The Journal of Emergency Medicine 567

and creates an air seal using a silicon gasket around the perim-eter of the face, theoretically eliminating discomfort to the nasalbridge and simplifying mask application. Of 60 patients en-rolled in the study, 31 were randomized to the ONM groupand 29 to the TFM group. There was no statistically significantdifference in baseline characteristics including sex, age, vitalsigns, arterial blood gas values, dyspnea score, and indicationfor NIV between groups, except for a higher heart rate in theTFM group (102.4 6 20.8 beats/min vs. 116.0 6 19.1 beats/min). There was no significant difference in the primary out-comes of mask discomfort (graded using a visual analog scale0, 30, and 180 min after initiation of mask use) and time re-quired for mask placement (3.5 vs. 5 min, p < 0.05). Secondaryoutcomes were changes in dyspnea (also graded using a visualanalog scale at baseline, 30 min, and 1, 3, and 24 h of NIV),gas exchange, vital signs, and early NIV discontinuation. Ter-tiary outcomes included length of NIV use, length of hospitalstay, intubation, and in-hospital mortality. The only statisticallysignificant difference found was a greater decrease in heart rateat 3 h in the TFM group, although this group also had a greaterbaseline heart rate. Although there was no difference in earlyNIV discontinuation rates (40% in the ONM group vs. 57.1%,p > 0.05), 8 patients in the TFM group were switched to theONM, whereas no members of the ONM group were switchedto TFM.

[Omeed Saghafi, MD

Denver Health Medical Center Denver, CO]

Comment:Although this study was a well-designed prospec-tive study, it had a couple of important limitations. Most obvi-ously, blinding was not possible, making patients andrespiratory therapists potentially biased towards the more famil-iar ONM. Secondly, the study size was quite small, potentiallyleading to a type II error. Finally, although 60 patients were en-rolled in the study, 5 additional patients were evaluated for en-rollment but were excluded due to inability to fit the mask (4 inthe TFM group and 1 in the ONM group), results that may haveaffected the primary outcomes. Despite this, it is useful to notethat this study demonstrated that the TFM does not provide anysignificant advantages over the ONM, but is a comparable alter-native to the ONM.

, FOCUSED ASSESSMENT OF PATIENTS WITHASTHMAINTHEEMERGENCYDEPARTMENT.KanisK,Lovell J, Bowan M, Titus MO. Clin Pediatr 2011;50:529–34.

Asthma accounts for approximately 20 million visits toemergency departments (EDs) across the country every year.Clinical asthma severity (CAS) scores have been developed inan attempt to improve and standardize asthma care during acuteexacerbations. In this retrospective chart review, Kanis et al. at-tempted to determine whether the adoption of a CAS score forpediatric patients within their large urban ED improved identi-fication of patients with severe asthma and increased the aggres-siveness of treatment received. When comparing all asthmapatients seen within their ED in the 18 months preceding theimplementation of a CAS score to the first 18 months after theimplementation of the CAS score, there were little differencesin the percentage of patients admitted to the hospital

(pre-CAS 21%, post-CAS 21%), the number of continuousdoses of albuterol (pre-CAS 2.0 doses per visit, post-CAS 2.5doses per visit), or the average hospital length of stay (pre-CAS 2.4 days, post-CAS 2.7 days), although the percentage ofpatients admitted to the pediatric intensive care unit increased(pre-CAS 16%, post-CAS 21%). The authors went on to com-pare all patients admitted to the hospital in the 18 months pre-ceding the implementation of the CAS to all patients in the 18months after implementation with a CAS > 5. Although notall patients in the second group were admitted to the hospital,this second group had an increased use of magnesium (pre-CAS 28%, post-CAS 38%) and a decreased percentage of chestX-ray studies ordered (pre-CAS 78%, post-CAS 50%), althoughonly the decrease in the use of chest X-ray studies was statisti-cally significant. The authors concluded that the implementationof the CAS score led to an increase in therapeutic intensity.

[Austin Johnson, MD

Denver Health Medical Center, Denver, CO]

Comment: The use of asthma severity scores is gaining pop-ularity within EDs. There are a number of factors that make theabove results difficult to interpret. First, the groups that werecompared within this study are not similar; most importantly,in the pre-CAS group all the patients were admitted, whereasin the post-CAS group a significant portion of the patientswere discharged home. Secondly, it is unclear how the CASscore was used by the treating physician in determining care.With these limitations, the lack of statistical significance forthe majority of treatment outcomes suggests that the CAS scorehad little effect on physicians’ actions. Finally, the lack of anylong-term outcomes, including mortality or repeat attacks,makes it unclear whether this increased use of resourcesimproved patient outcomes.

, THE EFFECT OF SUPPLEMENTAL OXYGEN ONHYPERCAPNIA IN SUBJECTS WITH OBESITY-ASSO-CIATED HYPOVENTILATION: A RANDOMIZED,CROSSOVER, CLINICAL STUDY.Wijesinghe M, WilliamsM, Perrin K, Weatherall M, Beasley R. Chest 2011;139:1018–24.

It is well known that supplemental oxygen can cause wors-ening hypercapnia in patients with chronic obstructive pulmo-nary disease. This study sought to determine if the same effectis seen in patients with obesity-associated hypoventilation(OAH). In this double-blind, randomized, controlled, crossovertrial of 24 patients newly diagnosed with OAH, subjects inhaledeither 100% oxygen or room air via full-face continuous posi-tive airway pressure mask, without positive airway pressure,for 20 min on 2 separate days. Baseline measurements of trans-cutaneous carbon dioxide tension (PtCO2), minute ventilation,and volume of dead-space-to-tidal-volume ratio were comparedto the same values at 20 min by mixed linear model to determinedifferences between the two treatments. All subjects who com-pleted the study (23 of 24) participated in both of the treatmentson separate days within 7 days. Testing was terminated early in3 subjects while breathing 100% oxygen secondary to a rise inPtCO2 of $ 10 mm Hg, whereas none of the patients breathingroom air required early termination of the treatment protocol.