Physiology Regarding Apnoeic Oxygenation During Nasal Cannula Therapy at Different Flow Rates
- Conditions
- Apnoeic Oxygenation
- Interventions
- Procedure: Jaw thrustProcedure: Videolaryngoscopy
- Registration Number
- NCT03478774
- Lead Sponsor
- Insel Gruppe AG, University Hospital Bern
- Brief Summary
This study compares under controlled conditions if different flow rates affect apnoea time after induction of anaesthesia and how CO2 clearance is influenced. Furthermore, this study enables to quantify the effects of increased pCO2 on vital parameters (e.g. blood pressure, cardiac output, cerebral perfusion, etc.) The investigators will enroll patients undergoing elective surgery at the University Hospital of Bern, Switzerland.
Once anesthesia has been induced, apnoea will set it. During this period, the investigators will compare different methods of apnoeic oxygenation for a maximum of 15 or 30 minutes.
Before discharge, an interview will be conducted, assessing complications and patient satisfaction.
- Detailed Description
Eligible, consenting adults will be prepared for general anaesthesia in the usual way consisting of ECG, pulse-oximetry, NarcotrendTM, a venous cannula and an arterial line for continuous blood pressure monitoring. They will receive additional monitoring such as transcutaneous measurement of pCO2 and O2, NIRS, and thoracic electrical impedance tomography (EIT, PulmoVista® 500, Draeger, Luebeck, Germany).
Normal pre-oxygenation (until etO2 is \> 90% or time \> 3 minutes) will occur. Anaesthesia will be started (= "induction") using Propofol and Fentanyl, using NarcotrendTM to measure depth of anaesthesia. All patients will receive a standard dose of neuromuscular blockage to facilitate airway management and total intravenous anaesthesia will be installed. Using the train of four measurement (TOF) full neuromuscular blockage with Rocuronium will be confirmed every 30 seconds. If necessary, additional dosage of neuromuscular blockage will be administered.
After administration of Rocuronium, possibility of mask ventilation will be confirmed and the sealed envelope with the randomization will then be opened. As a study intervention, the assigned method (HFNCT 70 l/min with either jaw thrust or laryngoscopy, or 10 l/min or 2l/min with the standard nasal canula, or 0.25l/min delivery of oxgen via a tracheal tube) will be installed and mask ventilation discontinued starting the apnoea period. Nasopharyngoscopy (EF-N slim, Acutronic, Hirzel, Switzerland) will confirm upper airway patency. Blood gas analysis will be conducted: baseline awake, start of apnoea, first minute after apnoea start, and every 2 minutes thereafter with a maximum of 75ml 150 ml in total. Other measurements (ECG, pulse-oximetry, blood pressure, NIRS, thoracic EIT, NarcotrendTM, PtcO2, PtcCO2) will be measured continuously over the study period The study intervention will end when one of the following criteria (study end-points) is met: SpO2 \<92%, PtcCO2 \> 100 mmHg or time \> 30 minutes.
When any of the end points is reached, patient-centred standard anaesthesia care will be continued, as planned for the case.
A post-operative interview will be conducted before discharge to evaluate injuries during airway management (bleeding, sore throat, hoarseness), pain, postoperative nausea and vomiting.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 125
- > 18 years
- Written informed consent
- Undergoing elective surgery
- Requiring general anesthesia
- Any Indication for fibre optic intubation
- Expected impossible mask ventilation
- Known coronary heart disease
- Known heart failure, NYHA classification ≥ 2
- Therapy including β-receptor antagonists
- Arrhythmias in need of anti-arrhythmic therapy (e.g. implanted cardio defibrillator)
- Peripheral occlusive arterial disease, Fontaine ≥ 2b
- Known stenosis of the (common or internal) carotid or vertebral arteries
- BMI > 35kg/m2 and BMI < 16kg/m2
- Hyperkalaemia (K > 5.5 mmol/l)
- Known COPD Gold classification ≥ 2
- Known pulmonary arterial hypertension, systolic > 35mmHg
- Known obstructive sleep apnoea syndrome in need of therapy
- High risk of aspiration (requiring rapid sequence induction intubation)
- Increased intracranial pressure
- Intracranial surgery
- Limited knowledge of German language
- Absent power of judgement
- Anaemia, Hb < 100 g/l
- Pregnancy (pregnancy test in all female patients)
- Neuromuscular disorder
- Known or suspected cervical spine instability
- Nasal obstruction, impossibility of nasal ventilation (both sides patent)
- Allergies or contra-indications to one or more of the used anaesthesia agents
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- SINGLE_GROUP
- Arm && Interventions
Group Intervention Description medium flow Oxygen 10 l/min These patients will receive oxygen 10l/min after induction of general anesthesia. Throughout the entire measurement period of 15 or 30 minutes, jaw thrust will be performed. Control Oxygen 70l/min These patients will receive HFNCT with oxygen 70l/min after induction of general anesthesia. Throughout the entire measurement period of 15 or 30 minutes, continuous videolaryngoscopy will be performed. High flow Oxygen 70l/min These patients will receive HFNCT with oxygen 70l/min after induction of general anesthesia. Throughout the entire measurement period of 15 or 30 minutes, jaw thrust will be performed. High flow Jaw thrust These patients will receive HFNCT with oxygen 70l/min after induction of general anesthesia. Throughout the entire measurement period of 15 or 30 minutes, jaw thrust will be performed. low flow Jaw thrust These patients will receive oxygen 2l/min after induction of general anesthesia. Throughout the entire measurement period of 15 or 30 minutes, jaw thrust will be performed. Control Videolaryngoscopy These patients will receive HFNCT with oxygen 70l/min after induction of general anesthesia. Throughout the entire measurement period of 15 or 30 minutes, continuous videolaryngoscopy will be performed. medium flow Jaw thrust These patients will receive oxygen 10l/min after induction of general anesthesia. Throughout the entire measurement period of 15 or 30 minutes, jaw thrust will be performed. minimal flow oxygen 0.25l/min These patients will receive a standard tracheal tubes after induction of general anesthesia, with 100% Oxygen and Minimum-flow 0.25l/min. The measurement period is 15 or 30 minutes. low flow Oxygen 2l/min These patients will receive oxygen 2l/min after induction of general anesthesia. Throughout the entire measurement period of 15 or 30 minutes, jaw thrust will be performed.
- Primary Outcome Measures
Name Time Method pCO2 increase in kPa/min 15 or 30 minutes (maximum apnea time) pCO2 will be measured transcutaneously throughout the apnea period
- Secondary Outcome Measures
Name Time Method Lowest Saturation During apnea period (until end-point is met or max. 15 or 30 minutes) Lowest SpO2 in %
Change in PaO2 in kPa During apnea period (until end-point is met or max. 15 or 30 minutes) Blood gas analyses as well as transcutaneous measurement
Change in cardiac output in L/min During apnea period (until end-point is met or max. 15 or 30 minutes) Cardiac output will be measured using pulse pressure measurement
Change in cerebral perfusion in % During apnea period (until end-point is met or max. 15 or 30 minutes) Near infrared spectroscopy will be measured continuously
Changes in end-expiratory lung impedance During apnoea time (until end-point is met or max. 15 or 30 minutes) To quantify atelectasis during apnoeic oxygenation
Change in invasive blood pressure During apnoea time (until end-point is met or max. 15 or 30 minutes) Measurement of change due to hypercarbia
Standard monitoring During apnoea time (until end-point is met or max. 15 or 30 minutes) Pulse oximetry SpO2 in %
Depth of anaesthesia During apnoea time (until end-point is met or max. 15 or 30 minutes) Using Narcotrend-EEG
Bilateral brain oxygenation During apnoea time (until end-point is met or max. 15 or 30 minutes) Using NIRS
Arterial blood gas analyses At 0, 1, 3, 5, 7, 9, 11, 13 and 15 minutes of apnoea or 0,1,3,5,7,9,13,15,17,19,21,23,25,27,29 and 30 min of apnoea. Bicarbonate in mmol
Postoperative questionnaire Morning of first postoperative day Visual analogue scale (VAS) : pain, nausea, vomiting, feeling worried or anxious, feeling sad or depressed, injuries, discomfort, any complications
Trial Locations
- Locations (1)
University Hospital Inselspital
🇨🇭Bern, Switzerland