Transpulmonary thermodilution

PURPOSE OF REVIEW

The purpose of this article is to systematically review and critically assess the existing data regarding the use of transpulmonary thermodilution (TPTD), by providing a detailed description of technical aspects of TPTD techniques, appraising the use of TPTD-derived parameters in specific clinical settings, and exploring the limits of this technique.

RECENT FINDINGS

The aim of hemodynamic monitoring is to optimize cardiac output (CO) and therefore improve oxygen delivery to the tissues. Hemodynamic monitoring plays a fundamental role in the management of acutely ill patients. TPTD is a reliable, multiparametric, advanced cardiopulmonary monitoring technique providing not only hemodynamic parameters related to cardiac function, but also to the redistribution of the extravascular water in the thorax. The hemodynamic monitors available in the market usually couple the intermittent measurement of the CO by TPTD with the arterial pulse contour analysis, offering automatic calibration of continuous CO and an accurate assessment of cardiac preload and fluid responsiveness.

SUMMARY

The TPTD is an invasive but well tolerated, multiparametric, advanced cardiopulmonary monitoring technique, allowing a comprehensive assessment of cardiopulmonary condition. Beyond the CO estimation, TPTD provides several indices that help answering questions that clinicians ask themselves during hemodynamic management. TPTD-guided algorithm obtained by pulse contour analysis may be useful to optimize fluid resuscitation by titrating fluid therapy according to functional hemodynamic monitoring and to define safety criteria to avoid fluid overload by following the changes in the extravascular lung water (EVLW) and pulmonary vascular permeability index (PVPI).

Effect of Angiotensin-Converting Enzyme Inhibitor and Angiotensin Receptor Blocker Initiation on Organ Support-Free Days in Patients Hospitalized With COVID-19: A Randomized Clinical Trial

IMPORTANCE

Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.

Objective

To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.

DESIGN, SETTING, AND PARTICIPANTS

In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non-critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).

INTERVENTIONS

Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days.

MAIN OUTCOMES AND MEASURES

The primary outcome was organ support-free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.

RESULTS

On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support-free days among critically ill patients was 10 (-1 to 16) in the ACE inhibitor group (n = 231), 8 (-1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support-free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).

CONCLUSIONS AND RELEVANCE

In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02735707.

Right Ventricle Response to Major Lung Resection (the RIVER Study)

Backgrounds

Major lung resection is associated with high postoperative morbidity and mortality, especially due to cardiorespiratory complications. Right ventricle (RV) ejection, pulmonary artery (PA) pressure, and tone are tightly coupled. Since the RV is exquisitely sensitive to changes in afterload, an acute increase in RV outflow resistance (i.e., acute pulmonary embolism [PE]) will cause acute RV dilatation and, a reduction of left ventricle compliance too, rapidly spiraling to acute cardiogenic shock and death. We investigated the changing in RV performance after major lung resection.

Materials and Methods

We carried out transthoracic echocardiography (TTE) aiming at searching for the incidence of early RV systolic dysfunction (defined as tricuspid annulus plane systolic excursion [TAPSE] <17 cm, S'-tissue Doppler imaging <10 cm/s) and estimate the RV-PA coupling by the TAPSE/pulmonary artery pressures (PAPs) ratio after major lung resection. The TTE has been performed before and immediately after surgery.

Results

After the end of the operation the echocardiographic parameters of the RV function worsened. TAPSE decreased from 24 (21 ÷ 28) to 18 (16 ÷ 22) mm (P = 0.015) and PAPs increased from 26 (25 ÷ 30) to 30 (25 ÷ 39) mmHg (P = 0.013). TAPSE/PAPs ratio decreased from 0.85 (0.80 ÷ 0.90) to 0.64 (0.54 ÷ 0.79) mm/mmHg (P = 0.002).

Conclusions

In line with previous reports, after major lung resection the increase in afterload reduces the RV function, but the impairment remains clinically not relevant. The different clinical picture of an acute cor pulmonale due to PE implies that the pathogenesis of cardiac failure involves more pathways than the mere mechanic occlusion of the blood flow.

Bioengineering and medical informatics education in MD programs: perspectives from three Italian experiences

BACKGROUND

Given the impact of bioengineering and medical informatics technologies in health care, the design and implementation of education programs able to combine medical curricula with a proper teaching on engineering and informatics is now of paramount importance. In Italy, this goal has to fit in with the existing higher education system, which is structured into Bachelor programs and Master programs. Medicine and Surgery programs, instead, are designed as a six-year single-cycle Degree Program in Medicine and Surgery which comprises both class attendance and hospital internship and training. This program allows students to become Medical Doctors (MD). The different organization of this University program makes it not easy to introduce further contents, namely hard science courses, in the educational program. Notwithstanding this, we present here some recent innovative programs aimed at widening MD curriculum by including biomedical engineering and informatics subjects. In particular, we will introduce three of them. Two are joint-degree programs, the first between Humanitas University and Politecnico di Milano (MEDTEC School), and the second between University of Calabria and University Magna Graecia of Catanzaro (Medicina e Chirurgia TD). The Third one is a Professional Master coupled with an MD degree, based on a joint program among Pavia University, Pisa University, the Institute of Advanced studies in Pavia and the Scuola Superiore S. Anna in Pisa (MEET).

CONTRIBUTION

The paper provides a description of the fundamental design principles of the three above mentioned programs, and explores some aspects of the teaching modules, highlighting their positive aspects. In particular, we show how the three different programs allow students to enrich their knowledge by studying engineering subjects and innovative methods and technologies, as well as their applications to patient care.

CONCLUSIONS

The MEDTEC program is the first degree program at Italian and international scale which integrates medical and engineering subjects. In the following years, other programs were issued in Italy, defining similar education programs to couple a degree in medicine education with bioengineering and medical informatics, among which Medicina e Chirurgia TD and MEET. We believe the experiences described here in this paper represent the possibility of bridging the gap between medical and technological competencies.

Variation in Communication and Family Visiting Policies in Italian Intensive Care Units during the COVID-19 Pandemic: A Secondary Analysis of the COVISIT International Survey

BACKGROUND

During COVID-19 pandemic, restrictions to in-person visiting of caregivers to patients admitted to intensive care units (ICU) were applied in many countries. Our aim was to describe the variations in communication and family visiting policies in Italian ICUs during the pandemic.

METHODS

A secondary analysis from the COVISIT international survey was conducted, focusing on data from Italy.

RESULTS

Italian ICUs provided 118 (18%) responses out of 667 responses collected worldwide. A total of 12 Italian ICUs were at the peak of COVID-19 admissions at the time of the survey and 42/118 had 90% or more of patients admitted to ICU affected by COVID-19. During the COVID-19 peak, 74% of Italian ICUs adopted a no-in-person-visiting policy. This remained the most common strategy (67%) at the time of the survey. Information to families was provided by regular phone calls (81% in Italy versus 47% for the rest of the world). Virtual visiting was available for 69% and most commonly performed using devices provided by the ICU (71% in Italy versus 36% outside Italy).

CONCLUSION

Our study showed that restrictions to the ICU applied during the COVID-19 pandemic were still in use at the time of the survey. The main means of communication with caregivers were telephone and virtual meetings.

Relationship between intraventricular mechanical dyssynchrony and left ventricular systolic and diastolic performance: An in vivo experimental study

Left ventricular mechanical dyssynchrony (LVMD) refers to the nonuniformity in mechanical contraction and relaxation timing in different ventricular segments. We aimed to determine the relationship between LVMD and LV performance, as assessed by ventriculo-arterial coupling (VAC), LV mechanical efficiency (LV_eff ), left ventricular ejection fraction (LVEF), and diastolic function during sequential experimental changes in loading and contractile conditions. Thirteen Yorkshire pigs submitted to three consecutive stages with two opposite interventions each: changes in afterload (phenylephrine/nitroprusside), preload (bleeding/reinfusion and fluid bolus), and contractility (esmolol/dobutamine). LV pressure-volume data were obtained with a conductance catheter. Segmental mechanical dyssynchrony was assessed by global, systolic, and diastolic dyssynchrony (DYS) and internal flow fraction (IFF). Late systolic LVMD was related to an impaired VAC, LV_eff , and LVEF, whereas diastolic LVMD was associated with delayed LV relaxation (logistic tau), decreased LV peak filling rate, and increased atrial contribution to LV filling. The hemodynamic factors related to LVMD were contractility, afterload, and heart rate. However, the relationship between these factors differed throughout the cardiac cycle. LVMD plays a significant role in LV systolic and diastolic performance and is associated with hemodynamic factors and intraventricular conduction.

Early Hospital Discharge on Day Two Post Robotic Lobectomy with Telehealth Home Monitoring: A Pilot Study

Despite the adoption of enhanced recovery programs, the reported postoperative length of stay after robotic surgery is 4 days even in highly specialized centers. We report preliminary results of a pilot study for a new protocol of early discharge (on day 2) with telehealth home monitoring after robotic lobectomy for lung cancer. All patients with a caregiver were discharged on postoperative day 2 with a telemonitoring device if they satisfied specific discharge criteria. Teleconsultations were scheduled once in the afternoon of post-operative day 2, twice on postoperative day 3, and then once a day until the chest tube removal. Post-discharge vital signs were recorded by patients at least four times daily through the device and were available for consultation by two surgeons through phone application. In case of sudden variation of vital signs or occurrence of adverse events, a direct telephone line was available for patients as well as a protected re-hospitalization path. Primary outcome was the safety evaluated by the occurrence of post-discharge complications and readmissions. Secondary outcome was the evaluation of resources optimization (hospitalization days) maintaining the standard of care. During the study period, twelve patients satisfied all preoperative clinical criteria to be enrolled in our protocol. Two of twelve enrolled patients were successively excluded because they did not satisfy discharge criteria on postoperative day 2. During telehealth home monitoring a total of 27/427 vital-sign measurements violated the threshold in seven patients. Among the threshold violations, only 1 out of 27 was a critical violation and was managed at home. No postoperative complication occurred neither readmission was needed. A mean number of three hospitalization days was avoided and an estimated economic benefit of about EUR 500 for a single patient was obtained if compared with patients submitted to VATS lobectomy in the same period. These preliminary results confirm that adoption of telemonitoring allows, in selected patients, a safe discharge on postoperative day 2 after robotic surgery for early-stage NSCLC. A potential economic benefit could derive from this protocol if this data will be confirmed in larger sample.

Wearable Health Technology for Preoperative Risk Assessment in Elderly Patients: The WELCOME Study

Preoperative identification of high-risk groups has been extensively studied to improve patients' outcomes. Wearable devices, which can track heart rate and physical activity data, are starting to be evaluated for patients' management. We hypothesized that commercial wearable devices (WD) may provide data associated with preoperative evaluation scales and tests, to identify patients with poor functional capacity at increased risk for complications. We conducted a prospective observational study including seventy-year-old patients undergoing two-hour surgeries under general anesthesia. Patients were asked to wear a WD for 7 days before surgery. WD data were compared to preoperatory clinical evaluation scales and with a 6-min walking test (6MWT). We enrolled 31 patients, with a mean age of 76.1 (SD ± 4.9) years. There were 11 (35%) ASA 3-4 patients. 6MWT results averaged 328.9 (SD ± 99.5) m. Daily steps and 𝑉𝑂2𝑚𝑎𝑥 as recorded using WD and were associated with 6MWT performance (R = 0.56, p = 0.001 and r = 0.58, p = 0.006, respectively) and clinical evaluation scales. This is the first study to evaluate WD as preoperative evaluation tools; we found a strong association between 6MWT, preoperative scales, and WD data. Low-cost wearable devices are a promising tool for the evaluation of cardiopulmonary fitness. Further research is needed to validate WD in this setting.

REVersal of nEuromusculAr bLocking Agents in Patients Undergoing General Anaesthesia (REVEAL Study)

Background: Neuromuscular blocking agent (NMBA) monitoring and reversals are key to avoiding residual curarization and improving patient outcomes. Sugammadex is a NMBA reversal with favorable pharmacological properties. There is a lack of real-world data detailing how the diffusion of sugammadex affects anesthetic monitoring and practice. Methods: We conducted an electronic health record analysis study, including all adult surgical patients undergoing general anesthesia with orotracheal intubation, from January 2016 to December 2019, to describe changes and temporal trends of NMBAs and NMBA reversals administration. Results: From an initial population of 115,046 surgeries, we included 37,882 procedures, with 24,583 (64.9%) treated with spontaneous recovery from neuromuscular block and 13,299 (35.1%) with NMBA reversals. NMBA reversals use doubled over 4 years from 25.5% to 42.5%, mainly driven by sugammadex use, which increased from 17.8% to 38.3%. Rocuronium increased from 58.6% (2016) to 94.5% (2019). Factors associated with NMBA reversal use in the multivariable analysis were severe obesity (OR 3.33 for class II and OR 11.4 for class III obesity, p-value < 0.001), and high ASA score (OR 1.47 for ASA III). Among comorbidities, OSAS, asthma, and other respiratory diseases showed the strongest association with NMBA reversal administration. Conclusions: Unrestricted availability of sugammadex led to a considerable increase in pharmacological NMBA reversal, with rocuronium use also rising. More research is needed to determine how unrestricted and safer NMBA reversal affects anesthesia intraoperative monitoring and practice.

Trans-Esophageal Echocardiography of the Descending Aorta and Celiac Trunk as an Intraoperative Monitoring for Median Arcuate Ligament Syndrome (MALS) Treatment: Technique Proposal and Two Case Reports

Dunbar syndrome is caused by the compression of the celiac artery by the median arcuate ligament (MAL) and the diaphragmatic crura, presenting with abdominal pain. The treatment is surgical, with the aim of dissecting and separating the diaphragmatic crura from the celiac axis, restoring blood flow in the celiac trunk. We propose the use of transesophageal echocardiography to measure the peak systolic velocity in the celiac trunk and to evaluate, in real time, the efficacy of the surgery during MAL resection. Two clinical cases with practical implications are reported. In one of these, the ultrasound exam was useful in providing an intraoperative confirmation of the outcome of the resection.

A plea for personalization of the hemodynamic management of septic shock

Although guidelines provide excellent expert guidance for managing patients with septic shock, they leave room for personalization according to patients' condition. Hemodynamic monitoring depends on the evolution phase: salvage, optimization, stabilization, and de-escalation. Initially during the salvage phase, monitoring to identify shock etiology and severity should include arterial pressure and lactate measurements together with clinical examination, particularly skin mottling and capillary refill time. Low diastolic blood pressure may trigger vasopressor initiation. At this stage, echocardiography may be useful to identify significant cardiac dysfunction. During the optimization phase, echocardiographic monitoring should be pursued and completed by the assessment of tissue perfusion through central or mixed-venous oxygen saturation, lactate, and carbon dioxide veno-arterial gradient. Transpulmonary thermodilution and the pulmonary artery catheter should be considered in the most severe patients. Fluid therapy also depends on shock phases. While administered liberally during the resuscitation phase, fluid responsiveness should be assessed during the optimization phase. During stabilization, fluid infusion should be minimized. In the de-escalation phase, safe fluid withdrawal could be achieved by ensuring tissue perfusion is preserved. Norepinephrine is recommended as first-line vasopressor therapy, while vasopressin may be preferred in some patients. Essential questions remain regarding optimal vasopressor selection, combination therapy, and the most effective and safest escalation. Serum renin and the angiotensin I/II ratio may identify patients who benefit most from angiotensin II. The optimal therapeutic strategy for shock requiring high-dose vasopressors is scant. In all cases, vasopressor therapy should be individualized, based on clinical evaluation and blood flow measurements to avoid excessive vasoconstriction. Inotropes should be considered in patients with decreased cardiac contractility associated with impaired tissue perfusion. Based on pharmacologic properties, we suggest as the first test a limited dose of dobutamine, to add enoximone or milrinone in the second line and substitute or add levosimendan if inefficient. Regarding adjunctive therapies, while hydrocortisone is nowadays advised in patients receiving high doses of vasopressors, patients responding to corticosteroids may be identified in the future by the analysis of selected cytokines or specific transcriptomic endotypes. To conclude, although some general rules apply for shock management, a personalized approach should be considered for hemodynamic monitoring and support.

Fluid challenge in critically ill patients receiving haemodynamic monitoring: a systematic review and comparison of two decades

Introduction

Fluid challenges are widely adopted in critically ill patients to reverse haemodynamic instability. We reviewed the literature to appraise fluid challenge characteristics in intensive care unit (ICU) patients receiving haemodynamic monitoring and considered two decades: 2000–2010 and 2011–2021.

Methods

We assessed research studies and collected data regarding study setting, patient population, fluid challenge characteristics, and monitoring. MEDLINE, Embase, and Cochrane search engines were used. A fluid challenge was defined as an infusion of a definite quantity of fluid (expressed as a volume in mL or ml/kg) in a fixed time (expressed in minutes), whose outcome was defined as a change in predefined haemodynamic variables above a predetermined threshold.

Results

We included 124 studies, 32 (25.8%) published in 2000–2010 and 92 (74.2%) in 2011–2021, overall enrolling 6,086 patients, who presented sepsis/septic shock in 50.6% of cases. The fluid challenge usually consisted of 500 mL (76.6%) of crystalloids (56.6%) infused with a rate of 25 mL/min. Fluid responsiveness was usually defined by a cardiac output/index (CO/CI) increase ≥ 15% (70.9%). The infusion time was quicker (15 min vs 30 min), and crystalloids were more frequent in the 2011–2021 compared to the 2000–2010 period.

Conclusions

In the literature, fluid challenges are usually performed by infusing 500 mL of crystalloids bolus in less than 20 min. A positive fluid challenge response, reported in 52% of ICU patients, is generally defined by a CO/CI increase ≥ 15%. Compared to the 2000–2010 decade, in 2011–2021 the infusion time of the fluid challenge was shorter, and crystalloids were more frequently used.

Pathophysiology of fluid administration in critically ill patients

Fluid administration is a cornerstone of treatment of critically ill patients. The aim of this review is to reappraise the pathophysiology of fluid therapy, considering the mechanisms related to the interplay of flow and pressure variables, the systemic response to the shock syndrome, the effects of different types of fluids administered and the concept of preload dependency responsiveness. In this context, the relationship between preload, stroke volume (SV) and fluid administration is that the volume infused has to be large enough to increase the driving pressure for venous return, and that the resulting increase in end-diastolic volume produces an increase in SV only if both ventricles are operating on the steep part of the curve. As a consequence, fluids should be given as drugs and, accordingly, the dose and the rate of administration impact on the final outcome. Titrating fluid therapy in terms of overall volume infused but also considering the type of fluid used is a key component of fluid resuscitation. A single, reliable, and feasible physiological or biochemical parameter to define the balance between the changes in SV and oxygen delivery (i.e., coupling “macro” and “micro” circulation) is still not available, making the diagnosis of acute circulatory dysfunction primarily clinical.

Fluids are drugs used in patients with shock to increase the cardiac output with the aim to improve oxygen delivery to the cells. The response to fluid administration is determined by the physiological interaction of cardiac function and venous return. In septic shock, the beneficial clinical response of fluid administration is rapidly reduced after few hours and fluid titration is crucial to avoid detrimental fluid overload. The fluid challenge is a fluid bolus given at a defined quantity and rate to assess fluid responsiveness.

The ideal fluid for critically ill patients does not exist; however, crystalloids should be used as first choice. Balanced crystalloid solutions may be associated with better outcomes but the evidence is still low. Albumin infusion may have a role in already fluid resuscitated patients at risk of fluid overload.

Fluid administration is integrated into the complex management of pressure and flow “macro” hemodynamic variables, coupled to the “micro” local tissue flow distribution and regional metabolism. Macro-variables are managed by measuring systemic blood pressure and evaluating the global cardiac function. The critical threshold of oxygen delivery to the cells is difficult to estimate, however, several indexes and clinical signs may be considered as surrogate of that, and integrated in a decision-making process at the bedside.

The Cardiac Power Index during Abdominal Open Aortic Surgery: Intraoperative Insights into the Cardiac Performance-A Retrospective Observational Analysis

Background: The Cardiac Power Index (CPI) measures the rate of energy output generated by the heart and correlates this with in-hospital mortality due to cardiogenic shock. In open aortic surgery, both aortic clamping and unclamping expose the heart to abrupt variations of the left ventricle afterload, preload, and contractility, with possible hemodynamic impairment. We investigated how aortic-cross clamping (Ao-XC) and unclamping (Ao-UC) procedures affect the CPI during open aortic surgery. Methods: We retrospectively analyzed our surgical database of 67 patients submitted to open surgical aortic repair at Humanitas Research Hospital, Milan. Patients were monitored by an EV1000-FloTrac SystemTM (Edwards Lifescience, Irvine, CA, USA) beyond the standard intra-operative hemodynamic monitoring. The primary outcome was the variation of basal CPI after aortic clamping and unclamping. Secondary outcomes were variations of the cardiac index (CI), mean arterial pressure (MAP), heart rate, and lactate during aortic clamping and after unclamping. The CPI was computed as: (CI × MAP)/451. Results: The CPI changed significantly after aortic unclamping. CPI: basal = 0.39 ± 0.1 W/m2, after Ao-XC = 0.39 ± 0.1 W/m2, and after Ao-UC = 0.44 ± 0.2 W/m2, p < 0.05. The CI changed during both cross-clamping and unclamping (p < 0.0001), whilst the MAP and heart rate did not during any phase of the surgery. Five subjects (8.3%) needed inotropic support after cross-clamping. Their basal CPI was lower than the general population: 0.31 ± 0.11 W/m2 vs. 0.39 ± 0.1 W/m2. Conclusions: The CPI describes the adaptation of the cardiac function to the changes in preload, contractility, and afterload occurring during aortic cross-clamping and unclamping. It may be used to explore the cardiac performance in real-time and predict cardiac impairment in the intraoperative period in a minimally invasive way, similar to ventriculo-arterial coupling parameters.

Pressure response to fluid challenge administration in hypotensive surgical patients: a post-hoc pharmacodynamic analysis of five datasets

In this study we evaluated the effect of fluid challenge (FC) administration in elective surgical patients with low or normal blood pressure. Secondarily, we appraised the pharmacodynamic effect of FC in normotensive and hypotensive patients. We assessed five merged datasets of patients with a baseline mean arterial pressure (MAP) above or below 65 mmHg and assessed the changes of systolic, diastolic, mean and dicrotic arterial pressures, dynamic indexes of fluid responsiveness and arterial elastance over a 10-min infusion. The hemodynamic effect was assessed by considering the net area under the curve (AUC), the maximal percentage difference from baseline (d_max), the time when the maximal value was observed (t_max) and change from baseline at 5-min (d₅) after FC end. A stroke volume index increase > 10% with respect to the baseline value after FC administration indicated fluid response. Two hundred-seventeen patients were analysed [102 (47.0%) fluid responders]. On average, FC restored a MAP [Formula: see text] 65 mmHg after 5 min. The AUCs and the d_max of pressure variables and arterial elastance of hypotensive patients were all significantly greater than normotensive patients. Pressure variables and arterial elastance changes in the hypotensive group were all significantly higher at d₅ as compared to the normotensive group. In hypotensive patients, FC restores a MAP [Formula: see text] 65 mmHg after 5 min from infusion start. The hemodynamic profile of FC in hypotensive and normotensive patients is different; both the magnitude of pressure augmentation and duration is greater in the hypotensive group.

Association of COVID-19 Vaccinations With Intensive Care Unit Admissions and Outcome of Critically Ill Patients With COVID-19 Pneumonia in Lombardy, Italy

Importance

Data on the association of COVID-19 vaccination with intensive care unit (ICU) admission and outcomes of patients with SARS-CoV-2-related pneumonia are scarce.

Objective

To evaluate whether COVID-19 vaccination is associated with preventing ICU admission for COVID-19 pneumonia and to compare baseline characteristics and outcomes of vaccinated and unvaccinated patients admitted to an ICU.

Design, Setting, and Participants

This retrospective cohort study on regional data sets reports: (1) daily number of administered vaccines and (2) data of all consecutive patients admitted to an ICU in Lombardy, Italy, from August 1 to December 15, 2021 (Delta variant predominant). Vaccinated patients received either mRNA vaccines (BNT162b2 or mRNA-1273) or adenoviral vector vaccines (ChAdOx1-S or Ad26.COV2). Incident rate ratios (IRRs) were computed from August 1, 2021, to January 31, 2022; ICU and baseline characteristics and outcomes of vaccinated and unvaccinated patients admitted to an ICU were analyzed from August 1 to December 15, 2021.

Exposures

COVID-19 vaccination status (no vaccination, mRNA vaccine, adenoviral vector vaccine).

Main Outcomes and Measures

The incidence IRR of ICU admission was evaluated, comparing vaccinated people with unvaccinated, adjusted for age and sex. The baseline characteristics at ICU admission of vaccinated and unvaccinated patients were investigated. The association between vaccination status at ICU admission and mortality at ICU and hospital discharge were also studied, adjusting for possible confounders.

Results

Among the 10 107 674 inhabitants of Lombardy, Italy, at the time of this study, the median [IQR] age was 48 [28-64] years and 5 154 914 (51.0%) were female. Of the 7 863 417 individuals who were vaccinated (median [IQR] age: 53 [33-68] years; 4 010 343 [51.4%] female), 6 251 417 (79.5%) received an mRNA vaccine, 550 439 (7.0%) received an adenoviral vector vaccine, and 1 061 561 (13.5%) received a mix of vaccines and 4 497 875 (57.2%) were boosted. Compared with unvaccinated people, IRR of individuals who received an mRNA vaccine within 120 days from the last dose was 0.03 (95% CI, 0.03-0.04; P < .001), whereas IRR of individuals who received an adenoviral vector vaccine after 120 days was 0.21 (95% CI, 0.19-0.24; P < .001). There were 553 patients admitted to an ICU for COVID-19 pneumonia during the study period: 139 patients (25.1%) were vaccinated and 414 (74.9%) were unvaccinated. Compared with unvaccinated patients, vaccinated patients were older (median [IQR]: 72 [66-76] vs 60 [51-69] years; P < .001), primarily male individuals (110 patients [79.1%] vs 252 patients [60.9%]; P < .001), with more comorbidities (median [IQR]: 2 [1-3] vs 0 [0-1] comorbidities; P < .001) and had higher ratio of arterial partial pressure of oxygen (Pao2) and fraction of inspiratory oxygen (FiO2) at ICU admission (median [IQR]: 138 [100-180] vs 120 [90-158] mm Hg; P = .007). Factors associated with ICU and hospital mortality were higher age, premorbid heart disease, lower Pao2/FiO2 at ICU admission, and female sex (this factor only for ICU mortality). ICU and hospital mortality were similar between vaccinated and unvaccinated patients.

Conclusions and Relevance

In this cohort study, mRNA and adenoviral vector vaccines were associated with significantly lower risk of ICU admission for COVID-19 pneumonia. ICU and hospital mortality were not associated with vaccinated status. These findings suggest a substantial reduction of the risk of developing COVID-19-related severe acute respiratory failure requiring ICU admission among vaccinated people.

How can assessing hemodynamics help to assess volume status?

In critically ill patients, fluid infusion is aimed at increasing cardiac output and tissue perfusion. However, it may contribute to fluid overload which may be harmful. Thus, volume status, risks and potential efficacy of fluid administration and/or removal should be carefully evaluated, and monitoring techniques help for this purpose. Central venous pressure is a marker of right ventricular preload. Very low values indicate hypovolemia, while extremely high values suggest fluid harmfulness. The pulmonary artery catheter enables a comprehensive assessment of the hemodynamic profile and is particularly useful for indicating the risk of pulmonary oedema through the pulmonary artery occlusion pressure. Besides cardiac output and preload, transpulmonary thermodilution measures extravascular lung water, which reflects the extent of lung flooding and assesses the risk of fluid infusion. Echocardiography estimates the volume status through intravascular volumes and pressures. Finally, lung ultrasound estimates lung edema. Guided by these variables, the decision to infuse fluid should first consider specific triggers, such as signs of tissue hypoperfusion. Second, benefits and risks of fluid infusion should be weighted. Thereafter, fluid responsiveness should be assessed. Monitoring techniques help for this purpose, especially by providing real time and precise measurements of cardiac output. When decided, fluid resuscitation should be performed through fluid challenges, the effects of which should be assessed through critical endpoints including cardiac output. This comprehensive evaluation of the risk, benefits and efficacy of fluid infusion helps to individualize fluid management, which should be preferred over a fixed restrictive or liberal strategy.

Variation in communication and family visiting policies in intensive care within and between countries during the Covid-19 pandemic: The COVISIT international survey

BACKGROUND

During the COVID-19 pandemic, intensive care units (ICU) introduced restrictions to in-person family visiting to safeguard patients, healthcare personnel, and visitors.

METHODS

We conducted a web-based survey (March-July 2021) investigating ICU visiting practices before the pandemic, at peak COVID-19 ICU admissions, and at the time of survey response. We sought data on visiting policies and communication modes including use of virtual visiting (videoconferencing).

RESULTS

We obtained 667 valid responses representing ICUs in all continents. Before the pandemic, 20% (106/525) had unrestricted visiting hours; 6% (30/525) did not allow in-person visiting. At peak, 84% (558/667) did not allow in-person visiting for patients with COVID-19; 66% for patients without COVID-19. This proportion had decreased to 55% (369/667) at time of survey reporting. A government mandate to restrict hospital visiting was reported by 53% (354/646). Most ICUs (55%, 353/615) used regular telephone updates; 50% (306/667) used telephone for formal meetings and discussions regarding prognosis or end-of-life. Virtual visiting was available in 63% (418/667) at time of survey.

CONCLUSIONS

Highly restrictive visiting policies were introduced at the initial pandemic peaks, were subsequently liberalized, but without returning to pre-pandemic practices. Telephone became the primary communication mode in most ICUs, supplemented with virtual visits.

Effective hemodynamic monitoring

Hemodynamic monitoring is the centerpiece of patient monitoring in acute care settings. Its effectiveness in terms of improved patient outcomes is difficult to quantify. This review focused on effectiveness of monitoring-linked resuscitation strategies from: (1) process-specific monitoring that allows for non-specific prevention of new onset cardiovascular insufficiency (CVI) in perioperative care. Such goal-directed therapy is associated with decreased perioperative complications and length of stay in high-risk surgery patients. (2) Patient-specific personalized resuscitation approaches for CVI. These approaches including dynamic measures to define volume responsiveness and vasomotor tone, limiting less fluid administration and vasopressor duration, reduced length of care. (3) Hemodynamic monitoring to predict future CVI using machine learning approaches. These approaches presently focus on predicting hypotension. Future clinical trials assessing hemodynamic monitoring need to focus on process-specific monitoring based on modifying therapeutic interventions known to improve patient-centered outcomes.

Hemodynamic management of acute brain injury caused by cerebrovascular diseases: a survey of the European Society of Intensive Care Medicine

BACKGROUND

The optimal hemodynamic targets and management of patients with acute brain injury are not completely elucidated, but recent evidence points to important impact on clinical outcomes. We performed an international survey with the aim to investigate the practice in the hemodynamic targets, monitoring, and management of patients with acute ischemic stroke (AIS), intracranial hemorrhage (ICH) and subarachnoid hemorrhage (SAH).

METHODS

This survey was endorsed by the European Society of Intensive Care (ESICM). An electronic questionnaire of 76 questions divided in 4 sections (general information, AIS, ICH, SAH specific questions) was available between January 2022 to March 2022 on the ESICM website.

RESULTS

One hundred fifty-four healthcare professionals from 36 different countries and at least 98 different institutions answered the survey. Routine echocardiography is routinely performed in 37% of responders in AIS, 34% in ICH and 38% in SAH. Cardiac output monitoring is used in less than 20% of cases by most of the responders. Cardiovascular complications are the main reason for using advanced hemodynamic monitoring, and norepinephrine is the most common drug used to increase arterial blood pressure. Most responders target fluid balance to neutral (62% in AIS, 59% in ICH,44% in SAH), and normal saline is the most common fluid used. Large variability was observed regarding the blood pressure targets.

CONCLUSIONS

Hemodynamic management and treatment in patients with acute brain injury from cerebrovascular diseases vary largely in clinical practice. Further research is required to provide clear guidelines to physicians for the hemodynamic optimization of this group of patients.

Co-infection and ICU-acquired infection in COIVD-19 ICU patients: a secondary analysis of the UNITE-COVID data set

BACKGROUND

The COVID-19 pandemic presented major challenges for critical care facilities worldwide. Infections which develop alongside or subsequent to viral pneumonitis are a challenge under sporadic and pandemic conditions; however, data have suggested that patterns of these differ between COVID-19 and other viral pneumonitides. This secondary analysis aimed to explore patterns of co-infection and intensive care unit-acquired infections (ICU-AI) and the relationship to use of corticosteroids in a large, international cohort of critically ill COVID-19 patients.

METHODS

This is a multicenter, international, observational study, including adult patients with PCR-confirmed COVID-19 diagnosis admitted to ICUs at the peak of wave one of COVID-19 (February 15th to May 15th, 2020). Data collected included investigator-assessed co-infection at ICU admission, infection acquired in ICU, infection with multi-drug resistant organisms (MDRO) and antibiotic use. Frequencies were compared by Pearson's Chi-squared and continuous variables by Mann-Whitney U test. Propensity score matching for variables associated with ICU-acquired infection was undertaken using R library MatchIT using the "full" matching method.

RESULTS

Data were available from 4994 patients. Bacterial co-infection at admission was detected in 716 patients (14%), whilst 85% of patients received antibiotics at that stage. ICU-AI developed in 2715 (54%). The most common ICU-AI was bacterial pneumonia (44% of infections), whilst 9% of patients developed fungal pneumonia; 25% of infections involved MDRO. Patients developing infections in ICU had greater antimicrobial exposure than those without such infections. Incident density (ICU-AI per 1000 ICU days) was in considerable excess of reports from pre-pandemic surveillance. Corticosteroid use was heterogenous between ICUs. In univariate analysis, 58% of patients receiving corticosteroids and 43% of those not receiving steroids developed ICU-AI. Adjusting for potential confounders in the propensity-matched cohort, 71% of patients receiving corticosteroids developed ICU-AI vs 52% of those not receiving corticosteroids. Duration of corticosteroid therapy was also associated with development of ICU-AI and infection with an MDRO.

CONCLUSIONS

In patients with severe COVID-19 in the first wave, co-infection at admission to ICU was relatively rare but antibiotic use was in substantial excess to that indication. ICU-AI were common and were significantly associated with use of corticosteroids. Trial registration ClinicalTrials.gov: NCT04836065 (retrospectively registered April 8th 2021).