Resp Care
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Comparative Study
Influence of nebulizer type with different pediatric aerosol masks on drug deposition in a model of a spontaneously breathing small child.
The performance of nebulizers varies with the design type as well as the breathing patterns of various age groups. The present study quantified aerosol delivery using spontaneously breathing parameters of a small child (2-4 years) by a lung simulator to determine the influence of nebulizer type, actuation mechanisms, and pediatric aerosol masks. ⋯ In this model using ventilatory parameters associated with a 2-4-year-old child, breath-actuated nebulization was not as effective as continuous nebulization. Aerosol mask design can impact inhaled drug dose across the range of nebulizers tested.
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High-frequency oscillatory ventilation (HFOV) has been utilized as a rescue oxygenation therapy in adults with ARDS over the last decade. The HFOV oscillating piston can generate negative pressure during the exhalation cycle, which has been termed active exhalation. We hypothesized that this characteristic of HFOV entrains CO(2) into the inspiratory limb of the circuit and increases the total dead space. The purpose of this study was to determine if retrograde CO(2) entrainment occurs and how it is altered by HFOV parameter settings. ⋯ Retrograde CO(2) entrainment occurs during HFOV use and can be manipulated with the ventilator settings. This phenomenon may have clinical implications on the development or persistence of hypercapnia.
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Case Reports
Dexmedetomidine for sedation in the parturient with respiratory failure requiring noninvasive ventilation.
Dexmedetomidine is a selective alpha-2 receptor agonist that possesses both sedative and analgesic properties, with minimal respiratory depression. We report the successful administration of dexmedetomidine on a 16-year-old primigravida woman that allowed the patient to tolerate application of bi-level positive airway pressure ventilation in treatment of acute hypoxemic respiratory failure.
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When obtaining an arterial blood sample via percutaneous puncture, there is a risk of accidentally obtaining venous blood. Conventional methods of confirming arterial blood at the bedside, such as blood color and pulsatile return, can be misleading in patients with low blood pressure or hypoxemia. ⋯ Our results were consistent with a laboratory study showing a significant difference between arterial and venous filling times and a negative correlation between mean arterial pressure and sampler filling time, but our times in adult subjects were longer. Respiratory therapists may find arterial sampler filling time as a useful indicator of successful arterial puncture at the bedside.
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Practice Guideline
AARC clinical practice guideline: transcutaneous monitoring of carbon dioxide and oxygen: 2012.
An electronic literature search for articles published between January 1990 and September 2011 was conducted by using the PubMed, CINAHL, SCOPUS, and Cochrane Library databases. The update of this clinical practice guideline is the result of reviewing a total of 124 articles: 3 randomized controlled trials, 103 prospective trials, 1 retrospective study, 3 case studies, 11 review articles, 2 surveys and 1 consensus paper on transcutaneous monitoring (TCM) for P(tcO(2)) and P(tcCO(2)). The following recommendations are made following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria: (1) Although P(tcCO(2)) has a good correlation with P(aCO(2)) and is a reliable method to evaluate plasma CO(2) levels, it is recommended that arterial blood gas values be compared to transcutaneous readings taken at the time of arterial sampling, in order to verify the transcutaneous values, and periodically as dictated by the patient's clinical condition. (2) It is suggested that P(tcCO(2)) may be used in clinical settings where monitoring the adequacy of ventilation is indicated. (3) It is suggested that P(tcO(2)) and P(tcCO(2)) may be used in determining the adequacy of tissue perfusion and monitoring of reperfusion. (4) It is suggested that TCM should be avoided in the presence of increased thickness or edema of the skin and/or subcutaneous tissue where the sensor is applied. (5) It is recommended that sites used for a TCM be changed as often as necessary and that they be alternated and observed to avoid thermal injury. Manufacturer recommendations should be followed.