Duration Of Preoxygenation Research Articles

Feasibility of quality indicators on prehospital advanced airway management in a physician-staffed emergency medical service: survey-based assessment of the provider point of view

ObjectiveWe aimed to determine the feasibility of quality indicators (QIs) for prehospital advanced airway management (PAAM) from a provider point of view.DesignThe study is a survey based feasibility assessment following...

Synthesis and characterization of novel photochromic and pH-sensitive colorimetric hydrogel based on azobenzene

This article reports the synthesis of new Dye A from the reaction of 4-methyl 2-nitroaniline, NaNO2/H+, and sodium 1-naphtholate. Dye A responded with an obvious colour change visible to naked eyes to pH, ultraviolet light, and fluoride ion and was studied by UV–vis spectroscopy. Next, the reaction of Dye A with crotonic anhydride leads to the formation of MDye A. Subsequently, synthesis of a new type of photochromic and pH-sensitive colorimetric hydrogel consisting of a new azobenzene (MDye A), acrylic acid, acrylamide, N,N'-methylenebisacrylic amide as a crosslinking agent, and sodium acrylate in the presence of 2,2′-azobis(isobutyronitrile) as initiator and sorbitan monostearate (Span 60) as the dispersant or under a LED lamp (400 nm, 20 W) in the presence of CdS nanorods and β-cyclodextrin was studied. The products were characterized using 1H NMR,13C NMR, TGA, DTG, SEM, TEM, and FTIR spectroscopy. The synthesized new hydrogel showed good pH responsiveness and photoresponsiveness, which was investigated by UV–vis spectroscopy. Also, the effects of parameters such as amounts of CdS nanorods, cross-linker, and water, duration of pre-oxygenation, light intensity on the swelling of gel, and polymerization rate in the synthesis of hydrogel were investigated.

227 Impact of Active versus Passive Preoxygenation on Emergency Department Mortality in Kigali, Rwanda

Preoxygenation for endotracheal intubation (EI) is well studied in high-income countries (HIC). However, its effect on emergency department (ED) airway management in low- and middle-income countries (LMIC) is not well characterized. This study compared the impacts of active versus passive preoxygenation methods on ED mortality among patients presenting for emergency care and undergoing EI at the University Teaching Hospital-Kigali (UTH-K). A prospective cohort of patients requiring ED EI, accrued continuously over twelve months (January 1st, 2017 – December 31st, 2017) with documented preoxygenation methods, were evaluated. The exposure of interest was active preoxygenation (defined as bag-valve mask or positive pressure ventilation) versus passive preoxygenation (defined as non-rebreather mask or oxygen facemask). The primary outcome was ED mortality. Collected data included: duration of preoxygenation, EI indication, clinical characteristics, and pre-intubation vital signs. Magnitudes of effects were quantified using multivariable regression models to yield adjusted odds ratios (aOR) with 95% confidence intervals (CI). Of 194 patients undergoing EI, 163 met inclusion and were analyzed. Median age was 38.7 years (IQR 6-84), 72% were male, with 52% trauma patients. Within the cohort, 73.6% received passive preoxygenation while 26.4% were actively preoxygenated. The shock index (SI) was higher than 0.9 in 45% of those with passive preoxygenation and 58.6% of those who were actively preoxygenated. The majority of both passively (68.3%) and actively preoxygenated (53.9%) patients were preoxygenated for 3-5 minutes. Actively preoxygenated patients had higher ED mortality (81.4%) as compared to passively preoxygenated patients (45.8%) (p<0.001). This translated to significantly lower adjusted odds of ED mortality for those with passive preoxygenation in multivariable models controlling for EI indication, pre-intubation oxygen saturation, pre-intubation SI, and intubation method (aOR 0.30, 95% CI: 0.11, 0.82, p=0.02). In adjusted analyses, passively preoxygenated patients had much lower odds of ED mortality. This association could be due to the impacts of active preoxygenation methods or potentially unmeasured confounding factors. Further research is needed to better understand this clinical approach in LMICs where there exists limited data on preoxygenation methods in emergency care and where there are often barriers to oxygen availability.

Preoxygenation: Physiologic Basis, Benefits, and Potential Risks.

Preoxygenation before anesthetic induction and tracheal intubation is a widely accepted maneuver, designed to increase the body oxygen stores and thereby delay the onset of arterial hemoglobin desaturation during apnea. Because difficulties with ventilation and intubation are unpredictable, the need for preoxygenation is desirable in all patients. During emergence from anesthesia, residual effects of anesthetics and inadequate reversal of neuromuscular blockade can lead to hypoventilation, hypoxemia, and loss of airway patency. In accordance, routine preoxygenation before the tracheal extubation has also been recommended. The objective of this article is to discuss the physiologic basis, clinical benefits, and potential concerns about the use of preoxygenation. The effectiveness of preoxygenation is assessed by its efficacy and efficiency. Indices of efficacy include increases in the fraction of alveolar oxygen, increases in arterial oxygen tension, and decreases in the fraction of alveolar nitrogen. End points of maximal preoxygenation (efficacy) are an end-tidal oxygen concentration of 90% or an end-tidal nitrogen concentration of 5%. Efficiency of preoxygenation is reflected in the rate of decline in oxyhemoglobin desaturation during apnea. All investigations have demonstrated that maximal preoxygenation markedly delays arterial hemoglobin desaturation during apnea. This advantage may be blunted in high-risk patients. Various maneuvers have been introduced to extend the effect of preoxygenation. These include elevation of the head, apneic diffusion oxygenation, continuous positive airway pressure (CPAP) and/or positive end-expiratory pressure (PEEP), bilevel positive airway pressure, and transnasal humidified rapid insufflation ventilatory exchange. The benefit of apneic diffusion oxygenation is dependent on achieving maximal preoxygenation, maintaining airway patency, and the existence of a high functional residual capacity to body weight ratio. Potential risks of preoxygenation include delayed detection of esophageal intubation, absorption atelectasis, production of reactive oxygen species, and undesirable hemodynamic effects. Because the duration of preoxygenation is short, the hemodynamic effects and the accumulation of reactive oxygen species are insufficient to negate its benefits. Absorption atelectasis is a consequence of preoxygenation. Two approaches have been proposed to reduce the absorption atelectasis during preoxygenation: a modest decrease in the fraction of inspired oxygen to 0.8, and the use of recruitment maneuvers, such as CPAP, PEEP, and/or a vital capacity maneuver (all of which are commonly performed during the administration of anesthesia). Although a slight decrease in the fraction of inspired oxygen reduces atelectasis, it does so at the expense of a reduction in the protection afforded during apnea.

The Effect of the Duration of Pre-Oxygenation before Endotracheal Suction on Hemodynamic Symptoms

&lt;p&gt;&lt;strong&gt;BACKGROUND:&lt;/strong&gt; Hypoxia and hypoxemia are among the most common complications of endotracheal suctioning. These complications are often mitigated by the administration of oxygen 100% prior to endotracheal suction. Although several studies have supported the application of this method, none have yet specified the exact duration of pre-oxygenation required to be performed before endotracheal suction. The present study was therefore conducted to determine the effect of the duration of pre-oxygenation before endotracheal suction on heart rate and arterial oxygen saturation in patients in intensive care units.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;OBJECTIVES:&lt;/strong&gt; This prospective clinical trial conducted on 63 eligible ICU patients under mechanical ventilator. Subjects randomly divided into three groups. Pre-oxygenation was carried out for 30 seconds in the first group, for one minute in the second group and for two minutes in the third group. All three groups were then hyper-oxygenated for one minute. Arterial oxygen saturation and heart rate were recorded on different occasions in the three groups. The data obtained were analyzed using the ANOVA, the one-way ANOVA, the post-hoc test and the repeated measure ANOVA.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;RESULTS:&lt;/strong&gt; The results obtained showed a greater reduction in the mean O2sat during the suctioning episodes in the 30-second pre-oxygenation group compared to in the one-minute (P=0.046) and two-minute (P=0.001) pre-oxygenation groups. This mean reduction was also observed immediately after suctioning (P=0.001). The mean O2sat was lower in the 30-second pre-oxygenation group than in the one-minute pre-oxygenation group in minutes 5 (P=0.002) and 20 (P=0.001) of the suctioning. Similarly, the mean O2sat was lower in the 30-second pre-oxygenation group than in the two-minute pre-oxygenation group in minutes 5 (P=0.001) and 20 (P=0.001) of the suctioning. The results obtained through the ANOVA showed the lack of significant differences between the three groups in the mean variation in heart rate in the different stages of suctioning.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;CONCLUSIONS:&lt;/strong&gt; According to the results obtained, one-minute and two-minute pre-oxygenations cause less disruption in arterial oxygen saturation compared to a 30-second pre-oxygenation. To achieve stability in arterial oxygen saturation and avoid hypoxemia caused by endotracheal suctioning, one-minute or two-minute pre-oxygenation is recommended in ICUs depending on the patient’s clinical conditions.&lt;/p&gt;

Low-positive pressure ventilation improves non-hypoxaemic apnoea tolerance during ear, nose and throat pan-endoscopy: A randomised controlled trial.

It has been suggested that oxygenation using pressure support ventilation (PSV) before general anaesthesia can reduce the duration of non-hypoxaemic apnoea. The objective was to determine whether or not pre-oxygenation with PSV increases the duration of non-hypoxaemic apnoea in non-obese patients during pan-endoscopy. A randomised, controlled trial. Amiens University Hospital, France. Fifty patients scheduled for ENT pan-endoscopy with a BMI lower than 35 kg m(-2). Patients scheduled for pan-endoscopy were enrolled to receive either 100% oxygen at neutral pressure (the control group) or 100% oxygen with positive-pressure ventilation (a positive inspiratory pressure of 4 cmH2O and a positive end-expiratory pressure of 4 cmH2O; the PSV group) during spontaneous ventilation with a face mask. The goal of pre-oxygenation was to obtain an end-tidal oxygen concentration of more than 90% prior to induction of anaesthesia. The primary efficacy criterion was the duration of non-hypoxaemic apnoea (i.e. before the peripheral capillary oxygen saturation fell to 90%). Secondary outcomes were duration of pre-oxygenation, pre-oxygenation failure and tolerance. The mean (interquartile range) duration of non-hypoxaemic apnoea was longer in the PSV group [598 (447 to 717) s] than in the control group [310 (217 to 451) s] (P < 0.001). Oxygenation time was shorter in the PSV group [190 (159 to 225) s] than in the control group [245 (151 to 435) s] (P = 0.037). Pre-oxygenation was unsuccessful (i.e. end-tidal oxygen concentration was < 90%) in 20% of the patients in the control group but none in the PSV group. The intergroup difference in the duration of pan-endoscopy was not significant. Tolerance was good or very good in all patients. Our results show that pre-oxygenation with PSV is associated with a longer duration of non-hypoxaemic apnoea and a lower frequency of manual reventilation during ENT pan-endoscopy. CLINICALTRIALS. NCT02167334.

Modeling the dynamics of risk of altitude decompression sickness

A probabilistic model of decompression sickness is modified by introducing corrections that determine more precisely the risk of tissue injury by gas bubbles as a function of blood supply and bubble nucleation intensity. Parameters of the “worst” virtual tissues and theoretical curves corresponding to empirical data on the cumulative probability of decompression sickness symptoms for some altitude decompression procedures are determined. The parameters are shown to depend on final pressure, physical load, and duration of preoxygenation.

Study of the safe threshold of apneic period in children during anesthesia induction

Study Objectives: (1) To investigate changes in arterial oxygen saturation via pulse oximeter (SpO 2) during apnea and after reinstitution of manual ventilation at SpO 2 of 95% or 90% following rapid sequence induction of anesthesia in children after 2-minute preoxygenation; (2) to determine whether the setting of a safe threshold of apneic period to an SpO 2 of 95% is appropriate in children during anesthetic induction; and (3) to evaluate the influences of age, body weight, and height on the time from the start of apnea to SpO 2 of 95%. Design: A clinical study of random design and comparison among groups. Setting: Operating room of a plastic surgery hospital of the Chinese Academy of Medical Sciences and Peking Union Medical College. Patients: 152 infants and children, ASA physical status I, aged 3 months to 12 years, scheduled for elective plastic surgery. Interventions: Patients were divided into three age groups: Group 1-infants 3 months to 1 year (n = 39); Group 2-children 1 to 3 years (n = 41); and Group 3-children 3 to 12 years (n = 72). Patients in each age group were randomly allocated again to Subgroups A and B. After a 2-minute preoxygenation, anesthesia was induced with thiopental 5 mg/kg, fentanyl 5 μg/kg, and suxamethonium 1.5 mg/kg. Patients were manually ventilated when SpO 2 decreased to 90% in Subgroups A and 95% in Subgroups B, respectively, during apnea. Measurements and Main Results: SpO 2 was measured continuously with a Datex pulse oximeter applied to the right index finger. During apnea, the times for SpO 2 to decrease to 99% (T 99) and 95% (T 95) in all children, and 90% (T 90) in Subgroups A were recorded. The time for SpO 2 to decrease from 95% to 90% (T 95 − 90) in Subgroups A was also measured. After reinstitution of manual ventilation, the time when SpO 2 continued to decrease (T 1) and the time from the end of apnea to recovery of SpO 2 baseline (T 2) were determined. In addition, the lowest value of SpO 2 after apnea was also recorded. The results showed that younger children were more susceptible than older children to the risk of hypoxemia during apnea. There were significant differences in T 99, T 95, T 90, and T 95 − 90 between the three age groups. T 1 and T 2 were significantly longer in Group 3 than in Groups 1 and 2. There were significant differences in the lowest values of SpO 2 following apnea among the three Subgroups A and between Subgroups A and B of each age group. During apnea, heart rate decreased gradually as SpO 2 decreased, showing a significant decrease at SpO 2 of 95%. Bradycardia was found in three children in Subgroups A. The apnea time to SpO 2 of 95% correlated well with age, weight, and height by linear regression analysis. Conclusions: The safe threshold of an apneic period setting to an SpO 2 of 95% was appropriate in children during anesthesia induction. Despite the same duration of preoxygenation, younger children were more susceptible than older ones to the risk of hypoxemia during apnea. The apnea time to Sp0 2 of 95% correlated with age, body weight, and height using linear regression analysis.

Study of Optimal Duration of Preoxygenation in Children

Study of Optimal Duration of Preoxygenation in Children

Study of the optimal duration of preoxygenation in children

Study of the optimal duration of preoxygenation in children

The Duration of Preoxygenation in Patients with Normal and Impaired Pulmonary Function

The Duration of Preoxygenation in Patients with Normal and Impaired Pulmonary Function