Exploring ultrasonographic diaphragmatic function in perioperative anesthesia setting: A comprehensive narrative review.

The ultrasound study of diaphragm function represents a valid method that has been extensively studied in recent decades in various fields, especially in intensive care, emergency, and pulmonology settings. Diaphragmatic function is pivotal in these contexts due to its crucial role in respiratory mechanics, ventilation support strategies, and overall patient respiratory outcomes. Dysfunction or weakness of the diaphragm can lead to respiratory failure, ventilatory insufficiency, and prolonged mechanical ventilation, making its assessment essential for patient management and prognosis in critical care and emergency medicine. While several studies have focused on diaphragmatic functionality in the context of intensive care, there has been limited attention within the field of anesthesia. The ultrasound aids in assessing diaphragmatic dysfunction (DD) by measuring muscle mass and contractility and their potential variations over time. Recent advancements in ultrasound imaging allow clinicians to evaluate diaphragm function and monitor it during mechanical ventilation more easily. In the context of anesthesia, early studies have shed light on the patho-physiological mechanisms of diaphragm function during general anesthesia. In contrast, more recent research has centered on evaluating diaphragmatic functionality at various phases of general anesthesia and by comparing diverse types of procedures or anatomical position during surgery. The objectives of this current review are to highlight the use of diaphragm ultrasound for the evaluation of diaphragmatic function during perioperative anesthesia and surgery. Specifically, we aim to examine the effects of anesthetic agents, surgical techniques, and anatomical positioning on diaphragmatic function. We explore how ultrasound aids in assessing DD by measuring muscle mass and contractility, as well as their potential variations over time. Additionally, we will discuss recent advancements in ultrasound imaging that allow clinicians to evaluate diaphragm function and monitor it during mechanical ventilation more easily.

Generalized music therapy to reduce neuroactive drug needs in critically ill patients. Study protocol for a randomized trial.

BACKGROUND: Critically ill patients are exposed to several physical and emotional stressors, needing analgesic and sedative drugs to tolerate invasive procedures and the harsh intensive care unit (ICU) environment. However, this pharmacological therapy presents several side effects: guidelines suggest using a light sedation target, keeping critically ill patients calm, conscious, and cooperative. Personalized music therapy (MT) can reduce stress and anxiety, decreasing the need for drugs. The aim of the current investigation is to compare different approaches for MT in the ICU: a personalized approach, with music selected by patients/families and listened through headphones, or a generalized approach, with ambient music chosen by a music therapist and transmitted through speakers. PRIMARY OUTCOME: number of days "free from neuroactive drugs" in the first 28 days after ICU admission. SECONDARY OUTCOMES: total amount of neuroactive drugs (midazolam, propofol, morphine, fentanyl, haloperidol), stress during ICU stay (sleep at night, anxiety and agitation, use of physical restraints, stressors evaluated at discharge), the feasibility of generalized MT (interruptions requested by staff members and patients/families). METHODS: Randomized, controlled trial with three groups of critically ill adults: a control group, without MT; a personalized MT group, with music for at least 2 h per day; a generalized MT group, with music for 12.5 h/day, subdivided into fifteen 50-min periods. DISCUSSION: One hundred fifty-three patients are expected to be enrolled. This publication presents the rationale and the study methods, particularly the strategies used to build the generalized MT playlist. From a preliminary analysis, generalized MT seems feasible in the ICU and is positively received by staff members, critically ill patients, and families. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03280329. September 12, 2017.

Presepsin in Critical Illness: Current Knowledge and Future Perspectives.

The accurate identification of infections is critical for effective treatment in intensive care units (ICUs), yet current diagnostic methods face limitations in sensitivity and specificity, alongside cost and accessibility issues. Consequently, there is a pressing need for a marker that is economically feasible, rapid, and reliable. Presepsin (PSP), also known as soluble CD14 subtype (sCD14-ST), has emerged as a promising biomarker for early sepsis diagnosis. PSP, derived from soluble CD14, reflects the activation of monocytes/macrophages in response to bacterial infections. It has shown potential as a marker of cellular immune response activation against pathogens, with plasma concentrations increasing during bacterial infections and decreasing post-antibiotic treatment. Unlike traditional markers such as procalcitonin (PCT) and C-reactive protein (CRP), PSP specifically indicates monocyte/macrophage activation. Limited studies in critical illness have explored PSP's role in sepsis, and its diagnostic accuracy varies with threshold values, impacting sensitivity and specificity. Recent meta-analyses suggest PSP's diagnostic potential for sepsis, yet its standalone effectiveness in ICU infection management remains uncertain. This review provides a comprehensive overview of PSP's utility in ICU settings, including its diagnostic accuracy, prognostic value, therapeutic implications, challenges, and future directions.

Managing Severe Cancer Pain with Oxycodone/Naloxone Treatment: A Literature Review Update.

Severe cancer pain substantially affects patients' quality of life, increasing the burden of the disease and reducing the disability-adjusted life years. Although opioid analgesics are effective, they may induce opioid-induced bowel dysfunction (OIBD). Oxycodone/naloxone combination therapy has emerged as a promising approach to mitigate opioid-induced constipation (OIC) while providing effective pain relief. This review provides an updated analysis of the literature of the last decade regarding the use of oxycodone/naloxone in the management of severe cancer pain. Through a comprehensive search of databases, studies focusing on the efficacy, safety, and patient experience of oxycodone/naloxone's prolonged release in severe cancer pain management were identified. Furthermore, the literature discusses the mechanism of action of naloxone in mitigating OIC without compromising opioid analgesia. Overall, the evidence suggests that oxycodone/naloxone combination therapy offers a valuable option for effectively managing severe cancer pain while minimizing opioid-induced constipation, thereby improving patients' quality of life. However, further research is needed to optimize dosing regimens, evaluate long-term safety, and assess patient outcomes in diverse cancer populations.

A Secondary Retrospective Analysis of the Predictive Value of Neutrophil-Reactive Intensity (NEUT-RI) in Septic and Non-Septic Patients in Intensive Care.

BACKGROUND: Effective identification and management in the early stages of sepsis are critical for achieving positive outcomes. In this context, neutrophil-reactive intensity (NEUT-RI) emerges as a promising and easily interpretable parameter. This study aimed to assess the predictive value of NEUT-RI in diagnosing sepsis and to evaluate its prognostic significance in distinguishing 28-day mortality outcomes. MATERIALS: This study is a secondary, retrospective, observational analysis. Clinical data upon ICU admission were collected. We enrolled septic patients and a control group of critically ill patients without sepsis criteria. The patients were divided into subgroups based on renal function for biomarker evaluation with 28-day outcomes reported for septic and non-septic patients. RESULTS: A total of 200 patients were included in this study. A significant difference between the "septic" and "non-septic" groups was detected in the NEUT-RI plasma concentration (53.80 [49.65-59.05] vs. 48.00 [46.00-49.90] FI, p < 0.001, respectively). NEUT-RI and procalcitonin (PCT) distinguished between not complicated sepsis and septic shock (PCT 1.71 [0.42-12.09] vs. 32.59 [8.83-100.00], <0.001 and NEUT-RI 51.50 [47.80-56.30] vs. 56.20 [52.30-61.92], p = 0.005). NEUT-RI, PCT, and CRP values were significantly different in patients with "renal failure". NEUT-RI and PCT at admission in the ICU in the septic group were higher in patients who died (58.80 [53.85-73.10] vs. 53.05 [48.90-57.22], p = 0.005 and 39.56 [17.39-83.72] vs. 3.22 [0.59-32.32], p = 0.002, respectively). Both NEUT-RI and PCT showed a high negative predictive value and low positive predictive value. CONCLUSIONS: The inflammatory biomarkers assessed in this study offer valuable support in the early diagnosis of sepsis and could have a possible role in anticipating the outcome. NEUT-RI elevation appears particularly promising for early sepsis detection and severity discrimination upon admission.

Foot drop in critically ill patients: a narrative review of an elusive complication with intricate implications for recovery and rehabilitation.

Foot drop is a condition characterized by the inability to lift the foot upwards towards the shin bone. This condition may affect a proportion of critically ill patients, impacting on their recovery after the acute phase of the illness. The occurrence of foot drop in critical care patients may result from various underlying causes, including neurological injuries, muscular dysfunction, nerve compression, or vascular compromise. Understanding the etiology and assessing the severity of foot drop in these patients is essential for implementing appropriate management strategies and ensuring better patient outcomes. In this comprehensive review, we explore the complexities of foot drop in critically ill patients. We search for the potential risk factors that contribute to its development during critical illness, the impact it has on patients' functional abilities, and the various diagnostic techniques adopted to evaluate its severity. Additionally, we discuss current treatment approaches, rehabilitation strategies, and preventive measures to mitigate the adverse effects of foot drop in the critical care setting. Furthermore, we explore the roles of critical care physical therapists, neurologists, and other healthcare professionals in the comprehensive care of patients with foot drop syndrome and in such highlighting the importance of a multidisciplinary approach.

Metabolic Support in Acute Respiratory Distress Syndrome: A Narrative Review.

Nutritional support for acute respiratory distress syndrome (ARDS) patients shares metabolic notions common to other critically ill conditions. Nevertheless, it generates specific concern regarding the primary limitation of oxygen supply and the complications of carbon dioxide elimination, as well as the significant metabolic alterations due to the body's response to illness. In the present narrative review, after briefly summarizing the pathophysiology of critical illness stress response and patients' metabolic requirements, we focus on describing the characteristics of metabolic and artificial nutrition in patients with acute respiratory failure. In patients with ARDS, several aspects of metabolism assume special importance. The physiological effects of substrate metabolism are described for this setting, particularly regarding energy consumption, diet-induced thermogenesis, and the price of their clearance, transformation, and storage. Moreover, we review the possible direct effects of macronutrients on lung tissue viability during ARDS. Finally, we summarize the noteworthy characteristics of metabolic control in critically ill patients with ARDS and offer a suggestion as to the ideal methods of metabolic support for this problem.

The Potential Role of Neutrophil-Reactive Intensity (NEUT-RI) in the Diagnosis of Sepsis in Critically Ill Patients: A Retrospective Cohort Study.

The diagnosis of sepsis is often difficult and belated, substantially increasing mortality in affected patients. Its early identification allows for us to choose the most appropriate therapies in the shortest time, improving patients' outcomes and eventually their survival. Since neutrophil activation is an indicator of an early innate immune response, the aim of the study was to evaluate the role of Neutrophil-Reactive Intensity (NEUT-RI), which is an indicator of their metabolic activity, in the diagnosis of sepsis. Data from 96 patients consecutively admitted to the Intensive Care Unit (ICU) were retrospectively analyzed (46 patients with and 50 without sepsis). Patients with sepsis were further divided between sepsis and septic shock according to the severity of the illness. Patients were subsequently classified according to renal function. For the diagnosis of sepsis, NEUT-RI showed an AUC of >0.80 and a better negative predictive value than Procalcitonin (PCT) and C-reactive protein (CRP) (87.4% vs. 83.9% and 86.6%, p = 0.038). Unlike PCT and CRP, NEUT-RI did not show a significant difference within the "septic" group between patients with normal renal function and those with renal failure (p = 0.739). Similar results were observed among the "non-septic" group (p = 0.182). The increase in NEUT-RI values could be useful in the early ruling-out of sepsis, and it does not appear to be influenced by renal failure. However, NEUT-RI has not proved to be efficient in discriminating the severity of sepsis at the time of admission. Larger, prospective studies are needed to confirm these results.

The Effects of Positive End Expiratory Pressure and Lung Volume on Diaphragm Thickness and Thickening.

Introduction: Diaphragm dysfunction is common in patients undergoing mechanical ventilation. The application of positive end-expiratory pressure (PEEP) and the varying end-expiratory lung volume cause changes in diaphragm geometry. We aimed to assess the impact of the level of PEEP and lung inflation on diaphragm thickness, thickening fraction and displacement. Methods: An observational study in a mixed medical and surgical ICU was conducted. The patients underwent a PEEP-titration trial with the application of three random levels of PEEP: 0 cmH2O (PEEP0), 8 cmH2O (PEEP8) and 15 cmH2O (PEEP15). At each step, the indices of respiratory effort were assessed, together with arterial blood and diaphragm ultrasound; end-expiratory lung volume was measured. Results: 14 patients were enrolled. The tidal volume, diaphragm displacement and thickening fraction were significantly lower with higher levels of PEEP, while both the expiratory and inspiratory thickness increased with higher PEEP levels. The inspiratory effort, as evaluated by the esophageal pressure swing, was unchanged. Both the diaphragm thickening fraction and displacement were significantly correlated with inspiratory effort in the whole dataset. For both measurements, the correlation was stronger at lower levels of PEEP. The difference in the diaphragm thickening fraction during tidal breathing between PEEP 15 and PEEP 0 was negatively related to the change in the functional residual capacity and the change in alveolar dead space. Conclusions: Different levels of PEEP significantly modified the diaphragmatic thickness and thickening fraction, showing a PEEP-induced decrease in the diaphragm contractile efficiency. When using ultrasound to assess diaphragm size and function, the potential effect of lung inflation should be taken into account.

Role of acupuncture in critically ill patients: A systematic review.

Acupuncture is part of a complex medical approach used in China for about 2000 years, known as Traditional Chinese Medicine, whose central assumption is that health occurs when the patterned energy flow throughout the body is balanced. Within this paradigm, acute illness occurs when a major state of imbalance or disruption arises, and the use of acupuncture may help in correcting these imbalances. While the Chinese hospital system often offers the integration of traditional and western medicine, in Europe and the United States this combined approach is infrequently practiced. However, several investigations have consistently shown the effectiveness of acupuncture for different aspects of critical illness. The aim of this systematic review is to increase the clinician's awareness of the current evidence regarding the use of acupuncture for the management of critically ill patients, both alone or as a complement to western medicine. The effects of acupuncture on critical illness, with a particular focus on respiratory function, pain and delirium treatment and prevention, circulatory function, nutritional support, and recovery after acute illness are explored and summarized, and evidence is provided that acupuncture is an acceptable and feasible option for the management of several aspects of critical illness. In addition, we suggest a practical selection of potentially useful acupuncture points in the critical care setting, with indications for simple localization and the correct puncture method.

Ultrasonographic Features of Muscular Weakness and Muscle Wasting in Critically Ill Patients.

Muscle wasting begins as soon as in the first week of one's ICU stay and patients with multi-organ failure lose more muscle mass and suffer worse functional impairment as a consequence. Muscle wasting and weakness are mainly characterized by a generalized, bilateral lower limb weakness. However, the impairment of the respiratory and/or oropharyngeal muscles can also be observed with important consequences for one's ability to swallow and cough. Muscle wasting represents the result of the disequilibrium between breakdown and synthesis, with increased protein degradation relative to protein synthesis. It is worth noting that the resulting functional disability can last up to 5 years after discharge, and it has been estimated that up to 50% of patients are not able to return to work during the first year after ICU discharge. In recent years, ultrasound has played an increasing role in the evaluation of muscle. Indeed, ultrasound allows an objective evaluation of the cross-sectional area, the thickness of the muscle, and the echogenicity of the muscle. Furthermore, ultrasound can also estimate the thickening fraction of muscle. The objective of this review is to analyze the current understanding of the pathophysiology of acute skeletal muscle wasting and to describe the ultrasonographic features of normal muscle and muscle weakness.

Left Ventricular Diastolic Dysfunction in ARDS Patients.

BACKGROUND: The aim of this study was to evaluate the possible presence of diastolic dysfunction and its possible effects in terms of respiratory mechanics, gas exchange and lung recruitability in mechanically ventilated ARDS. METHODS: Consecutive patients admitted in intensive care unit (ICU) with ARDS were enrolled. Echocardiographic evaluation was acquired at clinical PEEP level. Lung CT-scan was performed at 5 and 45 cmH2O. In the study, 2 levels of PEEP (5 and 15 cmH2O) were randomly applied. RESULTS: A total of 30 patients were enrolled with a mean PaO2/FiO2 and a median PEEP of 137 ± 52 and 10 [9-10] cmH2O, respectively. Of those, 9 patients (30%) had a diastolic dysfunction of grade 1, 2 and 3 in 33%, 45% and 22%, respectively, without any difference in gas exchange and respiratory mechanics. The total lung weight was significantly higher in patients with diastolic dysfunction (1669 [1354-1909] versus 1554 [1146-1942] g) but the lung recruitability was similar between groups (33.3 [27.3-41.4] versus 30.6 [20.0-38.8] %). Left ventricular ejection fraction (57 [39-62] versus 60 [57-60]%) and TAPSE (20.0 [17.0-24.0] versus 24.0 [20.0-27.0] mL) were similar between the two groups. The response to changes of PEEP from 5 to 15 cmH2O in terms of oxygenation and respiratory mechanics was not affected by the presence of diastolic dysfunction. CONCLUSIONS: ARDS patients with left ventricular diastolic dysfunction presented a higher amount of lung edema and worse outcome.

Violence and unsafety in Italian hospitals: Experience and perceptions of nursing students.

BACKGROUND: Assessment of workplace violence towards healthcare workers represents a challenge for healthcare organizations worldwide. Workers' experience and perceived risk of violence may have a serious impact on job satisfaction and retention of workers. To date, no studies have been conducted on nursing students. OBJECTIVES: To assess the prevalence of physical and non-physical violence among nursing students during their clinical experiences and to analyze the perceived risk of violence. METHODS: Multicentre, cross-sectional survey. We enrolled a convenience sample of nursing students of the bachelor's degree in Nursing of the University of Milan (Italy). The students completed a structured questionnaire prepared in accordance with the available literature on violence in healthcare settings. RESULTS: Out of 1185 questionnaires sent, 603 were collected (50.89%). 35.1% had experience of verbal violence during the clinical internship training period, while 8.1% were victims of physical violence. 202 students (33.5%) reported unsafety, which was related to experience of physical or psychological violence, witnessed episodes of violence, gender, hospital structure and efficacy of the safety policies. CONCLUSIONS: Our findings highlight that nursing students are exposed to the risk of violence which influences their perception of risk.

Effect of Acupuncture on Diaphragm Function in Healthy Volunteers: A Pilot Clinical Study.

Introduction: In western medicine, the diaphragm is the main inspiratory muscle. It is involved in the postural control of the trunk and contributes to balance performance. In traditional Chinese medicine (TCM), the diaphragm represents a gateway between the lower and upper parts of the body, and it regulates the descending and ascending functions of the whole organism. The aim of this study was to assess the effect of acupuncture on diaphragm function. Methods: A proof-of-concept, prospective, controlled, pilot trial in healthy volunteers. Respiratory rate, inspired volume, diaphragm excursion, and thickening were measured during tidal and maximal breathing at baseline and after sham or real acupuncture. Acupuncture was performed on Yanglingquan (GB34), Tai Chong (LV3), Danzhong (CV17), Geshu (BL17), and Geguan (BL46). Results: Ten participants were enrolled (6 males, weight 71 ± 12 kg, height 173 ± 9 cm, BMI 21 ± 1.3 kg/m2). During tidal breathing, tidal volume, diaphragm displacement, and end-expiratory diaphragm thickness did not change with sham or real acupuncture as compared to baseline; thickening ratio was 43.5 ± 16.6 vs. 31.3 ± 14.9 (sham) vs. 30.8 ± 15.3% (baseline), p=0.1066. During breaths at vital capacity, the acupuncture group, as compared to both baseline and sham acupuncture, had a trend toward a larger tidal volume (3840 ± 690 vs. 3110 ± 880 vs. 3230 ± 750 ml, p=0.1247) and showed a significantly higher thickening ratio (270.6 ± 136.4 vs. 172.4 ± 57.4 vs. 188.6 ± 41.7%, p=0.0414). Conclusions: Acupuncture significantly influenced diaphragm function in healthy volunteers, improving its inspiratory thickening fraction during breaths at vital capacity, as compared to no or sham acupuncture.

Alarm fatigue in nurses working in intensive care units: A multicenter study.

BACKGROUND: Technological progress improves health care efficiency, quality, safety, and cost, supporting clinical activity in various scenarios, such as Intensive Care Unit (ICU). A timely response to alarms from monitors and other ICU electromedical devices is therefore crucial. The number of false alarms tend to desensitize care providers increasing the risk of experiencing alarm fatigue and, at times, lead to severe consequences for patients. OBJECTIVES: To assess the psychometric properties of the Italian version of the Alarm Fatigue Questionnaire and to explore the phenomenon of alarm fatigue among nurses working in intensive care settings. METHODS: The CVI-I was calculated to evaluate the validity of the content of the tool. Construct validity was investigated through exploratory factor analysis. Cronbach's alpha coefficient (α) was used to examine the internal consistency of the scale and Spearman's rho coefficient to test for stability.We designed a multicentre cross-sectional survey. A convenience sample of nurses from 4 Major Italian hospitals was recruited. The nurses completed the Italian version of the Alarm Fatigue Questionnaire. RESULTS: The content validity index CVI-S of the scale (CVI-S) was 91.11%; Cronbach's alpha coefficient was 0.71. The Italian version of the tool explained 67.18%of the overall variance. 396 nurses were enrolled (79.84%). The overall level of alarm fatigue was Me = 29 [22;30]. 42.17%of the sample reported prior experience with alarm fatigue incidents. CONCLUSIONS: The extension of alarm fatigue requires the adoption of a preventive intervention plan. The Italian version of the Alarm Fatigue Questionnaire shows promising psychometric properties.

EXpert consensus On Diaphragm UltraSonography in the critically ill (EXODUS): a Delphi consensus statement on the measurement of diaphragm ultrasound-derived parameters in a critical care setting.

BACKGROUND: Diaphragm ultrasonography is rapidly evolving in both critical care and research. Nevertheless, methodologically robust guidelines on its methodology and acquiring expertise do not, or only partially, exist. Therefore, we set out to provide consensus-based statements towards a universal measurement protocol for diaphragm ultrasonography and establish key areas for research. METHODS: To formulate a robust expert consensus statement, between November 2020 and May 2021, a two-round, anonymous and online survey-based Delphi study among experts in the field was performed. Based on the literature review, the following domains were chosen: "Anatomy and physiology", "Transducer Settings", "Ventilator Impact", "Learning and expertise", "Daily practice" and "Future directions". Agreement of ≥ 68% (≥ 10 panelists) was needed to reach consensus on a question. RESULTS: Of 18 panelists invited, 14 agreed to participate in the survey. After two rounds, the survey included 117 questions of which 42 questions were designed to collect arguments and opinions and 75 questions aimed at reaching consensus. Of these, 46 (61%) consensus was reached. In both rounds, the response rate was 100%. Among others, there was agreement on measuring thickness between the pleura and peritoneum, using > 10% decrease in thickness as cut-off for atrophy and using 40 examinations as minimum training to use diaphragm ultrasonography in clinical practice. In addition, key areas for research were established. CONCLUSION: This expert consensus statement presents the first set of consensus-based statements on diaphragm ultrasonography methodology. They serve to ensure high-quality and homogenous measurements in daily clinical practice and in research. In addition, important gaps in current knowledge and thereby key areas for research are established. Trial registration The study was pre-registered on the Open Science Framework with registration digital object identifier https://doi.org/10.17605/OSF.IO/HM8UG .

Time course of the Bioelectrical Impedance Vector Analysis and muscular ultrasound in critically ill patients.

PURPOSE: Several different tools have been developed to integrate the clinical and biochemical nutritional evaluations in critical care patients. Aims of this study were to evaluate the changes in the Bioelectrical Impedance Vector Analysis (BIVA) and ultrasonographic features of the diaphragm (DTee) and rectus femoris (RFCSA) during the first week of ICU stay. MATERIALS AND METHODS: Ninety-six adult mechanically ventilated patients enrolled within 24 h after the admission to the ICU (T1). RFCSA and diaphragm end-expiratory thickness were measured, as well as BIVA parameters. Anthropometric data and biochemical parameters were collected. The measurements were repeated on the 3rd (T3) and 7th (T7) days of ICU stay. RESULTS: During the study period, the phase angle significantly decreased by 21%, reactance by 27%, and resistance by 11%. Both RFCSA and DTee significantly decreased, while neither were correlated to any BIVA parameter. DTee was considerably higher in survivors vs. non-survivors. CONCLUSIONS: Body composition is significantly modified after one week of ICU stay. BIVA may be useful in the definition of hydration state, while it does not seem to track muscle mass. Different temporal trends of specific BIVA and muscle ultrasound parameters were found in patients with high or low severity of illness.

Positive end-expiratory pressure in COVID-19 acute respiratory distress syndrome: the heterogeneous effects.

BACKGROUND: We hypothesized that as CARDS may present different pathophysiological features than classic ARDS, the application of high levels of end-expiratory pressure is questionable. Our first aim was to investigate the effects of 5-15 cmH2O of PEEP on partitioned respiratory mechanics, gas exchange and dead space; secondly, we investigated whether respiratory system compliance and severity of hypoxemia could affect the response to PEEP on partitioned respiratory mechanics, gas exchange and dead space, dividing the population according to the median value of respiratory system compliance and oxygenation. Thirdly, we explored the effects of an additional PEEP selected according to the Empirical PEEP-FiO2 table of the EPVent-2 study on partitioned respiratory mechanics and gas exchange in a subgroup of patients. METHODS: Sixty-one paralyzed mechanically ventilated patients with a confirmed diagnosis of SARS-CoV-2 were enrolled (age 60 [54-67] years, PaO2/FiO2 113 [79-158] mmHg and PEEP 10 [10-10] cmH2O). Keeping constant tidal volume, respiratory rate and oxygen fraction, two PEEP levels (5 and 15 cmH2O) were selected. In a subgroup of patients an additional PEEP level was applied according to an Empirical PEEP-FiO2 table (empirical PEEP). At each PEEP level gas exchange, partitioned lung mechanics and hemodynamic were collected. RESULTS: At 15 cmH2O of PEEP the lung elastance, lung stress and mechanical power were higher compared to 5 cmH2O. The PaO2/FiO2, arterial carbon dioxide and ventilatory ratio increased at 15 cmH2O of PEEP. The arterial-venous oxygen difference and central venous saturation were higher at 15 cmH2O of PEEP. Both the mechanics and gas exchange variables significantly increased although with high heterogeneity. By increasing the PEEP from 5 to 15 cmH2O, the changes in partitioned respiratory mechanics and mechanical power were not related to hypoxemia or respiratory compliance. The empirical PEEP was 18 ± 1 cmH2O. The empirical PEEP significantly increased the PaO2/FiO2 but also driving pressure, lung elastance, lung stress and mechanical power compared to 15 cmH2O of PEEP. CONCLUSIONS: In COVID-19 ARDS during the early phase the effects of raising PEEP are highly variable and cannot easily be predicted by respiratory system characteristics, because of the heterogeneity of the disease.

Effects on Lung Gas Volume, Respiratory Mechanics and Gas Exchange of a Closed-Circuit Suctioning System during Volume- and Pressure-Controlled Ventilation in ARDS Patients.

Mechanically ventilated patients periodically require endotracheal suctioning. There are conflicting data regarding the loss of lung gas volume caused by the application of a negative pressure by closed-circuit suctioning. The aim of this study was to evaluate the effects of suctioning performed by a closed-circuit system in ARDS patients during volume- or pressure-controlled ventilation. In this prospective crossover-design study, 18 ARDS patients were ventilated under volume and pressure control applied in random order. Gas exchange, respiratory mechanics and EIT-derived end-expiratory lung volume (EELV) before the suctioning manoeuvre and after 5, 15 and 30 min were recorded. The tidal volume and respiratory rate were similar in both ventilation modes; in volume control, the EELV decreased by 31 ± 23 mL, 5 min after the suctioning, but it remained similar after 15 and 30 min; the oxygenation, PaCO2 and respiratory system elastance did not change. In the pressure control, 5 min after suctioning, EELV decreased by 35 (26-46) mL, the PaO2/FiO2 did not change, while PaCO2 increased by 5 and 30 min after suctioning (45 (40-51) vs. 48 (43-52) and 47 (42-54) mmHg, respectively). Our results suggest minimal clinical advantages when a closed system is used in volume-controlled compared to pressure-controlled ventilation.

Effect of Different Corticosteroid Regimens on the Outcome of Severe COVID-19-Related Acute Respiratory Failure. A Retrospective Analysis.

BACKGROUND: Systemic corticosteroids are associated with reduced mortality in COVID-19-related acute respiratory failure; however, the type and dose has not yet been established. OBJECTIVES: To compare the outcomes of dexamethasone vs. methylprednisolone, along with the effects of rescue, short-term, high-dose boluses of corticosteroids. METHODS: Before/after and case/control retrospective analysis of consecutive critically ill COVID-19 subjects. Subjects were initially given dexamethasone; however, after review of the local protocol, methylprednisolone was suggested. A three-day course of 1000 mg/day of methylprednisolone was administered in the case of refractory hypoxemia within the first 10 days of treatment. Propensity score-adjusted comparisons were performed. RESULTS: A total of 81 consecutive subjects were included (85% males, 60 ± 10 years, SAPS II 27 ± 7, SOFA 4 [IQR 3, 6] points) and 51 of these subjects (62.9%) received dexamethasone and 29 (35.8%) had methylprednisolone. The groups were well matched for age, comorbidities, and severity at admission. No differences were found in the duration of ICU stay, hospital mortality, or infectious complications between the groups. A total of 22 subjects (27.2%) received a rescue bolus; these subjects had a significantly lower oxygenation, a higher driving pressure, and an increased ventilatory ratio during the first ten days. Short-term/high-dose boluses were associated with higher hospital mortality, longer mechanical ventilation and ICU and hospital stay, and more infectious complications. A subgroup of subjects who received the boluses had significantly improved oxygenation and lower hospital mortality. CONCLUSIONS: We were unable to find any difference between dexamethasone or methylprednisolone on the explored outcomes; high-dose boluses of corticosteroids were associated with a worse outcome. However, a subgroup of subjects was identified in whom the high-dose boluses seemed beneficial.