scholarly journals Large variations of oxygen delivery in self-inflating resuscitation bags used for preoxygenation - a mechanical simulation

2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Sven Grauman ◽  
Joakim Johansson ◽  
Thomas Drevhammar
Keyword(s):  
Airway Management ◽  
Oxygen Delivery ◽  
Spontaneous Breathing ◽  
Gas Flow ◽  
Minute Volume ◽  
Minute Period ◽  
Common Notion ◽  
High Fraction ◽  
Emergency Anaesthesia

Abstract Background Self-Inflating Resuscitation Bags (SIRB) are common and essential tools in airway management and ventilation. They are often used in resuscitation and emergency anaesthesia outside the operating theatre. There is a common notion that all SIRBs applied with a tight sealed mask will deliver close to 100 % oxygen during spontaneous breathing. The aim of the study was to measure the oxygen delivery of six commonly used SIRBs in a mechanical spontaneous breathing adult in vitro model. Methods Three SIRBs of each of the six models were evaluated for oxygen delivery during simulated breathing with an adult mechanical lung. The test was repeated three times per device (54 tests in total). The breathing profile was fixed to a minute volume of 10 L/min, a tidal volume of 500 mL and the SIRBs supplied with an oxygen fresh gas flow of 15 L/min. The fraction of delivered oxygen (FDO2) was measured over a three-minute period. Average FDO2 was calculated and compared at 30, 60 and 90 s. Results At 90 s all models had reached a stable FDO2. Average FDO2 at 90 s; Ambu Oval Plus 99,5 %; Ambu Spur II 99,8 %; Intersurgical BVM Resuscitator 76,7 %; Laerdal Silicone 97,3 %; Laerdal The Bag II 94,5 % and the O-Two Smart Bag 39,0 %. All differences in FDO2 were significant apart from the two Ambu models. Conclusions In simulated spontaneous breathing, four out of six (by Ambu and Laerdal) Self-Inflating Resuscitation Bags delivered a high fraction of oxygen while two (Intersurgical and O-two) underperformed in oxygen delivery. These large variations confirm results reported in other studies. It is our opinion that underperforming Self-Inflating Resuscitation Bags might pose a serious threat to patients’ health if used in resuscitation and anaesthesia. Manufacturers of Self-Inflating Resuscitation Bags rarely provide information on performance for spontaneous breathing. This poses a challenge to all organizations that need their devices to deliver adequate oxygen during spontaneous breathing.

scholarly journals The Effect of Positive End Expiratory Pressure on Rebreathing and Gas Dilution in the Ayre's T-Piece System—A Laboratory Study

1978 ◽  
Vol 6 (1) ◽  
pp. 19-25 ◽  
Author(s):  
T. L. Dobbinson ◽  
E. R. Fawcett ◽  
D. P. G. Bolton
Keyword(s):  
Spontaneous Breathing ◽  
Gas Flow ◽  
Minute Volume ◽  
Lung Model ◽  
Positive End Expiratory Pressure ◽  
System A ◽  
Test Conditions ◽  
Controlled Breathing ◽  
Gas Dilution ◽  
End Tidal

The effect of positive end expiratory pressure on the function of the Ayre's T-Piece System was studied using a simple lung model. Positive end expiratory pressure did not affect end tidal CO 2 during “controlled breathing” but caused an increase during “spontaneous breathing” when fresh gas flow was less than 3 times the minute volume. Gas dilution did not occur under any of the test conditions.

Reduced high-energy phosphate levels in rat hearts. I. Effects of alloxan diabetes

1976 ◽  
Vol 230 (6) ◽  
pp. 1744-1750 ◽  
Author(s):  
TB Allison ◽  
SP Bruttig ◽  
Crass MF ◽  
RS Eliot ◽  
JC Shipp
Keyword(s):  
Oxidative Metabolism ◽  
Oxygen Delivery ◽  
Rat Heart ◽  
High Energy ◽  
Diabetic Rat ◽  
High Energy Phosphate ◽  
Atp Production ◽  
Rat Hearts

Significant alterations in heart carbohydrate and lipid metabolism are present 48 h after intravenous injection of alloxan (60 mg/kg) in rats. It has been suggested that uncoupling of oxidative phosphorylation occurs in the alloxanized rat heart in vivo, whereas normal oxidative metabolism has been demonstrated in alloxan-diabetic rat hearts perfused in vitro under conditions of adequate oxygen delivery. We examined the hypothesis that high-energy phosphate metabolism might be adversely affected in the alloxan-diabetic rat heart in vivo. Phosphocreatine and ATP were reduced by 58 and 45%, respectively (P is less than 0.001). Also, oxygen-dissociation curves were shifted to the left by 4 mmHg, and the rate of oxygen release from blood was reduced by 21% (P is less than 0.01). Insulin administration normalized heart high-energy phosphate compounds. ATP production was accelerated in diabetic hearts perfused in vitro with a well-oxygenated buffer. These studies support the hypothesis that oxidative ATP production in the alloxan-diabetic rat heart is reduced and suggest that decreased oxygen delivery may have a regulatory role in the oxidative metabolism of the diabetic rat heart.

Dimensional variations of left-sided double-lumen endobronchial tubes: an observational study

2019 ◽  
Author(s):  
Niels Hegland ◽  
Sebastian Schnitzler ◽  
Jan Ellensohn ◽  
Marc P Steurer ◽  
Markus Weiss ◽  
...  
Keyword(s):  
Observational Study ◽  
Airway Management ◽  
Double Lumen ◽  
Tube Size ◽  
Size Selection ◽  
Dimensional Parameters

Abstract Background: Tube size selection is critical in ventilating patient`s lungs using double-lumen endobronchial tubes. Little information about relevant parameters is readily available from manufacturers. Methods: In this observational study in a benchmark in-vitro setup, several dimensional parameters of four sizes of left-sided double-lumen endobronchial tubes from six different manufacturers were assessed, such as distances and diameters of tube shaft, cuff lengths and diameters as well the angle at the tip. Results: Endobronchial tubes of ostensibly the same size revealed wide variation in measured parameters between brands from different manufacturers. In some parameters, there was an overlap between different sizes from the same manufacturer, i.e. diameters and distances did not increase with increasing nominal endobronchial tube size. The information about dimensions of endobronchial tubes provided by manufacturers’ leaflets is insufficient. Conclusions: Endobronchial tube size selection is complicated because clinically relevant parameters are unknown and vary considerably between different manufacturers. Keywords: Airway management, double-lumen endobronchial tubes

In vitro evaluation of delays in the adjustment of the fraction of inspired oxygen during CPAP: effect of flow and volume

2020 ◽  
pp. fetalneonatal-2020-319058
Author(s):  
Christoph E. Schwarz ◽  
Gordon Lightbody ◽  
Ingo Müller-Hansen ◽  
Jörg Arand ◽  
Christian F. Poets ◽  
...  
Keyword(s):  
Gas Flow ◽  
Closed Loop ◽  
Volume Flow ◽  
Target Range ◽  
Equilibration Time ◽  
Ventilator Circuit ◽  
Fraction Of Inspired Oxygen ◽  
Inspired Oxygen

BackgroundAdjusting the fraction of inspired oxygen (FiO2) delivered to preterm infants to keep their oxygen saturation within target range remains challenging. Closed-loop automated FiO2 control increases the time infants spend within the assigned target range. The delay with which FiO2 adjustments at the ventilator result in a change in the inspired gas limits the performance of both manual and automated controls.ObjectiveTo evaluate the equilibration time (Teq) between FiO2 adjustments and changes in FiO2 reaching the patient.MethodsIn vitro determination of the delay in FiO2 adjustments at the ventilator at 5 and 8 L/min of gas flow and two different humidifier/ventilator circuit volumes (840 and 432 mL).ResultsTeq values were 31, 23, 20 and 17 s for the volume–flow combinations 840 mL+5 L/min, 840 mL+8 L/min, 432 mL+5 L/min and 432 mL+8 L/min, respectively.ConclusionThe identified delay seems clinically relevant and should be taken into account during manual and automatic control of FiO2.

Effects of local cooling or heating in deeply hypothermic rats

1960 ◽  
Vol 15 (3) ◽  
pp. 435-439 ◽  
Author(s):  
D. P. Orchard ◽  
E. F. Adolph
Keyword(s):  
Blood Flow ◽  
Core Temperature ◽  
Oxygen Delivery ◽  
Spontaneous Breathing ◽  
Artificial Ventilation ◽  
Vena Cava ◽  
Local Cooling ◽  
The Mean ◽  
Ventilation Of The Lungs ◽  
The Brain

Rats were cooled to 17°C core temperature, and then either the head or the chest was further cooled by 5° – 10°. Thermocouples in the hypothalamus and in the vena cava recorded the differences of temperature; electrocardiograms and breathing were observed. Breathing could cease reversibly when the head was cooled and also after a period of gasping whenever the heart was much cooler than the head. Artificial ventilation of the lungs with air did not modify the result of restricted blood flow. Whenever the brain was cooler than the heart, however, artificial ventilation with air could replace spontaneous breathing; the blood flow was then usually adequate. Artificial ventilation with nitrogen reduced the time within which recovery was possible. In general the warmest tissue (head or chest) determined the time of endurance without adequate delivery of oxygen from lungs and blood. Any local cooling failed to increase the rat's endurance of oxygen lack. The results are interpreted to mean that failures to survive below 14°C for 1 hour are due to inadequate oxygen delivery. However, even oxygen delivery believed to be adequate did not allow indefinite survival; 2 hours remained the mean tolerance time below 14°C. Submitted on November 23, 1959

Micrometer-scale oxygen delivery rearranges cells and prevents necrosis in tumor tissue in vitro

2012 ◽  
Vol 28 (2) ◽  
pp. 515-525 ◽  
Author(s):  
Bhushan J. Toley ◽  
Jaehyun Park ◽  
Byoung-Jin Kim ◽  
Raja Venkatasubramanian ◽  
Michel M. Maharbiz ◽  
...  
Keyword(s):  
Oxygen Delivery ◽  
Tumor Tissue ◽  
Micrometer Scale

scholarly journals A neuroglobin-based high-affinity ligand trap reverses carbon monoxide–induced mitochondrial poisoning

2020 ◽  
Vol 295 (19) ◽  
pp. 6357-6371 ◽  
Author(s):  
Jason J. Rose ◽  
Kaitlin A. Bocian ◽  
Qinzi Xu ◽  
Ling Wang ◽  
Anthony W. DeMartino ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Mitochondrial Respiration ◽  
Oxygen Delivery ◽  
Oxygen Electrode ◽  
Heart Tissue ◽  
Tissue Respiration ◽  
Co Poisoning ◽  
Affinity Ligand

Carbon monoxide (CO) remains the most common cause of human poisoning. The consequences of CO poisoning include cardiac dysfunction, brain injury, and death. CO causes toxicity by binding to hemoglobin and by inhibiting mitochondrial cytochrome c oxidase (CcO), thereby decreasing oxygen delivery and inhibiting oxidative phosphorylation. We have recently developed a CO antidote based on human neuroglobin (Ngb-H64Q-CCC). This molecule enhances clearance of CO from red blood cells in vitro and in vivo. Herein, we tested whether Ngb-H64Q-CCC can also scavenge CO from CcO and attenuate CO-induced inhibition of mitochondrial respiration. Heart tissue from mice exposed to 3% CO exhibited a 42 ± 19% reduction in tissue respiration rate and a 33 ± 38% reduction in CcO activity compared with unexposed mice. Intravenous infusion of Ngb-H64Q-CCC restored respiration rates to that of control mice correlating with higher electron transport chain CcO activity in Ngb-H64Q-CCC–treated compared with PBS-treated, CO-poisoned mice. Further, using a Clark-type oxygen electrode, we measured isolated rat liver mitochondrial respiration in the presence and absence of saturating solutions of CO (160 μm) and nitric oxide (100 μm). Both CO and NO inhibited respiration, and treatment with Ngb-H64Q-CCC (100 and 50 μm, respectively) significantly reversed this inhibition. These results suggest that Ngb-H64Q-CCC mitigates CO toxicity by scavenging CO from carboxyhemoglobin, improving systemic oxygen delivery and reversing the inhibitory effects of CO on mitochondria. We conclude that Ngb-H64Q-CCC or other CO scavengers demonstrate potential as antidotes that reverse the clinical and molecular effects of CO poisoning.

Direct Two-Minute Unassisted Breathing Evaluation (DTUBE) is an Attractive Alternative to Longer Spontaneous Breathing Trials: A Prospective Observational Study

2017 ◽  
Vol 83 (3) ◽  
pp. 308-313 ◽  
Author(s):  
Matthew B. Bloom ◽  
Jonathan Lu ◽  
Tri Tran ◽  
Marko Bukur ◽  
Rex Chung ◽  
...  
Keyword(s):  
Spontaneous Breathing ◽  
Spontaneous Breathing Trial ◽  
Surgical Intensive Care Unit ◽  
Attractive Alternative ◽  
Surgical Intensive Care ◽  
Minute Period ◽  
Spontaneous Breathing Trials ◽  
Bedside Method ◽  
Simple Bedside ◽  
Successful Extubation

We sought to identify a simple bedside method to predict successful extubation outcomes that might be used during rounds. We hypothesized that a direct 2-minute unassisted breathing evaluation (DTUBE) could replace a longer spontaneous breathing trial (SBT). Data were pro-spectively collected on all patients endotracheally intubated for >48 hours nearing extubation in a tertiary center's mixed trauma/surgical intensive care unit from August 2012 to August 2013. The SBT was performed for at least 30 minutes at 40 per cent FiO2, PEEP 5, and PS 8. DTUBE was performed by physically disconnecting the intubated patient from the ventilator circuit for a 2-minute period of direct observation on room air. Successful extubation was defined freedom from ventilator for greater than 72 hours. Both SBTand DTUBE were performed 128 times, resulting in 90 extubations. The DTUBE correctly predicted success in 75/79 (94.9%) extubations versus 82/89 (92.1%) via SBT. No adverse effects were directly attributed to the DTUBE. The DTUBE is a rapid method of evaluating patients for extubation with prediction accuracy similar to the SBT.

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