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Hydration

HYD: Assessing Hydration Status (2007)

Citation:
Eaton D, Bannister P, Mulley GP, Connolly MJ. Axillary sweating in clinical assessment of dehydration in ill elderly patients. BMJ 1994 May 14;308(6939):1271. PubMed ID: 8205020
 
Study Design:
Observational study
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Negative NEGATIVE: See Quality Criteria Checklist below.
Research Purpose:
To study the value of axillary (underarm) moisture in assessing hydration in eill elderly patients.
Inclusion Criteria:
People 70 years of age or older consecutively admitted to a hospital with acute but undefined medical conditions.
Exclusion Criteria:

Patients were excluded if they were:

  • terminal
  • had previous intravenous fluids
  • had skin disorders
  • were hypthermic (< 34 degrees C)
  • had bathed in the past 4 hours
  • had used antiperspirants in the past 24 hours
Description of Study Protocol:

Recruitment

100 patients of either gender being admitted to the hospital equal to or over 70 years of age that did not display any of the exclusion criteria

 Design

Pre-weighted tissue paper was applied to the patients' right axilla for 15 minutes (left axilla was used if patient had right hemiparesis). Patient held their arm at their right side.  The paper was then placed into a preweighed plastic bag and reweighed. Two blinded observers graded underarm moisture by feeling the axillae (0=dry, 1=moist). The observer order was random and took place from 1-6 hours after the paper test.

Subjects were classified as dehydrated or not dehydrated according to standards written in a listed reference article written by Goss et al.  These standards included serum:urea creatinine ratios and plasma osmolality. Dehydrated subjects had a serum urea:creatinine ratio (mmol/l:micromol/l) above 1:10 and plasma osmolality above 295mmol/kg.  

Blinding used (if applicable) Not applicable

 Intervention (if applicable) Not applicable 

Statistical Analysis

Statistical analysis not well described.  r values used to compare results obtained between the two axillary wetness graders.  Mean weight gains were compared between the dehydrated and non-dehydrated groups.  Correlations between weight gain and plasma:urine osmolality ratios were calculated again using r-values.

Data Collection Summary:

The plasma specific gravity is an accurate test for identifying volume depletion in the majority of patients.

This study established plasma specific gravity is maintained in a narrow range in young adults and older patients with PSG values >1.0295 should be considered hypovolemic, those with values >1.0280 are probably hypovolemic, and those with values > 1.0265 are possibly hypovolemic

Timing of Measurements

Perspiration measurement tests using the pre-weighted paper were performed within 24 hours of admission to hospital.

However, one of the flaws of the study was that the observation grading of wetness was not performed within a consistent time after using the paper testing. Therefore, those patients who were observed shortly after the paper was applied may have been falsely identified as dry opposed to those who were observed up to six hours after the paper test was applied.

 Dependent Variables

  • Measurement of perspiration in 15 minutes (Weight gain of tissue paper)
  • Observational grading of perspiration (dry or moist)

Independent Variables:  Axillary moisture

Control Variables: Not applicable

Description of Actual Data Sample:

Initial N: 100 patients

Attrition (final N): 64

33 subjects were observed for wetness under their arms by only one observer and were not considered in final data analysis and 3 subjects had paper weight assessment only and also were excluded from final data analysis. 

Age: Mean age 80 years

Gender: 38 men (38%) and 62 women (62%)

Ethnicity: None delineated

Other relevant demographics:

Clinical Indices Reference Standard Outcomes  
Serum urea:cr ratio

mmol/l:micromol/l >1:10 was considered dehydrated status

 

26 subjects defined as dehydated with a mean ratio of 15.5, (range 12.4-19.8)

74 subjects defined as non-dehydrated with a mean ratio of 6.8  (range 6.3-7.5)

 
plasma osmolality

>295mmol/kg was considered dehydrated status

 26 subjects defined as dehydrated with a mean plasma osmolality of 308(range 295-369)

74 subjects defined as non-dehydrated with a mean osmolality of 290 (range of 269-312)**

 

observation wetness

 wet = 1 dry =0

 21 axillae grated dry (24%) by one observer and 24 (32%) by the second observer

 

 

Anthropometrics No differences among subjects were delineated

Location: Barnes Hospital in Cheadle, Cheshire UK

 

Summary of Results:

 

  Dehyrated Non Dehyrated  Total
Dry Axillae    10   12   22
Moist Axillae    10

  54

  64

Total

   20

  66

  86

 Other Findings

Overall, 26% of patients were dehydrated, but among patients without sweating prevalance of dehydration was 45%.

 

Author Conclusion:

Axillary sweating is a reproducible and reliable sign of hydration in ill elderly patients with a high negative predictive value and moderate positive predictive value.

Funding Source:
University/Hospital: Manchester Medical School (UK)
Reviewer Comments:

Study missing adequate description of statistical analysis.

Mistakes found in description of raw data. Examples:

Final N should have been 64, not 66 as indicated in tables.

Study listed the criteria for non dehydration to be a plasma osmolality below 295mmol/kg. However, the statistical range for the non-dehydrated subjects was listed as 269-312.

A major flaw of the study was not using a consistent time between the paper test and the observational test.  The range could have skewed the observational measurements of dryness by a statistically significant degree.

In addition, the biochemical classification of hydration used in this study (urea:creatinine ratio and plasma osmolality may not have been appropriate for the entire population. Patients who were mildly dehydrated may have slipped through and been classified as hydrated.

Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) ???
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) ???
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) ???
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) ???
 
Validity Questions
  1. Was the research question clearly stated? Yes
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
  1.3. Were the target population and setting specified? Yes
  2. Was the selection of study subjects/patients free from bias? No
2. Was the selection of study subjects/patients free from bias? No
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? ???
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? ???
  2.2. Were criteria applied equally to all study groups? No
  2.2. Were criteria applied equally to all study groups? No
  2.3. Were health, demographics, and other characteristics of subjects described? No
  2.3. Were health, demographics, and other characteristics of subjects described? No
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
  3. Were study groups comparable? No
3. Were study groups comparable? No
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? ???
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? ???
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? No
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? No
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) No
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) No
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
  4. Was method of handling withdrawals described? ???
4. Was method of handling withdrawals described? ???
  4.1. Were follow-up methods described and the same for all groups? ???
  4.1. Were follow-up methods described and the same for all groups? ???
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) ???
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) ???
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? No
  4.4. Were reasons for withdrawals similar across groups? ???
  4.4. Were reasons for withdrawals similar across groups? ???
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
  5. Was blinding used to prevent introduction of bias? N/A
5. Was blinding used to prevent introduction of bias? N/A
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
  6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? N/A
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? ???
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? ???
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
  7. Were outcomes clearly defined and the measurements valid and reliable? No
7. Were outcomes clearly defined and the measurements valid and reliable? No
  7.1. Were primary and secondary endpoints described and relevant to the question? ???
  7.1. Were primary and secondary endpoints described and relevant to the question? ???
  7.2. Were nutrition measures appropriate to question and outcomes of concern? ???
  7.2. Were nutrition measures appropriate to question and outcomes of concern? ???
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? ???
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? ???
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  7.7. Were the measurements conducted consistently across groups? No
  7.7. Were the measurements conducted consistently across groups? No
  8. Was the statistical analysis appropriate for the study design and type of outcome indicators? No
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.2. Were correct statistical tests used and assumptions of test not violated? ???
  8.2. Were correct statistical tests used and assumptions of test not violated? ???
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.6. Was clinical significance as well as statistical significance reported? No
  8.6. Was clinical significance as well as statistical significance reported? No
  8.7. If negative findings, was a power calculation reported to address type 2 error? No
  8.7. If negative findings, was a power calculation reported to address type 2 error? No
  9. Are conclusions supported by results with biases and limitations taken into consideration? ???
9. Are conclusions supported by results with biases and limitations taken into consideration? ???
  9.1. Is there a discussion of findings? ???
  9.1. Is there a discussion of findings? ???
  9.2. Are biases and study limitations identified and discussed? No
  9.2. Are biases and study limitations identified and discussed? No
  10. Is bias due to study's funding or sponsorship unlikely? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? No
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? Yes
  10.2. Was the study free from apparent conflict of interest? Yes