EPO2-A: Evaluation of Pre-Oxygenation in Morbid Obesity: Effect of Position and Positive Pressure Ventilation

Obesity, Morbid Clinical Trial

— EPO2-A  

Official title:

EPO2-A: Evaluation of Different Pre-Oxygenation Condition in Morbid Obesity: Effect of Position and Positive Pressure Ventilation During General Anesthesia Induction

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02590406
• Other study ID #: IUCPQ 21211
• Status: Completed
• Phase: N/A
• Start date: September 2015
• Est. completion date: March 2016

Study information

• Verified date: March 2020
• Source: Laval University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The risk of complication associated with airway in obese patient is important. The result of pre-oxygenation gives the clinician a prolonged non-hypoxic apnea time. The relation between FRC and non-hypoxic apnea time has been correlated. However, the best condition to accomplish the pre-oxygenation in morbidly obese patient has yet to be described in the medical literature. A study previously done in our hospital (EPO2-PV) compared the effect of different positions and ventilation modes on the FRC in the laboratory. A significant difference has been established on the FRC between the inverse Trendelenburg position with positive pressure ventilation and the head up ("beach-chair") position without positive pressure. The current study, EPO2-A is designed to compared the two positions and ventilation modes during the induction of general anesthesia on morbidly obese and correlate the difference in FRC to difference in apnea time.

Description:

Obesity prevalence in the population is increasing. Thus a growing number of obese patient need surgical interventions. These patients have a four time higher risk of suffering of serious complication in relation with their airway management compare with non-obese patients. This is explained by an increased incidence of difficulty with the ventilation and intubation of the obese. The time available for the clinician to manage the airway is define by the non hypoxic apnea time. This laps of time is dependent of the oxygen stocks of the patient, which are dependent of the functional residual capacity (FRC) and his oxygen consumption. For a non-obese patient, a normal pre-oxygenation of three minutes at 100% of oxygen allows a non hypoxic apnea time (oxygen saturation > 90%) of 8,9 minutes. However, for the morbidly obese, this time is cut to less than three minutes.

The major goal of the pre-oxygenation is to increase the alveolar partial pressure of oxygen available in the end-expiratory pulmonary volume. This can be done by replacing the nitrogen in the alveolus by oxygen and by increasing the pulmonary stocks, the FRC. It has been demonstrated that the FRC after the induction of anesthesia is cut by half for the obese. This reduction is explained by a diminished thoracic compliance and an increase of the dependent lung regions' atelectasis because of a more cephalic position of the diaphragm.

Various pre-oxygenation methods have been described to prolong the non hypoxic apnea time in the obese population. Some proposed pre-oxygenation strategies with the patient in the head up position (beach chair). It is a position derived from the ramped position described as the best to visualized the obese patients' glottis. Others proposed pre-oxygenation strategies with positive pressure ventilation, but only the supine position has been studied concomitantly.

Individually, these techniques of pre-oxygenation are superior to the combination of supine position and no positive pressure. Indeed, studies demonstrated that the beach chair position (derived from the ramped position) or the positive pressure pre-oxygenation in supine position diminished the time needed to obtain a satisfactory pre-oxygenation (End-expiratory oxygen fraction >0,9) and a longer non hypoxic apnea time. Sill, these strategies have never been combined in the same protocol.

The beach chair position without positive pressure ventilation has become the standard of care because it is the position that allows the best glottis view. Though, it has been shown by Boyce and coll. that the reverse Trendelenburg position, and not the beach chair, increased the non hypoxic apnea time, the recuperation time and the minimal saturation obtained compared to the supine position. We think that there is an advantage to use the reverse Trendelenburg position to optimize the non hypoxic apnea time. Indeed, our hypothesis is that there will be less pressure on the diaphragm in comparison with the beach char position.

A studied realized by our group (EPO2-PV) evaluated the effect of three positions (Reverse Trendelenburg, beach chair and supine) and two ventilation strategies (spontaneous ventilation with or without positive pressure) on morbidly obese FRC in laboratory. The results showed a statistically significant difference on the FRC after a pre-oxygenation with positive pressure compared with the pre-oxygenation without positive pressure, and this regardless of the position. Moreover, for both ventilation strategies, results demonstrated a statistically significant superiority between the FRC obtained after pre-oxygenation in reverse Trendelenburg compared with the beach chair and the supine position. No improvement has been shown with the beach chair position.

Thereby, the current study will try to correlate the FRC results obtained in laboratory in actual non hypoxic apnea time in the operating room. This research design tries to compare, in patient receiving general anesthesia for bariatric surgeries, the effect of the pre-oxygenation with positive pressure and the reverse Trendelenburg position, on the non hypoxic apnea time in comparison with the actual standard of care, beach chair position without positive pressure ventilation.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 50
• Est. completion date: March 2016
• Est. primary completion date: January 2016
• Accepts healthy volunteers: No
• Gender: All
• Age group: 21 Years to 70 Years

Eligibility

Inclusion Criteria:

• BMI > 40

• Abdominal obesity : waist circumference: > 115 for the women waist circumference > 130 for the men

Exclusion Criteria:

• Facial hair

• Cranio-facial abnormality

• Asthma (continuous treatment)

• COPD (FEV1 < 80%)

• Severe cardiovascular disease (NYHA > 3)

• Pregnancy

• Tobacco use

• Know or suspected difficulty with intubation

• Severe GERD or risk of aspiration

Related Conditions & MeSH terms

• Obesity
• Obesity, Morbid

Intervention

Procedure:
• Beach chair (BC) and ZEEP
Table Position: Beach chair, Inclination of the upper part of the table at 25 degrees, breaking at the patient's hips ZEEP: 3 minutes pre-oxygenation with tidal volumes, FiO2 100%, mouth piece used as a ventilatory interface
• Reverse Trendelenburg and NIPPV
Table Position: Reverse Trendelenburg, Inclination of the whole table at 25 degrees from an horizontal plane, head up. NIPPV: 3 minutes of pre-oxygenation with 8 cm H2O positive pressure and 10 cm H2O PEEP. Trigger set at 1,5 L/min, mouth piece is used as a ventilatory interface

Locations

Country	Name	City	State
Canada	Institut universitaire de cardiologie et de pneumologie de Québec	Québec city	Quebec

Sponsors (1)

Lead Sponsor	Collaborator
Laval University

Country where clinical trial is conducted

Canada, 

References & Publications (20)

Altermatt FR, Muñoz HR, Delfino AE, Cortínez LI. Pre-oxygenation in the obese patient: effects of position on tolerance to apnoea. Br J Anaesth. 2005 Nov;95(5):706-9. Epub 2005 Sep 2. — View Citation

Baraka AS, Hanna MT, Jabbour SI, Nawfal MF, Sibai AA, Yazbeck VG, Khoury NI, Karam KS. Preoxygenation of pregnant and nonpregnant women in the head-up versus supine position. Anesth Analg. 1992 Nov;75(5):757-9. — View Citation

Boyce JR, Ness T, Castroman P, Gleysteen JJ. A preliminary study of the optimal anesthesia positioning for the morbidly obese patient. Obes Surg. 2003 Feb;13(1):4-9. — View Citation

Collins JS, Lemmens HJ, Brodsky JB, Brock-Utne JG, Levitan RM. Laryngoscopy and morbid obesity: a comparison of the "sniff" and "ramped" positions. Obes Surg. 2004 Oct;14(9):1171-5. — View Citation

Cook TM, Woodall N, Frerk C; Fourth National Audit Project. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: anaesthesia. Br J Anaesth. 2011 May;106(5):617-31. doi: 10.1093/bja/aer058. Epub 2011 Mar 29. — View Citation

Coussa M, Proietti S, Schnyder P, Frascarolo P, Suter M, Spahn DR, Magnusson L. Prevention of atelectasis formation during the induction of general anesthesia in morbidly obese patients. Anesth Analg. 2004 May;98(5):1491-5, table of contents. — View Citation

Cressey DM, Berthoud MC, Reilly CS. Effectiveness of continuous positive airway pressure to enhance pre-oxygenation in morbidly obese women. Anaesthesia. 2001 Jul;56(7):680-4. — View Citation

Damia G, Mascheroni D, Croci M, Tarenzi L. Perioperative changes in functional residual capacity in morbidly obese patients. Br J Anaesth. 1988 Apr;60(5):574-8. — View Citation

Delay JM, Sebbane M, Jung B, Nocca D, Verzilli D, Pouzeratte Y, Kamel ME, Fabre JM, Eledjam JJ, Jaber S. The effectiveness of noninvasive positive pressure ventilation to enhance preoxygenation in morbidly obese patients: a randomized controlled study. Anesth Analg. 2008 Nov;107(5):1707-13. doi: 10.1213/ane.0b013e318183909b. — View Citation

Dixon BJ, Dixon JB, Carden JR, Burn AJ, Schachter LM, Playfair JM, Laurie CP, O'Brien PE. Preoxygenation is more effective in the 25 degrees head-up position than in the supine position in severely obese patients: a randomized controlled study. Anesthesio — View Citation

Gambee AM, Hertzka RE, Fisher DM. Preoxygenation techniques: comparison of three minutes and four breaths. Anesth Analg. 1987 May;66(5):468-70. — View Citation

Gander S, Frascarolo P, Suter M, Spahn DR, Magnusson L. Positive end-expiratory pressure during induction of general anesthesia increases duration of nonhypoxic apnea in morbidly obese patients. Anesth Analg. 2005 Feb;100(2):580-4. — View Citation

Jense HG, Dubin SA, Silverstein PI, O'Leary-Escolas U. Effect of obesity on safe duration of apnea in anesthetized humans. Anesth Analg. 1991 Jan;72(1):89-93. — View Citation

Juvin P, Lavaut E, Dupont H, Lefevre P, Demetriou M, Dumoulin JL, Desmonts JM. Difficult tracheal intubation is more common in obese than in lean patients. Anesth Analg. 2003 Aug;97(2):595-600, table of contents. — View Citation

Lane S, Saunders D, Schofield A, Padmanabhan R, Hildreth A, Laws D. A prospective, randomised controlled trial comparing the efficacy of pre-oxygenation in the 20 degrees head-up vs supine position. Anaesthesia. 2005 Nov;60(11):1064-7. — View Citation

Langeron O, Masso E, Huraux C, Guggiari M, Bianchi A, Coriat P, Riou B. Prediction of difficult mask ventilation. Anesthesiology. 2000 May;92(5):1229-36. — View Citation

Lellouche F, Dionne S, Simard S, Bussières J, Dagenais F. High tidal volumes in mechanically ventilated patients increase organ dysfunction after cardiac surgery. Anesthesiology. 2012 May;116(5):1072-82. doi: 10.1097/ALN.0b013e3182522df5. — View Citation

Levitan RM, Mechem CC, Ochroch EA, Shofer FS, Hollander JE. Head-elevated laryngoscopy position: improving laryngeal exposure during laryngoscopy by increasing head elevation. Ann Emerg Med. 2003 Mar;41(3):322-30. — View Citation

Pelosi P, Croci M, Ravagnan I, Tredici S, Pedoto A, Lissoni A, Gattinoni L. The effects of body mass on lung volumes, respiratory mechanics, and gas exchange during general anesthesia. Anesth Analg. 1998 Sep;87(3):654-60. — View Citation

Tanoubi I, Drolet P, Donati F. Optimizing preoxygenation in adults. Can J Anaesth. 2009 Jun;56(6):449-66. doi: 10.1007/s12630-009-9084-z. Epub 2009 Apr 28. Review. — View Citation

* Note: There are 20 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Non Hypoxic Apnea Time	Change of Non-hypoxic apnea time in obese patient during a General Anesthesia induction, as a result of different pre-oxygenation position and ventilation mode; 1-Beach Chair and No positive pressure ventilation, 2-Reverse Trendelenburg and positive pressure ventilation and PEEP. End of measure time frame is 5 minutes after intubation	After a 3 minutes pre-oxygenation period
Secondary	Time to Expired Oxygen Fraction > 0,9	Evaluation of time needed to obtain an expired fraction of oxygen of > 0,9 in the two groups during the pre-oxygenation	During the pre-oxygenation period
Secondary	Maximum Expired Fraction of Oxygen Obtained	Evaluation of the maximum expired oxygen fraction obtained in the two groups	After 3 minutes of pre-oxygenation
Secondary	Minimum Arterial Saturation of Oxygen Obtained	Evaluation of the minimal saturation obtained after the resumption of the ventilation	After the end of the Non-hypoxic apnea time
Secondary	Time to 97% Saturation		Evaluation of the time needed to the beginning of the ventilation to the moment where the saturation is 97%
Secondary	Hemodynamic Changes	Evaluation of the changes in vital signs during and after the pre-oxygenation phase in the two combinations of position and ventilation mode	From the beginning of the pre-oxygenation to the end of the protocol