Peak Flow Meters

From Mike:
Another good reason to handle your asthma without medication.

Dr Toru Oga and colleagues at Kyoto University note that although recent international guidelines suggest the use of individual best PEF rather than predicted PEF in asthma management, "there is little evidence to support which index is more appropriate."

In the February issue of the Journal of Asthma, the researchers report that they studied 166 asthmatics, all of whom had been treated for more than 6 months.

Subjects used one of 3 types of peak flow meter to record their PEF at home four times daily over a period of weeks. Best PEF was then established by determining "maximal PEF achieved at any time from all previous measurements." Predicted PEF was calculated based on a study of standard PEF in almost 2800 healthy Japanese subjects.

There was a "strong" correlation between best and predicted PEF, but mean best PEF was significantly higher than mean predicted PEF. In 76 patients (46%), best PEF was more than 50 L/min higher than predicted PEF. In 22 patients, (13%) it was more than 50 L/min lower.

Given these findings, the researchers point out that when predicted PEF is used, in over half of patients "there may be overestimation or underestimation of medication used for asthma management." They therefore conclude that "best PEF may be the better index for the management of patients with asthma." J Asthma 2001;38:33-40

COPD PEF BETTER MORTALITY PREDICTOR IN COPD THAN ASTHMA

Best peak expiratory flow (PEF) appears to be a better predictor of overall mortality in patients with chronic obstructive pulmonary disease (COPD) than in those with asthma, Danish researchers report in the March issue of the American Journal of Respiratory and Critical Care Medicine.

From Mike:
This is another reason why I keep harping on why it is so important to address asthma mechanically along with or instead of with drugs and steroids.

On the other side of the coin, it is important to know that PEAK FLOW METERS can be a useful adjunct if they are NOT OVER-USED.

Study Director Dr. Anne L. Fuhlbrigge, of Brigham and Women's Hospital in Boston, told Reuters Health that the new findings support the routine use of FEV1 in asthmatic patients, as is already recommended by the National Asthma Education and Prevention Program.

The investigators examined the usefulness of FEV1 for predicting asthma attacks in nearly 14,000 children who were enrolled in a 15-year longitudinal study of lung function. Routine FEV1 measures were correlated with the occurrence of asthma attacks in the year following each measurement.

As FEV1 increased, the risk of having an asthma attack decreased, the team writes. The percent predicted FEV1 (FEV1%) was an independent predictor of subsequent asthma attacks, as reported by parents, with odds ratios of 2.1 and 1.4 for patients with an FEV1% below 60% or between 60% and 80%, compared with children with an FEV1 measurement above 80%, respectively. Using children's self reports to identify asthma attacks, these odds ratios were 5.3 and 1.4, respectively.

Dr. Fuhlbrigge noted that FEV1% "seems to define different levels of risk."

In the journal, the authors point out that measurement of FEV1 has several advantages. In particular, "improvements in FEV1 parallel improvements in other asthma outcomes, such as exacerbations, healthcare utilization, symptoms, health-related quality of life, and rescue medication use." Also, the test is easy to perform.

Despite these advantages, survey studies and reviews of medical records indicate that FEV1 is "not being used routinely in the majority of adult or pediatric patients," Dr. Fuhlbrigge told Reuters Health. She hopes that the new study results will help change this.

J Allergy Clin Immunol 2001;107:61-67.

From Mike:
PEAK FLOW METERS can be a useful adjunct if they are NOT OVER-USED.

But what about the number count at the tests page of this Web site? It may be easier, more fun and safer when performed with the insightful guidance of a health professional.

Overend TJ, Anderson CM, Lucy SD, Bhatia C, Jonsson BI, Timmermans C.

School of Physical Therapy, University of Western Ontario, London, Ontario, Canada. toverend@uwo.ca

OBJECTIVE: To systematically review the evidence examining the use of incentive spirometry (IS) for the prevention of postoperative pulmonary complications (PPCs).

METHODS: We searched MEDLINE, CINAHL, HealthSTAR, and Current Contents databases from their inception until June 2000. Key terms included "incentive spirometry," "breathing exercises," "chest physical therapy," and "pulmonary complications." Articles were limited to human studies in English. A secondary search of the reference lists of all identified articles also was conducted. A critical appraisal form was developed to extract and assess information. Each study was reviewed independently by one of three pairs of group members. The pair then met to reach consensus before presenting the report to the entire review group for final agreement.

RESULTS: The search yielded 85 articles. Studies dealing with the use of IS for preventing PPCs (n = 46) were accepted for systematic review. In 35 of these studies, we were unable to accept the stated conclusions due to flaws in methodology. Critical appraisal of the 11 remaining studies indicated 10 studies in which there was no positive short-term effect or treatment effect of IS following cardiac or abdominal surgery. The only supportive study reported that IS, deep breathing, and intermittent positive-pressure breathing were equally more effective than no treatment in preventing PPCs following abdominal surgery.

CONCLUSIONS: Presently, the evidence does not support the use of IS for decreasing the incidence of PPCs following cardiac or upper abdominal surgery.