Measurement Techniques
Brief Summary:
The estimation of the partial pressure of carbon dioxide (PCO2) in the arterial blood is used to judge the adequacy of ventilation during spontaneous and controlled ventilation. Although the gold standard for monitoring PCO2 remains arterial blood gas sampling, this requires an invasive procedure and provides only an intermittent estimate of what is frequently a continuously changing value. The solution to this problem has been the development and validation of accurate noninvasive monitoring techniques which provide a continuous intraoperative estimate of PCO2.The most commonly used noninvasive technique to monitor PCO2 is measurement of the end tidal CO2 (PECO2) . However, sampling errors and patient -related issues such as ventilation-perfusion mismatch, patient positioning or decreases in pulmonary blood flow may influence the accuracy of PECO2 monitoring (1-3). Nasal capnography has been proved to be an accurate monitor during the post-operative period (4) but its ability to accurately detect hypoventilation associated with deep sedation has not been studied.
According to the American Society of Anesthesiologist standards for basic monitoring, continuous capnography is required for all patients undergoing general anesthesia but it is optional for MAC/sedation cases. The need for CO2 monitoring has been studied by other medical specialties that use procedural sedation, including gastroenterology (12) and emergency medicine (13, 14) and many specialties now recommend capnography as a standard monitor.
Patients receiving supplemental oxygen may experience significant persistent hypoventilation leading to progressive hypercarbia and acidosis which may go undetected for a significant time interval since the routinely monitored SpO2 may be maintained within normal range. A recent study has shown that despite the fact that e
Detailed Summary:
A group of _40 patients scheduled to undergo Hysteroscopy surgery with deep sedation will be studied. Standard monitors will be utilized. Additionally a transcutaneous CO2 electrode will be attached to the ear lobe and a BIS monitor will be applied to the forehead.
The anesthetic management will be left to the discretion of the anesthesia provider (Anesthesia resident or CRNA, under the supervision of a faculty attending anesthesiologist).All patients will receive supplemental oxygen at 3L/ minute via nasal cannula, to maintain oxygen saturation greater than 90%.
Both the end tidal CO2 (ETCO2) and transcutaneous CO2 (TcCO2) (Linde Medical Sensors, Basel , Switzerland ) will be calibrated before use, according to the manufacturer's instruction.. The anesthesia provider will be blinded to the TcCO2 monitor but will have access to the ETCO2 values. The ETCO2 and TcCO2 values will be recorded simultaneously by an independent observer.
One arterial blood samples will be collected from each subject for measurement of PaCO2 at a deep level of sedation defined by a modified Ramsey score greater or equal to 5 (1= anxious/agitated/restless; 2= cooperative/oriented/tranquil; 3= drowsy/responds to commands only; 4= brisk response to shaking/loud sound; 5= sluggish response to shaking/loud sound; 6= no response) The ETCO2 and .TcCO2 will be recorded throughout the time of obtaining the blood sample every 15 seconds and the mean value will be used for comparison. Hypoventilation will be defined as a PaCO2 level greater than 45mmHg.
Sedation score (OASS) will be recorded on admission to recovery area. Time to meet discharge criteria will be recorded.
The experimental procedures: ABG draw, E
Sponsor: Northwestern University
Current Primary Outcome: TcCo2 vs PACo2 Difference [ Time Frame: 1 hour ]
Original Primary Outcome: Evaluate the correlation between PaCO2 - ETCO2 versus PaCO2- TcCO2 in detecting hypoventilation for patients undergoing deep sedation [ Time Frame: 1 hour ]
Current Secondary Outcome:
Original Secondary Outcome: Subjects with SaO2 less than 90% on 3L oxygen by nasal cannula. Subjects requiring airway supporting measures; jaw support, oral / nasal airway. Subjects converted to general anesthesia due to inadequacy of deep sedation [ Time Frame: 1 hour ]
Information By: Northwestern University
Dates:
Date Received: August 5, 2009
Date Started: June 2009
Date Completion:
Last Updated: June 25, 2014
Last Verified: June 2014
