'Walking epidural': comparison of the analgesic efficacy of levobupivacaine 0.0625% + fentanyl 2mcg/mL versus ropivacaine 0.075% + fentanyl 2mcg/mL.

INTRODUCTION: Epidural infusion with low local anesthetic concentrations with opiates decrease the severity of the motor blockade associated. The present study aims to compare the analgesic efficacy and the motor blockade between two local anesthetic epidural infusions: levobupivacaine 0.0625% + fentanyl 2mcg/mL versus ropivacaine 0.075% + fentanyl 2mcg/mL. MATERIALS AND METHODS: In a single-blind prospective randomized study, 60 laboring parturient had continuous epidural analgesia as follows: 30 of them received levobupivacaine 0.0625% + fentanyl 2mcg/mL and 30 of them received ropivacaine 0.075% + fentanyl 2mcg/mL and rates of infusion were adjusted to the height. Analgesic, motor blockade and satisfaction records were collected as well as maternal and neonate adverse events. RESULTS: After 2 h of the catheter placement, patients who received levobupivacaine showed a mean VAS of 3.2 [1.8-4.6] versus 1.8 [1.2-2.5] (p = 0.05) in patients who received ropivacaine. In addition, patients who received levobupivacaine showed a punctuation in Bromage scale of 0.0 [0.0-1.0] versus 0.0 [0.0-0.0] (p = 0.04) in patients who received ropivacaine. Finally, the parturient who received levobupivacaine scored a mean satisfaction index of 8.1 [7.3-8.9] versus 9.3 [8.7-9.8] (p = 0.02) in those who received ropivacaine. We did not register maternal nor neonate adverse events. CONCLUSION: Both infusions (levobupivacaine 0.0625% + fentanyl 2mcg/mL and ropivacaine 0.075% + fentanyl 2mcg/mL) are effective for labor analgesia. However, ropivacaine would present a better pharmacodynamic profile with less motor blockade and decreased need for analgesic rescue hence improving patient's satisfaction.

Individualizing mechanical ventilation: titration of driving pressure to pulmonary elastance through Young's modulus in an acute respiratory distress syndrome animal model.

BACKGROUND: Mechanical ventilation increases the risk of lung injury (VILI). Some authors propose that the way to reduce VILI is to find the threshold of driving pressure below which VILI is minimized. In this study, we propose a method to titrate the driving pressure to pulmonary elastance in an acute respiratory distress syndrome model using Young's modulus and its consequences on ventilatory-induced lung injury. MATERIAL AND METHODS: 20 Wistar Han male rats were used. After generating an acute respiratory distress syndrome, two groups were studied: (a) standard protective mechanical ventilation: 10 rats received 150 min of mechanical ventilation with driving pressure = 14 cm H2O, tidal volume < 6 mL/kg) and (b) individualized mechanical ventilation: 10 rats received 150 min of mechanical ventilation with an individualized driving pressure according to their Young's modulus. In both groups, an individualized PEEP was programmed in the same manner. We analyzed the concentration of IL-6, TNF-α, and IL-1ß in BAL and the acute lung injury score in lung tissue postmortem. RESULTS: Global driving pressure was different between the groups (14 vs 11 cm H2O, p = 0.03). The individualized mechanical ventilation group had lower concentrations in bronchoalveolar lavage of IL-6 (270 pg/mL vs 155 pg/mL, p = 0.02), TNF-α (292 pg/mL vs 139 pg/mL, p < 0.01) and IL-1ß (563 pg/mL vs 131 pg/mL, p = 0.05). They presented lower proportion of lymphocytes (96% vs 79%, p = 0.05) as well as lower lung injury score (6.0 points vs 2.0 points, p = 0.02). CONCLUSION: In our model, individualization of DP to pulmonary elastance through Young's modulus decreases lung inflammation and structural lung injury without a significant impact on oxygenation.

sST2 and Galectin-3 genotyping in patients with persistent atrial fibrillation.

Genotyping of ST2 and galectin-3 in atrial fibrillation (AF) is not well analyzed. The aim of our study was to analyze the possible relationship between levels of sST2 and galectin-3 and three polymorphisms in patients with AF. We included 125 patients with persistent AF undergoing electric cardioversion. We analyzed sST2 and galectin-3 levels and three polymorphisms in peripheral blood samples. Rs2274273 was significantly related with levels of galectin-3. Rs1558648 was associated with levels of sST2 but rs13019803 were not. None of the polymorphisms were connected to the variation of biomarkers levels during the follow up. We found a relationship between rs2274273 and galectin-3 levels and rs1558648 and sST2 levels in patients with AF.

Prevalence and clinical consequences of atelectasis in SARS-CoV-2 pneumonia: a computed tomography retrospective cohort study.

BACKGROUND: The aim of the study is to estimate the prevalence of atelectasis assessed with computer tomography (CT) in SARS-CoV-2 pneumonia and the relationship between the amount of atelectasis with oxygenation impairment, Intensive Care Unit admission rate and the length of in-hospital stay. PATIENTS AND METHODS: Two-hundred thirty-seven patients admitted to the hospital with SARS-CoV-2 pneumonia diagnosed by clinical, radiology and molecular tests in the nasopharyngeal swab who underwent a chest computed tomography because of a respiratory worsening from Apr 1 to Apr 30, 2020 were included in the study. Patients were divided into three groups depending on the presence and amount of atelectasis at the computed tomography: no atelectasis, small atelectasis (< 5% of the estimated lung volume) or large atelectasis (> 5% of the estimated lung volume). In all patients, clinical severity, oxygen-therapy need, Intensive Care Unit admission rate, the length of in-hospital stay and in-hospital mortality data were collected. RESULTS: Thirty patients (19%) showed small atelectasis while eight patients (5%) showed large atelectasis. One hundred and seventeen patients (76%) did not show atelectasis. Patients with large atelectasis compared to patients with small atelectasis had lower SatO2/FiO2 (182 vs 411 respectively, p = 0.01), needed more days of oxygen therapy (20 vs 5 days respectively, p = 0,02), more frequently Intensive Care Unit admission (75% vs 7% respectively, p < 0.01) and a longer period of hospitalization (40 vs 14 days respectively p < 0.01). CONCLUSION: In patients with SARS-CoV-2 pneumonia, atelectasis might appear in up to 24% of patients and the presence of larger amount of atelectasis is associated with worse oxygenation and clinical outcome.

Safety and efficacy evaluation of the automatic stepwise recruitment maneuver in the neonatal population: An in vivo interventional study. Can anesthesiologists safely perform automatic lung recruitment maneuvers in neonates?

BACKGROUND: A new software has recently been incorporated in almost all new anesthesia machines to enable automatic lung recruitment maneuvers. To date, no studies have assessed the safety and efficacy of these automatic software programs in the neonatal population. AIMS: We aimed to evaluate the safety and efficacy of the lung recruitment maneuver performed using the automatic stepwise recruitment maneuver software of the FLOW-i 4.3 Anesthesia System® in a healthy and live neonatal model. METHODS: Eight male newborn piglets were included in the study. The lung recruitment maneuver was performed in pressure-controlled ventilation with a constant driving pressure (15 cmH2 O) in a stepwise increasing positive end-expiratory pressure (PEEP) model. The target peak inspiratory pressure (PIP) was 30 cmH2 O and PEEP was 15 cmH2 O. The maneuver lasted for 39 seconds. The hemodynamic variables were monitored using the PICCO® system. The following respiratory parameters were monitored: oxygen saturation, fraction of inspired oxygen, partial pressure of oxygen and carbon dioxide in the arterial blood, end-tidal carbon dioxide pressure, PIP, plateau pressure, PEEP, static compliance (Cstat ), and dynamic compliance (Cdyn ). Safety was evaluated by assessing the accuracy of the software, need for not interrupting the maneuver, hemodynamic stability, and absence of adverse respiratory events with the lung recruitment maneuver. Efficacy was evaluated by improvement in Cstat and Cdyn after performing the lung recruitment maneuver. RESULTS: All lung recruitment maneuvers were safely performed as scheduled without any interruptions. No pneumothorax or other side effects were observed. Hemodynamic stability was maintained during the lung recruitment maneuver. We observed an improvement of 33% in Cdyn and 24% in Cstat after the maneuver. CONCLUSIONS: The automatic stepwise recruitment maneuver software of the FLOW-i 4.3 Anesthesia System® is safe and efficacious in a healthy neonatal model. We did not observe any adverse respiratory or hemodynamic events during the implementation of the lung recruitment maneuver in the pressure-controlled ventilation mode using a stepwise increasing PEEP (30/15 cmH2 O) approach.

Tramadol-induced hyperalgesia and its prevention by ketamine in rats: A randomised experimental study.

BACKGROUND: Opioid analgesia not only reduces inhalational anaesthetic requirements but may also induce delayed hyperalgesia, with potential effects on the minimum alveolar concentration (MAC) of inhalational anaesthetics. OBJECTIVES: The objective of this study was to evaluate the development of tramadol-induced hyperalgesia and the associated changes in MAC, and whether ketamine prevents both processes. DESIGN: A randomised, experimental study. SETTING: Experimental Surgery Unit, La Paz University Hospital, Madrid, Spain. ANIMALS: Thirty-nine adult male Wistar rats. INTERVENTIONS: Mechanical nociceptive thresholds (MNT) were determined up to 21 days after the intraperitoneal administration of a single dose of tramadol (50 mg kg) with or without ketamine (10 mg kg), or 0.9% saline. The MNT and the MAC of sevoflurane were also assessed in a second experiment before, early (30 min) and 7 days after drug administration with the same treatments. MAIN OUTCOME MEASURES: The MAC and MNT were evaluated. The analysis of variance (ANOVA) test was employed to determine differences between treatments and times on MAC and MNT. RESULTS: Tramadol, alone or combined with ketamine, produced an early increase in MNT. However, tramadol given alone decreased MNT from day 1 up to 3 weeks, which was associated with an increase in the MAC of sevoflurane (P < 0.05; day 7). Ketamine administration prevented both the reduction in MNT and the increase in MAC (P > 0.05). CONCLUSION: Tramadol-induced hyperalgesia in the rat lasted for several weeks and was associated with an increase in the MAC of sevoflurane. Prior administration of ketamine blocked both phenomena.

Hyperalgesia and increased sevoflurane minimum alveolar concentration induced by opioids in the rat: a randomised experimental study.

BACKGROUND: Perioperative opioids reduce inhalational anaesthetic requirements. The initial hypoalgesia may, however, be followed by a rebound hyperalgesia. OBJECTIVES: To determine whether prior opioid administration influences inhalational anaesthetic requirements, which might be associated with opioid-induced hyperalgesia. DESIGN: A prospective, randomised, experimental study. SETTING: Experimental Surgery, La Paz University Hospital, Madrid, Spain. ANIMALS: Seventy-nine adult male Wistar rats. INTERVENTIONS: Sevoflurane minimum alveolar concentration (MAC) and mechanical nociceptive thresholds (MNTs) were assessed at baseline and 7 days later following opioid treatment with remifentanil 120 µg  kg-1  h-1, buprenorphine 150 µg kg-1, methadone 8 mg  kg-1 or morphine 10 mg  kg-1 The duration of the effect of remifentanil on MAC and MNT was evaluated in addition to the preventive effect of ketamine 10 mg  kg-1 on remifentanil-induced hyperalgesia. MAIN OUTCOME MEASURES: The effect of different opioid treatments on MAC and MNT was evaluated using analysis of variance (ANOVA). RESULTS: All studied opioids produced an immediate reduction in sevoflurane MAC, followed by an increase (16%) in baseline MAC 7 days later (P < 0.05), although the immediate MAC reduction produced by these opioids at that time was not different. Remifentanil produced a decrease in MNT (P < 0.05), which was associated with an increase in the MAC (P < 0.05) that persisted at 21 days. The effect of remifentanil on MNT and MAC was blocked by ketamine. CONCLUSION: Opioid-induced hyperalgesia was associated with an increase in the MAC in normal rats who had not undergone surgery. Both effects lasted 21 days and were prevented by ketamine.

Amitriptyline, minocycline and maropitant reduce the sevoflurane minimum alveolar concentration and potentiate remifentanil but do not prevent acute opioid tolerance and hyperalgesia in the rat: a randomised laboratory study.

BACKGROUND: The antidepressant amitriptyline, the inhibitor of microglia activation minocycline, and the neurokinin-1 antagonist maropitant have all been used to prevent or treat hyperalgesia and opioid tolerance. OBJECTIVES: To determine the effect of amitriptyline, minocycline, maropitant, independently or with remifentanil, on the sevoflurane minimum alveolar concentration in rats and whether these drugs may block opioid-induced hyperalgesia and acute opioid tolerance under inhalational anaesthesia. DESIGN: A randomised, laboratory study. SETTING: Experimental Unit, La Paz University Hospital, Madrid, Spain. ANIMALS: One hundred and fourteen adult male Wistar rats. INTERVENTIONS: Intraperitoneal administration of amitriptyline (10 and 50  mg  kg-1), minocycline (30 and 100  mg  kg-1), maropitant (10 and 30 mg  kg-1) or isotonic saline, combined with a constant rate intravenous infusion of remifentanil (240 µg  kg-1  h-1) or saline. MAIN OUTCOME MEASURES: Sevoflurane minimum alveolar concentration was determined before and after administration of the drugs; acute opioid tolerance was defined as a decreased ability of remifentanil to reduce the minimum alveolar concentration in the short term. In addition, mechanical nociceptive thresholds were determined before and after these treatments. Opioid-induced hyperalgesia was defined as an increase in mechanical nociceptive thresholds after opioid administration. RESULTS: Amitriptyline, minocycline and maropitant reduced minimum alveolar concentration up to 24 (8)%, 23 (6)% and 15 (5)%, respectively (P <0.001). Remifentanil alone reduced minimum alveolar concentration by 36 (6)% (P <0.001), and in combination with amitriptyline, minocycline and maropitant, the reduction was 76 (9)%, 75 (16)% and 59 (5)%, respectively (P <0.001). An acute tolerance effect (P < 0.01) and a decrease in the mechanical nociceptive thresholds were observed with remifentanil in all groups. CONCLUSION: Amitriptyline, minocycline and maropitant reduced the minimum alveolar concentration and potentiated the remifentanil minimum alveolar concentration reduction but failed to block opioid-induced hyperalgesia and acute opioid tolerance.

Lung recruitment manoeuvres do not cause haemodynamic instability or oxidative stress but improve oxygenation and lung mechanics in a newborn animal model: an observational study.

BACKGROUND: Lung recruitment manoeuvres in neonates during anaesthesia are not performed routinely due to concerns about causing barotrauma, haemodynamic instability and oxidative stress. OBJECTIVE: To assess the influence of recruitment manoeuvres and positive end-expiratory pressure (PEEP) on haemodynamics, oxidative stress, oxygenation and lung mechanics. DESIGN: A prospective experimental study. SETTING: Experimental Unit, La Paz University Hospital, Madrid, Spain. ANIMALS: Eight newborn piglets (<48 h) with healthy lungs under general anaesthesia. INTERVENTIONS: The recruitment manoeuvres in pressure-controlled ventilation (PCV) were performed along with a constant driving pressure of 15 cmH2O. After the recruitment manoeuvres, PEEP was reduced in a stepwise fashion to find the maximal dynamic compliance step (maxCDyn-PEEP). Blood oxidative stress biomarkers (lipid peroxidation products, protein carbonyls, total glutathione, oxidised glutathione, reduced glutathione and activity of glutathione peroxidase) were analysed. MAIN OUTCOME MEASURES: Haemodynamic parameters, arterial partial pressure of oxygen (paO2), tidal volume (Vt), dynamic compliance (Cdyn) and oxidative stress biomarkers were measured. RESULTS: The recruitment manoeuvres did not induce barotrauma. Haemodynamic instability was not detected either in the maximum pressure step (overdistension step 5) or during the entire process. No substantial differences were observed in blood oxidative stress parameters analysed as compared with their baseline values (with 0 PEEP) or the values obtained 180 min after the onset of the recruitment manoeuvres (optimal PEEP). Significant maximal values were achieved in step 14 with an increase in paO2 (32.43 ±â€Š8.48 vs. 40.39 ±â€Š15.66 kPa; P = 0.037), Vt (47.75 ±â€Š13.59 vs. 73.87 ±â€Š13.56 ml; P = 0.006) and Cdyn (2.50 ±â€Š0.64 vs. 4.75 ±â€Š0.88 ml cmH2O; P < 0.001). Maximal dynamic compliance step (maxCdyn-PEEP) was 2 cmH2O. CONCLUSION: Recruitment manoeuvres in PCV with a constant driving pressure are a well tolerated open-lung strategy in a healthy-lung neonatal animal model under general anaesthesia. The recruitment manoeuvres improve oxygenation parameters and lung mechanics and do not cause barotrauma, haemodynamic instability or oxidative stress.

Use of Transesophageal Echocardiography During Orthotopic Liver Transplantation: Simplifying the Procedure.

The intraoperative management of patients undergoing orthotopic liver transplantation (OLT) is influenced by the cardiovascular manifestations typically found in the context of end-stage liver disease, by the presence of concomitant cardiovascular disease, and by the significant hemodynamic changes that occur during surgery. Hypotension and intraoperative blood pressure fluctuations during OLT are associated with liver graft dysfunction, acute kidney failure, and increased risk of 30-d mortality. Patients also frequently present hemodynamic instability due to various causes, including cardiac arrest. Recent evidence has shown transesophageal echocardiography (TEE) to be a useful minimally invasive monitoring tool in patients undergoing OLT that gives valuable real-time information on biventricular function and volume status and can help to detect OLT-specific complications or situations. TEE also facilitates rapid diagnosis of life-threatening conditions in each stage of OLT, which is difficult to identify with other types of monitoring commonly used. Although there is no consensus on the best approach to intraoperative monitoring in these patients, intraoperative TEE is safe and useful and should be recommended during OLT, according to experts, for assessing hemodynamic changes, identifying possible complications, and guiding treatment with fluids and inotropes to achieve optimal patient care.

Humanisation in paediatric intensive care units: A narrative review.

OBJECTIVE: To identify findings in the scientific literature relevant to the strategic lines proposed by the Humanising Intensive Care Project in the context of paediatric intensive care units. DESIGN: Narrative review. METHODS: A literature search was conducted in the databases PubMed, Scopus, CINHAL, and Cochrane Library. Specific indexing terms and search strategies adapted to each database were designed. The inclusion of publications was based on two criteria: 1) related to the paediatric intensive care unit and 2) addresses at least one of the topics related to the strategic lines of the Humanising Intensive Care Project. Study selection was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and the quality of the included studies was assessed using the Mixed Method Appraisal tool. RESULTS: A total of 100 articles from 19 different countries were included, covering the period between 2019 and 2021. Nineteen different design types were identified. Thirty-two studies were cross-sectional observational studies, while 15 had an experimental approach. The articles were distributed among the seven strategic lines of the Humanising Intensive Care Project. CONCLUSIONS: Synthesising the knowledge related to humanisation in paediatric intensive care units will allow progress to be made in improving quality in these units. However, there is disparity in the amount of experimental research overall. IMPLICATIONS FOR CLINICAL PRACTICE: There is a disparity in the available research related to the different strategic lines, and it is necessary to carry out more exhaustive research on topics such as the presence and participation of the family in care or the management of post-paediatric intensive care syndrome.

Multidisciplinary Consensus on the Management of Non-Invasive Respiratory Support in the COVID-19 Patient.

Acute respiratory failure due to COVID-19 pneumonia often requires a comprehensive approach that includes non-pharmacological strategies such as non-invasive support (including positive pressure modes, high flow therapy or awake proning) in addition to oxygen therapy, with the primary goal of avoiding endotracheal intubation. Clinical issues such as determining the optimal time to initiate non-invasive support, choosing the most appropriate modality (based not only on the acute clinical picture but also on comorbidities), establishing criteria for recognition of treatment failure and strategies to follow in this setting (including palliative care), or implementing de-escalation procedures when improvement occurs are of paramount importance in the ongoing management of severe COVID-19 cases. Organizational issues, such as the most appropriate setting for management and monitoring of the severe COVID-19 patient or protective measures to prevent virus spread to healthcare workers in the presence of aerosol-generating procedures, should also be considered. While many early clinical guidelines during the pandemic were based on previous experience with acute respiratory distress syndrome, the landscape has evolved since then. Today, we have a wealth of high-quality studies that support evidence-based recommendations to address these complex issues. This document, the result of a collaborative effort between four leading scientific societies (SEDAR, SEMES, SEMICYUC, SEPAR), draws on the experience of 25 experts in the field to synthesize knowledge to address pertinent clinical questions and refine the approach to patient care in the face of the challenges posed by severe COVID-19 infection.

Real-World Evidence of Off-Label Use of Commercially Automated Insulin Delivery Systems Compared to Multiple Daily Insulin Injections in Pregnancies Complicated by Type 1 Diabetes.

Aims: To compare glycemic control and maternal-fetal outcomes of women with type 1 diabetes (T1D) using hybrid closed loop (HCL) versus multiple daily insulin injections (MDI) plus continuous glucose monitoring. Methods: Multicenter prospective cohort study of pregnant women with T1D in Spain. We evaluated HbA1c and time spent within (TIR), below (TBR), and above (TAR) the pregnancy-specific glucose range of 3.5-7.8 mmol/L. Adjusted models were performed for adverse pregnancy outcomes, including baseline maternal characteristics and center. Results: One hundred twelve women were included (HCL n = 59). Women in the HCL group had a longer duration of diabetes and higher rates of prepregnancy care. There was no between-group difference in HbA1c in any trimester. However, in the second trimester, MDI users had a greater decrease in HbA1c (-6.12 ± 9.06 vs. -2.16 ± 7.42 mmol/mol, P = 0.031). No difference in TIR (3.5-7.8 mmol/L) and TAR was observed between HCL and MDI users, but with a higher total insulin dose in the second trimester [+0.13 IU/kg·day)]. HCL therapy was associated with increased maternal weight gain during pregnancy (ßadjusted = 3.20 kg, 95% confidence interval [CI] 0.90-5.50). Regarding neonatal outcomes, newborns of HCL users were more likely to have higher birthweight (ßadjusted = 279.0 g, 95% CI 39.5-518.5) and macrosomia (ORadjusted = 3.18, 95% CI 1.05-9.67) compared to MDI users. These associations disappeared when maternal weight gain or third trimester HbA1c was included in the models. Conclusions: In a real-world setting, HCL users gained more weight during pregnancy and had larger newborns than MDI users, while achieving similar glycemic control in terms of HbA1c and TIR.

Executive Summary of the Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR) Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management.

The Airway section of the Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) present the Guidelines for the integral management of difficult airway in adult patients. This document provides recommendations based on current scientific evidence, theoretical-educational tools and implementation tools, mainly cognitive aids, applicable to the treatment of the airway in the field of anesthesiology, critical care, emergencies and prehospital medicine. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations and optimization in the progression of the application of strategies to preserve adequate alveolar oxygenation in order to improve safety and quality of care.

Effects of naloxone on opioid-induced hyperalgesia and tolerance to remifentanil under sevoflurane anesthesia in rats.

BACKGROUND: Opioid antagonists at ultra-low doses have been used with opioid agonists to prevent or limit opioid tolerance. The aim of this study was to evaluate whether an ultra-low dose of naloxone combined with remifentanil could block opioid-induced hyperalgesia and tolerance under sevoflurane anesthesia in rats. METHODS: Male adult Wistar rats were allocated into one of four treatment groups (n = 7), receiving remifentanil (4 µg·kg·min) combined with naloxone (0.17 ng·kg·min), remifentanil alone, naloxone alone, or saline. Animals were evaluated for mechanical nociceptive thresholds (von Frey) and subsequently anesthetized with sevoflurane to determine the baseline minimum alveolar concentration (MAC). Next, treatments were administered, and the MAC was redetermined twice during the infusion. The experiment was performed three times on nonconsecutive days (0, 2, and 4). Hyperalgesia was considered to be a decrease in mechanical thresholds, whereas opioid tolerance was considered to be a decrease in sevoflurane MAC reduction by remifentanil. RESULTS: Remifentanil produced a significant decrease in mechanical thresholds compared with baseline values at days 2 and 4 (mean ± SD, 30.7 ± 5.5, 22.1 ± 6.4, and 20.7 ± 3.7g at days 0, 2, and 4, respectively) and an increase in MAC baseline values (2.5 ± 0.3, 3.0 ± 0.3, and 3.1 ± 0.3 vol% at days 0, 2, and 4, respectively). Both effects were blocked by naloxone coadministration. However, both remifentanil-treated groups (with or without naloxone) developed opioid tolerance determined by their decrease in MAC reduction. CONCLUSIONS: An ultra-low dose of naloxone blocked remifentanil-induced hyperalgesia but did not change opioid tolerance under inhalant anesthesia. Moreover, the MAC increase associated with hyperalgesia was also blocked by naloxone.

Pressure safety range of barotrauma with lung recruitment manoeuvres: a randomised experimental study in a healthy animal model.

CONTEXT: Recruitment manoeuvres aim at reversing atelectasis during general anaesthesia but are associated with potential risks such as barotrauma. OBJECTIVE: To explore the range of pressures that can be used safely to fully recruit the lung without causing barotrauma in an ex-vivo healthy lung rabbit model. DESIGN: Prospective, randomised, experimental study. SETTING: Experimental Unit, La Paz University Hospital, Madrid, Spain. ANIMALS: Fourteen healthy young New Zealand rabbits of 12 weeks of age. INTERVENTIONS: Animals were euthanised, the thorax and both pleural spaces were opened and the animals were allocated randomly into one of two groups submitted to two distinct recruitment manoeuvre strategies: PEEP-20 group, in which positive end-expiratory pressure (PEEP) was increased in 5-cmH2O steps from 0 to 20 cmH2O and PEEP-50 group, in which PEEP was increased in 5-cmH2O steps from 0 to 50 cmH2O. In both groups, a driving pressure of 15 cmH2O was maintained until maximal PEEP and its corresponding maximal inspiratory pressures (MIPs) were reached. From there on, driving pressure was progressively increased in 5-cmH2O steps until detectable barotrauma occurred. Two macroscopic conditions were defined: anatomically open lung and barotrauma. MAIN OUTCOME MEASURES: We measured open lung and barotrauma MIP, PEEP and driving pressure obtained using each strategy. A pressure safety range, defined as the difference between barotrauma MIP and anatomically open lung MIP, was also determined in both groups. RESULTS: Open lung MIP was similar in both groups: 23.6 ±â€Š3.8 and 23.3 ±â€Š4.1 cmH2O in the PEEP-50 and PEEP-20 groups, respectively (P = 0.91). However, barotrauma MIP in the PEEP-50 group was higher (65.7 ±â€Š3.4 cmH2O) than in the PEEP-20 group (56.7 ±â€Š5 0.2 cmH2O) (P = 0.003) resulting in a safety range of pressures of respectively 33.3 ±â€Š8.7 and 42.1 ±â€Š3.9 cmH2O (P = 0.035). CONCLUSION: In this ex-vivo model, we found a substantial difference between recruitment and barotrauma pressures using both recruitment strategies. However, a higher margin of safety was obtained when a higher PEEP and lower driving pressure strategy was used for recruiting the lung.

Shortened Automatic Lung Recruitment Maneuvers in an In Vivo Model of Neonatal ARDS.

BACKGROUND: The aim of this study was to assess the safety and efficacy of 2 protocols for automatic lung recruitment maneuvers (LRMs) using stepwise increases in PEEP in a neonatal ARDS model. These protocols were designed with lower maximum opening pressures than traditional methods and differ each one in the duration of the opening phases (short vs prolonged). We described hemodynamic changes through invasive monitoring, and we analyzed if the behavior of the variables depends on the duration of the opening phase of the LRM. METHODS: We designed a prospective, experimental study with 10 Landrace x Large White pigs < 48 h old. Under general anesthesia, tracheal intubation, invasive hemodynamic monitoring with a pediatric arterial thermodilution catheter was performed. An ARDS model was developed with bronchoalveolar lavages. Two types of LRMs were performed in each piglet, with a maximum peak inspiratory pressure (PIP) of 30 cm H2O and a PEEP 15 cm H2O applied during 8.5 s in the short LRM and 17 s in the prolonged LRM. A comparative analysis by virtue of the Wilcoxon signed-rank test and a regression analysis using generalized estimation equation were performed. RESULTS: We found that both LRMs were effective regarding oxygenation and respiratory mechanics. Shortening the duration of the opening phase and lowering the maximum opening pressures to PIP 30 and PEEP 15 cm H2O were above the critical opening pressure to reverse alveolar collapse in our neonatal ARDS model. Although we observed hemodynamic variations during both types of LRMs, these were well tolerated. CONCLUSIONS: Our LRM protocols exceeded critical opening pressures to reverse alveolar collapse in our neonatal ARDS model. This range of pressures might involve less hemodynamic disturbance. Duration of the maximum opening pressure step is a determining factor for hemodynamic alterations.

Impact of Stepwise Recruitment Maneuvers on Cerebral Hemodynamics: Experimental Study in Neonatal Model.

BACKGROUND: Lung recruitment maneuvers (LRMs) have been demonstrated to be effective in avoiding atelectasis during general anesthesia in the pediatric population. Performing these maneuvers is safe at the systemic hemodynamic and respiratory levels. AIMS: We aimed to evaluate the impact of a stepwise LRM and individualized positive end-expiratory pressure (PEEP) on cerebral hemodynamics in an experimental neonatal model. METHODS: Eleven newborn pigs (less than 72 h old, 2.56 ± 0.18 kg in weight) were included in the study. The LRM was performed under pressure-controlled ventilation with a constant driving pressure (15 cmH2O) in a stepwise increasing PEEP model. The target peak inspiratory pressure (PIP) was 30 cmH2O and the PEEP was 15 cmH2O. The following hemodynamic variables were monitored using the PICCO® system: mean arterial pressure (MAP), central venous pressure (CVP), and cardiac output (CO). The cerebral hemodynamics variables monitored were intracranial pressure (ICP) (with an intraparenchymal Camino® catheter) and cerebral oxygen saturation (rSO2) (with the oximetry monitor INVOS 5100® system). The following respiratory parameters were monitored: oxygen saturation, fraction of inspired oxygen, partial pressure of oxygen, end-tidal carbon dioxide pressure, Pmean, PEEP, static compliance (Cstat), and dynamic compliance (Cdyn). RESULTS: All LRMs were safely performed as scheduled without any interruptions. Systemic hemodynamic stability was maintained during the lung recruitment maneuver. No changes in ICP occurred. We observed an improvement in rSO2 after the maneuver (+5.8%). CONCLUSIONS: Stepwise LRMs are a safe tool to avoid atelectasis. We did not observe an impairment in cerebral hemodynamics but an improvement in cerebral oxygenation.

Clinical impact of del Nido cardioplegia in adult cardiac surgery: A prospective randomized trial.

OBJECTIVE: The study objective was to assess the benefits of del Nido cardioplegia compared with cold blood cardioplegia solution in terms of myocardial protection during adult cardiac surgery. METHODS: A total of 474 adult patients undergoing coronary artery bypass grafting, heart valve surgery, thoracic aortic surgery, or combined procedures were randomized to the del Nido cardioplegia group (n = 234) or the cold blood cardioplegia solution group (n = 240) after provided informed consent. The primary end points assessed inotropic support requirements, severe cardiovascular events, and troponin trend within the first 48 hours of intensive care unit stay. Reperfusion arrhythmias, aortic crossclamp and cardiopulmonary bypass times, and other clinical perioperative variables were considered as secondary end points. RESULTS: No statistically significant differences were found regarding postoperative inotropic support requirements or the incidence of severe cardiovascular events. The del Nido cardioplegia group showed a higher return to spontaneous sinus rhythm (P< .001), a lower number of defibrillation attempts (P< .001), and an earlier peak troponin value in the postoperative period. Peak blood glucose levels and intravenous insulin requirements were significantly lower in the del Nido cardioplegia group. We found no significant differences regarding aortic crossclamp or cardiopulmonary bypass time. We did observe a lower incidence of postoperative stroke in the del Nido cardioplegia group (2.6% vs 6.7%; P= .035). CONCLUSIONS: del Nido cardioplegia can be used safely and with comparable outcomes compared with traditional cardioplegia solutions. Additional advantages over glycemic control, reperfusion arrhythmias, and its comfortable redosing interval make del Nido an interesting alternative for myocardial protection in adult cardiac surgery. A significant decrease in postoperative stroke will require further research to shed light on the results of this study. VIDEO ABSTRACT.