Mueller Maneuver Research Articles

Comparing Ways of Assessing Tongue Base Obstruction in Obstructive Sleep Apnea

Objective: To determine if awake clinical evaluation methods like Friedman’s Tongue Position (FTP), endoscopic assessment of the hypopharynx using Mueller maneuver (MM), and during end expiration (EEPBOT) to assess tongue-base obstruction correlate well with tongue-base obstruction seen during drug-induced sleep endoscopy (DISE). Method: Pilot prospective study of 16 patients with moderate to severe OSA recruited over 1 year at a tertiary care center. These patients were evaluated in the clinic with the flexible nasendoscope and subsequently underwent full PSG and DISE with midazolam. Results: The 16 patients studied had a mean AHI of 65 (range, 18.8 to 129). Fifteen out of 16 patients (93.7%) were found to have multi segment obstruction on DISE according to the original grading proposed by Pringle and Croft. Comparing the various awake dynamic maneuvers against DISE as a gold standard, MM was found to have sensitivity of 53%, FTP had a sensitivity of 80%, and EEPBOT had a sensitivity of 93%. Because of the skewed nature of the results (only 1 out of 16 patients [6.3%] was classified as not having obstruction), specificity results had no statistical value. Conclusion: This small pilot study showed a good correlation between EEPBOT, FTP, and DISE. A poorer correlation between MM and DISE is seen. Our results suggest that EEPBOT and FPP are superior to MM in evaluating tongue-base obstruction in OSA; however, further research is required to support these findings.

The effects of simulated obstructive apnea and hypopnea on arrhythmic potential in healthy subjects

Preliminary evidence supports an association between OSA and cardiac dysrhythmias. Negative intrathoracic pressure, as occurring during OSA, may provoke cardiac dysrhythmias. Thus, we aimed to study the acute effects of simulated apnea and hypopnea on arrhythmic potential and measures of cardiac repolarization [QT(C) and T (peak) to T (end) intervals [TpTec]) in humans. In 41 healthy volunteers, ECG was continuously recorded prior, during and after simulated obstructive hypopnea (inspiration through a threshold load), simulated apnea (Mueller maneuver), end-expiratory central apnea and normal breathing in randomized order. The number of subjects with premature beats was significantly higher during inspiration through a threshold load (n = 7), and the Mueller maneuver (n = 7) compared to normal breathing (n = 0) (p = 0.008 for all comparisons), but not during end-expiratory central apnea (n = 3, p = 0.125). Inspiration through a threshold load was associated with a non-significant mean (SD) increase of the QT(C) interval [+5.4 (22.4) ms, 95 %CI -1.7 to +12.4 ms, p = 0.168] and a significant increase of the TpTcc interval [+3.7 (8.9) ms, 95 %CI +0.9 to +6.6 ms, p = 0.010]. The Mueller maneuver induced a significant increase of the QT(C) interval [+8.3 (23.4) ms, 95 %CI 0.9 to +15.6 ms, p = 0.035] and the TpTec interval (+4.2 (8.2) ms, 95 %CI +1.6 to +6.8 ms, p = 0.002). There were no significant changes of the QT(C) and TpTec intervals during central end-expiratory apnea. These data indicate that simulated obstructive apnea and hypopnea are associated with an increase of premature beats and prolongation of QT(C) and TpTec intervals. Therefore, negative intrathoracic pressure changes may be a contributory mechanism for the association between OSA and cardiac dysrhythmias.

Changes of ophthalmic blood flow in obstructive sleep apnea-hypopnea syndrome

To observe the ophthalmic artery (OA), central retinal artery (CRA) and posterior ciliary artery (PCA) blood flow and the changes of eye vascular auto-regulation in patients with obstructive sleep apnea-hypopnea syndrome (OSAS). It was a case-control study. Fifteen health overweight male adult (as normal control) and 42 patients with OSAS were randomly selected from examination center and sleep detection center, respectively. The OSAS patients were divided into mild (14 patients) and moderate and severe (28 patients) groups based on the apnea-hypopnea index (AHI). All subjects filled the sleep questionnaire and carried out polysomnogram monitoring all night for at least 7 hours. Fasting peripheral venous blood was collected at 7 AM on next day. The end-tidal CO(2) (ETCO(2)), intraocular pressure and color doppler sonography were examined next day to record the data in the inspection process before and after Mueller maneuver. Doppler ultrasound measurement of ocular blood flow diameter and blood flow velocity values were described in the median (max, min) and compared with Kruskal-Wallis test. And then two groups were compared with Bonferroni t test. Ocular blood flow velocity of patients with OSAS and PSG monitoring indicators were analyzed using partial correlation analysis. OA inner diameter in moderate and severe OSAS group [0.08 (0.15, 0.06) cm] was lower than that in healthy control [0.15 (0.26, 0.11) cm] and the difference was statistically significant (P = 0.000). PCA inner diameter in moderate and severe OSAS group [0.10 (0.13, 0.07) cm] were higher than that in healthy controls [0.05 (0.09, 0.04) cm]. CRA peak systolic velocity (PSV) in moderate and severe OSAS group [16.50 (19.40, 13.10) cm/s] was greater than that in healthy controls [11.30 (16.70, 8.20) cm/s]. The differences between these two groups were statistically significant (PCA inner diameter: P = 0.000, CRA-PSV: P = 0.001). The difference of CRA end diastolic velocity (EDV) between the moderate and severe group [8.90 (9.90, 5.10) cm/s], mild group [7.00 (8.30, 4.50) cm/s] and healthy control group [5.50 (7.40, 3.40) cm/s] was statistically significant (χ(2) = 14.45, P < 0.05). PCA-PSV [32.50 (43.10, 19.10) cm/s] and PCA-EDV [12.80 (15.20, 5.70) cm/s] in the moderate and severe group were higher than those in healthy control group [22.60 (32.20, 12.40) cm/s] and [7.20 (11.20, 3.90) cm/s], as well as those in the mild group [24.00 (30.70, 13.30) cm/s] and [8.00 (9.90, 3.90) cm/s]. These differences were statistically significant (PCA-PSV: P = 0.000, 0.002; PCA-EDV: P = 0.000, 0.001). The diameter of OA and PCA correlated negatively with ETCO(2) (r = -0.41, -0.34; P < 0.05); CRA-PSV was correlated with SaO2 min (r = -0.37, P < 0.05). CRA-EDV was correlated with ETCO(2) and SaO2 mean (r = 0.57, -0.39; P < 0.05). PCA-PSV was correlated with SaO2 min and MAI (r = -0.34, 0.56; P < 0.05). PCA-EDV was correlated SaO2 min and MAI (r = -0.29, 0.61; P < 0.05). The diameter and blood flow of OA, PCA and CRA change in OSAS patients. Compared with non-OSAS patients, the autoregulation function of PCA and CRA is weakened in OSAS patients.

Response patterns of arterial pressure and heart period to Mueller manoeuvre and their comparison to those of Valsalva manoeuvre

It has not been established if the Mueller manoeuvre (MM) induces characteristic arterial pressure (AP) and heart rate changes analogous to those observed during its respiratory strain opposite, the Valsalva manoeuvre (VM). Our aims were to explore, on a beat-by-beat basis, if MM evokes well-defined changes in AP and heart period (HP), and to compare these responses with those of VM. From the ECG and AP records of 24 healthy subjects who performed VM and MM in sitting position, RR intervals and AP series were computed. The series were ensemble-averaged, and the characteristic points that limit the phases were semi-automatically detected from each record. Our main findings were: (i) MM provoked consistent patterned responses in both AP and HP in the same four phases of VM; (ii) the AP and HP changes of MM were parallel to those of VM in phases II and IV, and opposite in direction in phases I and III; (iii) pooled data during the strain and poststrain and the mean characteristic points of AP and HP were smaller in MM than in VM (P< 0.001); (iv) MM presented two changes absent in VM, AP and HP rise immediately after phase I and hypotension in late phase IV; (v) systolic pressure and HP presented a strong positive correlation (r=0.87 ± 0.02) in late phase II of MM. Our study characterizes on a phase-by-phase basis the AP and RR interval responses to MM, documents their great similarity to those corresponding to VM and establishes that MM exerts a 50% smaller impact on the cardiovascular autonomic function than VM.

A Case of Paradoxical Embolic ST-Segment Elevation Myocardial Infarction Triggered by Sleep Apnea

This report describes an obese 39-year-old man who experienced ST-segment elevation myocardial infarction with total thrombotic occlusion of the right coronary artery. Culprit vessel flow was improved by aspiration. Data suggested that myocardial infarction had resulted from paradoxical embolus via a patent foramen ovale triggered by the Mueller maneuver, which had induced negative intrathoracic pressure following an acute increase of right-heart volume in the context of obesity and sleep-disordered breathing (SDB). Obesity is increasing among younger populations and it represents a risk for SDB and thrombosis. Thus, this mechanism should be included within the differential diagnosis for myocardial infarction in young patients.

Cardiac and vascular responses to thigh cuffs and respiratory maneuvers on crewmembers of the International Space Station

The transition to microgravity eliminates the hydrostatic gradients in the vascular system. The resulting fluid redistribution commonly manifests as facial edema, engorgement of the external neck veins, nasal congestion, and headache. This experiment examined the responses to modified Valsalva and Mueller maneuvers measured by cardiac and vascular ultrasound (ECHO) in a baseline steady state and under the influence of thigh occlusion cuffs available as a countermeasure device (Braslet cuffs). Nine International Space Station crewmember subjects (expeditions 16-20) were examined in 15 experiment sessions 101 ± 46 days after launch (mean ± SD; 33-185). Twenty-seven cardiac and vascular parameters were obtained with/without respiratory maneuvers before and after tightening of the Braslet cuffs (162 parameter states/session). Quality of cardiac and vascular ultrasound examinations was assured through remote monitoring and guidance by investigators from the NASA Telescience Center in Houston, TX, and the Mission Control Center in Korolyov, Moscow region, Russia. 14 of 81 conditions (27 parameters measured at baseline, Valsalva, and Mueller maneuver) were significantly different when the Braslet was applied. Seven of 27 parameters were found to respond differently to respiratory maneuvers depending on the presence or absence of thigh compression. Acute application of Braslet occlusion cuffs causes lower extremity fluid sequestration and exerts commensurate measurable effects on cardiac performance in microgravity. Ultrasound techniques to measure the hemodynamic effects of thigh cuffs in combination with respiratory maneuvers may serve as an effective tool in determining the volume status of a cardiac or hemodynamically compromised patient at the "microgravity bedside."

Peculiarities of clinical profile of snoring and mild to moderate obstructive sleep apnea–hypopnea syndrome patients

The purpose of this study is to perform comprehensive evaluation of the snoring and mild to moderate obstructive sleep apnea-hypopnea syndrome (OSAHS) patients for their anatomical, functional, and psychoemotional clinical properties. Seventy-four snoring patients, aged 24 to 64 (mean 41.83 ± 11.01) years underwent full-night polysomnography, nasopharyngoscopy, and Mueller maneuver. Clinical tests battery consisting of visual analogue scales (VAS) scales, Lithuanian version of Sleep Apnea Quality of Life Index (SAQLI-LT), Spielberg's State-Trait Anxiety Inventory (STAI), Beck Depression Inventory-Second Edition (BDI-II), and Epworth Sleepiness Scale (ESS) were applied to assess their distinctive clinical properties. The total group of snoring and mild to moderate OSAHS patients presented with considerably enlarged VAS snoring and daytime sleepiness scores (mean 66.32 ± 19.07 and 35.03 ± 27.83 points), mild BDI-II scores (mean 10.96 ± 9.42 points), and moderate trait anxiety scores (mean 41.51 ± 8.62 points). All the scores of daytime complaints measured with the VAS correlated statistically significantly with the mean scores of the ESS, SAQLI-LT, trait anxiety, and BDI-II. Both groups, of snoring and mild to moderate OSAHS patients, indicated similar intensity of the major complaints according to the VAS, same as similar BDI-II, STAI, and SAQLI-LT scores. A higher Friedman's score of palatal tonsils was found in the group of snoring patients, comparing to that of the group of mild to moderate OSAHS patients (p < 0.05). Snoring and mild to moderate OSAHS patients have resemblances in their distinctive anatomical and clinical properties. This group of the patients revealed mild depression and moderate trait anxiety scores when measured with the BDI-II and STAI, which correlated significantly with the severity of the patients' daytime complaints measured with the VAS.

A videoendoscopic evaluation of the upper airway in South East Asian adults with obstructive sleep apnea

We aimed to evaluate the severity of upper airway obstruction at the retropalatal and retroglossal regions in obstructive sleep apnea (OSA) patients. This is a descriptive cross-sectional study at the Sleep Clinic, Department of Otorhinolaryngology-Head and Neck Surgery. Flexible nasopharyngolaryngoscopy was performed in seated erect and supine position. Retropalatal and retroglossal regions were continuously recorded during quiet breathing and Mueller's maneuver in both positions. Captured images were measured using Scion Image software and narrowing rate was calculated. Level of each site was classified based on Fujita classification and severity of obstruction using Sher scoring system for Mueller's maneuver. A total of 59 patients participated in this study. Twenty-nine (49.2%) participants had type 1 (retropalatal) obstruction, 23 (38.9%) had type 2 (retropalatal and retroglossal), and seven (11.9%) in type 3 (retroglossal) obstruction. Fifty (84.7%) of the patients have severe obstruction at the retropalatal region in supine position (SRP) followed by 35 (59.3%) at retropalatal region in erect position (ERP), 27 (45.8%) at retroglossal region in supine position (SRG) and eight (13.5%) at retroglossal region in erect position (ERG). The average oxygen saturation showed significant association in ERP (P = 0.012) and SRP (P < 0.001), but not significant in ERG and SRG. Videoendoscopy utilizing flexible nasopharyngolaryngoscopy and Scion Image software is reliable, minimally invasive, and useful as an office procedure in evaluating the multilevel obstruction of upper airway in OSA patients. The retropalatal region has more severe obstruction compared with retroglossal region either in erect or supine position.

Case Scenario: Acute Postoperative Negative Pressure Pulmonary Edema

A 25-yr-old man (weight, 68 kg; height, 183 cm) presentedto the surgery center for excision of back and thigh schwan-nomas on the same day. The patient’s medical history wassignificant only for his history of multiple schwannoma re-sections and a history of smoking one pack of cigarettes perweek for the past 5 yr. He denied previous problems withgeneral anesthesia, and his baseline peripheral oxygen satu-ration was 99% on ambient air.Thepatientwaspremedicatedwith2mgmidazolam,andanesthesia was induced with 250 mg fentanyl, 500 mg thio-pental, and 8 mg vecuronium given for facilitation of tra-cheal intubation. He was atraumatically intubated with a7-mm ID endotracheal tube using a no. 3 Macintosh laryn-goscope (Teleflex Medical, Research Triangle Park, NC) onthe first attempt with direct visualization of the vocal cords.The patient was turned prone, bilateral breath sounds werereconfirmed, and schwannoma excisions were performed ontheleftthighandtheleftflank.Atotalof0.5mghydromor-phone was administered for analgesia. The intraoperativecoursewasunremarkable.Thepatientwashemodynamicallystable with minimal blood loss and was easily ventilated andoxygenated. A total of 500 ml lactated Ringer’s solution wasadministeredduringthe65-minsurgicalprocedure.Thepa-

An integrative model of respiratory and cardiovascular control in sleep-disordered breathing

While many physiological control models exist in the literature, none thus far has focused on characterizing the interactions among the respiratory, cardiovascular and sleep-wake regulation systems that occur in sleep-disordered breathing. The model introduced in this study integrates the autonomic control of the cardiovascular system, chemoreflex and state-related control of respiration, including respiratory and upper airway mechanics, along with a model of circadian and sleep-wake regulation. The integrative model provides realistic predictions of the physiological responses under a variety of conditions including: the sleep-wake cycle, hypoxia-induced periodic breathing, Cheyne-Stokes respiration in chronic heart failure, and obstructive sleep apnoea (OSA). It can be used to investigate the effects of a variety of interventions, such as isocapnic and hypercapnic and/or hypoxic gas administration, the Valsalva and Mueller maneuvers, and the application of continuous positive airway pressure on OSA subjects. By being able to delineate the influences of the various interacting physiological mechanisms, the model is useful in providing a more lucid understanding of the complex dynamics that characterize state-cardiorespiratory control in the different forms of sleep-disordered breathing.

Changes in Left and Right Ventricular Mechanics During the Mueller Maneuver in Healthy Adults

Background— Obstructive sleep apnea is highly prevalent in patients with cardiovascular disease and has detrimental effects on systolic and diastolic function of the ventricles. In this research, the changes in strain (S) and strain rate (SR) during the performance of the Mueller maneuver (MM) in an effort to better understand how negative intrathoracic pressures affect ventricular mechanics. Methods and Results— The MM was performed to maintain a target intrathoracic pressure of −40 mm Hg. Echocardiography was used to measure various parameters of cardiac structure and function. Myocardial deformation measurements were performed using tissue speckle tracking. Twenty-four healthy subjects (9 women; mean age, 30�6 years) were studied. Global left ventricular longitudinal S in systole and SR in early filling were significantly decreased during the MM (S: baseline, −17.0�1.6%; MM, −14.5�2.2%; P &lt;0.0001, SR: baseline, 1.09�0.20 s −1 ; MM, 0.92�0.21 s −1 ; P =0.01). Global right ventricular longitudinal S was also significantly decreased during the MM (baseline, −22.0�3.1%; MM, −17.2�2.5%; P &lt;0.0001), as was global right ventricular longitudinal systolic SR (baseline, −1.34�0.35 s −1 ; MM, −1.02�0.21 s −1 ; P =0.0006). Conclusions— Left ventricular and right ventricular longitudinal deformation are significantly reduced during the MM. These results suggest that negative intrathoracic pressure during apnea may contribute to changes in myocardial mechanics. These results could help explain the observed changes in left ventricular and right ventricular mechanics in patients with obstructive sleep apnea.

Right ventricular tissue Doppler assessment in space during circulating volume modification using the Braslet device

Introduction: This joint US–Russian work aims to establish a methodology for assessing cardiac function in microgravity in association with manipulation of central circulating volume. Russian Braslet-M (Braslet) occlusion cuffs were used to temporarily increase the volume of blood in the lower extremities, effectively reducing the volume in central circulation. The methodology was tested at the International Space Station (ISS) to assess the volume status of crewmembers by evaluating the responses to application and release of the cuffs, as well as to modified Valsalva and Mueller maneuvers. This case study examines the use of tissue Doppler (TD) of the right ventricular (RV) free wall. Results: Baseline TD of the RV free wall without Braslet showed early diastolic E′ (16 cm/s), late diastolic A′ (14 cm/s), and systolic S′ (12 cm/s) velocities comparable with those in normal subjects on Earth. Braslet application caused 50% decrease of E′ (8 cm/s), 45% increase of A′, and no change to S′. Approximately 8 beats after the Braslet release, TD showed E′ of 8 cm/s, A′ of 12 cm/s, and S′ of 13 cm/s. At this point after release, E′ did not recover to baseline values while l A′ and S′ did recover. The pre-systolic cross-sectional area of the internal jugular vein without Braslet was 1.07 cm 2, and 1.13 cm 2 10 min after the Braslet was applied. The respective cross-sectional areas of the femoral vein were 0.50 and 0.54 cm 2. The RV myocardial performance Tei index was calculated by dividing the sum of the isovolumic contraction time and isovolumic relaxation time by the ejection time ((IVCT+IVRT)/ET); baseline and Braslet-on values for Tei index were 0.25 and 0.22, respectively. Braslet Tei indices are within normal ranges found in healthy terrestrial subjects and temporarily become greater than 0.4 during the dynamic Braslet release portion of the study. Conclusions: TD modality was successfully implemented in space flight for the first time. TD of RV revealed that the Braslet influenced cardiac preload and that fluid was sequestered in the lower extremity interstitial and vascular space after only 10 min of application. This report demonstrates that Braslet application has an effect on RV physiology in long-duration space flight based on TD, and that this effect is in part due to venous hemodynamics.

Update: Diagnostik der oberen Atemwege bei Schlafapnoe-Syndrom

During the past two decades, different methods of upper airway evaluation for patients with obstructive sleep apnea (OSA) have been investigated. Although clinical assessment is the basis of any diagnostic workflow in OSA, the Mueller maneuver is apparently of no importance. Imaging techniques have increased our knowledge of the pathophysiology of OSA. Cephalometry is done only if maxillomandibular advancement is planned; dynamic investigations such as computed tomography and magnetic resonance imaging are able to picture the pharyngeal collapse and have the capacity to simulate the effect of interventions on OSA severity. So far, video endoscopy under sedation can only predict the success of oral appliances. Multichannel pressure recordings depict the distribution of obstructive events in the upper or lower pharyngeal segment during the entire night. The impact of sophisticated upper airway evaluation remains limited compared with standard clinical assessment. Further research is needed to develop valuable tools for the diagnostic workup of patients with OSA.

Dynamic Changes of Left Ventricular Performance and Left Atrial Volume Induced by the Mueller Maneuver in Healthy Young Adults and Implications for Obstructive Sleep Apnea, Atrial Fibrillation, and Heart Failure

Using the Mueller maneuver (MM) to simulate obstructive sleep apnea (OSA), our aim was to investigate acute changes in left-sided cardiac morphologic characteristics and function which might develop with apneas occurring during sleep. Strong evidence supports a relation between OSA and both atrial fibrillation and heart failure. However, acute effects of airway obstruction on cardiac structure and function have not been well defined. In addition, it is unclear how OSA might contribute to the development of atrial fibrillation and heart failure. Echocardiography was used in healthy young adults to measure various parameters of cardiac structure and function. Subjects were studied at baseline, during, and immediately after performance of the MM and after a 10-minute recovery. Continuous heart rate, blood pressure, and pulse oximetry measurements were made. During the MM, left atrial (LA) volume index markedly decreased. Left ventricular (LV) end-systolic dimension increased in association with a decrease in LV ejection fraction. On release of the maneuver, there was a compensatory increase in blood flow to the left side of the heart, with stroke volume, ejection fraction, and cardiac output exceeding baseline. After 10 minutes of recovery, all parameters returned to baseline. In conclusion, sudden imposition of severe negative intrathoracic pressure led to an abrupt decrease in LA volume and a decrease in LV systolic performance. These changes reflected an increase in LV afterload. Repeated swings in afterload burden and chamber volumes may have implications for the future development of atrial fibrillation and heart failure.

Airway evaluation in obstructive sleep apnea

As the interest in sleep-disordered breathing has increased, various attempts have been made to assess upper airway anatomy in patients with this relatively frequent disorder. The aim is not only to reveal potential differences in upper airway anatomy to better understand origin and pathophysiology of the disease but also to improve patient management and treatment success. The present review is based on a systematic literature search with regard to upper airway evaluation in sleep-disordered breathing; the articles were selected and discussed in light of our clinical experiences. Based on clinical assessment including endoscopy during wakefulness, the value of the Mueller Maneuver, static radiologic imaging techniques (X-ray cephalometry, computed tomography (CT) scanning and magnetic resonance imaging (MRI)), dynamic scanning protocols (e.g. ultrafast CT or cine MRI), upper airway endoscopy during sleep and sedated sleep, pressure measurements and the assessment of the critical closing pressure are discussed. Each technique itself and its history in the field of sleep medicine are briefly reviewed and problems of standardization and interpretation are discussed when appropriate. Insights into the pathophysiology of the disease gained with the help of the investigational techniques are presented and the impact of the techniques on patient management is reported. Although all these additional techniques for upper airway assessment have substantially improved our understanding of sleep-disordered breathing, their significance in daily practice is limited. In contrast to the widespread use of the Mueller maneuver and sedated endoscopy, convincing data supporting their use in terms of treatment outcome are lacking. So far, there is only very limited evidence that selected techniques improve treatment outcome for selected indications. In general, there is not enough evidence that these techniques are superior to the routine clinical assessment.

Sensitivity for Detection of Patent Foramen Ovale Increased with Increasing Number of Contrast Injections: A Descriptive Study with Contrast Transesophageal Echocardiography

We sought to study the diagnostic yield of increasing numbers of contrast injections for detection of patent foramen ovale (PFO) during transesophageal echocardiography. Contrast was injected twice during each of 10 provocations to 30 patients screened for PFO. Injections were given during quiet respiration, early Valsalva (starting 3-5 seconds before injection), late Valsalva (starting 3-5 seconds after injection), Mueller maneuver, coughing, bed tilt during early Valsalva, after nitroglycerin spray during both quiet respiration, and early Valsalva. The number of detected PFOs increased as the number of injections increased (r = 0.79, P < .01). Five injections per patient detected all 11 large PFOs. To eventually detect all 14 PFOs among the 30 study patients required a total of 11 injections per patient. The sensitivity for PFO detection increased when additional contrast injections were given. At least 5 injections are required to safely detect or rule out the presence of a PFO.

Variations in pulmonary artery occlusion pressure to estimate changes in pleural pressure

A readily available assessment of changes in pleural pressure would be useful for ventilator and fluid management in critically ill patients. We examined whether changes in pulmonary artery occlusion pressure (Ppao) adequately reflect respiratory changes in pleural pressure as assessed by changes in intraesophageal balloon pressure (Peso). We studied patients who had a pulmonary catheter and esophageal balloon surrounding a nasogastric tube as part of their care (n=24). We compared changes in Ppao (dPpao) to changes in Peso (dPeso) by Bland-Altman and regression analysis. Adequacy of balloon placement was assessed by performing Mueller maneuvers and adjusting the position to achieve a ratio of dPeso to change in tracheal pressure (dPtr) of 0.85 or higher. This was achieved in only 14 of the 24 subjects. We also compared dCVP to dPeso. The dPpao during spontaneous breaths and positive pressure breaths gave a good estimate of Peso but generally underestimated dPeso (bias=2.2 +8.2 and -3.9 cmH2O for the whole group). The dCVP was not as good a predictor (bias=2.9 +10.3 and -4.6). In patients who have a pulmonary artery catheter in place dPpao gives a lower estimate of changes in pleural pressure and may be more reliable than dPeso. The dCVP is a less reliable predictor than changes in pleural pressure.

Z-Palatoplasty

Z-Palatoplasty

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.

The Prognostic Value of Simulated Snoring in Awake Patients With Suspected Sleep-Disordered Breathing: Introduction of a New Technique of Examination

A clinical examination of the upper airway in patients with suspected sleep-disordered breathing (SDB) is frequently performed before nighttime polysomnography. In recent years, the findings of "static" examinations, such as dorsalization of the tongue base, the Malampatti index, and Mueller maneuver, have been determined to be of low predictive value. We developed a new method of "dynamic" examination of the upper airway during simulated snoring in awake patients and analyzed the method in terms of the predictive value for suspected SDB. N/A PATIENTS: One hundred thirty-one patients were examined prior to night-time polysomnography, and the results were correlated with the apneahypopnea-index (AHI). N/A RESULTS: A significant correlation was detected between an increased dorsal movement of the tongue base, as well as with pharyngeal collapse at the level of the tongue base and the AHI. Pharyngeal collapse at the level of the velum did not correlate with the AHI. The patient's body position during simulated snoring did not influence the results. The "static" examinations, such as the dorsalization of the tongue base, tonsil size, Malampatti index, and Mueller maneuver, did not correlate with the AHI. Patients with a high degree of pharyngeal collapse at the level of the tongue base, in combination with dorsal movement of the tongue base during simulated snoring, revealed a probability of 75% to have an AHI more than 10 and of 92% for an AHI more than 5. The "dynamic" examination of the upper airway under simulated snoring in awake patients is an easy-to-perform method to predict the probability of SDB prior to nighttime polysomnography.