Background Avoiding inadvertent hypothermia during surgery is important. Intravenous fluid warmer... more Background Avoiding inadvertent hypothermia during surgery is important. Intravenous fluid warmers used intraoperatively are critical for maintaining euthermia. We sought to prospectively evaluate the performance of the parylene-coated enFlow™ intravenous fluid warmer in patients undergoing surgery. Methods This was a prospective two-center observational clinical trial performed in inpatient surgical services of two large academic hospital systems. After informed consent, patients were enrolled in the study. All patients were adults scheduled for a surgery that was expected to last for at least 1 h with the administration of at least one liter of fluid warmed prior to infusion. Patient temperature was recorded in the preoperative unit, at the induction of anesthesia, and then every 15 or 30 minutes until the end of surgery. Temperature monitoring continued in the recovery unit. The parylene-coated enFlow™ intravenous fluid warmer was used in addition to the usual patient warming tec...
Objective: In the delivery of intravenous fluids, in-line warming devices frequently transfer hea... more Objective: In the delivery of intravenous fluids, in-line warming devices frequently transfer heat using a metal heating plate, which if uncoated can risk elution. This bench study examined extractable elements detected following long-term use of the parylene-coated enFlow® Disposable IV/Blood Warmer. Methods: We tested 16 clinically relevant challenge fluids typical of the surgical setting, including commercially available single donor blood and blood products as well as intravenous saline and electrolyte solutions. After 72 h of warming at 40°C (104°F) via the enFlow, analytical chemistry identified and quantified the most clinically significant extractable elements (arsenic, barium, cadmium, copper, and lead) to estimate chemical exposure. We also measured the extracted concentrations of these five elements following simulated use of the device with three solutions (Sterofundin ISO, Plasma-Lyte 148, and whole blood) that were pumped through the warmed device at two different flow...
Transpulmonary driving pressure (DPL) corresponds to the cyclical stress imposed on the lung pare... more Transpulmonary driving pressure (DPL) corresponds to the cyclical stress imposed on the lung parenchyma during tidal breathing and, therefore, can be used to assess the risk of ventilator-induced lung injury (VILI). Its measurement at the bedside requires the use of esophageal pressure (Peso), which is sometimes technically challenging. Recently, it has been demonstrated how in an animal model of ARDS, the transpulmonary pressure (PL) measured with Peso calculated with the absolute values method (PL = Paw—Peso) is equivalent to the transpulmonary pressure directly measured using pleural sensors in the central-dependent part of the lung. We hypothesized that, since the PL derived from Peso reflects the regional behavior of the lung, it could exist a relationship between regional parameters measured by electrical impedance tomography (EIT) and driving PL (DPL). Moreover, we explored if, by integrating airways pressure data and EIT data, it could be possible to estimate non-invasively ...
Objectives: Intravenous fluid warming devices with surface heating systems transfer heat using al... more Objectives: Intravenous fluid warming devices with surface heating systems transfer heat using aluminum blocks, which if uncoated elute toxic levels of aluminum into the infusate. This study examined extractable aluminum detected from prolonged use of the updated version of the enFlow® cartridge, which uses a parylene-coated aluminum heating block. Methods: In dynamic bench tests, we measured the concentration of aluminum that leached into three solutions (Sterofundin ISO, Plasma-Lyte 148, and whole blood) that were continuously pumped (0.2 and 5.5 mL min−1) and warmed to 40°C by the enFlow cartridge (parylene-coated) for 5 h. Prolonged quasi-static bench tests measured aluminum concentration in 16 solutions which were gently rocked within the enFlow cartridge (parylene-coated) for 72 h at 40°C. Aluminum concentrations were measured using inductively coupled mass spectroscopy and matrix blank corrected. Measured aluminum concentrations were compared to a Tolerable Exposure limit to ...
Supplemental material, sj-pdf-1-smo-10.1177_20503121211026849 for Fluid warming with parylene-coa... more Supplemental material, sj-pdf-1-smo-10.1177_20503121211026849 for Fluid warming with parylene-coated enFlow cartridge: Bench and pilot animal study of aluminum extraction due to prolonged use by Andreas D Waldmann, Edward A Rose and Michael J Pedro in SAGE Open Medicine
Figure S1. Ventrodorsal distribution of the regional difference between LIPr and UIPr. Regional d... more Figure S1. Ventrodorsal distribution of the regional difference between LIPr and UIPr. Regional differences between LIPr and UIPr in the different regions of interests (ROI); ROI1 = non-dependent; ROI1 + n = dependent lung. Values expressed as median [IQR]. (JPG 257 kb)
Regional inflection points from pressure-volume curves assessed by electrical impedance tomograph... more Regional inflection points from pressure-volume curves assessed by electrical impedance tomography as a guide to mechanical ventilation. Supplemental digital content. Additional results; Table S1. LIPg, UIPg, LIPrMAX, UIPrMIN, and Î PLIN at the 3 different levels of PEEP. (DOCX 16 kb)
Additional file 3: Video S3. Lung ultrasound images (LUS) of the isolated effect of 10 cmH2O of P... more Additional file 3: Video S3. Lung ultrasound images (LUS) of the isolated effect of 10 cmH2O of PEEP and postural recruitment maneuverâ case 3.
Additional file 1: Video S1. Lung ultrasound images (LUS) of the isolated effect of 10 cmH2O of P... more Additional file 1: Video S1. Lung ultrasound images (LUS) of the isolated effect of 10 cmH2O of PEEP and postural recruitment maneuverâ case 1.
SummaryBackgroundElectrical impedance tomography (EIT) is a method to measure regional impedance ... more SummaryBackgroundElectrical impedance tomography (EIT) is a method to measure regional impedance changes within the thorax. The total tidal impedance variation has been used to measure changes in tidal volumes in pigs, dogs and men.ObjectivesTo assess the ability of EIT to quantify changes in tidal volume in anaesthetised mechanically ventilated horses.Study designIn vivo experimental study.MethodsSix horses (mean ± s.d.: age 11.5 ± 7.5 years and body weight 491 ± 40 kg) were anaesthetised using isoflurane in oxygen. The lungs were mechanically ventilated using a volume‐controlled mode. With an end‐tidal carbon dioxide tension in the physiological range, and a set tidal volume (VTvent) of 11–16 mL/kg (baseline volume), EIT data and VT measured by conventional spirometry were collected over 1 min. Thereafter, VTvent was changed in 1 L steps until reaching 10 L. After, VTvent was reduced to 1 L below the baseline volume and then further reduced in 1 L steps until 4 L. On each VT step ...
OBJECTIVE Electrical impedance tomography (EIT) is a non-invasive and radiation-free bedside moni... more OBJECTIVE Electrical impedance tomography (EIT) is a non-invasive and radiation-free bedside monitoring technology, primarily used to monitor lung function. First experimental data shows that the descending aorta can be detected at different thoracic heights and might allow the assessment of central hemodynamics, i.e. stroke volume and pulse transit time. APPROACH First, the feasibility of localizing small non-conductive objects within a saline phantom model was evaluated. Second, this result was utilized for the detection of the aorta by EIT in ten anesthetized pigs with comparison to thoracic computer tomography (CT). Two EIT belts were placed at different thoracic positions and a bolus of hypertonic saline (10 ml, 20%) was administered into the ascending aorta while EIT data were recorded. EIT images were reconstructed using the GREIT model, based on the individual's thoracic contours. The resulting EIT images were analyzed pixel by pixel to identify the aortic pixel, in which the bolus caused the highest transient impedance peak in time. MAIN RESULTS In the phantom, small objects could be located at each position with a maximal deviation of 0.71 cm. In vivo, no significant differences between the aorta position measured by EIT and the anatomical aorta location were obtained for both measurement planes if the search was restricted to the dorsal thoracic region of interest (ROIs). SIGNIFICANCE It is possible to detect the descending aorta at different thoracic levels by EIT using an intra-aortic bolus of hypertonic saline. No significant differences in the position of the descending aorta on EIT images compared to CT images were obtained for both EIT belts.
DESCRIPTION Electrical Impedance Tomography EIT is used to analyse changes in lung properties dur... more DESCRIPTION Electrical Impedance Tomography EIT is used to analyse changes in lung properties during inhalation and exhalation. The methods to calculate indices of lung stretch and non-stretch are described.
Electrical impedance tomography (EIT) is a non-invasive real-time non-ionising imaging modality t... more Electrical impedance tomography (EIT) is a non-invasive real-time non-ionising imaging modality that has many applications. Since the first recorded use in 1978, the technology has become more widely used especially in human adult and neonatal critical care monitoring. Recently, there has been an increase in research on thoracic EIT in veterinary medicine. Real-time imaging of the thorax allows evaluation of ventilation distribution in anesthetised and conscious animals. As the technology becomes recognised in the veterinary community there is a need to standardize approaches to data collection, analysis, interpretation and nomenclature, ensuring comparison and repeatability between researchers and studies. A group of nineteen veterinarians and two biomedical engineers experienced in veterinary EIT were consulted and contributed to the preparation of this statement. The aim of this consensus is to provide an introduction to this imaging modality, to highlight clinical relevance and ...
Variation of poorly ventilated lung units (silent spaces) measured by electrical impedance tomogr... more Variation of poorly ventilated lung units (silent spaces) measured by electrical impedance tomography to dynamically assess recruitment. Additional information about the manuscript methods and additional data analysis are provided. Figure S1. Study protocol. Study protocol consisted of five consecutive phases. Figure S2. Hyperinflation (%) and nondependent lung compliance (ml/cmH2O) during the decremental step of the protocol. Hyperinflation (%) and nondependent lung compliance (ml/cmH2O) during the decremental step of the protocol. The hyperinflation value is expressed as a percentage of the total pixels and is relative to the last step of the PEEP titration trial (in this case, PEEPâ =â 5 cmH2O). (ZIP 178 kb)
Background:Alarm fatigue is a significant problem in healthcare, particularly in high acuity sett... more Background:Alarm fatigue is a significant problem in healthcare, particularly in high acuity settings such as intensive care, surgery, and emergency departments. Alarms are triggered by various devices such as anesthesia machines, ventilators, patient monitors or humidifiers. Heated humidifiers (HH) used with mechanical ventilators, while necessary to prevent other complications associated with mechanical ventilator, may cause condensation in the ventilator circuit, prompting occlusion alarms indicating a risk for the patient. Technological advances in heated humidifier (HH) circuits may reduce rainout and therefore occlusion alarms. Methods:Bench experiments measured alarms and rainout of two commercially available humidifiers (AirLife DuoTherm™ and Fisher & Paykel MR850) and four different pediatric and adult patient’s breathing. The tests examined condensation accumulation after 24 hours of low-, nominal-, or high-flow rates of gas at low-, nominal-, and high-ambient temperature ...
Background Avoiding inadvertent hypothermia during surgery is important. Intravenous fluid warmer... more Background Avoiding inadvertent hypothermia during surgery is important. Intravenous fluid warmers used intraoperatively are critical for maintaining euthermia. We sought to prospectively evaluate the performance of the parylene-coated enFlow™ intravenous fluid warmer in patients undergoing surgery. Methods This was a prospective two-center observational clinical trial performed in inpatient surgical services of two large academic hospital systems. After informed consent, patients were enrolled in the study. All patients were adults scheduled for a surgery that was expected to last for at least 1 h with the administration of at least one liter of fluid warmed prior to infusion. Patient temperature was recorded in the preoperative unit, at the induction of anesthesia, and then every 15 or 30 minutes until the end of surgery. Temperature monitoring continued in the recovery unit. The parylene-coated enFlow™ intravenous fluid warmer was used in addition to the usual patient warming tec...
Objective: In the delivery of intravenous fluids, in-line warming devices frequently transfer hea... more Objective: In the delivery of intravenous fluids, in-line warming devices frequently transfer heat using a metal heating plate, which if uncoated can risk elution. This bench study examined extractable elements detected following long-term use of the parylene-coated enFlow® Disposable IV/Blood Warmer. Methods: We tested 16 clinically relevant challenge fluids typical of the surgical setting, including commercially available single donor blood and blood products as well as intravenous saline and electrolyte solutions. After 72 h of warming at 40°C (104°F) via the enFlow, analytical chemistry identified and quantified the most clinically significant extractable elements (arsenic, barium, cadmium, copper, and lead) to estimate chemical exposure. We also measured the extracted concentrations of these five elements following simulated use of the device with three solutions (Sterofundin ISO, Plasma-Lyte 148, and whole blood) that were pumped through the warmed device at two different flow...
Transpulmonary driving pressure (DPL) corresponds to the cyclical stress imposed on the lung pare... more Transpulmonary driving pressure (DPL) corresponds to the cyclical stress imposed on the lung parenchyma during tidal breathing and, therefore, can be used to assess the risk of ventilator-induced lung injury (VILI). Its measurement at the bedside requires the use of esophageal pressure (Peso), which is sometimes technically challenging. Recently, it has been demonstrated how in an animal model of ARDS, the transpulmonary pressure (PL) measured with Peso calculated with the absolute values method (PL = Paw—Peso) is equivalent to the transpulmonary pressure directly measured using pleural sensors in the central-dependent part of the lung. We hypothesized that, since the PL derived from Peso reflects the regional behavior of the lung, it could exist a relationship between regional parameters measured by electrical impedance tomography (EIT) and driving PL (DPL). Moreover, we explored if, by integrating airways pressure data and EIT data, it could be possible to estimate non-invasively ...
Objectives: Intravenous fluid warming devices with surface heating systems transfer heat using al... more Objectives: Intravenous fluid warming devices with surface heating systems transfer heat using aluminum blocks, which if uncoated elute toxic levels of aluminum into the infusate. This study examined extractable aluminum detected from prolonged use of the updated version of the enFlow® cartridge, which uses a parylene-coated aluminum heating block. Methods: In dynamic bench tests, we measured the concentration of aluminum that leached into three solutions (Sterofundin ISO, Plasma-Lyte 148, and whole blood) that were continuously pumped (0.2 and 5.5 mL min−1) and warmed to 40°C by the enFlow cartridge (parylene-coated) for 5 h. Prolonged quasi-static bench tests measured aluminum concentration in 16 solutions which were gently rocked within the enFlow cartridge (parylene-coated) for 72 h at 40°C. Aluminum concentrations were measured using inductively coupled mass spectroscopy and matrix blank corrected. Measured aluminum concentrations were compared to a Tolerable Exposure limit to ...
Supplemental material, sj-pdf-1-smo-10.1177_20503121211026849 for Fluid warming with parylene-coa... more Supplemental material, sj-pdf-1-smo-10.1177_20503121211026849 for Fluid warming with parylene-coated enFlow cartridge: Bench and pilot animal study of aluminum extraction due to prolonged use by Andreas D Waldmann, Edward A Rose and Michael J Pedro in SAGE Open Medicine
Figure S1. Ventrodorsal distribution of the regional difference between LIPr and UIPr. Regional d... more Figure S1. Ventrodorsal distribution of the regional difference between LIPr and UIPr. Regional differences between LIPr and UIPr in the different regions of interests (ROI); ROI1 = non-dependent; ROI1 + n = dependent lung. Values expressed as median [IQR]. (JPG 257 kb)
Regional inflection points from pressure-volume curves assessed by electrical impedance tomograph... more Regional inflection points from pressure-volume curves assessed by electrical impedance tomography as a guide to mechanical ventilation. Supplemental digital content. Additional results; Table S1. LIPg, UIPg, LIPrMAX, UIPrMIN, and Î PLIN at the 3 different levels of PEEP. (DOCX 16 kb)
Additional file 3: Video S3. Lung ultrasound images (LUS) of the isolated effect of 10 cmH2O of P... more Additional file 3: Video S3. Lung ultrasound images (LUS) of the isolated effect of 10 cmH2O of PEEP and postural recruitment maneuverâ case 3.
Additional file 1: Video S1. Lung ultrasound images (LUS) of the isolated effect of 10 cmH2O of P... more Additional file 1: Video S1. Lung ultrasound images (LUS) of the isolated effect of 10 cmH2O of PEEP and postural recruitment maneuverâ case 1.
SummaryBackgroundElectrical impedance tomography (EIT) is a method to measure regional impedance ... more SummaryBackgroundElectrical impedance tomography (EIT) is a method to measure regional impedance changes within the thorax. The total tidal impedance variation has been used to measure changes in tidal volumes in pigs, dogs and men.ObjectivesTo assess the ability of EIT to quantify changes in tidal volume in anaesthetised mechanically ventilated horses.Study designIn vivo experimental study.MethodsSix horses (mean ± s.d.: age 11.5 ± 7.5 years and body weight 491 ± 40 kg) were anaesthetised using isoflurane in oxygen. The lungs were mechanically ventilated using a volume‐controlled mode. With an end‐tidal carbon dioxide tension in the physiological range, and a set tidal volume (VTvent) of 11–16 mL/kg (baseline volume), EIT data and VT measured by conventional spirometry were collected over 1 min. Thereafter, VTvent was changed in 1 L steps until reaching 10 L. After, VTvent was reduced to 1 L below the baseline volume and then further reduced in 1 L steps until 4 L. On each VT step ...
OBJECTIVE Electrical impedance tomography (EIT) is a non-invasive and radiation-free bedside moni... more OBJECTIVE Electrical impedance tomography (EIT) is a non-invasive and radiation-free bedside monitoring technology, primarily used to monitor lung function. First experimental data shows that the descending aorta can be detected at different thoracic heights and might allow the assessment of central hemodynamics, i.e. stroke volume and pulse transit time. APPROACH First, the feasibility of localizing small non-conductive objects within a saline phantom model was evaluated. Second, this result was utilized for the detection of the aorta by EIT in ten anesthetized pigs with comparison to thoracic computer tomography (CT). Two EIT belts were placed at different thoracic positions and a bolus of hypertonic saline (10 ml, 20%) was administered into the ascending aorta while EIT data were recorded. EIT images were reconstructed using the GREIT model, based on the individual's thoracic contours. The resulting EIT images were analyzed pixel by pixel to identify the aortic pixel, in which the bolus caused the highest transient impedance peak in time. MAIN RESULTS In the phantom, small objects could be located at each position with a maximal deviation of 0.71 cm. In vivo, no significant differences between the aorta position measured by EIT and the anatomical aorta location were obtained for both measurement planes if the search was restricted to the dorsal thoracic region of interest (ROIs). SIGNIFICANCE It is possible to detect the descending aorta at different thoracic levels by EIT using an intra-aortic bolus of hypertonic saline. No significant differences in the position of the descending aorta on EIT images compared to CT images were obtained for both EIT belts.
DESCRIPTION Electrical Impedance Tomography EIT is used to analyse changes in lung properties dur... more DESCRIPTION Electrical Impedance Tomography EIT is used to analyse changes in lung properties during inhalation and exhalation. The methods to calculate indices of lung stretch and non-stretch are described.
Electrical impedance tomography (EIT) is a non-invasive real-time non-ionising imaging modality t... more Electrical impedance tomography (EIT) is a non-invasive real-time non-ionising imaging modality that has many applications. Since the first recorded use in 1978, the technology has become more widely used especially in human adult and neonatal critical care monitoring. Recently, there has been an increase in research on thoracic EIT in veterinary medicine. Real-time imaging of the thorax allows evaluation of ventilation distribution in anesthetised and conscious animals. As the technology becomes recognised in the veterinary community there is a need to standardize approaches to data collection, analysis, interpretation and nomenclature, ensuring comparison and repeatability between researchers and studies. A group of nineteen veterinarians and two biomedical engineers experienced in veterinary EIT were consulted and contributed to the preparation of this statement. The aim of this consensus is to provide an introduction to this imaging modality, to highlight clinical relevance and ...
Variation of poorly ventilated lung units (silent spaces) measured by electrical impedance tomogr... more Variation of poorly ventilated lung units (silent spaces) measured by electrical impedance tomography to dynamically assess recruitment. Additional information about the manuscript methods and additional data analysis are provided. Figure S1. Study protocol. Study protocol consisted of five consecutive phases. Figure S2. Hyperinflation (%) and nondependent lung compliance (ml/cmH2O) during the decremental step of the protocol. Hyperinflation (%) and nondependent lung compliance (ml/cmH2O) during the decremental step of the protocol. The hyperinflation value is expressed as a percentage of the total pixels and is relative to the last step of the PEEP titration trial (in this case, PEEPâ =â 5 cmH2O). (ZIP 178 kb)
Background:Alarm fatigue is a significant problem in healthcare, particularly in high acuity sett... more Background:Alarm fatigue is a significant problem in healthcare, particularly in high acuity settings such as intensive care, surgery, and emergency departments. Alarms are triggered by various devices such as anesthesia machines, ventilators, patient monitors or humidifiers. Heated humidifiers (HH) used with mechanical ventilators, while necessary to prevent other complications associated with mechanical ventilator, may cause condensation in the ventilator circuit, prompting occlusion alarms indicating a risk for the patient. Technological advances in heated humidifier (HH) circuits may reduce rainout and therefore occlusion alarms. Methods:Bench experiments measured alarms and rainout of two commercially available humidifiers (AirLife DuoTherm™ and Fisher & Paykel MR850) and four different pediatric and adult patient’s breathing. The tests examined condensation accumulation after 24 hours of low-, nominal-, or high-flow rates of gas at low-, nominal-, and high-ambient temperature ...
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