Sleep Apnea Syndromes: Parthasarathy S

Kushida CA, Chediak A, Berry RB, Brown LK, Gozal D, Iber C, Parthasarathy S, Quan SF, Rowley JA, Anonymous00026, Anonymous00027. · Stanford University Center of Excellence for Sleep Disorders, 401 Quarry Road, Suite 3301, Stanford, CA 94305-5730, USA. · J Clin Sleep Med. · Pubmed #18468315 links to  free full text

Abstract: Positive airway pressure (PAP) devices are used to treat patients with sleep related breathing disorders (SRBDs), including obstructive sleep apnea (OSA). After a patient is diagnosed with OSA, the current standard of practice involves performing attended polysomnography (PSG), during which positive airway pressure is adjusted throughout the recording period to determine the optimal pressure for maintaining upper airway patency. Continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BPAP) represent the two forms of PAP that are manually titrated during PSG to determine the single fixed pressure of CPAP or the fixed inspiratory and expiratory positive airway pressures (IPAP and EPAP, respectively) of BPAP for subsequent nightly usage. A PAP Titration Task Force of the American Academy of Sleep Medicine reviewed the available literature. Based on this review, the Task Force developed these recommendations for conducting CPAP and BPAP titrations. Major recommendations are as follows: (1) All potential PAP titration candidates should receive adequate PAP education, hands-on demonstration, careful mask fitting, and acclimatization prior to titration. (2) CPAP (IPAP and/or EPAP for patients on BPAP) should be increased until the following obstructive respiratory events are eliminated (no specific order) or the recommended maximum CPAP (IPAP for patients on BPAP) is reached: apneas, hypopneas, respiratory effort-related arousals (RERAs), and snoring. (3) The recommended minimum starting CPAP should be 4 cm H2O for pediatric and adult patients, and the recommended minimum starting IPAP and EPAP should be 8 cm H2O and 4 cm H2O, respectively, for pediatric and adult patients on BPAP. (4) The recommended maximum CPAP should be 15 cm H2O (or recommended maximum IPAP of 20 cm H2O if on BPAP) for patients < 12 years, and 20 cm H2O (or recommended maximum IPAP of 30 cm H2O if on BPAP) for patients > or = 12 years. (5) The recommended minimum IPAP-EPAP differential is 4 cm H2O and the recommended maximum IPAP-EPAP differential is 10 cm H2O (6) CPAP (IPAP and/or EPAP for patients on BPAP depending on the type of event) should be increased by at least 1 cm H2O with an interval no shorter than 5 min, with the goal of eliminating obstructive respiratory events. (7) CPAP (IPAP and EPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least 1 obstructive apnea is observed for patients < 12 years, or if at least 2 obstructive apneas are observed for patients > or = 12 years. (8) CPAP (IPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least 1 hypopnea is observed for patients < 12 years, or if at least 3 hypopneas are observed for patients > or = 12 years. (9) CPAP (IPAP for patients on BPAP) should be increased from any CPAP (or IPAP) level if at least 3 RERAs are observed for patients < 12 years, or if at least 5 RERAs are observed for patients > or = 12 years. (10) CPAP (IPAP for patients on BPAP) may be increased from any CPAP (or IPAP) level if at least 1 min of loud or unambiguous snoring is observed for patients < 12 years, or if at least 3 min of loud or unambiguous snoring are observed for patients > or = 12 years. (11) The titration algorithm for split-night CPAP or BPAP titration studies should be identical to that of full-night CPAP or BPAP titration studies, respectively. (12) If the patient is uncomfortable or intolerant of high pressures on CPAP, the patient may be tried on BPAP. If there are continued obstructive respiratory events at 15 cm H2O of CPAP during the titration study, the patient may be switched to BPAP. (13) The pressure of CPAP or BPAP selected for patient use following the titration study should reflect control of the patient's obstructive respiration by a low (preferably < 5 per hour) respiratory disturbance index (RDI) at the selected pressure, a minimum sea level SpO2 above 90% at the pressure, and with a leak within acceptable parameters at the pressure.) (14) An optimal titration reduces RDI < 5 for at least a 15-min duration and should include supine REM sleep at the selected pressure that is not continually interrupted by spontaneous arousals or awakenings. (15) A good titration reduces RDI < or = 10 or by 50% if the baseline RDI < 15 and should include supine REM sleep that is not continually interrupted by spontaneous arousals or awakenings at the selected pressure. (16) An adequate titration does not reduce the RDI < or = 10 but reduces the RDI by 75% from baseline (especially in severe OSA patients), or one in which the titration grading criteria for optimal or good are met with the exception that supine REM sleep did not occur at the selected pressure. (17) An unacceptable titration is one that does not meet any one of the above grades. (18) A repeat PAP titration study should be considered if the initial titration does not achieve a grade of optimal or good and, if it is a split-night PSG study, it fails to meet AASM criteria (i.e., titration duration should be > 3 hr).

Budhiraja R, Parthasarathy S, Quan SF. · Division of Pulmonary and Critical Care, Department of Medicine, Southern Arizona Veterans Affairs Health Care System, Tucson, AZ 85723, USA. · J Clin Sleep Med. · Pubmed #17694731 links to  free full text

Abstract: Obstructive sleep apnea (OSA) is a common disorder and is associated with adverse cardiovascular consequences, including hypertension and coronary artery disease. While the mechanisms responsible for increased risk of cardiovascular events in OSA have not yet been fully elucidated, hypoxia, inflammation, obesity, metabolic dysregulation, and sympathetic activation, may contribute to these consequences. Endothelial dysfunction may be another link between OSA and cardiovascular disease. Dysfunctional endothelium is characterized by an imbalance in production of vasoactive hormones, increased adherence of inflammatory mediators to endothelial cells and hypercoagulability, and is a known risk factor for cardiovascular events. Studies have directly measured vascular endothelial function in patients with OSA and found a muted response compared to controls. Other studies have evaluated biochemical markers of endothelial function including circulating levels of vasoactive and thrombosis mediators and provide further proof of endothelial dysfunction in this disorder. A better appreciation of the role of the dysfunctional endothelium in OSA will help shed light on the pathogenesis of cardiovascular disease in this disorder and may lead to development of novel therapies aimed at preventing untoward outcomes.

Cabello B, Parthasarathy S, Mancebo J. · Intensive Medicine Service, Santa Creu i Sant Pau Hospital, Barcelona, Spain. · Curr Opin Crit Care. · Pubmed #17198045 No free full text.

Abstract: PURPOSE OF REVIEW: This review provides a background in mechanical ventilation and sleep. RECENT FINDINGS: Sleep pattern in mechanically ventilated patients differs largely from physiological sleep. The ventilatory mode and the ventilatory settings could have an influence on the sleep quality and quantity. Pressure support ventilation can increase the sleep fragmentation and decrease the sleep quantity, due to central apneas when compared with assist control ventilation. An excessive level of ventilatory assistance during sleep promotes central apneas and ineffective efforts. These two respiratory events can trigger arousals and awakenings, thus altering the sleep quality and quantity in mechanically ventilated patients. Ventilatory settings adjusted according to the patient's effort during pressure support allow reducing the number of ineffective efforts and improve sleep quality when compared with a clinical adjustment. A physiological approach to set the ventilator and the ventilatory mode may improve sleep quality and quantity. SUMMARY: Minimizing the sleep alterations in mechanically ventilated patients could be obtained by setting the ventilator in such a way to avoid hyperventilation during the sleep stage. The impact of sleep derangements in patient outcomes is, however, unknown.

Parthasarathy S. · Section of Pulmonary, Critical Care and Sleep Medicine, Southern Arizona VA Health Care System and University of Arizona, Tucson, AZ 85723, USA. · J Clin Sleep Med. · Pubmed #18853711 links to  free full text

This publication has no abstract.

Quan SF, Budhiraja R, Parthasarathy S. · Division of Sleep Medicine, Harvard Medical School, Boston, MA 02215, USA. · J Clin Sleep Med. · Pubmed #18595432 links to  free full text

This publication has no abstract.

Ambrogio C, Parthasarathy S. · Southern Arizona VA Health Care System and University of Arizona, Tucson, AZ 85723, USA. · J Clin Sleep Med. · Pubmed #17993049 links to  free full text

This publication has no abstract.

Lu B, Budhiraja R, Parthasarathy S. · Loyola University Medical Center Maywood, IL, USA. · J Clin Sleep Med. · Pubmed #17564403 No free full text.

Abstract: BACKGROUND: Sedative medications may be inadvertently prescribed to patients with undiagnosed obstructive sleep apnea (OSA) and may worsen daytime sleepiness. STUDY OBJECTIVES: To determine whether patients with undiagnosed OSA were prescribed sedative medications and whether such prescriptions increased the risk for traffic accidents. A secondary objective was to determine physician characteristics associated with such prescription practices. DESIGN: Retrospective chart review. Telephone interviews of patients and physicians. INTERVENTION: None. PATIENTS: One hundred fifty-one consecutive patients at a sleep laboratory. RESULTS: Forty-one of 137 (30%) patients with undiagnosed OSA had received prescriptions for sedating medications. Regression analysis identified self-report of sleepiness while driving (p = .05) and prescription for risperidone as independent risk factors for motor vehicle accidents (p = .005), while prescription of any sedative (excluding risperidone) tended to be associated with accidents (p =.10). In patients with severe OSA, prescription of sedating medications was associated with a greater risk for motor vehicle accidents than those without such prescriptions (relative risk = 2.6; p = .04). In patients with prescription for sedating medications (n = 41), the apnea-hypopnea index was directly proportional to the risk for motor vehicle accidents (r2 = 0.26; p = .001) suggesting a 'dose effect' of severity of sleep-disordered breathing on risk for accidents. Physicians who did not usually treat patients with sleep disorders were more likely to prescribe sedatives to patients with undiagnosed OSA than were physicians with such expertise: neurologist, pulmonologist, or psychiatrist (52% vs 10%; relative risk = 5.2; p = .02) CONCLUSION: Prescription of sedating medications may increase the risk of road accidents in patients with undiagnosed severe OSA, and such prescription practices are less likely to occur in physicians with expertise in sleep medicine.

Parthasarathy S. · Southern Arizona VA Health Care System and University of Arizona, Tucson, AZ 85723, USA. · J Clin Sleep Med. · Pubmed #17563937 No free full text.

This publication has no abstract.

Parthasarathy S. · Section of Pulmonary and Critical Care Medicine, SAVAHCS and University of Arizona, Tucson, AZ 85723, USA. · J Clin Sleep Med. · Pubmed #17561638 No free full text.

This publication has no abstract.

Parthasarathy S, Haynes PL, Budhiraja R, Habib MP, Quan SF. · Southern Arizona Veterans Administration Health Care System, Tucson, AZ 85723, USA. · J Clin Sleep Med. · Pubmed #17557485 No free full text.

Abstract: STUDY OBJECTIVES: To study the effect of American Academy of Sleep Medicine accreditation of sleep centers and sleep-medicine certification of physicians on the management of patients with obstructive sleep apnea (OSA). DESIGN: Cross-sectional study. SETTING: National web-based survey. PATIENTS: Six hundred thirty-two patients with OSA. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Self-reported data on details of whether patients with OSA were using positive airway pressure (PAP) devices, timeliness of the initiation of PAP therapy, and overall satisfaction of care received from physicians and centers. After adjusting for covariates, lack of accreditation or certification status of providers was independently associated with discontinuation of PAP therapy (odds ratio [OR] 1.9, 95% confidence interval [CI], 1.1-3.2; p = .03). Patient education leading to perception of risk associated with OSA (OR 0.5, 95% CI, 0.2-0.9) and medications for nasal congestion (OR 0.3, 95% CI, 0.1-0.8) "protected" against discontinuation of PAP therapy, whereas nasal congestion (OR 1.6, 95% Cl, 1.0-2.4) increased the likelihood for discontinuation of PAP therapy. Certified physicians and accredited centers were more likely to educate their patients and received greater satisfaction ratings than non-certified physicians and nonaccredited centers (p < .05). Time delays in instituting PAP therapy were not influenced by accreditation or certification status, but such delays diminished patient satisfaction. CONCLUSIONS: In this web-based survey, accreditation or certification status of sleep centers and physicians was associated with better indexes of clinical management in patients with OSA. Better patient education that fostered risk perception may have been partly responsible for such an association. Prospective studies designed to collect objective data regarding the effect of accreditation or certification status on outcomes in patients with OSA are still needed.

Parthasarathy S. · Southern Arizona Veterans Administration Health Care System, Tuscon, AZ 85723, USA. · J Clin Sleep Med. · Pubmed #17557479 No free full text.

This publication has no abstract.

Budhiraja R, Parthasarathy S, Drake CL, Roth T, Sharief I, Budhiraja P, Saunders V, Hudgel DW. · Section of Pulmonary & Critical Care, Southern Arizona Veterans Affairs Health Care System (SAVAHCS), 3601 South 6th Avenue, Tucson, AZ 85723, USA. · Sleep. · Pubmed #17425228 No free full text.

Abstract: STUDY OBJECTIVES: To explore the relationship between specific factors such as sex and early continuous positive airway pressure (CPAP) use, and 30-day adherence to CPAP therapy. DESIGN AND SETTING: Retrospective study conducted at a single center in southeast Michigan. PATIENTS: One hundred patients with obstructive sleep apnea who were recently initiated on CPAP therapy with electronic adherence information relayed from the CPAP device to a laboratory-based computer through telephone modem. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: An empiric threshold value of objective CPAP use of greater than 4 hours per night measured 3 days following CPAP initiation was predictive of level of CPAP adherence measured 30 days later. Furthermore, CPAP adherence was directly proportional to age (R = 0.25, P = .018). There were no sex-related differences in adherence to CPAP therapy. CONCLUSIONS: Long-term adherence to CPAP therapy can be predicted as early as 3 days following CPAP initiation. The study also demonstrates that younger age and African-American race are independently associated with lower CPAP adherence.

Fitzgerald MP, Mulligan M, Parthasarathy S. · Division of Female Pelvic Medicine and Reconstructive Surgery, Loyola University Medical Center, Maywood, IL, USA. · Am J Obstet Gynecol. · Pubmed #16579944 No free full text.

Abstract: OBJECTIVE: The purpose of this study was to determine the relationship between nocturia and obstructive sleep apnea (OSA), and the effect of continuous positive airways pressure (CPAP) therapy on nocturic frequency. STUDY DESIGN: This was a retrospective review of sleep studies including patients with and without evidence of OSA, before and during CPAP treatment (where relevant). Chi-squared tests compared nocturia prevalence according to sleep diagnosis, logistic regression determined predictors of nocturia, and regression analyses determined predictors of nocturic frequency. RESULTS: In 196 eligible studies, predictors of nocturia included increasing age and diabetes mellitus; nocturia was equally likely to occur in patients with and without OSA. In patients with OSA and nocturia, nocturic frequency was related to age, diabetes, and severity of OSA (P < .001). Patients with OSA and nocturia who were treated with CPAP demonstrated a significant decrease in nocturic frequency (P < .001). CONCLUSION: OSA severity predicts nocturic frequency. The role of testing in the triage of patients with nocturia remains to be determined.

Budhiraja R, Goodwin JL, Parthasarathy S, Quan SF. · Division of Pulmonary & Critical Care, Department of Medicine, Southern Arizona Veterans Affairs Health Care System, Tucson, AZ 85723, USA. · Sleep. · Pubmed #16268381 No free full text.

Abstract: STUDY OBJECTIVES: The results of small studies have suggested that a nasal-cannula pressure transducer has a higher sensitivity than a thermistor in detecting hypopneas and diagnosing sleep-disordered breathing in both adults and children. We compared a thermistor alone, and in conjunction with a pressure transducer, for detection of sleep-disordered breathing in children during in-home polysomnography. DESIGN: Retrospective analysis of a subsample of a prospective cohort study. SETTING: Students attending elementary school in the Tucson Unified School District. PARTICIPANTS: A subsample of the Tucson Children's Assessment of Sleep Apnea study population. MEASUREMENTS AND RESULTS: Polysomnographic recordings of 40 children (24 girls and 16 boys, mean age 9.2 +/- 1.7 years; range 6-11 years) were analyzed to compare the detection of sleep-disordered breathing events by 2 different methods of measuring airflow: thermistor alone and thermistor with nasal-cannula pressure transducer (transducer) used simultaneously. The transducer detected all the respiratory events detected by the thermistor, but the thermistor detected only 84% of the transducer-defined events. Consequently, the transducer-derived mean respiratory disturbance index was higher than that detected by the thermistor (7.0 +/- 3.8 vs 5.9 +/- 3.4, P < .001). The bias error between transducer respiratory disturbance index and thermistor respiratory disturbance index on a Bland-Altman plot was 1.08 (95% confidence interval, 0.8 - 1.4). There was good agreement between the thermistor and the transducer for making the diagnosis of sleep apnea using a cutoff of a respiratory disturbance index greater than 5 (kappa = 0.69). The quality of the tracings with the transducer was comparable to that of the thermistor, but the transducer dislodged more frequently. CONCLUSION: The use of a nasal transducer in conjunction with a thermistor was more sensitive than the thermistor alone in detecting sleep-disordered breathing in children during unattended polysomnography.

Parthasarathy S, Tobin MJ. · Division of Pulmonary and Critical Care Medicine, Edward Hines, Jr. Veterans Administrative Hospital, Illinois 60141, USA. · Am J Respir Crit Care Med. · Pubmed #12406837 links to  free full text

Abstract: To determine whether sleep quality is influenced by the mode of mechanical ventilation, we performed polysomnography on 11 critically ill patients. Because pressure support predisposes to central apneas in healthy subjects, we examined whether the presence of a backup rate on assist-control ventilation would decrease apnea-related arousals and improve sleep quality. Sleep fragmentation, measured as the number of arousals and awakenings, was greater during pressure support than during assist-control ventilation: 79 +/- 7 versus 54 +/- 7 events per hour (p = 0.02). Central apneas occurred during pressure support in six patients; heart failure was more common in these six patients than in the five patients without apneas: 83 versus 20% (p = 0.04). Among patients with central apneas, adding dead space decreased sleep fragmentation: 44 +/- 6 versus 83 +/- 12 arousals and awakenings per hour (p = 0.02). Changes in sleep-wakefulness state caused greater changes in breath components and end-tidal CO2 during pressure support than during assist-control ventilation. In conclusion, inspiratory assistance from pressure support causes hypocapnia, which combined with the lack of a backup rate and wakefulness drive can lead to central apneas and sleep fragmentation, especially in patients with heart failure.