The respiratory and hemodynamic effects of alveolar recruitment in cirrhotic patients undergoing liver resection surgery: A randomized controlled trial.

Background and Aims: Extensive surgical retraction combined with general anesthesia increase alveolar collapse. The primary aim of our study was to investigate the effect of alveolar recruitment maneuver (ARM) on arterial oxygenation tension (PaO2). The secondary aim was to observe its effect on hemodynamics parameters in hepatic patients during liver resection, to investigate its impact on blood loss, postoperative pulmonary complications (PPC), remnant liver function tests, and on the outcome. Material and Methods: Adult patients scheduled for liver resection were randomized into two groups: ARM (n = 21) and control (C) (n = 21). Stepwise ARM was initiated after intubation and was repeated post-retraction. Pressure-control ventilation mode was adjusted to deliver a tidal volume (Vt) of 6 mL/kg and an inspiratory-to-expiratory time (I:E) ratio of 1:2 with an optimal positive end-expiratory pressure (PEEP) for the ARM group. In the C group, a fixed PEEP (5 cmH2O) was applied. Invasive intra-arterial blood pressure (IBP), central venous pressure (CVP), electrical cardiometry (EC), alanine transaminase (ALT, U/L), and aspartate aminotransferase (AST, U/L) blood levels were monitored. Results: ARM increased PEEP, dynamic compliances, and arterial oxygenation, but reduced ventilator driving pressure compared to group C (P < 0.01). IBP, cardiac output (CO), and stroke volume variation were not affected by the higher PEEP in the ARM group (P > 0.05) but the CVP increased significantly (P = 0.001). Blood loss was not different between the ARM and C groups (1700 (1150-2000) mL vs 1110 (900-2400) mL, respectively and P = 0.57). ARM reduced postoperative oxygen desaturation; however, it did not affect the increase in remnant liver enzymes and was comparable to group C (ALT, P = 0.54, AST, P = 0.41). Conclusions: ARM improved intraoperative lung mechanics and reduced oxygen desaturation episodes in recovery, but not PPC or ICU stay. ARM was tolerated with minimal cardiac and systemic hemodynamic effects.

Inhaled Sedation with Volatile Anesthetics for Mechanically Ventilated Patients in Intensive Care Units: A Narrative Review.

Inhaled sedation was recently approved in Europe as an alternative to intravenous sedative drugs for intensive care unit (ICU) sedation. The aim of this narrative review was to summarize the available data from the literature published between 2005 and 2023 in terms of the efficacy, safety, and potential clinical benefits of inhaled sedation for ICU mechanically ventilated patients. The results indicated that inhaled sedation reduces the time to extubation and weaning from mechanical ventilation and reduces opioid and muscle relaxant consumption, thereby possibly enhancing recovery. Several researchers have reported its potential cardio-protective, anti-inflammatory or bronchodilator properties, alongside its minimal metabolism by the liver and kidney. The reflection devices used with inhaled sedation may increase the instrumental dead space volume and could lead to hypercapnia if the ventilator settings are not optimal and the end tidal carbon dioxide is not monitored. The risk of air pollution can be prevented by the adequate scavenging of the expired gases. Minimizing atmospheric pollution can be achieved through the judicious use of the inhalation sedation for selected groups of ICU patients, where the benefits are maximized compared to intravenous sedation. Very rarely, inhaled sedation can induce malignant hyperthermia, which prompts urgent diagnosis and treatment by the ICU staff. Overall, there is growing evidence to support the benefits of inhaled sedation as an alternative for intravenous sedation in ICU mechanically ventilated patients. The indication and management of any side effects should be clearly set and protocolized by each ICU. More randomized controlled trials (RCTs) are still required to investigate whether inhaled sedation should be prioritized over the current practice of intravenous sedation.

Plethysmography Variability Index and Stroke Volume Variation Changes in Relation to Central Venous Pressure Changes During Living Related Donor Right Hepatotomy: A Diagnostic Test Accuracy.

OBJECTIVES: During donor hepatectomy, we investigated (1) the Electrical Cardiometry associations and agreements between noninvasive plethysmography variability index and noninvasive stroke volume variation, (2) their association with central venous pressure, and (3) their ability to monitor intraoperative changes and discriminate donors with increased blood loss. MATERIALS AND METHODS: A diagnostic test accuracy was applied among donors (American Society of Anesthesiologists classification I). Data were recorded at 10 minutes after anesthesia induction, hourly during dissection, after resection, and at end of surgery. Crystalloids were restricted during resection to reduce central venous pressure but were otherwise infused to maintain mean invasive arterial blood pressure >60 mm Hg and urine output >0.5 mL/kg/h. RESULTS: All 34 donors were related. Sons or daughters represented 58.8% (median age 26.0 years [interquartile range, 21.0-34.0]). Median values (with interquartile ranges) were anesthesia time, 7.5 hours (7.0-8.0); blood loss, 400 mL (400.0-500.0); infused acetated Ringer solution, 4000.0 mL (3500.0-4500.0); colloids, 250.0 mL (0-500.0); and urine output, 1.4 mL/kg/h (1.30-1.7). No blood products were transfused. Central venous pressure showed negligible negative correlations for both plethysmography variability index and stroke volume variation. Plethysmography variability index showed negligible correlation and poor agreement with stroke volume variation (P < .001, with intraclass correlation = 0.213 and a relatively wide bias; 95% CI, 0.03-0.37). All 3 methods reflected a state of normovolemia despite fluid restriction during resection and were unable to discriminate donors with increased blood loss (>400 mL). CONCLUSIONS: Plethysmography variability index and stroke volume variation showed negligible correlation and poor agreement with central venous pressure. Transfusion-free dissection was possible despite normovolemia, with median values of 8 mm Hg central venous pressure, 10% stroke volume variation, and 12% plethysmography variability index. Plethysmography variability index and stroke volume variation were unable to discriminate donors with increased blood loss.

Respiratory and Hemodynamic Effects of Prophylactic Alveolar Recruitment During Liver Transplant: A Randomized Controlled Trial.

OBJECTIVES: Prolonged surgical retraction may cause atelectasis. We aimed to recruit collapsed alveoli, stepwise, monitored by lung dynamic compliance and observe effects on arterial oxygenation and systemic and graft hemodynamics. Secondarily, we observed alveolar recruitment effects on postoperative mechanical ventilation, international normalized ratio, and pulmonary complications. MATERIALS AND METHODS: For 58 recipients (1 excluded), randomized with optimal positive end-expiratory pressure (n = 28) versus control (fixed positive end-expiratory pressure, 5 cm H2O; n = 29), alveolar recruitment was initiated (pressure-controlled ventilation guided by lung dynamic compliance) to identify optimal conditions. Ventilation shifted to volume-control mode with 0.4 fraction of inspired oxygen, 6 mL/kg tidal volume, and 1:2 inspiratory-to-expiratory ratio. Alveolar recruitment was repeated postretraction and at intensive care unit admission. Primary endpoints were changes in lung dynamic compliance, arterial oxygenation, and hemodynamics (cardiac output, invasive arterial and central venous pressures, graft portal and hepatic vein flows). Secondary endpoints were mechanical ventilation period and postoperative international normalized ratio, aspartate/alanine aminotransferases, lactate, and pulmonary complications. RESULTS: Alveolar recruitment increased positive end-expiratory pressure, lung dynamic compliance, and arterial oxygenation (P < .01) and central venous pressure (P = .004), without effects on corrected flow time (P = .7). Cardiac output and invasive arterial pressure were stable with (P = .11) and without alveolar recruitment (P = .1), as were portal (P = .27) and hepatic vein flow (P = .30). Alveolar recruitment reduced postoperative pulmonary complications (n = 0/28 vs 8/29; P = .001), without reduction in postoperative mechanical ventilation period (P = .08). International normalization ratio, aspartate/alanine aminotransferases, and lactate were not different from control (P > .05). CONCLUSIONS: Stepwise alveolar recruitment identified the optimal positive end-expiratory pressure to improve lung mechanics and oxygenation with minimal hemodynamic changes, without liver graft congestion/dysfunction, and was associated with significant reduction in postoperative pulmonary complications.

The role of rotational thromboelastometry during the COVID-19 pandemic: a narrative review.

The coronavirus disease 2019 (COVID-19) pandemic is currently recognized as a global health crisis. This viral infection is frequently associated with hypercoagulability, with a high incidence of thromboembolic complications that can be fatal. In many situations, the standard coagulation tests (SCT) fail to detect this state of hypercoagulability in patients with COVID-19 since clotting times are either not or only mildly affected. The role of viscoelastic tests such as rotational thromboelastometry (ROTEM®) during this pandemic is explored in this review. COVID-19-associated coagulopathy, as measured using the rotational thromboelastometry parameters, can vary from hypercoagulability due to increased fibrin polymerization and decreased fibrinolysis to bleeding from hypocoagulability. The use of a multimodal diagnostic and monitoring approach, including both rotational thromboelastometry and SCT, such as plasma fibrinogen and D-dimer concentrations, is recommended. Rotational thromboelastometry provides comprehensive information about the full coagulation status of each patient and detects individual variations. Since COVID-19-associated coagulopathy is a very dynamic process, the phenotype can change during the course of infection and in response to anticoagulation therapy. Data from published literature provide evidence that the combination of rotational thromboelastometry and SCT analysis is helpful in detecting hemostasis issues, guiding anticoagulant therapy, and improving outcomes in COVID-19 patients. However, more research is needed to develop evidence-based guidelines and protocols.