The role of ultrasonographic lung aeration score in the prediction of postoperative pulmonary complications: an observational study

Association of point-of-care lung ultrasound findings with 30-day pulmonary complications after cardiac surgery: A prospective cohort study

Background

Several studies have shown that bedside lung ultrasound findings in postanaesthesia care units (PACUs) and intensive care units (ICUs) correlate with postoperative pulmonary complications(PPCs) after noncardiac major surgery. However, it remains unclear whether lung ultrasound findings can be used as early predictors of PPCs in patients undergoing cardiac surgery. The main aim of our study was to evaluate the relationship between early postoperative point-of-care lung ultrasound findings and PPCs after cardiac surgery.

Methods

Two board-certified physicians performed a point-of-care pulmonary ultrasound on cardiac surgery patients approximately 2 h after the patient was admitted to the ICU. Pulmonary complications occurring within 30 days postoperatively were recorded. Logistic regression modeling was used to analyze the relationship between lung ultrasound findings and PPCs.

Results

PPCs occurred in 61 (30.9 %) of the 197 patients. Lung ultrasound scores(LUS), number of lung consolidation(NLC), and depth of pleural effusion(DPE) were more significant in patients who developed PPCs (P < 0.001). According to the multivariate analysis, NLC≥3(aOR 2.71,95%CI 1.14-6.44; p = 0.024)and DPE >0.95(aOR 3.79,95%CI 1.60-8.99; p = 0.002) were found to be independently associated with PPCs during this study.

Conclusions

Our study demonstrated that DPE >0.95 and NLC ≥3 were associated with PPCs after cardiac surgery based on bedside lung ultrasound findings in the ICU. When these signs manifest perioperatively, the surgeon should be alerted and the necessary steps should be taken, especially if they present simultaneously.

Adjustment of positive end-expiratory pressure to body mass index during mechanical ventilation in general anesthesia: BodyVent, a randomized controlled trial

BACKGROUND

In patients requiring general anesthesia, lung-protective ventilation can prevent postoperative pulmonary complications, which are associated with higher morbidity, mortality, and prolonged hospital stay. Application of positive end-expiratory pressure (PEEP) is one component of lung-protective ventilation. The correct strategy for setting adequate PEEP, however, remains controversial. PEEP settings that lead to a lower pressure difference between end-inspiratory plateau pressure and end-expiratory pressure ("driving pressure," ΔP) may reduce the risk of postoperative pulmonary complications. Preliminary data suggests that the PEEP required to prevent both end-inspiratory overdistension and end-expiratory alveolar collapse, thereby reducing ΔP, correlates positively with the body mass index (BMI) of patients, with PEEP values corresponding to approximately 1/3 of patient's respective BMI. Thus, we hypothesize that adjusting PEEP according to patient BMI reduces ΔP and may result in less postoperative pulmonary complications.

METHODS

Patients undergoing general anesthesia and endotracheal intubation with volume-controlled ventilation with a tidal volume of 7 ml per kg predicted body weight will be randomized and assigned to either an intervention group with PEEP adjusted according to BMI or a control group with a standardized PEEP of 5 mbar. Pre- and postoperatively, lung ultrasound will be performed to determine the lung aeration score, and hemodynamic and respiratory vital signs will be recorded for subsequent evaluation. The primary outcome is the difference in ΔP as a surrogate parameter for lung-protective ventilation. Secondary outcomes include change in lung aeration score, intraoperative occurrence of hemodynamic and respiratory events, oxygen requirements and postoperative pulmonary complications.

DISCUSSION

The study results will show whether an intraoperative ventilation strategy with PEEP adjustment based on BMI has the potential of reducing the risk for postoperative pulmonary complications as an easy-to-implement intervention that does not require lengthy ventilator maneuvers nor additional equipment.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS), DRKS00031336. Registered 21st February 2023.

TRIAL STATUS

The study protocol was approved by the ethics committee of the Christian-Albrechts-Universität Kiel, Germany, on 1st February 2023. Recruitment began in March 2023 and is expected to end in September 2023.

Lung Ultrasound Score on Postoperative Day 1 Is Predictive of the Occurrence of Pulmonary Complications after Major Abdominal Surgery: A Multicenter Prospective Observational Study

BACKGROUND

Postoperative pulmonary complications after major abdominal surgery are frequent and carry high morbidity and mortality. Early identification of patients at risk of pulmonary complications by lung ultrasound may allow the implementation of preemptive strategies. The authors hypothesized that lung ultrasound score would be associated with pulmonary postoperative complications. The main objective of the study was to evaluate the performance of lung ultrasound score on postoperative day 1 in predicting pulmonary complications after major abdominal surgery. Secondary objectives included the evaluation of other related measures for their potential prediction accuracy.

METHODS

A total of 149 patients scheduled for major abdominal surgery were enrolled in a bicenter observational study. Lung ultrasound score was performed before the surgery and on days 1, 4, and 7 after surgery. Pulmonary complications occurring before postoperative day 10 were recorded.

RESULTS

Lung ultrasound score on postoperative day 1 was higher in patients developing pulmonary complications before day 10 (median, 13; interquartile range, 8.25 to 18; vs. median, 10; interquartile range, 6.5 to 12; Mann-Whitney P = 0.002). The area under the curve for predicting postoperative pulmonary complications before day 10 was 0.65 (95% CI, 0.55 to 0.75; P = 0.003). Lung ultrasound score greater than 12 had a sensitivity of 0.54 (95% CI, 0.40 to 0.67), specificity of 0.77 (95% CI, 0.67 to 0.85), and negative predictive value of 0.74 (95% CI, 0.65 to 0.83). Lung ultrasound score greater than 17 had sensitivity of 0.33 (95% CI, 0.21 to 0.47), specificity of 0.95 (95% CI, 0.88 to 0.98), and positive predictive value of 0.78 (95% CI, 0.56 to 0.93). Anterolateral lung ultrasound score and composite scores using lung ultrasound score and other patient characteristics showed similar predictive accuracies.

CONCLUSIONS

An elevated lung ultrasound score on postoperative day 1 is associated with the occurrence of pulmonary complications within the first 10 days after major abdominal surgery.

EDITOR’S PERSPECTIVE

Exploration and Enhancement of Classifiers in the Detection of Lung Cancer from Histopathological Images

Lung cancer is a prevalent malignancy that impacts individuals of all genders and is often diagnosed late due to delayed symptoms. To catch it early, researchers are developing algorithms to study lung cancer images. The primary objective of this work is to propose a novel approach for the detection of lung cancer using histopathological images. In this work, the histopathological images underwent preprocessing, followed by segmentation using a modified approach of KFCM-based segmentation and the segmented image intensity values were dimensionally reduced using Particle Swarm Optimization (PSO) and Grey Wolf Optimization (GWO). Algorithms such as KL Divergence and Invasive Weed Optimization (IWO) are used for feature selection. Seven different classifiers such as SVM, KNN, Random Forest, Decision Tree, Softmax Discriminant, Multilayer Perceptron, and BLDC were used to analyze and classify the images as benign or malignant. Results were compared using standard metrics, and kappa analysis assessed classifier agreement. The Decision Tree Classifier with GWO feature extraction achieved good accuracy of 85.01% without feature selection and hyperparameter tuning approaches. Furthermore, we present a methodology to enhance the accuracy of the classifiers by employing hyperparameter tuning algorithms based on Adam and RAdam. By combining features from GWO and IWO, and using the RAdam algorithm, the Decision Tree classifier achieves the commendable accuracy of 91.57%.

Is a guideline required to predict the intensive care unit need of patients over 65 years of age during the pre-operative period? A comparison of the American Society of Anesthesiologists, lung ultrasound score, Charlson age-added comorbidity index, surgi

BACKGROUND

All pre-operative, intra-operative, and post-operative variables of the patients at 65 years of age who had a surgi-cal procedure determine the necessity of post-operative intensive care unit (ICU) monitoring. The indication for post-operative ICU is detected through ideal scoring systems related to the surgery and anesthesia that will be performed easily and fast would prevent the development of morbidity and mortality in high-risk patients. In the present study, we compared the efficacy of the American Society of Anesthesiologists (ASA) score, lung ultrasound score (LUSS), Charlson age-added comorbidity index (CACI), and surgical outcome risk tool (SORT) score of the indication for ICU. The hypothesis of our study is to show that real visual LUSS is superior to the screening test SORT, CACI, and the other score, ASA, for ICU indication determination.

METHODS

The study enrolled 101 patients over 65 years of age who will have surgical procedures under elective conditions. De-mographic features, clinical parameters, ICU indications, ASA, LUSS, CACI, and SORTs of the patients were calculated prospectively and recorded. The effects of patients' ASA, LUSS, CACI, and SORT on determining the need for postoperative ICU admission were examined.

RESULTS

The age of patients who needed post-operative ICU admission was significantly higher than those who did not need post-operative ICU admission (P<0.001). The groups did not show differences in terms of gender, body mass index, smoking, and type of anesthesia (P>0.05). ASA, LUSS, CACI, and SORT were significantly higher for patients who needed post-operative ICU admission (P<0.001). The proportion of patients who needed post-operative ICU admission was higher for patients with post-operative ICU indication (P<0.001). The number of consultations was significantly higher for patients who needed post-operative ICU admission (P<0.001). SORT was found to be the highest accuracy for predicting the need for post-operative ICU admission.

CONCLUSION

It was detected that ASA, LUSS, CACI, and SORT are effective for the determination of the ICU indication in the pre-operative evaluation process of patients over the age of 65 who had elective surgery. However, the efficiency of SORT was found to be superior to the others.

A preoperative ultrasound-based protocol for optimisation of fluid therapy to prevent early intraoperative hypotension: a randomised controlled study

BACKGROUND

Intraoperative hypotension is a risk factor for postoperative complications. Preoperative dehydration is a major contributor, although it is difficult to estimate its severity. Point-of-care ultrasound offers several potential methods, including measurements of the inferior vena cava. The addition of lung ultrasound may offer a safety limit. We aimed to evaluate whether the implication of an ultrasound-based preoperative fluid therapy protocol can decrease the incidence of early intraoperative hypotension.

METHODS

Randomised controlled study in a tertiary university department involves elective surgical patients of ASA 2-3 class, scheduled for elective major abdominal surgery under general anaesthesia with intubation. We randomised 40-40 patients; 38-38 were available for analysis. Conventional fluid therapy was ordered on routine preoperative visits. Ultrasound-based protocol evaluated the collapsibility index of inferior vena cava and lung ultrasound profiles. Scans were performed twice: 2 h and 30 min before surgery. A high collapsibility index (≥ 40%) indicated a standardised fluid bolus, while the anterior B-profile of the lung ultrasound contraindicated further fluid. The primary outcome was the incidence of postinduction and early intraoperative (0-10 min) hypotension (MAP < 65 mmHg and/or ≥ 30% of decrease from baseline). Secondary endpoints were postoperative lactate level, urine output and lung ultrasound score at 24 h.

RESULTS

The absolute criterion of postinduction hypotension was fulfilled in 12 patients in the conventional group (31.6%) and 3 in the ultrasound-based group (7.9%) (p = 0.0246). Based on composite criteria of absolute and/or relative hypotension, we observed 17 (44.7%) and 7 (18.4%) cases, respectively (p = 0.0136). The incidence of early intraoperative hypotension was also lower: HR for absolute hypotension was 2.10 (95% CI 1.00-4.42) in the conventional group (p = 0.0387). Secondary outcome measures were similar in the study groups.

CONCLUSION

We implemented a safe and effective point-of-care ultrasound-based preoperative fluid replacement protocol into perioperative care.

TRIAL REGISTRATION

The study was registered to ClinicalTrials.gov on 10/12/2021, registration number: NCT05171608 (registered prospectively on 10/12/2021).

Reliability and clinical correlations of semi-quantitative lung ultrasound on BLUE points in COVID-19 mechanically ventilated patients: The 'BLUE-LUSS'-A feasibility clinical study

INTRODUCTION

Bedside lung ultrasound has gained a key role in each segment of the treatment chain during the COVID-19 pandemic. During the diagnostic assessment of the critically ill patients in ICUs, it is highly important to maximize the amount and quality of gathered information while minimizing unnecessary interventions (e.g. moving/rotating the patient). Another major factor is to reduce the risk of infection and the workload of the staff.

OBJECTIVES

To serve these significant issues we constructed a feasibility study, in which we used a single-operator technique without moving the patient, only assessing the easily achievable lung regions at conventional BLUE points. We hypothesized that calculating this 'BLUE lung ultrasound score' (BLUE-LUSS) is a reasonable clinical tool. Furthermore, we used both longitudinal and transverse scans to measure their reliability and assessed the interobserver variability as well.

METHODS

University Intensive Care Unit based, single-center, prospective, observational study was performed on 24 consecutive SARS-CoV2 RT-PCR positive, mechanically ventilated critically ill patients. Altogether 400 loops were recorded, rated and assessed off-line by 4 independent intensive care specialists (each 7+ years of LUS experience).

RESULTS

Intraclass correlation values indicated good reliability for transversal and longitudinal qLUSS scores, while we detected excellent interrater agreement of both cLUSS calculation methods. All of our LUS scores correlated inversely and significantly to the P/F values. Best correlation was achieved in the case of longitudinal qLUSS (r = -0.55, p = 0.0119).

CONCLUSION

Summarized score of BLUE-LUSS can be an important, easy-to-perform adjunct tool for assessing and quantifying lung pathology in critically ill ventilated patients at bedside, especially for the P/F ratio. The best agreement for the P/F ratio can be achieved with the longitudinal scans. Regarding these findings, assessing BLUE-points can be extended with the BLUE-LUSS for daily routine using both transverse and longitudinal views.

Quantitative Lung Ultrasound: Technical Aspects and Clinical Applications

Lung ultrasound is increasingly used in emergency departments, medical wards, and critical care units-adult, pediatric, and neonatal. In vitro and in vivo studies show that the number and type of artifacts visualized change with lung density. This has led to the idea of a quantitative lung ultrasound approach, opening up new prospects for use not only as a diagnostic but also as a monitoring tool. Consequently, the multiple scoring systems proposed in the last few years have different technical approaches and specific clinical indications, adaptable for more or less time-dependent patients. However, multiple scoring systems may generate confusion among physicians aiming at introducing lung ultrasound in their clinical practice. This review describes the various lung ultrasound scoring systems and aims to clarify their use in different settings, focusing on technical aspects, validation with reference techniques, and clinical applications.