Hypoxemia and its clinical predictors among children with respiratory distress admitted to the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia.

INTRODUCTION: Hypoxemia is a common complication of childhood respiratory tract infections and non-respiratory infections. Hypoxemic children have a five-fold increased risk of death compared to children without hypoxemia. In addition, there is limited evidence about hypoxemia and clinical predictors in Ethiopia. Therefore, this study was conducted to assess the prevalence and clinical predictors of hypoxemia among children with respiratory distress admitted to the University of Gondar Comprehensive Specialized Hospital. METHODS: An institutional-based cross-sectional study was conducted from December 2020 to May 2021 in northwest Ethiopia. A total of 399 study participants were selected using systematic random sampling. The oxygen saturation of the child was measured using Masimo rad-5 pulse oximetry. SPSS version 21 software was used for statistical analysis. RESULT: In this study, the prevalence of hypoxemia among children with respiratory distress was 63.5%. The clinical signs and symptoms significantly associated with hypoxemia were: head-nodding (AOR: 4.1, 95% CI: 1.81-9.28) and chest indrawing (AOR: 3.08, 95% CI: 1.32-7.16) which were considered statistically the risk factors for hypoxemia while inability to feed (AOR: 0.13, 95% CI: 0.02-0.77) was the protective factor for hypoxemia. The most sensitive predictors of hypoxemia were fast breathing with sensitivity (98.4%), nasal flaring (100.0%), chest indrawing (83.6%), and intercostal retraction (93.1%). The best specific predictors of hypoxemia were breathing difficulty with specificity (79.4%), inability to feed (100.0%), wheezing (83.0%), cyanosis (98.6%), impaired consciousness (94.2%), head-nodding (88.7%), and supra-sternal retraction (96.5%). CONCLUSION AND RECOMMENDATION: The prevalence of hypoxemia among children was high. The predictors of hypoxemia were the inability to feed, head nodding, and chest indrawing. It is recommended that the health care settings provide immediate care for the children with an inability to feed, head nodding, and chest indrawing. The policymakers better to focus on preventive strategies, particularly those with the most specific clinical predictors.

Place of high-flow nasal oxygen in nonoperating room anesthesia.

PURPOSE OF REVIEW: This article aims to assess the utility of high-flow nasal oxygen (HFNO) therapy in nonoperating room anesthesia (NORA) settings. RECENT FINDINGS: The number of procedural interventions under deep sedation in NORA is still increasing. Administration of oxygen is recommended to prevent hypoxemia and is usually delivered with standard oxygen through nasal cannula or a face mask. HFNO is a simple alternative with a high warmed humidified flow (ranging from 30 to 70 l/min) with a precise fraction inspired of oxygen (ranging from 21 to 100%). Compared to standard oxygen, HFNO has demonstrated efficacy in reducing the incidence of hypoxemia and the need for airway maneuvers. Research on HFNO has primarily focused on its application in gastrointestinal endoscopy procedures. Yet, it has also shown promising results in various other procedural interventions including bronchoscopy, cardiology, and endovascular procedures. However, the adoption of HFNO prompted considerations regarding cost-effectiveness and environmental impact. SUMMARY: HFNO emerges as a compelling alternative to conventional oxygen delivery methods for preventing hypoxemia during procedural interventions in NORA. However, its utilization should be reserved for patients at moderate-to-high risk to mitigate the impact of cost and environmental factors.

Addition of Mask to High-flow Nasal Oxygen: A Strategy to Improve Oxygenation in Hypoxemic Respiratory Failure Secondary to COVID-19.

PURPOSE: High-flow nasal cannula (HFNO) reduces the need for invasive mechanical ventilation in COVID-19 patients with hypoxemic-respiratory failure. During HFNO entrainment of room air dilutes the delivered fractional inspiratory oxygen (FiO2), thereby preventing improvement in oxygenation. The placement of a mask over HFNO to improve oxygenation has provided conflicting results. We aimed to determine and compare the effect of placing various mask types over HFNO on oxygen saturation (SPO2). MATERIALS AND METHODS: In this prospective physiological study 40 patients with COVID-19-associated hypoxemic respiratory failure on HFNO with O2 concentration <92% were included. The effect of placing different masks over HFNO on oxygenation, respiratory rate, heart rate, blood pressure, patient comfort, and partial pressure of carbon dioxide level (pCO2) was recorded after a prespecified time interval. RESULTS: We observed a significantly higher mean SPO2 and lower mean respiratory rate on using various study masks over HFNO compared to HFNO alone. On comparing various mask types, the use of N95 masks and nonrebreather (NRB) masks with O2 showed a significant increase in O2 concentration and reduction in respiratory rate compared to surgical mask (SM) and NRB without O2. The proportion of patients who achieved SPO2 of >92% was higher with the use of N95 masks (47.5%) or NRB with O2 (45%) over HFNO compared to SM (35%) and NRB without O2 (35%). No significant change was observed in heart rate, blood pressure, and CO2 level with the use of any mask over HFNO. CONCLUSION: This study demonstrates improvement in oxygenation and reduction in respiratory rate with the use of various masks over HFNO in patients of COVID-19-related hypoxemic-respiratory-failure. Significantly greater benefit was achieved with the use of N95 or NRB with O2 compared to SM or NRB without O2.

Chronic Obstructive Pulmonary Disease and Oxygen Therapy: A Double-edged Sword.

Oxygen, like all medicines, is a drug which needs moderation. Hypoxia, as well as excess oxygen supplementation, can be harmful in a patient with chronic obstructive pulmonary disease (COPD). Both the European and the British guidelines recommend a target oxygen saturation of 88-92% in patients with COPD. Hypoxia can result in symptoms, such as restlessness, anxiety, agitation, and headache, while excess oxygen can lead to altered sensorium due to the retention of carbon dioxide (CO2) in patients with COPD. We often come across patients who come with breathlessness and have hypoxia, and the knee-jerk reaction is to start the patient on oxygen support to maintain an oxygen saturation of >95%, and this may result in hypercapnia and type II respiratory failure. Here, we present a descriptive review of the proper application of oxygen therapy in a patient presenting with acute exacerbation of COPD, the rationale behind the target oxygen saturations, and the mechanisms of type II respiratory failure due to hyperoxygenation.

Automated oxygen titration with non-invasive ventilation in hypoxaemic adults with cardiorespiratory disease: a randomised cross-over trial.

BACKGROUND: Closed-loop oxygen control systems automatically adjust the fraction of inspired oxygen (FiO2) to maintain oxygen saturation (SpO2) within a predetermined target range. Their performance with low and high-flow oxygen therapies, but not with non-invasive ventilation, has been established. We compared the effect of automated oxygen on achieving and maintaining a target SpO2 range with nasal high flow (NHF), bilevel positive airway pressure (bilevel) and continuous positive airway pressure (CPAP), in stable hypoxaemic patients with chronic cardiorespiratory disease. METHODS: In this open-label, three-way cross-over trial, participants with resting hypoxaemia (n=12) received each of NHF, bilevel and CPAP treatments, in random order, with automated oxygen titrated for 10 min, followed by 36 min of standardised manual oxygen adjustments. The primary outcome was the time taken to reach target SpO2 range (92%-96%). Secondary outcomes included time spent within target range and physiological responses to automated and manual oxygen adjustments. RESULTS: Two participants were randomised to each of six possible treatment orders. During automated oxygen control (n=12), the mean (±SD) time to reach target range was 114.8 (±87.9), 56.6 (±47.7) and 67.3 (±61) seconds for NHF, bilevel and CPAP, respectively, mean difference 58.3 (95% CI 25.0 to 91.5; p=0.002) and 47.5 (95% CI 14.3 to 80.7; p=0.007) seconds for bilevel and CPAP versus NHF, respectively. Proportions of time spent within target range were 68.5% (±16.3), 65.6% (±28.7) and 74.7% (±22.6) for NHF, bilevel and CPAP, respectively.Manually increasing, then decreasing, the FiO2 resulted in similar increases and then decreases in SpO2 and transcutaneous carbon dioxide (PtCO2) with NHF, bilevel and CPAP. CONCLUSION: The target SpO2 range was achieved more quickly when automated oxygen control was initiated with bilevel and CPAP compared with NHF while time spent within the range across the three therapies was similar. Manually changing the FiO2 had similar effects on SpO2 and PtCO2 across each of the three therapies. TRIAL REGISTRATION NUMBER: ACTRN12622000433707.

Altitude illnesses.

Millions of people visit high-altitude regions annually and more than 80 million live permanently above 2,500 m. Acute high-altitude exposure can trigger high-altitude illnesses (HAIs), including acute mountain sickness (AMS), high-altitude cerebral oedema (HACE) and high-altitude pulmonary oedema (HAPE). Chronic mountain sickness (CMS) can affect high-altitude resident populations worldwide. The prevalence of acute HAIs varies according to acclimatization status, rate of ascent and individual susceptibility. AMS, characterized by headache, nausea, dizziness and fatigue, is usually benign and self-limiting, and has been linked to hypoxia-induced cerebral blood volume increases, inflammation and related trigeminovascular system activation. Disruption of the blood-brain barrier leads to HACE, characterized by altered mental status and ataxia, and increased pulmonary capillary pressure, and related stress failure induces HAPE, characterized by dyspnoea, cough and exercise intolerance. Both conditions are progressive and life-threatening, requiring immediate medical intervention. Treatment includes supplemental oxygen and descent with appropriate pharmacological therapy. Preventive measures include slow ascent, pre-acclimatization and, in some instances, medications. CMS is characterized by excessive erythrocytosis and related clinical symptoms. In severe CMS, temporary or permanent relocation to low altitude is recommended. Future research should focus on more objective diagnostic tools to enable prompt treatment, improved identification of individual susceptibilities and effective acclimatization and prevention options.

Noninvasive Ventilation for Preoxygenation during Emergency Intubation.

BACKGROUND: Among critically ill adults undergoing tracheal intubation, hypoxemia increases the risk of cardiac arrest and death. The effect of preoxygenation with noninvasive ventilation, as compared with preoxygenation with an oxygen mask, on the incidence of hypoxemia during tracheal intubation is uncertain. METHODS: In a multicenter, randomized trial conducted at 24 emergency departments and intensive care units in the United States, we randomly assigned critically ill adults (age, ≥18 years) undergoing tracheal intubation to receive preoxygenation with either noninvasive ventilation or an oxygen mask. The primary outcome was hypoxemia during intubation, defined by an oxygen saturation of less than 85% during the interval between induction of anesthesia and 2 minutes after tracheal intubation. RESULTS: Among the 1301 patients enrolled, hypoxemia occurred in 57 of 624 patients (9.1%) in the noninvasive-ventilation group and in 118 of 637 patients (18.5%) in the oxygen-mask group (difference, -9.4 percentage points; 95% confidence interval [CI], -13.2 to -5.6; P<0.001). Cardiac arrest occurred in 1 patient (0.2%) in the noninvasive-ventilation group and in 7 patients (1.1%) in the oxygen-mask group (difference, -0.9 percentage points; 95% CI, -1.8 to -0.1). Aspiration occurred in 6 patients (0.9%) in the noninvasive-ventilation group and in 9 patients (1.4%) in the oxygen-mask group (difference, -0.4 percentage points; 95% CI, -1.6 to 0.7). CONCLUSIONS: Among critically ill adults undergoing tracheal intubation, preoxygenation with noninvasive ventilation resulted in a lower incidence of hypoxemia during intubation than preoxygenation with an oxygen mask. (Funded by the U.S. Department of Defense; PREOXI ClinicalTrials.gov number, NCT05267652.).

Identifying risk factors for hypoxemia during emergence from anesthesia in patients undergoing robot-assisted laparoscopic radical prostatectomy.

Robot-assisted laparoscopic radical prostatectomy (RALP) has emerged as an effective treatment for prostate cancer with obvious advantages. This study aims to identify risk factors related to hypoxemia during the emergence from anesthesia in patients undergoing RALP. A cohort of 316 patients undergoing RALP was divided into two groups: the hypoxemia group (N = 134) and the non-hypoxemia group (N = 182), based on their postoperative oxygen fraction. Comprehensive data were collected from the hospital information system, including preoperative baseline parameters, intraoperative data, and postoperative recovery profiles. Risk factors were examined using multiple logistic regression analysis. The study showed that 38.9% of patients had low preoperative partial pressure of oxygen (PaO2) levels. Several clinical parameters showed significant differences between the hypoxemia group and the non-hypoxemia group, including weight (P < 0.0001), BMI (P < 0.0001), diabetes mellitus (P = 0.044), history of emphysema and pulmonary alveoli (P < 0.0001), low preoperative PaO2 (P < 0.0001), preoperative white blood cell count (P = 0.012), preoperative albumin (P = 0.048), intraoperative bleeding (P = 0.043), intraoperative CO2 accumulation (P = 0.001), duration of surgery (P = 0.046), postoperative hemoglobin level (P = 0.002), postoperative hypoxemia (P = 0.002), and early postoperative fever (P = 0.006). Multiple logistic regression analysis revealed BMI (adjusted odds ratio = 0.696, 95% confidence interval 0.612-0.719), low preoperative PaO2 (adjusted odds ratio = 9.119, 95% confidence interval 4.834-17.203), and history of emphysema and pulmonary alveoli (adjusted odds ratio = 2.804, 95% confidence interval 1.432-5.491) as independent factors significantly associated with hypoxemia on emergence from anesthesia in patients undergoing RALP. Our results demonstrate that BMI, lower preoperative PaO2, and a history of emphysema and pulmonary alveolar disease are independent risk factors associated with hypoxemia on emergence from anesthesia in patients undergoing RALP. These findings provide a theoretical framework for surgeons and anesthesiologists to facilitate strategies to mitigate postoperative hypoxemia in this unique patient population.

High-flow nasal cannula oxygen reduced hypoxemia in patients undergoing gastroscopy under general anesthesia at ultra-high altitude: a randomized controlled trial.

BACKGROUND: Hypoxemia can occur in people at ultra-high altitude (above 3500 m) even at rest, and patients undergoing gastroscopy under general anesthesia have higher risk of hypoxemia. Supplementary oxygen via standard nasal cannula (SNC) is the standard of care for most patients who undergo gastroscopy under general anesthesia, which provides oxygen flow up to 15 L/min. High-flow nasal cannula (HFNC) could deliver oxygen at a rate up to 60 L/min, which is recommended by the American Society of Anesthesiologists Practice Guidelines. We speculated that the benefit with HFNC is more prominent in high-altitude areas, and aimed to compare the incidence of hypoxemia during gastroscopy under general anesthesia at ultra-high altitude with oxygen supply via either HFNC or SNC. METHODS: The trial was registered at at Chinese Clinical Trial Registry (ChiCTR2100045513; date of registration on 18/04/2021). Adult patients undergoing gastroscopy with anesthesia (estimated duration of anesthesia at ≥ 15 min) were randomized at a 1:1 ratio to receive HFNC oxygen or SNC oxygen. The primary outcome was hypoxemia (SpO2 < 90% for any duration). Secondary outcomes included severe hypoxemia (SpO2 < 75% for any duration or SpO2 < 90% but ≥ 75% for ≥ 60 s) and hypotension, as defined by reduction of mean arterial blood pressure by ≥ 25% from the baseline. RESULTS: A total of 262 patients were enrolled: 129 in the HFNC group and 133 in the SNC group. All patients received the designated intervention. Student's t-test, Mann-Whitney U test and χ2 test were employed in the study. The rate of hypoxemia was 9.3% (12/129) in the HFNC group versus 36.8% (49/133) in the SNC group [risk ratio (95% confidence interval): 0.25(0.14-0.45); P < 0.001). The HFNC group also had lower rate of severe hypoxemia [0.0% (0/129) versus 11.3% (15/133); risk ratio (95% confidence interval): 0.03(0.00-0.55); P < 0.001, respectively]. The rate of hypotension did not differ between the 2 groups [22.5% (29/129) in HFNC group versus 21.1% (28/133) in SNC group; risk ratio (95% confidence interval): 1.07(0.67-1.69) ; P = 0.779]. CONCLUSION: HFNC oxygen reduced the incidence of hypoxemia during anesthesia in adult patients undergoing gastroscopy at ultra-high altitude.

Breath-Hold Diving Injuries - A Primer for Medical Providers.

ABSTRACT: Breath-hold divers, also known as freedivers, are at risk of specific injuries that are unique from those of surface swimmers and compressed air divers. Using peer-reviewed scientific research and expert opinion, we created a guide for medical providers managing breath-hold diving injuries in the field. Hypoxia induced by prolonged apnea and increased oxygen uptake can result in an impaired mental state that can manifest as involuntary movements or full loss of consciousness. Negative pressure barotrauma secondary to airspace collapse can lead to edema and/or hemorrhage. Positive pressure barotrauma secondary to overexpansion of airspaces can result in gas embolism or air entry into tissues and organs. Inert gas loading into tissues from prolonged deep dives or repetitive shallow dives with short surface intervals can lead to decompression sickness. Inert gas narcosis at depth is commonly described as an altered state similar to that experienced by compressed air divers. Asymptomatic cardiac arrhythmias are common during apnea, normally reversing shortly after normal ventilation resumes. The methods of glossopharyngeal breathing (insufflation and exsufflation) can add to the risk of pulmonary overinflation barotrauma or loss of consciousness from decreased cardiac preload. This guide also includes information for medical providers who are tasked with providing medical support at an organized breath-hold diving event with a list of suggested equipment to facilitate diagnosis and treatment outside of the hospital setting.

Hypoxaemia risk in pediatric flexible bronchoscopy for foreign body removal: a retrospective study.

BACKGROUND: Hypoxemia represents the most prevalent adverse event during flexible bronchoscopy procedures aimed at foreign body retrieval in pediatric patients; if not expeditiously managed, it carries the potential for cardiac or respiratory arrest. The specific risk factors contributing to the occurrence of hypoxemia during foreign body FB removal via bronchoscopy have yet to be definitively established. METHODS: This retrospective study included a cohort of 266 pediatric subjects from January 1, 2015, to December 31, 2022, who underwent flexible bronchoscopy for the purpose of FB extraction. In this cohort, the supraglottic airway was used to connect the anesthesia apparatus during the removal procedure. RESULTS: In total, 45 of the pediatric patients (16.9%) experienced episodes of hypoxemia during the FB removal procedure. Multivariate analysis revealed that the following factors were significantly associated with the occurrence of hypoxemia: an operation time exceeding 60 min (odds ratio [OR] 8.55; 95% confidence interval [CI] 3.82-19.13), a maximum diameter exceeding 7 mm (OR 5.03; 95% CI, 2.24-11.29), and the presence of radiological evidence indicating pneumonia (OR 2.69; 95% CI, 1.27-5.69). CONCLUSION: During flexible bronchoscopy procedures aimed at FB removal in pediatric patients, there is an increased susceptibility to hypoxemia. Factors including extended operation duration, larger FB dimensions, and radiographic evidence suggestive of pneumonia significantly contribute to a heightened risk of hypoxemia.

Study on risk factors and treatment strategies of hypoxemia after acute type a aortic dissection surgery.

Acute type A aortic dissection is a life-threatening cardiovascular disease characterized by rapid onset and high mortality. Emergency surgery is the preferred and reliable treatment option. However, postoperative complications significantly impact patient prognosis. Hypoxemia, a common complication, poses challenges in clinical treatment, negatively affecting patient outcomes and increasing the risk of mortality. Therefore, it is crucial to study and comprehend the risk factors and treatment strategies for hypoxemia following acute type A aortic dissection to facilitate early intervention.

Post-pandemic acute respiratory distress syndrome: A New Global Definition with extension to lower-resource regions.

Acute respiratory distress syndrome (ARDS), first described in 1967, is characterized by acute respiratory failure causing profound hypoxemia, decreased pulmonary compliance, and bilateral CXR infiltrates. After several descriptions, the Berlin definition was adopted in 2012, which established three categories of severity according to hypoxemia (mild, moderate and severe), specified temporal aspects for diagnosis, and incorporated the use of non-invasive ventilation. The COVID-19 pandemic led to changes in ARDS management, focusing on continuous monitoring of oxygenation and on utilization of high-flow oxygen therapy and lung ultrasound. In 2021, a New Global Definition based on the Berlin definition of ARDS was proposed, which included a category for non-intubated patients, considered the use of SpO2, and established no particular requirement for oxygenation support in regions with limited resources. Although debates persist, the continuous evolution seeks to adapt to clinical and epidemiological needs, and to the search of personalized treatments.

Effects of sleep-disordered breathing on serum lipid levels in children:a case control study.

BACKGROUND: Sleep-disordered breathing (SDB) during childhood is common and includes a range of breathing abnormalities that range from primary snoring (PS) to obstructive sleep apnea syndrome (OSAS).Studies have shown that not only OSAS, but also PS, which is originally considered harmless, could cause cardiovascular, cognitive, behavioral, and psychosocial problems. Many researches are focused on the relation of OSA and serum lipid levels. However, little studies are focused on PS and serum lipid levels in children.We evaluated whether serum lipid (total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C),low-density lipoprotein cholesterol (LDL-C)) concentrations were associated with specific components of SDB, including indices of oxygen reduction index, lowest oxygen saturation, mean oxygen saturation. And we explored whether serum lipid levels were associated with different degree sleep disordered (PS and OSA group) and obese. METHODS: This was a cross-sectional study. Children who were complained by their guardians with habitual snoring and(or) mouth breathing were collected in the SDB group. Normal children without sleep problem were matched in the control group. Subjects in the SDB group underwent polysomnography. The serum lipid profiles of all the children included TC, TG, HDL-C and LDL-C concentrations were measured by appropriate enzymatic assays. RESULTS: A total of 241 with Apnea/Hypopnea Index ≥ 5 (AHI) were assigned to the OSAS group and the remaining 155 with normal AHI were assigned to the PS group. The values of TC, TG, LDL-C and LDL/HDL were significantly higher in the OSAS group than in the PS group, and the values in the PS group were significantly higher than the control group. Multiple regression analysis revealed serum TG only correlated negatively with lowest oxygen saturation. Body mass index-z score has a positive effect on TG in all the 1310 children (P = 0.031) and in SDB 396 children(P = 0.012). The level of serum TG in obese group was significantly higher than that in non-obese group. CONCLUSIONS: SDB had a very obvious effect on blood lipids, whereas PS without apnea and hypoxia. Obese only affects the aggregation of TG. TRIAL REGISTRATION: ChiCTR1900026807(2019.10.23).

A rare case of methemoglobinemia in a preterm newborn with unclear etiology.

 Cyanosis is a bluish discoloration of the tissues due to increased levels of deoxygenated hemoglobin in capillaries. It is a common finding in newborn infants that can be caused by different diseases, including pulmonary, cardiac, infectious, and hematological disorders. Methemoglobinemia is a rare cause of cyanosis, in which hemoglobin is oxidized, changing its heme iron configuration from the ferrous (Fe2 +) to the ferric (Fe3 +) state, creating methemoglobin (Met-Hb), a form that does not bind oxygen, leading to decreased oxygen delivery to the tissues and cyanosis. We report a rare case of a preterm newborn, who developed cyanosis and worsening hypoxemia on day ten of life, she was found to have elevated Met-Hb percentage in blood gas analysis that required treatment with intravenous methylene blue. Her symptoms resolved after a period of maintenance treatment with oral methylene blue and ascorbic acid, and the etiology of her disease remains unclear.