Use of bilevel positive airway pressure (BIPAP) in end-stage patients with cystic fibrosis awaiting lung transplantation.

Nine consecutive end-stage patients with cystic fibrosis (CF) awaiting lung transplantation were admitted to the pediatric intensive care unit (PICU) in respiratory decompensation. They all received noninvasive bilevel positive airway pressure (BIPAP) support and were evaluated to determine whether or not it improved their oxygenation and provided them with long-term respiratory stability. BIPAP was applied to all patients after a brief period of assessment of their respiratory status. Inspiratory and expiratory positive airway pressures (IPAP, EPAP) were initially set at 8 and 4 cm H2O respectively. IPAP was increased by increments of 2 cm H2O and EPAP was increased by 1 cm H2O increments until respiratory comfort was achieved and substantiated by noninvasive monitoring. Patients were observed in the PICU for 48 to 72 hours and then discharged to home with instructions to apply BIPAP during night sleep and whenever subjectively required. Regular follow-up visits were scheduled through the hospital-based CF clinic. The patients' final IPAP and EPAP settings ranged from 14 to 18 cm H2O and 4 to 8 cm H2O, respectively. All nine patients showed a marked improvement in their respiratory status with nocturnal use of BIPAP at the time of discharge from the PICU. Their oxygen requirement dropped from a mean of 4.6 +/- 1.1 L/min to 2.3 +/- 1.5 L/min (P < 0.05). Their mean respiratory rate decreased from 34 +/- 4 to 28 +/- 5 breaths per minute (P < 0.05). The oxygen saturation of hemoglobin measured by pulse oximetry, significantly increased from a mean of 80% +/- 15% to 91% +/- 5% (P < 0.05). The patients have been followed up for a period of 2 to 43 months and have all tolerated the use of home nocturnal BIPAP without any reported discomfort. Six patients underwent successful lung transplantation after having utilized nocturnal BIPAP for 2, 6, 14, 15, 26, and 43 months, respectively. Three patients have utilized home BIPAP support for 2, 3, and 19 months, respectively, and continue to await lung transplantation. An acute development of refractory respiratory failure resulted in the demise of the remaining three patients after having utilized BIPAP for 3, 6, and 10 months, respectively. The authors conclude that BIPAP therapy improves the respiratory status of decompensating end-stage CF patients. It is well tolerated for long-term home use and provides an extended period of respiratory comfort and stability for CF patients awaiting lung transplantation.

Clinical spectrum in homozygotes and compound heterozygotes inheriting cystic fibrosis mutation 3849 + 10kbC > T: significance for geneticists.

We describe patients inheriting cystic fibrosis (CF) mutation 3849 + 10kb > T as homozygotes or compound heterozygotes. Three unrelated homozygotes for this mutation were all pancreatic-sufficient and sweat test-negative or inconclusive. Among the compound heterozygotes, both pancreatic sufficiency and insufficiency, as well as positive and negative/inconclusive sweat test results are reported, expanding the range of clinical expression associated with inheritance of this mutation. 3849 + 10kbC > T is one of several CF mutations that can result in atypical or variant forms of CF. For geneticists, the diagnosis of variant CF has implications for recurrence risk and prognosis counseling of the families of affected individuals, and possibly for CF carrier screening in the general population.

A novel mutation in the cystic fibrosis gene in patients with pulmonary disease but normal sweat chloride concentrations.

BACKGROUND: Many patients with chronic pulmonary disease similar to that seen in cystic fibrosis have normal (or nondiagnostic) sweat chloride values. It has been difficult to make the diagnosis of cystic fibrosis in these patients because no associated mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene has been identified. METHODS: We evaluated 23 patients with pulmonary disease characteristic of cystic fibrosis but with sweat chloride concentrations in the normal range. Mutations in the CFTR gene were sought by direct sequencing of polymerase chain reaction-amplified nasal epithelial messenger RNA and by testing the functioning of affected epithelium. RESULTS: A cytidine phosphate guanosine dinucleotide C-to-T point mutation in intron 19 of the CFTR gene, termed 3849 + 10 kb C to T, was identified in 13 patients from eight unrelated families. This mutation was found in patients from three different ethnic groups with three different extended haplotypes. The mutation leads to the creation of a partially active splice site in intron 19 and to the insertion into most CFTR transcripts of a new 84-base-pair "exon," containing an in-frame stop codon, between exons 19 and 20. Normally spliced transcripts were also detected at a level approximately 8 percent of that found in normal subjects. This mutation is associated with abnormal nasal epithelial and sweat acinar epithelial function. CONCLUSIONS: We have identified a point mutation in intron 19 of CFTR and abnormal epithelial function in patients who have cystic fibrosis-like lung disease but normal sweat chloride values. The identification of this mutation indicates that this syndrome is a form of cystic fibrosis. Screening for the mutation should prove diagnostically useful in this population of patients.

Pancolonic disease in cystic fibrosis and high-dose pancreatic enzyme therapy.

We describe a child with cystic fibrosis who was treated with high-dose pancreatic enzyme replacement therapy and who had a prominent ascending colon stricture with submucosal fibrosis. Unlike prior reported cases, this patient's disease was more extensive, involving the entire colon, and was associated with chylous ascites.

Quantitative deposition of aerosolized gentamicin in cystic fibrosis.

In cystic fibrosis (CF), the clinical effectiveness of aerosolized antibiotics is controversial. Previous investigators have not considered the type of nebulizer, droplet size, and dose to the lung in assessing the results of aerosol therapy. The present study tests the importance of these factors by standardizing an aerosol system for delivery of antibiotics and other agents to patients with CF. Particle size, distribution, and output from a commercially available nebulizer were measured. Thirteen patients with CF inhaled aerosol (MMAD = 1.1 micron) containing gentamicin (160 mg in nebulizer) and 99mTc-labeled human serum albumin. Patients' sputum and serum were analyzed for gentamicin levels by immunoenzymatic assay (Emit; Syva Corp., Palo Alto, CA). Using a gamma camera and suitable filters, central versus peripheral deposition (C/P ratio) and whole lung deposition were measured and related to sputum gentamicin levels. Gentamicin deposit averaged 12.3 mg +/- 5.9 (SD) or 7.69% of the original amount placed in the nebulizer. Peak sputum levels averaged 376.6 micrograms/ml +/- 275, whereas serum levels were undetectable in all patients. When peak sputum levels were normalized for the amount deposited, a close correlation with C/P ratio was obtained (r = 0.88, p less than 0.05). Furthermore, an inverse relationship was found between the C/P ratio and the %FEV1 (r = 0.76, p less than 0.05). Finally, a bell-shaped relationship between deposited dose and minute ventilation was seen in the patients (r = 0.88, p less than 0.05), i.e., an optimal minute ventilation was shown. These relationships may be important when designing future clinical studies.

Portal vein measurement by ultrasonography in patients with long-standing cystic fibrosis: preliminary observations.

Adult cystic fibrosis (CF) patients are increasingly diagnosed with hepatic cirrhosis, cholecystitis, and cholelithiasis. A continuing diagnostic problem is the early detection of cirrhosis prior to diffuse liver involvement. Sonography has been used in evaluating the pancreas, gallbladder, liver, and spleen in cystic fibrosis patients. We used a real-time mechanical sector scanner to study the portal veins in adult CF patients randomly selected from our CF population and correlated the portal vein diameters with liver function studies. A measurement greater than 12 mm was interpreted as a probable sign of portal hypertension. Of 21 patients studied, 14 had portal veins that measured greater than 12 mm, and 12 patients had (although not necessarily at the time of the exam) elevated serum alkaline phosphatase levels. Three patients had associated splenomegaly and thrombocytopenia, and 10 patients also exhibited cholelithiasis and abnormal gallbladders on sonography. Initial results indicate that portal vein measurement may be a sensitive indicator of early portal hypertension. Sonography may, thus, isolate patients at high risk for possible future complications. Serial sonograms can be performed easily in evaluating the progress of liver disease.

Cystic fibrosis and hearing loss.

The mucosal epithelium of the middle ear and Eustachian tube is in direct continuity with the upper respiratory tract. Since the otolaryngological aspects of cystic fibrosis (CF) are dominated by involvement of the paranasal sinuses, it might be assumed that children with CF would be expected to have a higher than usual incidence of middle ear disease. Eighty patients who were afflicted with CF had audiological evaluations, which consisted of hearing threshold levels (250 to 8,000 Hz) and speech and impedance audiometry. We found no greater incidence of a conductive or sensorineural hearing loss in patients with CF when compared with a normal age-adjusted population.