Plasma Metanephrines Yield Fewer False-Positive Results Than Urine Metanephrines in Patients With Obstructive Sleep Apnea.

CONTEXT: Obstructive sleep apnea (OSA) is associated with increased nocturnal sympathetic activity. In OSA patients, elevations in metanephrines may lead to false-positive tests when evaluating for pheochromocytoma or paraganglioma (PPGL). OBJECTIVE: To evaluate whether morning plasma metanephrines would lead to fewer false-positive results than 24-hour urinary metanephrines in OSA patients. METHODS: Patients undergoing polysomnography for suspected OSA were recruited. Plasma free and 24-hour urinary metanephrines were measured by HPLC-MS/MS. Patients with elevated levels had repeat measurements, abdominal imaging, and follow-up to diagnose or exclude a PPGL. RESULTS: Seventy-six patients completed polysomnography and biochemical testing; 68 (89.5%) patients had OSA, of whom 19 (27.9%) had elevated plasma and/or urinary metanephrines. On follow-up, one patient had a bladder paraganglioma, while PPGL was excluded in the remaining patients. OSA patients had more false-positive urinary metanephrines (17 of 67, 25.4%) than plasma metanephrines (2 of 67, 3.0%), P < .01, and this was more common in severe OSA (13 of 34, 38.2%), compared to moderate/mild OSA (4 of 33, 12.1%), P < .01. Both plasma and urinary metanephrines decreased after treatment with continuous positive airway pressure. On multivariable analysis, severe OSA, obesity, and family history of hypertension were positive predictors for false-positive urinary metanephrines in patients with suspected OSA. CONCLUSION: In OSA patients, plasma metanephrines are less likely to yield false-positive results for the diagnosis of PPGL than 24-hour urinary metanephrines. In patients with suspected OSA, obesity, or a family history of hypertension, plasma metanephrines may be the preferred first-line test to avoid unnecessary anxiety or follow-up.

Efficacy of high flow nasal cannula as an alternative to continuous positive airway pressure therapy in surgical patients with suspected moderate to severe obstructive sleep apnea.

PURPOSE: To compare the efficacy of High flow nasal cannula (HFNC) as an alternative to Continuous Positive Airway Pressure (CPAP) therapy on the first postoperative night in patients with suspected moderate to severe obstructive sleep apnea (OSA). METHODS: This is randomised controlled trial conducted in a tertiary hospital which included elective surgical patients with STOP-BANG score of 5 and above. Forty patients were randomised into one of the four postoperative treatment groups: CPAP, or HFNC at three different flow rates (20 L/min, 30 L/min and 40 L/min). The primary outcome measured was the number of recorded drops in baseline SpO2 of >4%. Secondary outcomes measured included the need for supplemental oxygen or other interventions and the total number of hours of usage of the device. Patient satisfaction, preference for device and reasons for their preference were also collected. RESULTS: CPAP was used for a significantly fewer number of hours compared to HFNC (at all flow rates) during the first postoperative night. There was no significant difference in the primary outcome or in the requirement for other interventions between the four treatment groups. 73.3% of patients in the HFNC group preferred the use of HFNC to the use of CPAP. Reasons for user preference for HFNC include device comfort, ease of use, reduced noise levels and perception of efficacy. CONCLUSIONS: HFNC could be an useful alternative to CPAP as it is not inferior to CPAP in the perioperative management of OSA and is better tolerated.

Postoperative cardiorespiratory complications and continuous positive airway pressure efficacy in obese patients undergoing noncardiac surgery.

BACKGROUND AND AIMS: One in six Singaporeans has obstructive sleep apnoea (OSA) due to obesity compounded by inherent craniofacial features. We assessed the incidence of cardiopulmonary complications and the effectiveness of continuous positive airway pressure (CPAP) therapy in minimising such complications within an obese population. METHODS: A retrospective study of elective noncardiac surgical patients with a body mass index ≥32 kg/m2 was conducted. Patients at moderate to severe risk of OSA were offered CPAP therapy. CPAP therapy adherence, postoperative complications, length of hospital stay, and type of anaesthesia were analysed. RESULTS: In total, 1400 patients comprising 174 with low risk of OSA (L-OSA) and 1226 with moderate to high risk of OSA were included. Of these, 332 were started on CPAP therapy (C-OSA) while 894 declined CPAP use (R-OSA). There were 10 (0.05%) cardiac events - one (0.6%) in the L-OSA group, six (0.6%) in the R-OSA group and three (0.9%) in the C-OSA group. There were 37 (2.6%) respiratory events - 2 (1.1%) in the L-OSA group, 23 (2.6%) in the R-OSA group, and 12 (3.6%) in the C-OSA group. Multivariate analysis showed no statistical significance in CPAP therapy minimising cardiac (P = 0.147) and respiratory (P = 0.255) complications, when analysed by intention-to-treat. CPAP therapy adherence was 13.6 and 10.2% pre- and postoperatively, respectively. When analysed per protocol, none of the nine patients compliant with both pre- and postoperative CPAP therapy developed cardiopulmonary complications. CONCLUSIONS: Amongst patients with moderate to severe risk of OSA, those who were compliant to perioperative CPAP therapy demonstrated a reduction in cardiopulmonary complications.

Comparing treatment effects of a convenient vibratory positional device to CPAP in positional OSA: a crossover randomised controlled trial.

OBJECTIVES: Up to 77% of patients with obstructive sleep apnoea (OSA) have positional OSA (POSA) but traditional positional therapy (PT) methods have failed as they were poorly tolerated. New convenient vibratory PT devices have been invented but while recent studies suggest high treatment efficacy and adherence, there are no published data comparing these devices directly with continuous positive airway pressure (CPAP). Our objective is to evaluate if a convenient vibratory PT device is non-inferior to CPAP in POSA treatment. METHODS: In this crossover randomised controlled trial, we enrolled patients with POSA with significant daytime sleepiness (Epworth Sleepiness Scale (ESS)≥10). POSA diagnosis was based on: (1) total Apnoea/Hypopnoea Index (AHI)>10/hour and non-supine AHI<10/hour (2) supine AHI≥2 × non-supine AHI. Patients used their initial allocated devices (PT or CPAP) for 8 weeks before crossing to the alternative intervention after a 1 week washout. The primary aim is to measure changes in ESS between the two treatments. Secondary outcomes include sleep study parameters and patient treatment preference (ClinicalTrials.gov: NCT03125512). RESULTS: 40 patients completed the trial between April 2017 and December 2018. Difference in ESS after 8 weeks of device use (PT minus CPAP) was 2.0 (95% CI 0.68 to 3.32), exceeding our predetermined non-inferiority margin of 1.5. AHI on CPAP was lower than with PT (4.0±3.2 vs 13.0±13.8 events/hour, respectively, p=0.001), although both were lower than at baseline. Time spent supine was significantly lower with PT than CPAP (p<0.001). 60% of patients preferred CPAP, 20% preferred PT, while 20% preferred neither device. CONCLUSIONS: The non-inferiority ESS endpoint for PT compared with CPAP was not met and the results were inconclusive. Future trials with larger sample sizes or in less symptomatic patients are warranted to provide further insight into the role of these new vibratory PT devices.

PEAK PlasmaBlade versus monopolar electrocautery tonsillectomy in adults: A prospective double-blinded randomized controlled trial.

OBJECTIVE: To evaluate the efficacy and compare postoperative pain and recovery following PEAK PlasmaBlade and monopolar electrocautery tonsillectomy in adults. STUDY DESIGN: Prospective double-blinded randomized controlled trial. METHODS: Fifty-eight patients were recruited and randomized into 2 groups: PEAK PlasmaBlade (n = 29) or monopolar electrocautery (n = 29) tonsillectomy. Postoperative pain, complications, patient satisfaction, number of tablets of analgesia taken and days taken to return to soft diet, normal diet, normal activities and achieve pain-free swallowing were compared and analysed, with the aid of a pain diary given to patients. Statistical analysis was performed with SPSS 13.0 with statistical significance set at P < 0.05. RESULTS: Patients in the PEAK PlasmaBlade group were able to achieve pain-free swallowing in a shorter time compared to the electrocautery group (13.28 versus 15.76 days, P = 0.035). Patients were also more satisfied with PEAK PlasmaBlade tonsillectomy (P = 0.046). No significant differences in the incidence of postoperative haemorrhage, daily visual analog score for pain, number of tablets of analgesia taken and time taken to return to soft diet, normal diet and activities were seen for both groups. CONCLUSIONS: This study showed that PEAK PlasmaBlade tonsillectomy has a faster recovery period in terms of time taken to achieve pain-free swallowing and may offer advantages when compared to monopolar electrocautery tonsillectomy. LEVEL OF EVIDENCE: 1b.

Adherence to Continuous Positive Airway Pressure therapy in Singaporean patients with Obstructive Sleep Apnea.

PURPOSE: To investigate the rates of Continuous Positive Airway Pressure (CPAP) uptake and adherence amongst Singaporean patients diagnosed with Obstructive Sleep Apnea (OSA), and to evaluate factors correlated with CPAP uptake and adherence. STUDY DESIGN: Retrospective review of medical records. METHODS: Medical records were reviewed for baseline demographics, daytime sleepiness, presence of nasal symptoms and OSA severity, initial treatment choice, the rate of CPAP treatment uptake and CPAP adherence at 1 and 12 months. RESULTS: 2160 patients were diagnosed with OSA within the 5-year period (2011-2015). 463 (21.4%) had mild OSA, 583 (27.0%) had moderate OSA and 1114 (51.6%) had severe OSA. For initial therapy, 751 (34.8%) patients opted for a 1-month CPAP trial, 288 (13.3%) patients chose surgery upfront, 291 (13.5%) patients chose adjunctive treatments (weight loss, positional therapy, dental appliance, intranasal steroid spray for allergic rhinitis) and 830 (38.4%) patients rejected all forms of treatment. 337 out of 751 patients (44.9%) were adherent to CPAP therapy during the 1 month trial. 381 out of 751 (50.7%) patients took up CPAP therapy following the trial period, of which 299 out of 381 (78.5%) patients were adherent to CPAP therapy at 1 year. CPAP adherence during the 1-month trial was a predictor for eventual CPAP treatment uptake and CPAP adherence at 1 year (p < 0.001). Age (p < 0.001), BMI (p < 0.001) and normal ESS (p = 0.01) were predictors of treatment rejection. 24 patients underwent upper airway surgery during their first year of using CPAP. 21 out of the 24 patients (87.5%) were adherent to CPAP at 1 year after undergoing surgery. These patients had a higher rate of CPAP adherence compared to the overall cohort (87.5% versus 78.5%), but this was not statistically significant (p > 0.05). CONCLUSION: Singaporean patients who accept CPAP therapy after an initial 1-month CPAP trial will generally be adherent to CPAP therapy. Initial patterns of CPAP usage are predictive of long term CPAP adherence. However, there is a high rate of CPAP treatment rejection both at the time of diagnosis and after the CPAP trial. Upper airway surgery in selected patients may improve CPAP adherence.

Robotic Obstructive Sleep Apnea Surgery.

Since the first report of the use of the da Vinci robotic system (Intuitive Surgical, Sunnyvale, CA, USA) in transoral robotic tongue base reduction for obstructive sleep apnea (OSA) was published in 2010, this surgical tool and technique has been used worldwide for the resection of tongue base tissue in the multilevel surgical treatment of OSA. The combined knowledge of the published literature on its use has enlightened sleep surgeons worldwide on this new yet evolving surgical tool. Here we will discuss the use of the da Vinci robotic system in the treatment of OSA, the pertinent surgical anatomy for a safe surgical procedure, the primary and secondary outcomes to expect in the multilevel and primary use of this technology in treating the tongue base, the predictors for success or failure, and the complications associated with this technique. We will also compare this technology with other existing techniques for treating OSA and look to the future for other similar technologies in this application.

Obstructive sleep apnoea and Type 2 diabetes mellitus: are they connected?

Obstructive sleep apnoea (OSA), a sleep-related breathing condition, is diagnosed based on a patient's apnoea-hypopnea index from a sleep study, and the presence or absence of symptoms. Diabetes mellitus (DM) and OSA share a significant common risk factor, obesity, with all three conditions contributing to the risk of developing cardiovascular diseases. The pathophysiological links between OSA and DM are still unclear, but intermittent hypoxia may be an important mechanism. More awareness of the possible link between OSA and DM is needed, given their increasing prevalence locally and worldwide. Continuous positive airway pressure is the standard treatment for OSA, while weight loss through dietary and lifestyle modifications is important to holistically manage patients with either condition. There is currently insufficient evidence to support the benefits of screening every diabetic patient for OSA. However, diabetic patients with symptoms suggestive of OSA should be referred to a sleep specialist for further evaluation.

Effects of tonsillectomy on sleep study parameters in adult patients with obstructive sleep apnea--a prospective study.

OBJECTIVE: The objective of this study is to evaluate the efficacy of tonsillectomy in reduction of respiratory disturbance index (RDI) and other sleep study parameters in patients with obstructive sleep apnea (OSA). METHODS: This study involves 34 adults with OSA and Friedman grade 3 or 4 tonsils. All 34 patients were treated with tonsillectomy, as the only surgical treatment for OSA from 2007 to 2011. Pre- and postoperative polysomnography were performed in all these patients. RESULTS: Prior to tonsillectomy, 21 patients had severe, 9 had moderate, and 4 had mild OSA. Surgical response rate (defined as 50% or more reduction in apnea-hypopnea index (AHI) and a postoperative AHI of less than 20) was 71.4% among patients with severe OSA, 77.7% among patients with moderate, and 75% among patients with mild. Among all the 34 patients, there was a reduction of 24.6 (p = 0.000) in the RDI postoperatively. In our sub-analysis, we arbitrarily divided the patients into three groups: patients with RDI less than 30, patients with RDI between 30 and 60, and patients with RDI above 60. It showed that, in the group with RDI >60, an average reduction of RDI by 57.6 (p = 0.000) was achieved and was the greatest reduction in RDI. CONCLUSIONS: Tonsillectomy alone may be considered as an effective first line surgical procedure in the treatment of OSA in selected patients. Patients with Friedman grade 3 or 4 tonsils may be considered for tonsillectomy as the initial surgical procedure, reserving other upper airway procedures at a later stage if necessary.

Hyoid expansion with titanium plate and screw: a human cadaveric study using computer-assisted airway measurement.

IMPORTANCE: Hyoid expansion with suspension can potentially increase the upper airway at the hypopharyngeal level, benefitting patients with sleep-related breathing disorder. OBJECTIVES: To document the effect of hyoid expansion using titanium plate and screw on retrolingual hypopharyngeal airway dimension and to compare the airway dimension after isolated hyoid expansion with hyoid expansion + hyomandibular suspension. DESIGN: Anatomical cadaveric dissection study. SETTING: This study was performed in a laboratory setting using human cadavers. INTERVENTION: This is an anatomical feasibility study of hyoid expansion using titanium plate and screw on 10 cadaveric human heads and necks. The hyoid bone is trifractured with bony cuts made just medial to the lesser cornu. The freed hyoid body and lateral segments are expanded and stabilized to a titanium adaptation plate. Computer-assisted airway measurement (CAM) was used to measure the airway dimension at the hypopharynx at the level of the tongue base before and after the hyoid expansion. The expanded hyoid bone was then suspended to the mandible, and the airway dimension was measured again with CAM. MAIN OUTCOMES AND MEASURES: Airway dimension after isolated hyoid expansion with hyoid expansion with hyomandibular suspension. RESULTS Hyoid expansion with titanium plate and screw resulted in statistical significant increase in the retrolingual hypopharyngeal airway space in all of the 10 human cadavers. The mean (SD) increase in retroglossal area was 33.4 (13.2) mm² (P < .005) (range, 6.0-58.7 mm²). Hyoid expansion with hyomandibular suspension resulted in a greater degree of airway enlargement. The mean (SD) increase in retroglossal area was 99.4 (15.0) mm² (P < .005) (range, 81.9-127.5 mm²). CONCLUSIONS AND RELEVANCE: The retrolingual hypopharyngeal airway space increased with hyoid expansion using titanium plate and screw in our human cadaveric study, measured using CAM. The degree of increase is further augmented with hyomandibular suspension.

Is impedance pH monitoring superior to the conventional 24-h pH meter in the evaluation of patients with laryngorespiratory symptoms suspected to be due to gastroesophageal reflux disease?

OBJECTIVE: Cough and laryngo-pharyngeal symptoms (LPS) are associated with gastroesophageal reflux disease (GERD). The role of acid reflux (AR) and non-acid reflux (NAR) in atypical GERD pathogenesis is controversial. The aims of the study were to determine the prevalence of high esophageal acid exposure time (AET) in patients presenting with cough or LPS and determine the incremental yield of multichannel intraluminal impedance-pH (MII-pH) monitoring. METHODS: We undertook a prospective study of patients with cough or LPS referred for GERD evaluation between January 2009 and May 2011. All patients underwent esophageal manometry, gastroscopy and MII-pH. Patients' characteristics, gastroscopy findings, distal esophageal AET, bolus exposure (BE) time and numbers of AR and NAR episodes in the proximal and distal esophagus were studied. RESULTS: Overall 50 patients (22 male, mean age 47.5 ± 14.2 years) were evaluated for unexplained chronic cough (n = 23, 46.0%), and LPS symptoms including globus (n = 10, 20.0%), sore throat (n = 12, 24.0%) and hoarse voice (n = 5, 10.0%). A normal gastroscopy, Los Angeles grade A and B esophagitis occurred in 44 (88.0%), 5 (10.0%) and 1 (2.0%) patient, respectively. Seven (14.0%) recorded elevated AET (chronic cough, 4; sore throat, 2; and hoarse voice, 1). Nine patients recorded abnormal impedance characteristics (raised BE time and/or increased reflux numbers) despite a normal AET leading to an incremental diagnostic yield of 18%. CONCLUSION: An isolated high AET is uncommon in patients with cough or LPS. Combined MII-pH improves the diagnostic yield in patients with atypical GERD manifestations.

Uvulopalatopharyngoplasty outcome assessment with quantitative computer-assisted videoendoscopic airway analysis.

CONCLUSION: Quantitative digital imaging upper airway analysis enables surgeons to assess the pre- and postoperative upper airway morphology quantitatively, objectively and accurately, and to correlate these changes in surgical parameters with improvement of obstructive sleep apnea. OBJECTIVE: This was a prospective study using a new method of quantitative computer-assisted digital-imaging videoendoscopic upper airway analysis to quantify objectively and correlate the changes in surgical parameters with improvement of obstructive sleep apnea following uvulopalatopharyngoplasty. PATIENTS AND METHODS: Nineteen male patients underwent uvulopalatopharyngoplasty for obstructive sleep apnea after continuous positive airway pressure trial. All had undergone pre- and postoperative digital imaging upper airway examination, Epworth scores, and polysomnographic studies. Postoperative static and dynamic changes in upper airway parameters were compared, analyzed and correlated with improvement of the apnea-hypopnea index (AHI) by statistical regression. RESULTS: There were 65.12% and 64.37% improvements in the AHI and Epworth scales, respectively, after uvulopalatopharyngoplasty. Retropalatal areas measured were significantly correlated with improvement of the AHI. A 1 cm2 increase in retropalatal area during Mueller's maneuver in the supine position resulted in an improvement of 32.65 in the AHI; a 1 cm increase in the transverse diameter of the retropalatal area in the erect position resulted in an improvement of 31.83 in the AHI.

Coblation vs electrocautery tonsillectomy: postoperative recovery in adults.

OBJECTIVE: Comparison of coblation and monopolar electrocautery tonsillectomy in terms of postoperative pain and recovery. STUDY DESIGN: Prospective double-blind randomized controlled trial. METHODS: Patients with recurrent tonsillitis requiring tonsillectomy were randomized to 2 groups: coblation or monopolar electrocautery tonsillectomy. Postoperative pain, complications, and days taken to return to work and normal diet were compared and analyzed with the aid of a pain diary, given to the patient. RESULTS: 67 patients were recruited. Patients undergoing coblation tonsillectomy were able to return to normal diet in a shorter space of time following surgery. Patients undergoing coblation tonsillectomy were more likely to recommend the surgery than patients undergoing electrocautery tonsillectomy. No significant differences in the daily visual analog score for pain were seen for both groups of patients. CONCLUSIONS: Our results showed that coblation tonsillectomy has a faster recovery period and may offer advantages when compared to monopolar electrocautery tonsillectomy.

Clinical predictors in obstructive sleep apnea patients with computer-assisted quantitative videoendoscopic upper airway analysis.

AIM: To identify the clinical predictors and assist surgeons in their clinical management of obstructive sleep apnea (OSA). A prospective study with a new approach to analyze the static and dynamic upper airway morphology between patients with OSA and normal subjects. METHOD: Quantitative computer-assisted videoendoscopy (validated with upper airway magnetic resonance imaging) was performed in 49 (43 males, 6 females) patients with OSA and compared with 39 (22 males, 17 females) controls (apnea-hypopnea index [AHI] < 5). Absolute cross-sectional areas and transverse and longitudinal diameters at the retropalatal and retrolingual levels were measured during end of quiet respiration and during Mueller's maneuver in the erect and supine positions, allowing us to study static and dynamic morphology (collapsibility) of the upper airway. Three thousand seven hundred forty-four (3,744) parameters were analyzed. RESULTS: In males, retropalatal and retrolingual areas during Mueller's maneuver in the supine position of 0.7981 cm (relative operating characteristics [ROC] = 0.9284, positive pressure ventilation [PPV] = 86.05%, negative pressure ventilation [NPV] = 84.62%) and 2.0648 cm (ROC = 0.8183, PPV = 76%, NPV = 83.33%), respectively, were found to be good predictors/cut-off values for OSA. The retropalatal area measured in the supine position (AS1 mol/L) and collapsibility of the retropalatal area in the supine position (CAS1) were found to have significant correlations with severity of OSA. In females, the areas measured during Mueller's maneuver in the supine position of 0.522 cm at the retropalatal level (ROC = 1, 100% PPV and NPV) and the transverse diameter at the retrolingual level during erect Mueller's maneuver of 1.1843 cm (ROC = 0.9056, PPV = 100%, NPV = 83.33%) were found to be predictive. All measurements at the retropalatal level and in the supine position had higher predictability. Area measurements obtained during Muller's maneuver were more predictive (ROC > 0.9910) than resting measurements (ROC >0.8371). Several sex and anatomic-site specific formulas with excellent predictability (ROC close or equal to 1) were also devised. CONCLUSION: Upper airway Mueller's studies are predictive and useful (independent samples t test/Mann-Whitney U test, ROC) in identifying patients with OSA. With these sex and anatomic-site specific OSA predictors/formulas and this innovative clinical method, we hope to assist other surgeons with quantitative clinical diagnosis, assessment, surgical planning, and outcome assessment tools for OSA patients.

Self-extrusion of a foreign body from the upper digestive tract to the skin.

Migrated ingested foreign bodies from the upper digestive tract have the potential to cause life-threatening complications. Cases of spontaneous expulsion to the skin of the neck are very rare. We present an unusual case of an ingested foreign body that migrated out of the upper digestive tract and self-extruded via the skin of the neck. An approach to the safe management of such seemingly innocuous foreign bodies is discussed. This report highlights the message that non-found ingested foreign bodies should be treated seriously due to the possibility of migration and resulting complications.