Postural changes in nasal and pulmonary resistance in subjects with asthma.

INTRODUCTION: Subjects with asthma frequently have nasal symptoms and complain of orthopnoea but airflow resistance is usually only assessed during oral breathing and while seated. METHOD: We have used a forced oscillation technique to measure total respiratory resistance (Rrs) at 6Hz during mouth breathing (Rrs,mo) and during nose breathing (Rrs,na) in the sitting and supine postures; resistance of the nasal airway (Rnaw) was estimated as Rrs,na--Rrs,mo. Forced oscillations were applied during normal tidal breathing and the mid-tidal lung volume (MTLV) was determined for each breathing route and posture. SUBJECTS: Three groups of subjects were studied: 10 normal subjects without lung or nasal disease (N; five males, mean age 33.5 [range 23-58] years, mean FEV1 105%pred, FEV1/VC 86%); seven subjects with asthma alone (A; four males, 40.3 [23-57] years, mean FEV1 66%pred, FEV1/VC 74%); 10 asthmatic subjects with nasal obstructive symptoms (AN; six males, 62.8 [38-80] years, mean FEV1 56%pred, FEV1/VC 75%). RESULTS: In all three groups of subjects, mean Rrs,mo and Rrs,na were higher in the supine than sitting posture. In normal subjects the increase in supine Rrs,mo was associated with a 0.6 liter fall in MTLV. In asthma supine Rrs,mo increased despite a much smaller fall in MTLV; supine increases in Rrs,na were particularly large in presence of nasal disease. DISCUSSION: Values of airflow resistance are 2-3 times higher in both normal and asthmatic subjects when breathing via the nose and supine than under normal laboratory conditions of oral breathing and seated.

The efficacy of an antibiotic protocol for community-acquired pneumonia.

OBJECTIVE: To assess the efficacy of an antibiotic protocol to avoid empirical use of third-generation cephalosporins in community-acquired pneumonia (CAP). DESIGN AND SETTING: Retrospective case review of patients with CAP one year after implementing the protocol. Comparison was made with patients with CAP treated at a metropolitan tertiary referral hospital (where use of third-generation cephalosporins was common). PARTICIPANTS: 86 patients (district hospital with an antibiotic protocol) and 72 patients (metropolitan tertiary referral hospital), January - June 1999. OUTCOME MEASURES: Rate of staff adherence to the protocol; patient characteristics associated with poor protocol adherence; demographic and prognostic features of both groups at presentation; duration of intravenous therapy, time to defervescence, length of stay; inpatient mortality rates; and drug cost savings per patient treated according to the protocol. RESULTS: Overall protocol adherence rate was 60%. Patients with penicillin allergy were significantly less likely to receive treatment according to the protocol (P<0.001). At the district hospital, patients were generally older and taking more regular medications. Patients at each hospital had similar prognostic factors and demographic features at presentation. Inhospital mortality (P=0.92; 95% CI, -0.08 to 0.07), duration of fever (P=0.57) and length of stay (P=0.78) were not significantly different between patients treated empirically with penicillin and those treated empirically with third-generation cephalosporins. Treating a patient according to the protocol saved an average of $77.44 in drug costs. CONCLUSION: One year after implementation, our protocol for treating CAP is proving efficacious, although levels of adherence could improve.

Bronchodilatation induced by deep breaths in relation to transpulmonary pressure and lung volume.

Induced bronchoconstriction in normal subjects can be transiently reversed by a deep breath (airway hysteresis). The mechanisms of airway hysteresis are not fully understood. The aim of these studies was to determine whether the nature of the deep breath (slow or fast inspiration, five or 10 second breath hold) affects the resultant bronchodilatation. Bronchoconstriction was induced in 10 normal subjects by inhalation of histamine until specific airway conductance (sGaw) was halved (mean (SEM) post-histamine sGaw 0.099* (0.009) s-1 cm H2O-1). A subsequent deep breath to total lung capacity (TLC) increased sGaw by 57% (13%) and neither the rate of inspiration to TLC nor periods of breath holding at TLC produced a significantly different degree of bronchodilation. Reducing the volume of the deep breath produced progressively less bronchodilatation and this was no longer significant after a breath to 68% (2%) TLC. To determine whether the volume of the deep breath or the accompanying increase in transpulmonary pressure (PstL) was responsible for the effect on sGaw, subjects were studied with an oesophageal balloon in place with and without their chest strapped. Subjects took a deep breath to a PstL of 20 cm H2O after bronchoconstriction had been induced by histamine. The degree of bronchodilatation (mean (SEM) %) was not significantly different (strap on 25 (6), strap off 36 (5)) even though significantly larger lung volumes (as % TLC) were reached with the strap off (strap on 57 (2), strap off 78 (3)). These results suggest that PstL rather than lung volume during a deep breath determines airway hysteresis.

Sweet's syndrome associated with sideroblastic anaemia.

Previous reports have noted an association between Sweet's syndrome (acute febrile neutrophilic dermatosis) and leukaemia, and less commonly other haematological abnormalities. We report a previously unrecognised association between Sweet's syndrome (SS) and sideroblastic anaemia (myelodysplastic syndrome--refractory anaemia with ring sideroblasts). Both patients were males and one had prominent extracutaneous features of SS. Bone marrow cytogenetic studies were normal in this latter patient and neither patient showed progression to leukaemia.

Effects of continuous positive airway pressure breathing on lung volume and distensibility.

In this study the effects on lung elastic behavior of 10 min of breathing at a continuous positive airway pressure (CPAP) of 10 cmH2O were examined in 10 normal subjects. To investigate whether any changes were induced by release of prostaglandins, the subjects were also pretreated with the cyclooxygenase inhibitor indomethacin. CPAP produced a significant (P less than 0.001) upward shift of the pressure-volume (PV) curve [change in total lung capacity (delta TLC) 374 +/- 67 (SE) ml, mean delta volume at a transpulmonary pressure of 15 cmH2O (delta VL15) 279 +/- 31 ml] with no change in K, an index of lung distensibility. After CPAP the PV curves returned to normal base line within 20 min. The same pattern was observed after indomethacin, but the increase in TLC was significantly less (P less than 0.01) (mean delta TLC 206 +/- 42 ml) mainly because of a slight and not statistically significant increase in base-line TLC. In five subjects further PV curves with and without CPAP were obtained greater than or equal to 7 days after indomethacin. The responses were not significantly different from those obtained before indomethacin (mean delta TLC 366 +/- 89, mean delta VL15 296 +/- 42 ml). We conclude that CPAP produces an upward shift of the PV curve without a change in lung distensibility. In addition, there may be a small degree of resting alveolar duct tone that is influenced by indomethacin.

The effect of histamine challenge on platelet count and platelet activation.

There is conflicting evidence of platelet involvement in asthmatic bronchoconstriction. We sought direct evidence of platelet activation and indirect evidence of platelet sequestration following histamine challenge (HC) in 14 asthmatics and seven non asthmatic control subjects. Peripheral platelet counts and levels of beta thromboglobulin (BTG) were measured immediately before and following HC in the 21 subjects. There were no significant differences in the platelet counts or BTG levels, before or after HC, within or between the two groups. These results do not support platelet activation or accumulation in the lungs occurring immediately following histamine induced bronchoconstriction in asthmatics.

Aspiration biopsy of palpable lymph nodes and the diagnosis of lung carcinoma.

Over a six-year period at this institution aspiration biopsy of palpable lymph nodes has been used in the diagnosis and follow-up of 40 primary lung cancers. Small cell carcinoma was the commonest cell type. In the majority of the patients this was the initial diagnosis of lung cancer, however, there were patients with recurrence after chemotherapy and after surgical management. Diagnosis and classification of tumour using this simple, rapid and safe procedure negates the need for more invasive and costly investigations.

Successful percutaneous balloon occlusion of a large pulmonary arteriovenous malformation.

Percutaneous embolotherapy was carried out successfully in a 79 year old woman with a 56% shunt through a single pulmonary arteriovenous malformation.

Successful pregnancy in a renal transplant recipient taking cyclosporin A.

A 27 year old woman with a fourth cadaveric renal transplant successfully completed a 33 week pregnancy whilst taking cyclosporin A and prednisolone. Her renal function remained stable despite recurrent urinary tract infections, hypertension, gestational diabetes, and Clostridium difficile associated diarrhea. The infant, delivered electively at 33 weeks, was small for gestational age but otherwise normal.