Inhalation gastrique : épidémiologie et facteurs de risque

Gastric Volume and Antral Area in the Fasting State: A Meta-analysis of Individual Patient Data

BACKGROUND

Pulmonary aspiration of gastric content is a serious anesthetic complication. Gastric point-of-care ultrasound can determine the type and volume of gastric content when clinical information is equivocal. However, a cutoff value of either antral cross-sectional area or volume that may be considered as the upper limit of normal in fasting subjects is still controversial. The aim of this study is to characterize the distribution of baseline antral area and volume in fasting adult subjects and to identify an upper limit (95th percentile) of these distributions.

METHODS

The authors conducted a meta-analysis of individual participant data of primary studies from an academic research network of investigators collaborating in gastric ultrasound. Studies between January 2009 and December 2020 were included.

RESULTS

Twelve primary studies met inclusion criteria and were included in the analysis with a sample size of 1,203 subjects. The 95th percentile of area values (measured in the right lateral decubitus) was 9.9 cm2 (95% CI, 9.4 to 10.4), and of volume, 2.3 ml/kg (95% CI, 2.3 to 2.4). In addition, an antrum grade 0 or 1 indicates a 98% probability of an antral area below the 95th percentile.

CONCLUSIONS

An area of 10 cm2 measured in the right lateral decubitus could be a simple, data-driven upper limit of antral area that could serve as a surrogate of upper limit of normal gastric volume values in fasting adults. These results are limited by the highly selected sampling of the studies included.

EDITOR’S PERSPECTIVE

Pre-operative gastric ultrasound in patients at risk of pulmonary aspiration: a prospective observational cohort study

Point-of-care gastric sonography offers an objective approach to assessing individual pulmonary aspiration risk before induction of general anaesthesia. We aimed to evaluate the potential impact of routine pre-operative gastric ultrasound on peri-operative management in a cohort of adult patients undergoing elective or emergency surgery at a single centre. According to pre-operative gastric ultrasound results, patients were classified as low risk (empty, gastric fluid volume ≤ 1.5 ml.kg-1 body weight) or high risk (solid, mixed or gastric fluid volume > 1.5 ml.kg-1 body weight) of aspiration. After sonography, examiners were asked to indicate changes in aspiration risk management (none; more conservative; more liberal) to their pre-defined anaesthetic plan and to adapt it if patient safety was at risk. We included 2003 patients, 1246 (62%) of which underwent elective and 757 (38%) emergency surgery. Among patients who underwent elective surgery, 1046/1246 (84%) had a low-risk and 178/1246 (14%) a high-risk stomach, with this being 587/757 (78%) vs. 158/757 (21%) among patients undergoing emergency surgery, respectively. Routine pre-operative gastric sonography enabled changes in anaesthetic management in 379/2003 (19%) of patients, with these being a more liberal approach in 303/2003 (15%). In patients undergoing elective surgery, pre-operative gastric sonography would have allowed a more liberal approach in 170/1246 (14%) and made a more conservative approach indicated in 52/1246 (4%), whereas in patients undergoing emergency surgery, 133/757 (18%) would have been managed more liberally and 24/757 (3%) more conservatively. We showed that pre-operative gastric ultrasound helps to identify high- and low-risk situations in patients at risk of aspiration and adds useful information to peri-operative management. Our data suggest that routine use of pre-operative gastric ultrasound may improve individualised care and potentially impact patient safety.

Ultrasonographic Assessment of Gastric Volume in Fasted Patients Undergoing Gastrointestinal Endoscopy Under Sedation

Purpose

In this prospective observational study, an ultrasonographic measurement of antral cross-sectional area (ACSA) was conducted to evaluate the gastric content and volume as well as to identify high-risk stomach in non-pregnant adult surgical patients adhering to preanesthetic fasting guidelines.

Patients and Methods

Fasted patients undergoing gastrointestinal endoscopy under sedation were included. Ultrasonographic measurements of ACSA were conducted in both semi-recumbent and right lateral decubitus positions before endoscopic procedures. Gastroscopy was employed to guide the measurement of suctioned gastric volume (GV). Ultrasonography was performed to assess gastric contents and identify patients with high-risk stomach. The relationship between ACSA and suctioned GV was also evaluated.

Results

ACSA was evaluated in 736 out of 782 patients. A significant positive correlation was discovered between ACSA in the right lateral decubitus position and suctioned GV, which was more reliable than in the semi-recumbent position. To analyze high-risk stomach with a GV > 100 mL, the cutoff value of ACSA in the right lateral decubitus was found to be 7.5 cm2, with the AUC, sensitivity and specificity of 0.80 (95% CI, 0.76-0.82; P<0.001), 82.4% and 67.3%, respectively. A novel mathematical model based on ACSA to estimate GV in non-pregnant fasted adults was presented.

Conclusion

Ultrasonographic measurement of ACSA can assist anesthesiologists in estimating the risk of pulmonary aspiration of gastric contents during general anesthesia and sedation.

Prospective audit on fasting status of elective ambulatory surgery patients, correlated to gastric ultrasound

INTRODUCTION

Recent guidelines advocate a preoperative fasting interval of 6 h for solid food, 4 h for breast milk and 2 h for clear fluids. Long nil per mouth intervals give rise to complications and discomfort in the perioperative period. Gastric ultrasound is easily accessible and generates reliable information about gastric content.

PATIENTS AND METHODS

One hundred patients were offered a questionnaire regarding preoperative fasting. Important outcome measures were hour of last meal, last clear fluids intake, the source of preoperative information. Gastric ultrasound was performed in prone position and lateral decubitus.

RESULTS

The mean duration of fasting for solid food was 13h29 and 9h51 for clear fluids. 48% of patients were well aware of the correct fasting guidelines. The most frequent source of information was the preoperative phone call. Gastric ultrasound only found insignificant amounts of gastric content.

DISCUSSION

Too few patients are aware of the correct guidelines or fear complications and therefore adhere to the nil per mouth from midnight as most conservative measure. A phone call informing patients about the hour of surgery and allowing clear fluid intake until 2 h before surgery, is still not convincing enough. Some health care providers advise their patients the nil per mouth from midnight rule, due to risk of interfering with the operating room schedule.

CONCLUSION

It is still difficult to implement liberal intake of clear fluids according to current guidelines. Ambulatory surgery patients have long fasting intervals with decrease of subjective well-being and increased incidence of hunger and thirst.

Effect of Remifentanil vs Neuromuscular Blockers During Rapid Sequence Intubation on Successful Intubation Without Major Complications Among Patients at Risk of Aspiration: A Randomized Clinical Trial

IMPORTANCE

It is uncertain whether a rapid-onset opioid is noninferior to a rapid-onset neuromuscular blocker during rapid sequence intubation when used in conjunction with a hypnotic agent.

OBJECTIVE

To determine whether remifentanil is noninferior to rapid-onset neuromuscular blockers for rapid sequence intubation.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, randomized, open-label, noninferiority trial among 1150 adults at risk of aspiration (fasting for <6 hours, bowel occlusion, recent trauma, or severe gastroesophageal reflux) who underwent tracheal intubation in the operating room at 15 hospitals in France from October 2019 to April 2021. Follow-up was completed on May 15, 2021.

INTERVENTIONS

Patients were randomized to receive neuromuscular blockers (1 mg/kg of succinylcholine or rocuronium; n = 575) or remifentanil (3 to 4 μg/kg; n = 575) immediately after injection of a hypnotic.

MAIN OUTCOMES AND MEASURES

The primary outcome was assessed in all randomized patients (as-randomized population) and in all eligible patients who received assigned treatment (per-protocol population). The primary outcome was successful tracheal intubation on the first attempt without major complications, defined as lung aspiration of digestive content, oxygen desaturation, major hemodynamic instability, sustained arrhythmia, cardiac arrest, and severe anaphylactic reaction. The prespecified noninferiority margin was 7.0%.

RESULTS

Among 1150 randomized patients (mean age, 50.7 [SD, 17.4] years; 573 [50%] women), 1130 (98.3%) completed the trial. In the as-randomized population, tracheal intubation on the first attempt without major complications occurred in 374 of 575 patients (66.1%) in the remifentanil group and 408 of 575 (71.6%) in the neuromuscular blocker group (between-group difference adjusted for randomization strata and center, -6.1%; 95% CI, -11.6% to -0.5%; P = .37 for noninferiority), demonstrating inferiority. In the per-protocol population, 374 of 565 patients (66.2%) in the remifentanil group and 403 of 565 (71.3%) in the neuromuscular blocker group had successful intubation without major complications (adjusted difference, -5.7%; 2-sided 95% CI, -11.3% to -0.1%; P = .32 for noninferiority). An adverse event of hemodynamic instability was recorded in 19 of 575 patients (3.3%) with remifentanil and 3 of 575 (0.5%) with neuromuscular blockers (adjusted difference, 2.8%; 95% CI, 1.2%-4.4%).

CONCLUSIONS AND RELEVANCE

Among adults at risk of aspiration during rapid sequence intubation in the operating room, remifentanil, compared with neuromuscular blockers, did not meet the criterion for noninferiority with regard to successful intubation on first attempt without major complications. Although remifentanil was statistically inferior to neuromuscular blockers, the wide confidence interval around the effect estimate remains compatible with noninferiority and limits conclusions about the clinical relevance of the difference.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03960801.

A way forward in pulmonary aspiration incidence reduction: ultrasound, mathematics, and worldwide data collection

Aspiration of gastric contents during induction of general anesthesia remains a significant cause of mortality and morbidity in anesthesia. Recent data show that pulmonary aspiration still accounts for many cases with implications on mortality despite technical and technological evolution. Practical, ethical, and methodological issues prevent high-quality research in the setting of aspiration and rapid sequence induction/intubation, and significant controversy is ongoing. Patients' position, drugs choice, dosing and timing, use of cricoid force, and a reliable risk assessment are widely debated with significant questions still unanswered. We focus our discussion on three approaches to promote a better understanding of rapid sequence induction/intubation and airway management decision-making. Firstly, we review how we can use qualitative and quantitative assessment of fasting status and gastric content with the point-of-care ultrasound as an integral part of preoperative evaluation and planning. Secondly, we propose using imaging-based mathematical models to study different patient positions and aspiration mechanisms, including identifying aspiration triggers. Thirdly, we promote the development of a global data collection system aiming to obtain precise epidemiological data. Therefore, we fill the gap between evidence-based medicine and experts' opinion through easily accessible and diffused computer-based databases. A better understanding of aspiration epidemiology obtained through focused global data gathering systems, the widespread use of ultrasound-based prandial status evaluation, and development of advanced mathematical models might potentially guide safer airway management decision making in the 21^st century.

Pulmonary Aspiration of Gastric Contents: A Closed Claims Analysis

BACKGROUND

Perioperative pulmonary aspiration of gastric contents has been associated with severe morbidity and death. The primary aim of this study was to identify outcomes and patient and process of care risk factors associated with gastric aspiration claims in the Anesthesia Closed Claims Project. The secondary aim was to assess these claims for appropriateness of care. The hypothesis was that these data could suggest opportunities to reduce either the risk or severity of perioperative pulmonary aspiration.

METHODS

Inclusion criteria were anesthesia malpractice claims in the American Society of Anesthesiologists Closed Claims Project that were associated with surgical, procedural, or obstetric anesthesia care with the year of the aspiration event 2000 to 2014. Claims involving pulmonary aspiration were identified and assessed for patient and process factors that may have contributed to the aspiration event and outcome. The standard of care was assessed for each claim.

RESULTS

Aspiration of gastric contents accounted for 115 of the 2,496 (5%) claims in the American Society of Anesthesiologists Closed Claims Project that met inclusion criteria. Death directly related to pulmonary aspiration occurred in 66 of the 115 (57%) aspiration claims. Another 16 of the 115 (14%) claims documented permanent severe injury. Seventy of the 115 (61%) patients who aspirated had either gastrointestinal obstruction or another acute intraabdominal process. Anesthetic management was judged to be substandard in 62 of the 115 (59%) claims.

CONCLUSIONS

Death and permanent severe injury were common outcomes of perioperative pulmonary aspiration of gastric contents in this series of closed anesthesia malpractice claims. The majority of the patients who aspirated had either gastrointestinal obstruction or acute intraabdominal processes. Anesthesia care was frequently judged to be substandard. These findings suggest that clinical practice modifications to preoperative assessment and anesthetic management of patients at risk for pulmonary aspiration may lead to improvement of their perioperative outcomes.

EDITOR’S PERSPECTIVE

Assessment of remifentanil for rapid sequence induction and intubation in patients at risk of pulmonary aspiration of gastric contents compared to rapid-onset paralytic agents: study protocol for a non-inferiority simple blind randomized controlled trial (the REMICRUSH study)

Background

Rapid-onset paralytic agents are recommended to achieve muscle relaxation and facilitate tracheal intubation during rapid sequence induction in patients at risk of pulmonary aspiration of gastric contents. However, opioids are frequently used in this setting. The study’s objective is to demonstrate the non-inferiority of remifentanil compared to rapid-onset paralytic agents, in association with an hypnotic drug, for tracheal intubation in patients undergoing  procedure under general anesthesia and at risk of pulmonary aspiration of gastric contents.

Methods

The REMICRUSH (Remifentanil for Rapid Sequence Induction of Anaesthesia) study is a multicenter, single-blinded, non-inferiority randomized controlled trial comparing remifentanil (3 to 4 μg/kg) with rapid-onset paralytic agents (succinylcholine or rocuronium 1 mg/kg) for rapid sequence induction in 1150 adult surgical patients requiring tracheal intubation during general anesthesia. Enrolment started in October 2019 in 15 French anesthesia units. The expected date of the final follow-up is October 2021. The primary outcome is the proportion of successful tracheal intubation without major complications. A non-inferiority margin of 7% was chosen. Analyses of the intent-to-treat and per-protocol populations are planned.

Discussion

The REMICRUSH trial protocol has been approved by the ethics committee of The Comité de Protection des Personnes Sud-Ouest et Outre-Mer II and will be carried out according to the principles of the Declaration of Helsinki and the Good Clinical Practice guidelines. The results of this study will be disseminated through presentations at scientific conferences and publications in peer-reviewed journals. The REMICRUSH trial is the first randomized controlled trial powered to investigate whether remifentanil with hypnotics is non-inferior to rapid-onset paralytic agents with hypnotic in rapid sequence induction of anesthesia for full stomach patients considering successful tracheal intubation without major complication.

Trial registration

ClinicalTrials.gov NCT03960801. Registered on May 23, 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05192-x.

[Intraoperative Aspiration]

术中误吸是外科手术中常见的肺部并发症，麻醉和体位是导致术中误吸的主要因素。近年来，围手术期肺保护已受到外科和麻醉医师的广泛关注，如何加速术后康复进程，减少相关并发症发生，显著改善患者预后已成为当前外科治疗的主要目标。本文将以术中误吸为重点，从解剖、病理生理、表现、诊断、处理和预防等方面展开综述。

The Clinical Use of Cricoid Pressure: First, Do No Harm

Application of cricoid pressure (CP) during rapid sequence induction and intubation sequence has been a "standard" of care for many decades, despite limited scientific proof of its efficacy in preventing pulmonary aspiration of gastric contents. While some of the current rapid sequence induction and intubation guidelines recommend its use, other international guidelines do not, and many clinicians argue that there is insufficient evidence to either continue or abandon its use. Recently published articles and accompanying editorials have reignited the debate on the efficacy and safety of CP application and have generated multiple responses that pointed out the various (and significant) limitations of the available evidence. Thus, a critical discussion of available data must be undertaken before making a final clinical decision on such an important patient safety issue. In this review, the authors will take an objective look at the available scientific evidence about the effectiveness and safety of CP in patients at risk of pulmonary aspiration of gastric contents. We suggest that current data are inadequate to impose clinical guidelines on the use of CP because we acknowledge that currently there is not, and there may never be, a method to prevent aspiration in all patients. In addition, we reiterate that a universally accepted medical-legal standard for approaching the high-risk aspiration patient does not exist, discuss the differences in practice between the US and international practitioners regarding use of CP, and propose 5 recommendations on how future studies might be designed to obtain optimal scientific evidence about the effectiveness and safety of CP in patients at risk for pulmonary aspiration.

Impact of Nutrition on Enhanced Recovery After Surgery (ERAS) in Gynecologic Oncology

Enhanced recovery after surgery (ERAS) pathways aim to improve surgical outcomes by applying evidence-based practices before, during, and after surgery. Patients undergoing surgery for gynecologic malignancies are at high risk of complications due to population, patient, disease, and surgical factors. The nutritional status of the patient provides the foundation for recovery after surgery, and opportunities to optimize outcomes exist from the first patient assessment to the early days after surgery. This review highlights the importance of nutritional assessment and intervention during the pre-operative and post-operative periods in the context of ERAS in gynecologic oncology surgery. The emerging role of immunonutrition, carbohydrate loading, and the importance of individualized care are explored. Evidence from studies in gynecologic oncology is presented, where available, and extrapolated from colorectal and other cancer surgery trials when applicable.

Comparative ultrasound study of gastric emptying between an isotonic solution and a nutritional supplement

Background and objectives

Preoperative fasting may lead to undesirable effects in the surgical patient in whom there is a stimulus to ingesting clear liquids until 2 hours before anesthesia. The aim of this study was to evaluate the gastric emptying of two different solutions using ultrasound.

Methods

In a prospective, randomized, blind study, 34 healthy volunteers ingested 200 mL of two solutions without residues in two steps: an isotonic solution with carbohydrates, electrolytes, osmolarity of 292 mOsm.L⁻¹, and 36 kcal; and other nutritional supplementation with carbohydrates, proteins, electrolytes, osmolarity of 680 mO.L⁻¹, and 300 kcal. After 2 hours, a gastric ultrasound was performed to assess the antrum area and gastric volume, and the relation of gastric volume to weight (vol.w⁻¹), whose value above 1.5 mL.kg⁻¹ was considered a risk for bronchoaspiration. A p-value <0.05 was considered statistically significant.

Results

There was a significant difference between all parameters evaluated 2 hours after the ingestion of nutritional supplementation compared to fasting. The same occurred when the parameters between isotonic solution and nutritional supplementation were compared 2 hours after ingestion. Only one patient had vol.w⁻¹ <1.5 mL.kg⁻¹ 2 hours after ingestion of nutritional supplementation; and only one had vol.w⁻¹ >1.5 mL.kg⁻¹ after ingestion of isotonic solution.

Conclusion

This study demonstrated that gastric emptying of equal volumes of different solutions depends on their constitution. Those with high caloric and high osmolarity, and with proteins present, 2 hours after ingestion, increased the gastric volumes, which is compatible with the risk of gastric aspiration.

Endoscopic control of gastric emptying after administration of intravenous erythromycin in an awake patient scheduled for urgent rigid bronchoscopy

Certain interventional pulmonology procedures such as the placement of a tracheal stent or resection of stenosing tracheal tumours require rigid bronchoscopy under general anaesthesia. Unlike an endotracheal tube with a cuff, the rigid bronchoscope only partially protects the airway from bronchoaspiration. For this reason, this procedure is performed on an elective basis in fasted patients. We describe the case of a 60-year-old man with acute respiratory distress requiring emergent rigid bronchoscopy following distal migration of a tracheal stent. One hour before the procedure, the patient had eaten a full meal. Gastric emptying was accelerated by perfusion of intravenous erythromycin and verified by endoscopy with a small diameter gastric endoscope under local anaesthesia. This 1 min procedure was very well tolerated by the patient and allowed to verify with certainty that the stomach was empty. The urgent rigid bronchoscopy for stent retrieval could then be performed safely without any risk of bronchoaspiration.

[Comparative ultrasound study of gastric emptying between an isotonic solution and a nutritional supplement]

BACKGROUND AND OBJECTIVES

Preoperative fasting may lead to undesirable effects in the surgical patient in whom there is a stimulus to ingesting clear liquids until 2hours before anesthesia. The aim of this study was to evaluate the gastric emptying of two different solutions using ultrasound.

METHODS

In a prospective, randomized, blind study, 34 healthy volunteers ingested 200mL of two solutions without residues in two steps: an isotonic solution with carbohydrates, electrolytes, osmolarity of 292 mOsm.L^-1, and 36 kcal; and other nutritional supplementation with carbohydrates, proteins, electrolytes, osmolarity of 680 mO.L^-1, and 300 kcal. After 2hours, a gastric ultrasound was performed to assess the antrum area and gastric volume, and the relation of gastric volume to weight (vol.w^-1), whose value above 1.5mL.kg^-1 was considered a risk for bronchoaspiration. A p-value <0.05 was considered statistically significant.

RESULTS

There was a significant difference between all parameters evaluated 2hours after the ingestion of nutritional supplementation compared to fasting. The same occurred when the parameters between isotonic solution and nutritional supplementation were compared 2hours after ingestion. Only one patient had vol.w^-1 <1.5mL.kg^-1 2hours after ingestion of nutritional supplementation; and only one had vol.w^-1> 1.5mL.kg^-1 after ingestion of isotonic solution.

CONCLUSION

This study demonstrated that gastric emptying of equal volumes of different solutions depends on their constitution. Those with high caloric and high osmolarity, and with proteins present, 2hours after ingestion, increased the gastric volumes, which is compatible with the risk of gastric aspiration.

Analysis of Clinical Indicators of Quality in Patients with Endotracheal intubation

INTRODUCTION

Quality and safety in anaesthesia is usually monitored by analysis of perioperative mortality-morbidity and are influenced by anaesthetic and non-anaesthetic factors.

AIM

This study was conducted to analyse the incidence of clinical indicators of quality in endotracheally intubated patients undergoing general abdominal surgeries and obstetric and gynaecological procedures under general anaesthesia and to determine contributing factors for the same.

MATERIALS AND METHODS

This retrospective study was conducted at our institute over a period of 12 months and 709 case records of patients were reviewed. Patients aged 14 years and more belonging to all ASA groups undergoing abdominal surgeries for general and obstetric and gynaecological causes under General Anaesthesia (GA) with endotracheal intubation posted for both elective and emergency surgeries were included in the study. Demographic details including name, age, sex, hospital number, height, weight, body mass index, type of surgery, nature of surgery, duration, American Society of Anaesthesiologists (ASA) physical status were recorded and presence or absence of clinical indicators of quality (presence of cannot intubate cannot ventilate scenario, occurrence of dental injury, episode of non cardiogenic pulmonary oedema, incidents of residual neuromuscular blockade, existence of aspiration pneumonia, unplanned ICU/HDU admissions, interventions for respiratory/ cardiac arrest, occasions of respiratory distress in the recovery period, occurrence of respiratory arrest within 48 hours and re-intubation) were noted and analysed for all 709 patients.

RESULTS

Total 709 patients were analysed in our study. We found that incidence of ICU admission was 1.83% and that of respiratory distress which needed intervention were 0.56%. A total of 0.28% patients needed reintubation. Residual neuromuscular blockade was seen in 0.28% patients. We did not find any case of respiratory and cardiac arrest and also there was no Cannot Ventilate and Cannot Intubate (CVCI) situation encountered in our study. SPSS for windows (version 17.0) was used as statistical software. Chi-square test was the statistical test for significance. A p-value < 0.05 was considered significant.

CONCLUSION

Proper optimization of patients prior to surgery and optimal perioperative care will result in better quality of care and safety in anaesthesia. Documentation of events and its management during perioperative period will help to know the fields of inappropriate management and thereby improve the quality of care and detect the incidence rates with accuracy and help to formulate protocol for institution.

[Contribution of ultrasonography for the preoperative assessment of gastric contents]

The assessment of the risk of pulmonary aspiration of gastric contents may be difficult in the preoperative period, apart from typical circumstances. The development of ultrasonography in anesthesia and critical care has led to consider ultrasonic imaging of gastric contents for preoperative risk assessment of "full" stomach in clinical practice. Ultrasonography of the body of the stomach allows direct visualization of the gastric contents. However, the stomach is often difficult to identify, particularly when it is empty. Moreover, quantitative assessment of gastric volume is delicate, and no standardized method of ultrasonography of the body of the stomach for preoperative assessment of gastric contents was described. On the contrary, ultrasonography of the antral cross-sectional area, which was initially described for the assessment of gastric emptying as an alternative method to repeated measurements of the variations of antropyloric volume after ingestion of a test meal, is easy to perform and is highly reproducible through using the aorta and the left lobe of the liver as internal landmarks. Qualitative assessment of the gastric antrum allows easily diagnosis of a "full" stomach. The measurement of antral area may allow a more accurate estimate of the presence or absence of gastric contents at risk of lung injury in the event of regurgitation and aspiration (gastric volume >0.8 ml/kg and/or with solid particles), defining the "risk" stomach. The use of antral ultrasonography may help the anesthesiologist to assess the risk of pulmonary aspiration according to clinical history of the patient, in order to choose an appropriate strategy minimizing the occurrence of this complication.

[ARDS and influenza A (H1N1): patients' characteristics and management in intensive care unit. A literature review]

Novel influenza A (H1N1) at the origin of the 2009 pandemic flu developed mainly in subjects of less than 65 years contrary to the seasonal influenza, which usually developed in elderly patients of more than 65 years. Elderly subjects are partly protected by old meetings with close stocks. Influenza A(H1N1) can arise in serious forms within 60 to 80% of cases a fulminant acute respiratory distress syndrome (ARDS) "malignant and fulminant influenza" in subjects without any comorbidity, which makes the gravity and the fear of this influenza. The fact that this influenza A (H1N1) can develop in healthy young patients and evolve in few hours to a severe ARDS with a refractory hypoxemia gave to the foreground the possible interest of the recourse to extracorporeal oxygenation (ECMO) in some selected severe ARDS (5-10%). The first publications of patients admitted in intensive care unit (ICU) for severe influenza A (H1N1) often associated to an ARDS reported a mortality rate from 15 to 40%. This mortality variability may be explained in part by different studied populations, ARDS characteristics and human and material resources in the ICUs between the countries. Indeed, the highest mortality rates (30-40%) have been reported by in Mexico which were affected the first by pandemic flu and which were not prepared. A bacterial pneumonia was associated to H1N1 influenza in approximately 30% of the cases as at admission in ICU or following the days of the admission justifying an early antibiotherapy associated to the antiviral treatment by oseltamivir (Tamiflu). Obesity, pregnancy and respiratory diseases (asthma, COPD) seem to be associated to the development of a severe viral pneumonia due to influenza A (H1N1) often with ARDS. Older age, high APACHE II and SOFA scores and a delay of initiation of the antiviral treatment by oseltamivir are associated to higher morbidity and mortality. Other analyses of the results obtained from the first published papers included more patients and future studies would permitted to better define the role of therapeutics such as steroids and ECMO.