Harry Teichtahl

The incidence of respiratory tract infection in adults requiring hospitalization for asthma

Acute respiratory tract infections (RTI) are known to worsen asthma particularly in children. There are few studies in adults assessing the incidence of RTI in patients hospitalized with acute asthma. Aim To document the incidence of RTI in adults hospitalized with acute asthma. Methods A prospective study of patients with acute asthma admitted to the Department of Respiratory Medicine, Western Hospital Footscray, over a 12-month period. A control group was studied from elective surgical inpatients. Patients were investigated with serologic tests for Chlamydia, Mycoplasma, Legionella, and influenza A and R. Nasopharyngeal aspirate (NPA) samples were cultured for influenza, respiratory syncytial virus (RSV), adenovirus, parainfluenza, rhinovirus, and herpes simplex virus. If sputum was available, it was assessed with microscopy and culture. Rlood cultures were taken if patients were febrile and all patients had a chest radiograph. Control subjects completed serologic tests and NPA. Results Seventy-nine patients (33 male and 46 female) and 54 control subjects (26 male and 28 female) were studied. Two patients were enrolled twice. Mean (±SD) age of patients was 35 ±15 years (range, 16 to 66 years), and mean age of control subjects was 37±15 years (range, 18 to 69 years). In the patient group, 29 (37%) had evidence of recent RTI of which 23 were viral. Five of the control subjects (9%) had evidence of recent RTI (p<0.001). Twenty-four patients were positive on serologic and/or NPA culture. Five patients had positive serologic test results and/or NPA culture to two or more agents. Two patients tested positive on sputum, radiograph, and temperature criteria. Three patients tested positive on the basis of radiographic evidence of consolidation, blood neutrophilia, and temperature. Influenza A (13) and rhinovirus (9) were the most common infectious agents. Other agents identified were RSV (one), influenza R (two), adenovirus (one), and Mycoplasma (one). Influenza and rhinovirus infections occurred predominantly in late and early winter, respectively. Summer hospitalization did not relate to RTI. Conclusion Thirty-seven percent of adult patients with acute asthma admitted to the Department of Respiratory Medicine over a 12-month period had evidence of recent RTI.

Sleep-disordered breathing with chronic opioid use

Chronic opioid use for pain relief or as substitution therapy for illicit drug abuse is prevalent in our societies. In the US, retail distribution of methadone and oxycodone has increased by 824 and 660%, respectively, between 1997 and 2003. μ-Opioids depress respiration and deaths related to illicit and non illicit chronic opioid use are not uncommon. Since 2001 there has been an emerging literature that suggests that chronic opioid use is related to central sleep apnoea of both periodic and non-periodic breathing types, and occurs in ∼ 30% of these subjects. The clinical significance of these sleep-related abnormalities are unknown. This review addresses the present knowledge of control of ventilation mechanisms during wakefulness and sleep, the effects of opioids on ventilatory control mechanisms, the sleep-disordered breathing found with chronic opioid use and a discussion regarding the future research directions in this area.

Scoring polysomnography respiratory events: the utility of nasal pressure and oro-nasal thermal sensor recordings

OBJECTIVE To evaluate the clinical utility of nasal cannula/pressure (NP) and oro-nasal thermal sensor (Th) recordings, alone and in combination for scoring respiratory events during routine diagnostic polysomnography (PSG). BACKGROUND The use of Th devices to measure airflow during PSG is not recommended because Th are insensitive to airflow changes other then complete airflow cessation. It has been suggested that NP recording is a better measure of airflow and can also detect increased upper airway resistance during PSG. METHODS Thirty consecutive PSGs were examined using 13 standard channels including Th and NP recordings. Respiratory events were scored separately utilizing NP+Th, Th alone and NP alone in a blinded fashion using modified AASM criteria. Respiratory events were time matched to within 5 s for each of the recording methods. RESULTS NP+Th detected more events than Th alone (P<0.0001); NP+Th detected more events than NP alone (P<0.0001) and NP alone detected more events than Th alone (P<0.0001). For AHI >50, NP alone and Th alone each detected 90% of matched NP+Th events. However, for AHI <50, NP alone detects 54% and Th alone detects 42% (P<0.005) of matched NP+Th events. For AHI >50, NP alone scored 97% of matched Th alone scored respiratory events, and Th alone scored 94% of NP alone scored respiratory events (P>0.05). However, for AHI<50, NP alone scored 90% of matched Th alone scored respiratory events, whereas Th alone scored 62% of matched NP alone scored events (P<0.0001). CONCLUSIONS In severe sleep disordered breathing (AHI >50), NP+Th, NP alone and Th alone have similar ability to detect respiratory events. When AHI <50, NP+Th appears better for detecting respiratory events than NP or Th alone. If only one measure of airflow is used, NP detects more events than Th.

Structural heterogeneity of the axonemes of respiratory cilia and sperm flagella in normal men.

The ultrastructure of normal human cilia and flagella was examined and quantitatively assessed to determine the normal variations in the structure of the axoneme. Ciliated respiratory epithelial cells and spermatozoa from 10 normal, nonsmoking male volunteers who had normal semen parameters were fixed for electron microscopy. Tannic acid and MgSO4 were included during fixation to enhance, in particular, axonemal components. In 75 axonemal cross sections per sample, the number of outer doublet and central singlet microtubules, outer and inner dynein arms, and radial spokes were recorded. Statistical analysis of the results showed a marked reduction, from the expected value of nine, in the numbers of inner dynein arms (mean +/- SE, cilia, 5.31 +/- 0.13; sperm, 5.38 +/- 0.16) and radial spokes (cilia, 4.95 +/- 0.22; sperm, 5.80 +/- 0.19). The ideal axoneme with all its structural components was seen in only 0.13% of cilia and 0.80% of sperm tails. Significantly more doublet microtubules (P less than 0.05) and less central microtubules (P less than 0.01) and radial spokes (P less than 0.01) were seen in cilia than in sperm tail axonemes. Between subjects there was little variation in the mean number of a structure seen per axoneme. However, within each sample, the variation was considerably higher, particularly for the inner and outer dynein arms and radial spokes. The doublet microtubules had significantly greater standard deviations in the sperm tails compared with the cilia (P less than 0.01), and furthermore, a significantly greater number of sperm tails compared with cilia showed the incorrect number of doublet microtubules (P less than 0.02). In one semen sample, with normal semen analysis, 20% of the sperm tails showed incorrect numbers of doublet microtubules, ranging from 12 + 2 to 5 + 2 compared with only 1.3% in cilia from this subject. This study has demonstrated that the ideal axoneme is rarely seen even in normal samples, probably because of the technical difficulties in resolution and visualization, and stresses the need for thorough documentation of axonemal ultrastructure. This work provides a normal data base for comparison with patients who have chronic respiratory disease and suspected infertility.

Cardiorespiratory function in stable methadone maintenance treatment (MMT) patients.

Patients in methadone maintenance programmes (MMT) often smoke tobacco and cannabis and many have ongoing illicit drug use. There is therefore potential for these patients to have abnormal cardiorespiratory function; however, few studies address this in stable MMT patients. We assessed resting cardiorespiratory function on 50 stable MMT patients (25 males, 25 females). Forty‐six MMT patients were current tobacco smokers, 19 were current cannabis users and none were currently using opioids other than prescribed methadone. We defined abnormalities of respiratory function as those results outside the 95% confidence interval of reference values for normal subjects adjusted for age, weight, height and sex. Thirty‐one (62%) MMT patients had reduced carbon monoxide transfer factor (D L CO); 17 (34%) had elevated single breath alveolar volume (V A) and 43 (86%) had a reduced D L CO/V A ratio. Six patients (12%) had reduced FEV 1; one (2%) had reduced FVC; and nine (18%) had an obstructive ventilatory defect. Ten (20%) patients had PaCO 2 higher than 45 mmHg and 14 (28%) had alveolar to arterial oxygen gradient (A‐aPO 2) higher than 15 mmHg. CXR, Echocardiography and ECG showed no significant abnormalities. We conclude that stable MMT patients have abnormalities of resting respiratory function which may be due to ongoing tobacco cigarette and current or past cannabis smoking.

YOUNG'S SYNDROME (OBSTRUCTIVE AZOOSPERMIA AND CHRONIC SINOBRONCHIAL INFECTION) : A QUANTITATIVE STUDY OF AXONEMAL ULTRASTRUCTURE AND FUNCTION

The ultrastructure and function of nasal cilia and sperm tails were examined in 23 men with Youngs syndrome and compared with data previously collected from 10 normal subjects. Quantitative electron microscopic assessment showed that sperm tails from patients with Youngs syndrome contained significantly fewer central pair microtubules, radial spokes, and inner dynein arms, and their cilia contained less inner dynein arms than normal subjects. The Youngs syndrome patients had normal in vitro ciliary beat frequency (11.4 +/- 0.9 Hz), and 12 of the 23 had normal nasal mucociliary clearance (15.0 +/- 5.0 minutes). However, the remaining 11 had markedly abnormal nasal mucociliary clearance in vivo. In these patients, the deficiency of ciliary inner dynein arms did not appear to affect ciliary function in vitro but may under mucus loading lead to abnormal in vivo ciliary function. The consistent abnormalities shown in cilia and sperm tails, though apparently minor, constitute a common factor in both the reproductive and respiratory tracts which may, in combination with abnormalities in the in vivo environment, lead to the features of Youngs syndrome.