Duration of safe apnea in patients with morbid obesity during passive oxygenation using high-flow nasal insufflation versus regular flow nasal insufflation, a randomized trial
“…Using our definition of apnoea onset, the maximum apnoea time in these earlier studies was 10.5 min 14 and, subsequently, one trial has extended this to 14 min. 15 There have been no studies of comparable size with the exception of one, studying obese patients, in which the maximum apnoea time was 6 min. 16 In the FM group, a lower proportion tolerated apnoea without desaturation, suggesting that HFNO improves the efficiency of apnoeic oxygenation.…”
Background: Obesity is a risk factor for airway-related incidents during anaesthesia. High-flow nasal oxygen has been advocated to improve safety in high-risk groups, but its effectiveness in the obese population is uncertain. This study compared the effect of high-flow nasal oxygen and low-flow facemask oxygen delivery on duration of apnoea in morbidly obese patients. Methods: Morbidly obese patients undergoing bariatric surgery were randomly allocated to receive either high-flow nasal (70 L min À1 ) or facemask (15 L min À1 ) oxygen. After induction of anaesthesia, the patients were apnoeic for 18 min or until peripheral oxygen saturation decreased to 92%. Results: Eighty patients were studied (41 High-Flow Nasal Oxygen, 39 Facemask). The median apnoea time was 18 min in both the High-Flow Nasal Oxygen (IQR 18e18 min) and the Facemask (inter-quartile range [IQR], 4.1e18 min) groups. Five patients in the High-Flow Nasal Oxygen group and 14 patients in the Facemask group desaturated to 92% within 18 min. The risk of desaturation was significantly lower in the High-Flow Nasal Oxygen group (hazard ratio¼0.27; 95% confidence interval [CI], 0.11e0.65; P¼0.007). Conclusions: In experienced hands, apnoeic oxygenation is possible in morbidly obese patients, and oxygen desaturation did not occur for 18 min in the majority of patients, whether oxygen delivery was high-flow nasal or low-flow facemask. High-flow nasal oxygen may reduce desaturation risk compared with facemask oxygen. Desaturation risk is a more clinically relevant outcome than duration of apnoea. Individual physiological factors are likely to be the primary determinant of risk rather than method of oxygen delivery. Clinical trial registration: NCT03428256.
“…Using our definition of apnoea onset, the maximum apnoea time in these earlier studies was 10.5 min 14 and, subsequently, one trial has extended this to 14 min. 15 There have been no studies of comparable size with the exception of one, studying obese patients, in which the maximum apnoea time was 6 min. 16 In the FM group, a lower proportion tolerated apnoea without desaturation, suggesting that HFNO improves the efficiency of apnoeic oxygenation.…”
Background: Obesity is a risk factor for airway-related incidents during anaesthesia. High-flow nasal oxygen has been advocated to improve safety in high-risk groups, but its effectiveness in the obese population is uncertain. This study compared the effect of high-flow nasal oxygen and low-flow facemask oxygen delivery on duration of apnoea in morbidly obese patients. Methods: Morbidly obese patients undergoing bariatric surgery were randomly allocated to receive either high-flow nasal (70 L min À1 ) or facemask (15 L min À1 ) oxygen. After induction of anaesthesia, the patients were apnoeic for 18 min or until peripheral oxygen saturation decreased to 92%. Results: Eighty patients were studied (41 High-Flow Nasal Oxygen, 39 Facemask). The median apnoea time was 18 min in both the High-Flow Nasal Oxygen (IQR 18e18 min) and the Facemask (inter-quartile range [IQR], 4.1e18 min) groups. Five patients in the High-Flow Nasal Oxygen group and 14 patients in the Facemask group desaturated to 92% within 18 min. The risk of desaturation was significantly lower in the High-Flow Nasal Oxygen group (hazard ratio¼0.27; 95% confidence interval [CI], 0.11e0.65; P¼0.007). Conclusions: In experienced hands, apnoeic oxygenation is possible in morbidly obese patients, and oxygen desaturation did not occur for 18 min in the majority of patients, whether oxygen delivery was high-flow nasal or low-flow facemask. High-flow nasal oxygen may reduce desaturation risk compared with facemask oxygen. Desaturation risk is a more clinically relevant outcome than duration of apnoea. Individual physiological factors are likely to be the primary determinant of risk rather than method of oxygen delivery. Clinical trial registration: NCT03428256.
“…The mean BMI in the enrolled patients varied from 33 to 52 kg/m 2 . The proportion of patients with obstructive sleep apnea (OSA) was between 12.5 and 72.5% in five trials 23 – 27 , while five studies did not provide this information 28 – 32 . Of the ten studies, two assessed the beneficial effects of HFNO on postoperative pulmonary parameters in patients receiving laparoscopic bariatric surgery 23 , 24 , while eight studies evaluated the efficacy of HFNO against peri-procedural hypoxemia or oxygenation status during anesthesia induction (six trials) 26 – 30 , 32 , tracheal intubation in the intensive care unit (one trial) 31 , and colonoscopy under deep sedation (one trial) 25 .…”
Section: Resultsmentioning
confidence: 99%
“…In the HFNO groups, the flow rate ranged from 50 to 120 L/min. In the control groups receiving COT/NIV, mask oxygenation was adopted in four studies 23 , 24 , 27 , 29 , while NIV and nasal cannula oxygenation were used in other four 26 , 30 – 32 and two 25 , 28 RCTs, respectively. Figure 1 PRISMA flow diagram of study selection for the current meta-analysis.…”
This meta-analysis aimed at investigating the efficacy of high-flow nasal oxygenation (HFNO) against hypoxemia in patients with obesity compared with conventional oxygenation therapy and non-invasive ventilation. Databases were searched from inception to August 2021. Studies involving peri- or post-procedural use of HFNO were included. The primary outcome was risk of hypoxemia, while the secondary outcomes included status of oxygenation and carbon dioxide elimination. Ten randomized controlled trials (RCTs) were included. We found that HFNO prolonged the safe apnea time at induction compared to control group [mean difference (MD) = 73.88 s, p = 0.0004; 2 RCTs] with no difference in risk of peri-procedural hypoxemia [relative risk (RR) = 0.91, p = 0.64; 4 RCTs], minimum SpO2 (MD = 0.09%, p = 0.95; 4 RCTs), PaO2 (MD = − 8.13 mmHg, p = 0.86; 3 RCTs), PaCO2 (MD = − 6.71%, p = 0.2; 2 RCTs), EtCO2 (MD = − 0.28 mmHg, p = 0.8; 4 RCTs) between the two groups. HFNO also did not improve postprocedural PaO2/FiO2 ratio (MD = 41.76, p = 0.58; 2 RCTs) and PaCO2 (MD = − 2.68 mmHg, p = 0.07; 2 RCTs). This meta-analysis demonstrated that the use of HFNO may be associated with a longer safe apnea time without beneficial impact on the risk of hypoxemia, oxygenation, and CO2 elimination in patients with obesity. The limited number of trials warranted further large-scale studies to support our findings.
“…While there are many different techniques and methods available to assist in the process of intubation, apneic oxygenation is a method that can be used to increase the time between induction and the onset of hypoxia (the safe apnea time). [ 5 48 49 ] The safe apnea time is inversely proportional to BMI and thus strategies to increase the safe apnea time can be useful in patients with obesity since physiological changes predispose them to rapid desaturation during induction. [ 5 7 50 51 52 ] Apneic oxygen increases the safe apnea time by supplying oxygen to the alveoli even when the patient is not being ventilated due to a negative pressure differential in the alveoli created by decreased carbon dioxide return to the alveoli during apnea.…”
Section: Literature Reviewmentioning
confidence: 99%
“…[ 50 ] However, in patients with morbid obesity, high-flow nasal insufflation of oxygen (120 L/min) was not found to increase the duration of safe apnea compared to standard nasal apneic oxygenation (10 L/min). [ 48 ]…”
Airway management in patients with obesity remains a complex and evolving topic that is becoming more pertinent given the increasing prevalence of obesity and bariatric surgery worldwide. Obesity is associated with increased morbidity and mortality secondary to anesthetic complications, especially related to airway management. Preoperative assessment is especially vital for the bariatric patient so that potential predictors for a difficult airway can be identified. There are several airway management strategies and techniques for the bariatric population that may help reduce postoperative pulmonary complications. This review aims to discuss assessment of the airway, ideal patient positioning, intubation techniques and devices, apneic oxygenation, optimal ventilation strategies, and extubation and post-anesthesia care.
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