The Effect of High-flow Nasal Oxygenation vs. Low-flow Nasal Oxygenation on Oxygen Saturation During Analgo-sedation in Obese Adult Patients, Randomized Controlled Trial
试验速览
- 阶段
- 不适用
- 发起方
- 入组人数
- 126
- 主要终点
- Change of peripheral blood oxygenation (SpO2),
研究概览
简要总结
Obesity is omnipresent problem in everyday anesthesiology practice associated with low level of blood oxygen (hypoxemia) during analgo-sedation. Overweight outpatients are often scheduled for colonoscopy usually undergo analgo-sedation. In obese patients, intravenous analgo-sedation often diminish respiratory drive causing hypoxemia. To avoid hypoxemia, low-flow nasal oxygenation (LFNO) of 2-6 L/min is applied via standard nasal catheter to provide maximum 40 % of inspired fraction of oxygen (FiO2). LFNO comprises applying cold and dry oxygen which causes discomfort to nasal mucosa of patient. LFNO is often insufficient to provide satisfying oxygenation. Insufficient oxygenation adds to circulatory instability - heart rate (HR) and blood pressure (BP) disorder.
On the other side, high-flow nasal oxygenation (HFNO) brings 20 to 70 L/min of heated and humidified of O2/air mixture up to 100% FiO2 via specially designed nasal cannula. Heated and humidified O2/air mixture is much more agreeable to patient. HFNO brings noninvasive support to patients' spontaneous breathing by producing continuous positive pressure of 3-7 cmH2O in upper airways consequently enhancing oxygenation.
Investigators intend to analyze effect of HFNO vs. LFNO on oxygen saturation during procedural analgo-sedation for colonoscopy in obese adult patients.
Investigators expect that obese patients with preserved spontaneous breathing, oxygenized by HFNO vs. LFNO, will be less prone to hypoxemia thus more respiratory and circulatory stable during procedural analgo-sedation for colonoscopy.
Obese patients with applied HFNO should longer preserve: normal oxygen saturation, normal level of CO2 and O2, reflecting better respiratory stability. Investigators expect obese participnts to have more stable HR and BP, reflecting improved circulatory stability. There will be less interruption of breathing pattern of obese patients and less necessity for attending anesthesiologist to intervene.
详细描述
Obese patients are often scheduled for colonoscopy under analgo-sedation. Analgo-sedation is characterized by deep conscious sedation and preserved spontaneous breathing. Continuous intravenous application of sedatives favors patients' circulatory stability and application of oxygenation contributes to maintaining adequate patients' oxygenation. Typically, low-flow nasal oxygenation (LFNO) of 2-6 L/min is applied via standard nasal catheter to provide maximum 40% of inspired fraction of oxygen (FiO2) before (preoxygenation), during (procedural oxygenation) and after (postprocedural oxygenation) until patient regains consciousness.
During analgo-sedation obese patients are prone to intervals of bradypnea and hypoventilation. Transitory apnea in obese patients could lead to hypoxemia, hypoxia, hypercapnia and hemodynamic insufficiency despite LFNO application. Fatal outcome may occur, especially at higher risk overweight patients (ASA III class). Respiratory and hemodynamic stability of morbidly obese outpatients during analgo-sedation for endoscopic procedures represent challenge to anesthesiologists. There is no generally accepted protocol of preoxygenation and intraoperative ventilatory management for obese patients. Obese (30<BMI<40 kg/m2, BMI= body mass index) and morbidly obese patients (BMI ≥40 kg/m2) are classified to higher anesthesia risk groups, even if obese patients may not have other comorbidities (30<BMI<40 kg/m2 = ASA II, BMI ≥40 kg/m2 = ASA III).
Partial relaxation of pharyngeal muscles characteristic for analgo-sedation in overweight patients causes prolapse of fatty tissue that partially obstructs pharynx and can cause obstructive sleep apnoea (OSA). Although OSA is not related to obesity, OSA can accompany obesity. Besides perioperatively, hypoxia and bradypnoea episodes occur postoperatively in obese patients, which makes additional observation of obese patients necessary. More frequent hypoxia and bradypnoea during awakening require additional respiratory effort. Ventilation strategies in obese patients are necessary to optimize gas exchange and pulmonary mechanics in order to reduce pulmonary complications.
High-flow nasal oxygenation (HFNO) brings 20 to 70 L/min heated and humidified O2/air mixture up to 100% FiO2 via specially designed, soft nasal cannula. HFNO brings non-invasive support to patients' inspiratory effort by developing 3-7 cmH2O of continuous pressure in upper airway, decreasing it's resistance and dead space. Also, heated and humidified oxygen/air mixture with possibility to bring higher FiO2 adds to better patients' oxygenation preservation and improved patients' comfort during procedure.
AIM of this study is to compare effect of HFNO vs. LFNO during standardized procedure of intravenous analgo-sedation on periprocedural oxygenation maintenance in patients of different weight groups: 18<BMI<30 kg/m2, 30<BMI<40 kg/m2 and BMI ≥40 kg/m2.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Double (Investigator, Outcomes Assessor)
盲法说明
Anesthesiologist who interviews and examines patients scheduled for colonoscopy under analgo-sedation will enroll eligible participants and will offer procedure explanation and possibility to sign uniformed written consent. Unique personal hospital admission number (UPHAN) will be assigned to all eligible participants. After that, they will be randomized to control or intervention group by using random numbers generator. Anesthesiologist who implements anesthesia will receive nontransparent envelope with assigned intervention provided by independent investigator and will not decide which participant will receive LFNO or HFNO. However, attending anesthesiologist and participants will unavoidably be aware of type of oxygenation applied. Investigator who collects data after procedure will be unaware of study protocol and will enter data to formatted database. Participants' data will be noted under UPHAN. Outcome assessors will be unaware of intervention applied.
入排标准
- 年龄范围
- 18 Years 至 75 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •normal weight (18<BMI<30 kg/m2)
- •obese patients (30<BMI<40 kg/m2)
- •morbidly obese patients (BMI≥40 kg/m2)
- •intravenous analgo-sedation
- •elective colonoscopy
- •colorectal tumors.
排除标准
- •emergency colonoscopy
- •diseases of peripheral blood vessels
- •hematological diseases
- •psychiatric diseases
- •sideropenic anemia
- •patients' refusal
- •ongoing chemotherapy or irradiation
- •propofol allergies
- •fentanyl allergies.
结局指标
主要结局
Change of peripheral blood oxygenation (SpO2),
时间窗: Before procedure: 1 minute before start of analgo-sedation and oxygenation, During procedure: 15 minutes from beginning of oxygenation and analgo-sedation, After procedure: 5 minutes after discontinuing oxygenation and analgo-sedation
Peripheral blood saturation (SpO2): Normal range ≥ 92% Acceptable deflection from normal values of peripheral blood saturation (SpO2) significant for hypoxemia is \< 92%, while all values above will be considered normal. Above-mentioned parameter will be observed during procedure so that we can confirm or exclude differences connected with practical application of LFNO and HFNO.
Change of arterial blood saturation (PaO2)
时间窗: Before procedure: 1 minute before start of analgo-sedation and oxygenation, During procedure: 15 minutes from beginning of oxygenation and analgo-sedation, After procedure: 5 minutes after discontinuing oxygenation and analgo-sedation
Partial pressure of oxygen (PaO2): Normal range: ≥11 kPa Partial pressure of oxygen (PaO2), ≥ 11 kPa PaO2 will be considered normal, while all values below are considered significant for hypoxemia. Above-mentioned parameter will be observed during procedure so that we can confirm or exclude differences connected with practical application of LFNO and HFNO.
次要结局
- Change of pH (pH)(Before procedure: 1 minute before start of analgo-sedation and oxygenation, During procedure: 15 minutes from beginning of oxygenation and analgo-sedation, After procedure: 5 minutes after discontinuing oxygenation and analgo-sedation)
- Change of partial pressure of CO2 (PaCO2)(Before procedure: 1 minute before start of analgo-sedation and oxygenation, During procedure: 15 minutes from beginning of oxygenation and analgo-sedation, After procedure: 5 minutes after discontinuing oxygenation and analgo-sedation)
- Change of normopnea (FoB)(From the beginning of oxygenation and analgo-sedation till the end of analgo-sedation and oxygenation - complete procedure duration estimated: 35 minutes)
- Change of frequency of desaturation (fDE)(From the beginning of oxygenation and analgo-sedation till the end of analgo-sedation and oxygenation - complete procedure duration estimated: 35 minutes)
- Change of frequency of bradypnoea during analgo-sedation (fBRP/min)(From the beginning of oxygenation and analgo-sedation till the end of analgo-sedation and oxygenation - complete procedure duration estimated: 35 minutes)
- Change of heart rate (HR/min)(Before procedure: 1 minute before start of analgo-sedation and oxygenation, During procedure: 15 minutes from beginning of oxygenation and analgo-sedation, After procedure: 5 minutes after discontinuing oxygenation and analgo-sedation)
- Change of duration of desaturation (DE/min)(From the beginning of oxygenation and analgo-sedation till the end of analgo-sedation and oxygenation - complete procedure duration estimated: 35 minutes)
- Change of mean arterial pressure (MAP)(Before procedure: 1 minute before start of analgo-sedation and oxygenation, During procedure: 15 minutes from beginning of oxygenation and analgo-sedation, After procedure: 5 minutes after discontinuing oxygenation and analgo-sedation)
研究者
Anita Vukovic
MD, specialist of anesthesiology, reanimatology and intensive care
University of Split, School of Medicine