Air Bolus Research Articles

New insights into mechanism of Eustachian tube ventilation based on cine computed tomography images

There is debate concerning the mechanism of Eustachian tube (ET) ventilation. While a mechanism of complete opening has been advocated previously, sequential contraction of the levator veli palatini and medial pterygoid muscles followed by the tensor veli palatini and lateral pterygoid muscles may produce a transient sequential opening mechanism, allowing an air bolus to traverse the ET. This may explain confusion surrounding sonotubometry reports that not every swallow leads to sound passage in normal subjects. We hypothesize that the ET may not need to open completely when ventilating the middle ear; rather, a discrete air bolus can pass through it. Five normal and five disordered subjects underwent low-radiation dose cine computed tomography (CT) scans of the ET. Sixteen contiguous 2.5 mm slice locations were chosen through a 4 cm area in the nasopharynx that were parallel to and encompassed the entire ET. Twelve images were acquired at each slice over 4.8 s during swallowing and other tasks. Serial images were analyzed. An air bolus was observed passing through the ET in the normal subjects, but not the subject with ET dysfunction. Medial and lateral pterygoid contractions were also observed. A new hypothetical mechanism of transient sequential ET ventilation is presented. This is not a definitive conclusion, as the number of scans taken and maneuvers used was limited. Improved understanding of ET ventilation may facilitate management of middle ear disease as treatment evolves from ventilatory tube placement to ET manipulation.

Evaluation of Capiox FX05 Oxygenator With an Integrated Arterial Filter on Trapping Gaseous Microemboli and Pressure Drop With Open and Closed Purge Line

Gaseous microemboli (GME) remain a challenge for cardiopulmonary bypass (CPB) because there is a positive correlation between microemboli exposure during CPB and postoperative neurological injury. Thus, minimizing the number of GME delivered to pediatric patients undergoing CPB procedures would lead to better clinical outcomes. In this study, we used a simulated CPB model to evaluate the effectiveness of capturing GME and the degree of membrane pressure drop for a new membrane oxygenator, Capiox Baby FX05 (Terumo Corporation,Tokyo, Japan), which has an integrated arterial filter with open and closed purge line.We used identical components in this study as our clinical CPB circuit. Three emboli detection and classification quantifier transducers were placed at prepump, preoxygenator, and postoxygenator sites in the circuit.Two flow probes as well as three pressure transducers were placed upstream and downstream of the oxygenator. The system was primed with human blood titrated to 30% hematocrit with Lactated Ringer’s solution.A bolus of air (1 mL) was injected in the prepump site under nonpulsatile perfusion mode at three flow rates (500,750, and 1000 mL/min) and with the purge line either open or closed. Six trials were performed for each unique set-up for a total of 36 trials.All trials were conducted at 35°C. The circuit pressure was kept constant at 100 mm Hg. Both the size and quantity of microemboli detected at postoxygenator site were recorded for 5 min postair injection. It was found that total counts of GME were significantly reduced with the purge line open when compared to keeping the purge line closed (P < 0.0001 at 1000 mL/min). At all flow rates, most of the GME were under 20 microns in size. In terms of microemboli greater than 40 microns, the counts were significantly higher with the purge line closed compared to keeping the purge line open at flow rates of 750 mL/min and 1000 mL/min (P < 0.01). At all flow rates,there is a tiny difference of less than 1 mmHg in membrane pressure drop between keeping the purge line open and closed, which is due to the small arteriovenous (A-V) shunt(P < 0.001). These results suggest that the integrated arterial filter of the Capiox FX05 oxygenator significantly improves the capturing of GME but has little impact on membrane pressure drop.

Evaluation of HL‐20 Roller Pump and Rotaflow Centrifugal Pump on Perfusion Quality and Gaseous Microemboli Delivery

The purpose of this study was to compare the HL-20 roller pump (Jostra USA, Austin, TX, USA) and Rotaflow centrifugal pump (Jostra USA) on hemodynamic energy production and gaseous microemboli (GME) delivery in a simulated neonatal cardiopulmonary bypass (CPB) circuit under nonpulsatile perfusion. This study employed a simulated model of the pediatric CPB including a Jostra HL-20 heart-lung machine (or a Rotaflow centrifugal pump), a Capiox BabyRX05 oxygenator (Terumo Corporation, Tokyo, Japan), a Capiox pediatric arterial filter (Terumo Corporation), and ¼-inch tubing. The total volume of the experimental system was 700mL (500mL for the circuit and 200mL for the pseudo neonatal patient). The hematocrit was maintained at 30% using human blood. At the beginning of each trial, a 5mL bolus of air was injected into the venous line. Both GME data and pressure values were recorded at postpump and postoxygenator sites. All the experiments were conducted under nonpulsatile perfusion at three flow rates (500, 750, and 1000mL/min) and three blood temperatures (35, 30, and 25°C). As n=6 for each setup, a total of 108 trials were done. The total number of GME increased as temperature decreased from 35°C to 25°C in the trials using the HL-20 roller pump while the opposite effect occurred when using the Rotaflow centrifugal pump. At a given temperature, total GME counts increased with increasing flow rates for both pumps. Results indicated the Rotaflow centrifugal pump delivered significantly fewer microemboli compared to the HL-20 roller pump, especially under high flow rates. Less than 10% of total microemboli were larger than 40µm in size and the majority of GME were in the 0-20µm class in all trials. Postpump total hemodynamic energy (THE) increased with increasing flow rates and decreasing temperatures in both circuits using these two pumps. The HL-20 roller pump delivered more THE than the Rotaflow centrifugal pump at all tested flow rates and temperature conditions. Results suggest the HL-20 roller pump delivers more GME than the Rotaflow centrifugal pump but produces more hemodynamic energy under nonpulsatile perfusion mode.

Evaluation of the Quadrox-I neonatal oxygenator with an integrated arterial filter

Cardiopulmonary bypass (CPB) can be a potential cause of morbidity in patients for several reasons, including significantly higher gaseous microemboli (GME) formation than extracorporeal life support (ECLS) and physiological circulation, diverted blood flow from the patient via an open purge line of the arterial filter, and pressure drop across the oxygenator that is used in the circuit. Using a combined oxygenator and arterial filter may minimize these harmful factors and can effectively reduce the chances for postoperative morbidity. This study investigated the new QUADROX-i Neonatal Oxygenator (D-72145, Maquet, Hirrlingen, Germany) with an integrated arterial filter in terms of the hemodynamic properties and ability to clear GME in response to hypothermic versus normothermic conditions, open versus closed arterial filter purge line, and varying flow rates in a simulated CPB circuit identical to that of the clinical setting. A flow probe, pressure transducer, and Emboli Detection and Classification (EDAC) quantifier transducer were placed upstream and downstream to the oxygenator to measure changes in each parameter. The circuit was primed with fresh human blood with an hematocrit (Hct) of 26% diluted with Ringer's lactate solution. Five milliliters of air were injected proximal to the venous cardiotomy reservoir, under non-pulsatile perfusion, with flow rates of 500 ml/min, 750 ml/min, and 1000 ml/min. A total of 8 air bolus injections were made at each individual set of conditions for a total of 96 injections. Results showed that the QUADROX-i Neonatal Oxygenator with an integrated filter has excellent hemodynamic properties with extremely low pressure drops and blood flow diverted from the patient, as well as high rates of GME capturing. The arterial filter purge line has a significant effect on the degree of blood flow diverted from the patient (p < 0.001), but does not affect pressure drop across the oxygenator.

Pre-clinical laboratory evaluation of the new ‘AF’ arterial line filter range

The presence of emboli was recognised relatively early in the history of open heart surgery. The emboli produced during cardiopulmonary bypass have the predisposition to distribute into, and ultimately obstruct, microvessels of all tissues. The Sorin Group has recently developed a new range of arterial line filters. Before the Sorin AF range of filters was released for pre-launch clinical trials, our group performed in vitro laboratory testing of the AF range against a selection of commercially available filters on the global market. The Sorin AF620 and AF640 demonstrate both the smallest prime volume and smallest surface contact area (92ml and 290 cm(2), respectively).The results of the GME Handling Efficiency experiments ranged by 39.6%, from 95.9% to 56.3%. In terms of an air bolus handling, the results of the Limit Bolus experiment ranged by 97 ml, from 147.5 ml down to 50 ml. The pressure drop across all the filters was measured under steady state experimental conditions. All of the above investigations were considered against surface area and prime volume. It is clear from the results that some commercially available arterial line filters perform better than others, not only in overall performance, but also with regard to individual characteristics. Evaluating arterial line filters for hospital-specific use has to balance pressure drop, surface area, micro air handling, prime volume and gross air handling; all points need to be considered. In the AF620 and AF640, Sorin boast that they are the two smallest prime and smallest surface area filters commercially available on the global market. The Sorin AF filter range performs well in all of the areas we investigated and will be a competitive option for centres, irrespective of which characteristics they use to evaluate and select their arterial line filter.

In vitro testing of tympanostomy tube occlusion

Objective Tympanostomy tubes (TTs) are commonly rendered nonfunctional by mucus plug formation. The purpose of this study was to determine whether an in vitro model could be developed to assess TT plug formation with results consistent with human trials. Study Design An ear chamber was designed to mimic middle ear air and mucus flow conditions in post-TT otorrhea. TT occlusion was tested and correlated to published in vivo results. Methods TTs that had previously been studied in vivo (Goode “T” and Reuter Bobbin collar buttons) were placed in the model chamber. Pooled, homogenized human middle ear mucus and an analog, egg white, were delivered at 80 μL per hour through the TTs. An air bolus was delivered every two minutes to simulate swallowing. Chamber pressure was monitored over 2.5 hours. Occlusion was determined by a pressure peak and visual confirmation. Results Obstruction was found in 60 percent of the Reuter Bobbin and 40 percent of the Goode TTs using the mucus analog. These results are similar to those reported from previous in vivo studies. No plugging was reported for either TT using homogenized human ear mucus. Conclusions The in vitro TT chamber simulates the in vivo environment and yields results consistent with in vivo observations. This model system may allow for rapid prototyping and evaluation of new TTs that may be less vulnerable to occlusion.

Technical limitations in detection of gastroesophageal reflux in neonates.

Characterize the incidence and possible etiologies of acid reflux events detected by pH and not identified by multiple intraluminal impedance (MII) monitoring. Acid reflux events detected by pH but not identified by MII (pH-only) were documented in 80 preterm and 39 term infants. Reasons for failure of MII to detect these events were classified as failure to meet MII scoring criteria, presence of an air bolus, technical artifact, and no change in impedance. Events with no change in impedance were stratified to low impedance throughout the study (possible esophageal inflammation), transient decrease in pre-event impedance (presence of refluxate), occurrence <30 seconds of a preceding event, and no explanation. A total of 2572 events were detected by pH, with 59% of events not identified by MII. A higher incidence of pH-only events occurred in preterm versus term infants (54 +/- 27% versus 42 +/- 23%, P = .025, respectively). Thirteen percent of pH-only events were missed due to MII scoring criteria, 12% due to technical artifact, 11% due to an air bolus, and 64% had no change in impedance. Of the 978 events with no change in impedance, 154 were associated with low impedance throughout the study, 430 with a transient decrease in pre-event impedance, and 175 were preceded by a reflux episode within 30 seconds. There was a high incidence of acid reflux events detected by pH but not identified by MII. This occurred more often in the least mature infants, and we speculate that delayed esophageal fluid clearance is the major underlying mechanism.

Selective NF-κB inhibition, but not dexamethasone, decreases acute lung injury in a newborn piglet airway inflammation model

Acute respiratory failure in neonates (e.g. ARDS, meconium aspiration pneumonitis, pneumonia) is characterized by an excessive inflammatory response, governing the migration of polymorpho-nuclear leukocytes (PMNLs) into lung tissue and causing consecutive impairment of gas exchange and lung function. Critical to this inflammatory response is the activation of nuclear factor-κB (NF-κB) that is required for transcription of the genes for many pro-inflammatory mediators. We asked whether the inhibition of NF-κB activity using either a selective inhibitor (IKK-NBD peptide) or dexamethasone would be more effective in decreasing NF-κB activity and chemokine expression in pulmonary cells. Changes in lung function were repeatedly assessed for 24 h following induction of acute respiratory failure and therapeutic intervention. We conducted a randomized, controlled, prospective animal study with mechanically ventilated newborn piglets which underwent repeated airway lavage (20 ± 2 [SEM]) to remove surfactant and to induce lung inflammation. Admixed to 100 mg kg −1 surfactant, piglets then received either IKK-NBD peptide (S+IKK), a selective inhibitor of NF-κB activation, its control peptide without intrinsic activity, dexamethasone (S+Dexa), its solvent aqua, or an air bolus only (all groups n = 8). After 24 h of mechanical ventilation, the following differences were measured: PaO 2/FiO 2 (S+IKK 230 ± 9 mmHg vs. S+Dexa 188 ± 14, p < 0.05); ventilation efficiency index (0.18 ± 0.01 [3800/(PIP-PEEP) *f *PaCO 2] vs. 0.14 ± 0.01, p < 0.05); extravascular lung water (24 ± 1 ml kg −1 vs. 29 ± 2, p < 0.05); PMNL in BAL fluid (112 ± 21 cells μl −1 vs. 208 ± 34, p < 0.05), IL-8 (351 ± 117 pg ml −1 vs. 491 ± 144, p = ns) and leukotriene B 4 (23 ± 7 pg ml −1 vs. 71 ± 11, p < 0.01) in BAL fluid. NF-κB activity in the nucleus of pulmonary cells differed by 32 ± 5% vs. 55 ± 3, p < 0.001. Differences between these two intervention groups were more pronounced in the second half of the observation period (hours 12–24). At 24 h of mechanical ventilation, inhibition of NF-κB activity by IKK-NBD peptide admixed to surfactant as a carrier caused improved gas exchange, lung function and reduced pulmonary inflammation, as evidenced by reduction in PMNL migration into lung tissue due to reduced nuclear NF-κB activity. We conclude that IKK-NBD admixture to surfactant in acute neonatal respiratory failure is superior to dexamethasone administration within the first 24 h.

Acute management of vascular air embolism

Vascular air embolism (VAE) is known since early nineteenth century. It is the entrainment of air or gas from operative field or other communications into the venous or arterial vasculature. Exact incidence of VAE is difficult to estimate. High risk surgeries for VAE are sitting position and posterior fossa neurosurgeries, cesarean section, laparoscopic, orthopedic, surgeries invasive procedures, pulmonary overpressure syndrome, and decompression syndrome. Risk factors for VAE are operative site 5 cm above the heart, creation of pressure gradient which will facilitate entry of air into the circulation, orogenital sex during pregnancy, rapid ascent in scuba (self contained underwater breathing apparatus) divers and barotrauma or chest trauma. Large bolus of air can lead to right ventricular air lock and immediate fatality. In up to 35% patient, the foramen ovale is patent which can cause paradoxical arterial air embolism. VAE affects cardiovascular, pulmonary and central nervous system. High index of clinical suspicion is must to diagnose VAE. The transesophgeal echocardiography is the most sensitive device which will detect smallest amount of air in the circulation. Treatment of VAE is to prevent further entrainment of air, reduce the volume of air entrained and haemodynamic support. Mortality of VAE ranges from 48 to 80%. VAE can be prevented significantly by proper positioning during surgery, optimal hydration, avoiding use of nitrous oxide, meticulous care during insertion, removal of central venous catheter, proper guidance, and training of scuba divers.

Entrapped air and normal saline in the pericardium after epicardial ablation

Ablation of recurrent idiopathic left bundle branch block inferior-axis ventricular tachycardia was performed in a 50-year-old patient. After unsuccessful ablation attempts with an irrigated-tip catheter from the left ventricle (LV) and an anterolateral branch of the coronary sinus at the site of earliest activation, epicardial access and map were obtained. Phrenic nerve stimulation could be induced at the earliest site at the epicardium. To prevent phrenic nerve capture, a stepwise bolus of air (250 mL total) was injected into the pericardial space to separate the epicardium from the nerve, but without success.

Malpositioning of a nasogastric tube: a pitfall in the emergency department

A 57-year-old man had a past history of diabetes mellitus controlled by oral hypoglycaemic agents. He was brought into the emergency department one day by paramedics after ingesting over 200 ml of synthetic pyrethroid insecticide (alpha-cypermethrin). The patient was vomiting and agitated; therefore, a nasogastric tube was immediately inserted in order to perform gastric lavage. Routine chest X-ray was also done before admission (Fig. 1). Fig. 1 Chest X-ray revealed nasogastric tube inserted into right main stem bronchus Placement of a nasogastric tube is indicated to decompress the stomach by aspiration of gastric contents, to introduce fluids and to assist in the clinical diagnosis of the ingested contents or gastric contents. Accidental misplacement of a nasogastric tube can occur in high-risk patients such as sedated patients, patients with weak cough reflex, endotracheally intubated patients and agitated patients [1]. Various methods to verify nasogastric tube placement in the stomach include the use of chest X-ray, aspiration of gastric content with the irrigating syringe, audible sounds of air entering the stomach while a 30 cc air bolus is injected with the syringe, and able to talk without coughing, choking or cyanosis. It is important to verify nasogastric tube placement in the stomach because the result of misplacement can be fatal such as aspiration pneumonitis or aspiration pneumonia.

Arterial Line Filters Ranked for Gaseous Micro-Emboli Separation Performance: An In Vitro Study

Arterial line filters (ALFs) are arguably the most important component in the cardiopulmonary bypass circuit to protect the patient from gaseous macro-and micro-emboli (GME) originating in the perfusion circuit. The GME separating ability of 10 ALFs was ranked according to seven performance criteria. Ten ALFs rated between 20 and 43 μm were evaluated for flow resistance, the count, size, and volume of GME passed after a 10-mL room air bolus, and the ability to separate a high-count, 10-to 200-μm flowing distribution of GME. The Luna Innovations EDAC™ emboli detector was used to size, count, and sort GME. Three test trials were conducted for 3 each of the 10 filters. Performance criteria were correlated by regression analysis, statistically compared using analysis of variance, or ranked using non-parametric tests. Significance was set at 0.05. Weighting all seven test parameters equally, the most effective ALFs were the Cobe 21 and Gish 25-μm filters. The Pall LG-6 ranked more efficient than the Medtronic 20 and Dideco 27-μm filters. The Cobe 43, Terumo 40, Medtronic 38, Terumo 37, and Gish 40-μm filters were less effective as a group compared with the other filters. For the 10 filters, blood flow resistance was not correlated to rated pore size. Generally, the smaller the pore rating, the higher the GME separation ability rank, except for the leuko-reduction filter, which performed more effectively than other large pore filters.

Air in the Left Brachiocephalic Vein Accompanied with Pulmonary Edema

A fifty-seven year old female patient visited the emergency department with tachypnea and a decreased mental status. The patient had been receiving fluid therapy at home and a bolus of air was injected into the fluid bottle in order to increase the infusion speed. Chest computed tomography revealed air in the left brachiocephalic vein that was accompanied with pulmonary edema the diagnosis of venous air embolism was made. Venous air embolism can result from various procedures that are performed in almost all clinical specialties and they can be fatal in cases of massive air embolism. Therefore, it is important for all clinicians to be aware of this problem. (Tuberc Respir Dis 2008;65:57-60)

Defective triggering of secondary peristalsis in patients with non‐erosive reflux disease

The pathophysiology of non-erosive reflux disease is poorly understood. Triggering of secondary peristalsis is impaired in patients with erosive esophagitis but data in patients with non-erosive reflux disease are lacking. The aim of this study was to evaluate the difference in esophageal motility between patients with non-erosive reflux disease and healthy subjects. Twenty patients with non-erosive reflux disease, with reflux symptoms occurring more than twice per week, and 20 healthy subjects of comparable age and sex underwent esophageal manometry. Primary peristalsis was tested with 10 swallows of a 5-mL water bolus. Secondary peristalsis was triggered by esophageal distention using a 20-mL air bolus, which was injected rapidly into the mid-esophagus. After 20 s, each stimulus was followed by a dry swallow to clear any residual air and then each stimulus was repeated five times. Basal lower esophageal sphincter pressure, pressure wave amplitude in the upper, middle and lower esophagus, wave velocity and the rates of successful primary peristalsis were similar in non-erosive reflux disease patients and controls. The rate of triggering of secondary peristalsis in patients with non-erosive reflux disease (median 20%, interquartile range 0-40%) was significantly lower (P < 0.0001) than that in healthy subjects (90%, 70-100%). When secondary peristalsis occurred in patients with non-erosive reflux disease, however, there were no differences in the amplitude and velocity of secondary peristalsis between the groups. Triggering of secondary peristalsis is defective in non-erosive reflux disease. This could lead to prolongation of the contact time between refluxed gastric acid and esophageal mucosa thereby leading to symptoms.

An investigation of central axis depth dose distribution perturbation due to an air gap between patient and bolus for electron beams

Electron beams can be used for the radiotherapy treatment of superficial cancers. In many cases of electron beam radiotherapy, tissue equivalent bolus material placed on the skin is to be used to enhance skin dose. An air gap might be present between the bolus and the skin due to variation in the patient contour. The impact of semi-infinite air gaps under bolus material on central axis depth dose distributions for electron beams was investigated in this study. Semi-infinite air gaps were introduced between bolus and the surface of a water phantom for air gap sizes up to 20.0 mm and for bolus thicknesses of 5, 10 and 15 mm. The electron beams studied had nominal energies of 6, 10 and 14 MeV and circular fields of 3, 5, 7 and 9 cm diameter. Depth dose measurements were carried out in the water phantom with a Scanditronix p-Si electron diode. It was found that the impact of an air gap is dependent on beam energy, field size, air gap size and bolus thickness used. The impact of the air gap on central axis depth dose distribution increased with decreasing field size, increasing air gap size, decreasing electron beam energy and increasing bolus thickness. For 15 mm bolus, 3 cm diameter circular field, 6 MeV beam and the 20 mm air gap, the maximum dose and the surface dose was reduced by approximately 60% and the depth of dose maximum shifted 3.5 mm. An air gap between bolus and a patient should be avoided to ensure that there is no impact on the treatment. The measured data in this study can be used to determine the likely degree of impact on the treatment, of unavoidable air gaps between bolus and the patient.

High-resolution gas volume change measurements bring new insights in pressure regulation of the middle ear

in this issue, the paper by Kania et al. ([7][1]) presents measurements and modeling results on the role of nitrogen in the gas exchange processes in the middle ear. The middle ear is a semirigid biological gas pocket that is closed most of the time. External influences, such as changing weather

LIFEBRIDGE: A Portable, Modular, Rapidly Available “Plug-and-Play” Mechanical Circulatory Support System

We describe the LIFEBRIDGE, a portable, modular, rapidly available "plug-and-play" mechanical circulatory support system, and report its experimental safety evaluation. The modular construction consists of a disposable patient module with cardiopulmonary bypass circuit, control module, and base module with power supply, embedded PC, and user interface. The system weighs about 20 kg, has a modular design, and has semi-automatic priming that allows action within 5 minutes, and a 7-step air elimination program that prevents air embolization. In eight pigs (85 +/- 10 kg) we investigated this system using central (right atrium and ascending aorta) cannulation (n = 4) or peripheral (iliac) cannulation (n = 4). Pump flows were 5.7 +/- 0.2 L/min with central and 4.1 +/- 0.2 L/min with peripheral cannulation, yielding sufficient animal perfusion and gas exchange. Using an intraaortic 8-MHz Doppler device, we demonstrated that venous air boluses of up to 100 mL were effectively removed, thus avoiding air embolization. Changing heights between animals and LIFEBRIDGE did not affect its proper action. This initial evaluation demonstrates that the LIFEBRIDGE is rapidly available, provides adequate perfusion and gas exchange, and operates safely even under simulated transport conditions.

Topical interleukin-8 antibody attracts leukocytes in a piglet lavage model

Acute respiratory distress syndrome (ARDS) in young infants is linked with a pulmonary inflammatory response part of which are increased interleukin-8 (IL-8) levels and migration of polymorphonuclear leukocytes (PMNL) into lung tissue. A topical application of an antibody against IL-8 might therefore decrease PMNL migration and improve lung function. Randomized, controlled, prospective animal study. Research laboratory of a university children's hospital. Anesthetized, mechanically ventilated newborn piglets (n=22) underwent repeated airway lavage to remove surfactant and to induce lung inflammation. Piglets then received either surfactant alone (S, n=8), or a topical antibody against IL-8 admixed to surfactant (S+IL-8, n=8), or an air bolus injection (control, n=6). After 6 h of mechanical ventilation following intervention, oxygenation [S 169+/-51 (SD) vs S+IL-8 139+/-61 mmHg] and lung function (compliance: S 1.3+/-0.4 vs S+IL-8 0.9+/-0.4 ml/cmH(2)O/kg; extra-vascular lung-water: S 27+/-9 vs S+IL-8 52+/-28 ml/kg) were worse in the S+IL-8 group because reactive IL-8 production [S 810 (median, range 447-2323] vs S+IL-8 3485 (628-16180) pg/ml; P<0.05) with facilitated migration of PMNL into lung tissue occurred. Moreover, antibody application caused augmented chemotactic potency of IL-8 [linear regression of migrated PMNL and IL-8 levels: S r(2)=0.30 (P=ns) vs S+IL-8 r(2)=0.89 (P=0.0002)]. Topical anti-IL-8 treatment after lung injury increases IL-8 production, PMNL migration, and worsens lung function in our piglet lavage model. This effect is in contrast to current literature using pre-lung injury treatment protocols. Our data do not support anti-IL-8 treatment in young infants with ARDS.

A Laboratory Evaluation of the Level 1 Rapid Infuser (H1025) and the Belmont Instrument Fluid Management System (FMS 2000) for Rapid Transfusion

In this investigation I compared the heating capabilities, infusion rates, and air management system of the new FMS 2000 and the Level 1 infusion systems. A rollerhead pump was placed at the position of the IV bag spikes on the Level 1 disposable set and used to match the flow of the rollerhead pump of the FMS 2000. Infusate temperature was measured at 250 and 500 mL/min by using packed red blood cells (PRBC) at the infusate supply and distal end of the disposable tubing. Tubing lengths were equal for both systems. Devices were set at maximum flow while temperatures were measured as described previously. Flow was measured with a graduated cylinder and stopwatch. Air management was evaluated with a 10-mL air bolus injected proximal to the heat exchanger at maximum flow. Air passing through the system was collected and measured. At 250 mL/min, both devices provided infusate at >or=37 degrees C. At 500 mL/min, only the FMS 2000 provided PRBC at >or=37 degrees C. PRBC infusate temperature decreased over time with the Level 1 device. The FMS 2000 delivered PRBC at its maximum flow rate of 500 mL/min. The Level 1 attained a maximum flow of 575 mL/min of PRBC with a temperature of 32 degrees C. Air (10 mL) was recovered from the distal tubing of the Level 1. No air was recovered from the tubing of the FMS 2000. In this laboratory investigation, the FMS 2000 performance was superior with respect to providing PRBC at physiologic temperatures (at 500 mL/min) and with respect to air detection and elimination compared with current widely used pressure-infuser technology. The FMS 2000 and Level 1 H1025 warming capabilities were similar at metered flows of 500 mL/min. At more rapid flow rates, which are achieved by the H1025, fluid warming decreases dramatically. The air-detection and -elimination system of the FMS 2000 is superior to that of the H1025.

Pulmonary oedema after venous air embolism during craniotomy

Pulmonary oedema after venous air embolism during craniotomy