No abstract

European Society of Anaesthesiology.

Rationale: Obesity is characterized by elevated pleural pressure (P PL) and worsening atelectasis during mechanical ventilation in patients with acute respiratory distress syndrome (ARDS). Objectives: To determine the effects of lung recruitment maneuver (LRM) in the presence of elevated P PL on hemodynamics, left and right ventricular pressures and pulmonary vascular resistance. We hypothesized that elevated P PL protects the cardiovascular system against high airway pressures and prevents lung overdistension. Methods: First, an interventional crossover trial in adult subjects with ARDS and BMI≥35 kg/m 2 (n=21) was performed to explore the hemodynamic consequences of LRM. Second, cardiovascular function was studied during low/high PEEPs in a model of swine with ARDS and high P PL (n=9) versus healthy swine with normal P PL (n=6). Measurements and Main Results: Subjects with ARDS and obesity (BMI=57±12 kg/m 2) following LRM, required an increase in PEEP of 8[7, 10] cmH 2 O above traditional ARDSnet settings to improve lung function, oxygenation and ventilation/perfusion matching, without impairment of hemodynamics or right heart function. ARDS swine with high P PL demonstrated unchanged transmural left ventricle pressure and systemic blood pressure after LRM protocol. Pulmonary artery hypertension decreased 8[13, 4] mmHg, as did vascular resistance 1.5[2.2, 0.9] WU, and transmural right ventricle pressure 10[15, 6] mmHg during exhalation. LRM and PEEP decreased pulmonary vascular resistance and normalized ventilation/perfusion ratio.

The role of trunk inclination on respiratory function has been explored in patients with "typical" Acute Respiratory Distress Syndrome (ARDS) (1-3). Data regarding patients with COVID-19-associated ARDS (C-ARDS) are currently lacking.Aim of our study was to assess the effects of changes in trunk inclination on lung mechanics and gas exchange in mechanically ventilated patients with C-ARDS. MethodsThis single-center physiological cross-over study (ethical committee approval #70-11022021) was conducted on adult patients admitted to our COVID-ICU between March 3 and May 4, 2021. Diagnosis of C-ARDS, deep sedation, paralysis, and volume-controlled mechanical ventilation, were the inclusion criteria. Contraindications to mobilization (e.g., intracranial hypertension, spinal cord injury, tracheal lesions) and pregnancy constituted exclusion criteria. Patients were enrolled according to study personnel availability. A 5-Fr esophageal balloon (CooperSurgical, Trumbull, Connecticut) was inserted. The balloon was inflated with 1 ml of air and the correct position/function was verified before each measurement (4).Mechanical ventilation parameters, kept constant throughout the study, were set by the attending physician. Usually, PEEP is set according to the best respiratory system compliance (C RS ) assessed with a recruitment maneuver followed by a decremental PEEP trial. Of note, trunk inclination during PEEP selection is not standardized.Patients underwent three 15-minute steps in which trunk inclination was changed from 40° (semi-recumbent, baseline) to 0° (supine-flat), and back to 40° during the last step.At the end of each step, partitioned respiratory mechanics, arterial/central venous blood gas analysis and basic hemodynamics were recorded. Ventilatory ratio was calculated.

IntroductionPostoperative acute kidney injury (AKI) is a common complication in cardiac surgery. Levels of intravascular haemolysis are strongly associated with postoperative AKI and with prolonged (>90 min) use of cardiopulmonary bypass (CPB). Ferrous plasma haemoglobin released into the circulation acts as a scavenger of nitric oxide (NO) produced by endothelial cells. Consequently, the vascular bioavailability of NO is reduced, leading to vasoconstriction and impaired renal function. In patients with cardiovascular risk factors, the endothelium is dysfunctional and cannot replenish the NO deficit. A previous clinical study in young cardiac surgical patients with rheumatic fever, without evidence of endothelial dysfunction, showed that supplementation of NO gas decreases AKI by converting ferrous plasma haemoglobin to ferric methaemoglobin, thus preserving vascular NO. In this current trial, we hypothesised that 24 hours administration of NO gas will reduce AKI following CPB in patients with endothelial dysfunction.MethodsThis is a single-centre, randomised (1:1) controlled, parallel-arm superiority trial that includes patients with endothelial dysfunction, stable kidney function and who are undergoing cardiac surgery procedures with an expected CPB duration >90 min. After randomisation, 80 parts per million (ppm) NO (intervention group) or 80 ppm nitrogen (N2, control group) are added to the gas mixture. Test gases (N2or NO) are delivered during CPB and for 24 hours after surgery. The primary study outcome is the occurrence of AKI among study groups. Key secondary outcomes include AKI severity, occurrence of renal replacement therapy, major adverse kidney events at 6 weeks after surgery and mortality. We are recruiting 250 patients, allowing detection of a 35% AKI relative risk reduction, assuming a two-sided error of 0.05.Ethics and disseminationThe Partners Human Research Committee approved this trial. Recruitment began in February 2017. Dissemination plans include presentations at scientific conferences, scientific publications and advertising flyers and posters at Massachusetts General Hospital.Trial registration numberNCT02836899.

Objective To quantify how the first public announcement of confirmed coronavirus disease 2019 (COVID‐19) in Italy affected a metropolitan region's emergency medical services (EMS) call volume and how rapid introduction of alternative procedures at the public safety answering point (PSAP) managed system resources. Methods PSAP processes were modified over several days including (1) referral of non‐ill callers to public health information call centers; (2) algorithms for detection, isolation, or hospitalization of suspected COVID‐19 patients; and (3) specialized medical teams sent to the PSAP for triage and case management, including ambulance dispatches or alternative dispositions. Call volumes, ambulance dispatches, and response intervals for the 2 weeks after announcement were compared to 2017–2019 data and the week before. Results For 2 weeks following outbreak announcement, the primary‐level PSAP (police/fire/EMS) averaged 56% more daily calls compared to prior years and recorded 9281 (106% increase) on Day 4, averaging ∼400/hour. The secondary‐level (EMS) PSAP recorded an analogous 63% increase with 3863 calls (∼161/hour; 264% increase) on Day 3. The COVID‐19 response team processed the more complex cases (n = 5361), averaging 432 ± 110 daily (∼one‐fifth of EMS calls). Although community COVID‐19 cases increased exponentially, ambulance response intervals and dispatches (averaging 1120 ± 46 daily) were successfully contained, particularly compared with the week before (1174 ± 40; P = 0.02). Conclusion With sudden escalating EMS call volumes, rapid reorganization of dispatch operations using tailored algorithms and specially assigned personnel can protect EMS system resources by optimizing patient dispositions, controlling ambulance allocations and mitigating hospital impact. Prudent population‐based disaster planning should strongly consider pre‐establishing similar highly coordinated medical taskforce contingencies.

Patients with acute pancreatitis (AP) often require ICU admission, especially when signs of multiorgan failure are present, a condition that defines AP as severe. This disease is characterized by a massive pancreatic release of pro-inflammatory cytokines that causes a systemic inflammatory response syndrome and a profound intravascular fluid loss. This leads to a mixed hypovolemic and distributive shock and ultimately to multiorgan failure. Aggressive fluid resuscitation is traditionally considered the mainstay treatment of AP. In fact, all available guidelines underline the importance of fluid therapy, particularly in the first 24–48 h after disease onset. However, there is currently no consensus neither about the type, nor about the optimal fluid rate, total volume, or goal of fluid administration. In general, a starting fluid rate of 5–10 ml/kg/h of Ringer’s lactate solution for the first 24 h has been recommended. Fluid administration should be aggressive in the first hours, and continued only for the appropriate time frame, being usually discontinued, or significantly reduced after the first 24–48 h after admission. Close clinical and hemodynamic monitoring along with the definition of clear resuscitation goals are fundamental. Generally accepted targets are urinary output, reversal of tachycardia and hypotension, and improvement of laboratory markers. However, the usefulness of different endpoints to guide fluid therapy is highly debated. The importance of close monitoring of fluid infusion and balance is acknowledged by most available guidelines to avoid the deleterious effect of fluid overload. Fluid therapy should be carefully tailored in patients with severe AP, as for other conditions frequently managed in the ICU requiring large fluid amounts, such as septic shock and burn injury. A combination of both noninvasive clinical and invasive hemodynamic parameters, and laboratory markers should guide clinicians in the early phase of severe AP to meet organ perfusion requirements with the proper administration of fluids while avoiding fluid overload. In this narrative review the most recent evidence about fluid therapy in severe AP is discussed and an operative algorithm for fluid administration based on an individualized approach is proposed.

Background External chest-wall compression (ECC) is sometimes used in ARDS patients despite lack of evidence. It is currently unknown whether this practice has any clinical benefit in patients with COVID-19 ARDS (C-ARDS) characterized by a respiratory system compliance (Crs) < 35 mL/cmH2O. Objectives To test if an ECC with a 5 L-bag in low-compliance C-ARDS can lead to a reduction in driving pressure (DP) and improve gas exchange, and to understand the underlying mechanisms. Methods Eleven patients with low-compliance C-ARDS were enrolled and underwent 4 steps: baseline, ECC for 60 min, ECC discontinuation and PEEP reduction. Respiratory mechanics, gas exchange, hemodynamics and electrical impedance tomography were recorded. Four pigs with acute ARDS were studied with ECC to understand the effect of ECC on pleural pressure gradient using pleural pressure transducers in both non-dependent and dependent lung regions. Results Five minutes of ECC reduced DP from baseline 14.2 ± 1.3 to 12.3 ± 1.3 cmH2O (P < 0.001), explained by an improved lung compliance. Changes in DP by ECC were strongly correlated with changes in DP obtained with PEEP reduction (R2 = 0.82, P < 0.001). The initial benefit of ECC decreased over time (DP = 13.3 ± 1.5 cmH2O at 60 min, P = 0.03 vs. baseline). Gas exchange and hemodynamics were unaffected by ECC. In four pigs with lung injury, ECC led to a decrease in the pleural pressure gradient at end-inspiration [2.2 (1.1–3) vs. 3.0 (2.2–4.1) cmH2O, P = 0.035]. Conclusions In C-ARDS patients with Crs < 35 mL/cmH2O, ECC acutely reduces DP. ECC does not improve oxygenation but it can be used as a simple tool to detect hyperinflation as it improves Crs and reduces Ppl gradient. ECC benefits seem to partially fade over time. ECC produces similar changes compared to PEEP reduction.