Intrarater Reliability of Chest Expansion using Cloth Tape Measure Technique

Objective: The Objective of this study was to determine the intrarater reliability of chest expansion at three different anatomical landmarks using a cloth tape measure among healthy peoples. Materials and Methods: 120 healthy male and female volunteers were evaluated on two occasions in different days. The measures consisted of chest expansion measurement at axilla, fourth intercostals and xiphoid levels. The measurements were taken in the standing position with the arms hanging sideways at all the three different anatomical landmarks. The test-retest reliability of the measurements was determined by intraclass correlation coefficient (ICC) and standard error of measurements (SEMs). Results: An acceptable reliability was determined by ICC values greater than than 0.85 and SEMs less than 5%. The mean age of the subjects was 21.93 years. ICC of all measures ranged between 0.95 to 0.97 and SEMs were 1.9%, 1.8%, 1.5% at the axillary, fourth intercostals and xiphoid level respectively. Conclusions: The findings of this study suggested that, the cloth tape measurement was reliable at all the three different anatomical landmarks of the chest wall. Therefore, this measurement technique could be used as an outcome measure for chest expansion in the management of cardiorespiratory conditions.


Introduction
Breathing is a physiological process that includes inspiration and expiration 1 .Neurological 2 , neuromusclular 3 , cardiorespiratory 4 and other illnesses affects and alters breathing.When lungs expands and contracts it influences the mobility of the chest through the diaphragm and intercostals muscle attachments 5 .A change in the chest excursion because of restricted chest wall mobility has an impact on lung volumes and capacities in those conditions 2,3,4 .Such changes were objectively measured with spirometer which is uncommon to be used in the regular clinical practice.Therefore, the clinicians require a simple and inexpensive technique which is easy to learn and apply in their routine clinical prac-tices.Cloth tape measurement (CTM) technique is a common practice employed to measure chest excursion by the health care professionals 6,7 and this has been used over a decade for objective measurement in various clinical conditions 6,7,8  .A reliability study by Bockenhauer, Chen, Julliard & Weedon, 2007 carried out on six healthy subjects showed intraclass coefficients (ICC) for upper and lower thoracic excursion ranged from 0.81 to 0.91 at upper thoracic and lower thoracic excursion measurements.ICCs were 0.99 and greater when inhalation and exhalation were considered separately 12 .Similarly, an intrarater reliability study carried on twenty-two subjects with ankylosing spondylitis and twenty five healthy subjects at the xiphoid showed ICCs was good (0.85 to 0.97) across the occasions 13 .The findings of the previous studies suggest that the reliability testing on CTM are performed on different populations and with small number of subjects.It indicates that a separate study on the reliability procedures on CTM will be beneficial for standardization of clinical practice.
The common landmarks proposed to measure chest wall mobility in the literature were in the xiphoid process, fourth intercostals, axillary, upper and lower thoracic levels to decide upper, middle and lower thoracic wall mobility respectively.Selecting these sites take over an advantage of representing different lobes' elasticity in the lungs.For instance, the axilla marks the upper lobe, the fourth intercostal space marks the right middle and left lingular lobe (Scot Irwin & Stephen Tecklin, 2004), while the xiphoid level notes both the lower lobes.The estimate technique proposed to measure chest excursion was by holding the tape measure horizontally at the xiphoid level by using a grid as a guide in two different arm position such as hands on head and arms at side 14 .Another way, recommended to measure upper thoracic excursion was assessed by placing the tape measure at the fifth thoracic spinous process and the third intercostals space at the midclavicular line 12 .Similarly, the tape measure was placed at the 10th thoracic spinous process and at the tip of the xiphoid process for the lower thoracic excursion with hand crossed technique for holding the tape 12 .
Anatomic markers marked the reference points for tape placements 12 .
Despite the advantage and the significance of using these landmarks to measure chest excursion, all these sites were not collectively measured in the routine clinical practice.This could be because of variations in measurement strategies and the intrarater reliability values possibly confusing graduate students and novice clinicians while learning the measurement techniques 12, 13 .All the related existing studies use small sample size measured at one or two levels by the assessors with more experience or expert clinicians 12,13 .To our knowledge no study is available examining the intrarater reliability of CTM in chest wall excursion at three different sites collectively measured by the graduate students of health care profession while at training.Therefore, this study aims to address issues by researching the intrarater reliability of chest excursion measurement at the axillary, 4 th intercostals and xiphoid levels using a cloth tape with larger samples assessed by the students while at training.

Study design
This study was a test-retest reliability design in determining chest expansion in three different anatomical levels among healthy peoples.Subjects Subjects were recruited from the faculty of health science program which comprised of 120 (60 males and 60 females) healthy people with a mean of 21.93 and standard deviation of 1.733.The criteria for selection used were as follows: being a volunteer, regardless of gender; being between the ages of 18 to 29; and presenting no signs and symptoms of respiratory disease and postural abnormalities.The Institutional ethics committee approved the study, and a written consent was obtained from each individual.

Experimental measurements
A final year student who was at training level measured thoracic circumference at peak inhalation and peak exhalation for each of the subjects on two occasions.To measure the readings in centimeters, the examiner used " Hands-crossed" technique with the help of cloth tape measure 12 .
Initially the study subjects were asked to stand erect with arms at the side.Upper body for the male subjects was naked Haque M, Faruquee MH, Lahiry S, Tasnim S, Yasmin R, Yasmin N, Chaklader MA whereas female subjects wore a bra.A ballpoint pen marked the anatomical landmark such as fourth intercostal space and xiphoid .Examiner held the tape to make sure, the contour of the skin remained unchanged.Measurement of chest expansion was taken on two occasions.The examiner took measurements successively while the subjects held their breath during the inhalation and exhalation.One daytime period secured between the occassions CTM held around the circumference of the chest at one of three levels.For the upper thoracic excursion, the tape measure was placed in the axillary region.
For the midthoracic excursion and lower thoracic excursion, the tape measure was placed at the fourth intercostals and at the xiphoid process level.An average of three trials reading measured on each occasion and an assistant entered all the readings directly into the Microsoft excel data sheet .In order to minimize the errors the system of entering data into the Microsoft excel was adopted.

Data analysis
SPSS version 16.00 statistical packages analyzed the data.SPSS data sheet imported all averaged data from Microsoft excel spreadsheet.The test-retest variability was determined by an Intraclass correlation coefficient (ICC), Standard error of the mean (SEM) and through the standard error of measurement (SEMs) for all three levels of anatomical landmarks selected.The statistical significance was set at P < 0.05.SPSS statistical package earned the results of the ICC, and the calculation of SEMs values were gained from (Khamwong, Nosaka, Pirunsan, Paungmali, 2010) in order to know the precision of the measurement .The ICC values of 0.80-0.89,and greater than 0.90 were considered as good and high in reliability and SEMs value of less than 5 % is considered as reliable 16 .

Results
Table I, shows the mean, standard deviation, SEM and SEMs for all measures.SEMs of all the anatomical landmarks were reliable as the values are less than 5 %.Intraclass correlation coefficient (ICC) a two-way mixed model employed for intrarater reliability.

Discussion
This study used ICC, SEMs to assess the reliability of chest wall expansion at three anatomical levels of the chest in an attempt to use the measures to examine the effectiveness of an intervention in both clinical and research settings such as investigating the effect of chest and manual therapy intervention on the chest wall.The results showed that all the three levels of measurement were reliable (Table I 12,13 .The ICC for the present study across the occasions was 0.93 to 0.97 compared with (ICC = 0.81 to 0.84) (Bockenhauer et   al., 2007) and (ICC = 0.85 to 0.97) 13 .However, these ICCs were obtained on xiphoid level and an upper and lower thoracic measurement.Therefore, the .However, direct agreement with the results of the present study was not possible because of the population, as all the studies are carried out on ankylosing spondylitis.But then this study was succeeded on young healthy population.
In the current study, the intrarater reliability measurement, were made with large number of samples with equal contribution of the genders, when compared to the earlier studies 12,13  .But the present study used axillary, intercostals, tenth rib as the landmark to measure thoracic exursion as it will give upper, middle and lower thoracic expansion measurement.So, the authors recommend that these three anatomical landmarks utilized in the present study could be used by novice clinicians.
Literatures employed sitting and standing position for measuring chest expansion 11,13 .In order to simplify handling the measuring tape easier, standing position was preferred in this study.This posture allowed the positioning and the use of the tape measures alternatively and without the need to mobilize the subject during the collection, reducing the use of technical errors.Since the posture adopted was the same for all the three measurement landmarks, we can rule out the possibility that posture influenced the results.

Conclusions
The intrarater reliability proved to be high, with the highest reliability occurring with the xiphoid landmark when compared to fourth intercostals and axillary level.The high reliability found in the present study can be credited to anatomical landmarks selected with large sample size.Using the mean of three trials for data analysis may also have caused high reliability results.Further work, is underway to find out the interrater reliability using cloth tape measures with these sets of samples among novice clinicians.