The Year in Vascular Anesthesia: Selected Highlights From 2018.

This special article is the second in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia that is specifically dedicated to highlights in vascular anesthesiology published in 2018. This review begins with 2 updates in preoperative medicine in the vascular surgery population, including recent publications regarding the management of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers and antiplatelet medications in the perioperative period. The next section focuses on complications related to thoracic endovascular aortic surgery, particularly as technology advances allow for endovascular repair of more complex anatomy. The final section focuses on quality in vascular surgery and evaluates recent publications that examine the safety and feasibility of fast-track endovascular aortic surgery. Even though this is only a sampling of the literature published in 2018 relevant to the cardiovascular anesthesiologist, these themes represent some of the topics most clinically relevant to the perioperative period.

Severity and Duration of Metabolic Acidosis After Deep Hypothermic Circulatory Arrest for Thoracic Aortic Surgery.

OBJECTIVE: To determine the severity, duration, and contributing factors for metabolic acidosis after deep hypothermic circulatory arrest (DHCA). DESIGN: Retrospective observational study. SETTING: University hospital. PATIENTS: Eighty-seven consecutive patients undergoing elective thoracic aortic surgery with DHCA. INTERVENTIONS: Regression analysis was used to test for relationships between the severity of metabolic acidosis and clinical and laboratory variables. MEASUREMENTS AND MAIN RESULTS: Minimum pH averaged 7.27±0.06, with 76 (87%) having a pH<7.35; 55 (63%), a pH<7.30; and 7 (8%), a pH<7.20. The mean duration of metabolic acidosis was 7.9±5.0 hours (range: 0.0 - 26.8), and time to minimum pH after DHCA was 4.3±2.0 hours (1.0 - 10.0 hours). Hyperchloremia contributed to metabolic acidosis in 89% of patients. The severity of metabolic acidosis correlated with maximum lactate (p<0.0001) and hospital length of stay (LOS) (r = 0.22, p<0.05), but not with DHCA time, DHCA temperature, duration of vasoactive infusions, or ICU LOS. Patient BMI was the sole preoperative predictor of the severity of postoperative metabolic acidosis. LIMITATIONS: This retrospective analysis involved short-term clinical outcomes related to pH severity and duration, which indirectly may have included the impact of sodium bicarbonate administration. CONCLUSIONS: Metabolic acidosis was common and severe after DHCA and was attributed to both lactic and hyperchloremic acidosis. DHCA duration and temperature had little impact on the severity of metabolic acidosis. The severity of metabolic acidosis was best predicted by the BMI and had minimal effects on short-term outcomes. Preventing hyperchloremic acidosis has the potential to decrease the severity of metabolic acidosis after DHCA.

Effects of adding statins before surgery on mortality and major morbidity: a meta-analysis.

OBJECTIVE: To re-evaluate the effects of adding a statin before surgery on mortality at 30 days and at 1 year and on major morbidity at 0-30 days. DESIGN: A meta-analysis of parallel, randomized, controlled trials published in English. SETTING: A university-based electronic search. PARTICIPANTS: Adult patients undergoing any type of procedure. INTERVENTION: Adding a statin before a procedure compared to a placebo or no intervention. MEASUREMENTS AND MAIN RESULTS: A search for all randomized controlled trials (RCT) was done in PubMed, Embase, Ovid MEDLINE and the Cochrane Central Register of Controlled Trials in November 2012. The quality of each study was assessed with the Cochrane Collaboration Tools. An I-square ≥ 25% was chosen as the cut-off point for heterogeneity exploration. The search produced 29 trials. Statins reduced the 0-30 days' risk of myocardial infarction: risk ratio (RR) 0.48 (95%CI 0.38, 0.61); I-square 13.2%; p<0.001; number needed-to-treat 17 (14, 24). There were no statistical differences at 0-30 days for stroke RR 0.70 (0.25, 1.95), acute renal insufficiency RR 0.54 (0.26, 1.12) or reoperation RR 1.10 (0.51, 2.38). There was a trend for a reduced mortality at 1 year RR 0.26 (0.06, 1.02); I-square 0%; p = 0.053. The hospital length of stay was slightly decreased with atorvastatin: standardized mean difference (SMD) -0.27 (-0.39, -0.14), p<0.001; fluvastatin SMD -0.95 (-1.56, -0.34), p = 0.002; and rosuvastatin SMD -0.69 (-0.98, -0.40), p<0.001 but not with simvastatin SMD -0.04 (-0.41, 0.48). CONCLUSIONS: Adding a statin before a high risk cardiac procedure reduces the 0-30 days' risk of myocardial infarction.

Intravenous GLP-1 (7-36) amide for prevention of hyperglycemia during cardiac surgery: a randomized, double-blind, placebo-controlled study.

OBJECTIVE: The authors sought to evaluate the efficacy of an intravenous glucagon-like peptide-1 (GLP-1) infusion, compared with placebo, to mitigate intraoperative hyperglycemia. DESIGN: Prospective, double-blinded, randomized, placebo-controlled. SETTING: University hospital. PARTICIPANTS: Diabetic (non-insulin dependent) and non-diabetic patients undergoing elective cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: Patients were randomized in a 1:1 fashion to GLP-1 (7-36) amide infusion (1.5 pmol/kg/min) or placebo. Insulin was administered intraoperatively to both groups per a standardized protocol. MEASUREMENTS AND MAIN RESULTS: A total of 77 patients were included for analysis (GLP-1, n = 37; placebo, n = 40). Mean blood glucose during cardiopulmonary bypass was 127.5 mg/dL and 142.5 mg/dL (p = 0.002) in the GLP-1 and placebo groups, respectively. Mean blood glucose values during the entire intraoperative course were 12.2 mg/dL lower for subjects given GLP-1 (95% CI 2.3, 22, p = 0.015), independent of time. During the period of cardiopulmonary bypass, mean blood glucose values in subjects given GLP-1 were 14.1 mg/dL lower than those who received placebo (95% CI 3.5, 24.8, p = 0.009), independent of time. The incidence of hypoglycemia did not differ significantly between the 2 groups. CONCLUSIONS: Administration of intravenous GLP-1 (7-36) amide to patients undergoing cardiac surgery significantly reduced their plasma glucose levels intraoperatively and may represent a novel therapeutic strategy to prevent perioperative hyperglycemia.

Advancing extubation time for cardiac surgery patients using lean work design.

BACKGROUND: Early extubation in select cardiac surgery patients reduces tracheal intubation times, intensive care unit length of stay, and hospital length of stay. While there is good evidence in the literature to support early extubation, there is very little published research that describes how to study and redesign processes of care to increase early extubation rates. OBJECTIVE: To improve rates of early extubation by redesigning patient care processes using Lean principles to remove barriers to desired care and facilitate early extubation with guideline management. DESIGN: Retrospective data analysis. SETTING: Sixteen-bed intensive care unit in a mid-sized, academic community hospital. PATIENTS: Four hundred four patients undergoing coronary artery bypass graft surgery, aortic valve replacement, or mitral valve replacement/repair. INTERVENTION: The process of care for cardiac surgery patients, beginning with the immediate preoperative period and ending with extubation in the postoperative period, was analyzed using Lean methodologies. A value stream analysis was performed to identify waste in the process, and root causes for the largest sources of waste were identified. Hypothermia on admission to the intensive care unit, prolonged weaning using arterial blood gas results, hypertension management with pain medications and sedation medications, and delays in obtaining equipment were the primary reasons early extubation was delayed. Process redesign using Lean work design principles was implemented to eliminate these issues. MEASUREMENTS: The rate of patients being extubated in fewer than 6 hours and length of intubation. RESULTS: One hundred ninety-five pre-intervention subjects were compared with 171 post-intervention subjects. The pre- and post- groups did not differ in demographic predictors (Table 1). The intervention predicted extubation in<6 hours (pre-intervention 27% versus post-intervention 50%, p = 0.0001). Age, renal failure, and gender also predicted whether intubation occurred within 6 hours. The median length of intubation was lower post-intervention (pre-intervention 9.7 v post-intervention 6.1 hours, p = 0.0019) LIMITATIONS: The effect of this nonrandomized intervention could be due to other factors associated with a different care epoch. CONCLUSIONS: The closely planned, coordinated, and integrated care paradigm dramatically increased the likelihood of extubation within 6 hours of arrival in the SICU.

Cardiac arrest associated with reperfusion of the liver during transplantation: incidence and proposal for a management algorithm.

Cardiac arrest associated with reperfusion of the liver allograft in a euvolemic patient is a rare but potentially devastating event. There are few case series describing experience with this complication and no published management protocols guiding treatment. This article is a retrospective case series of patients experiencing post-reperfusion intraoperative cardiac arrest between 1997 and 2011. Among 1581 liver transplants, 16 (1%) patients experienced post-reperfusion cardiac arrest. Among patients with intraoperative arrests, 14 (88%) patients required open cardiac massage. Seven (44%) were placed on cardiopulmonary bypass (CPB) when cardiac activity failed to adequately recover. Placement on CPB reversed cardiac pump failure and established a perfusing rhythm in six of seven (86%) recipients, leading to one of seven (14%) intraoperative mortality. Recovery of myocardial function was associated with low early survival with only 3/7 (43%) patients who underwent CPB surviving until discharge. Among all patients who survived the perioperative period, one-yr survival was 70% (N = 7), and five-yr survival was 50% (N = 5). Cardiac arrest during liver transplantation is associated with a poor prognosis during the perioperative period. In patients who do not recover cardiac activity after standard resuscitative measures, progression to physiologic support with systemic anticoagulation and CPB may allow correction of electrolyte derangements, maintenance of cerebral perfusion, and myocardial recovery.

ß-blocking agents for surgery: influence on mortality and major outcomes. A meta-analysis.

OBJECTIVE: To re-evaluate the effects of perioperative beta-blockade on mortality and major outcomes after surgery. DESIGN: A meta-analysis of parallel randomized, controlled trials published in English. SETTING: A university-based electronic search. PARTICIPANTS: Patients undergoing surgery. INTERVENTIONS: Two interventions were evaluated: (1) Stopping or continuing a ß-blocker in patients on long-term ß-blocker therapy; and (2) Adding a ß-blocker for the perioperative period. MEASUREMENTS AND MAIN RESULTS: Stopping a ß-blocker before the surgery did not change the risk of myocardial infarction (3 studies including 97 patients): risk ratio (RR), 1.08 (95% confidence interval 0.30, 3.95); I(2), 0%. Adding a ß-blocker reduced the risk of death at 1 year: RR, 0.56 (0.31, 0.99); I(2), 0%; p = 0.046; number needed to treat 28 (19, 369) (4 studies with 781 patients). Adding a ß-blocker reduced the 0-to-30 day risk of myocardial infarction: RR, 0.65 (0.47, 0.88); I(2), 12.9%; p = 0.006 (15 studies with 12,224 patients), but increased the risk of a stroke: RR, 2.18 (1.40, 3.38); I(2), 0%; p = 0.001 (8 studies with 11,737 patients); number needed to harm 177 (512, 88). CONCLUSIONS: ß-blockers reduced the 1-year risk of death, and this effect seemed greater than the risk of inducing a stroke.

Validation study of Doppler-derived transmitral valve gradients compared to near simultaneously obtained directly measured catheter gradients immediately after mitral valve repair surgery.

OBJECTIVE: To evaluate the accuracy of Doppler-derived transmitral valve gradients immediately after mitral valve repair by comparing them with near simultaneously obtained direct catheter gradients. DESIGN: A prospective study. SETTING: A tertiary care medical center. PARTICIPANTS: Twenty elective adult surgical patients presenting for mitral valve repair surgery. METHODS: Mitral valve surgery proceeded in standard fashion except for the use of a smaller than usual left ventricular vent catheter (Medtronic DLP 10 French left heart vent catheter). After completion of the mitral valve repair and subsequent cardiac de-airing, the patient was weaned from cardiopulmonary bypass. Immediately after separation, the study period began. Near simultaneous transmitral Doppler gradients were obtained with directly measured catheter gradients via the vent catheter. RESULTS: While the mean peak gradient difference of 1.1 mmHg was small (p-value 0.18, 95% CI: -0.54 to 2.73 mmHg), the correlation between Doppler and catheter gradient measurements (Pearson correlation coefficient r = 0.54, p = 0.055) only approached statistical significance due to the large variance associated with the small sample size. In all patients with a peak gradient greater than 10 mmHg (4 of the 20 patients), overestimation of catheter gradients by Doppler occurred, with two showing a 62% to 73% discrepancy. In these two cases, there was also evidence for elevated left ventricular end-diastolic pressure (LVEDP) along with high transmitral blood flow velocities. CONCLUSION: Doppler-derived transmitral gradients provide a simple, safe, and reliable measure of the true physiologic transmitral valve gradient. At the same time, it is important to recognize that significant Doppler over-estimation of catheter gradients may occur in patients with elevated Doppler transmitral velocities. The causes of these overestimations are unknown. They may be related to technical recording errors. They may also be related to an inherent weakness in Doppler technology--its inability to account for any distal recovery of pressure, which in a select group of patients could be significant.

Carotid endarterectomy plus medical therapy or medical therapy alone for carotid artery stenosis in symptomatic or asymptomatic patients: a meta-analysis.

OBJECTIVE: The purpose of this study was to compare carotid endarterectomy (CEA) plus medical therapy (MT) with MT alone for symptomatic and asymptomatic patients suffering from carotid artery stenosis in terms of long-term stroke/death rate. DESIGN: A meta-analysis of parallel randomized, controlled trials (RCTs) (blind or open) published in English. SETTING: A university-based electronic search. PARTICIPANTS: Patients suffering from carotid artery stenosis symptomatic or not. INTERVENTIONS: Patients were subjected to CEA plus MT or MT alone. MEASUREMENTS AND MAIN RESULTS: For asymptomatic patients, 6 RCTs comprising 5,733 patients (CEA = 2,853 and MT = 2,880) were included. CEA did not affect the stroke/death risk for asymptomatic patients (risk ratio [RR] = 0.93; 95% confidence interval [CI], 0.84 to 1.02; I(2) = 0%; p = 0.14). For symptomatic patients, 2 RCTs were included. They had 5,627 patients (CEA = 3,069 and MT = 2,558) of whom 2,295 patients (CEA = 1,213; MT = 1,082) had severe stenosis (North American Symptomatic Carotid Endarterectomy Trial [NASCET] technique ≥50% and European Carotid Surgery Trial technique ≥70%). CEA decreased the stroke/death risk only for patients with severe stenosis (RR = 0.69; 95% CI, 0.59-0.81; p < 0.001 [random effects model]; I(2) = 0% on the odds ratio and 17% on the RR [benefit or harm side]; number needed to treat = 11 [95% CI, 8-17]). CONCLUSIONS: CEA is helpful for recently symptomatic patients with carotid artery stenosis ≥50% (NASCET technique) but adds no benefit in terms of stroke/death for asymptomatic patients.

Recovery of consciousness and cognition after general anesthesia in humans.

Understanding how the brain recovers from unconsciousness can inform neurobiological theories of consciousness and guide clinical investigation. To address this question, we conducted a multicenter study of 60 healthy humans, half of whom received general anesthesia for 3 hr and half of whom served as awake controls. We administered a battery of neurocognitive tests and recorded electroencephalography to assess cortical dynamics. We hypothesized that recovery of consciousness and cognition is an extended process, with differential recovery of cognitive functions that would commence with return of responsiveness and end with return of executive function, mediated by prefrontal cortex. We found that, just prior to the recovery of consciousness, frontal-parietal dynamics returned to baseline. Consistent with our hypothesis, cognitive reconstitution after anesthesia evolved over time. Contrary to our hypothesis, executive function returned first. Early engagement of prefrontal cortex in recovery of consciousness and cognition is consistent with global neuronal workspace theory.

Anesthesia is a state of reversable, controlled unconsciousness. It has enabled countless medical procedures. But it also serves as a tool for scientists to study how the brain regains consciousness after disruptions such as sleep, coma or medical procedures requiring general anesthesia. It is still unclear how exactly the brain regains consciousness, and less so, why some patients do not recover normally after general anesthesia or fail to recover from brain injury. To find out more, Mashour et al. studied the patterns of reemerging consciousness and cognitive function in 30 healthy adults who underwent general anesthesia for three hours. While the volunteers were under anesthesia, their brain activity was measured with an EEG; and their sleep-wake activity was measured before and after the experiment. Each participant took part in a series of cognitive tests designed to measure the reaction speed, memory and other functions before receiving anesthesia, right after the return of consciousness, and then every 30 minutes thereafter. Thirty healthy volunteers who did not have anesthesia also completed the scans and tests as a comparison group. The experiments showed that certain normal EEG patterns resumed just before a person wakes up from anesthesia. The return of thinking abilities was an extended, multistep process, but volunteers recovered their cognitive abilities to nearly the same level as the volunteers within three hours of being deeply anesthetized. Mashour et al. also unexpectedly found that abstract problem-solving resumes early in the process, while other functions such as reaction time and attention took longer to recover. This makes sense from an evolutionary perspective. Sleep leaves individuals vulnerable. Quick evaluation and decision-making skills would be key to respond to a threat upon waking. The experiments confirm that the front of the brain, which handles thinking and decision-making, was especially active around the time of recovery. This suggests that therapies targeting this part of the brain may help people who experience loss of consciousness after a brain injury or have difficulties waking up after anesthesia. Moreover, disorders of cognition, such as delirium, in the days following surgery may be caused by factors other than the lingering effects of anesthetic drugs on the brain.

Noninvasive ventilation immediately after extubation improves lung function in morbidly obese patients with obstructive sleep apnea undergoing laparoscopic bariatric surgery.

BACKGROUND: Noninvasive positive pressure ventilation (NIPPV) may improve postoperative lung function and reduce postoperative complications in patients undergoing abdominal surgery. The purpose of our study was to determine whether the timing of postoperative NIPPV affects lung function 1 day postoperatively. METHODS: Forty morbidly obese patients with known obstructive sleep apnea undergoing laparoscopic bariatric surgery with standardized anesthesia care were randomly assigned to receive NIPPV immediately after tracheal extubation (immediate group) or supplemental oxygen (standard group). All patients had continuous positive airway pressure initiated 30 minutes after extubation in the postanesthesia care unit (PACU) via identical noninvasive ventilators. Spirometry was performed by a blinded observer in the perioperative holding area 1 hour after admission to the PACU and 1 day postoperatively. The primary outcome was the change in forced vital capacity (FVC) from baseline to 24 hours (FVC baseline-FVC 24 hours). RESULTS: Forty patients, 20 in each group, were enrolled in the study. Forced expiratory volume in 1 second, FVC, and peak expiratory flow rate were significantly reduced in both groups from perioperative values throughout the study. At 24 hours, the intervention group had lost only 0.7 L FVC, versus 1.3 L for the intervention group (P = 0.0005). An analysis of covariance confirmed this and indicated that the immediate postoperative NIPPV better preserved spirometric function at 1 and 24 hours postoperatively. Specifically, the differences in the primary outcome were statistically significant. CONCLUSIONS: NIPPV given immediately after extubation significantly improves spirometric lung function at 1 hour and 1 day postoperatively, compared with continuous positive airway pressure started in the PACU, in morbidly obese patients with obstructive sleep apnea undergoing laparoscopic bariatric surgery.

Management of the difficult airway in the COVID-19 pandemic: Illustrative complex head and neck cancer scenario.

BACKGROUND: This case highlights challenges in the assessment and management of the "difficult airway" patient in the SARS-CoV-2 (COVID-19) pandemic era. METHODS: A 60-year-old male with history of recent transoral robotic surgery resection, free flap reconstruction, and tracheostomy for p16+ squamous cell carcinoma presented with stridor and dyspnea 1 month after decannulation. Careful planning by a multidisciplinary team allowed for appropriate staffing and personal protective equipment, preparations for emergency airway management, evaluation via nasopharyngolaryngoscopy, and COVID testing. The patient was found to be COVID negative and underwent imaging which revealed new pulmonary nodules and a tracheal lesion. RESULTS: The patient was safely transorally intubated in the operating room. The tracheal lesion was removed endoscopically and tracheostomy was avoided. CONCLUSIONS: This case highlights the importance of careful and collaborative decision making for the management of head and neck cancer and other "difficult airway" patients during the COVID-19 epidemic.

Risk of Persistent Opioid Use following Major Surgery in Matched Samples of Patients with and without Cancer.

BACKGROUND: The opioid crisis has reached epidemic proportions, yet risk of persistent opioid use following curative intent surgery for cancer and factors influencing this risk are not well understood. METHODS: We used electronic health record data from 3,901 adult patients who received a prescription for an opioid analgesic related to hysterectomy or large bowel surgery from January 1, 2013, through June 30, 2018. Patients with and without a cancer diagnosis were matched on the basis of demographic, clinical, and procedural variables and compared for persistent opioid use. RESULTS: Cancer diagnosis was associated with greater risk for persistent opioid use after hysterectomy [18.9% vs. 9.6%; adjusted OR (aOR), 2.26; 95% confidence interval (CI), 1.38-3.69; P = 0.001], but not after large bowel surgery (28.3% vs. 24.1%; aOR 1.25; 95% CI, 0.97-1.59; P = 0.09). In the cancer hysterectomy cohort, persistent opioid use was associated with cancer stage (increased rates among those with stage III cancer compared with stage I) and use of neoadjuvant or adjuvant chemotherapy; however, these factors were not associated with persistent opioid use in the large bowel cohort. CONCLUSIONS: Patients with cancer may have an increased risk of persistent opioid use following hysterectomy. IMPACT: Risks and benefits of opioid analgesia for surgical pain among patients with cancer undergoing hysterectomy should be carefully considered.

Continuous positive airway pressure via the Boussignac system immediately after extubation improves lung function in morbidly obese patients with obstructive sleep apnea undergoing laparoscopic bariatric surgery.

BACKGROUND: Morbidly obese patients are at elevated risk of perioperative pulmonary complications, including airway obstruction and atelectasis. Continuous positive airway pressure may improve postoperative lung mechanics and reduce postoperative complications in patients undergoing abdominal surgery. METHODS: Forty morbidly obese patients with known obstructive sleep apnea undergoing laproscopic bariatric surgery with standardized anesthesia care were randomly assigned to receive continuous positive airway pressure via the Boussignac system immediately after extubation (Boussignac group) or supplemental oxygen (standard care group). All subjects had continuous positive airway pressure initiated 30 min after extubation in the postanesthesia care unit via identical noninvasive ventilators. The primary outcome was the relative reduction in forced vital capacity from baseline to 24 h after extubation. RESULTS: Forty patients were enrolled into the study, 20 into each group. There were no significant differences in baseline characteristics between the groups. The intervention predicted less reduction in all measured lung functions: forced expiratory volume in 1 s (coefficient 0.37, SE 0.13, P = 0.003, CI 0.13-0.62), forced vital capacity (coefficient 0.39, SE 0.14, P = 0.006, CI 0.11-0.66), and peak expiratory flow rate (coefficient 0.82, SE 0.31, P = 0.008, CI 0.21-0.1.4). CONCLUSIONS: Administration of continuous positive airway pressure immediately after extubation maintains spirometric lung function at 24 h after laparoscopic bariatric surgery better than continuous positive airway pressure started in the postanesthesia care unit.

Obstructive sleep apnea is not a risk factor for difficult intubation in morbidly obese patients.

BACKGROUND: Morbid obesity (MO), obstructive sleep apnea (OSA), and neck circumference (NC) are widely believed to be independent risk factors for difficult tracheal intubation. In this study, we sought to determine whether these factors were associated with increased risk of difficult intubation in patients undergoing bariatric surgery. The predictive factors tested were OSA and its severity, as determined by apnea-hypopnea index (AHI), gender, NC, and body mass index (BMI). METHODS: All sequentially enrolled MO patients underwent preoperative polysomnography. Severity of OSA was quantified using AHI and the American Society of Anesthesiologists' OSA severity scale. All patients had a standardized anesthetic that included positioning in the "ramped position" for direct laryngoscopy. RESULTS: One hundred eighty consecutive patients were recruited, 140 women and 40 men. The incidence of OSA was 68%. The mean BMI was 49.4 kg/m(2). The mean AHI was 31.3 (range, 0-135). All the patients' tracheas were intubated successfully without the aid of rescue airways by anesthesiology residents. Six patients required three or more intubation attempts, a difficult intubation rate of 3.3%. There was an 8.3% incidence of difficult laryngoscopy, defined as a Cormack and Lehane Grade 3 or 4 view. There was no relationship between NC and difficult intubation (odds ratio 1.02, 95% confidence interval 0.93-1.1), between the diagnosis of OSA and difficult intubation (P = 0.09), or between BMI and difficult intubation (odds ratio 0.99, 95% confidence interval 0.92-1.06, P = 0.8). There was no relationship between number of intubation attempts and BMI (P = 0.8), AHI (P = 0.82), or NC (P = 0.3). Mallampati Grade III or more predicted difficult intubation (P = 0.02), as did male gender (P = 0.02). Finally, there was no relationship between Cormack and Lehane grade and BMI (P = 0.88), AHI (P = 0.93), or OSA (P = 0.6). Increasing NC was associated with difficult laryngoscopy but not difficult intubation (P = 0.02). CONCLUSIONS: In MO patients undergoing bariatric surgery in the "ramped position," there was no relationship between the presence and severity of OSA, BMI, or NC and difficulty of intubation or laryngoscopy grade. Only a Mallampati score of 3 or 4 or male gender predicted difficult intubation.