Journal of Pediatric Intensive Care - Volume 2, issue 1

Authors: Heulitt, Mark J.

Article Type: Other

DOI: 10.3233/PIC-13041

Citation: Journal of Pediatric Intensive Care, vol. 2, no. 1, pp. 1-3, 2013

Authors: Ranallo, Courtney D. | Heulitt, Mark J.

Article Type: Review Article

Abstract: Sleep is essential to a patient’s well-being. The importance of sleep is highlighted by the adverse effects in the wake of its absence both physically and mentally. Sleep is difficult to achieve in the intensive care unit due to noise, patient care activities, illness, and mechanical ventilation. Activities related to mechanical ventilation such as suctioning, discomfort of the essential tremor, alarms, treatments and sedation effects can all alter sleep architecture. However, mechanical ventilation itself especially as it relates to asynchrony may also play a larger role than previously thought. This paper aims to review sleep in the intensive care unit …and the relationship of mechanical ventilation. Show more

Keywords: Sleep, mechanical ventilation, sedation, delirium

DOI: 10.3233/PIC-13042

Citation: Journal of Pediatric Intensive Care, vol. 2, no. 1, pp. 5-10, 2013

Authors: Clement, Katherine C.

Article Type: Review Article

Abstract: Allowing spontaneous respiration during mechanical ventilation requires that the ventilator system can interpret a trigger signal from the patient and then deliver a synchronous breath. The majority of current ventilators are triggered by preset changes in pressure or flow detected in the system as a patient is initiating a breath. However, other triggers such as chest wall motion, waveform alteration, and diaphragmatic electromyograms have also been utilized. The time between initiation of a breath by a patient and delivery of a breath by the ventilator is known as trigger delay. Most trigger delay is inherent in the mechanics of the …patient-ventilator interaction. However, recent advances in technology have captured a neural signal from the diaphragm to trigger the ventilator to deliver a breath, reducing trigger delay. Understanding trigger delay is important as it may lead to increased work of breathing and patient-ventilator asynchrony. Types of asynchrony related to the triggering phase are ineffective triggering, double triggering, and autotriggering. The presence of asynchrony has been shown to have deleterious effects on patients, including duration of mechanical ventilation and increased length of hospital stay. Recognizing asynchrony and understanding how to manipulate the trigger variable will reduce adverse effects on patients. Show more

Keywords: Mechanical ventilation, triggering

DOI: 10.3233/PIC-13043

Citation: Journal of Pediatric Intensive Care, vol. 2, no. 1, pp. 11-18, 2013

Authors: Mireles-Cabodevila, Eduardo | Chatburn, Robert L. | Heulitt, Mark H.

Article Type: Review Article

Abstract: Mid-frequency ventilation (MFV) is a mode of mechanical ventilation where pressure controlled breaths are delivered at higher than usual respiratory rates with a conventional ventilator. The use of higher than normal frequencies has been used in clinical practice for the last 30 yr. However, MFV is based in the mathematical modeling of a pressure control breath; were as ventilator frequency increases, at a constant inspiratory to expiratory time ratio, alveolar ventilation demonstrates a peak (maximized). This peak is typically found at higher than usual respiratory rates (optimal frequency) and lower tidal volume (VT ). The clinical consequence is that for …a given alveolar ventilation target, MFV provides optimal inspiratory pressure and respiratory frequency with the least VT . MFV is a strategy where peak alveolar ventilation is identified and results in lower VT at the same ventilation pressures. Current ventilators are able to deliver higher rates and thus can optimize the delivery of mechanical ventilation. Current clinical practice of mechanical ventilation utilizes a low VT approach as a protective lung strategy to prevent further ventilator induced lung injury and thus potentially reduce mortality. Further, neonatal and pediatric patients who fail a conventional low VT protective lung strategy are transitioned to either high frequency ventilation, which delivers small VT at fast respiratory rates, or more invasive and expensive support such as extracorporeal membrane oxygenation. MFV may offer an alternative to deliver a protective lung strategy without the need for advanced equipment. Show more

Keywords: Mechanical ventilation, mid-frequency ventilation, lung injury, pressure control, acute respiratory distress syndrome

DOI: 10.3233/PIC-13044

Citation: Journal of Pediatric Intensive Care, vol. 2, no. 1, pp. 19-26, 2013

Authors: Heulitt, Mark J. | Holt, Shirley J. | Thurman, Tracy L.

Article Type: Research Article

Abstract: Optimal mechanical ventilation in infants and pediatrics depends on the reliability of flow sensors to correctly measure flow and integrate it into accurately displayed tidal volumes (VTE ). However, reliability of these devices has not been established. We hypothesize that reliability would be affected by both the type of flow sensors and ventilator controllers utilized. Intubated, sedated Sprague Dawley rats (n = 14) were ventilated (control and support modes) utilizing two different ventilators: 1) fixed orifice flow sensor (FOF) and 2) both a hot wire (HWF) and variable orifice flow sensor (VOF), independently. Accuracy of delivered tidal volume was obtained …by comparing the displayed volume of the different sensors to breath waveforms acquired using a heated 0–5 L/min calibrated pneumotachograph. Analysis was performed utilizing ANOVA with P ≤ 0.05. Rats mean weight was 472 ± 46 g. For all modes, mean VTE % difference was demonstrated across all three measuring sensors. For volume control ventilation and pressure control ventilation or time cycled pressure limited assist control, there was a difference between all three sensors. For pressure support ventilation, there was a difference with the HWF only. R-square values were FOF 0.80, HWF 0.54, and VOF 0.16. The accuracy of delivered VTE is affected by both the flow sensor and ventilator controller to deliver the breath. We speculate that the flow sensor and the controller are associated with varying degrees of flow accuracy and control. We would expect volume accuracy for all modes to be equal if the flow accuracy were related to the inaccuracy of the flow sensors only. Show more

Keywords: Pediatric, critical care, artificial, respiration, monitoring, ventilation

DOI: 10.3233/PIC-13045

Citation: Journal of Pediatric Intensive Care, vol. 2, no. 1, pp. 27-32, 2013

Authors: Heulitt, Mark J. | Holt, Shirley J. | Thurman, Tracy L.

Article Type: Research Article

Abstract: Goals of modern mechanical ventilation in infants focus on preventing over-distention by limiting tidal volume. Accurate measurement of these volumes is essential. We hypothesized that tidal volume accuracy differs dependent upon the type of airway sensor utilized in tidal volumes less than 10 mL. Intubated, sedated Sprague Dawley rats (n = 40) were ventilated utilizing both control and support ventilator modes. Accuracy of volume delivery was compared between a fixed orifice flow sensor (FOF) and a hot wire anemometer (HWA) to a Hans Rudolph linear pneumotachograph positioned at the patient wye. Rats median weight was 476 grams (range 370–544), tidal …volume (VT ) 3.5 mL (1.2–11.4), f 50 (18–102), and PIP 9.5 cm H2 O (1–34). Across all modes, bias and precision were HWA −0.76, 1.09; FOF 0.22, 0.61. This study confirms that there are differences in the accuracy of small tidal volumes measured with a FOF as compared to a HWA. Utilizing a FOF, control modes exhibit improved precision and decreased bias as compared to support modes. Show more

Keywords: Pediatric, critical care, artificial, respiration, monitoring, ventilation

DOI: 10.3233/PIC-13046

Citation: Journal of Pediatric Intensive Care, vol. 2, no. 1, pp. 33-38, 2013

Authors: Clement, Katherine C. | Thurman, Tracy L. | Holt, Shirley J. | Gibbs, Amy E. | Heulitt, Mark J.

Article Type: Research Article

Abstract: Using a mixture of helium and oxygen (heliox) while mechanically ventilating patients to relieve lower airway obstruction is commonly practiced in intensive care units. The use of heliox with commercially available mechanical ventilators is usually accomplished by connecting the heliox mixture to the air inlet of the ventilator. Since most ventilators do not compensate for the difference in gas densities, particular attention to the delivered tidal volume (VT ) is required. We utilized a commercially available mechanical ventilator with an internal blending system that is capable of delivering heliox instead of medical air. It identifies and compensates for the gas …mixture, theoretically enhancing stability in delivered and monitored parameters. Intubated, sedated male domestic pigs (n = 7) were ventilated with a mechanical ventilator equipped with an internal heliox blending system utilizing pressure assist control, pressure regulated volume control, and pressure support ventilation modes. Accuracy of volume delivery was assessed by comparing delivered VT measured at the patient wye using the variable orifice flow sensor connected to the ventilator and a heated 0–35 L/min pneumotachograph that was calibrated for flow, pressure, and volume, with a 0.80/0.20 heliox mix and 0.50 oxygen. A paired t-test was utilized with a P < 0.05. Pigs mean weight 9.0 ± 0.9 kg. Mean exhaled tidal volume for all modes and was 66 ± 16 mL. When comparing all modes for the 0.50 oxygen to the heliox mix, we found that exhaled tidal volume % difference increased when using heliox (P ≤ 0.037). This study confirms that clinicians should be vigilant in monitoring delivered VT using a commercially available ventilator equipped with an internal heliox blending system. Accuracy of delivered VT can vary greatly with the use of heliox in this system, as well as other configurations. Show more

Keywords: Pediatric, critical care, artificial respiration, monitoring, ventilation

DOI: 10.3233/PIC-13047

Citation: Journal of Pediatric Intensive Care, vol. 2, no. 1, pp. 39-44, 2013

Authors: Proulx, François

Article Type: Book Review

DOI: 10.3233/PIC-13048

Citation: Journal of Pediatric Intensive Care, vol. 2, no. 1, pp. 45-45, 2013

Authors: Pons-Ódena, Martí | de la Fuente, Alexandre Escribá | Lasaosa, Francisco José Cambra | Matute, Susana Segura | Rico, Antonio Palomeque | Modesto, Vicent

Article Type: Correction

DOI: 10.3233/PIC-13040

Citation: Journal of Pediatric Intensive Care, vol. 2, no. 1, pp. 47-47, 2013