Air-filled Catheters Research Articles

Evaluation of the TraumaGuard Balloon-in-Balloon Catheter Design for Intra-Abdominal Pressure Monitoring: Insights from Pig and Human Cadaver Studies.

Introduction: Intra-abdominal pressure (IAP) monitoring is crucial for the detection and prevention of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). In the 1970s, air-filled catheters (AFCs) for urodynamic studies were introduced as a solution to overcome the limitations of water-perfused catheters. Recent studies have shown that for correct IAP measurement with traditional AFC, the bladder needs to be primed with 25 mL of saline solution to allow pressure wave transmission to the transducer outside of the body, which limits continuous IAP monitoring. Methods: In this study, a novel triple balloon, air-filled TraumaGuard (TG) catheter system from Sentinel Medical Technologies (Jacksonville, FL, USA) with a unique balloon-in-balloon design was evaluated in a porcine and cadaver model of IAH via laparoscopy (IAPgold). Results: In total, 27 and 86 paired IAP measurements were performed in two pigs and one human cadaver, respectively. The mean IAPTG was 20.7 ± 10.7 mmHg compared to IAPgold of 20.3 ± 10.3 mmHg in the porcine study. In the cadaver investigation, the mean IAPTG was 15.6 ± 10.8 mmHg compared to IAPgold of 14.4 ± 10.4 mmHg. The correlation, concordance, bias, precision, limits of agreement, and percentage error were all in accordance with the WSACS (Abdominal Compartment Society) recommendations and guidelines for research. Conclusions: These findings support the use of the TG catheter for continuous IAP monitoring, providing early detection of elevated IAP, thus enabling the potential for prevention of IAH and ACS. Confirmation studies with the TraumaGuard system in critically ill patients are warranted to further validate these findings.

Correlation between obesity-related measurements and initial and initial resting intravesical and abdominal pressures in urodynamic study using air-filled catheter system.

To establish the initial (before pressure equilibrium) and initial resting intravesical and abdominal pressure in the sitting position using air-filled catheters, to assess the correlation between these pressures and obesity-related measurements, and to estimate if obesity-related measurements can be a guide to interpret initial and initial resting pressures in urodynamic testing. Patients with non-neurogenic lower urinary tract symptoms referred for urodynamic testing in our center were consecutively enrolled in a prospective study from August 2022 to October 2022. The correlation between the initial and initial resting pressures (before and after pressure equilibrium) and obesity-related measurements were analyzed using Pearson's correlation coefficient and multiple linear regression analysis. Ninety-eight patients aged 56 ± 16 were studied. The 95% range of the initial intravesical and abdominal pressure were 18-42 cmH2 O and 21-60 cmH2 O, respectively. The initial resting intravesical, abdominal, and detrusor pressure in the 95% range were 17-41, 16-42, and -5 to 4 cmH2 O, respectively. Over the multiple analysis, abdominal fat thickness, and body mass index (BMI) correlated independently with initial intravesical pressure, and only visceral fat grade correlated with initial abdominal pressure. BMI correlated independently with initial resting intravesical pressure. Our results determined the ranges of values of both initial and initial resting pressures in the air-charged system. Meanwhile, the present study indicated the obesity-related measurements may be used as a guide to interpret the initial and initial resting pressures in urodynamic testing, and may provide a reference for the quality control of these pressures.

Chest compressions during ventilation in out-of-hospital cardiac arrest cause reversed airflow

AimDuring cardiopulmonary resuscitation, once the patient is intubated, compressions and ventilations are performed simultaneously. Chest compressions during the inspiratory phase of ventilation may force air out of the lungs, causing so-called “reversed airflow”, which may lead to ineffective ventilation. The purpose of this study is to determine the occurrence of this phenomenon and to quantify the volume of reversed airflow. MethodsObservational study. During manual ventilation of intubated patients receiving chest compressions, the pressure gradient over the endotracheal tube was measured using two air-filled catheters connected to a custom-made portable device. Chest compression data were measured using an accelerometer on a Zoll E- series defibrillator. All data are reported as mean (standard deviation; range). ResultsTwenty-five patients and a total of 368 ventilations were studied, on average 15 (6; 10–30) per patient. The mean tidal volume, minute volume and ventilation rate were respectively 690 ml (160; 240–1260), 10.5 l/min (4.8; 4.4–22.1) and 18/min (6; 6–35). Reversed airflow was observed in 21/25 patients (84%) and in 65% of all ventilations, with on average two episodes per ventilation. Fifty-five percent of the chest compressions during the inspiratory phase of the ventilation generated reversed airflow. The mean volume of the reversed airflow was 96 ml per episode (52; 12–364). ConclusionChest compressions during ventilation in intubated patients generated reversed airflow in most patients. There was wide variation in the number of episodes and volume of the reversed airflow between patients. The effect of this phenomenon on the efficacy of ventilation during resuscitation and on outcome needs further investigation.

Video Urodynamic Study in Female Adults With Air-filled Catheters: A Health-care Training Video

To take the first step toward standardization of UDS with air-filled catheters, we present a video documenting a procedure for performing video UDS with air-filled catheters in female adults. According to The International Consultation on Incontinence (ICS), the aim of urodynamic studies (UDS) in clinical practice is to evaluate a patient's lower urinary tract function with at least 1 complete and representative filling-voiding-post-voiding cycle by testing with relevant pressures and flowmetry.1 International guidelines state that UDS is preferably performed with fluid-filled catheters.2,3 However, although air-filled catheters are widely used, further research is needed before these catheters can be recommended for routine clinical use.4 To our knowledge, no guide on how to perform UDS with air-filled catheters has been published. The UDS was conducted according to local protocol. The ICS recommendations mentioned above were used as a template for this protocol. Intravesical, intraurethral, and abdominal pressure were measured. The cysto-urethrometry filling cycle and pressure-flow study were performed in sitting position. Fluoroscopy was performed during filling and voiding phase at fixed points. Before starting the filling cycle, the patient was verbally instructed with visual aids (Fig.1) to report bladder sensation. Filling rate was 10% of the largest voiding flow rate reported on the frequency volume chart. Initial baseline pressure was measured, and a cough pressure response test was performed. Our procedure for video UDS with air-filled catheters in a female adult was demonstrated in an instruction video. An instruction video on a standardized UDS with air-filled catheters in female adults is presented to take the first step toward standardization and for the benefit of health-care workers performing such tests.

Air filled, including "air-charged," catheters in urodynamic studies: does the evidence justify their use?

Air filled catheters (AFCs) have been actively marketed for the past few years and in some geographic areas are widely used. However, as the scientific basis for introduction of this technology for pressure measurement in urodynamics was not clear, a study group examined the evidence. A search of the peer reviewed literature was carried out. Four papers were identified, of which two were laboratory experiments and two were clinical papers, in female patients, that compared the pressures recorded by AFCs and those recorded using the traditional water filled catheters (WFCs). These data show that there are differences between the pressures measured by the two types of catheters. As yet, the reasons for these differences are not clear. There should be further systematic laboratory and clinical research before AFCs can be recommended for routine clinical use. We would recommend that a professional worldwide multidisciplinary scientific society, such as the International Continence Society, should work with manufacturers and regulatory bodies to ensure that this urodynamic method is properly scientifically evaluated, in the wider interests of patient safety.

Liquid- and Air-Filled Catheters without Balloon as an Alternative to the Air-Filled Balloon Catheter for Measurement of Esophageal Pressure

BackgroundMeasuring esophageal pressure (Pes) using an air-filled balloon catheter (BC) is the common approach to estimate pleural pressure and related parameters. However, Pes is not routinely measured in mechanically ventilated patients, partly due to technical and practical limitations and difficulties. This study aimed at comparing the conventional BC with two alternative methods for Pes measurement, liquid-filled and air-filled catheters without balloon (LFC and AFC), during mechanical ventilation with and without spontaneous breathing activity. Seven female juvenile pigs (32–42 kg) were anesthetized, orotracheally intubated, and a bundle of an AFC, LFC, and BC was inserted in the esophagus. Controlled and assisted mechanical ventilation were applied with positive end-expiratory pressures of 5 and 15 cmH2O, and driving pressures of 10 and 20 cmH2O, in supine and lateral decubitus.Main ResultsCardiogenic noise in BC tracings was much larger (up to 25% of total power of Pes signal) than in AFC and LFC (<3%). Lung and chest wall elastance, pressure-time product, inspiratory work of breathing, inspiratory change and end-expiratory value of transpulmonary pressure were estimated. The three catheters allowed detecting similar changes in these parameters between different ventilation settings. However, a non-negligible and significant bias between estimates from BC and those from AFC and LFC was observed in several instances.ConclusionsIn anesthetized and mechanically ventilated pigs, the three catheters are equivalent when the aim is to detect changes in Pes and related parameters between different conditions, but possibly not when the absolute value of the estimated parameters is of paramount importance. Due to a better signal-to-noise ratio, and considering its practical advantages in terms of easier calibration and simpler acquisition setup, LFC may prove interesting for clinical use.

Comparison of Air-Coupled Balloon Esophageal and Anorectal Manometry Catheters with Solid-State Esophageal Manometry and Water-Perfused Anorectal Manometry Catheters

Clinical gastrointestinal manometry studies are currently performed with multilumen water-perfused polyvinyl or strain gauge sensor solid-state catheters. A disposable catheter incorporating air-filled balloons has been developed with performance characteristics suitable for esophageal and anorectal manometry studies. Our aim was to compare esophageal and anorectal pressure measurements using this newly developed catheter with measurements obtained using standard solid-state or water-perfused catheters. Measurements of resting LES pressure, esophageal contraction amplitudes, and anorectal rest and squeeze pressures were obtained in 10 healthy volunteers using a solid-state esophageal catheter, a water-perfused anorectal catheter, and air-filled balloon esophageal and anorectal catheters. Correlation coefficient analysis demonstrated that LES pressures, esophageal contraction amplitudes, and anorectal resting and squeeze pressures were not significantly among between the different catheters. We conclude that recently developed air-filled balloon esophageal and anorectal manometry catheters provide very similar measurements of LES, esophageal body, and anorectal sphincter pressures compared to presently used manometry catheters.

A technique for measuring frequency response of pressure, volume, and flow transducers.

A device and methodology is presented for testing the frequency response of pressure, volume, or flow transducers. Also reported are responses of selected transducers of all three types over the range of 2--120 Hz. Several pressure transducers tested had good frequency response when connected to the test system with a minimum of interconnecting fittings; others did not. Use of additional connectors degraded the response as did the addition of air-filled catheters. The frequency response of the pneumotachometers tested were influenced largely by the response characteristics of the associated pressure transducer and interconnecting fittings. These results emphasize the need to test the response characteristics of any transducer with specific connectors and fittings that are to be used to make the actual measurements of pressure, volume, or flow.

1170 PHARYNGEAL PRESSURE DURING NASAL CPAP

The pressure in an infant's airway when CPAP is delivered by nasal prongs has not been previously reported. Using air-filled catheters and differential pressure transducers we have measured simultaneous pressures in nasal prongs (Ppr) and pharynx(Ppx) in 18 newborns. After a steady state was achieved, end expiratory pressure in five consecutive breaths was measured: these were usually identical but otherwise were averaged. The pressure difference (Ppr-Ppx=ΔP) was low in infants with visual evidence of tight palato-glossal apposition. Though there was much variation, babies whose mouths were a) spontaneously open without tongue/palate seal had a %ΔP=48% ± 4% (weighted average ± SEM), b) spontaneously closed or who had a demonstrable seal had a %ΔP=8% ± 3%; these are significantly different means (p=<.001). In the latter group there was a close correlation between Ppr and Ppx (r = 0.965). The ability to maintain a good seal was not related to gestational age, post natal age, severity or type of disease. However, babies who maintained a good seal frequently had an active gag reflex (Fishers exact test p=.04). Spontaneous closure of the mouth usually indicated a good seal but forcible closure did not consistently decrease the pressure drop.