Mechanical power during robotic-assisted laparoscopic prostatectomy: an observational study.

BACKGROUND: Robotic-assisted laparoscopic radical prostatectomy (RALP) requires pneumoperitoneum and steep Trendelenburg position. Our aim was to investigate the influence of the combination of pneumoperitoneum and Trendelenburg position on mechanical power and its components during RALP. METHODS: Sixty-one prospectively enrolled patients scheduled for RALP were studied in supine position before surgery, during pneumoperitoneum and Trendelenburg position and in supine position after surgery at constant ventilatory setting. In a subgroup of 17 patients the response to increasing positive end-expiratory pressure (PEEP) from 5 to 10 cmH2O was studied. RESULTS: The application of pneumoperitoneum and Trendelenburg position increased the total mechanical power (13.8 [11.6 - 15.5] vs 9.2 [7.5 - 11.7] J/min, p < 0.001) and its elastic and resistive components compared to supine position before surgery. In supine position after surgery the total mechanical power and its elastic component decreased but remained higher compared to supine position before surgery. Increasing PEEP from 5 to 10 cmH2O within each timepoint significantly increased the total mechanical power (supine position before surgery: 9.8 [8.4 - 10.4] vs 12.1 [11.4 - 14.2] J/min, p < 0.001; pneumoperitoneum and Trendelenburg position: 13.8 [12.2 - 14.3] vs 15.5 [15.0 - 16.7] J/min, p < 0.001; supine position after surgery: 10.2 [9.4 - 10.7] vs 12.7 [12.0 - 13.6] J/min, p < 0.001), without affecting respiratory system elastance. CONCLUSION: Mechanical power in healthy patients undergoing RALP significantly increased both during the pneumoperitoneum and Trendelenburg position and in supine position after surgery. PEEP always increased mechanical power without ameliorating the respiratory system elastance.

Occurrence of secondary insults during endovascular treatment of acute ischemic stroke and impact on outcome: the SIR-STROKE prospective observational study.

BACKGROUND: Neurological outcome after endovascular treatment (EVT) of acute ischemic stroke (AIS) may depend on both patient-specific and procedural factors. We hypothesized that altered systemic homeostasis might be frequent and affect outcome in these patients. The aim of this study was to analyze secondary insults during EVT of AIS and its association with outcome and anesthesiologic regimen. METHODS: This was a single-center prospective observational study on patients undergoing EVT for AIS under local anesthesia (LA), conscious sedation (CS), or general anesthesia (GA). Altered systemic parameters were recorded and quantified as secondary insults. The primary endpoint was to evaluate number, duration, and severity of secondary insults during EVT. Secondary endpoints were to analyze association of insults with modified Rankin Scale at 90 days and anesthesiologic regimen. RESULTS AND CONCLUSIONS: One hundred twenty patients were enrolled. Overall, 78% of patients experienced at least one episode of hypotension, 21% hypertension, 54% hypoxemia, 16% bradycardia, and 13% tachycardia. In patients monitored with capnometry, 70% experienced hypocapnia and 21% hypercapnia. LA was selected in 24 patients, CS in 84, and GA in 12. Hypotension insult was more frequent during GA than LA and CS (p = 0.0307), but intraprocedural blood pressure variation was higher during CS (p = 0.0357). Hypoxemia was more frequent during CS (p = 0.0087). Proportion of hypotension duration was higher in unfavorable outcome but secondary insults did not remain in the final model of multivariable analysis. Secondary insults occurred frequently during EVT for AIS but the main predictors of outcome were age, NIHSS at admission, and prompt and successful recanalization.

Lung Imaging and Artificial Intelligence in ARDS.

Artificial intelligence (AI) can make intelligent decisions in a manner akin to that of the human mind. AI has the potential to improve clinical workflow, diagnosis, and prognosis, especially in radiology. Acute respiratory distress syndrome (ARDS) is a very diverse illness that is characterized by interstitial opacities, mostly in the dependent areas, decreased lung aeration with alveolar collapse, and inflammatory lung edema resulting in elevated lung weight. As a result, lung imaging is a crucial tool for evaluating the mechanical and morphological traits of ARDS patients. Compared to traditional chest radiography, sensitivity and specificity of lung computed tomography (CT) and ultrasound are higher. The state of the art in the application of AI is summarized in this narrative review which focuses on CT and ultrasound techniques in patients with ARDS. A total of eighteen items were retrieved. The primary goals of using AI for lung imaging were to evaluate the risk of developing ARDS, the measurement of alveolar recruitment, potential alternative diagnoses, and outcome. While the physician must still be present to guarantee a high standard of examination, AI could help the clinical team provide the best care possible.

Short-term effects of small volume saline infusion on acid base equilibrium in critically ill patients.

BACKGROUND: Short-term acid-base effects of 0.9% saline solution infusion are not well described. Aim of this study was to assess the effects of a fluid challenge with 0.9% saline in critically ill patients according to the Stewart's approach, which allows a precise determination of acid base equilibrium. METHODS: In 40 mechanically ventilated critically ill patients, acid-base variables according to Stewart's approach were measured before and after 30 minutes from the infusion of 0.5L of 0.9% saline. Patients were divided in saline responder (fractional sodium excretion increase <0.5) and non-responders, and in patients with (estimated glomerular filtration rate >63 mL/min) and without renal impairment. RESULTS: After saline infusion, plasma sodium concentration did not change (138 [135-141] vs. 138 [135-140] mEq/L, P=0.646), while chloride concentration significantly increased (102 [100-106] vs. 104 [191-106] mEq/L, P=0.003), reducing strong ion difference (37.0 [34.9-38.0] vs. 35.4 [32.7-37.5] mEq/L, P=0.004) without any impact on pH, due to the concomitant albumin dilution. In saline non-responders, the increase of plasma chloride concentration caused a reduction in strong ion difference, while in saline responders both plasma chloride concentration and strong ion difference remained similar. Patients with and without renal impairment presented a similar acid-base response. CONCLUSIONS: The infusion of 0.9% saline reduced strong ion difference by increasing plasma chloride concentration, with no effect on pH due to concomitant albumin dilution. Saline non-responders, characterized by the ability to excrete the sodium excess, were more likely to suffer the acidifying effects of saline infusion, while renal function did not affect the acid-base response to saline infusion.

Early time-course of respiratory mechanics, mechanical power and gas exchange in ARDS patients.

PURPOSE: To describe the clinical course of ARDS during the first three days of mechanical ventilation, to compare ventilatory setting, respiratory mechanics and gas exchange variables collected during the first three days of mechanical ventilation between patients who survived and died during intensive care unit (ICU) stay and to investigate the variables associated with mortality at ICU admission and throughout the first three days of mechanical ventilation. MATERIALS AND METHODS: Prospective observational study. Mechanically ventilated ARDS patients were studied at ICU admission and for the following three days. Univariate logistic regression models were performed for PaO2/FiO2 ratio, driving pressure and alveolar dead space fraction and for mechanical power and mechanical power ratio. RESULTS: Mechanical power ratio was higher in non survivors at ICU admission and over time; PaO2/FiO2 ratio was higher in survivors with a similar behavior over time in the two groups while alveolar dead space fraction was similar at ICU admission and over time between groups. Mechanical power ratio was the only physiological variable which remained consistently associated with ICU mortality throughout the study. CONCLUSIONS: The alteration in oxygenation, dead space, and mechanical power ratio should be assessed not at intensive care admission, but during the first days of mechanical ventilation to better predict outcome.

Mechanical power ratio threshold for ventilator-induced lung injury.

RATIONALE: Mechanical power (MP) is a summary variable incorporating all causes of ventilator-induced-lung-injury (VILI). We expressed MP as the ratio between observed and normal expected values (MPratio). OBJECTIVE: To define a threshold value of MPratio leading to the development of VILI. METHODS: In a population of 82 healthy pigs, a threshold of MPratio for VILI, as assessed by histological variables and confirmed by using unsupervised cluster analysis was 4.5. The population was divided into two groups with MPratio above or below the threshold. MEASUREMENTS AND MAIN RESULTS: We measured physiological variables every six hours. At the end of the experiment, we measured lung weight and wet-to-dry ratio to quantify edema. Histological samples were analyzed for alveolar ruptures, inflammation, alveolar edema, atelectasis. An MPratio threshold of 4.5 was associated with worse injury, lung weight, wet-to-dry ratio and fluid balance (all p < 0.001). After 48 h, in the two MPratio clusters (above or below 4.5), respiratory system elastance, mean pulmonary artery pressure and physiological dead space differed by 32%, 36% and 22%, respectively (all p < 0.001), being worse in the high MPratio group. Also, the changes in driving pressure, lung elastance, pulmonary artery occlusion pressure, central venous pressure differed by 17%, 64%, 8%, 25%, respectively (all p < 0.001). LIMITATIONS: The main limitation of this study is its retrospective design. In addition, the computation for the expected MP in pigs is based on arbitrary criteria. Different values of expected MP may change the absolute value of MP ratio but will not change the concept of the existence of an injury threshold. CONCLUSIONS: The concept of MPratio is a physiological and intuitive way to quantify the risk of ventilator-induced lung injury. Our results suggest that a mechanical power ratio > 4.5 MPratio in healthy lungs subjected to 48 h of mechanical ventilation appears to be a threshold for the development of ventilator-induced lung injury, as indicated by the convergence of histological, physiological, and anatomical alterations. In humans and in lungs that are already injured, this threshold is likely to be different.

Effectiveness of an Active and Continuous Surveillance Program for Intensive Care Units Infections Based on the EPIC III (Extended Prevalence of Infection in Intensive Care) Approach.

We evaluated the effectiveness of the Extended Prevalence of Infection in Intensive Care (EPIC) III data collection protocol as an active surveillance tool in the eight Intensive Care Units (ICUs) of the Intensive and Critical Care Department of the University Hospital of Turin. A total of 435 patients were included in a six-day study over 72 ICU beds. 42% had at least one infection: 69% at one site, 26% at two sites and 5% at three or more sites. ICU-acquired infections were the most common (64%), followed by hospital-associated infections (22%) and community-acquired (20%), considering that each patient may have developed more than one infection type. 72% of patients were receiving at least one antibiotic: 48% for prophylaxis and 52% for treatment. Mortality, the length of ICU and hospital stays were 13%, 14 and 29 days, respectively, being all estimated to be significantly different in patients without and with infection (8% vs. 20%; 4 vs. 20 and 11 vs. 50 (p < 0.001). Our data confirm a high prevalence of infections, sepsis and the use of antimicrobials. The repeated punctual prevalence survey seems an effective method to carry out the surveillance of infections and the use of antimicrobials in the ICU. The use of the European Centre for Disease Prevention and Control (ECDC) definitions and the EPIC III protocol seems strategic to allow comparisons with national and international contexts.