Reducing the carbon footprint of general anaesthesia: a comparison of total intravenous anaesthesia vs. a mixed anaesthetic strategy in 47,157 adult patients.

Global warming is a major public health concern. Volatile anaesthetics are greenhouse gases that increase the carbon footprint of healthcare. Modelling studies indicate that total intravenous anaesthesia is less carbon intensive than volatile anaesthesia, with equivalent quality of care. In this observational study, we aimed to apply the findings of previous modelling studies to compare the carbon footprint per general anaesthetic of an exclusive TIVA strategy vs. a mixed TIVA-volatile strategy. This comparative retrospective study was conducted over 2 years in two French hospitals, one using total intravenous anaesthesia only and one using a mixed strategy including both intravenous and inhalation anaesthetic techniques. Based on pharmacy procurement records, the quantity of anaesthetic sedative drugs was converted to carbon dioxide equivalents. The primary outcome was the difference in carbon footprint of hypnotic drugs per intervention between the two strategies. From 1 January 2021 to 31 December 2022, 25,137 patients received general anaesthesia in the hospital using the total intravenous anaesthesia strategy and 22,020 in the hospital using the mixed strategy. The carbon dioxide equivalent footprint of hypnotic drugs per intervention in the hospital using the total intravenous anaesthesia strategy was 20 times lower than in the hospital using the mixed strategy (emissions of 2.42 kg vs. 48.85 kg carbon dioxide equivalent per intervention, respectively). The total intravenous anaesthesia strategy significantly reduces the carbon footprint of hypnotic drugs in general anaesthesia in adult patients compared with a mixed strategy. Further research is warranted to assess the risk-benefit ratio of the widespread adoption of total intravenous anaesthesia.

Lung ultrasound for early diagnosis of postoperative need for ventilatory support: a prospective observational study.

Pulmonary complications have a significant impact on morbidity and mortality in patients after major surgery. Lung ultrasound can be used at the bed-side, and has gained widespread acceptance in the intensive care unit. We conducted a prospective study to evaluate whether lung ultrasound could be used as a predictive marker for postoperative ventilatory support in high-risk surgical patients. We included 109 patients admitted to the intensive care unit while having mechanical ventilation of the lungs following major surgery. The PaO2 /FI O2 ratio was calculated on admission and an ultrasound examination performed, including: lung ('lung ultrasound score', number of consolidated lung areas); cardiac (mitral flow); and inferior vena cava imaging (diameter and respiratory variation). Respiratory outcomes included: the need for ventilation support (mechanical ventilation, non-invasive ventilation or high-flow nasal cannula oxygen therapy); acute respiratory distress syndrome; cardiogenic pulmonary oedema; and early or late pulmonary infection. Patients with a lung ultrasound score ≥ 10 had a lower PaO2 /FI O2 ratio, and needed more postoperative ventilatory support, than patients with lung ultrasound score < 10. Twenty patients had acute respiratory distress syndrome, and 14 had cardiogenic pulmonary oedema. The presence of ≥ 2 areas of consolidated lung was associated with a lower PaO2 /FI O2 ratio, postoperative ventilatory support, longer intensive care stay and episodes of ventilator-associated pneumonia requiring antibiotics. Our results suggest that at intensive care unit admission, lung ultrasound scoring and detection of atelectasis can predict postoperative pulmonary outcomes after major visceral surgery, and could enhance bed-side decision making.

Reliability of gastric suctioning compared with ultrasound assessment of residual gastric volume: a prospective multicentre cohort study.

We aimed to compare the reliability of aspiration via a nasogastric tube with ultrasound for assessment of residual gastric volume. Sixty-one adult patients who were mechanically ventilated and received continuous enteral feeding through a nasogastric tube for > 48 h were included. A first qualitative and quantitative ultrasound examination of the gastric antrum was followed by gastric suctioning, performed by an operator blinded to the result of the ultrasound examination. A second ultrasound examination was performed thereafter, followed by re-injection of the aspirated gastric contents (≤ 250 ml) into the stomach. A third ultrasound assessment was then immediately performed. If the suctioned volume was ≥ 250 ml, 250 mg erythromycin was infused over 30 min. A fourth ultrasound was performed 90 min after the third. Sixty (98%) patients had a qualitatively assessed full stomach at first ultrasound examination vs. 52 (85%) after gastric suctioning (p = 0.016). The calculated gastric volume significantly decreased after gastric suctioning, without a significant decrease in the number of patients with volume ≥ 250 ml. Four of the nine patients with calculated gastric volume ≥ 250 ml had vomiting within the last 24 h (p = 0.013). The antral cross-sectional area significantly decreased between the third and the fourth ultrasound examination (p = 0.015). Erythromycin infusion did not make a significant difference to gastric volume (n = 10). Our results demonstrate that gastric suctioning is not a reliable tool for monitoring residual gastric volume. Gastric ultrasound is a feasible and promising tool for gastric volume monitoring in clinical practice.

Diagnostic point-of-care ultrasound: applications in obstetric anaesthetic management.

Complications during pregnancy are not frequent, but may occur abruptly. Point-of-care ultrasound is a non-invasive, non-ionising diagnostic tool that is available at the bed-side when complications occur. This review covers the use of ultrasound in various clinical situations. Gastric ultrasound can identify stomach contents that put the woman at risk for pulmonary aspiration. In the future, this tool will probably be used routinely before induction of anaesthesia to determine the presence of stomach contents above a particular risk threshold. Difficult tracheal intubation, and the potential for 'can't intubate, can't oxygenate', is more frequent in pregnant women. Point-of-care ultrasound of the airway allows accurate identification of the cricothyroid membrane, permitting rapid and safer establishment of front-of-neck airway access. Combined cardiac and lung ultrasound can determine the potential risk:benefit of fluid administration in the pregnant patient. Such prediction is of critical importance, given the tendency of pregnant women to develop pulmonary oedema. Combined echocardiography and lung ultrasound can be combined with ultrasound of the leg veins to differentiate between the various causes of acute respiratory failure, and guide treatment in this situation. Finally, as shown in the general population, multi-organ point-of-care ultrasound allows early diagnosis of the main causes of circulatory failure and cardiac arrest at the bed-side. As the importance of point-of-care ultrasound in critical patients is increasingly recognised, it is emerging as an important tool in the therapeutic armoury of obstetric anaesthetists.

Can point-of-care ultrasound predict spinal hypotension during caesarean section? A prospective observational study.

Spinal anaesthesia for elective caesarean section is associated with maternal hypotension, secondary to alteration of sympathetic tone and hypovolemia, in up to 70% of cases. Measurement of the subaortic variation in the velocity time integral (VTI) after passive leg raising allows prediction of fluid responsiveness. Our objective, in this prospective single-centre observational study, was to assess the ability of change in VTI after 45° passive leg raising to predict hypotension after spinal anaesthesia. Ultrasound measurements were performed just before elective caesarean section. Anaesthesia, intravenous coloading and prophylactic vasopressor treatment were standardised according to current guidelines. We studied 40 women. Hypotension occurred in 17 (45%) women. The area (95%CI) under the receiver operating characteristics (ROC) curve for the prediction of spinal hypotension was 0.8 (0.6-0.9; p = 0.0001). Seventeen women had a change in VTI with leg elevation ≤ 8%, which was predictive for not developing hypotension, and 11 had a change ≥ 21%, predictive for hypotension. The grey zone between 8% and 21%, with inconclusive values, included 12 women. We suggest that cardiac ultrasound provides characterisation of the risk of hypotension following spinal anaesthesia at elective caesarean section, and therefore may allow individualised strategies for prevention and management.

Rapid diagnostic test and use of antibiotic against methicillin-resistant Staphylococcus aureus in adult intensive care unit.

Ventilator-associated pneumonia (VAP) due to methicillin-resistant Staphylococcus aureus (MRSA) is associated with excess mortality and costs. Molecular biology test allows rapid identification of MRSA in sputum with high negative predictive value. We hypothesized that use of a rapid diagnostic test in patients with suspected VAP was associated with reduced use of antibiotics directed against MRSA. This retrospective, observational study was conducted in a polyvalent intensive care unit (ICU) of a university hospital. We compared two periods: before (2007-2010) and after (2010-2015) the implementation of a rapid diagnostic test, which uses RT-PCR to detect pathogens in 60 minutes. The primary endpoint was the effect on the empirical use of anti-MRSA antibiotics. The second endpoint was the effect of this strategy on the cost regarding antibiotic treatment. The first group included 120 suspected VAP (88 patients) and the second group 121 suspected VAP (89 patients). Empirical use of vancomycin and linezolid decreased by 50 % between the two periods. Twenty-seven VAP (22 %) were treated with an anti-MRSA treatment between 2007 and 2010, and 13 (11 %) between 2010 and 2015 (p = 0.04). The mean cost of anti-MRSA treatment by patients in the first group was 63 ± 223 €, and 13 ± 52 € in the second group (p < 0.001). This study shows that a rapid diagnostic test was associated with reduced use and cost of anti-MRSA antibiotics in patients with suspected VAP. These results should be confirmed by further multicenter prospective studies.

Ultrasonographic measurement of antral area for estimating gastric fluid volume in parturients.

BACKGROUND: The aim of this prospective observational study was to assess the performance of ultrasonographic gastric antral area (GAA) to predict gastric fluid volumes of >0.4, >0.8 and >1.5 ml kg(-1), in fasted women in established labour. METHODS: A first ultrasound examination of the antrum was performed, in order to confirm gastric vacuity by using a qualitative score. Baselines GAA measurements were obtained in both supine and right lateral decubitus positions. Thereafter, parturients were allowed to drink clear fluids only. Measurement of GAA was repeated 15 min after last fluid intake, in both supine and right lateral positions. Receiver operating characteristics (ROC) curves were constructed to determine the accuracy of GAA to diagnose ingested volumes of >0.4, >0.8 and >1.5 ml kg(-1). RESULTS: Data from forty parturients were analysed. The areas under the ROC curves ranged from 80% to 86%. The cut-off value for antral area measured in supine position, to detect a volume >0.4 ml kg(-1), was 387 mm(2), with a sensitivity of 87%, a specificity of 70% and a negative predictive value of 85%. A cut-off value of 608 mm(2) predicted a fluid volume >1.5 ml kg(-1), with a specificity of 94%, a sensitivity of 75% and a negative predictive value of 92%. CONCLUSIONS: This study provides cut-off values for GAA that could be used in addition to the qualitative assessment of the antrum to define a full stomach in labouring patients.

Evaluation of pulse pressure variation validity criteria in critically ill patients: a prospective observational multicentre point-prevalence study.

BACKGROUND: Respiratory variation in pulse pressure (ΔPP) is commonly used to predict the fluid responsiveness of critically ill patients. However, some researchers have demonstrated that this measurement has several limitations. The present study was designed to evaluate the proportion of patients satisfying criteria for valid application of ΔPP at a given time-point. METHODS: A 1 day, prospective, observational, point-prevalence study was performed in 26 French intensive care units (ICUs). All patients hospitalized in the ICUs on the day of the study were included. The ΔPP validity criteria were recorded prospectively and defined as follows: (i) mechanical ventilation in the absence of spontaneous respiration; (ii) regular cardiac rhythm; (iii) tidal volume ≥8 ml kg(-1) of ideal body weight; (iv) a heart rate/respiratory rate ratio >3.6; (v) total respiratory system compliance ≥30 ml cm H2O(-1); and (vi) tricuspid annular peak systolic velocity ≥0.15 m s(-1). RESULTS: The study included 311 patients with a Simplified Acute Physiology Score II of 41 (39-43). Overall, only six (2%) patients satisfied all validity criteria. Of the 170 patients with an arterial line in place, only five (3%) satisfied the validity criteria. During the 24 h preceding the study time-point, fluid responsiveness was assessed for 79 patients. ΔPP had been used to assess fluid responsiveness in 15 of these cases (19%). CONCLUSIONS: A very low percentage of patients satisfied all criteria for valid use of ΔPP in the evaluation of fluid responsiveness. Physicians must consider limitations to the validity of ΔPP before using this variable.

Lung ultrasound-guided management of acute breathlessness during pregnancy.

Lung ultrasonography is a standard tool in the intensive care unit and in emergency medicine, but has not been described in the particular setting of the labour ward. During pregnancy, acute respiratory failure and pulmonary oedema are not uncommon life-threatening events. We present two case reports outlining the potential of lung ultrasonography in parturients. In case 1, lung ultrasonography allowed early diagnosis and treatment of acute dyspnoea in a parturient admitted for suspected asthma exacerbation. Lung ultrasonography revealed a 'B-pattern' of vertical lines radiating into the lung tissue, indicating severe pulmonary oedema complicating previously undiagnosed pre-eclampsia. In case 2, a pre-eclamptic patient was managed with combined transthoracic echocardiography and lung ultrasonography. The accuracy of lung ultrasonography in detecting interstitial oedema at a pre-clinical stage allowed adequate fluid resuscitation in this patient who had a high risk of alveolar pulmonary oedema. We believe that these cases strongly support the prospective validation of lung ultrasound for management of lung disorders in pregnant women.

The need for maternal critical care education, point-of-care ultrasound and critical care echocardiography in obstetric anesthesiologists training.

Globally, the increase in medically complex obstetric patients is challenging the educational approach and clinical management of critically ill obstetric patients. This increase in medical complexity calls into question the educational paradigm in which future physicians are trained. Obstetric anesthesiologists, physician experts in the perio-perative planning and management of complex obstetric patients, represent an essential workforce in the strategies to address maternal mortality. Unfortunately, the development of peri-operative medicine and maternal critical care curricula has only received minor attention in most countries. Proposed guidelines and models highlight the existing need for tiered maternity care services in which critical care infrastructure plays a central role in the delivery of high-risk peripartum care. Therefore, the development of maternal critical care models designed to prepare obstetric anesthesiologists for the clinical challenges of a medically complex patient are warranted. Key critical care topics such as advanced ultrasonography, with the inclusion of quantitative echocardiographic assessments into obstetric anesthesiology educational curricula, will serve to better prepare physicians for the realities of an increasingly complex pregnant patient population, and further reinforce the critical care infrastructure detailed in the Levels of Maternal Care consensus. Despite an increasingly complex obstetric patient population, heterogeneity of maternal critical care practices exists across the globe, warranting standardization and further development of proposed curricula.

Performance of non-invasive stroke volume variation during passive leg raising as a predictor of hypotension following induction of spinal anesthesia for elective cesarean delivery: a single cohort study.

BACKGROUND: Spinal anesthesia for cesarean delivery is accompanied by hypotension in up to 70% of cases. To date, there is no gold standard for predicting hypotension after spinal anesthesia for cesarean delivery. The Clearsight™ device is a non-invasive system that uses a digital cuff to calculate stroke volume. We hypothesized that stroke volume variation induced with passive leg raising before spinal anesthesia for elective cesarean delivery could predict the occurrence of hypotension. METHODS: We conducted a prospective observational study, including third trimester parturients undergoing elective cesarean delivery with spinal anesthesia. We analyzed the stroke volume variation performance for predicting hypotension. Stroke volume was collected in the semi-recumbent position (baseline) and during passive leg raising before spinal anesthesia. Systolic arterial blood pressure measurement was followed for 15 min after spinal anesthesia. Hypotension was defined as a ≥20% decrease from the baseline measurement. All parturients received appropriate hypotension prophylaxis. RESULTS: Data from 42 parturients were analyzed. Hypotension occurred in 45%. The area-under-the curve for predicting hypotension using the stroke volume variation was 0.83 (95% CI 0.68 to 0.98; P=0.001). The best cut-off value for predicting hypotension was 7%, having a sensitivity of 87% (95% CI 0.70 to 0.99) and a specificity of 83% (95% CI 0.69 to 0.97). CONCLUSION: In our study of third trimester parturients undergoing cesarean delivery and receiving appropriate hypotension prophylaxis, a digital non-invasive monitoring device of stroke volume variation analysis was useful for predicting the occurrence of hypotension after spinal anesthesia.

Clearsight™ use for haemodynamic monitoring during the third trimester of pregnancy - a validation study.

BACKGROUND: We assessed the validity of Clearsight™ as a non-invasive cardiac output and stroke volume monitoring device, comparing it with transthoracic echocardiography measurements during the third trimester of pregnancy. METHODS: Measurements obtained from Clearsight™ were compared with those from echocardiography as the gold standard. The precision and accuracy of the Clearsight™ was measured using the Bland and Altman method. Clinical agreement with echocardiography was assessed using the agreement tolerability index. RESULTS: Measurements were recorded from 44 pregnant women with a median [IQR range] gestational age of 33 [30-37] weeks. We found that Clearsight™ measurements presented a systematic overestimation of cardiac output, with mean bias [CI 95%] of 2.7 [2.3-3.0] L/min, with limits of agreement of  -0.1 to 5.4 L/min. It overestimated stroke volume, with a bias of 29.5 [25.0-33.4] mL and a limit of agreement of -1.6 to 60.1 mL. In addition, the analysis of cardiac output showed a percentage of error of 41% and intra-class correlation [CI 95%] of 0.37 [0.17 to 0.53, P <0.001]. For stroke volume, the percentage of error was 40% and intra-class correlation 0.16 [-0.1 to 0.34; P=0.27]. We found that agreement tolerability index scores were unacceptable. We evaluated the ability of the device to track changes in cardiac output by inducing a left lateral decubitus position, but the analysis was inconclusive. CONCLUSION: The agreement between Clearsight™ and the echocardiography measurements of cardiac output and stroke volume were not within an acceptable range in the third trimester of pregnancy.

Use of speckle-tracking strain in preload-dependent patients, need for cautious interpretation!

BACKGROUND: In critical patients, left ventricular ejection fraction and fractional shortening are used to reflect left ventricular systolic function. An emerging technique, two-dimensional-strain echocardiography, allows assessment of the left ventricle systolic longitudinal deformation (global longitudinal strain) and the speed at which this deformation occurs (systolic strain rate). This technique is of increasing use in critical patients in intensive care units and in the peri-operative period where preload constantly varies. Our objective, in this prospective single-center observational study, was to evaluate the effect of fluid resuscitation on two-dimensional-strain echocardiography measurements in preload-dependent critically ill patients. We included 49 patients with preload dependence attested by an increase of at least 10% in the left ventricular outflow track velocity-time integral measured by echocardiography during a passive leg raising maneuver. Echocardiography was performed before fluid resuscitation (echocardiography 1) and after preload independency achievement (echocardiography 2). RESULTS: Two-dimensional-strain echocardiography was feasible in 40 (82%) among the 49 patients. With preload dependence correction, the absolute value of global longitudinal strain and systolic strain rate was significantly increased from, respectively, - 13.3 ± 3.5 to - 18.4% ± 4.5 (p < 0.01) and - 1.11 s-1 ± 0.29 to - 1.55 s-1 ± 0.55 (p < 0.001). The fluid resuscitation affects GLS and SSR in preload-dependent patients, with a shift, for GLS, from pathological to normal values. CONCLUSION: In critically ill patients, the assessment of the systolic function by two-dimensional-strain echocardiography needs prior evaluation of preload dependency, in order to adequately interpret this variable. Future studies should assess the ability of global longitudinal strain to guide fluid management in the critically ill patients.

[Maternal deaths due to infectious cause, results from the French confidential enquiry into maternal deaths, 2010-2012]. / Mortalité maternelle par infection, résultats de l'ENCMM, France 2010­2012.

Over the period 2010-2012, maternal mortality from infectious causes accounted for 5% of maternal deaths by direct causes and 16% of maternal deaths by indirect causes. Among the 22 deaths caused by infection occurred during this period, 6 deaths were attributed to direct causes from genital tract origin, confirming thus the decrease in direct maternal deaths by infection during the last ten years. On the contrary, indirect maternal deaths by infection, from extragenital origin, doubled during the same period, with 16 deaths in the last triennium, dominated by winter respiratory infections, particularly influenza: the 2009-2010 influenza A (H1N1) virus pandemic was the leading cause of indirect maternal mortality by infection during the studied period. The main infectious agents involved in maternal deaths from direct causes were Streptococcus A, Escherichia Coli and Clostridium perfringens: these bacterias were responsible for toxic shock syndrome, severe sepsis, secondary in some cases to cellulitis or necrotizing fasciitis. Of the 6 deaths due to direct infection, 4 were considered avoidable because of inadequate management: delayed or missed diagnosis, delayed or inadequate initiation of a specific medical and/or surgical treatment. Of the 16 indirect maternal deaths due to infection causes, the most often involved infectious agents were influenza A (H1N1) virus and Streptococcus pneumonia with induced purpura fulminans: the absence of influenza vaccination during pregnancy, delayed diagnosis and emergency initiation of a specific treatment, were the main contributory factors to these deaths and their avoidability in 70% of the cases analyzed.

[Maternal deaths due to hypertensive disorders. Results from the French confidential enquiry into maternal deaths, 2010-2012]. / Morts maternelles par complications hypertensives. Résultats de l'enquête confidentielle française sur la mortalité maternelle, 2010­2012.

Between 2010 and 2012, the rate of maternal death caused by hypertensive disorders (0,5/100,000 living birth) was reduced by 50% compared to the 2007-2009 period. Hypertensive disorders were responsible from 5% of maternal deaths and from 10% of direct maternal mortality. Eleven deaths happened during the postpartum period but 9 hypertensive complications began before delivery. Seventy percent of these deaths seem to be avoidable. The main causes of suboptimal management were: unappropriated or insufficient obstetrical and anesthetic treatments, undiagnosed HELLP syndrome and subcapsular liver hematoma, delayed treatment. The analysis of these maternal deaths gave the opportunity to stress some major lessons to optimize medical management in case of hypertensive diseases during pregnancy: abdominal symptoms during third trimester of pregnancy lead to search hypertensive disorders; HELLP syndrome with severe anemia indicate to carry out abdominal ultrasound.

Implementation of lung ultrasound in polyvalent intensive care unit: Impact on irradiation and medical cost.

OBJECTIVE: To determine the effect of implementing a daily lung ultrasound round on the number of chest radiographs and chest computed tomography (CT) scans in a polyvalent intensive care unit (ICU). STUDY DESIGN: Retrospective study comparing two consecutive periods. PATIENTS: All patients hospitalized for longer than 48 hours in a polyvalent ICU. METHODS: Implementation of a daily lung ultrasound round after a short educational program. The number of chest radiographs and chest CT scans and the patient outcome were measured before (group PRE) and after (group POST) the implementation of a daily lung ultrasound round. RESULTS: No demographic difference was found between the two groups, with the exception of a higher severity score in the group POST. For each ICU stay, the number of chest radiographs was 10.3 ± 12.4 in the group PRE and 7.7 ± 10.3 in the group POST, respectively (P<0.005) The number of chest CT scans was not reduced in the group POST, as compared with the group PRE (0.5 ± 0.7 CT scan/patient/ICU stay versus 0.4 ± 0.6 CT scan/patient/ICU stay, P=0.01). The ICU mortality was similar in both groups (21% versus 22%, P=0.75) CONCLUSION: The implementation of a daily lung ultrasound round was associated with a reduction in radiation exposure and medical cost without altering patient outcome.

[Meningitis to Candida albicans at the adult, use of the new diagnosis methods]. / Méningite à Candida albicans chez l'adulte, apport des nouveaux moyens diagnostiques.

Candida albicans or non-albicans are a frequent source of infection but seldom displayed in cerebrospinal fluid although responsible of an important number of nosocomial meningitis. Diagnosis is difficult which often delays treatment, which in turn hinders prognostic. This clinical case shows a patient afflicted with a deadly C. albicans meningitis and allows us to focus on new diagnostic tools and advice against this infection.