Prevention of cross infection during outpatient spirometry

Risk of bacterial cross infection associated with inspiration through flow-based spirometers

BACKGROUND

Bacterial contamination of spirometers has been documented in water-sealed devices, mouthpieces, and connection tubes. Little information is available about bacterial contamination of flow-based apparatuses such as turbine-type spirometers and pneumotachographs. Inspiration through contaminated equipment is a potential source of cross infection. To investigate bacteria mobilization (ie, bacteria detachment and aerosolization from the instrument) during routine spirometric testing, 2 types of flow-based spirometers were used. Bacteria mobilization during artificial inspiration through in-line filters or cardboard mouthpieces was evaluated.

METHODS

Nine hundred workers undergoing periodic spirometric testing were enrolled at the occupational physician office in 30 sessions of 30 subjects each. The participants were asked to perform a forced vital capacity test in a turbine-type spirometer and in an unheated pneumotachograph fitted with disposable in-line filters or cardboard mouthpieces. To evaluate bacterial mobilization, an artificial inspiration was performed and bacterial growth determined. The bacterial growth analysis was assessed after the first and the thirtieth spirometric tests of each session without disinfecting the instruments between tests. In addition, instrument bacterial contamination was evaluated.

RESULTS

No significant bacterial mobilization and instrument contamination were found in spirometric tests executed with in-line filters. Conversely, a significant bacterial mobilization and instrument contamination were observed in tests performed with cardboard mouthpieces. Differences between the 2 spirometers were not significant.

CONCLUSION

In-line filters may effectively reduce the risk of bacterial cross infection. Inspiration through flow-based spirometers fitted with disposable cardboard mouthpieces is completely safe when combined with spirometer disinfection/sterilization between subjects.

Estudio de la función pulmonar en el paciente colaborador. Parte I

Assessment of respiratory function is the principal tool in the study of patients with lung diseases, allowing physiopathological alterations to be detected, and the severity of the process, its clinical course, and treatment response to be identified. Nowadays, assessment of respiratory function is among the investigations used by Spanish pediatricians. The Techniques Group of the Spanish Society of Pediatric Pneumology undertook the design of a protocol for the study of pulmonary function in children that would incorporate the most recent published consensus documents on basic pulmonary function assessment (spirometry and bronchodilator reversibility testing) and on airway hyperreactivity evaluation using nonspecific provocation tests. The aim of this protocol is to provide a guide to good clinical practice until new changes, based on scientific evidence, are produced.

Infection control of lung function equipment: a practical approach

The degree of risk of cross-infection of patients via lung function testing equipment has yet to be quantified. Based on current evidence, elaborate precautions are not justified for the majority of patients attending the laboratory, but attention to appropriate routine cleaning and disinfection protocols is important. Disinfection and sterilization can be achieved by a variety of methods, although chemical methods should be used with caution. Identification of factors increasing the susceptibility or infectivity of particular patients is important in determining appropriate precautions. Where patients are known to be infectious or are immunocompromized, additional precautions such as using a barrier filter may be appropriate. However, because of cost constraints, the routine use of barrier filters is difficult to justify based on current evidence of minimal cross-infection associated with lung function equipment. Until further studies have been conducted to quantify the degree of risk of cross-infection that lung function test equipment poses, the recommendations given in this review provide a practical approach to dealing with this problem.

Decisions facing the cystic fibrosis clinician at first isolation of Pseudomonas aeruginosa

Chronic endobronchial infection with shape Pseudomonas aeruginosa in patients with cystic fibrosis is associated with more serious disease and reduced survival. Methods for reducing or preventing chronic infection with P. aeruginosa involve rigorous infection control measures and avoidance of cross-infection, which may include segregation of clinics according to microbiological status. The strains of shape P. aeruginosa first isolated from the lungs of cystic fibrosis patients are generally of a non-mucoid phenotype and sensitive to antibiotic therapy. There is some evidence that early aggressive antibiotic treatment may delay chronic infection, improve lung function and improve survival. Further research is needed into the accurate diagnosis of early infection with shape P. aeruginosa, which is often intermittent. In addition, the optimal treatment of patients at first isolation and early colonisation needs to be researched, including choice of antibiotic(s) and route, dosage and duration of antibiotic therapy.