The employer appeals from the compensation judge's award of permanent partial disability to the employee for her work-related asthma.  We affirm.

The employee, Angie S. Taylor, began working for the City of Fridley in its street department in 1996.  In late 2005, Fridley experienced a strong storm that damaged many trees and caused obstructed roadways.  The employee worked for several weeks clearing fallen trees and branches and running them through a chipper machine. In that assignment, she was exposed to considerable wood dust and began to experience watering eyes, running nose, sneezing, exhaustion, headaches, throat mucus, and difficulty breathing.

Ms. Taylor was initially diagnosed by her treating physicians as having allergic rhinitis secondary to exposure to sawdust at work.  Dr. Jeffrey Mandel performed an independent medical examination for the employer and insurer in December 2006 and agreed that the employee's condition was work-related.  The employer accepted primary liability for the employee's condition.

The employee's symptoms improved during the spring and summer of 2006, when she was not assigned to work with the chipper.  However, in the fall of 2006 and into the spring of 2007, Ms. Taylor again worked with the chipper and her symptoms returned.  Her medical providers tried medications, inhalers, and a dust mask to see if the employee could tolerate this work, but none of these approaches were successful.  The employee was terminated by the employer some time in 2007.

In March 2007, Ms. Taylor was referred to a pulmonologist, Dr. Melissa King Biggs, who performed pulmonary testing that indicated mild, intermittent asthma.  In September 2008, when the employee returned to Dr. King Biggs, she reported that her symptoms had continued throughout the spring.  Spirometry showed mild airways obstruction, and Dr. King Biggs diagnosed asthma with persistent symptoms.^[1]  The employee was treated with inhaled corticosteroids, and given a peak flow meter and an albuterol inhaler.

Over the next several years, the employee's symptoms continued to worsen.  By the date of the hearing, May 14, 2013, the employee was having rhinitis symptoms daily.  The employee's asthma attacks had also become more frequent and severe, and involved increased rhinitis and symptoms of constricted breathing.  The triggers for these attacks had increased to include not only wood product dust, but cold temperatures, pollen, dust, smoke, perfume, and other scents.  Ms. Taylor has had to carry a rescue inhaler at all times in case of a severe asthma attack.

The employee has been prescribed a number of medications for her respiratory symptoms.  Her medications have resulted in secondary symptoms including headaches, sinus pain, sleepiness, and fatigue.  Because of the sleepiness, Ms. Taylor needs to nap frequently despite sleeping 12 hours per night.  She must sleep sitting up to avoid choking on mucous.  To deal with her respiratory condition, the employee has had special central air conditioning installed in her home and uses a special vacuum to minimize dust and dander in her house.  Leaving the controlled environment of her home increases the chances of an asthma attack and makes the employee anxious; her anxiety in turn further increases the risk of an asthma attack.

The employee has continued to see Dr. King Biggs for regular follow-up appointments that have regularly included pulmonary function testing.  Over the years, most of the test results show FEV1 measurements ranging from approximately 60 to 102 percent, with interpretations indicating a normal, mild or moderate obstructive pattern. ^[2]

In 2012, Dr. King Biggs was asked to provide a permanency rating for the employee’s asthma.  To rate the condition under the disability schedules, Dr. King Biggs scheduled the employee for methacholine challenge testing on April 4, 2012.  Methacholine challenge testing would require the employee to refrain from the use of inhalers for up to 48 hours prior to testing.

On April 3, 2012, at Dr. King Biggs' office, the employee was tested by spirometry before her scheduled methacholine challenge testing.  The spirometry testing that day gave an FEV1 reading of 39 percent, which Dr. King Biggs described as severe obstruction with marked bronchodilator response.  Because this was below the safety threshold for the administration of methacholine challenge testing, Dr. King Biggs did not perform that test.

In a health care provider report dated April 3, 2012, Dr. King Biggs rated the employee with a 78 percent permanent partial disability, consisting of 75 percent based on an FEV1 measurement less than 40 percent under Minn. R. 5223.0560, Subp. 3.B.(14), and an additional 3 percent pursuant to Subp. 3.C.(1) because of the employee’s need for persistent therapy by inhaled steroids.

On July 10, 2012, Ms. Taylor was reexamined by Dr. Jeffrey Mandel on behalf of the employer and insurer.  Dr. Mandel diagnosed allergic rhinitis and asthma and noted that the employee had developed dyspnea and that her asthma had shown gradual worsening with more triggering and was now moderate in severity.  He was uncertain whether the worsened airflow shown in the employee's April 2012 spirometry testing represented an overall downward trend in lung function or just a temporary worsening.  Dr. Mandel considered the employee’s asthma to be cyclic in nature that could be expected to fluctuate over time.  Dr. Mandel offered restrictions that the employee not work around wood dust, avoid extremes of temperature, and avoid drying or irritating fumes, vapors, and mists.  He concluded that she had not yet reached maximum medical improvement.

On January 8, 2013, after examining further medical records and the employee's deposition, Dr. Mandel wrote a letter to the employer’s attorney to update and further explain his opinions.  He stated that his diagnosis was of allergic asthma and sinusitis, which, by the employee's symptoms, appeared quite limiting despite recent spirometry showing only a mild degree of airway obstruction.  He noted that it was typical in cases of this type of asthma to have a history of exacerbations and remissions, accompanied by wide fluctuations in FEV1 readings.  He opined that the low reading in April 2012 was temporary in nature.  He believed that the employee's condition, though variable, was stable in that she had not needed emergency room treatment or more frequent medical appointments with her pulmonologist, and he stated that “she is likely at or near maximum medical improvement.”  Dr. Mandel reported that it was difficult to assign a permanency rating in the absence of methacholine challenge testing, which he noted had not been done "probably because of her clinical state."  He concluded that he could provide only a range of possible ratings without such testing.  In his view, the employee's permanency might be rated in a range of 10 to 15 percent based on her most recent spirometry.

On May 10, 2013, Dr. King Biggs wrote a letter to the employee’s attorney explaining the rationale for her permanency rating.  She noted that methacholine challenge testing could not be performed safely because of the employee's condition.  As a result, Dr. King Biggs had applied Minn. Rule 5223.0560, subp. 3.B.(14) since that section does not require a methacholine measurement and the FEV1 measurement is less than 40 percent.  Since the employee's April 3, 2012, FEV1 measurement was 39 percent, Dr. Kings Biggs rated permanent disability rating at 75 percent under that rule, adding an additional 3 percent for persistent steroid inhaler treatment as specified under subpart 3.C.(1) of the same rule.

The employee filed a claim petition seeking permanent total disability and permanent partial disability resulting from her 2006 work injury.  The claim petition was heard by Compensation Judge Paul Rieke on February 20 and May 14, 2013.  In his Findings and Order, the compensation judge found the employee to be permanently and totally disabled as of June 1, 2010, and awarded the employee permanent partial disability as rated by Dr. King Biggs.  The employer has appealed the award of permanent partial disability, but has not challenged the finding of permanent total disability.

In its appeal, the employer raises two arguments in opposition to the compensation judge’s determination of permanent partial disability.  The employer contends first that the compensation judge erred in awarding any permanent partial disability because the employee’s medical condition is not stable because of the fluctuations in the results of her pulmonary testing, and the employee has not reached maximum medical improvement.  Second, the employer argues that the permanent partial disability rating accepted by the compensation judge did not comply with the requirements of Minn. R. 5223.0560.

On the first argument, the employer cites to case law that it claims support a proposition that an employee’s condition must have stabilized before permanent partial disability can be ascertained.  However, in those cases there was evidence that the employee might improve with recommended medical care, and, as a result, the extent of the employee’s permanent disability was not known at the time of the hearing.  In one of the cited cases, Vierow v. Southwest & West Cent. Educ. Coop. Serv. Unit, 39 W.C.D. 869 (W.C.C.A. 1986), this court affirmed a compensation judge’s denial of part of the employee’s permanent partial disability claim where the doctor providing the rating had testified that therapy might mitigate the condition.

The evidence in the present case has no similarity to the factors in Vierow.  The hearing took place more than seven years after Ms. Taylor’s injury.  There was no indication in any of the medical records or reports that any improvement in the employee’s asthma could be anticipated.  No treatment recommendations were made other than to try to minimize the effect of the asthma attacks.  Finally, even the IME, Dr. Mandel, stated in his January 2013 report that the employee’s condition was stable and that she was “likely” at maximum medical improvement.  We find no basis in the evidence for a conclusion that that the compensation judge’s award of permanent partial disability benefits was premature.

The second question on the issue here is whether the compensation judge properly applied the permanent partial disability rules in making his determination.  Permanent partial disability for respiratory conditions is rated under Minn. R. 5223.0560.  Subpart 3 of that rule covers “asthma and pulmonary conditions with an asthmatic component.”  Rule 5223.0560, subp. 3.A. provides that ratings are to be based on:  1) Pulmonary function tests; 2) “the level of bronchial responsiveness as measured by standardized methacholine testing;” and 3) the need for bronchodilator therapy.^[3]  The ratings for asthma found in 5223.0560, subp. 3.B. are based on the FEV1 result as a percentage of predicted, the measure of “PD20” from the methacholine challenge test, and whether or not bronchodilator therapy is needed.

In a Health Care Provider Report dated April 3, 2012, the employee’s treating specialist, Dr. King Biggs, rated the employee’s disability under 5223.0560, subp. 3.B.(14), “class XIV: FEV1 or FEV1/FVC is less than 40 percent but greater than 30 percent of predicted, 75 percent.”  Dr. King Biggs explained her rationale for the rating in a subsequent letter to the employee’s attorney.  She stated that she used this subsection in part because the employee’s pulmonary test on April 3, 2012, showed an FEV1 of 39 percent of predicted.  Further, this subsection is the first in the listing of ratings not to require methacholine testing.  Methacholine testing requires a patient to refrain from using an inhaler for 24 to 48 hours.  Dr. King Biggs stated that Ms. Taylor could not safely abstain from the use of her inhaler for that period and that “performing a methacholine challenge test on someone with such low spirometry is dangerous and against the standards of our practice.”

The employer claims the rating by Dr. King Biggs is incorrect.  While the pulmonary testing on April 3, 2012, is in accord with the requirements of subdivision 3.B.(14), as to the FEV1 result, there have been other pulmonary function tests that show a better result.  The compensation judge noted in his memorandum, however, that Dr. King Biggs used the test results closest in time to her report.   Further, the employee credibly testified that her breathing ability is affected by a long list of triggering agents and can fluctuate on a seasonal or even a daily basis depending on her exposure to those agents.  As the compensation judge also noted, there is no provision in the rules for averaging test results nor, we might add, is there any requirement that the best test results must serve as the basis for rating permanent partial disability resulting from asthma.  The question here is whether the rating of permanent partial disability accurately reflects the functional impairment caused by the work injury.  Substantial evidence, including the unappealed finding that the employee is permanently totally disabled, supports the rating accepted by the compensation judge.

The employer also challenges the use of 5223.0560, subp. 3.B.(14) in this case where no methacholine testing was done.  The employer argues that 5223.0560, subp. 3.A.(2) makes methacholine testing an absolute requirement of an award of permanent partial disability, and the absence of such testing means that no permanent partial disability may be awarded to the employee.  We considered this argument in Eisenmenger v. Raven Indus., slip op. (W.C.C.A. Mar. 15, 2000), and in that decision concluded that methacholine testing was not a requirement for all awards of permanent partial disability in cases of asthma.  We noted that while subdivisions 3.B.(1) to (13) contain “PD20” values from methacholine tests that must be met, no PD20 values are set out in either (14) or (15). The employer provides no information as to what PD20 value should be used when the FEV1 result is less than 40 percent of predicted.  More importantly, in Eisenmenger, as in the present one, the medical evidence was that a methacholine challenge test which seeks to trigger airways constriction was unsafe for the employee.

The employer urges us to reverse Eisenmenger, but we decline to do so.  The employer’s argument would mean that no employee with asthma could receive an award of permanent partial disability in the absence of methacholine testing.  Since that test requires that no inhaler be used for 24 to 48 hours, and since those employees with the worst asthma would not be able to refrain from using an inhaler for that period, the result would be that the employees with the most disabling asthma condition would not be compensated for their functional loss.  We conclude the determination of the compensation judge is in accord with the rules and is supported by substantial evidence.

The compensation judge’s decision is affirmed.