AARC Clinical Practice Guidelines: Capillary Blood Gas Sampling for Neonatal and Pediatric Patients.

In the absence of an indwelling arterial catheter, capillary blood gas sampling may be used to evaluate the acid/base and ventilation status of neonatal and pediatric patients with cardiorespiratory conditions. These guidelines were developed from a comprehensive review of the literature to provide guidance for the collection, handling, and interpretation of blood obtained from an arterialized capillary sample. Capillary and venous blood gas measurements are a useful alternative to arterial blood gas measurements for neonatal and pediatric patients who do not require close monitoring of [Formula: see text] In the presence of alterations in body temperature, blood pressure, or peripheral perfusion, agreement between a capillary blood gas with an arterial sample is recommended to determine whether changes in these physiologic conditions reduce reliability. Perfusion to the sample site should be assessed and preference given to blood sampling from a well perfused site, and blood should be analyzed within 15 min of sampling to minimize the propensity for pre-analytical errors. Clinicians should consider re-collecting a blood sample, obtained from an artery, vein, or capillary, when the blood gas or analyte result interpretation does not align with the patient's clinical presentation. A pneumatic tube system can be reliably used to transport blood gas samples collected in a syringe and capillary tube to a clinical laboratory for analysis. To reduce the cumulative pain effect and risk of complications, the capillary puncture procedure should be minimized when possible. Non-pharmacologic interventions should be used to reduce pain associated with capillary blood gas sampling. Automatic lancets are preferred to puncture the skin for capillary blood gas collection.

Kittredge Lecture: Airway Safety in Neonatal and Pediatrics.

During invasive ventilatory support, infants and children are inherently at risk for developing injury or complications related to the insertion and maintenance of an endotracheal tube (ETT). It is essential for respiratory therapists to understand the factors that contribute to the propensity for harm while preparing for, inserting, securing, and maintaining the position of an ETT throughout the duration of use. Implementing care bundles based on the available literature is useful in reducing iatrogenic complications as well as the risk for morbidity and mortality of pediatric patients requiring an ETT to facilitate respiratory support.

Development and internal validation of an equation using anthropometric measures to predict correct endotracheal tube insertion depth.

PURPOSE: To develop, internally validate, and assess the utility of implementing a regression model for determining endotracheal tube (ETT) insertion depth. RESEARCH METHODS: We recorded height, weight, age, sex, ETT internal diameter (ID), lip marking, and tracheal position from the electronic record from a random subset of 2,000 intubated subjects obtained from 1 January 2009 to 5 May 2012. A multivariable linear regression model was constructed and validated by a nonparametric bootstrapping technique using unrestricted random sampling methods. A prospective pilot of subjects admitted to the pediatric intensive care unit requiring invasive mechanical ventilatory support was conducted from 7 January 2019 to 31 May 2019. Those with spinal and/or skeletal malformations, without a post-intubation chest-x-ray (CXR) order, or whose CXR quality impaired visualizing the carina and ETT tip, were excluded. The validated regression equation determined insertion depth. CXR following intubation determined ETT position. Demographic data were summarized. Two-tailed, one-sample binomial test of proportions assessed differences in the proportion of correct position by the equation. MAIN FINDINGS: Four hundred and seventy-seven subjects included in model construction yielded 10,000 independent samples for internal validation; 55% were female, and the mean age (SD) was 47 (63) months. Bias between bootstrap coefficients and refined model estimates were negligible (P < 0.01). Eleven subjects in the pilot were female (64%), mean age (SD) of 36.7 (38) months. Four protocol violations (36.4%) resulted in malposition. Subsequent repositioning per protocol resulted in 100% correct positioning (P = 0.01). CONCLUSION: The regression equation [0.8636 * (Ht. 0.6223)] facilitated correct ETT placement. A larger, diverse sample is required for external model validation.

An evaluation of temperature stability and resistance in neonatal ventilator circuits.

BACKGROUND: Gas conditioning minimizes complications associated with invasive ventilation of neonates. Poorly conditioned gas contributes to humidity deficit, facilitates condensate pools, and contributes to safety events. The specific aim was to objectively quantify the temperature drop across the unheated portion of a neonatal circuit and the impact condensation has to resistance to flow in the ventilator circuit. METHODS: Ventilator circuits and filters were obtained, assembled according to manufacturer recommendations, and operational verification procedures were performed prior to data collection. A neonatal test lung was connected to each Servo-I ventilator with the following settings: pressure control IMV mode; inspiratory pressure: 14 cm H2O to achieve an exhaled tidal volume of 6.0 mL; PEEP: 5 cm H2O; pressure support: 5 cm H2O, FIO2: 0.21; set frequency 40/min; and inspiratory time: 0.4 s. The Fisher and Paykel MR850 and ChonchaTherm Neptune heaters were set at a temperature of 40°C. To evaluate both systems under similar conditions, the ChonchaTherm Neptune heater humidity control was set to midline. Heaters were turned on simultaneously and given 1 h to equilibrate. Readings for room temperature, airway temperature at the patient connection, airway resistance, exhaled tidal volume, and direct observation of circuit condensation and (or) pooling were recorded hourly for a 48-h period. Summary statistics were calculated for the variables of interest. RESULTS: Mean (±SD) air temperature was 26.3°C (±1.4) for the Fisher & Paykel MR850 system and 26.2°C (±1.5), for the ChonchaTherm Neptune system. Mean (±SD) airway resistance was 229.3 cm H2O/L/s (±81.0) for the Fisher & Paykel system and 196.2 cm H2O/L/s (±39.4) for the ChonchaTherm Neptune system. Mean (±SD) tidal volume for the Fisher & Paykel MR850 system was 6.5 mL (±0.4), and for the ChonchaTherm Neptune system was 7.2 mL (±0.6). CONCLUSION: Circuit condensate increased tidal volume delivery and airway resistance. Temperature at the patient connection was lower than the temperature monitored by the system 12 inches distally, which can negatively impact gas conditioning.

AARC Clinical Practice Guideline: Management of Pediatric Patients With Tracheostomy in the Acute Care Setting.

Children requiring a tracheostomy to maintain airway patency or to facilitate long-term mechanical ventilatory support require comprehensive care and committed, trained, direct caregivers to manage their complex needs safely. These guidelines were developed from a comprehensive review of the literature to provide guidance for the selection of the type of tracheostomy tube (cuffed vs uncuffed), use of communication devices, implementation of daily care bundles, timing of first tracheostomy change, type of humidification used (active vs passive), timing of oral feedings, care coordination, and routine cleaning. Cuffed tracheostomy tubes should only be used for positive-pressure ventilation or to prevent aspiration. Manufacturer guidelines should be followed for cuff management and tracheostomy tube hygiene. Daily care bundles, skin care, and the use of moisture-wicking materials reduce device-associated complications. Tracheostomy tubes may be safely changed at postoperative day 3, and they should be changed with some regularity (at a minimum of every 1-2 weeks) as well as on an as-needed basis, such as when an obstruction within the lumen occurs. Care coordination can reduce length of hospital and ICU stay. Published evidence is insufficient to support recommendations for a specific device to humidify the inspired gas, the use of a communication device, or timing for the initiation of feedings.

Devices Used for CPAP Delivery.

CPAP is a spontaneous mode of ventilation that maintains a constant airway pressure during the inspiratory and expiratory phases. This therapeutic modality is used across the continuum of care from pre-hospital treatment to intensive and acute care units to the home care environment to treat a host of acute and chronic clinical conditions. A variety of devices are currently available for the delivery of CPAP, including oxygen-conserving valved systems, continuous-flow generators, portable demand-flow devices, and mechanical ventilators. The devices used to administer CPAP vary in complexity, performance, monitoring capabilities, ability to provide humidification, and safety features. Regardless of the type of device or system used to deliver CPAP, a system that is unable to meet or exceed the patient's flow demands has the propensity to deliver pressure and oxygen concentrations that are lower than intended or set. If undetected, this can contribute to adverse patient outcomes. Considerations for device selection depend on the setting (eg, pre-hospital, acute care, critical care, home care), length of therapy (ie, short vs long-term), patient safety (eg, alarms, monitoring devices), and comfort. Understanding the science and clinical application of CPAP delivery systems can assist clinicians in a variety of care settings with selecting the type of device that best matches the clinical setting, and thus with optimizing therapeutic effectiveness by maximizing patient comfort, safety and stability of pressure, and FIO2 delivery.

Accuracy and Precision of an Optoacoustic Prototype in Determining Endotracheal Tube Position in Children.

BACKGROUND: Confirmation of endotracheal tube (ETT) tip position and timely identification and correction of malposition is an essential component of care for endotracheally intubated and mechanically ventilated children. We evaluated the ability of a prototype optoacoustic medical device to determine ETT tip position. We hypothesized that the precision of optoacoustic assessment of ETT tip position would be comparable to chest radiography. METHODS: We recruited children aged newborn to 16 y who were admitted to the pediatric ICU requiring tracheal intubation and undergoing a chest radiograph for clinical purposes. After positioning each child on a chest radiograph plate, a sterile optical fiber, temporarily inserted through the ETT, emitted laser pulses perpendicular to the fiber and to the ETT, generating acoustic (ultrasound) waves in overlying tissue when the tip of the fiber passed beneath an acoustic sensor in the sternal notch. The distance from the ETT tip to the peak acoustic signal was used to calculate the distance from the ETT tip to the carina, which was compared with the same distance calculated by the radiologist reading the chest radiograph. Pearson's correlation coefficient, paired t tests, a Bland-Altman plot were used to compare the measures (P < .05 was considered statistically significant). RESULTS: Twenty-six subjects were enrolled: 15 (57.7%) were male, median (interquartile range) age, weight, and height were 9 months (4-24), 9.6 kg (5.7-13.0), and 75 cm (62-90), respectively. All ETTs were cuffed (internal diameter range 3.0-5.0 mm). The relationship between optoacoustic and chest radiograph measurements was strong (r = 0.91, P < .001). Bias was 0.1 cm with narrow limits of agreement between measures (0.58 cm and 0.76 cm). CONCLUSIONS: The optoacoustic prototype accurately determined ETT tip position and was comparable in precision to chest radiograph.

Adherence to Endotracheal Tube Depth Guidelines and Incidence of Malposition in Infants and Children.

BACKGROUND: Adherence to guidelines for endotracheal tube (ETT) insertion depth may not be sufficient to prevent malposition or harm to the patient. To obtain an estimate of ETT malpositioning, we evaluated initial postintubation chest radiographs and hypothesized that many ETTs in multiple intubation settings would be malpositioned despite adherence to Pediatric Advanced Life Support and Neonatal Resuscitation Program guidelines. METHODS: In a random subset (randomization table) of 2,000 initial chest radiographs obtained from January 1, 2009, to May 5, 2012, we recorded height, weight, age, sex, ETT inner diameter, and cm marking at the lip from the electronic health record. Chest radiographs of poor quality and with spinal or skeletal deformities were excluded. We defined adherence to Pediatric Advanced Life Support or Neonatal Resuscitation Program guidelines as the difference between predicted and actual ETT markings at the lip as ± 0.25, ± 0.50, or ± 1.0 cm for ETTs of 2.5-4, 4.5-6.0, or >6.5 mm inner diameter, respectively. We defined the proper position as the ETT tip being below the thoracic inlet (superior border of the clavicular heads) and ≥1 cm above the carina. Descriptive statistics reported demographics, guideline adherence, and malposition incidence. The chi-square test was used to assess relationships among intubation setting, malposition, and depth guideline adherence (P < .05, significant). RESULTS: We reviewed 507 records, 477 of which met inclusion criteria and had sufficient data for analysis. Fifty-six percent of the subjects were male, with median (interquartile range) age 15.2 (3.4-59.4) months, and 330 ETTs (69%) were malpositioned: 39 above the thoracic inlet, and 291 < 1 cm above the carina. Of 79 ETTS (17%) that adhered to depth guidelines, 56 (74%) were malpositioned. Three-hundred seventy-three ETTs (83%) did not meet guidelines. Two-hundred sixty-four (68%) were malpositioned. The intubation setting did not influence malposition or guideline adherence (P = .54). CONCLUSIONS: In infants and children, a high proportion of ETTs were malpositioned on the first postintubation chest radiograph, with little influence of guideline adherence.

Ventilator Boot Camp Improves the Knowledge and Skills Associated With Mechanical Ventilator Use During Interfacility Transport of Intubated Pediatric Patients.

BACKGROUND: The American Academy of Pediatrics Section on Transport recommends the use of portable ventilators during the transport of patients with advanced airways. We sought to identify knowledge gaps and evaluate the effectiveness of a transport ventilator competency boot camp. METHODS: Electronic health records of children requiring ventilatory support during air and ground interfacility transport from January 1 through December 31, 2015, were reviewed to determine when manual ventilation was used in lieu of a portable ventilator, and simulations were constructed from commonly occurring scenarios. All registered respiratory therapists trained in air and ground critical-care transports participated. Demographic data were collected. We assessed performance on 3 facilitated simulated scenarios using a ventilator connected to a low-fidelity pediatric mannequin attached to breathing simulator. Scores were based on the participants' ability to correctly perform pre-use checks, select and optimize ventilator settings, set alarms, and complete safety checks. A 60-min interactive education intervention was conducted between the pre- and post-assessments. The pre-assessment, intervention, and post-assessment were conducted 6 weeks apart. De-identified assessments were scored, and results were shared after study completion. Descriptive statistics reported participant demographics. Paired t tests compared before and after assessments. Statistical significance was established at P < .05. RESULTS: A total of 172 electronic health records were reviewed. Manual ventilation was used more frequently in toddlers requiring pressure control ventilation; noninvasive ventilation was rarely used. A total of 17 registered respiratory therapists participated; 18% were male, 41% had 6-9 years of tenure and 5 years of experience with our transport team. Completing ventilator pre-use check and engaging alarms provided the most opportunity for improvement. Improvements were greater with the use of noninvasive ventilation (P = .006) than pressure control ventilation (P = .10) and volume control ventilation use (P = .07). CONCLUSIONS: Quality data were useful in identifying areas requiring knowledge and competency assessment. Re-assessment results validated the need to conduct education and competency assessment at defined intervals.

Validating Lung Models Using the ASL 5000 Breathing Simulator.

OBJECTIVE: This study sought to validate pediatric models with normal and altered pulmonary mechanics. METHODS: PubMed and CINAHL databases were searched for studies directly measuring pulmonary mechanics of healthy infants and children, infants with severe bronchopulmonary dysplasia and neuromuscular disease. The ASL 5000 was used to construct models using tidal volume (VT), inspiratory time (TI), respiratory rate, resistance, compliance, and esophageal pressure gleaned from literature. Data were collected for a 1-minute period and repeated three times for each model. t tests compared modeled data with data abstracted from the literature. Repeated measures analyses evaluated model performance over multiple iterations. Statistical significance was established at a P value of less than 0.05. RESULTS: Maximum differences of means (experimental iteration mean - clinical standard mean) for TI and VT are the following: term infant without lung disease (TI = 0.09 s, VT = 0.29 mL), severe bronchopulmonary dysplasia (TI = 0.08 s, VT = 0.17 mL), child without lung disease (TI = 0.10 s, VT = 0.17 mL), and child with neuromuscular disease (TI = 0.09 s, VT = 0.57 mL). One-sample testing demonstrated statistically significant differences between clinical controls and VT and TI values produced by the ASL 5000 for each iteration and model (P < 0.01). The greatest magnitude of differences was negligible (VT < 1.6%, TI = 18%) and not clinically relevant. CONCLUSIONS: Inconsistencies occurred with the models constructed on the ASL 5000. It was deemed accurate for the study purposes. It is therefore essential to test models and evaluate magnitude of differences before use.

Evaluation of Functional Characteristics of 4 Oscillatory Positive Pressure Devices in a Simulated Cystic Fibrosis Model.

BACKGROUND: Oscillatory positive expiratory pressure (OPEP) is an airway clearance therapy that delivers positive pressure and air-flow oscillations during exhalation. This study described functional characteristic differences of 4 OPEP devices during an active exhalation in a simulated model. We hypothesized peak pressure (Ppeak), positive expiratory pressure (PEP), oscillatory frequency (f), and pressure amplitude will differ, depending upon the device used, device resistance setting, and time (repeated consecutive active exhalations through the device). METHODS: The ASL 5000 was scripted to simulate pulmonary mechanics of a pediatric cystic fibrosis patient with moderate to severe lung disease. Airway resistance was standardized at 17.1 cm H2O/L/s, pulmonary compliance at 42.1 mL/cm H2O, active exhalation at 22 breaths/min, and tidal volume at 409 mL. Resistance settings for the Acapella, RC-Cornet, Flutter, and Aerobika were adjusted to low, medium, and high. Values for f, Ppeak, PEP, and pressure amplitude were recorded for 1 min and graphically displayed. RESULTS: Significant effects for time, device, and resistance (P < .01) were noted for Ppeak, PEP, and pressure amplitude at each resistance level, demonstrating that the devices functioned differently as more than one repetition of a series of consecutive active exhalations are performed. Significant interaction effects for device, resistance level, and time indicate inconsistent output for Ppeak (P < .01), PEP (P < .01), and pressure amplitude (P < .01). Oscillatory f values fell within the respective manufacturers' operational parameters. The Aerobika provided the most consistent pressure amplitude across resistance settings and produced the highest mean pressure amplitude at medium and high resistance settings. CONCLUSIONS: Statistically significant and clinically relevant variations in Ppeak, PEP, and pressure amplitude occurred between devices and within a device, as the resistance setting changed. The combination of device, time, and resistance settings affects OPEP device output for pressure, amplitude, and oscillatory frequency. Functional variations may impact therapeutic effectiveness, warranting additional study to determine clinical impact.

Reducing Unplanned Extubations in the NICU Using Lean Methodology.

BACKGROUND: Unplanned extubations can lead to iatrogenic injury and have the potential to contribute to serious safety events. We adopted lean methodology to reduce the unplanned extubation rate in a Level 3b NICU. We hypothesized that the use of a rapid-cycle PDSA (plan, do, study, act) initiative would reduce the unplanned extubation rate. METHODS: Baseline unplanned extubation data were collected from November 1, 2012 to June 6, 2014. A voice of the customer survey ascertained perceptions regarding unplanned extubation causes and impact on care. The confidential survey contained 2 open-ended and 4 closed-ended questions and was distributed to a random sample of nurses and respiratory therapists. A fishbone diagram helped to identify opportunities. Six improvements were identified and rolled out in 2 phases using didactic and kinesthetic techniques. Phase 1 standardized the process for turning intubated infants, assessing endotracheal tube (ETT) placement with growth, and communicating tube position with caregivers. Phase 2 addressed respiratory plans of care, correcting ETT migration, establishing ETT re-securement methods, and standardizing position during radiography. The Fisher exact test was used to determine differences in the number of unplanned extubations per 100 intubated days. Descriptive statistics were used to report survey results. Statistical significance was established at P < .05. RESULTS: A 68% (17 of 25) survey response rate was realized. Baseline data revealed 3.8 unplanned extubations/100 intubated days, and 2.7 unplanned extubations/100 intubated days occurred in the post-improvement phase (P = .01). We noted a statistically significant decrease in the number of intubated days between the pre- and post-improvement groups (P < .001). CONCLUSIONS: Staff underestimated the prevalence of unplanned extubations but recognized the need for improvement. Rapid cycle PDSA significantly reduced the unplanned extubation rate. The decrease in intubated days may have been a by-product of the post-improvement phase improvements, which encouraged practice changes.

Evaluating the Effect of Flow and Interface Type on Pressures Delivered With Bubble CPAP in a Simulated Model.

BACKGROUND: Bubble CPAP, used for spontaneously breathing infants to avoid intubation or postextubation support, can be delivered with different interface types. This study compared the effect that interfaces had on CPAP delivery. We hypothesized that there would be no difference between set and measured levels between interface types. METHODS: A validated preterm infant nasal airway model was attached to the ASL 5000 breathing simulator. The simulator was programmed to deliver active breathing of a surfactant-deficient premature infant with breathing frequency at 70 breaths/min inspiratory time of 0.30 s, resistance of 150 cm H2O/L/s, compliance of 0.5 mL/cm H2O, tidal volume of 5 mL, and esophageal pressure of -10 cm H2O. Nasal CPAP prongs, size 4030, newborn and infant RAM cannulas were connected to a nasal airway model and a bubble CPAP system. CPAP levels were set at 4, 5, 6, 7, 8, and 9 cm H2O with flows of 6, 8, and 10 L/min each. Measurements were recorded after 1 min of stabilization. The analysis was performed using SAS 9.4. The Kolmogorov-Smirnov test assessed normality of the data. The Friedman test was used to compare non-normally distributed repeated measures. The Wilcoxon signed-rank test was used to conduct post hoc analysis. All tests were 2-sided, and P values of <.05 were considered as indicating significant differences unless otherwise indicated. RESULTS: At lower set CPAP levels, 4-6 cm H2O, measured CPAP dropped precipitously with the nasal prongs with the highest flow setting. At higher CPAP levels, 7-9 cm H2O measured CPAP concomitantly increased as the flow setting increased. Statistically significant differences in set and measured CPAP occurred for all devices across all CPAP levels, with the measured CPAP less than set for all conditions, P < .001. CONCLUSIONS: Set flow had a profound effect on measured CPAP. The concomitant drop in measured pressure with high and low flows could be attributed to increased resistance to spontaneous breathing or insufficient flow to meet inspiratory demand. Clinicians should be aware of the effect that the interface and flow have on CPAP delivery.

AARC Clinical Practice Guideline: Effectiveness of Pharmacologic Airway Clearance Therapies in Hospitalized Patients.

Aerosolized medications are used as airway clearance therapy to treat a variety of airway diseases. These guidelines were developed from a systematic review with the purpose of determining whether the use of these medications to promote airway clearance improves oxygenation and respiratory mechanics, reduces ventilator time and ICU stay, and/or resolves atelectasis/consolidation compared with usual care. Recombinant human dornase alfa should not be used in hospitalized adult and pediatric patients without cystic fibrosis. The routine use of bronchodilators to aid in secretion clearance is not recommended. The routine use of aerosolized N-acetylcysteine to improve airway clearance is not recommended. Aerosolized agents to change mucus biophysical properties or promote airway clearance are not recommended for adult or pediatric patients with neuromuscular disease, respiratory muscle weakness, or impaired cough. Mucolytics are not recommended to treat atelectasis in postoperative adult or pediatric patients, and the routine administration of bronchodilators to postoperative patients is not recommended. There is no high-level evidence related to the use of bronchodilators, mucolytics, mucokinetics, and novel therapy to promote airway clearance in these populations.

Neonatal respiratory therapist-led rounds can improve staff satisfaction and timeliness of respiratory interventions.

BACKGROUND: Interdisciplinary rounding is used to establish and communicate patient care goals and monitor progress toward goal attainment. This study describes staff satisfaction and process outcomes associated with respiratory therapist (RT)-led interdisciplinary rounds in the neonatal ICU. We hypothesized improved staff satisfaction, execution of orders within 30 min of order entry into the electronic medical record, and communication of accurate and complete data during rounds to the interdisciplinary team. METHODS: Nurses, RTs, nurse practitioners, residents, and attending physicians completed the 13-question survey eliciting demographic information and evaluating staff engagement and professional satisfaction. The survey was anonymous and confidential, and informed consent was implied. Process data were collected for a 10-d period at 2 intervals through direct observation of the rounding process and electronic medical record review. Descriptive statistics reported patient demographics, responses to job satisfaction and engagement survey questions, the number of patients who were visited in daily rounds, the number and type of orders given during rounds, and the number of respiratory orders that were addressed in multidisciplinary teaching rounds rather than during respiratory rounds. The chi-square test was used to determine differences in the proportion of inaccurate and incomplete data communicated during rounds between the 2 data collection periods. The Mann-Whitney U test was used to determine differences in the timeliness of electronic medical record order entry and time to order completion. RESULTS: A 94.8% survey response rate (n = 55) was obtained. Seventy-six percent of participants reported improved communication. Sixty-nine percent of participants reported improved teamwork. Eighty-six percent of orders were implemented immediately after electronic medical record entry. Correct information was provided on 95% and 99.3% of patients (P < .066) and complete information on 93% and 96% of patients (P = .41). CONCLUSIONS: Implementation of respiratory rounds improved staff satisfaction and the timeliness of completing respiratory orders. Spot monitoring at intermittent intervals verified process sustainability.

Body mass index moderates the effects of portable oxygen transport modality on 6-minute walk distance in patients with COPD.

PURPOSE: While portable, supplemental oxygen is often necessary for patients with chronic obstructive pulmonary disease (COPD) to retain independence, it may provide functional limitations because of the increased workload imposed. This issue may result in nonuse, creating a need to identify carrying modalities that optimize transport. This study assessed the effects of 3 methods of portable oxygen transport on 6-minute walk distance (6 MWD), rate of perceived exertion (RPE), heart rate (HR), and oxyhemoglobin saturation (SpO2). As weight status is known to impact functional ability in COPD, effects of body mass index (BMI) were also assessed. METHODS: Data were analyzed using the mixed-model procedure to test for effects of transport modality (reference, rolling cart, backpack, shoulderstrap), time (minutes 1-6), BMI, non-overweight, overweight, and interactions of these variables on outcome parameters. RESULTS: A main effect of condition was found for 6 MWD, and an interaction of condition × BMI was found for HR and RPE, and of time × BMI for 6 MWD and SpO2. Participants walked the least distance in rolling cart condition, which was also characterized by the greatest RPE. For the overweight group, HR was least in the reference compared with other conditions; but for the non-overweight group, the opposite pattern was observed. At latter time points, 6 MWD was greater in the non-overweight group, while SpO2 was reduced. CONCLUSION: Results demonstrate that transport modality of portable oxygen exerts differential effects on functional performance in COPD patients and that BMI may moderate underlying physiologic factors that contribute to performance outcomes.