Introduction
The analysis of heart rate variability (HRV) has proven to be an important tool for the management of autonomous nerve system in both surgical and critically ill patients. We conducted this study to show the different spectral frequency and time domain parameters of HRV as a prospective predictor for critically ill patients, and in particular for COVID-19 patients who are on mechanical ventilation. The hypothesis is that most severely ill COVID-19 patients have a depletion of the sympathetic nervous system and a predominance of parasympathetic activity reflecting the remaining compensatory anti-inflammatory response.
Materials and methods
A single-center, prospective, observational pilot study which included COVID-19 patients admitted to the Surgical Intensive Care Unit was conducted. The normalized high-frequency component (HFnu), i.e. ANIm, and the standard deviation of RR intervals (SDNN), i.e. Energy, were recorded using the analgesia nociception index monitor (ANI). To estimate the severity and mortality we used the SOFA score and the date of discharge or date of death.
Results
A total of fourteen patients were finally included in the study. ANIm were higher in the non-survivor group (p = 0.003) and were correlated with higher IL-6 levels (p = 0.020). Energy was inversely correlated with SOFA (p = 0.039) and fewer survival days (p = 0.046). A limit value at 80 of ANIm, predicted mortalities with a sensitivity of 100% and specificity of 85.7%. In the case of Energy, a limit value of 0.41 ms predicted mortality with all predictive values of 71.4%.
Conclusion
A low autonomic nervous system activity, i.e. low SDNN or Energy, and a predominance of the parasympathetic system, i.e. low HFnu or ANIm, due to the sympathetic depletion in COVID-19 patients are associated with a worse prognosis, higher mortality, and higher IL-6 levels.
Background: We aimed to examine whether using a high fraction of inspired oxygen (FIO 2 ) in the context of an individualised intra-and postoperative open-lung ventilation approach could decrease surgical site infection (SSI) in patients scheduled for abdominal surgery. Methods: We performed a multicentre, randomised controlled clinical trial in a network of 21 university hospitals from June 6, 2017 to July 19, 2018. Patients undergoing abdominal surgery were randomly assigned to receive a high (0.80) or conventional (0.3) FIO 2 during the intraoperative period and during the first 3 postoperative hours. All patients were mechanically ventilated with an open-lung strategy, which included recruitment manoeuvres and individualised positive end-expiratory pressure for the best respiratory-system compliance, and individualised continuous postoperative airway pressure for adequate peripheral oxyhaemoglobin saturation. The primary outcome was the prevalence of SSI within the first 7 postoperative days. The secondary outcomes were composites of systemic complications, length of intensive care and hospital stay, and 6-month mortality. Results: We enrolled 740 subjects: 371 in the high FIO 2 group and 369 in the low FIO 2 group. Data from 717 subjects were available for final analysis. The rate of SSI during the first postoperative week did not differ between high (8.9%) and low (9.4%) FIO 2 groups (relative risk [RR]: 0.94; 95% confidence interval [CI]: 0.59e1.50; P¼0.90]). Secondary outcomes, such as atelectasis (7.7% vs 9.8%; RR: 0.77; 95% CI: 0.48e1.25; P¼0.38) and myocardial ischaemia (0.6% [n¼2] vs 0% [n¼0]; P¼0.47) did not differ between groups. Conclusions: An oxygenation strategy using high FIO 2 compared with conventional FIO 2 did not reduce postoperative SSIs in abdominal surgery. No differences in secondary outcomes or adverse events were found. Clinical trial registration: NCT02776046.
Background
Arthroscopic shoulder surgery causes severe postoperative pain. An interscalene brachial plexus block provides adequate analgesia, but unintended spread of the local anesthetic administered may result in a phrenic nerve block, usually associated with a nonnegligible incidence of acute hemidiaphragmatic paralysis.
The main purpose of this trial will be to analyze the incidence of hemidiaphragmatic paralysis ensuing after interscalene brachial plexus block in patients undergoing arthroscopic shoulder surgery administered a standard volume (20 ml) vs. a low volume (10 ml) of levobupivacaine 0.25%.
Methods
This will be a prospective double-blind randomized controlled single-center two-arm comparative trial. Forty-eight patients will be included. The primary goal will be to ultrasonographically determine the incidence of hemidiaphragmatic paralysis by calculating the diaphragmatic thickness ratio in each group. The secondary goals will be to compare the two arms in terms of (1) decrease in forced vital capacity and (2) in forced expiratory volume at 1 s by spirometry; (3) decrease in diaphragmatic excursion by ultrasound; (4) 24-h total intravenous morphine consumption; (5) time to first opioid request of a patient-controlled analgesia pump; and (6) postoperative complications.
Discussion
This trial will demonstrate that a low-volume interscalene brachial plexus block decreases hemidiaphragmatic paralysis following arthroscopic shoulder surgery according to spirometry and ultrasound measurements and does not provide inferior postoperative analgesia to the standard volume, as measured by opioid requirements.
Trial registration
EudraCT and Spanish Trial Register (REec) registration number: 2019-003855-12 (registered on 7 January 2020). ClinicalTrials.gov identification number: NCT04385966 (retrospectively registered on 8 May 2020). Ethics Committee approval: EC19/093 (18 December 2019).
Summary
The interscalene brachial plexus block is recommended for analgesia after shoulder surgery but it may cause hemidiaphragmatic dysfunction. We tested whether ipsilateral hemidiaphragmatic contraction was better after a smaller dose of local anaesthetic without impairing analgesic effect. We randomly allocated 48 adults to 10 ml or 20 ml levobupivacaine 0.25% before arthroscopic shoulder surgery. The primary outcome was hemidiaphragmatic paralysis, defined as inspiratory thickness < 1.2 times expiratory thickness, measured by ultrasound 4 h after block. Hemidiaphragmatic paralysis was recorded for 6/24 vs. 23/24 supine participants after 10 ml vs. 20 ml levobupivacaine 0.25%, respectively, and for 4/24 vs. 23/24 sitting participants, respectively, p < 0.001 for both. Pain scores after 10 ml injectate were not worse than after 20 ml injectate. Median (IQR [range]) morphine doses in the first 24 postoperative hours after 10 ml and 20 ml levobupivacaine 0.25% were 2 (0–6 [0–23]) mg vs. 1 (0–2 [0–11]) mg, respectively, p = 0.12. No participant had a complication after 10 ml interscalene levobupivacaine, whereas seven had complications after 20 ml levobupivacaine, p = 0.009. Hemidiaphragmatic function was better after 10 ml vs. 20 ml interscalene levobupivacaine 0.25% without impairing analgesia for 24 postoperative hours.
Pulmonary complications continue to be the most common adverse event after surgery. The main objective was to carry out two independent predictive models, both for early pulmonary complications in the Post-Anesthesia Care Unit and late-onset pulmonary complications after 30 postoperative days. The secondary objective was to determine whether presenting early complications subsequently causes patients to have other late-onset events. This is a secondary analysis of a cohort study. 714 patients were divided into four groups depending on the neuromuscular blocking agent, and spontaneous or pharmacological reversal. Incidence of late-onset complications if we have not previously had any early complications was 4.96%. If the patient has previously had early complications the incidence of late-onset complications was 22.02%. If airway obstruction occurs, the risk of atelectasis increased from 6.88 to 22.58% (p = 0.002). If hypoxemia occurs, the incidence increased from 5.82 to 21.79% (p < 0.001). Based on our predictive models, we conclude that diabetes mellitus and preoperative anemia are two risk factors for early and late-onset postoperative pulmonary complications, respectively. Hypoxemia and airway obstruction in Post-Anesthesia Care Unit increased four times the risk of the development of pneumonia and atelectasis at 30 postoperative days.
The purpose of this study is to demonstrate that the most critically ill patients with COVID-19 have greater autonomic nervous system dysregulation and assessing the heart rate variability, allows us to predict severity and 30-day mortality. This was a multicentre, prospective, cohort study. Patients were divided into two groups depending on the 30-day mortality. The heart rate variability and more specifically the relative parasympathetic activity (ANIm), and the SDNN (Energy), were measured. To predict severity and mortality multivariate analyses of ANIm, Energy, SOFA score, and RASS scales were conducted. 112 patients were collected, the survival group (n = 55) and the deceased group (n = 57). The ANIm value was higher (p = 0.013) and the Energy was lower in the deceased group (p = 0.001); Higher Energy was correlated with higher survival days (p = 0.009), and a limit value of 0.31 s predicted mortalities with a sensitivity of 71.9% and a specificity of 74.5%. Autonomic nervous system and heart rate variability monitoring in critically ill patients with COVID-19 allows for predicting survival days and 30-day mortality through the Energy value. Those patients with greater severity and mortality showed higher sympathetic depletion with a predominance of relative parasympathetic activity.
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