Chest
Contemporary Reviews in Sleep MedicineObesity Hypoventilation Syndrome: Weighing in on Therapy Options
Section snippets
Why Does OHS Occur?
On first consideration, it may seem obvious that changes in lung mechanics associated with obesity would explain the emergence of daytime hypoventilation through simple changes in ventilation. Individuals with OHS exhibit more pronounced decreases in lung volumes, more impaired respiratory muscle performance, and greater reductions in respiratory system compliance compared to those with eucapnic obesity.5 These changes are at least in part attributable to a more central pattern of fat
Consequences of OHS
The early identification and treatment of OHS is considered crucial given the significant health and social consequences experienced by these individuals. Systemic inflammation, endothelial dysfunction, and insulin resistance are more pronounced in people with OHS compared with eucapnic obesity,21 resulting in the development of an array of cardiovascular and metabolic morbidities some years prior to definitive diagnosis and treatment.3 Pulmonary hypertension is both more prevalent and of
Screening and Diagnosis of OHS
Given the high morbidity and mortality associated with OHS compared with eucapnic obesity with or without OSA, recognition and early intervention is considered critical. The prevalence of OHS in the general population is currently unknown, although estimates based on obesity and OSA rates suggest 0.3% to 0.48% of the general adult population may be affected.31, 32 Among obese individuals, the prevalence of OHS ranges from around 8% in premenopausal women being evaluated for bariatric surgery33
Treatment Options
The goals of therapy in OHS are to reverse the major physiologic abnormalities giving rise to the disorder, namely to normalize breathing during sleep, reduce weight, and improve respiratory drive. PAP therapy remains firstline treatment, providing the most immediate improvements in nocturnal gas exchange. However, the impact of PAP therapy on cardiovascular complications and mortality in OHS appears limited, highlighting the importance of a more comprehensive long-term management approach in
PAP Therapy
The goal of PAP therapy in stable OHS is to normalize breathing during sleep, consolidate sleep, and improve nocturnal gas exchange. Since upper airway obstruction is very common in OHS, not surprisingly, CPAP therapy effectively controls sleep-disordered breathing and reverses daytime respiratory failure in 50% to 80% of individuals presenting to sleep laboratories.20, 31, 53 In addition to maintaining upper airway patency, the volume-inflating effect of CPAP improves oxygenation through
Managing Acute Respiratory Failure
While the majority of patients with OHS present through respiratory and sleep clinics with chronic respiratory failure, 30% to 70% of individuals will be first diagnosed during an acute hospitalization with respiratory decompensation.29, 60, 69 Unfortunately, it may take a number of acute presentations before a correct diagnosis and appropriate management plan is put in place.9, 26 No randomized trials comparing different forms of PAP therapy for decompensated respiratory acidosis have been
Weight Loss
Significant improvements in awake CO2 and lung volumes can be achieved with sufficient weight loss,73 and a weight reduction program should be incorporated into the long-term management of individuals with OHS. Surgical approaches are more effective than conservative options in maximizing and maintaining weight loss.74 Although few studies have specifically enrolled patients with OHS undergoing bariatric surgery, significant improvements in gas exchange, sleep apnea, lung volumes, and pulmonary
Tracheostomy
Nowadays, tracheostomy is rarely used for the treatment of OHS although it should be considered for patients intolerant of PAP therapy and where other treatment options such as significant weight loss are not feasible. Significant risks and complications are associated with tracheostomy in the morbidly obese including obstruction of the tube by soft tissue and displacement of the tube out of the tracheal lumen, in addition to the usual physical and social consequences of tube placement. Few
Pharmacotherapy
Improved respiratory drive can be achieved pharmacologically and there are a small number of reports of respiratory stimulants being used successfully in the short-term. In postmenopausal women with sleep-disordered breathing, 2 weeks of medroxyprogesterone improved nocturnal oxygen saturation and reduced CO2 compared with a placebo group.80 Furthermore, CO2 was lower than when the subjects were using overnight CPAP, with stimulatory effects maintained at least 3 weeks after ceasing medication.
Conclusions
OHS is a complex, multifactorial disorder necessitating a comprehensive management approach. Although PAP therapy can effectively abolish sleep-disordered breathing, unload the respiratory muscles, reduce the work of breathing, and improve ventilatory drive, it appears to have little impact on the excess cardiovascular risk and comorbidity associated with persisting obesity.28, 52 As OHS is associated with a more extreme inflammation and greater endothelial dysfunction than eucapnic obesity,21
Acknowledgments
Financial/nonfinancial disclosures: A. P. has received speaking fees from ResMed, Philips Respironics (Koninklijke Philips NV), Novartis AG, and SenTec AG and reimbursement for travel costs from SenTec AG. A. P. also received a grant from the ResMed Foundation to study PAP therapy in obesity hypoventilation syndrome.
References (81)
- et al.
National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9.1 million participants
Lancet
(2011) Bicarbonate or base excess in early obesity hypoventilation syndrome: a methodologic viewpoint
Chest
(2015)Obesity hypoventilation syndrome–the big and the breathless
Sleep Med Rev
(2011)- et al.
Obesity-associated hypoventilation in hospitalized patients: prevalence, effects, and outcome
Am J Med
(2004) - et al.
Relationship of dyspnea to respiratory drive and pulmonary function tests in obese patients before and after weight loss
Chest
(2005) - et al.
Impaired objective daytime vigilance in obesity-hypoventilation syndrome: impact of noninvasive ventilation
Chest
(2007) - et al.
Decreased hypoxic ventilatory drive in the obesity-hypoventilation syndrome
Am J Med
(1975) - et al.
Pleiotropic role of IGF-I in obesity hypoventilation syndrome
Growth Horm IGF Res
(2010) - et al.
Determinants of hypercapnia in obese patients with obstructive sleep apnea: a systematic review and metaanalysis of cohort studies
Chest
(2009) - et al.
The obesity-hypoventilation syndrome revisited: a prospective study of 34 consecutive cases
Chest
(2001)
Pulmonary hypertension in obesity-hypoventilation syndrome
Respir Med
Obesity hypoventilation syndrome: hypoxemia during continuous positive airway pressure
Chest
Daytime hypercapnia in obstructive sleep apnea syndrome
Chest
Is a raised bicarbonate, without hypercapnia, part of the physiologic spectrum of obesity-related hypoventilation?
Chest
Noninvasive mechanical ventilation in patients with obesity hypoventilation syndrome. Long-term outcome and prognostic factors
Arch Bronconeumol
Noninvasive positive pressure ventilation and not oxygen may prevent overt ventilatory failure in patients with chest wall diseases
Chest
Respiratory patterns during sleep in obesity-hypoventilation patients treated with nocturnal pressure support: a preliminary report
Chest
Noninvasive ventilation in mild obesity hypoventilation syndrome: a randomized controlled trial
Chest
Average volume-assured pressure support in obesity hypoventilation: a randomized crossover trial
Chest
Impact of different backup respiratory rates on the efficacy of noninvasive positive pressure ventilation in obesity hypoventilation syndrome: a randomized trial
Chest
The effect of supplemental oxygen on hypercapnia in subjects with obesity-associated hypoventilation: a randomized, crossover, clinical study
Chest
Long-term outcome of noninvasive positive pressure ventilation for obesity hypoventilation syndrome
Chest
Analysis of withdrawal from noninvasive mechanical ventilation in patients with obesity-hypoventilation syndrome. Medium term results [in Spanish]
Arch Bronconeumol
Impact of volume targeting on efficacy of bi-level non-invasive ventilation and sleep in obesity-hypoventilation
Respir Med
Nasal continuous positive airway pressure in decompensated hypercapnic respiratory failure as a complication of sleep apnea
Chest
Current concepts in the pathogenesis of the obesity-hypoventilation syndrome. Mechanical and circulatory factors
Am J Med
Long-term effects of gastric surgery for treating respiratory insufficiency of obesity
Am J Clin Nutr
Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient–2013 update: cosponsored by American Association of Clinical Endocrinologists, the Obesity Society, and American Society for Metabolic & Bariatric Surgery
Surg Obes Relat Dis
Comparison of results after one year between sleeve gastrectomy and gastric bypass in patients with BMI≥50 kg/m2
Surg Obes Relat Dis
Obesity hypoventilation syndrome: Does the current definition need revisiting?
Thorax
Morbidity prior to a diagnosis of sleep-disordered breathing: a controlled national study
J Clin Sleep Med
Observational study of the effect of obesity on lung volumes
Thorax
Work of breathing in eucapnic and hypercapnic sleep apnea syndrome
Respiration
Respiratory determinants of diurnal hypercapnia in obesity hypoventilation syndrome. What does weight have to do with it?
Ann Am Thorac Soc
Obesity hypoventilation syndrome
Semin Respir Crit Care Med
Hypercapnia and ventilatory periodicity in obstructive sleep apnea syndrome
Am J Respir Crit Care Med
Postevent ventilation as a function of CO(2) load during respiratory events in obstructive sleep apnea
J Appl Physiol (1985)
Association of serum leptin with hypoventilation in human obesity
Thorax
Hypoxia impairs the arousal response to external resistive loading and airway occlusion during sleep
Sleep
Impact of adherence with positive airway pressure therapy on hypercapnia in obstructive sleep apnea
J Clin Sleep Med
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