Degree of obesity is not associated with more than one intubation attempt: a large centre experience. Br J Anaesth. 2018;120:1110-1116. [PMID: 29661388 DOI: 10.1016/j.bja.2018.01.019]

Structured Routine Use of Styletubation for Oro-Tracheal Intubation in Obese Patients Undergoing Bariatric Surgeries-A Case Series Report

The aim of this case series report is to provide a new topical view of styletubation (video intubating stylet technique) in obese patients undergoing bariatric surgeries. In contrast to various conventional direct laryngoscopes (DLs), videolaryngoscopes (VLs) have been applied in such obese populations with potentially difficult airway complications. The safety and effectiveness of VLs have been repeatedly studied, and the superiority of VLs has then been observed in and advocated for routine use. In this article, among our vast use experiences with styletubation (more than 54,998 patients since 2016) for first-line routine tracheal intubation, we present the unique experience to apply the styletubation technique in obese patients undergoing bariatric surgery. Consistent with the experiences applied in other patient populations, we found the styletubation technique itself to be swift (the time to intubate from 5 s to 24 s), smooth (first-attempt success rate: 100%), safe (no airway complications), and easy (high subjective satisfaction). The learning curve is steep, but competency can be enhanced if technical pitfalls can be avoided. We, therefore, propose that the styletubation technique can be feasibly and routinely applied as a first-line airway modality in obese patients undergoing bariatric surgery.

Anesthesia considerations for pediatric metabolic and bariatric surgery

Childhood obesity is a rapidly growing global health issue, linked to significant lifelong morbidity and mortality. Its impact on various organ systems increases perioperative complications. Obesity treatment in children and adolescents involves lifestyle, dietary, and behavioral modifications, as well as pharmacologic interventions that targets hormonal, metabolic, and neurochemical abnormalities. Metabolic and bariatric surgery, proven safe and effective for adults with severe obesity (class 2 or higher), is now being recommended for adolescents. Key anesthetic considerations for these surgeries include preoperative optimization, advanced airway management, targeted ventilation strategies, and opioid-sparing analgesic regimens. Comprehensive presurgical evaluations must address co-morbid conditions such as hypertension, obstructive sleep apnea, asthma, and impaired glycemic control. Preoperative management should also consider the effects of antiobesity medications on gastric emptying and hemodynamic stability. Ventilation strategies should prevent atelectasis while avoiding barotrauma, and drug dosages must be adjusted for altered pharmacokinetics due to increased adipose tissue. Employing enhanced recovery after surgery protocols may reduce perioperative complications, shorten postsurgical stays, and improve outcomes.

Video Laryngoscopy vs Direct Laryngoscopy for Endotracheal Intubation in the Operating Room: A Cluster Randomized Clinical Trial

Importance

Endotracheal tubes are typically inserted in the operating room using direct laryngoscopy. Video laryngoscopy has been reported to improve airway visualization; however, whether improved visualization reduces intubation attempts in surgical patients is unclear.

Objective

To determine whether the number of intubation attempts per surgical procedure is lower when initial laryngoscopy is performed using video laryngoscopy or direct laryngoscopy.

Design, Setting, and Participants

Cluster randomized multiple crossover clinical trial conducted at a single US academic hospital. Patients were adults aged 18 years or older having elective or emergent cardiac, thoracic, or vascular surgical procedures who required single-lumen endotracheal intubation for general anesthesia. Patients were enrolled from March 30, 2021, to December 31, 2022. Data analysis was based on intention to treat.

Interventions

Two sets of 11 operating rooms were randomized on a 1-week basis to perform hyperangulated video laryngoscopy or direct laryngoscopy for the initial intubation attempt.

Main Outcomes and Measures

The primary outcome was the number of operating room intubation attempts per surgical procedure. Secondary outcomes were intubation failure, defined as the responsible clinician switching to an alternative laryngoscopy device for any reason at any time, or by more than 3 intubation attempts, and a composite of airway and dental injuries.

Results

Among 8429 surgical procedures in 7736 patients, the median patient age was 66 (IQR, 56-73) years, 35% (2950) were women, and 85% (7135) had elective surgical procedures. More than 1 intubation attempt was required in 77 of 4413 surgical procedures (1.7%) randomized to receive video laryngoscopy vs 306 of 4016 surgical procedures (7.6%) randomized to receive direct laryngoscopy, with an estimated proportional odds ratio for the number of intubation attempts of 0.20 (95% CI, 0.14-0.28; P < .001). Intubation failure occurred in 12 of 4413 surgical procedures (0.27%) using video laryngoscopy vs 161 of 4016 surgical procedures (4.0%) using direct laryngoscopy (relative risk, 0.06; 95% CI, 0.03-0.14; P < .001) with an unadjusted absolute risk difference of -3.7% (95% CI, -4.4% to -3.2%). Airway and dental injuries did not differ significantly between video laryngoscopy (41 injuries [0.93%]) vs direct laryngoscopy (42 injuries [1.1%]).

Conclusion and Relevance

In this study among adults having surgical procedures who required single-lumen endotracheal intubation for general anesthesia, hyperangulated video laryngoscopy decreased the number of attempts needed to achieve endotracheal intubation compared with direct laryngoscopy at a single academic medical center in the US. Results suggest that video laryngoscopy may be a preferable approach for intubating patients undergoing surgical procedures.

Trial Registration

ClinicalTrials.gov Identifier: NCT04701762.

Association Between Age- and Sex-Specific Body Mass Index Percentile and Multiple Intubation Attempts: A Retrospective Cohort Analysis

BACKGROUND

Obesity distorts airways and slightly complicates intubations in adults, but whether obesity complicates pediatric intubations remains unclear. We, therefore, tested the primary hypothesis that increasing age- and sex-specific body mass index (BMI) percentile is associated with difficult intubation, defined as >1 intubation attempt.

METHODS

We conducted a retrospective analysis of pediatric patients between 2 and 18 years of age who had noncardiac surgery with oral endotracheal intubation. We assessed the association between BMI percentile and difficult intubation, defined as >1 intubation attempt, using a confounder-adjusted multivariable logistic regression model. Secondarily, we assessed whether the main association depended on preoperative substantial airway abnormality status or age group.

RESULTS

A total of 9339 patients were included in the analysis. Median [quartiles] age- and sex-specific BMI percentile was 70 [33, 93], and 492 (5.3%) patients had difficult intubation. There was no apparent association between age- and sex-specific BMI percentile and difficult intubation. The estimated odds ratio (OR) for having difficult intubation for a 10-unit increase in BMI percentile was 0.98 (95% confidence interval [CI], 0.95-1.005) and was consistent across the 3 age groups of early childhood, middle childhood, and early adolescence (interaction P = .53). Patients with preoperative substantial airway abnormalities had lower odds of difficult intubation per 10-unit increase in BMI percentile, with OR (95% CI) of 0.83 (0.70-0.98), P = .01.

CONCLUSIONS

Age- and sex-specific BMI percentile was not associated with difficult intubation in children between 2 and 18 years of age. As in adults, obesity in children does not much complicate intubation.

Preoperative Assessment of a Patient Undergoing Bariatric Surgery

Over the past few decades, obesity rates in the United States have risen drastically, and with this, there has been a rising demand for bariatric surgery. As such, anesthesiologists need to be familiar with the challenges presented by patients seeking bariatric surgery. Obesity causes pathophysiologic changes which may affect decision-making during the management of these patients. Patients seeking bariatric surgery also have a long, prescribed preoperative course that offers anesthesiologists the opportunity to be involved earlier during the pre-surgical evaluation and optimization process.

Adverse Tracheal Intubation Events in Critically Ill Underweight and Obese Children: Retrospective Study of the National Emergency Airway for Children Registry (2013-2020)

OBJECTIVES

Extremes of patient body mass index are associated with difficult intubation and increased morbidity in adults. We aimed to determine the association between being underweight or obese with adverse airway outcomes, including adverse tracheal intubation (TI)-associated events (TIAEs) and/or severe peri-intubation hypoxemia (pulse oximetry oxygen saturation < 80%) in critically ill children.

DESIGN/SETTING

Retrospective cohort using the National Emergency Airway for Children registry dataset of 2013-2020.

PATIENTS

Critically ill children, 0 to 17 years old, undergoing TI in PICUs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Registry data from 24,342 patients who underwent TI between 2013 and 2020 were analyzed. Patients were categorized using the Centers for Disease Control and Prevention weight-for-age chart: normal weight (5th-84th percentile) 57.1%, underweight (< 5th percentile) 27.5%, overweight (85th to < 95th percentile) 7.2%, and obese (≥ 95th percentile) 8.2%. Underweight was most common in infants (34%); obesity was most common in children older than 8 years old (15.1%). Underweight patients more often had oxygenation and ventilation failure (34.0%, 36.2%, respectively) as the indication for TI and a history of difficult airway (16.7%). Apneic oxygenation was used more often in overweight and obese patients (19.1%, 19.6%) than in underweight or normal weight patients (14.1%, 17.1%; p < 0.001). TIAEs and/or hypoxemia occurred more often in underweight (27.1%) and obese (24.3%) patients ( p < 0.001). TI in underweight children was associated with greater odds of adverse airway outcome compared with normal weight children after adjusting for potential confounders (underweight: adjusted odds ratio [aOR], 1.09; 95% CI, 1.01-1.18; p = 0.016). Both underweight and obesity were associated with hypoxemia after adjusting for covariates and site clustering (underweight: aOR, 1.11; 95% CI, 1.02-1.21; p = 0.01 and obesity: aOR, 1.22; 95% CI, 1.07-1.39; p = 0.002).

CONCLUSIONS

In underweight and obese children compared with normal weight children, procedures around the timing of TI are associated with greater odds of adverse airway events.

Styletubation in Bariatric Surgery: A Case Report

Direct laryngoscopes and videolaryngoscopes are the dominant endotracheal intubation tools. The styletubation technique (using a video-assisted intubating stylet) has shown its advantages in terms of short intubation time, high success rate, less required stimulation, and operator satisfaction. The learning curve can be steep but is easily overcome if technical pitfalls are avoided. Conditions that make styletubation challenging include secretions/blood, short/stiff neck, restricted mouth opening and cervical spine mobility, anatomical abnormalities over head and neck regions, obesity, etc. In this clinical report, we present the effectiveness and efficiency of the routine use of the styletubation for tracheal intubation in a super-super-obese patient (BMI 103 kg/m2) undergoing bariatric surgery with laparoscopic sleeve gastrectomy.

The lumbar subcutaneous fat gradient in spinal anesthesia seen for morbidly obese patient with pre-procedure ultrasonography - A case report

It has been reported that pre-procedure ultrasonography rises the success rate of spinal anesthesia in obese patients. In this article, we performed spinal anesthesia for morbidly obese patient with pre-procedure ultrasonography. And recognizing the lumbar subcutaneous fat gradient in morbidly obese patient was the key to success. A cesarean section was scheduled for a primigravida in her 30 s with BMI 61 kg/m2. The lumbar spine was not palpable. Pre-procedure ultrasonography revealed lumbar subcutaneous tissue getting thicker caudally in the sagittal view. Considering this fact, we adjusted the puncture site and succeeded. Postoperative complications were not observed. The pre-procedure ultrasonography is effective even in morbidly obese patients. It is important to recognize the lumbar subcutaneous fat gradient, the so-called back fat slope, for spinal anesthesia in obese patients.

Association between body mass index and difficult intubation with a double lumen tube: A retrospective cohort study

STUDY OBJECTIVE

Obesity, defined by the World Health Organization as body mass index (BMI) ≥ 30.0 kg/m², is associated with adverse outcomes and challenges during surgery. Difficulties during endotracheal intubation, occur in 3-8% of procedures and are among the principal causes of anesthetic-related morbidity and mortality. Endotracheal intubation can be challenging in obese patients due to an array of anatomic and physiologic factors. Double lumen tubes (DLTs), the most commonly used airway technique to facilitate anatomic isolation of the lungs for one lung ventilation. However, DLTs can be difficult to properly position and are also more likely to cause airway injuries and bleeding when compared to conventional single lumen tubes. We investigated the association between BMI and difficult tracheal DLT intubation.

DESIGN

Retrospective cohort study.

SETTING

Operating room.

PATIENTS

We analyzed electronic records of adults having cardiac and thoracic surgery requiring general anesthesia and endotracheal intubation with DLT at the Cleveland Clinic between 2008 and 2021.

MEASUREMENTS

BMI, preoperative airway abnormalities and difficult intubation, defined as more than one intubation attempt, was assessed using multivariable logistic regression.

MAIN RESULTS

Among 8641 analyzed anesthetics requiring DLT, 1459 (17%) were difficult intubations. After adjusting for confounders, each 5 kg/m² increase in BMI was associated with a marginal increase of difficult intubation, odds ratio (OR) 1.06 (95% Confidence Interval [CI]: 1.002, 1.11; P = 0.040). Difficult intubation was not associated with airway abnormalities, estimated OR 0.85 (95% CI: 0.62, 1.17; P = 0.321). There was no interaction between known airway abnormalities and BMI (P = 0.894).

CONCLUSIONS

Difficult intubations with DLT remain common, but BMI is a weak predictor thereof. For example, an increase in BMI from 20 to 40 kg/m² corresponds to an increase in average absolute risk for difficult intubation from 16 to 19%, which probably is not clinically meaningful.

2022 American Society of Anesthesiologists Practice Guidelines for Management of the Difficult Airway

The American Society of Anesthesiologists; All India Difficult Airway Association; European Airway Management Society; European Society of Anaesthesiology and Intensive Care; Italian Society of Anesthesiology, Analgesia, Resuscitation and Intensive Care; Learning, Teaching and Investigation Difficult Airway Group; Society for Airway Management; Society for Ambulatory Anesthesia; Society for Head and Neck Anesthesia; Society for Pediatric Anesthesia; Society of Critical Care Anesthesiologists; and the Trauma Anesthesiology Society present an updated report of the Practice Guidelines for Management of the Difficult Airway.

Perioperative challenges in management of diabetic patients undergoing non-cardiac surgery

Prediabetes and diabetes are important disease processes which have several perioperative implications. About one third of the United States population is considered to have prediabetes. The prevalence in surgical patients is even higher. This is due to the associated micro and macrovascular complications of diabetes that result in the need for subsequent surgical procedures. A careful preoperative evaluation of diabetic patients and patients at risk for prediabetes is essential to reduce perioperative mortality and morbidity. This preoperative evaluation involves an optimization of preoperative comorbidities. It also includes optimization of antidiabetic medication regimens, as the avoidance of unintentional hypoglycemic and hyperglycemic episodes during the perioperative period is crucial. The focus of the perioperative management is to ensure euglycemia and thus improve postoperative outcomes. Therefore, prolonged preoperative fasting should be avoided and close monitoring of blood glucose should be initiated and continued throughout surgery. This can be accomplished with either analysis in blood gas samples, venous phlebotomy or point-of-care testing. Although capillary and arterial whole blood glucose do not meet standard guidelines for glucose testing, they can still be used to guide insulin dosing in the operating room. Intraoperative glycemic control goals may vary slightly in different protocols but overall the guidelines suggest a glucose range in the operating room should be between 140 mg/dL to 180 mg/dL. When hyperglycemia is detected in the operating room, blood glucose management may be initiated with subcutaneous rapid-acting insulin, with intravenous infusion or boluses of regular insulin. Fluid and electrolyte management are other perioperative challenges. Notably diabetic ketoacidosis and hyperglycemic hyperosmolar nonketotic state are the two most serious acute metabolic complications of diabetes that must be recognized early and treated.

Multivariate Analysis of the Failure Risk of First Tracheal Intubation Attempt in a Population of Patients Scheduled for Bariatric Surgery

BACKGROUND

Airway management during the administration of anesthesia to patients undergoing bariatric surgery is challenging. The goal is to avoid multiple intubation attempts because the risk of complications increases with the number of attempts. The objective of this study was to determine the failed first intubation attempt rate, as well as variables associated with this failure, in patients undergoing bariatric surgery.

METHODS

We enrolled patients scheduled for bariatric surgery in this prospective, observational, single-center study. We determined predictive criteria for difficult intubation at the preoperative anesthesia consultation. All patients were evaluated for obstructive sleep apnea by polygraphy. The primary study endpoint was a failed first intubation attempt.

RESULTS

We enrolled 519 patients between December 2012 and January 2015. The cohort consisted of 425 women (82%), with a median (interquartile range [IQR]) age of 39 (30-50) years and a body mass index of 42 (39-46) kg/m². The first intubation attempt failed in 60 patients, with an incidence rate of 11.5% (95% confidence interval [CI], 8.8-14.2%). We included nine variables in the final multivariate model. Two variables were associated with failed first intubation attempt: male sex (odds ratio [OR] [95% CI], 6.9% [2.5-18.7%]) and Mallampati score 3-4 (OR [95% CI], 2.2% [1.0-4.7%]).

CONCLUSIONS

In this morbidly obese population, the first intubation attempt failed in 11.5% of patients, and the risk factors for failure were male sex and a high Mallampati score.

Airway events in obese vs. non-obese elective surgical patients: a cross-sectional observational study

Obesity is an increasingly prevalent comorbidity within the UK population. The aim of this study was to determine the proportion of obese patients in an elective surgical population. The second aim was to determine the choice of airway equipment and incidence of airway events in obese vs. non-obese patients. We conducted a cross-sectional observational study over two 24-h periods in March 2018 across 39 hospitals in the greater London area. Data were collected regarding 1874 patients. The incidence of obesity was 32% in the study population compared with 26% in the general UK population (p < 0.0001). Minor airway events were defined as: desaturation to S_p O₂ < 90%; failed mask ventilation; supraglottic airway device problem; aspiration; airway trauma and difficult intubation; or recognised oesophageal intubation. Major airway events were defined as: unrecognised oesophageal intubation; a 'cannot intubate cannot oxygenate' emergency; the need for unplanned front-of-neck airway; cardiac arrest; or unplanned intensive care unit admission due to an airway event. In total, 89 minor and two major airway events were recorded. Obese patients were more likely to experience a minor airway event (RR 2.39, 95%CI 1.60-3.57), the most common being desaturation (S_p O₂ < 90%). The use of a supraglottic airway device in obese vs. non-obese patients was associated with increased airway events (RR 3.46 [1.88-6.40]). Tracheal intubation vs. supraglottic airway device use increased with obesity class but was not associated with a decrease in airway events (RR 0.90 [0.53-1.55]). Our data suggest that obesity is more common in the elective surgical vs. general population and minor airway events are more common in obese vs. non-obese elective patients.

Preoperative X-ray C2C6AR is applicable for prediction of difficult laryngoscopy in patients with cervical spondylosis

BACKGROUND

Airway management is one of the most important techniques in anesthesia practice and inappropriate airway management is related with airway injury, brain hypoxia, and even death. The patients with cervical spondylosis are often confronted with difficult laryngoscopy who are more prone to appear difficult airway, so it is important to figure out valuable predictors of difficult laryngoscopy in these patients.

METHODS

We randomly enrolled 270 patients undergoing elective cervical spine surgery and analyzed the cervical mobility data in predicting difficult laryngoscopy. The preoperative X-ray radiological indicators were measured by an attending radiologist. Cormack-Lehane scales were assessed during intubation, and patients with a class III or IV view were assigned to the difficult laryngoscopy group.

RESULTS

Univariate analysis showed that the hyomental distance (HMD, the distance between the hyoid bone and the tip of the chin) and the hyomental distance ratio (HMDR, the ratio between HMD in the extension position and the one in the neutral position) might not be suitable indicators in patients with cervical spondylosis. Binary multivariate logistic regression (backward-Wald) analyses identified two independent correlative factors from the cervical mobility indicators that correlated best as a predictor of difficult laryngoscopy: modified Mallampati test (MMT) and C₂C₆AR (the ratio of the angle between a line passing through the bottom of the second cervical vertebra and a line passing through the bottom of the sixth cervical vertebra in the extension position and the one in the neutral position). The odds ratio (OR) and 95 % CI were 2.292(1.093-4.803) and 0.493 (0.306-0.793), respectively. C₂C₆AR exhibited the largest area under the curve (0.714; 95 % CI 0.633-0.794).

CONCLUSIONS

C₂C₆AR based on preoperative X-ray images may be the most accurate predictor of cervical mobility indicators for difficult laryngoscopy in patients with cervical spondylosis.

TRIAL REGISTRATION

The study was registered at the Chinese Clinical Trial Registry ( http://www.chictr.org.cn ; identifier: ChiCTR-ROC-16,008,598) on June 6, 2016.

Evaluation of super-obesity and super-super-obesity as risk factors for difficult intubation in patients undergoing bariatric surgery

BACKGROUND

Super-obesity is a serious disorder which requires bariatric surgery. The association of super-obesity and difficult intubation was not adequately established.

OBJECTIVES

To determine if super-obesity and super-super-obesity are associated with difficult intubation or not.

SETTING

University Hospital.

METHODS

A cohort of obese patients scheduled for bariatric surgery was prospectively recruited. Super-obesity and super-super-obesity were defined as body mass index ≥50 kg/m² and 60 kg/m², respectively. Intubation difficulty was assessed by 2 methods: (1) intubation difficulty scale; (2) number of intubation attempts. Risk factors for difficult intubation were recorded. Univariate and multivariate analysis for risk factors for difficult intubation and difficult mask ventilation were performed.

RESULTS

A total of 658 patients were enrolled in the study including 205 (31%) super-obese and 52 (8%) super-super-obese patients. Ninety-nine (15%) patients required more than 1 intubation attempt, while 215 (33%) patients had intubation difficulty scale ≥5. Ninety-four (14.4%) patients had mask ventilation of moderate difficulty, while only 2 (.3%) patients needed 2-person ventilation. The independent risk factors for difficult intubation using the two stated definitions were STOP-Bang and Mallampati score values. The independent risk factors for mask ventilation of moderate difficulty were STOP-Bang score, Mallampati score, and limited neck extension.

CONCLUSION

Within obese patients, neither super-obesity nor super-super-obesity was associated with difficult intubation or difficult mask ventilation. High STOP-Bang and Mallampati score are the independent factors for difficult intubation.

Macintosh Videolaryngoscope for Intubation in the Operating Room: A Comparative Quality Improvement Project

BACKGROUND

"Macintosh"-videolaryngoscopes (VLs) are VLs that allow both direct and indirect laryngoscopy for intubation. We describe the decision-making and implementation-processes that our hospital used regarding the choice of device. We compared the performances of 4 Macintosh-VLs both in direct and indirect laryngoscopy.

METHODS

A quality-improvement-project for airway management aiming at implementing Macintosh-VL for all intubation procedures performed in the operating room, involving 4 Macintosh-VLs (McGrath-Mac, C-MAC-S, C-MAC-S-Pocket-Monitor [PM], and APA). Three consecutive steps were described: (1) direct laryngoscopy with Macintosh-VL, (2) indirect laryngoscopy with Macintosh-VL (intubation attempt with Macintosh-style blade in case of Cormack I or II), (3) intubation attempt with hyperangulated blade in case of Cormack III/IV or failure of Macintosh-style blade. The main end point was the need to move to step III and use a hyperangulated blade. A mixed-effects multivariable logistic regression analysis was performed to compare devices on the main end point while considering site as a random effect. Comparison of means was performed using analysis of variance and Tukey's test for multiple comparisons (number of laryngoscopy attempts, numeric rate scale [NRS] difficulty of intubation and NRS user-friendliness). Comparison of percentages was performed using a χ2 test for the need to move to step III and a Kruskal-Wallis test for the quality of image (bad, passable, good, very good, excellent). A P value ≤.008 was considered statistically significant.

RESULTS

From May to September 2017, 589 patients were included. Using the McGrath-Mac (22/180 [12%]) was associated with less use of hyperangulated blade than using the C-MAC-S (39/132 [30%], odds ratio [OR] [99.2% confidence interval {CI}] 0.34 [0.16-0.77], P = .0005), the APA (35/138 [25%], OR [99.2% CI] 0.42 [0.19-0.93]; P = .004), but not the C-MAC-S-PM (29/139 [21%], OR [99.2% CI] 0.53 [0.23-1.2]; P = .04).Overall, the number of intubation attempts was significantly lower using the McGrath Mac than the C-MAC-S or the C-MAC-S-PMVLs. Subjective appreciation of intubation difficulty and user-friendliness of the devices showed respectively lower and higher NRS scores for the McGrath-Mac compared to the other devices, whereas subjective assessment of image quality showed higher quality for the C-MAC-S and C-MAC-S-PM compared to the APA or McGrath-Mac.

CONCLUSIONS

Among 4 single-use Macintosh-VLs, glottic visualization in direct and indirect laryngoscopy with the Macintosh-style blade was significantly improved with the McGrath-Mac compared to other Macintosh-VLs, leading to a less frequent need to resort to the hyperangulated blade and reduced overall number of intubation attempts.

McGrath Video Laryngoscope Versus Macintosh Direct Laryngoscopy for Intubation of Morbidly Obese Patients: A Randomized Trial

BACKGROUND

Two-thirds of the US population is considered obese and about 8% morbidly obese. Obese patients may present a unique challenge to anesthesia clinicians in airway management. Videolaryngoscopes may provide better airway visualization, which theoretically improves intubation success. However, previous work in morbidly obese patients was limited. We therefore tested the primary hypothesis that the use of McGrath video laryngoscope improves visualization of the vocal cords versus Macintosh direct laryngoscopy (Teleflex, Morrisville, NC) in morbidly obese patients.

METHODS

We enrolled 130 surgical patients, aged 18-99 years, with a body mass index ≥40 kg/m and American Society of Anaesthesiologists (ASA) physical status I-III. Patients were randomly allocated 1:1-stratified for patient's body mass index ≥50 kg/m-to McGrath video laryngoscope versus direct laryngoscopy with a Macintosh blade. The study groups were compared on glottis visualization, defined as improved Cormack and Lehane classification, with proportional odds logistic regression model.

RESULTS

McGrath video laryngoscope provided significantly better glottis visualization than Macintosh direct laryngoscopy with an estimated odds ratio of 4.6 (95% confidence interval [CI], 2.2-9.8; P < .01). We did not observe any evidence that number of intubation attempts and failed intubations increased or decreased.

CONCLUSIONS

McGrath video laryngoscope improves glottis visualization versus Macintosh direct laryngoscopy in morbidly obese patients. Large clinical trials are needed to determine whether improved airway visualization with videolaryngoscopy reduces intubation attempts and failures.

Comparison of the new flexible tip bougie catheter and standard bougie stylet for tracheal intubation by anesthesiologists in different difficult airway scenarios: a randomized crossover trial

Background

Incidence of difficult endotracheal intubation ranges between 3 and 10%. Bougies have been recommended as an airway adjunct for difficult intubation, but reported success rates are variable. A new generation flexible tip bougie appears promising but was not investigated so far. We therefore compared the new flexible tip with a standard bougie in simulated normal and difficult airway scenarios, and used by experienced anesthesiologists.

Methods

We conducted a observational, randomized, cross-over simulation study. Following standardized training, experienced anesthesiologists performed endotracheal intubation using a Macintosh blade and one of the bougies in six different airway scenarios in a randomized sequence: normal airway, tongue edema, pharyngeal obstruction, manual cervical inline stabilization, cervical collar stabilization, cervical collar stabilization and pharyngeal obstruction. Overall success rate with a maximum of 3 intubation attempts was the primary endpoint. Secondary endpoints included number of intubation attempts, time to intubation and dental compression.

Results

Thirty-two anesthesiologist participated in this study between January 2019 and May 2019. Overall success rate was similar for the flexible tip bougie and the standard bougie. The flexible tip bougie tended to need less intubation attempts in more difficult airway scenarios. Time to intubation was less if using the flexible tip bougie compared to the standard bougie. Reduced severity of dental compression was noted for the flexible tip bougie in difficult airway scenarios except cervical collar stabilization.

Conclusion

In this simulation study of normal and difficult airways scenarios, overall success rate was similar for the flexible tip and standard bougie. Especially in more difficult airway scenarios, less intubation attempts, and less optimization maneuvers were needed if using the flexible tip bougie.

Trial registration

clinicaltrials.gov Identifier: NCT03733158. 7th November 2018.

Patient factors associated with difficult flexible bronchoscopic intubation under general anesthesia: a prospective observational study

PURPOSE

Patient characteristics associated with difficult tracheal intubation using a flexible bronchoscope (FB) under general anesthesia have not been prospectively evaluated. This observational study aimed to identify demographic and morphologic factors associated with difficult FB intubation.

METHODS

We recruited 420 adult elective surgery patients undergoing tracheal intubation during general anesthesia. Patients characteristics were recorded including age, sex, weight, height, body mass index, American Society of Anesthesiologists physical status, history of snoring, obstructive sleep apnea, Mallampati score, upper lip bite test score, neck circumference and skinfold thickness, maximal neck flexion and extension angles, absence of teeth, Cormack and Lehane grade, presence of blood or secretions during intubation, as well as the inter-incisor, thyromental, sternothyroid, and manubriomental distances. The time (duration) needed to complete intubation (primary endpoint) and the number of attempts needed were correlated with these patient characteristics in a multivariable analysis.

RESULTS

Intubation was successful on the first attempt in 409/420 patients (97%). Seven patients (1.7%) needed more than one attempt. Failure to intubate with the FB occurred in four patients (1%). A correlation was found between intubation duration and visibility impaired by secretions or blood (P < 0.001), higher neck skinfold thickness (P < 0.001), and larger endotracheal tube diameter (relative to a constant 5.5 mm FB; P < 0.001).

CONCLUSIONS

The presence of secretions or blood that impair FB glottic visualization, a larger diameter endotracheal tube on the same size FB, as well as higher neck skinfold thickness may prolong the duration of FB intubation under general anesthesia.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT02769819); registered 5 May, 2016.

[The obese patient and acute respiratory failure, a challenge for intensive care]

As a result of the constantly increasing epidemic of obesity, it has become a common problem in the intensive care unit. Morbid obesity has numerous consequences for the respiratory system. It affects both respiratory mechanics and pulmonary gas exchange, and dramatically impacts on the patient's management and outcome. With the potential for causing devastating respiratory complications, the particular anatomical and physiological characteristics of the respiratory system of the morbidly obese subject should be carefully taken into consideration. The present article reviews the management of obese patients in respiratory failure, from noninvasive ventilation to tracheostomy, including postural and technical issues, and explains the physiologically based ventilatory strategy both for NIV and invasive mechanical ventilation up to the weaning from the ventilatory support.

Recent advances in anesthesia of the obese patient

The anesthetic management of an obese patient can be challenging because of the altered anatomy and physiology associated with obesity. In this article, I review the recent medical literature and highlight some of the controversies in the airway management and drug dosing of morbidly obese patients.