Perioperative complications in obstructive sleep apnea patients

BACKGROUND

Perioperative complications in obstructive sleep apnea (OSA) patients are described in a small series of case reports. No study to date systematically evaluates perioperative complications in a large number of OSA patients receiving surgeries other than those involving the pharynx.

METHODS

Names of the 860 OSA patients seen in a hospital-based sleep disorders center was cross-referenced with a list of the names of the 2,350 patients receiving surgeries in hospital during an 18 month period. In-patient and sleep center records of the 57 OSA patients receiving surgery were reviewed.

RESULTS

Nine perioperative complications occurred in eight of 48 OSA patients (17%) receiving general anesthesia. All of these complications were related to difficulties with airway management both pre- and postoperatively. Clinical characteristics including body mass index and Polysomnographie measurements of OSA severity did not prove to be useful predictors of perioperative complications.

CONCLUSIONS

The incidence of respiratory complications related to difficulties in airway management in OSA patients was higher than that reported in a recent study for all patients receiving general anesthesia (4%). The perioperative complications observed in these OSA patients are consistent with the underlying pathogenesis of OSA, pharyngeal obstruction. The absence of observed perioperative arrhythmias and myocardial ischemia is consistent with previous findings that sleep-related cardiac ischemia is uncommon in OSA patients. Our results suggest it is prudent to cautiously manage all OSA patients receiving surgeries involving general anesthesia.

Successful treatment of upper airway resistance syndrome with an oral appliance

This case report is the first description of the treatment response to an oral appliance (OA) in a patient with upper airway resistance syndrome (UARS). OAs are devices inserted into the mouth in order to modify the position of the mandible and tongue, thus relieving pharyngeal obstruction during sleep in obstructive sleep apnea (OSA) patients. Findings from this case report suggest that an OA may be a useful treatment option for UARS patients.

Telemedicine in the sleep laboratory: feasibility and economic advantages of polysomnograms transferred online

The costs for polysomnography (PSG) and alternative diagnostic procedures for sleep-disordered breathing are challenging public health care systems. We wanted to determine if a telemedicine protocol with online transfer of PSGs from a remote site could be cost-effective and clinically useful while improving patient access to full PSG. Fifty-nine PSGs were performed in 54 pulmonary patients with suspected sleep-disordered breathing at a remote hospital. The data were transferred by File Transfer Protocol (FTP) via the Internet to Walter Reed Army Medical Center (WRAMC) for scoring and interpretation. The results were faxed back to the remote hospital. Clinical utility was assessed by evaluating the reasons for patient referral and the resulting diagnoses. The economic benefits were calculated by comparing direct expenses of the telemedicine protocol with costs for contracting PSGs at outside sleep laboratories. A total of 93% (55) of all PSGs were transferred successfully online. Of the 54 patients, 47 had PSGs performed for diagnosis (including three split-night studies), 8 underwent treatment titration, and 1 patient had both overnight studies. Diagnoses were obstructive sleep apnea in 43 patients, central sleep apnea in 2, and upper airway resistance syndrome in 2. The disease conditions were defined as severe in 27 patients, moderate in 12 patients, and mild in 8 patients. Each PSG cost $700 (including costs for lost transmissions) compared to $1,250 for referral to a private sleep laboratory. A savings of $550 per study was realized with the telemedicine protocol. The online transfer of PSGs from a remote site to a centralized sleep laboratory is technically feasible and clinically useful. Telemedicine offers an effective alternative for cost reduction in sleep medicine while improving patient access to specialized care in remote areas.

Technologic advances in the treatment of obstructive sleep apnea syndrome

Among adult patients with obstructive sleep apnea syndrome (OSAS), adherence to continuous positive airway pressure (CPAP) treatment is approximately 40%, according to recent well-designed studies that evaluated outcomes other than adherence as a primary end point. This finding suggests the need for the improvement of the adult OSAS treatment approach, either by improving adherence to CPAP treatment or by developing effective alternatives to CPAP. Technologic advances have allowed for the development of new treatments for OSAS that include automatic CPAP and innovative airway procedures. Studies evaluating the application of these new technologies are reviewed. These technologic advances can be viewed as possible improvements over the existing treatment approach only if the risks and benefits of each new treatment are well understood by OSAS patients and their physicians.

Idiopathic hypersomnia in an aircrew member

In aviation, it is essential that all aircrew members remain alert and contribute, by their observations and actions, to flight safety. Especially in helicopter operations, crewmembers riding in the rear of the aircraft play an integral role in many aspects of flight, such as take-offs, landings, turns, formation flights, hazard avoidance, situational awareness, military operations, and crew coordination. We present the case of a helicopter crew chief with idiopathic hypersomnia, briefly review the disorder, and give the recent U.S. military aviation experience with sleep disorders. Flight surgeons and aeromedical examiners should be active in considering and diagnosing sleep-related disorders as the aviator or crewmember may not be aware of the disease or may not volunteer the history. A directed history is important in making the diagnosis, as are reports from family and other aircrew members. Referral to a sleep specialist is required in performing objective sleep studies, establishing the diagnosis, recommending treatment, and providing a prognosis. Many sleep disorders are treatable and aeromedically waiverable.

Comparison of respiratory polysomnographic parameters in matched cohorts of upper airway resistance and obstructive sleep apnea syndrome patients

OBJECTIVE

To compare respiratory nocturnal polysomnography (NPSG) characteristics between matched cohorts of upper airway resistance syndrome (UARS) and obstructive sleep apnea syndrome (OSAS) patients.

METHODS

All patients received 13-channel NPSG, including esophageal pressure (Pes) manometry. By definition, OSAS patients had an apnea-hypopnea index (AHI, number of apneas/hypopneas per hour total sleep time) > or = 15, and UARS patients had an AHI < 5. Respiratory effort-related arousal (RERA) was defined as the absence of apnea/hypopnea with > or = 10 s duration of progressive negative Pes, culminating in an arousal or microarousal. UARS patients, by definition, had > or = 15 RERAs per hour. Fifteen consecutively diagnosed UARS patients were matched with OSAS patients on the basis of body mass index (BMI) and gender.

RESULTS

Respiratory disturbance index (sum of the AHI and RERA per hour) was the same for both cohorts: UARS, 36+/-4; OSAS, 42+/-6 (p = 0.34). There were no differences between cohorts for mean inspiratory Pes nadirs for each 30-s epoch of sleep compared for each sleep stage over an entire night. For randomly selected breaths from supine stage 2 sleep, the mean inspiratory Pes nadir was the same for the cohorts: UARS, -16.6+/-2 cm H2O; OSAS, -16.1+/-3 cm H2O (p = 0.30). Differences between cohorts for each parameter fell within respective 95% confidence intervals.

CONCLUSION

With the exception of AHI, respiratory NPSG parameters were the same for UARS and OSAS patients when BMI and gender were controlled for.

Accuracy of respiratory inductive plethysmography for the diagnosis of upper airway resistance syndrome

OBJECTIVE

To determine the sensitivity and specificity of quantitative respiratory inductive plethysmography (RIP) compared with the "gold standard," nocturnal esophageal pressure (Pes) measurement, in the diagnosis of upper airway resistance syndrome (UARS) in adults.

METHODS

Fourteen consecutive patients without obstructive sleep apnea and suspected of having UARS underwent simultaneous measurement of Pes with a catheter and standard nocturnal polysomnography along with RIP. UARS events (RERAs, respiratory effort-related arousals) were identified by observing crescendo changes in Pes with a Pes nadir < or = -12 cm H2O, followed by an arousal or microarousal. UARS was defined as > or = 10 RERAs per hour. For each patient, the ratio of peak inspiratory flow to mean inspiratory flow (PIFMF) measured by RIP was performed during quiet wakefulness and with 40 randomly selected breaths in the supine position for two conditions: stage 2 sleep, immediately prior to arousals in any sleep stage. The mean PIFMF (wake-sleep) was calculated for each condition.

RESULTS

The sensitivities and specificities, respectively, of RIP to distinguish UARS patients from non-UARS patients are from stage 2 sleep (67%, 80%), immediately prior to arousals (100%, 100%). For breaths occurring immediately prior to arousals, the mean PIFMF (wake-sleep) is > or = 0.13 for UARS patients and < 0.13 for non-UARS patients.

CONCLUSION

The PIFMF measured by RIP allows for the most accurate identification of UARS patients when breaths are selected for analysis immediately prior to arousals.

Indications for positive airway pressure treatment of adult obstructive sleep apnea patients: a consensus statement

We developed a short-length document that clearly delineates a prudent approach to and criteria for reimbursement of positive airway pressure (PAP) costs for the treatment of obstructive sleep apnea (OSA). Treatment modalities for OSA with PAP include continuous positive airway pressure, bilevel or variable PAP, and autotitrating PAP. This guidance on the appropriate criteria for PAP use in OSA is based on widely acknowledged peer-reviewed studies and widely accepted clinical practice. These criteria reflect current opinion on the appropriate clinical management of OSA in lieu of data pending from the Sleep Heart Health Study and upcoming outcome studies. This document is not intended to provide a complete review and analysis of the OSA clinical literature. The key to the success of this document is to foster consensus within and outside the clinical sleep community by providing a common sense and easily understood approach to the treatment of OSA with PAP.

The mandibular repositioning device: role in the treatment of obstructive sleep apnea

The role of oral appliances in the routine treatment of obstructive sleep apnea (OSA) is not well defined. This prospective study attempts to clarify the clinical role of a specific oral appliance, the mandibular repositioning device (MRD). This study evaluated the demographic, polysomnographic, and cephalometric radiographic findings predictive of treatment success or failure with the MRD. Twenty-nine patients were diagnosed with mild to severe OSA by nocturnal polysomnography. The majority of these patients were intolerant to nasal continuous positive airway pressure (CPAP) and all were fitted with a MRD. Twenty-three of these patients were compliant initially with MRD use and received post-treatment nocturnal polysomnogrpahy at a mean of 104 days after receiving the device. The respiratory disturbance index (RDI) decreased with MRD use (37 +/- 23 versus 18 +/- 20 events/hour, p < 0.001), and 16 of the 23 patients (69%) were considered responders (decrease in RDI > or = 50% and posttreatment RDI < or = 20). Measurements of subjective and objective daytime sleepiness, nocturnal oxygen desaturation, and snoring were all improved with MRD use. A pre-treatment RDI > 40 was present in four of the seven (67%) non-responders. Age, body mass index, and cephalometric radiographic measurements were not predictive of treatment outcome. Sixteen of 23 patients (70%) continue to use the MRD after 3.4 +/- 0.7 years. This study suggests that the MRD is useful in the long-term treatment of patients with OSA of mild to moderate severity.

Inferior sagittal osteotomy with hyoid bone suspension for obese patients with sleep apnea

BACKGROUND

An inferior sagittal osteotomy with a sliding mandibular osteotomy and hyoid bone suspension, combined with a uvulopalatopharyngoplasty, is advocated in patients with obstructive sleep apnea who fail to tolerate nasal continuous positive airway pressure. Some investigators have suggested that this surgical procedure may be less effective in obese patients.

METHODS

Preoperative and postoperative nocturnal polysomnograms and lateral cephalometric radiographs were obtained on 12 obese patients with obstructive sleep apnea who underwent these procedures.

RESULTS

The mean +/- SD respiratory disturbance index during sleep decreased 53% +/- 11% after surgical procedures were performed (49 +/- 17 vs 23 +/- 11 events per hour, P < .001). Surgical outcome did not correlate with the body mass index, and 5 (71%) of 7 of the morbidly obese patients (body mass index, > or = 33) had greater than a 50% reduction in the respiratory disturbance index after the surgical procedures were done.

CONCLUSION

An inferior sagittal osteotomy with a sliding mandibular osteotomy and hyoid bone suspension, combined with a uvulopalatopharyngoplasty, tends to improve obstructive sleep apnea in obese patients.

Self-reported snoring in pregnancy. Association with fetal outcome

OBJECTIVES

To determine the incidence of self-reported snoring in pregnant compared with nonpregnant women. To compare indicators of fetal outcome in pregnant women with self-reported frequent snoring vs those without snoring.

STUDY DESIGN

Prospective, nonrandomized screening and comparison between groups.

PATIENTS

Three hundred fifty pregnant women and 110 age-matched nonpregnant women.

METHODS

Survey evaluating self-reported snoring. For the pregnant women, infant birthweight, APGAR scores, and other indicators of fetal outcome were obtained by record review.

RESULTS

Frequent snoring was reported in 14% of the pregnant women vs 4% of the nonpregnant women (Chi2=6.2; df=1; p<0.05). The pregnant women who reported frequent snoring did not have deliveries resulting in infants with evidence of an increase in compromised outcomes.

CONCLUSIONS

Frequent snoring is reported more often in pregnant than in nonpregnant women. Snoring mothers do not appear to be at increased risk for delivering infants with fetal compromise as might be expected with the concomitant occurrence of obstructive sleep apnea.

The effect of quiet tidal breathing on lateral cephalometric measurements

PURPOSE

In the evaluation of the upper airway in patients with sleep apnea it has been suggested that cephalometric radiographs be performed at either end-inspiration or end-expiration during quiet tidal breathing. This study sought to determine if standard soft tissue cephalometric measurements vary significantly with tidal breathing.

PATIENTS AND METHODS

In this prospective, controlled study 22 adult male patients with the sleep apnea/hypopnea syndrome and 27 nonapneic, nonsnoring male controls had cephalometric radiographs performed at end-tidal inspiration and end-tidal expiration. The measurements obtained from each radiograph included the posterior airway space distance, the mandibular plane to hyoid distance, and the posterior nasal spine to tip of palate (PNS-P) distance.

RESULTS

There were no statistically significant differences between the inspiratory and expiratory measurements in either group. Only the PNS-P distance differed significantly between the two groups. Changes in cephalometric measurements did not occur uniformly in any one direction with tidal breathing.

CONCLUSION

The data indicate that coordinating radiographic exposure to respiratory cycle phase is not necessary for soft-tissue measurements commonly used to assess upper airway patency in patients with the sleep apnea/hypopnea syndrome.

Weight loss for obstructive sleep apnea: the optimal therapy for obese patients

Obstructive sleep apnea (OSA) is a common disorder in which upper-airway obstruction during sleep results in cessation of breathing. OSA is associated with increased morbidity and mortality and impaired daytime functioning. Upper-body obesity is a risk factor for OSA, and it is well documented that weight loss has a notable ameliorative impact on the occurrence of OSA. Nasal continuous positive airway pressure (nCPAP) during sleep is the primary treatment for OSA, and is usually effective in relieving upper-airway obstruction. However, compliance with prolonged nCPAP use has been proven problematic. Upper-airway surgeries may be efficacious for the treatment of OSA in carefully selected patients, but often are not successful for obese patients with OSA. The concomitant use of nCPAP and behavioral weight loss therapy in obese patients with OSA may result in enhanced weight loss. In moderately obese patients, modest weight reduction may alleviate the need for long-term nCPAP therapy or upper-airway surgery. Severely obese patients usually require more substantial weight loss and may be candidates for behavioral therapy in combination with gastric surgery. The role of the dietitian in the treatment of OSA cannot be overemphasized and warrants further development and study.

The effect of forceps size on the adequacy of specimens obtained by transbronchial biopsy

This study prospectively compared the diagnostic yield of transbronchial biopsies using large and small forceps (cup sizes, 3 x 2 x 0.9 versus 2 x 1.5 x 0.6 mm, respectively). Diagnostic yield was compared by a pathologist, blinded to the size of forceps used on the basis of the relative amount of tissue obtained, alveolar tissue obtained, and ability to ascertain a histopathologic diagnosis. Large forceps obtained significantly more tissue than did small forceps (20 of 27 patients [74%] versus five of 27 patients [19%], p < 0.005, with similar amounts obtained in two patients). Also, large forceps obtained significantly more alveolar tissue than did small forceps (16 of 22 patients [73%] versus six of 22 patients [27%], p < 0.05, with no alveolar tissue obtained in five patients). In 18 of the 27 patients, biopsies performed resulted in nonspecific diagnoses, including fibrosis or chronic inflammation. All nine of the patients with a specific diagnosis were ultimately proved to have sarcoidosis. There was a trend toward more of these patients having noncaseating granulomas obtained with the large forceps than with the small forceps (seven of nine patients versus four of nine patients). No difference was observed in the amount of postbiopsy bleeding with either forceps. We conclude that large forceps used for transbronchial biopsy yield more tissue and more alveolar tissue than do small forceps. These findings may have an impact on the diagnostic yield in some diseases such as sarcoidosis.