Search Results (19)

Emergent tracheal intubation in critically ill patients is a common, yet high-risk, intervention. It is frequently complicated by peri-intubation hypoxemia, hemodynamic instability, and metabolic derangements that increase the risk of arrhythmias, hypotension, cardiac arrest, and death. Because the highest-risk interval often occurs in the minutes surrounding induction, when apnea, derecruitment, and abrupt cardiopulmonary shifts converge, oxygenation failure frequently reflects a mismatch between preoxygenation strategy and the underlying physiology rather than inadequate oxygen delivery alone. This review proposes a phenotype-based approach to peri-intubation oxygenation and focuses on four high-risk phenotypes in whom standard preoxygenation strategies commonly fail: obesity, neuromuscular disease, right ventricular dysfunction or pulmonary hypertension, and post-operative respiratory failure with altered respiratory mechanics or airway anatomy. We summarize the key mechanisms that shorten safe apnea time, including reduced functional residual capacity, intrapulmonary shunt, elevated oxygen consumption, rapid derecruitment after induction, and impaired oxygenation–hemodynamics coupling. We then compare preoxygenation modalities as physiologic tools, including facemask oxygen, high-flow nasal cannula (HFNC), noninvasive ventilation (NIV), and controlled bag-mask ventilation (BMV), and integrate contemporary randomized trial evidence that informs bedside selection and combination of these approaches. Finally, we synthesize these concepts into a practical, physiology-informed framework to guide clinicians in choosing and troubleshooting preoxygenation strategies in high-risk patients undergoing emergent intubation. Full article

Background/Objectives: Preoxygenation with 100% oxygen is commonly used but poses risks such as hyperoxia and atelectasis. Using 80% oxygen may reduce these effects but shortens duration of apnoea without desaturation (DAWD). This study compared preoxygenation efficiency between 80% and 100% oxygen and evaluated changes in the Oxygen Reserve Index™ (ORi™). Methods: Patients undergoing elective laparoscopic cholecystectomy were randomized to preoxygenation with 80% or 100% oxygen. Adequate preoxygenation was defined as a ≤10% difference between fraction of inspired oxygen and end-tidal oxygen (EtCO₂). The primary outcome was DAWD, the interval from apnoea onset to peripheral oxygen saturation (SpO₂) of 93%. Secondary outcomes included time to adequate preoxygenation and additional warning time from ORi™ zero to SpO₂ 97%. Results: Thirty patients were randomised to 80% (n = 15) or 100% oxygen (n = 15) oxygen groups. One patient in the 100% group was excluded due to spontaneous breathing before SpO₂ 93%, leaving 29 for DAWD analysis. DAWD was 345 ± 136 s (80%) and 430 ± 163 s (100%) with a mean difference of 86 s (p = 0.135). No significant differences were observed in tie to adequate preoxygenation or additional warning time. Conclusions: Preoxygenation with 80% oxygen resulted in a numerically shorter DAWD compared with 100% oxygen, without a significant difference in ORi™. These findings may suggest the potential feasibility of using 80% oxygen for preoxygenation. However, given the limited sample size and uncertain clinical relevance, further large-scale studies are warranted to clarify the safety and clinical implications of lower oxygen concentration during anaesthesia induction. Full article

Tracheal intubation is a frequent and high-risk procedure in the intensive care unit (ICU). Unlike elective intubation in the operating room, ICU intubation is often performed under emergent conditions in physiologically unstable patients, leading to increased technical difficulty and higher complication rates. Among these, hypoxemia is particularly frequent and represents a major determinant of morbidity and mortality. Optimizing preoxygenation is therefore a cornerstone of safe airway management in critically ill patients. The aim of this review is to explore the advantages and limitations of each preoxygenation strategy and to provide clinicians with clear, practical guidance to optimize airway management in the ICU. Preoxygenation aims to increase oxygen reserves in order to prolong the duration of safe apnea. Conventional methods include high-flow oxygen delivery through a tightly fitted face mask, though efficacy depends on minimizing leaks. More advanced strategies include non-invasive ventilation (NIV), which improves both alveolar oxygen fraction and lung volume, and high-flow nasal cannula (HFNC), which additionally allows apneic oxygenation during intubation. Randomized controlled trials, including the recent PREOXY study, demonstrate the superiority of NIV over facemask preoxygenation in reducing peri-intubation desaturation, particularly in hypoxemic patients. HFNC is valuable when NIV is contraindicated, while combined approaches (NIV plus HFNC) may further enhance efficacy. Beyond technique, structured protocols and team organization are crucial to reduce complications. In conclusion, preoxygenation is an essential, patient-specific intervention that mitigates the risks of ICU intubation. Familiarity with available methods enables clinicians to tailor strategies, optimize oxygenation, and improve patient safety during this high-risk procedure. Full article

Pre-oxygenation is the key step prior to endotracheal intubation, particularly in a critically ill patient, to prevent life-threatening peri-procedural hypoxemia. This narrative review explores the emerging interest of Non-Invasive Positive Pressure Ventilation (NIPPV) as a pre-oxygenation modality in the intensive care unit (ICU) context. We reviewed data from randomized controlled trials (RCTs) and observational studies published from 2000 to 2024 that compare NIPPV to conventional oxygen therapy and High Flow Nasal Cannula Oxygen (HFNCO). The pathophysiological mechanisms for the successful use of NIPPV, including alveolar recruitment, the decrease of shunting, and the maintenance of functional residual capacity, were reviewed in depth. Existing studies show that NIPPV significantly prolongs the apnea time, reduces the rate of peri-intubation severe hypoxaemia in selected patients and is especially effective for patients with acute hypoxaemic respiratory failure. Nevertheless, appropriate patient selection is still crucial because some diseases can contraindicate or even be harmful with NIPPV. We further discussed the practical aspects of how to use this ventilatory support (the best ventilator settings, which interface, and when to apply it). We lastly discuss unanswered questions and offer suggestions and opportunities for future exploration in guiding the role of NIPPV use in the pre-oxygenation of the critically ill patient requiring emergent airway management. Full article

Background: Airway management in patients with obstructive sleep apnea (OSA) presents unique challenges for anesthesiologists and other airway practitioners. This comprehensive review examines current evidence and clinical practices for managing difficult airways in this high-risk population. OSA is characterized by specific anatomical and physiological alterations that increase both the likelihood of encountering difficult intubation and the risk of rapid desaturation during airway manipulation. Methods: Preoperative assessment of OSA patients requires integration of traditional difficult airway evaluation with OSA-specific considerations, including severity indices, oxygen desaturation patterns, and continuous positive airway pressure dependency. Conventional direct laryngoscopy often proves inadequate in these patients, prompting the development and refinement of alternative approaches. Videolaryngoscopy has emerged as a particularly valuable technique in OSA patients, offering improved glottic visualization while maintaining physiologic positioning. Flexible endoscopic techniques, particularly awake flexible bronchoscopic intubation, remain essential for high-risk scenarios, though they require considerable expertise. Results: Recent technological innovations have produced hybrid devices combining multiple modalities to address the specific challenges presented by OSA patients. Adjunctive tools and techniques, including specialized introducers, exchange catheters, and high-flow nasal oxygen, play critical roles in extending safe apnea time and facilitating successful intubation. Professional society guidelines now incorporate OSA-specific recommendations, emphasizing thorough preparation, appropriate device selection, and comprehensive monitoring. Conclusions: Effective management ultimately requires not only appropriate technology but also systematic preparation, strategic device selection, and meticulous execution. As OSA prevalence continues to rise globally, optimizing airway management approaches for this challenging population remains a critical priority for patient safety. Full article

Background: The management of difficult airways is one of the most critical and challenging aspects of emergency and ICU care. Despite technological advances, unanticipated airway difficulty can result in serious complications, including hypoxia, brain injury, and death. This comprehensive narrative review aims to consolidate current algorithms and evidence-based strategies to guide clinicians in the assessment and management of difficult airways. Methods: A comprehensive literature review was conducted using PubMed, Embase, and Google Scholar to identify relevant studies, clinical guidelines, and expert consensus documents related to difficult airway management. The focus was placed on both pre-intubation assessment tools and intervention strategies used in various clinical contexts. Results: Airway difficulty is best anticipated through a combination of history, physical examination, and validated tools such as the Mallampati score. Several algorithms, including those from the American Society of Anesthesiologists (ASA) and the Difficult Airway Society (DAS), provide structured approaches that emphasize preoxygenation, preparedness for failed intubation, and the use of adjuncts such as video laryngoscopy, supraglottic airway devices, and awake intubation techniques. Crisis algorithms such as the Vortex approach help simplify decision-making during emergencies. It is important to have adjuncts available in cases of anticipated difficult airways, such as fiberoptic intubation, while surgical airway access is an important component of a stepwise airway management algorithm when critical scenarios are encountered. Conclusions: Effective difficult airway management requires anticipation, a structured plan, familiarity with advanced airway tools, and adherence to validated algorithms. Training in crisis resource management and multidisciplinary rehearsal of airway scenarios are essential to improving outcomes. Full article

Background/Objectives: Rapid sequence induction (RSI) for the prevention of aspiration is a frequent clinical situation during anesthesia. The lack of international guidelines on this topic may lead to differences in practices. The aim of this survey is to identify the clinical practices in RSI among practitioners at an international level. Methods: International declarative survey across the ESAIC network. Results: A total of 491 respondents in 61 countries, 74% of them were seniors and 42% with over 20 years of experience. Most of the practitioners (87%) performed preoxygenation under a high flow of oxygen (>10 L/min) with no PEEP and no pressure support and 69% use opioids in most cases of RSI. The Sellick maneuver was used by 42% of respondents. RSI was used in most situations at high risk of aspiration (bowel obstruction, trauma within 6 h after the last meal, caesarian section). RSI was used in 53% of cases of appendicectomy in the absence of vomiting. Conversely, 29% did not use RSI in cases of symptomatic esophageal reflux. A total of 11% encountered at least one episode of grade IV anaphylaxis to succinylcholine or rocuronium and 24% aspiration pneumonia. Conclusions: Our results support the need for international guidelines on RSI to limit differences between practitioners and countries. Full article

Background and Objectives: Oxygen is essential for all living organisms and plays a critical role in anesthesia and intensive care practices. However, the notion that unlimited oxygen therapy is harmless is a misconception. Our study investigates the acute effects of different preoxygenation methods on hemodynamic parameters and neurodegenerative biomarkers in patients undergoing laparoscopic cholecystectomy surgery. Materials and Methods: This prospective, randomized, controlled study included 52 patients undergoing elective laparoscopic cholecystectomy under general anesthesia. Patients were divided into two groups: Group I received standard preoxygenation (100% FiO₂ for 3 min), while Group II underwent rapid preoxygenation (eight deep breaths over 30 s to 1 min). Hemodynamic parameters (SAP, DAP, MAP, and SpO₂) and neurodegenerative biomarkers (pTau, S100B, NSE, NfL, GFAP) were measured after preoxygenation, after intubation, and at the end of surgery. Results: Group I exhibited a significant increase in levels of pTau, S100B, NSE, and GFAP, indicating higher neuronal and glial cell stress compared to Group II (p < 0.001). No significant increase in NfL levels was observed in either group. Hemodynamic parameters (HR, SAP, DAP, MAP) were significantly higher during and after preoxygenation in Group I, suggesting an increased stress response. Group II showed lower levels of acute neurotoxicity and oxidative stress. Conclusions: Our findings indicate that preoxygenation with 100% FiO₂ induces stress in neuronal cells, axons, and glial cells, leading to an increase in neurodegenerative biomarkers. Optimizing preoxygenation strategies is crucial to reduce oxidative stress and improve neurological outcomes for surgical patients. Full article

We aim to provide reference values for military aircrews participating in hypoxia awareness training (HAT). We describe several parameters with potential biomedical interest based on selected segments and slopes of the changes in oxygen saturation (SatO₂) during a standard HAT. A retrospective analysis of 2298 records of the SatO₂ curve was performed, including 1526 military men aged 30.48 ± 6.47 years during HAT in a hypobaric chamber. HAT consisted of pre-oxygenation at 100% and an ascent to 7620 m, followed by O₂ disconnection starting the phase of descent of SatO₂ until reaching the time of useful consciousness (TUC), and finally reconnection to 100% O₂ in the recovery phase. Using an ad hoc computational procedure, the time taken to reach several defined critical values was computed. These key parameters were the time until desaturation of 97% and 90% (hypoxia) after oxygen mask disconnection (D97/D90) and reconnection (R97/R90) phases, the time of desaturation (TUC-D97) and hypoxia (TUC-D90) during disconnection, the total time in desaturation (L97) or hypoxia (L90), and the slopes of SatO₂ drop (SDSAT97 and SDSAT90) and recovery (SRSAT97). The mean of the quartiles according to TUC were compared by ANOVA. The correlations between the different parameters were studied using Pearson’s test and the effect size was estimated with ω². Potentially useful parameters for the HAT study were those with statistical significance (p < 0.05) and a large effect size. D97, D90, R97, and R90 showed significant differences with small effect sizes, while TUC-D97, TUC-D90, L97, L90, and SDSAT97 showed significant differences and large effect sizes. SDSAT97 correlated with TUC (R = 0.79), TUC-D97 (R = 0.81), and TUC-D90 (R = 0.81). In conclusion, several parameters of the SatO₂ curve are useful for the study and monitoring of HAT. The SDSAT97 measured during the test can estimate the TUC and thus contribute to taking measures to characterize and protect the aircrew members. Full article

Extracorporeal membrane oxygenation (ECMO) is an important rescue therapy method for the treatment of severe hypoxic lung injury. In some cases, oxygen saturation and oxygen partial pressure in the arterial blood are low despite ECMO therapy. There are case reports in which patients with such instances of refractory hypoxemia received a second membrane lung, either in series or in parallel, to overcome the hypoxemia. It remains unclear whether the parallel or serial connection is more effective. Therefore, we used an improved version of our full-flow ECMO mock circuit to test this. The measurements were performed under conditions in which the membrane lungs were unable to completely oxygenate the blood. As a result, only the photometric pre- and post-oxygenator saturations, blood flow and hemoglobin concentration were required for the calculation of oxygen transfer rates. The results showed that for a pre-oxygenator saturation of 45% and a total blood flow of 10 L/min, the serial connection of two identical 5 L rated oxygenators is 17% more effective in terms of oxygen transfer than the parallel connection. Although the idea of using a second membrane lung if refractory hypoxia occurs is intriguing from a physiological point of view, due to the invasiveness of the solution, further investigations are needed before this should be used in a wider clinical setting. Full article

Background: Tracheal intubation in critical care is a high-risk procedure requiring significant expertise and airway strategy modification. We hypothesise that awake tracheal intubation is associated with a lower incidence of severe adverse events compared to standard tracheal intubation in critical care patients. Methods: Records were acquired for all tracheal intubations performed from 2020 to 2022 for critical care patients at a tertiary hospital. Each awake tracheal intubation case, using a videolaryngoscope with a hyperangulated blade (McGrath^® MAC X-Blade), was propensity matched with two controls (1:2 ratio; standard intubation videolaryngoscopy (VL) and direct laryngoscopy (DL) undergoing general anaesthesia). The primary endpoint was the incidence of adverse events, defined as a mean arterial pressure of <55 mmHg (hypotension), SpO₂ < 80% (desaturation) after sufficient preoxygenation, or peri-interventional cardiac arrest. Results: Of the 135 tracheal intubations included for analysis, 45 involved the use of an awake tracheal intubation. At least one adverse event occurred after tracheal intubation in 36/135 (27%) of patients, including awake 1/45 (2.2%; 1/1 hypotension), VL 10/45 (22%; 6/10 hypotension and 4/10 desaturation), and DL 25/45 (47%; 10/25 hypotension, 12/25 desaturation, and 3/25 cardiac arrest; p < 0.0001). Conclusions: In this retrospective observational study of intubation practices in critical care patients, awake tracheal intubation was associated with a lower incidence of severe adverse events than anaesthetised tracheal intubation. Full article

Hydromedusan photoproteins responsible for the bioluminescence of a variety of marine jellyfish and hydroids are a unique biochemical system recognized as a stable enzyme-substrate complex consisting of apoprotein and preoxygenated coelenterazine, which is tightly bound in the protein inner cavity. The binding of calcium ions to the photoprotein molecule is only required to initiate the light emission reaction. Although numerous experimental and theoretical studies on the bioluminescence of these photoproteins were performed, many features of their functioning are yet unclear. In particular, which ionic state of dioxetanone intermediate decomposes to yield a coelenteramide in an excited state and the role of the water molecule residing in a proximity to the N1 atom of 2-hydroperoxycoelenterazine in the bioluminescence reaction are still under discussion. With the aim to elucidate the function of this water molecule as well as to pinpoint the amino acid residues presumably involved in the protonation of the primarily formed dioxetanone anion, we constructed a set of single and double obelin and aequorin mutants with substitutions of His, Trp, Tyr, and Ser to residues with different properties of side chains and investigated their bioluminescence properties (specific activity, bioluminescence spectra, stopped-flow kinetics, and fluorescence spectra of Ca²⁺-discharged photoproteins). Moreover, we determined the spatial structure of the obelin mutant with a substitution of His64, the key residue of the presumable proton transfer, to Phe. On the ground of the bioluminescence properties of the obelin and aequorin mutants as well as the spatial structures of the obelin mutants with the replacements of His64 and Tyr138, the conclusion was made that, in fact, His residue of the Tyr-His-Trp triad and the water molecule perform the “catalytic function” by transferring the proton from solvent to the dioxetanone anion to generate its neutral ionic state in complex with water, as only the decomposition of this form of dioxetanone can provide the highest light output in the light-emitting reaction of the hydromedusan photoproteins. Full article

Background: In a cannot-ventilate-cannot-intubate situation, careful preoxygenation with high FiO₂ allowing subsequent apneic oxygenation can be life-saving. The best position for an oxygen supply line within the human airway at which oxygen insufflation is more effective than standard preoxygenation with a face mask is unknown. Methods: In this experimental study, we compared the effectiveness of preoxygenation by placing an oxygen cannula at the nose entrance, through the nose at the soft palatine, or at the base of the tongue; as a control we used ambient air. We connected a fully preoxygenated test lung on one side to an oximeter with a flow rate of 200 mL/min simulating the oxygen consumption of a normal adult on the other side of the trachea of an anatomically correctly shaped airway manikin over a 20 min observation period five times for each cannula placement in a random order. Results: The oxygen percentage in the test lung dropped from 100% in all groups to 53 ± 1% in the ambient air control group, to 87 ± 2% in the nasal cannula group, and to 96 ± 2% in the soft palatine group; it remained at 99 ± 1% in the base of the tongue group (p = 0.003 for the soft palatine vs. base of the tongue and p < 0.001 for all other groups). Conclusions: When simulating apneic oxygenation in a preoxygenated manikin, oxygen insufflation at the base of the tongue kept the oxygen percentage at baseline values of 99%, demonstrating a complete block of ambient air flowing into the airway of the manikin. Oxygen insufflation at the soft palatine or insufflation via a nasal cannula were less effective regarding this effect. Full article

(1) Background: Rapid sequence induction (RSI) is carried out by anaesthetists to secure the airway promptly in patients who are at risk of aspirating gastric content during induction of anaesthesia. RSI requires variation in the paediatric population. We conducted a survey to investigate current practice of paediatric RSI by anaesthetists. (2) Methods: A descriptive, contextual, cross-sectional research design was followed. The study population consisted of all anaesthetists working in the Department of Anaesthesia at the University of the Witwatersrand. Data was collected in the form of a self-administered questionnaire. (3) Results: Of 138 questionnaires that were distributed, 126 were completed. Clinical indication for RSI was predominantly for appendicitis with peritonitis (115/124; 92.7%). Preoxygenation was performed by 95.1% of anaesthetists for children, 87% for infants and 89.4% for neonates. Cricoid pressure was used significantly more in children (56%) than in infants (20.8%) and neonates (10.3%) (p < 0.001). Rocuronium was the paralytic agent of choice in children (42.7%) and infants (38.2%), while cisatracurium was used most frequently in neonates (37.4%). Suxamethonium was used least in neonates. Cuffed ETTs were used most frequently for children (99.2%) and least for neonates (49.6%). Eighty-five percent of anaesthetists omitted cricoid pressure during RSI for pyloromyotomy, for which a controlled RSI was performed more by consultants and senior registrars (p < 0.01). A classic RSI was performed by 53.6% of anaesthetists for laparotomy for small bowel obstruction. Consultants and PMOs were more likely to intubate a child for forearm MUA who was starved for 6 h and received opioids (p < 0.05). Controlled RSI with cisatracurium was the technique of choice for Tenkhoff insertion in a child with renal failure. (4) Conclusions: RSI practice for paediatric patients varied widely among anaesthetists. This may be attributed to a combination of anaesthetic experience, training in paediatric anaesthesia, and patient specific factors, along with the individualised clinical scenario’s aspiration risk. A controlled RSI technique appears to be implemented more frequently by anaesthetists with increased experience. Full article

Airway management during the COVID-19 pandemic has been one of the most challenging aspects of care that anesthesiologists and intensivists face. This study was conducted to evaluate the management of tracheal intubation in patients with suspected or confirmed COVID-19 infection. This is a cross-sectional and international multicenter study based on a 37-item questionnaire. The survey was available to physicians who had performed intubations and tracheostomies in patients with suspected or confirmed COVID-19 and had provided informed consent to participate. The primary outcome is the preference to use a specific device for tracheal intubation. Secondary outcomes are clinical practice variables, use of video laryngoscopes, difficult airway management, and safety features to prevent cross-infection. This study included 2411 physicians who performed an average of 11.90 and 20.67 tracheal intubations in patients diagnosed or suspected of having COVID-19 disease, respectively. Physicians were mainly from the specialties of Anesthesiology (61.2%) and Intensive Care (7.4%). COVID-19 infection diagnosed by positive PCR or serology in physicians participating in intubation in this study was 15.1%. Respondents considered preoxygenation for more than three minutes very useful (75.7%). The preferred device for tracheal intubation was the video laryngoscope (64.8%). However, the direct laryngoscope (57.9%) was the most commonly used, followed by the video laryngoscope (37.5%). The preferred device to facilitate intubation was the Eschmann guide (34.2%). Percutaneous tracheostomy was the preferred technique (39.5%) over the open tracheostomy (22%). The predicted or unpredicted difficult airway management in these patients was preferably performed with a video laryngoscope (61.7% or 63.7, respectively). Intubation was mostly performed by two or more expert airway physicians (61.6%). The use of personal protective equipment increased the practitioners’ discomfort during intubation maneuvers. The video laryngoscope is the preferred device for intubating patients with COVID-19, combined with the Eschmann guide, flexible stylet within the endotracheal tube, or Frova guide to facilitate intubation. The sub-analysis of the two groups of physicians by the level of intubation experience showed a higher use of the video laryngoscope (63.4%) in the experts group and no significant differences between the two groups in terms of cross-infection rates in physicians, in their preference for the use of the video laryngoscope or in the number of intubations performed in confirmed or suspected COVID-19 patients. Full article