Air Bolus Research Articles

The effect of budesonide delivered by high-frequency oscillatory ventilation on acute inflammatory response in severe lung injury in adult rabbits.

The inflammation present in acute respiratory distress syndrome (ARDS) and thereby associated injury to the alveolar-capillary membrane and pulmonary surfactant can potentiate respiratory failure. Even considering the high mortality rate of severe ARDS, glucocorticoids appear to be a reasonable treatment option along with an appropriate route of delivery to the distal lung. This study aimed to investigate the effect of budesonide therapy delivered intratracheally by high-frequency oscillatory ventilation (HFOV) on lung function and inflammation in severe ARDS. Adult New Zealand rabbits with respiratory failure (P/F<13.3 kPa) induced by intratracheal instillation of hydrochloric acid (HCl, 3 ml/kg, pH 1.5) followed by high tidal ventilation (VT 20 ml/kg) to mimic ventilator-induced lung injury (VILI) were treated with intratracheal bolus of budesonide (0.25 mg/kg, Pulmicort) delivered by HFOV (frequency 8 Hz, MAP 1 kPa, deltaP 0.9 kPa). Saline instead of HCl without VILI with HFOV delivered air bolus instead of therapy served as healthy control. All animals were subjected to lung-protective ventilation for 4 h, and respiratory parameters were monitored regularly. Postmortem, lung injury, wet-to-dry weight ratio, leukocyte shifts, and levels of cytokines in plasma and lung were evaluated. Budesonide therapy improved the lung function (P/F ratio, oxygenation index, and compliance), decreased the cytokine levels, reduced lung edema and neutrophils influx into the lung, and improved lung architecture in interstitial congestion, hyaline membrane, and atelectasis formation compared to untreated animals. This study indicates that HFOV delivered budesonide effectively ameliorated respiratory function, and attenuated acid-induced lung injury in a rabbit model of severe ARDS.

Speech rehabilitation after total laryngectomy with voice prostheses: phonatory results

The approaches for voice rehabilitation after laryngectomy vary significantly, as they can be classified into natural and device-aided (external and surgical). The techniques differ in degree of accessibility, success and vocal results. Until the introduction of surgical methods, esophageal speech was the mainstay of rehabilitation. It is associated with long training period with questionable success. The electrolarynx, which in our country is still traditionally accepted as the main method of voice rehabilitation after laryngectomy, generates speech with a low degree of intelligibility and mechanical sound. The implantation of a voice prosthesis in a surgically shaped tracheoesophageal fistula is currently accepted as the gold standard. The aim of the study was phoniatric analysis of voice production in alaryngeal speech after tracheo-oesophageal puncture and implantation of a voice prosthesis. The characteristics of tracheoesophageal and oesophageal speech are compared. The obtained results show that the voice production after implantation of a voice prosthesis significantly exceeds the oesophageal voice in terms of average duration of phonation with one air bolus, number of words uttered with one bolus, and the pace and expressiveness of speech.

Challenges of de-implementing feeding tube auscultation: A qualitative study.

This qualitative study explored de-implementation of feeding tube auscultation practice in adult patients by critical care nurses. Despite years of evidence suggesting inaccuracy and harm, auscultation (air bolus method) continues to be used by the majority of critical care nurses to verify small-bore feeding tube placement in adults. This descriptive qualitative study used thematic analysis with telephone interview data. Fourteen critical care nurses from four stratified groups within the United States (by hospital type and auscultation practice) participated in telephone interviews. Two major themes of individual influence and organizational leadership emerged from the data. Categories identified key components required for auscultation de-implementation. Nurses feel obligated to follow hospital policies and expressed less accountability for their own practice. Organizational leadership involvement is recommended to facilitate de-implementation of this tradition-based, low-value practice and mitigate harm events.

Validation of sonographic assistance for placement of a nasogastric tube in pediatric patients.

Enteral access via nasogastric tube (NGT) placement can be essential in the provision of care in pediatric patients. Methods exist to confirm correct placement with success rates between 80% and 85%. Radiographic confirmation remains the "gold-standard," however; it exposes patients to ionizing radiation and fails to provide "real-time" information. In this study, we determined the feasibility of using sonography to assist in the placement of NGT insertions in pediatric patients that have difficulty cooperating. Thirty patients requiring NGT placement were stratified into three age groups. Upon NGT insertion, transverse and longitudinal ultrasound images were acquired to visualize tube progression through the esophagus. Subsequently, a focused ultrasonographic exam of the gastric antrum and body were performed. If amenable, an air bolus (1 mL/kg) was injected in the stomach if the NGT was not directly visualized. Following intubation, standard guidelines for NGT position confirmation were performed. The NGT was visualized in all esophageal views and 52% of gastric views. Subgroup analysis showed that successful visualization of tube placement in the stomach ranged from 40% (7-18 years) to 70% (3-6 years). Eighty percentage of air boluses injected were visualized. The use of ultrasonography may assist NGT placement in pediatric patients and reduce the incidence of suboptimal placement during insertion. We demonstrated successful NGT visualization through the esophagus regardless of age. NGT visualization in the stomach was challenging; however, injection of an air bolus may improve visualization. Further studies are required to improve the success rate of obtaining gastric views of the NGT.

In vitro evaluation of Capiox FX05 and RX05 oxygenators in neonatal cardiopulmonary bypass circuits with varying venous reservoir and vacuum-assisted venous drainage levels.

The purpose of this study was to evaluate the hemodynamic properties and microemboli capture associated with different vacuum-assisted venous drainage (VAVD) vacuum levels and venous reservoir levels in a neonatal cardiopulmonary bypass circuit. Trials were conducted in 2 parallel circuits to compare the performance of Capiox Baby RX05 oxygenator with separate AF02 arterial filter to Capiox FX05 oxygenator with integrated arterial filter. Arterial cannula flow rate to the patient was held at 500mL/min and temperature maintained at 32°C, while VAVD vacuum levels (0mm Hg, -15mm Hg, -30mm Hg, -45mm Hg, -60mm Hg) and venous reservoir levels (50mL, 200mL) were evaluated in both oxygenators. Hemodynamic parameters measuring flow, pressure, and total hemodynamic energy were made in real time using a custom-made data acquisition system and Labview software. Nearly 10cc bolus of air was injected into the venous line and gaseous microemboli detected using an Emboli Detection and Classification Quantifier. Diverted blood flow via the arterial filter's purge line and mean pressures increased with increasing VAVD levels (P<0.01). Mean pressures were lower with lower venous reservoir levels and were greater in RX05 groups compared to FX05 (P<0.01). Microemboli detected at the preoxygenator site increased with higher VAVD vacuum levels and lower venous reservoir levels (P<0.01). The amount of microemboli captured by the FX05 oxygenator with integrated arterial filter was greater than by the RX05 oxygenator alone, although both oxygenators were able to clear microemboli before reaching the pseudo-patient.

A Resuscitation Option for Upper Airway Occlusion Based on Bolus Transtracheal Lung Inflation.

BackgroundAcute laryngospasm sufficient to cause obstructive apnea is a medical emergency that can be difficult to manage within the very short time available for establishing an airway. We have presented substantial evidence that laryngospasm‐based obstructive apnea is the cause of sudden death in epilepsy, and airway management is particularly challenging during seizure activity.ObjectiveWe sought to determine if the transtracheal delivery of a bolus of oxygen or room air below the level of an obstruction to inflate the lungs could be an effective method to prolong the time available for responders seeking to establish a stable airway, and, if so, what could be learned about optimization of delivery parameters from a rat model.MethodsRats were fitted with a t‐shaped tracheal tube for controlling access to air and for measuring airway pressures. After respiratory arrest from simulated laryngospasm, bolus transtracheal lung inflation with a volume of gas equivalent to half the vital capacity was delivered to the closed respiratory system as the only resuscitation step.ResultsBolus lung inflation was sufficient for resuscitation, improving cardiac function and re‐establishing adequate oxygen status to support life. Inflation steps could be repeated and survival times were approximately 3 times that of non‐inflated lungs.ConclusionThe properties and consequences of bolus lung inflation are described as a foundation for procedures or devices that can be useful in cases of severe laryngospasm and other cases of upper airway obstruction.Level of Evidence3

Loss of Surfacten® during bolus administration with a feeding catheter.

Surfactant replacement therapy is widely used for treating neonatal respiratory distress syndrome, but insufficient evidence is available on the use of Surfacten® (S-TA). This study investigated the inadvertent loss of S-TA during instillation via feeding catheters with different bore sizes. In this bench-based study, we measured the weight of syringes and tubes before and after surfactant treatment using a high-accuracy balance, and determined the amount of S-TA lost in tubes. We injected 120mg of S-TA suspended in 4 or 3mL into tubes followed with or without air boluses. Experiments were performed in triplicate. Percent weight loss of S-TA in each tube was calculated with or without air boluses. Percent weight loss of S-TA was significantly higher in larger-bore tubes (P<0.01, overall ANOVA), and was significantly lower after air bolus flushing in 3 Fr, 4 Fr, and 5 Fr tubes (P<0.005, respectively). The 3 mL S-TA suspensions had a significantly higher percent loss than the 4 mL S-TA suspensions when using 4 Fr and 5 Fr tubes, and the 5 Fr closed system (P<0.05, respectively). Routine air bolus flushing effectively reduces S-TA loss in tubes. The 3mL S-TA suspensions appear to be more susceptible to inadvertent S-TA loss during instillation. Therefore, caution is warranted for this procedure.

Effects of Purge-Flow Rate on Microbubble Capture in Radial Arterial-Line Filters

The process of microbubble filtration from blood is complex and highly dependent on the forces of flow and buoyancy. To protect the patient from air emboli, arterial-line filters commonly use a micropore screen, a large volume housing with purpose-built shape, and a purge port to trap, separate, and remove circulating microbubbles. Although it has been proposed that an insufficient buoyancy force renders the purge port ineffective at removing microbubbles smaller than 500 μm, this research attempts to investigate the purge flow of an arterial-line filter to better understand the microbubble removal function in a typical radial filter design. As its primary objective, the study aims to determine the effect of purge-flow rate on bubble capture using air bolus injections from a syringe pump with 22-gauge needle and Doppler ultrasound bubble detection. The measureable bubble size generated in the test circuit ranged between 30 and 500 μm, while purge flow was varied between .1 and .5 L/min for testing. Statistical analysis of the test data was handled using a repeated measures design with significance set atp&lt; .05 level. Outcomes demonstrated that higher purge flows yielded higher bubble counts, but the effect of purge-flow rate on bubble capture decreased as bubble size increased. Results also showed that purge flow from the test filter was capable of capturing all bubble sizes being generated over the entire flow range tested, and confirms utility of the purge port in removing microbubbles smaller than 500 μm. By analyzing bubble counts in the purge flow of a typical radial-filter design, this study demonstrates that currently available micropore filter technology is capable of removing the size range of bubbles that commonly pass through modern pump-oxygenator systems and should continue to be considered during extracorporeal circulation as a measure to improve patient safety.

Removal of Gross Air Embolization from Cardiopulmonary Bypass Circuits with Integrated Arterial Line Filters: A Comparison of Circuit Designs

Advances in technology, the desire to minimize blood product transfusions, and concerns relating to inflammatory mediators have lead many practitioners and manufacturers to minimize cardiopulmonary bypass (CBP) circuit designs. The oxygenator and arterial line filter (ALF) have been integrated into one device as a method of attaining a reduction in prime volume and surface area. The instructions for use of a currently available oxygenator with integrated ALF recommends incorporating a recirculation line distal to the oxygenator. However, according to an unscientific survey, 70% of respondents utilize CPB circuits incorporating integrated ALFs without a path of recirculation distal to the oxygenator outlet. Considering this circuit design, the ability to quickly remove a gross air bolus in the blood path distal to the oxygenator may be compromised. This in vitro study was designed to determine if the time required to remove a gross air bolus from a CPB circuit without a path of recirculation distal to the oxygenator will be significantly longer than that of a circuit with a path of recirculation distal to the oxygenator. A significant difference was found in the mean time required to remove a gross air bolus between the circuit designs (p = .0003). Additionally, There was found to be a statistically significant difference in the mean time required to remove a gross air bolus between Trial 1 and Trials 4 (p = .015) and 5 (p =.014) irrespective of the circuit design. Under the parameters of this study, a recirculation line distal to an oxygenator with an integrated ALF significantly decreases the time it takes to remove an air bolus from the CPB circuit and may be safer for clinical use than the same circuit without a recirculation line.

Effects of Aging and Acid Reflux on Esophageal Motility

Introduction: It is generally thought that esophageal motility decreases with age, however a decrease in esophageal motility may also be caused by esophagitis. The aim of this study is to investigate the effects of aging and acid reflux on esophageal motility. Methods: 40 young (under 45) healthy subjects (HS) and 40 elderly (over 65) HS, with neither reflux symptoms nor reflux esophagitis (RE), and 40 elderly patients with mild RE (elderly RE), underwent esophageal high resolution manometry with a 21-lumen perfused assembly, which monitored pressure in the pharynx, the upper esophageal sphincter, the esophageal body, the lower esophageal sphincter (LES) and the proximal stomach. An infusion port, located 18cm above the distal side hole, was used to inject air and expiratory basal LES pressure was referenced to end expiratory intragastric pressure. Primary peristalsis was tested with 5ml water swallows, each swallow separated by a 30 second interval and the process repeated 10 times. Secondary peristalsis was triggered by esophageal distention, using a 20ml bolus of air, which was injected rapidly, by hand, into the middle esophagus. After 20 seconds each stimulus was followed by a dry swallow to clear any of the residual air and then repeated 5 times. Results: There was no difference in the LES pressure and also in the success rate of primary peristalsis between young and elderly HS or between elderly HS and RE. There was no difference in the distal contractile integral (DCI) of primary peristalsis and secondary peristalsis between the young and elderly HS, but in the elderly RE, it was significantly lower than in the elderly HS. There was no difference in the success rate of secondary peristalsis between elderly HS and RE, but in elderly HS it was significantly lower than in young HS. Conclusion: Aging may cause a decrease in the success rate of secondary peristalsis, and acid reflux itself may cause a decrease of the DCI in primary and secondary peristalsis.

Secondary Esophageal Peristalsis in Patients With GERD

Introduction: We have reported that the triggering of secondary peristalsis is defective in patients with NERD but the difference in the triggering of secondary peristalsis between patients with NERD and patients with RE is poorly understood, therefore the aim of this study is to evaluate the difference in esophageal motility between patients with NERD and RE. Methods: 20 patients with NERD, who also had gastroesophageal reflux symptoms which occurred more than twice per week, were compared with 20 patients with mild RE of LA-grade A or B, 20 patients with severe RE of LA-grade C and 20 healthy subjects (HS). Manometry was carried out with a perfused assembly, which incorporated side holes in the pharynx, the UES, the esophagus, and 10 side holes (1cm apart), which straddled the distal esophagus, the esophagogastric junction and the proximal stomach. An infusion port, located 18cm above the distal side hole, was used to inject air. Secondary peristalsis was triggered by esophageal distention, using a 20ml bolus of air, injected rapidly, by hand, into the middle esophagus. After 20 seconds each stimulus was followed by a dry swallow to clear any residual air and then each stimulus was repeated 5 times. Results: The success rate of secondary peristalsis in patients with severe RE (20 % (0.0-40.0)) was significantly lower than in patients with mild RE (40.0 (20.0-80.0)) and HS (80.0 (70.0-90.0)) but there was no difference in the success rate of secondary peristalsis between patients with severe RE and patients with NERD (20 (0.0-40.0)). The success rate of secondary peristalsis in patients with mild RE was significantly lower than that of HS, but was significantly higher than that of patients with NERD. The success rate of secondary peristalsis in patients with NERD was significantly lower than that of HS. The amplitude of secondary peristalsis in patients with severe RE (25.0 mmHg (14.0-40.0)) was significantly lower than in patients with mild RE (41.0 (27.0-60.0)), patients with NERD (52.5 (40.0-70.0)) and HS (46.0 (33.0-63.0)). The amplitude of secondary peristalsis in patients with mild RE was significantly lower than that of NERD. Conclusion: Defective secondary peristalsis was observed in patients with NERD and those with RE and the success rate of secondary peristalsis significantly decreased in accordance with the severity of RE. The degree of defective secondary peristalsis in patients with NERD was similar to that of patients with severe RE.

Rapid air infusion into the oesophagus: Motor response in patients with achalasia and nonobstructive dysphagia assessed with high-resolution manometry.

Achalasia is a neurodegenerative disorder of the oesophagus. Alteration of motor activity induced by oesophageal distension has not been explored. To investigate this function, using high-resolution Manometry. This study enrolled 15 healthy subjects, 15 nonobstructive dysphagia (NOD), and 18 achalasia patients successfully treated with pneumatic dilation (six with restored peristalsis). The three groups underwent five rapid (<1 s) intraoesophageal infusions of 20-ml air boluses, followed by eight 5-ml water swallows. WHEREAS THE RESPONSE RATE TO WATER SWALLOWS WAS SIMILAR IN THE THREE GROUPS, AIR INFUSION INDUCED A LOWER RESPONSE RATE IN ACHALASIA (MEDIAN, INTERQUARTILE RANGE: 70%, 40-100%) and, to a lesser extent, in NOD patients (100%, 60-100%) than in healthy subjects (100%, 100-100%; p < 0.001 and p = 0.06, respectively). However, the response rate was highly variable in achalasia patients irrespective of presence of peristalsis. Furthermore, the strength of motor response to air infusion when compared to water swallows was diminished in achalasia patients but not in healthy subjects and NOD. Motor response to rapid air infusion was variably impaired in achalasia. The role of this alteration in the long-term outcome deserves evaluation.

P.10.16 SENSITIVITY AND SPECIFICITY OF THE PANEL TEST “GASTROPANEL” FOR THE NON INVASIVE DIAGNOSIS OF ATROPHIC GASTRITIS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background and aim: Cold water affects both swallow induced and spontaneous motor activity in healthy subjects, but not in achalasia patients. It has been hypothesized that this lack of effect is due to impairment of sensory neural pathways. Our aim was to investigate perception of rapid air infusion before and after oesophageal cooling in patients with achalasia compared to healthy subjects. Material and methods: Twenty-one healthy subjects, 7 men, 25 (median); 22–31 yrs (range), as control group, and 15 consecutive achalasia patients after successful pneumatic dilation, 8 men, 47; 29–80 yrs were enrolled. Diameter of the oesophageal body was 2.1 (median); 1.1–3.0 cm (range) in the patients. All subjects and patients underwent 5 rapid (<1 sec) intraoesophageal infusions of 20 ml air boluses al 30 cm from the nares through a naso oesophageal catheter in basal condition and after swallowing 200 ml water in ≤30 s both at room temperature and at 4°C in randomized order. Oesophageal aspiration was performed at predetermined intervals to ensure a negative intraoesophageal pressure. Oesophageal perception after air infusion in the three experimental conditions was evaluated using a visual analogue scale (1 corresponding to a minimal air sensation and 10 corresponding to an air vortex in the oesophagus). Non parametric statistics was used. Results: Ten out of the 21 (48%) healthy subjects increased their perception of air infusion after cooling whereas only 4 out of the 15 (27%) achalasia patients did. See table for perception scores [median (IQ range)].

Main individual and product characteristics influencing in-mouth flavour release during eating masticated food products with different textures: Mechanistic modelling and experimental validation

A mechanistic model predicting flavour release during oral processing of masticated foods was developed. The description of main physiological steps (product mastication and swallowing) and physical mechanisms (mass transfer, product breakdown and dissolution) occurring while eating allowed satisfactory simulation of in vivo release profiles of ethyl propanoate and 2-nonanone, measured by Atmospheric Pressure Chemical Ionization Mass Spectrometry on ten representative subjects during the consumption of four cheeses with different textures. Model sensitivity analysis showed that the main parameters affecting release intensity were the product dissolution rate in the mouth, the mass transfer coefficient in the bolus, the air–bolus contact area in the mouth and the respiratory frequency. Parameters furthermore affecting release dynamics were the mastication phase duration, the velopharynx opening and the rate of saliva incorporation into the bolus. Specific retention of 2-nonanone on mucosa was assumed to explain aroma release kinetics and confirmed when gaseous samples were consumed.

Vented Chest Seals for Prevention of Tension Pneumothorax in a Communicating Pneumothorax

BackgroundTension pneumothorax accounts for 3%–4% of combat casualties and 10% of civilian chest trauma. Air entering a wound via a communicating pneumothorax rather than by the trachea can result in respiratory arrest and death. In such cases, the Committee on Tactical Combat Casualty Care advocates the use of unvented chest seals to prevent respiratory compromise. ObjectiveA comparison of three commercially available vented chest seals was undertaken to evaluate the efficacy of tension pneumothorax prevention after seal application. MethodsA surgical thoracostomy was created and sealed by placing a shortened 10-mL syringe barrel (with plunger in place) into the wound. Tension pneumothorax was achieved via air introduction through a Cordis to a maximum volume of 50 mL/kg. A 20% drop in mean arterial pressure or a 20% increase in heart rate confirmed hemodynamic compromise. After evacuation, one of three vented chest seals (HyFin®, n = 8; Sentinel®, n = 8, SAM®, n = 8) was applied. Air was injected to a maximum of 50 mL/kg twice, followed by a 10% autologous blood infusion, and finally, a third 50 mL/kg air bolus. Survivors completed all three interventions, and a 15-min recovery period. ResultsThe introduction of 29.0 (±11.5) mL/kg of air resulted in tension physiology. All three seals effectively evacuated air and blood. Hemodynamic compromise failed to develop with a chest seal in place. ConclusionsHyFin®, SAM®, and Sentinel® vented chest seals are equally effective in evacuating blood and air in a communicating pneumothorax model. All three prevented tension pneumothorax formation after penetrating thoracic trauma.

Hyperbaric Oxygen Does Not Improve Cerebral Function When Started 2 or 4 Hours After Cerebral Arterial Gas Embolism in Swine*

Hyperbaric oxygenation is the accepted treatment for cerebral arterial gas embolism. Although earlier start of hyperbaric oxygenation is associated with better outcome, it is unknown how much delay can be tolerated before start of hyperbaric oxygenation. This study investigates the effect of hyperbaric oxygenation on cerebral function in swine when initiated 2 or 4 hours after cerebral arterial gas embolism. Prospective interventional animal study. Surgical laboratory and hyperbaric chamber. Twenty-two Landrace pigs. Under general anesthesia, probes to measure intracranial pressure, brain oxygen tension (PbtO2), and brain microdialysis, and electrodes for electroencephalography were placed. The electroencephalogram (quantified using temporal brain symmetry index) was suppressed during 1 hour by repeated injection of air boluses through a catheter placed in the right ascending pharyngeal artery. Hyperbaric oxygenation was administered using U.S. Navy Treatment Table 6 after 2- or 4-hour delay. Control animals were maintained on an inspiratory oxygen fraction of 0.4. Intracranial pressure increased to a mean maximum of 19 mm Hg (SD, 4.5 mm Hg) due to the embolization procedure. Hyperbaric oxygenation significantly increased PbtO2 in both groups treated with hyperbaric oxygenation (mean maximum PbtO2, 390 torr; SD, 177 torr). There were no significant differences between groups with regard to temporal brain symmetry index (control vs 2-hr delay, p = 0.078; control vs 4-hr delay, p = 0.150), intracranial pressure, and microdialysis values. We did not observe an effect of hyperbaric oxygenation on cerebral function after a delay of 2 or 4 hours. The injury caused in our model could be too severe for a single session of hyperbaric oxygenation to be effective. Our study should not change current hyperbaric oxygenation strategies for cerebral arterial gas embolism, but further research is necessary to elucidate our results. Whether less severe injury benefits from hyperbaric oxygenation should be investigated in models using smaller amounts of air and clinical outcome measures.

Surfactant Inadvertent Loss Using Feeding Catheters or Endotracheal Tubes

Surfactant has been administered through endotracheal tubes and also under spontaneous breathing using feeding catheters. We asked if different tube diameters and temperature may affect the amount of surfactant effectively delivered to the lungs. Bench study using high-accuracy, legal balance and tube/catheters of different diameters. We injected 200 mg of poractant alfa into the tubes followed by air boluses. Experiments were performed in triplicate, both at room temperature and at 37°C. Surfactant and phospholipid remaining in the tube were calculated. Surfactant lost into thin catheters (11 ± 0.4%) was more than that in endotracheal tubes (2-mm diameter: 3.6 ± 1.4%; 2.5-mm diameter: 3.7 ± 0.2%; 3-mm diameter: 5.2 ± 0.4%; p < 0.001 at post hoc test in each comparison against the thin catheter). Similar findings were found at 37°C (2-mm tube: 3.4 ± 0.4%; 2.5-mm tube: 3.8 ± 0.2%; 3-mm tube: 3.6 ± 0.4%; feeding tube: 11.5 ± 0.6%; p < 0.001 as above). In terms of lost phospholipids, 23 ± 0.8 mg were lost in the feeding tubes; 7.2 ± 2.9 mg (2-mm diameter), 7.4 ± 0.4 mg (2.5-mm diameter), and 10.3 ± 0.9 mg (3-mm diameter) of phospholipids remained in endotracheal tubes (p < 0.001 in each comparison against the feeding tube). Surfactant loss using thin catheters is around two to three times higher than using common endotracheal tubes; on average, 20 mg of phospholipids (11% of the administered dose) are lost. These data may be useful to refine surfactant dosing.

Small-airways deposition of dornase alfa in children with asthma and persistent airway obstruction

Small-airways deposition of dornase alfa in children with asthma and persistent airway obstruction

Topical application of phosphatidyl-inositol-3,5-bisphosphate for acute lung injury in neonatal swine.

Hypoxemic respiratory failure of the neonatal organism involves increased acid sphingomyelinase (aSMase) activity and production of ceramide, a second messenger of a pro-inflammatory pathway that promotes increased vascular permeability, surfactant alterations and alveolar epithelial apoptosis. We comparatively assessed the benefits of topical aSMase inhibition by either imipramine (Imi) or phosphatidylinositol-3,5-bisphosphate (PIP2) when administered into the airways together with surfactant (S) for fortification. In this translational study, a triple-hit acute lung injury model was used that entails repeated airway lavage, injurious ventilation and tracheal lipopolysaccharide instillation in newborn piglets subject to mechanical ventilation for 72 hrs. After randomization, we administered an air bolus (control), S, S+Imi, or S+PIP2. Only in the latter two groups we observed significantly improved oxygenation and ventilation, dynamic compliance and pulmonary oedema. S+Imi caused systemic aSMase suppression and ceramide reduction, whereas the S+PIP2 effect remained compartmentalized in the airways because of the molecule's bulky structure. The surfactant surface tensions improved by S+Imi and S+PIP2 interventions, but only to a minor extent by S alone. S+PIP2 inhibited the migration of monocyte-derived macrophages and granulocytes into airways by the reduction of CD14/CD18 expression on cell membranes and the expression of epidermal growth factors (amphiregulin and TGF-β1) and interleukin-6 as pro-fibrotic factors. Finally we observed reduced alveolar epithelial apoptosis, which was most apparent in S+PIP2 lungs. Exogenous surfactant “fortified” by PIP2, a naturally occurring surfactant component, improves lung function by topical suppression of aSMase, providing a potential treatment concept for neonates with hypoxemic respiratory failure.

Evaluation of four pediatric cardiopulmonary bypass circuits in terms of perfusion quality and capturing gaseous microemboli

This study compared four pediatric cardiopulmonary bypass (CPB) circuits with four different hollow-fiber membrane oxygenators and their specific reservoirs, Capiox RX15, Quadrox-i pediatric, Quadrox-i pediatric with integrated arterial filter (IAF) and KIDS D101, in a simulated CPB circuit identical to that used in the clinical setting at our institution to test their ability to maintain hemodynamic properties, remove gaseous microemboli (GME), and to test the amount of blood "stolen" by the arterial filter purge line. The circuit was first primed with Ringer's Lactate solution, then red blood cells were added and the hematocrit was maintained at 30%. A 5-cc bolus of air was injected just proximal to the venous reservoir over a thirty-second interval and GME were monitored using an Emboli Detection and Classification quantifier. Transducers were placed at pre-oxygenator, post-oxygenator and distal arterial line (post-filter) positions. Flow probes were also placed both pre and post filter. The injections were made at three flow rates, hypothermic and normothermic temperatures, and with the purge line in both the opened and closed positions. Six injections were done at each of the 12 experimental conditions. Results demonstrated that GME in the arterial line increased with increasing temperature and flow rate. The Capiox RX15 had the least GME in the arterial line at all experimental conditions. The KIDS D101 had the largest pressure drop and the lowest retention of hemodynamic energy, while the Capiox had the lowest pressure drop. All of the oxygenators had a similar amount of "stolen" blood flow and it was consistently under 10% of the total flow reaching the patient.