PreOxygenation In RSI Anesthesia
PreOxygenation In RSI Anesthesia
Pre-oxygenation with high-flow nasal cannula oxygen has been evaluated in a limited number of
 studies and seems to be better than traditional preoxygenation with a tight fitting mask.
 Oxygenation with high-flow nasal cannula in apnea demonstrates that this could be done safely
 for up to 25 mins with preserved saturation. Based on this, the investigators want to
 evaluate whether this novel concept of preoxygenation can prolong the time to desaturation in
 emergency anesthesia while securing a possibly difficult airway. This may reduce the number
 of hypoxic events during intubation. This novel concept has already been tested in clinical
 practice in certain cases but not during rapid sequence induction for acute surgery.

 Objectives and Purpose The general purpose of this project is to compare a new preoxygenation
 technique based on humidified oxygen in a high-flow nasal cannula with traditional
 preoxygenation with a tight fitting mask during rapid sequence induction intubation with
 focus on gas exchange.
Pre-oxygenation with high-flow nasal cannula with 100% oxygen has been evaluated in a limited
 number of studies and seems to be equal or better than traditional preoxygenation with tight
 fitting mask. Apneic oxygenation with high-flow nasal cannula in apnea demonstrates that this
 could safely be don up to 25 minutes. Based on this, we can to evaluate whether this novel
 concept of preoxygenation can prolong the time before desaturation in emergency anesthesia
 and a difficult airway situation. This could ultimately reduce the number of damage to the
 airway and hypoxic injuries. This novel concept is already tested in clinical practice in
 certain cases and we strongly believe that a scientific evaluation of this approach is needed
 before a broad implementation.

 The patients will undergo regular pre-anesthetic evaluation and will be then be asked to
 participate in the study. Oral and written information will be given. A consent form will be
 signed.

 The patients will be randomized to either traditional preoxygenation or preoxygenation with
 high-flow nasal cannula (HFNC) oxygen.

 On arrival in the operating room standard patient monitoring will be applied (ECG, pulse
 oximetry, non-invasive blood pressure) and preparation for anesthesia induction will be done
 with the patients placed with a slightly elevated head, approximately 25º. Peripheral oxygen
 saturation (SpO2) will be noted when breathing room air. If an arterial line is planned this
 will be put in place before pre-oxygenation and a blood sample will be drawn when breathing
 room air Preoxygenation will hereafter take place either the traditional way or with a HFNC.
 The traditional preoxygenation consists of breathing 100% oxygen via a tight-fitting
 non-rebreathing facial mask with a fresh gas flow of ≥10 L/min of for ≥ 3 minutes. HFNC
 pre-oxygenation consists of application of nasal cannulae (Optiflow TM, Fisher & Paykel
 Healthcare, Auckland, New Zealand) in the nostrils and the patients will receive 40L/min of
 heated and humidified 100% oxygen for ≥ 3 minutes.

 After induction of anesthesia with RSI the airways will be kept open by manual adjustment by
 the anesthesiologist until intubation regardless of pre-oxygenation technique. During the
 laryngoscopy and intubation 70L/min of humidified 100% oxygen will be administered
 continuously by the nasal cannula left in place if HFNC oxygen is used.

 Endtidal carbon dioxide (ETCO2) will be noted before the start of pre-oxygenation and on the
 first breath after intubation. If an arterial line is in place blood gas samples will be
 taken before the start of pre-oxygenation (breathing room air) and when the endotracheal tube
 is in place.

 Output data:

 -  SpO2 breathing room air, at end of pre-oxygenation and one minute after intubation

 -  ETCO2 before pre-oxygenation and at first breath after intubation

 -  Time to intubation (measured from start of laryngoscopy to when ET tube correctly in
 place)

 -  Total time of high flow nasal cannula oxygen /traditional pre-oxygenation delivered

 -  Blood pressure

 -  Heart rate

 -  ASA classification level

 -  Smoker/non-smoker

 -  BMI

 -  Preoperative presence of lung condition (eg. chronic obstructive pulmonary disease
 (COPD), asthma) yes/no

 -  Preoperative oxygen therapy

 -  Known/treated obstructive sleep apnea (OSA) yes/no

 -  Type of surgery: abdominal yes/no

 -  Duration of surgery, hours

 -  Mallampati grade, thyromental distance, mouth opening and neck movement.

 -  Cormack & Lehane grade

 -  Number of attempts to intubate

 -  Use of bougie during intubation yes/no

 -  Cricoid pressure used yes/no

 -  Clinical suspicion of aspiration on intubation

 -  Subjective experience of the pre oxygenation measured on a Visual Analogue Scale

 Disruption criteria The patient doesn´t tolerate pre-oxygenation the way it is planned
 according to randomization.

 Statistics This is a randomized controlled study evaluating a novel concept and comparing it
 to a traditional technique. Continuous data will be presented as mean ± SD or 95% CI and
 categorical data as median and range. We will analyze the data using Prism 6.0 (GraphPad) or
 SPSS 24 (IBM). We do not know the primary outcome parameters (lowest saturation within 1 min
 after intubation), but with an estimation based partly on a previous study (Wimasalena et al.
 Ann Emerg Med 2015) we assume that the lowest saturation in the control group will be 93% and
 95% in the treatment group with a SD of 3%. Using a type I error of 5% and type II error of
 20% (power 80%) a sample size of 70 patients in each group was calculated. To allow for
 missed data and drop-outs we plan to include 100+100 patients (total of 200 patients). After
 inclusion of 80 patients an interim analysis will be performed for the primary outcome. A
 non-paired t-test will be performed to analyse the primary outcome.
Inclusion Criteria:

 1. Adult, >18 years old

 2. Emergency intubation where RSI is indicated

 3. Capable of understanding the study information and signing the written consent.

 4. Need for non-invasive ventilation

 Exclusion Criteria:

 1. BMI >35

 2. Pregnancy