Changes In FiO2 Research Articles

Oxygenation associated with cord management strategies among preterm infants

Compare changes in SpO2 and FiO2 post-birth among preterm infants after delayed cord clamping (DCC), umbilical cord milking (UCM) or early cord clamping (ECC). Retrospective study of infants <32 weeks gestation born between 2014 and 2021. ECC was clamping 0-59 s, DCC was clamping ≥60 s after delivery, UCM defined as milking the intact umbilical cord several times before clamping. Of 463 infants; 257 received DCC, 168 received UCM, 38 received ECC. UCM infants had higher median SpO2 values at 4-(79% UCM vs 69% DCC, p = 0.027) and 5-(85% UCM vs 80% DCC, p = 0.023) minutes after-birth compared to DCC. DCC and UCM infants required lower FiO2 levels in the first 5-minutes compared to ECC infants (DCC 0.38 ± 0.17, UCM 0.40 ± 0.20 vs ECC 0.51 ± 0.27, p's <0.001). The proportion of infants achieving SpO2 ≥ 80% by 5 min was similar in all groups, FiO2 needed to achieve this goal was higher in ECC infants.

Influence of Fractional Inspired Oxygen Tension on Lung Perfusion Distribution, Regional Ventilation, and Lung Volume during Mechanical Ventilation of Supine Healthy Swine.

Lower fractional inspired oxygen tension (Fio2) during general anesthesia can reduce lung atelectasis. The objectives are to evaluate the effect of two Fio2 (0.4 and 1) during low positive end-expiratory pressure (PEEP) ventilation over lung perfusion distribution, volume, and regional ventilation. These variables were evaluated at two PEEP levels and unilateral lung atelectasis. In this exploratory study, 10 healthy female piglets (32.3 ± 3.4 kg) underwent mechanical ventilation in two atelectasis models: (1) bilateral gravitational atelectasis (n = 6), induced by changes in PEEP and Fio2 in three combinations: high PEEP with low Fio2 (Fio2 = 0.4), zero PEEP (PEEP0) with low Fio2 (Fio2 = 0.4), and PEEP0 with high Fio2 (Fio2 = 1); and (2) unilateral atelectasis (n = 6), induced by left bronchial occlusion, with the left lung aerated (Fio2 = 0.21) and low aerated (Fio2 = 1; n = 5 for this step). Measurements were conducted after 10 min in each step, encompassing assessment of respiratory mechanics, oxygenation, and hemodynamics; lung ventilation and perfusion by electrical impedance tomography; and lung aeration and perfusion by computed tomography. During bilateral gravitational atelectasis, PEEP reduction increased atelectasis in dorsal regions, decreased respiratory compliance, and distributed lung ventilation to ventral regions with a parallel shift of perfusion to the same areas. With PEEP0, there were no differences between low and high Fio2 in respiratory compliance (23.9 ± 6.5 ml/cm H2O vs. 21.9 ± 5.0; P = 0.441), regional ventilation, and regional perfusion, despite higher lung collapse (18.6 ± 7.6% vs. 32.7 ± 14.5%; P = 0.045) with high Fio2. During unilateral lung atelectasis, the deaerated lung had a lower shunt (19.3 ± 3.6% vs. 25.3 ± 5.5%; P = 0.045) and lower computed tomography perfusion to the left lung (8.8 ± 1.8% vs. 23.8 ± 7.1%; P = 0.007). PEEP0 with low Fio2, compared with high Fio2, did not produce significant changes in respiratory system compliance, regional lung ventilation, and perfusion despite significantly lower lung collapse. After left bronchial occlusion, the shrinkage of the parenchyma with Fio2 = 1 enhanced hypoxic pulmonary vasoconstriction, reducing intrapulmonary shunt and perfusion of the nonventilated areas.

Long-distance transfer of unwell neonates: A case series.

The Northern Territory Neonatal Emergency Transport Service (NETS NT) pilot was created in April 2018 to expedite the transfer of critically unwell neonates to specialised interstate centres. The aim of this paper is to describe long-distance retrievals undertaken during the first 3 years of operation of the service. A case series is described comprising neonates requiring long-distance aeromedical transfer (>2500 km) by NETS NT between April 2018 and June 2021. Data were obtained from hospital and transport service documentation. This was supplemented by four semi-structured interviews with transport staff. Thirty neonates were transferred via NETS NT during the investigation period, including 19 transfers >2500 km. Of these, 18/19 (94.7%) required respiratory support, 8/19 (42.1%) were intubated and 4/19 (21.1%) required inotropic support. The average length of transport was 7.5 h (5.6-8.9). Twelve patients had in-flight documentation available. Eight required increased oxygen administration 8/12 (66.6%). The median change in FiO2 was an increase of 0.02 (-0.05 to 0.45). The NETS NT has been successfully established to transport high-risk neonates to interstate quaternary health services when required. Future recommendations for the service include ongoing implementation of systems and processes to strengthen all aspects of governance and operations using suitably adapted resources from established Australian retrievals services.

Haemodynamic changes during prone versus supine position in patients with COVID-19 acute respiratory distress syndrome

BackgroundProne positioning improves oxygenation in patients with acute respiratory distress syndrome (ARDS) secondary to COVID-19. However, its haemodynamic effects are poorly understood. ObjectivesThe objective of this study was to investigate the acute haemodynamic changes associated with prone position in mechanically ventilated patients with COVID-19 ARDS. The primary objective was to describe changes in cardiac index with prone position. The secondary objectives were to describe changes in mean arterial pressure, FiO2, PaO2/FiO2 ratio, and oxygen delivery (DO2) with prone position. MethodsWe performed this cohort-embedded study in an Australian intensive care unit, between September and November 2021. We included adult patients with severe COVID-19 ARDS, requiring mechanical ventilation and prone positioning for respiratory failure. We placed patients in the prone position for 16 h per session. Using pulse contour technology, we collected haemodynamic data every 5 min for 2 h in the supine position and for 2 h in the prone position consecutively. ResultsWe studied 18 patients. Cardiac index, stroke volume index, and mean arterial pressure increased significantly in the prone position compared to supine position. The mean cardiac index was higher in the prone group than in the supine group by 0.44 L/min/m2 (95% confidence interval, 0.24 to 0.63) (P < 0.001). FiO2 requirement decreased significantly in the prone position (P < 0.001), with a significant increase in PaO2/FiO2 ratio (P < 0.001). DO2 also increased significantly in the prone position, from a median DO2 of 597 mls O2/min (interquartile range, 504 to 931) in the supine position to 743 mls O2/min (interquartile range, 604 to 1075) in the prone position (P < 0.001). ConclusionProne position increased the cardiac index, mean arterial pressure, and DO2 in invasively ventilated patients with COVID-19 ARDS. These changes may contribute to improved tissue oxygenation and improved outcomes observed in trials of prone positioning.

Effects of changes in inspired oxygen fraction on urinary oxygen tension measurements

BackgroundContinuous measurement of urinary PO2 (PuO2) is being applied to indirectly monitor renal medullary PO2. However, when applied to critically ill patients with shock, its measurement may be affected by changes in FiO2 and PaO2 and potential associated O2 diffusion between urine and ureteric or bladder tissue. We aimed to investigate PuO2 measurements in septic shock patients with a fiberoptic luminescence optode inserted into the urinary catheter lumen in relation to episodes of FiO2 change. We also evaluated medullary and urinary oxygen tension values in Merino ewes at two different FiO2 levels.ResultsIn 10 human patients, there were 32 FiO2 decreases and 31 increases in FiO2. Median pre-decrease FiO2 was 0.36 [0.30, 0.39] and median post-decrease FiO2 was 0.30 [0.23, 0.30], p = 0.006. PaO2 levels decreased from 83 mmHg [77, 94] to 72 [62, 80] mmHg, p = 0.009. However, PuO2 was 23.2 mmHg [20.5, 29.0] before and 24.2 mmHg [20.6, 26.3] after the intervention (p = 0.56). The median pre-increase FiO2 was 0.30 [0.21, 0.30] and median post-increase FiO2 was 0.35 [0.30, 0.40], p = 0.008. PaO2 levels increased from 64 mmHg [58, 72 mmHg] to 71 mmHg [70, 100], p = 0.04. However, PuO2 was 25.0 mmHg [IQR: 20.7, 26.8] before and 24.3 mmHg [IQR: 20.7, 26.3] after the intervention (p = 0.65). A mixed linear regression model showed a weak correlation between the variation in PaO2 and the variation in PuO2 values. In 9 Merino ewes, when comparing oxygen tension levels between FiO2 of 0.21 and 0.40, medullary values did not differ (25.1 ± 13.4 mmHg vs. 27.9 ± 15.4 mmHg, respectively, p = 0.6766) and this was similar to urinary oxygen values (27.1 ± 6.17 mmHg vs. 29.7 ± 4.41 mmHg, respectively, p = 0.3192).ConclusionsChanges in FiO2 and PaO2 within the context of usual care did not affect PuO2. Our findings were supported by experimental data and suggest that PuO2 can be used as biomarker of medullary oxygenation irrespective of FiO2.

Response categorization and outcomes in extremely premature infants born at 22-26 weeks gestation that received inhaled nitric oxide for hypoxic respiratory failure.

To evaluate the outcomes of extremely premature infants who received inhaled nitric oxide(iNO) for hypoxic respiratory failure(HRF). Retrospective analysis of 107 infants born 22-26 weeks gestation who received iNO for HRF at a single institution. Infants were categorized as positive, negative, or no responders based on change in FiO2 or OI. Underlying physiology was determined using Echocardiography/Radiography/Biochemistry. 63% of infants had a positive response; they received iNO earlier and were more likely to have acute pulmonary hypertension(PH). Positive response correlated with decreased incidence of death or grade 3 BPD at 36 weeks postmenstrual age, as compared to a negative response. Extremely premature infants have a positive response rate to iNO comparable to term infants when used for PH in the transitional period. Infants with a negative response to iNO had worse outcomes, necessitating the determination of the underlying physiology of HRF prior to iNO initiation.

The Impact of Breathing Hypoxic Gas and Oxygen on Pulmonary Hemodynamics in Patients With Pulmonary Hypertension

BackgroundPure oxygen breathing (hyperoxia) may improve hemodynamics in patients with pulmonary hypertension (PH) and allows to calculate right-to-left shunt fraction (Qs/Qt), whereas breathing normobaric hypoxia may accelerate hypoxic pulmonary vasoconstriction (HPV). This study investigates how hyperoxia and hypoxia affect mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) in patients with PH and whether Qs/Qt influences the changes of mPAP and PVR.Study Design and MethodsAdults with pulmonary arterial or chronic thromboembolic PH (PAH/CTEPH) underwent repetitive hemodynamic and blood gas measurements during right heart catheterization (RHC) under normoxia [fractions of inspiratory oxygen (FiO2) 0.21], hypoxia (FiO2 0.15), and hyperoxia (FiO2 1.0) for at least 10 min.ResultsWe included 149 patients (79/70 PAH/CTEPH, 59% women, mean ± SD 60 ± 17 years). Multivariable regressions (mean change, CI) showed that hypoxia did not affect mPAP and cardiac index, but increased PVR [0.4 (0.1–0.7) WU, p = 0.021] due to decreased pulmonary artery wedge pressure [−0.54 (−0.92 to −0.162), p = 0.005]. Hyperoxia significantly decreased mPAP [−4.4 (−5.5 to −3.3) mmHg, p < 0.001] and PVR [−0.4 (−0.7 to −0.1) WU, p = 0.006] compared with normoxia. The Qs/Qt (14 ± 6%) was >10 in 75% of subjects but changes of mPAP and PVR under hyperoxia and hypoxia were independent of Qs/Qt.ConclusionAcute exposure to hypoxia did not relevantly alter pulmonary hemodynamics indicating a blunted HPV-response in PH. In contrast, hyperoxia remarkably reduced mPAP and PVR, indicating a preserved vasodilator response to oxygen and possibly supporting the oxygen therapy in patients with PH. A high proportion of patients with PH showed increased Qs/Qt, which, however, was not associated with changes in pulmonary hemodynamics in response to changes in FiO2.

The Acute Effect of Packed Red Blood Cell Transfusion in Mechanically Ventilated Children after the Norwood Operation.

Packed red blood cell (PRBC) transfusions are commonly administered in pediatric patients following the Norwood operation. This study was conducted to determine the effect of PRBC transfusions on hemodynamic parameters in pediatric patients with single-ventricle physiology and parallel circulation. A single-center, retrospective chart review was conducted. Pediatric patients admitted to the cardiac intensive care unit after Norwood operation between 2017 and 2018 were identified. Hemodynamic parameters were collected within a four-hour period before and after a PRBC transfusion. Univariate analyses using paired t tests were conducted to compare blood gas values before and after PRBC transfusion. Next, multivariate regression analyses were conducted to model the impact of transfusion volume, change in hemoglobin levels, and change in FiO2 on the change in PaO2 and PaCO2. These analyses included data from 33 eligible patients who received a PRBC transfusion following a Norwood operation. The hemoglobin levels (p < 0.01) and the PaO2/FiO2 ratio (p = 0.04) were significantly increased, while arterial lactate levels (p = 0.03) were significantly decreased following the transfusion. Transfusion for a pre-transfusion hemoglobin of 12.4g/dL appears to provide greatest reduction in lactate, used as a surrogate marker for systemic oxygen delivery. No significant changes were found in arterial pH, PaO2, and PaCO2. PRBC transfusions following the Norwood operation may be a useful intervention to increase systemic oxygen delivery, improving PaO2/FiO2 ratio and improving serum lactate. The benefits of PRBC transfusions must be weighed against previously identified risks on a patient-specific basis. Further studies are warranted to further delineate the effects of such transfusions in this population.

Effect of changes in inspired oxygen fraction on oxygen delivery during cardiac surgery: a substudy of the CARROT trial

When hemoglobin (Hb) is fully saturated with oxygen, the additional gain in oxygen delivery (DO2) achieved by increasing the fraction of inspired oxygen (FiO2) is often considered clinically insignificant. In this study, we evaluated the change in DO2, interrogated by mixed venous oxygen saturation (SvO2), in response to a change in FiO2 of 0.5 during cardiac surgery. When patients were hemodynamically stable, FiO2 was alternated between 0.5 and 1.0 in on-pump cardiac surgery patients (pilot study), and between 0.3 and 0.8 in off-pump coronary artery bypass grafting patients (substudy of the CARROT trial). After the patient had stabilized, a blood gas analysis was performed to measure SvO2. The observed change in SvO2 (ΔSvO2) was compared to the expected ΔSvO2 calculated using Fick’s equation. A total 106 changes in FiO2 (two changes per patient; total 53 patients; on-pump, n = 36; off-pump, n = 17) were finally analyzed. While Hb saturation remained near 100% (on-pump, 100%; off-pump, mean [SD] = 98.1% [1.5] when FiO2 was 0.3 and 99.9% [0.2] when FiO2 was 0.8), SvO2 changed significantly as FiO2 was changed (the first and second changes in on-pump, 7.7%p [3.8] and 7.6%p [3.5], respectively; off-pump, 7.9%p [4.9] and 6.2%p [3.9]; all P < 0.001). As a total, regardless of the surgery type, the observed ΔSvO2 after the FiO2 change of 0.5 was ≥ 5%p in 82 (77.4%) changes and ≥ 10%p in 31 (29.2%) changes (mean [SD], 7.5%p [3.9]). Hb concentration was not correlated with the observed ΔSvO2 (the first changes, r = − 0.06, P = 0.677; the second changes, r = − 0.21, P = 0.138). The mean (SD) residual ΔSvO2 (observed − expected ΔSvO2) was 0%p (4). Residual ΔSvO2 was more than 5%p in 14 (13.2%) changes and exceeded 10%p in 2 (1.9%) changes. Residual ΔSvO2 was greater in patients with chronic kidney disease than in those without (median [IQR], 5%p [0 to 7] vs. 0%p [− 3 to 2]; P = 0.049). DO2, interrogated by SvO2, may increase to a clinically significant degree as FiO2 is increased during cardiac surgery, and the increase of SvO2 is not related to Hb concentration. SvO2 increases more than expected in patients with chronic kidney disease. Increasing FiO2 can be used to increase DO2 during cardiac surgery.

Use of Low-Flow Flowmeter to Titrate the FiO2 Delivered in Neonatal Resuscitation

Introduction: The oxygen concentration used in neonatal resuscitation has been a matter of debate with higher oxygen concentrations posing many adverse outcomes. Recent guidelines recommend use of blender to titrate FiO2 delivered during resuscitation. However, blender being unaffordable and unavailable at many peripheral institutions, we tried to use a low-flow flowmeter to titrate the oxygen and measure FiO2 delivered at different flow rates. Methods: From a central oxygen supply, oxygen flow was titrated using a low-flow flowmeter which was connected to a self-inflating bag and oximeter. Three variables were taken—volume of self-inflating bag, flow rate, and number of compressions per minute. FiO2 delivered with each variable, keeping the other two constant, was recorded. Results: The data obtained was analyzed by fitting the study variables into a stepwise multiple linear regression model and a linear equation was obtained. The model R square obtained suggested strong linear relationship between flow rate and FiO2 delivered. The model showed statistically significant association between flow rate and FiO2 delivery, whereas association with other variables was statistically insignificant. Discussion: Our study suggests that 76.57% of change in FiO2 is determined by change in flow rate. The major advantage of this study would be at resource poor settings where a low-flow flowmeter which is more cost effective can be used to titrate the FiO2 delivered during neonatal resuscitation.

Knobmanship: Dialing Up Understanding of VAE Triggers

Background: Mechanical ventilation is a lifesaving therapy for critically ill patients. Hospitals perform surveillance for the NHSN for ventilator-associated events (VAE) by monitoring mechanically ventilated patients for metrics that are generally thought to be objective and preventable and that lead to poor patient outcomes. The VAE definition is met in a stepwise manner; initially, a ventilator-associated condition (VAC) is triggered with an increase in positive end-expiratory pressure (PEEP, &gt;3 cm H2O) or fraction of inspired oxygen (FIO2, 0.20 or 20 points) after a period of stability or improvement on the ventilator. We believe that many reported VAEs could be avoided by provider and respiratory therapy attention to “knobmanship.” We define knobmanship as knowledge of the VAE definition and trigger points combined with appropriate clinical care for mechanically ventilated patients while avoiding unnecessary triggering of the VAE definition by avoiding small unneeded changes in PEEP or FIO2. Methods: We performed a chart review of 283 patients who had a reported VAE to the NHSN between January 1, 2019, and December 31, 2020. We collected data including type of VAE, VAE triggering criteria, and clinical course. Results: Of the 283 VAEs, 59 were triggered by a PEEP increase from 5 to 8 with stable or decreasing FIO2. Of the 59 VAEs, 33 were VACs, 18 were infection-related ventilator- associated complications (IVACs), and 8 were possible ventilator-associated pneumonia (PVAP). Most of these transient changes in PEEP were deemed clinically unnecessary. A 21% reduction of VAEs reported to the NSHN over the 2-year review period could have been avoided by knobmanship. Conclusions: The VAE definition may often be triggered by provider bias to the ventilator settings rather than what the patient’s clinical-condition requires. Attention to knobmanship may result in substantial decrease in reported VAE.Funding: NoDisclosures: None

Continuous and intermittent administration of intravenous sildenafil in critically ill infants with pulmonary hypertension.

We retrospectively evaluated subjects less than 12 months old treated with IV sildenafil for PH. Vital signs, oxygen requirement, vasoactive-inotropic score (VIS), and echocardiogram results before and after sildenafil initiation, and the need for discontinuation due to side effects, were noted. Forty-three subjects were identified (23 continuous, 20 intermittent). There were clinically significant differences in PH classifications between groups. The continuous group was significantly younger (p = 0.010) with higher baseline severity of illness suggested by higher inspired oxygen (FiO2 ) and VIS (p = 0.012). After sildenafil initiation, there were no significant differences in changes in blood pressure, oxygen saturation, FiO2 , or VIS between groups, and no difference in the number of subjects requiring discontinuation due to side effects (4 continuous, 1 intermittent, p = 0.351). Eight continuous group subjects (34.8%) and 3 intermittent group subjects (15.0%) died (p = 0.024), but echocardiographic improvement in PH degree was more common in the continuous group (77.8% vs. 33.3%, p = 0.007). In this small cohort of infants treated with continuous or intermittent IV sildenafil, in the setting of different baseline characteristics between groups, there were no significant differences in changes in vital signs, VIS, FiO2 , or need for discontinuation of therapy due to side effects. Higher continuous group mortality may be explained by greater baseline illness severity, but larger prospective, randomized studies are required to investigate these different delivery methods.

Patient vital signs in relation to ICU admission in treatment of acute leukemia: a retrospective chart review

ABSTRACT Objectives The objective of the current study was to investigate the relationship between changes in vital signs and intensive care unit (ICU) admission. Windsor Regional Hospital treats 15–20 new patients a year with acute leukemia. These patients are at increased risk of neutropenic fevers and admission to the ICU following induction chemotherapy. Methods Retrospective review examined the correlation between acute leukemia patient vitals and ICU admission. The analysis included 37 patients: 7 ICU versus 30 controls. Changes were compared to baseline over 24 hours prior to ICU admission or 5 days after the initiation of induction chemotherapy in the following vital signs: heart rate (HR), mean arterial pressure (MAP), temperature (T), respiratory rate (RR), and fraction of inspired oxygen (FiO2) required to maintain a stable oxygen saturation. Results RR and FiO2 demonstrated significant change over baseline leading up to ICU admission within the ICU group. T, HR and MAP did not demonstrate significant changes over time in either group. RR, FiO2 and HR were significantly higher in the ICU group at time zero compared with the control group. RR was recorded least frequently in the 24 hours leading up to ICU admission. Discussion Changes in RR and FiO2 predicted clinical deterioration requiring ICU admission in acute leukemia patients. This is consistent with the predominant reason for ICU admission which was respiratory failure. Conclusion We present preliminary evidence to support enhanced monitoring of RR and FiO2 in acute leukemia patients following induction chemotherapy with early intervention if identified.

Comparison of oxygenation and ventilation parameters between proseal laryngeal mask airway and endotracheal tube in patients undergoing laparoscopic surgeries: a prospective observational study

Introduction: Use of endotracheal tube (ETT) has many limitations. There is a need for an airway device with similar safety and good side effect profile. In this prospective observational study, the oxygenation and ventilation parameters between patients who were inserted Proseal laryngeal mask airway (PLMA) or ETT for laparoscopic surgeries were compared. Materials and Methods: After ethical committee approval, informed consent was obtained from sixty patients (thirty in each group) posted for elective laparoscopic surgery. Following induction of general anaesthesia and paralysis, PLMA or ETT was inserted and pressure control mode was used for ventilation. The following parameters were measured: a. Oxygen saturation and changes in FiO2 needed to ensure a target SpO2> 95%, EtCO2 and changes in respiratory rate and inspiratory pressure needed to ensure a target EtCO2 between 35-45 mmHg. b. Insertion characteristics of airway device and gastric tube, hemodynamic responses, incidence of complications. Statistical Analysis: Chi-square test was used to analyze qualitative data. Independent t test was used to assess quantitative variables. Repeated measures ANOVA was used to compare the outcome measures over time adjusted for duration of surgery and anaesthesia. P values Results: Both groups were comparable with respect to age, gender and weight. Oxygenation and ventilation parameters achieved with both ETT and PLMA were comparable and satisfactory. Haemodynamic parameters increased significantly in ETT group compared to PLMA group during airway insertion and removal. Also, postoperative sore throat was comparatively less in the PLMA group. Conclusion: Hence we conclude that PLMA may be considered as an alternative to ETT in airway management of patients undergoing laparoscopic surgeries with comparable oxygenation and ventilation parameters and improved side effect profile. Keywords: Endotracheal tube, Proseal laryngeal mask airway, Laryngoscopy, Pneumoperitoneum.

Espectro clínico da infecção por COVID-19 nos organismos humanos: revisão bibliográfica

Objetivo: Analisar através de uma revisão as apresentações clínicas mais relevantes da infecção pelo SARS-CoV-2. Revisão Bibliográfica: O COVID-19 possui um espectro amplo de apresentações. A forma assintomática é um desafio diagnóstico, levando à subnotificação. Acredita-se que ocorram em indivíduos com eficiente defesa antiviral e resposta imune efetiva, mas incapazes de bloquear completamente o vírus. A Síndrome Gripal Leve representa 80% dos casos sintomáticos, manifestados através de febre, tosse, fadiga, dispneia e mialgia. Os casos graves, de 5-10% dos sintomáticos, geralmente se expressam por pneumonia, com alterações de sinais vitais, dispneia ou disfunção orgânica; além disso, podem evoluir para uma Síndrome do Desconforto Respiratório Agudo, com complicações respiratórias, alterações radiográficas e da PaO2/FiO2. A Sepse e Choque séptico por COVID-19 possuem ainda maior chance de desfecho desfavorável, condições que indicam permanência do paciente em ambiente de terapia intensiva. Considerações Finais: Pouco ainda se sabe sobre o COVID-19, mas seu alto potencial de transmissibilidade e sua variabilidade de apresentações clínicas são reconhecidos como fatores complicadores do controle da epidemia.

Ventilator-associated Events in Children: Controversies and Research Needs.

Ventilator-associated Events in Children: Controversies and Research Needs.

Arterial oxygen tensions in mechanically ventilated ICU patients and mortality: a retrospective, multicentre, observational cohort study

BackgroundSupplemental oxygen therapy is commonly required for respiratory failure requiring mechanical ventilation in the ICU. However, hyperoxaemia may be injurious and may increase mortality. We evaluated the relationship amongst the degree of hyperoxaemia and changes in fraction of inspired oxygen (Fio2) in response to hyperoxaemia, as well as associations with mortality in mechanically ventilated ICU patients. MethodsWe retrospectively identified all invasively mechanically ventilated patients admitted to five ICUs, and retrieved all oxygen tension (Pao2) and Fio2 data. We assessed the time between arterial blood gas (ABG) samples, proportions of patients with hyperoxaemia, and changes in Fio2 when hyperoxaemia was present. The primary outcome was the association between Pao2 (assessed by mechanically ventilated exposure-time-divided area under the curve [AUC]) and mortality (in-ICU and post-ICU discharge) using a multistate illness–death model with transition intensities estimated by Cox proportional hazards models. ResultsWe assessed 177 769 ABG analyses obtained from 4998 patients between January 2012 and June 2016. The median time between ABGs was 3 h (inter-quartile range: 2–4 h); the median Pao2 was 11.3 kPa (9.8–13.6 kPa), and Fio2 was 0.40 (0.35–0.50). Hyperoxaemia (Pao2 >13.7 kPa) was present in 23.9% of the ABGs, and hyperoxaemia seemed to be disregarded when Fio2 was <0.40, as >50% of these Fio2 values were not subsequently reduced. AUC Pao2 >16.0 kPa was associated with increased ICU mortality (adjusted hazard ratio: 1.75; 95% confidence interval: 1.28–2.40). ConclusionsIn mechanically ventilated ICU patients, hyperoxaemia was common. Although oxygen supplementation was often reduced when hyperoxaemia was observed, several patients remained hyperoxaemic. Hyperoxaemia was associated with increased ICU mortality in these patients.

Measurement above the carina of FiO2 and Positive Pressure changes using different HFNO rates.

Measurement above the carina of FiO2 and Positive Pressure changes using different HFNO rates.

Role of lung ultrasound in the assessment of recruitment maneuvers in ventilated preterm neonates with respiratory distress syndrome and its correlation with tracheal IL-6 levels: A randomized controlled trial.

This study's aim is to evaluate lung ultrasound (LUS) efficacy in detecting opening and closing lung pressures and its correlation with the tracheal interleukin 6 (IL-6) level. This single-blinded randomized controlled study was done at Ain Shams University Children's Hospital neonatal intensive care units, Egypt. It consists of 44 mechanically ventilated preterm neonates with Respiratory Distress Syndrome (RDS). Initial LUS assessment was done followed by randomization to one of 2 groups; group I: 22 patients underwent LUS guided RM and group II: 22 patients underwent non-ultrasound guided RM. Tracheal IL-6 level was measured before and after RM in both groups. The LUS scores showed a sensitivity of 86.7%, specificity of 62.10% and accuracy of 70.45% at the cut-off point >B1 grade. After RM, there was a higher percentage of changes in mean airway pressure (p = 0.03), FiO2 (p = 0.01), PaO2/FiO2 ratio (p = 0.01), and IL-6 (p < 0.01) in group I. The duration of oxygen requirement (6 vs.13.5 days, p = 0.01), invasive ventilation (3 vs.5.5 days, p = 0.03), non-invasive ventilation (2.5 vs. 5 days, p = 0.02) and NICU stay (21.5 vs. 42.5 days, p = 0.03) were less in group I. A positive correlation is found between reaeration score and the duration of O2 requirement (p = 0.002), duration of invasive ventilation (p = 0.001), NICU length of stay (p = 0.002) and negative correlation with PaO2/FiO2 ratio before RM (p = 0.012). The best cut-off point for the reaeration score is >21 with a sensitivity of 75%, specificity of 71.43% and area under the curve of 78.1%. LUS-guided RM achieved earlier lowest FiO2, shorter O2 dependency, lesser NICU stay and marked decrease in lung inflammation by decreasing atelectotrauma and shortening the duration of invasive ventilation.

Predictive validity of a novel non-invasive estimation of effective shunt fraction in critically ill patients

BackgroundAccurate measurement of pulmonary oxygenation is important for classification of disease severity and quantification of outcomes in clinical studies. Currently, tension-based methods such as P/F ratio are in widespread use, but are known to be less accurate than content-based methods. However, content-based methods require invasive measurements or sophisticated equipment that are rarely used in clinical practice. We devised two new methods to infer shunt fraction from a single arterial blood gas sample: (1) a non-invasive effective shunt (ES) fraction calculated using a rearrangement of the indirect Fick equation, standard constants, and a procedural inversion of the relationship between content and tension and (2) inferred values from a database of outputs from an integrated mathematical model of gas exchange (DB). We compared the predictive validity—the accuracy of predictions of PaO2 following changes in FIO2—of each measure in a retrospective database of 78,159 arterial blood gas (ABG) results from critically ill patients.ResultsIn a formal test set comprising 9,635 pairs of ABGs, the median absolute error (MAE) values for the four measures were as follows: alveolar-arterial difference, 7.30 kPa; PaO2/FIO2 ratio, 2.41 kPa; DB, 2.13 kPa; and ES, 1.88 kPa. ES performed significantly better than other measures (p < 10-10 in all comparisons). Further exploration of the DB method demonstrated that obtaining two blood gas measurements at different FIO2 provides a more precise description of pulmonary oxygenation.ConclusionsEffective shunt can be calculated using a computationally efficient procedure using routinely collected arterial blood gas data and has better predictive validity than other analytic methods. For practical assessment of oxygenation in clinical research, ES should be used in preference to other indices. ES can be calculated at http://baillielab.net/es.