Mary H. Wagner

Barriers to adherence to cystic fibrosis infection control guidelines

In 2003, the American Cystic Fibrosis (CF) Foundation published revised, evidence‐based guidelines for infection control. We sought to assess potential barriers to adherence to these guidelines experienced by health care professionals (HCPs) caring for CF patients.

Ranitidine and omeprazole as adjuvant therapy to pancrelipase to improve fat absorption in patients with cystic fibrosis.

Background Inadequate treatment of pancreatic insufficiency in patients with cystic fibrosis (CF) causes malabsorption of nutrients with significant sequelae. The objective of this study was to measure the effect of acid suppressant therapy on fat absorption in patients with CF who received a pH-sensitive, enteric-coated microtablet enzyme product. Methods A double-blind, placebo-controlled crossover study of 12 children and 10 adults with pancreatic insufficient CF was performed. All subjects were receiving pancrelipase therapy (Pancrease MT10 and MT16; Ortho-McNeil, Springhouse, PA, U.S.A.) and for the study also received either placebo or ranitidine (Zantac; Glaxo-Wellcome, Research Triangle Park, NC U.S.A.) 5 mg/kg or 10 mg/kg daily. The adult subjects also received omeprazole therapy (Prilosec; AstraZeneca/Merck, Wilmington, DE, U.S.A.), 20 mg daily, as adjuvant therapy to pancreatic enzymes. Serial 3-day fat-balance studies were performed in the Clinical Research Center. The data were analyzed using individual paired t tests that compared each treatment with placebo and two repeated-measures, general linear model F tests. Results The linear model for all subjects showed no overall adjuvant drug effect on fat absorption, P = 0.32. A second linear model F test analysis of adult subjects, comparing all four drug treatments (placebo, ranitidine 5 and 10 mg/kg daily and omeprazole), also showed no difference in fat absorption, P = 0.15. Paired t test subgroup analysis of the adults showed an improvement of 4.97% (P = 0.003) in mean fat absorption comparing low-dose ranitidine to placebo. All other t test analyses showed no significant change in fat absorption between placebo and acid suppressant treatment. There was marked intersubject and intrasubject variability in fat absorption. Conclusions No overall significant improvement in fat absorption could be demonstrated with adjuvant therapy. Fat absorption measured by 3-day fat-balance studies varied greatly even when comparing the same subject for placebo and baseline treatments, despite identical dietary fat and enzyme intakes. The large variability limited our ability to test for a difference in fat absorption and has significant implication for the use of this test, considered the gold standard, for determining enzyme dosage adequacy.

Altered copper status in adult men with cystic fibrosis.

OBJECTIVES To measure indices of copper status in adult men with cystic fibrosis (CF). A previous study in children showed changes in copper homeostasis compared to controls. This study was designed to investigate whether this observation persisted into adulthood. METHODS This was a case-control age-matched study using seven men with CF and six healthy men. Blood samples were drawn into metal free tubes and fractionated into plasma, polymorphonuclear cells, mononuclear cells and erythrocytes. Cell fractions were assayed for copper and CuZn-superoxide dismutase; plasma was assayed for ceruloplasmin. RESULTS The men with cystic fibrosis had significantly greater plasma copper and ceruloplasmin activity, yet had significantly lower copper-zinc superoxide dismutase activity in mononuclear and polymorphonuclear cells. Furthermore, the mononuclear cells of the cystic fibrosis subjects had about 45% percent less copper-zinc superoxide dismutase protein. Cellular copper levels were not statistically different between the two groups. A significant correlation was found between lung function and copper-zinc superoxide dismutase activity in the polymorphonuclear cells. Iron status was normal. CONCLUSIONS The results indicate that individuals with cystic fibrosis have altered copper distribution compared to control individuals. Some aspects are characteristic of an inflammatory response; however, other measures suggest that copper homeostasis may be abnormal. It is not known whether the deviation in copper homeostasis in these individuals is a result of poor copper absorption, inadequate dietary intake, a result of their chronic inflammation or a direct effect due to the defect in ion transport caused by the disease. However, this research suggests that the severity of the disease and the activity of a copper dependent enzyme may be related. Further work will be necessary to determine the cause of the abnormal copper homeostasis and whether correcting it has any bearing on the course of the disease.

Effect of vitamin E deficiency on neurologic function in patients with cystic fibrosis

We evaluated neurologic function in 18 patients, ages 5 to 26 years, with cystic fibrosis. Eight were deficient in vitamin E. Sural nerve conduction latency was increased and nerve action potential amplitude decreased in the vitamin E-deficient group in comparison with the vitamin E-sufficient group. Two vitamin E-deficient patients had absent deep tendon reflexes; findings of clinical neurologic examinations were otherwise normal. We recommend early supplementation with vitamin E for patients with cystic fibrosis who have pancreatic insufficiency, to prevent neurologic dysfunction.

Barriers to treatment of paediatric obstructive sleep apnoea: Development of the adherence barriers to continuous positive airway pressure (CPAP) questionnaire

BACKGROUND Continuous positive airway pressure (CPAP) treatment is often prescribed for youth as a treatment for obstructive sleep apnoea (OSA). Efficacy research in youth is limited, though some evidence suggests that it may relieve symptoms of OSA and possibly prevent future physical, emotional, and behavioural complications. However, the device must be used consistently for benefits to be realised. Non-adherence to medical treatment is prevalent among youth with chronic illness, yet little is known regarding adherence to CPAP in paediatric OSA. METHODS Using a sample of 51 youth (age 8-17 years) recruited from a paediatric sleep specialty clinic, the aims of the current study were to: (1) present descriptive data regarding CPAP adherence in youth with OSA, and (2) develop a psychometrically sound measure of barriers for adherence to CPAP use for youth with OSA. RESULTS Results indicated that adherence to CPAP is poor: youth in the current sample used their CPAP on average 3.35 h per night. The adherence barriers measure demonstrated excellent psychometric properties. CONCLUSIONS The adherence barriers to CPAP questionnaire has the potential to be a useful clinic-based tool for identifying patient-specific issues with CPAP adherence in youth with OSA.

Prader-Willi Syndrome and Sleep-Disordered Breathing

Prader-Willi Syndrome is a complex neurogenetic disorder characterized by appetite dysregulation, obesity with decreased muscle mass and increased fat mass, behavioral problems, various endocrinopathies, and sleep and respiratory abnormalities. Respiratory issues include both central and obstructive sleep apnea, excessive daytime sleepiness, narcolepsy, and impaired ventilatory control. There is some controversy as to whether growth hormone treatment, which is the standard of care for patients with Prader-Willi Syndrome, exacerbates or ameliorates the sleep-disordered breathing issues associated with this syndrome. The natural history of sleep and breathing issues and the issues surrounding growth hormone treatment on sleep-disordered breathing are discussed.

Comparison of steatocrit and fat absorption in persons with cystic fibrosis

Background Exocrine pancreatic insufficiency is a common problem in persons with cystic fibrosis causing malabsorption and poor growth. The 72-hour fecal fat study is the best qualitative measure of fat malabsorption used in clinical practice. This test has several drawbacks, which include cost and logistics. The steatocrit has been proposed as a rapid method to assess fat malabsorption. Objectives The objective of this study was to determine whether the steatocrit is an accurate estimation of fat malabsorption in persons with cystic fibrosis. Methods Forty-nine stool samples for steatocrit processing were obtained from 72-hour fecal fat collections performed on twenty-seven persons with cystic fibrosis. Stools were weighed and homogenized with sand and water. The emulsified specimen was pipetted into heparinized capillary tubes and centrifuged for 15 minutes. The length of the fatty layer was compared to the length of the solid layer plus the fatty layer in each tube to determine the steatocrit value. Four steatocrit mixtures were evaluated: (1) standard steatocrit, (2) dilute steatocrit, (3) acid steatocrit, (4) dilute acid steatocrit. Steatocrit values were compared with the coefficient of fat absorption determined from the 72-hour fecal fat collection. Results The correlation coefficient of the steatocrit and the coefficient of fat absorption ranged from -.045 to -.491. Only the coefficient of fat absorption and the acid steatocrit had a significant correlation (P = 0.033). Conclusion The steatocrit is an imprecise measure of fat absorption and not clinically useful in estimating steatorrhea.

Use of Chest Wall Electromyography to Detect Respiratory Effort during Polysomnography

STUDY OBJECTIVES To evaluate the ability of chest wall EMG (CW-EMG) using surface electrodes to classify apneas as obstructive, mixed, or central compared to classification using dual channel uncalibrated respiratory inductance plethysmography (RIP). METHODS CW-EMG was recorded from electrodes in the eighth intercostal space at the right mid-axillary line. Consecutive adult clinical sleep studies were retrospectively reviewed, and the first 60 studies with at least 10 obstructive and 10 mixed or central apneas and technically adequate tracings were selected. Four obstructive and six central or mixed apneas (as classified by previous clinical scoring) were randomly selected. A blinded experienced scorer classified the apneas on the basis of tracings showing either RIP channels or the CW-EMG channel. The agreement using the two classification methods was determined by kappa analysis and intraclass correlation. RESULTS The percentage agreement was 89.5%, the kappa statistic was 0.83 (95% confidence interval 0.79 to 0.87), and the intraclass correlation was 0.83, showing good agreement. Of the 249 apneas classified as central by RIP, 26 were classified as obstructive (10.4%) and 7 as mixed (2.8%) by CW-EMG. Of the 229 events classified as central by CW-EMG, 7 (3.1%) were classified as obstructive and 6 (2.6%) as mixed by RIP. CONCLUSIONS Monitoring CW-EMG may provide a clinically useful method of detection of respiratory effort when used with RIP and can prevent false classification of apneas as central. RIP can rarely detect respiratory effort not easily discernible by CW-EMG and the combination of the two methods is more likely to avoid apnea misclassification.

Use of Chest Wall EMG to Classify Hypopneas as Obstructive or Central

STUDY OBJECTIVES To compare classification of hypopneas as obstructive or central based on an effort signal derived from surface chest wall electromyography (CW-EMG-EF) coupled with airflow amplitude versus classification using The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications (AASM Scoring Manual) criteria; and to characterize hypopneas classified as obstructive versus central using a resistance surrogate. METHODS CW-EMG was recorded in the eighth intercostal space at the right midaxillary line. Five hypopneas were randomly selected from 65 consecutive adult clinical positive airway pressure titration studies meeting study criteria. A blinded scorer classified the hypopneas based on two groups of signals: Group 1: positive airway pressure flow (PAP flow), chest and abdominal effort, and snoring; or Group 2: smoothed PAP flow (for blinding amplitude but not flattening visible) and effort (CW-EMG-EF). A resistance surrogate (CW-EMG-EF / PAP flow) normalized to a pre-event breath was compared between obstructive and central hypopneas classified by AASM Scoring Manual criteria. RESULTS The percentage agreement (Group 1 versus Group 2) was 92% and the kappa was 0.75 (95% confidence interval 0.65 to 0.85). The resistance surrogate was significantly higher in obstructive hypopneas versus central hypopneas during the first and second half of hypopneas. The resistance surrogate (mean ± standard deviation) for the second half of hypopnea was obstructive: 7.59 ± 7.24 versus central: 1.27 ± 0.56, P < .001). The resistance surrogate increased from the first to second half of hypopnea only for obstructive hypopneas. CONCLUSIONS CW-EMG provides a useful complementary signal for hypopnea classification and a resistance surrogate based on CW-EMG is much higher in hypopneas classified as obstructive by AASM Scoring Manual criteria.

A Patient With Suspicious Oxygen Desaturations at Sleep Onset

Journal of Clinical Sleep Medicine, Vol. 14, No. 8 August 15, 2018 Your sleep tech asks you to check on the veracity of oxygen desaturations noted prior to sleep onset in a child who presented for a sleep study to evaluate the family’s reports of apneic events. The patient is a 2-year-old female who was referred by a pediatric neurologist for further evaluation of the family’s reports of apnea noted prior to sleep onset. The child was developing normally until approximately 6 months prior when she began to have regression of language and developed unusual hand movements. Physical examination was most remarkable for mild decrease in head circumference with child noted to be SLEEP MEDICINE PEARLS