CI: Monitoring Criteria: Patient Positioning (2006)

Orozco-Levi M, Torres A, Ferrer M, et al. Semirecumbent position protects from pulmonary aspiration but not completely from gastroesophageal reflux in mechanically ventilated patients. Am J Respir Crit Care Med. 1995; 152:1387-1390. PubMed ID: 7551400
Study Design:
Randomized Controlled Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To evaluate the effect of 2 body positions (supine vs semirecumbency) on the dynamics of gastroesophageal reflux (GER) in 15 patients with mechanical ventilation and nasogastric tubes.

Inclusion Criteria:
Exclusion Criteria:
Description of Study Protocol:
  • Orotracheal intubation for mechanical ventilation
  • Withhold nutrition and medications via NGT for 12 h before study begins
  • Hold sedating and paralyzing meds
  • Antibiotics given for pneumonia, other respiratory infections, sepsis and preoperative prophylaxis
  • Study each patient at supine and 45° semirecumbent position in random order 48 hrs apart with goal body position attained and continued 12 hr prior to study
  • Baseline gastric, esophageal, bronchial, and blood samples
  • Instill 37 megabecquerels of Tc99 sulfur colloid via NGT
  • Sample gastric, pharyngeal, bronchial, and blood every hour for 5 hours
  • Count radioisotope content of samples by scintigraphy, corrected for decay and express as log10 of cpm
  • Assay gastric, pharyngeal, and bronchial samples for microbiological cultures at baseline and 48 hr
Data Collection Summary:
  • Endotracheal tube pressures
  • Scintigraphic data
  • Microbiological data
Description of Actual Data Sample:

15 patients, 11 men, age 56 +/- 4 years

Summary of Results:
  • Constant endotracheal tube cuff pressures for both positions
  • Scintigraphy
    • Baseline samples not different for any parameter
    • Both body positions ­ pharyngeal radioactivity, p<0.05
    • Radioactivity in pharynx was lower with semirecumbent from 1-4 hr (p<0.05), but by 5 hr no difference
    • Regression line slope not different for 2 positions
    • Blood and gastric radioactivity not changed from baseline, either position
    • Bronchial radioactivity signif ­ at 5 hr in supine position only, p<0.05
    • Radioactivity in bronchial secretions ­ in supine vs semirecumbent (p<0.05)
    • Slopes of regression lines for bronchial radioactivity signif different (p<0.05)
  • Microbiological data
    • Colonization from stomach to pharynx was seen in 4 patients at supine and 2 at semirecumbent position  and 2 from pharynx to bronchi, 1 supine, 1 semirecumbent
Author Conclusion:

GER in mechanically ventilated patients with NGT occurs irrespective of body position. Semirecumbent position does not protect completely from GER and subsequently from oropharyngeal colonization from gastric origin.

Funding Source:
University/Hospital: Universtitat de Barcelona (Spain)
Reviewer Comments:

Selection bias not clear, but using patient as own control helps.

No description of patient acuity- would Spanish ICU patients in 1995 correspond to US ICU patients today?.

Blinding to position not possible, but randomized crossover of same patients

Detailed description of procedures

Reliable outcomes.

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) 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? N/A
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? N/A
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? N/A
  1.3. Were the target population and setting specified? N/A
2. Was the selection of study subjects/patients free from bias? Yes
  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? N/A
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? N/A
  2.4. Were the subjects/patients a representative sample of the relevant population? N/A
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) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? 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? N/A
  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.) 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? No
  4.1. Were follow-up methods described and the same for all groups? N/A
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  4.4. Were reasons for withdrawals similar across groups? 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? No
  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
  5.3. 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
  5.5. 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? Yes
  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? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? 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? 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
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? N/A
  7.2. Were nutrition measures appropriate to question and outcomes of concern? 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? N/A
  7.5. Was the measurement of effect at an appropriate level of precision? N/A
  7.6. Were other factors accounted for (measured) that could affect outcomes? N/A
  7.7. Were the measurements conducted consistently across groups? N/A
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? N/A
  8.2. Were correct statistical tests used and assumptions of test not violated? N/A
  8.3. Were statistics reported with levels of significance and/or confidence intervals? 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)? N/A
  8.6. Was clinical significance as well as statistical significance reported? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? N/A
  10.2. Was the study free from apparent conflict of interest? N/A