To describe the neural breathing pattern before and after extubation in newborn infants. Prospective, observational study. In infants deemed ready for extubation, the diaphragm electrical activity (EAdi) was continuously recorded from 30... more
To describe the neural breathing pattern before and after extubation in newborn infants. Prospective, observational study. In infants deemed ready for extubation, the diaphragm electrical activity (EAdi) was continuously recorded from 30 minute before to 2 hours after extubation. Total of 25 neonates underwent 29 extubations; 10 extubations resulted in re-intubation within 72 hours. Postextubation, there was an increase in peak EAdi (EAdi-max) and EAdi delta (peak minus minimum EAdi) in both groups. The pre to post extubation change in EAdi-max (8.9 to 11.1 μv) and EAdi-delta (6 to 8 μv) was less in the failure group in comparison to the change in EAdi-max (10.2 to 13.4 μv) and EAdi delta (6.3 to 10.6 μv) in the success group, (p= 0.02 and 0.01 respectively). In our neonatal cohort, extubation failure was associated with a smaller increase in peak and delta EAdi after extubation. If confirmed, these findings indicate an important cause of extubation failure in preterm infants. This ...
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Simple and accurate expressions describing the PaO2-FiO2 relationship in mechanically ventilated patients are lacking. The current study aims to validate a novel mathematical expression for accurate prediction of the fraction of inspired... more
Simple and accurate expressions describing the PaO2-FiO2 relationship in mechanically ventilated patients are lacking. The current study aims to validate a novel mathematical expression for accurate prediction of the fraction of inspired oxygen that will result in a targeted arterial oxygen tension in non-smoking and smoking patients receiving mechanical ventilation following open heart surgeries. One hundred PaO2-FiO2 data pairs were obtained from 25 non-smoking patients mechanically ventilated following open heart surgeries. One data pair was collected at each of FiO2 of 40, 60, 80, and 100% while maintaining same mechanical ventilation support settings. Similarly, another 100 hundred PaO2-FiO2 data pairs were obtained from 25 smoking patients mechanically ventilated following open heart surgeries. The utility of the new mathematical expression in accurately describing the PaO2-FiO2 relationship in these patients was assessed by the regression and Bland-Altman analyses. Significan...
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Mid-frequency ventilation, a strategy of using conventional ventilators at high frequencies, may reduce lung injury but has had limited evaluation in neonates. Hence, a randomized crossover study was designed to assess the feasibility of... more
Mid-frequency ventilation, a strategy of using conventional ventilators at high frequencies, may reduce lung injury but has had limited evaluation in neonates. Hence, a randomized crossover study was designed to assess the feasibility of using mid-frequency ventilation in preterm infants with respiratory distress syndrome. Twelve preterm infants (≥500 g and ≥24 weeks gestational age) who were receiving pressure-limited conventional ventilation with frequencies ≤60 breaths/min for respiratory distress syndrome were randomized to periods of mid-frequency ventilation (conventional ventilation with the fastest frequency up to 150 breaths/min that gave complete inspiration and expiration) or conventional ventilation (frequency ≤60 breaths/min), each lasting 2 h using a crossover design. Ventilator parameters were adjusted to maintain the O2 saturation and transcutaneous CO2 at baseline. Mean peak inspiratory pressure (15 ± 4 cm H2O vs 18 ± 4 cm H2O, P < .001), Δ pressure (9.8 ± 3.3 cm...
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The clinical application of high frequency jet ventilation (HFJV), especially in pediatrics, has been hindered by the lack of adequate heating and humidification of the delivered gas. A technique of injecting particulate water into the... more
The clinical application of high frequency jet ventilation (HFJV), especially in pediatrics, has been hindered by the lack of adequate heating and humidification of the delivered gas. A technique of injecting particulate water into the gas from the jet ventilator has been described in the literature. However, it has been used primarily on adults and may cause fluid overload or hypothermia when used on infants. We describe a device for use during HFJV that provides gas (free of particulate water) to the patient at or near body temperature, with a relative humidity of 91%. This system has been used on 34 persons (14 premature infants, 17 small children, and 3 adults) without complications associated with improper conditioning of inspired gas.
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a) To investigate whether the patient work of breathing needed to trigger inspiration is affected by the type of ventilator delivering pressure-support ventilation for mechanically ventilated pediatric patients. b) To determine whether... more
a) To investigate whether the patient work of breathing needed to trigger inspiration is affected by the type of ventilator delivering pressure-support ventilation for mechanically ventilated pediatric patients. b) To determine whether changes in oxygen consumption (VO2) trend with changes in work of breathing and would thus be helpful in tracking work of breathing. Prospective study. Pediatric intensive care unit at a university hospital. Nine mechanically ventilated patients (2 to 75 months of age). While maintaining a constant pressure-support ventilation level, patients were alternately supported with the Siemens Servo 900C, the Bird VIP, and the Newport Wave E200 ventilators in random order. Work of breathing, defined as the integral of the pressure-volume curve corresponding to negative pressure, was calculated with a pulmonary monitoring system. VO2 was measured with a metabolic cart. Patient distress levels were assessed using the COMFORT scale, a behavioral scoring system. Mean values (20 breaths/patient) for measured variables with each ventilator were compared using analysis of variance and Scheffé tests, with p &lt; .05 indicating statistical significance. The lowest VO2 (103 +/- 35 mL/min/m2) and work of breathing (24 +/- 15 g.cm/m2) were achieved with the Bird VIP ventilator and were significantly (p &lt; .05) lower than those values obtained with either the Siemens Servo 900C (VO2 147 +/- 33 mL/min/m2; work of breathing 49 +/- 18 g.cm/m2) or the Newport Wave E200 (VO2 122 +/- 33 mL/min/m2; work of breathing 35 +/- 15 g.cm/m2). Also, the values of work of breathing and VO2 obtained using the Newport Wave E200 were significantly (p &lt; .05) lower than those values obtained using the Servo 900C. No change in behavioral distress occurred when the ventilators were changed. In all patients, there was a clear similarity in the trends of VO2 and work of breathing. We conclude that VO2 and work of breathing may be reduced significantly using the latest generation of mechanical ventilators optimized for infant and pediatric use. Because work of breathing is less with the Bird VIP than the other two ventilators tested, leading to a corresponding decrease in VO2, we suggest that the Bird VIP better adapts the patient to the ventilator and may facilitate weaning from ventilatory support. We also suggest that changes in VO2 might be helpful in tracking changes in work of breathing.
Research Interests: Nursing, Critical Care, Critical Care Medicine, Prospective studies, Humans, and 12 moreChild, Female, Animals, Male, Infant, Clinical Sciences, Public health systems and services research, Analysis of Variance, Mechanical Ventilation, Oxygen Consumption, Severity of Illness Index, and Child preschool
The immediate survival of infants with hypoplastic left heart syndrome depends on success in achieving several therapeutic goals: (1) maintain patency of the ductus arteriosus, (2) assure adequate mixing of blood at the atrial level, and... more
The immediate survival of infants with hypoplastic left heart syndrome depends on success in achieving several therapeutic goals: (1) maintain patency of the ductus arteriosus, (2) assure adequate mixing of blood at the atrial level, and (3) establish and maintain a balance between systemic and pulmonary blood flow at or near unity. In accomplishing that final goal, various ventilatory strategies have been used to alter the physiologic modifiers of pulmonary vascular resistance and thus maintain balanced circulation, including ventilation with gas of subatmospheric oxygen concentration. However, no data on this subject have been published in the scientific literature, and commercial oxygen analyzers are specified for use within the range of 0.21 to 1.0 fraction of inspired oxygen (F(IO)(2)), leaving the accuracy of hypoxic gas delivery somewhat uncertain. We evaluated the performance of oxygen analyzers below F(IO)(2) 0.21. Two commercially available analyzers were studied: the TED-190 (Teledyne) and the Mini-OX III. Five new analyzers of each model were tested. After a 2-point calibration (F(IO)(2) 1.0 and 0.21), all 5 analyzers of the same model were simultaneously exposed to precision-blended gases at 6 different concentrations of oxygen in nitrogen. Steady state was maintained for at least 2 min at each concentration before readings were recorded. Calibration was verified at F(IO)(2) 0.21 between each level. The mean +/- SD error was 0.0013 +/- 0.0021 for the Mini-OX III analyzers and -0.0004 +/- 0.0009 for the Teledyne analyzers. The upper and lower limits of the 95% confidence interval were 0.39% and -0.13% for the Mini-OX III analyzers and 0.07% and -0.15% for the Teledyne analyzers. The maximum difference between measured and known oxygen concentrations was 1% of full scale. The Mini-OX III and the Teledyne TED-190 provide accurate and reliable F(IO)(2) readings between 0 and 0.21 that are within the manufacturers&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; specifications for maximum error. These 2 analyzers are therefore acceptable for use in delivering subambient oxygen concentrations. The Mini-OX III displays oxygen concentration to the nearest 0.1% and may be more appropriate for precise control.
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ABSTRACT Mechanical ventilation is a life-saving intervention for respiratory failure and thus has
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Research Interests: Leadership, Treatment, Respiratory therapy, Teamwork, Humans, and 9 moreOrganization, Clinical Sciences, Organizational Innovation, Cooperative Behavior, Respiratory Care, Organizational case studies, personnel staffing and scheduling, Outcome assessment (Health care), and Cardiovascular medicine and haematology
To identify tracheobronchial abnormalities associated with assisted ventilation, 40 infants with respiratory distress syndrome randomized to receive either short-term (48 hours) conventional or high-frequency jet ventilation were studied.... more
To identify tracheobronchial abnormalities associated with assisted ventilation, 40 infants with respiratory distress syndrome randomized to receive either short-term (48 hours) conventional or high-frequency jet ventilation were studied. Flexible fiberoptic bronchoscopy (n = 13) was performed and/or clinical and radiographic assessments were used to evaluate for laryngeal, tracheal, and bronchial lesions. There was no bronchoscopic evidence of necrotizing tracheobronchitis after either high-frequency jet ventilation (n = 8) or conventional ventilation (n = 5). Laryngotracheomalacia and nodular vocal cords were the most common abnormalities noted, and they occurred with equal frequency in both groups. Study infants who were not bronchoscoped had no clinical or radiographic evidence of tracheal or mainstem bronchial obstruction. One patient did have microscopic evidence of necrotizing tracheobronchitis at autopsy, however. It is concluded that short-term treatment of respiratory distress syndrome with high-frequency jet ventilation may be performed without undue risk of tracheobronchial injury.
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Research Interests: Decision Making, Evidence Based Medicine, Asthma, Critical Care, Aerosols, and 15 moreHumans, Anoxia, Helium, Length of Stay, Clinical Sciences, Cardiopulmonary Resuscitation, Immunocompromised host, Body Weight, Clinical Protocols, Capnography, Clinical Trials as Topic, Combined Modality Therapy, Acute Disease, Heart arrest, and Cardiovascular medicine and haematology
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Research Interests: Anthropometry, Electronic Health Records, Humans, Female, Male, and 14 moreClinical Sciences, Ulna, Adult, Sex Factors, European Continental Ancestry Group, Body Weight, Intensive Care Units, Body Height, Predictive value of tests, Respiratory Care, Ventilator induced lung injury, Tidal volume, Data Accuracy, and Cardiovascular medicine and haematology
Mechanical ventilators can be understood in terms of simple physical models that have electrical analogs. These models provide the basis for designing and classifying ventilators as well as understanding ventilator-patient interactions.
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Page 1. Endotracheal Suctioning of Mechanically Ventilated Adults and Children with Artificial Airways Richard D. Branson, RRT Robert S. Campbell, RRT Robert L. Chatburn, RRT Jack Covington, RRT Mechanical Ventilation ...
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Numerous ventilation modes and ventilation options have become available as new mechanical ventilators have reached the market. Ventilator manufacturers have no standardized terminology for ventilator modes and ventilation options, and... more
Numerous ventilation modes and ventilation options have become available as new mechanical ventilators have reached the market. Ventilator manufacturers have no standardized terminology for ventilator modes and ventilation options, and ventilator operator's manuals do not help the clinician compare the modes of ventilators from different manufacturers. This article proposes a standardized system for classifying ventilation modes, based on general engineering principles and a small set of explicit definitions. Though there may be resistance by ventilator manufacturers to a standardized system of ventilation terminology, clinicians and health care equipment purchasers should adopt such a system in the interest of clear communication--the lack of which prevents clinicians from fully understanding the therapies they administer and could compromise the quality of patient care.
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No objective data directly comparing the 2 modes are available. Based on a simple mathematical model, APRV and BIPAP can presumably be set to achieve the same mean airway pressure (mPaw), end expiratory pressure, and tidal volume (V(T)).... more
No objective data directly comparing the 2 modes are available. Based on a simple mathematical model, APRV and BIPAP can presumably be set to achieve the same mean airway pressure (mPaw), end expiratory pressure, and tidal volume (V(T)). Herein, we tested this hypothesis when using a real ventilator and clinically relevant settings based on expiratory time constants. A spontaneously breathing acute respiratory distress syndrome patient was modeled with a lung simulator. Mode settings: P high and the number of releases were the same in both modes; T low=1 time constant in APRV (expected auto-positive end-expiratory pressure [PEEP], ≈9 cmH(2)O) and 5 time constants in BIPAP; P low, 0 cmH(2)O in APRV and 9 cmH(2)O in BIPAP (equal to the expected auto-PEEP in APRV). The mean mandatory release volumes, minute ventilation [V(E)], mPaw, and total PEEP were compared with t-tests using a P value of 0.05 to reject the null hypothesis. APRV yielded significantly higher mPaw than did BIPAP. Min...
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As hospitals begin to implement electronic medical records, the inadequacies of legacy paper charting systems will become more evident. One area of particular concern for respiratory therapists is the charting of mechanical ventilator... more
As hospitals begin to implement electronic medical records, the inadequacies of legacy paper charting systems will become more evident. One area of particular concern for respiratory therapists is the charting of mechanical ventilator settings. Our profession's lack of a standardized and generally accepted taxonomy for mechanical ventilation leaves us with a confusing array of terms related to ventilator settings. Such confusion makes database design impossible for information technology professionals and is a risk-management concern for clinicians. Of particular note is the complexity related to set airway pressures when using modes whose primary control variable is pressure (versus volume). We review the clinically relevant issues surrounding documentation of the patient-ventilator interactions related to airway pressure and provide suggestions for a standardized vocabulary.