Changes in the sublingual microcirculation following aortic surgery under balanced or total intravenous anaesthesia: a prospective observational study

The impact of magnesium on shivering incidence in cardiac surgery patients: A systematic review

Background and objective

This scientific review involves a sequential analysis of randomized trial research focused on the incidence of shivering in patients undergoing cardiac surgery. The study conducted a comprehensive search of different databases, up to the end of 2020. Only randomized trials comparing magnesium administration with either placebo or no treatment in patients expected to experience shivering were included. The primary objective was to evaluate shivering occurrence, distinguishing between patients receiving general anesthesia and those not. Secondary outcomes included serum magnesium concentrations, intubation time, post-anesthesia care unit stay, hospitalization duration, and side effects. Data collection included patient demographics and various factors related to magnesium administration.

Material and methods

This scientific review analyzed 64 clinical trials meeting inclusion criteria, encompassing a total of 4303 patients. Magnesium was administered via different routes, primarily intravenous, epidural, and intraperitoneal, and compared against placebo or control. Data included demographics, magnesium dosage, administration method, and outcomes. Heterogeneity was assessed using the I2 statistic. Some studies were excluded due to unavailability of data or non-responsiveness from authors.

Result

and discussion: Out of 2546 initially identified articles, 64 trials were selected for analysis. IV magnesium effectively reduced shivering, with epidural and intraperitoneal routes showing even greater efficacy. IV magnesium demonstrated cost-effectiveness and a favorable safety profile, not increasing adverse effects. The exact dose-response relationship of magnesium remains unclear. The results also indicated no significant impact on sedation, extubation time, or gastrointestinal distress. However, further research is needed to determine the optimal magnesium dose and to explore its potential effects on blood pressure and heart rate, particularly regarding pruritus prevention.

Conclusion

This study highlights the efficacy of intravenous (IV) magnesium in preventing shivering after cardiac surgery. Both epidural and intraperitoneal routes have shown promising results. The safety profile of magnesium administration appears favorable, as it reduces the incidence of shivering without significantly increasing costs. However, further investigation is required to establish the ideal magnesium dosage and explore its potential effects on blood pressure, heart rate, and pruritus prevention, especially in various patient groups.

Ultrasound-guided quadratus lumborum block: Posterior versus anterior approach in paediatrics undergoing laparoscopic inguinal hernia repair

Background and Aims

Regional anaesthesia has gained popularity in managing post-operative pain in paediatric patients. Quadratus lumborum block (QLB) is recognised as one of the peri-operative pain management techniques used during abdominal surgeries. However, no consensus about the best approach has been reached.

Material and Methods

Sixty paediatric patients with ages ranging from 1 to 6 as well as classification I and II of the American Society of Anesthesiologists, scheduled for laparoscopic inguinal hernia, were allocated to receive either a posterior approach (Group I) or an anterior approach (Group II) QLB. Twenty four-hour morphine consumption, the face, legs, activity, cry, and consolability (FLACC) score, duration of analgesia, performance time, and block-related complications were recorded.

Results

Group II showed significantly lower morphine consumption as well as a longer duration of analgesia (P = 0.039*, 0.020*, respectively), with an equivalent period for block performance being reported in the two groups (P = 0.080). At 2, 4, 6, and 12 hours post-operatively, the FLACC scores were substantially diminished in Group II compared to Group I (P = 0.001*, 0.012*, 0.002*, 0.028*, respectively). However, at twenty-four hours, comparable pain scores were observed between both groups (P = 0.626). In addition, there were no block-related complications.

Conclusions

In paediatric patients scheduled for laparoscopic inguinal hernia repair, the ultra-sound-guided anterior approach of the QLB was associated with significantly reduced post-operative morphine consumption, a lower FLACC score, and a longer analgesia duration when compared to the posterior approach.

Microcirculatory Alterations in Cardiac Surgery: A Comprehensive Guide

Microcirculation is essential for cellular life and its functions. It comprises a complex network of capillaries, arterioles, and venules, which distributes oxygenated blood across and within organs based on regional metabolic demands. Because previous research indicated that organ function is linked to microcirculatory function, it is crucial to maintain sufficient and effective microcirculatory function during major surgery. Impaired microcirculation can lead to inadequate tissue perfusion, potentially resulting in perioperative complications and an unfavorable outcome. Indeed, changes in microcirculation in cardiovascular disease and cardiac surgery have a direct correlation with prolonged stays in the postoperative intensive care unit and high mortality rates within 30 days. Additionally, cardiopulmonary bypass, a regularly employed method in cardiac surgery, has been proven to induce microcirculatory malfunction and, thus, lead to postoperative multiple organ dysfunction. As global hemodynamic parameters can remain stable or improve, whereas microcirculation is still compromised, tracking microcirculatory variables could lead to the development of targeted microcirculatory treatment within hemodynamic management. Therefore, it is necessary to enhance the use of microcirculatory monitoring in the medical domain to assist physicians in the therapeutic management of patients undergoing cardiac surgery. This potentially can lead to better hemodynamic management and outcomes. This review article concentrates on the use of handheld video microscopes for real-time microcirculatory assessment of cardiac surgery patients in the immediate and early postoperative period. Emphasis is placed on integrating microcirculatory monitoring with conventional hemodynamic monitoring in the therapeutic management of patients undergoing cardiac surgery.

Intraoperative individualization of positive-end-expiratory pressure through electrical impedance tomography or esophageal pressure assessment: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

This systematic review of randomized-controlled trials (RCTs) with meta-analyses aimed to compare the effects on intraoperative arterial oxygen tension to inspired oxygen fraction ratio (PaO2/FiO2), exerted by positive end-expiratory pressure (PEEP) individualized trough electrical impedance tomography (EIT) or esophageal pressure (Pes) assessment (intervention) vs. PEEP not tailored on EIT or Pes (control), in patients undergoing abdominal or pelvic surgery with an open or laparoscopic/robotic approach.

METHODS

PUBMED®, EMBASE®, and Cochrane Controlled Clinical trials register were searched for observational studies and RCTs from inception to the end of August 2022. Inclusion criteria were: RCTs comparing PEEP titrated on EIT/Pes assessment vs. PEEP not individualized on EIT/Pes and reporting intraoperative PaO2/FiO2. Two authors independently extracted data from the enrolled investigations. Data are reported as mean difference and 95% confidence interval (CI).

RESULTS

Six RCTs were included for a total of 240 patients undergoing general anesthesia for surgery, of whom 117 subjects in the intervention group and 123 subjects in the control group. The intraoperative mean PaO2/FiO2 was 69.6 (95%CI 32.-106.4 ) mmHg higher in the intervention group as compared with the control group with 81.4% between-study heterogeneity (p < 0.01). However, at meta-regression, the between-study heterogeneity diminished to 44.96% when data were moderated for body mass index (estimate 3.45, 95%CI 0.78-6.11, p = 0.011).

CONCLUSIONS

In patients undergoing abdominal or pelvic surgery with an open or laparoscopic/robotic approach, PEEP personalized by EIT or Pes allowed the achievement of a better intraoperative oxygenation compared to PEEP not individualized through EIT or Pes.

PROSPERO REGISTRATION NUMBER

CRD 42021218306, 30/01/2023.

A pre-anesthetic bolus of ketamine versus dexmedetomidine for prevention of postoperative delirium in elderly patients undergoing emergency surgery: a randomized, double-blinded, placebo-controlled study

BACKGROUND

We aimed to evaluate whether a single dose of ketamine or dexmedetomidine before induction of general anesthesia could reduce the incidence of postoperative delirium (primary outcome) or cognitive dysfunction (secondary outcome) in elderly patients undergoing emergency surgery.

PATIENTS AND METHODS

This randomized, double-blinded, placebo-controlled trial included 60 elderly patients who were scheduled for emergency surgery. The patients were randomly assigned into one of three groups (n = 20): group I received 0.9% normal saline, group II received 1 µg/kg dexmedetomidine, and group III received 1 mg/kg ketamine right before anesthesia induction. Patients were observed for three days after surgery and tested for postoperative delirium and cognitive dysfunction using the delirium observation screening scale and the mini-mental state examination score, respectively.

RESULTS

The dexmedetomidine group had the lowest incidence of delirium (p = 0.001) and cognitive dysfunction (p = 0.006) compared to the ketamine and placebo groups. The multivariate logistic regression model revealed that dexmedetomidine reduced the incidence of postoperative delirium by 32% compared to placebo (reference) (OR = 0.684, 95% CI: 0.240-0.971, p = 0.025), whereas ketamine increased the risk by threefold (OR = 3.012, 95% CI: 1.185-9.681, p = 0.013). Furthermore, dexmedetomidine reduced the incidence of postoperative cognitive dysfunction by 62% (OR = 0.375, 95% CI: 0.091-0.543, p = 0.012), whereas ketamine increased the risk by 4.5 times (OR = 4.501, 95% CI: 1.161-8.817, p = 0.006).

CONCLUSION

A single pre-anesthetic bolus of dexmedetomidine is a practical choice for preventing postoperative delirium in elderly patients undergoing emergency surgery.

TRIAL REGISTRATION

This study was approved by the Ethics Committee of Aswan University Hospital (approval number: aswu/548/7/2021; registration date: 06/07/2021) and registered on ClinicalTrials.gov (NCT05341154) (22/04/2022).

Risk Factors and Early Outcomes for Gastrointestinal Complications in Patients Undergoing Open Surgery for Type A Aortic Dissection

BACKGROUND

Gastrointestinal complications need to be paid more attention, especially in critically ill patients. The purpose of this study was to identify the risk factors and short-term outcomes of gastrointestinal complications after open surgery for type A aortic dissection.

METHODS

A retrospective single-institutional study including patients who underwent open surgery for type A aortic dissection during 2012-2020 was conducted. Univariate analysis and logistic regression analysis were used to identify risk factors associated with gastrointestinal complications. The related clinical outcomes were compared between the patients with and without gastrointestinal complications.

RESULTS

Among the 2746 patients, 150 developed gastrointestinal complications. The development of gastrointestinal complications contributed to the higher rate of mortality (P = .008), longer stay in the intensive care unit (P < .001), and longer hospital stay (P < .001). Logistic regression analysis showed that age (odds ratio [OR] 1.020; 95% confidence interval [CI] 1.005-1.057; P = .011), American Society of Anesthesiologists classification greater than grade III (OR 1.724; 95%CI 1.179-2.521, P = .005), pre-induction mean arterial pressure (OR 0.978; 95%CI 0.965-0.990, P = .001), aortic cross-clamp time (OR 1.012; 95%CI 1.005-1.019, P = .001), cardiopulmonary bypass time (OR 1.007; 95%CI 1.002-1.011, P = .002), and intraoperative transfusion of red blood cells (OR 1.214; 95%CI 1.122-1.314, P = .001) were independent risk factors for gastrointestinal complications.

CONCLUSIONS

The incidence of gastrointestinal complications after open surgery for type A aortic dissection was 5.5%, resulting in increased mortality and prolonged hospital stay. It is necessary to take suitable strategies to reduce the incidence of gastrointestinal complications.

Microcirculatory Monitoring in Children with Congenital Heart Disease Before and After Cardiac Surgery

In this prospective observational study, we investigated whether congenital heart disease (CHD) affects the microcirculation and whether the microcirculation is altered following cardiac surgery with cardiopulmonary bypass (CPB). Thirty-eight children with CHD undergoing cardiac surgery with CPB and 35 children undergoing elective, non-cardiac surgery were included. Repeated non-invasive sublingual microcirculatory measurements were performed with handheld vital microscopy. Before surgery, children with CHD showed similar perfused vessel densities and red blood cell velocities (RBCv) but less perfused vessels (p < 0.001), lower perfusion quality (p < 0.001), and higher small vessel densities (p = 0.039) than children without CHD. After cardiac surgery, perfused vessel densities and perfusion quality of small vessels declined (p = 0.025 and p = 0.032), while RBCv increased (p = 0.032). We demonstrated that CHD was associated with decreased microcirculatory perfusion and increased capillary recruitment. The microcirculation was further impaired after cardiac surgery. Decreased microcirculatory perfusion could be a warning sign for altered tissue oxygenation and requires further exploration.

Incidence change of postoperative delirium after implementation of processed electroencephalography monitoring during surgery: a retrospective evaluation study

BACKGROUND

Postoperative delirium (POD) is a common complication in the elderly, which is associated with poor outcomes after surgery. Recognized as predisposing factors for POD, anesthetic exposure and burst suppression during general anesthesia can be minimized with intraoperative processed electroencephalography (pEEG) monitoring. In this study, we aimed to evaluate whether implementation of intraoperative pEEG-guided anesthesia is associated with incidence change of POD.

METHODS

In this retrospective evaluation study, we analyzed intravenous patient-controlled analgesia (IVPCA) dataset from 2013 to 2017. There were 7425 patients using IVPCA after a noncardiac procedure under general anesthesia. Patients incapable of operating the device independently, such as cognitive dysfunction or prolonged sedation, were declined and not involved in the dataset. After excluding patients who opted out within three days (N = 110) and those with missing data (N = 24), 7318 eligible participants were enrolled. Intraoperative pEEG has been implemented since July 2015. Participants having surgery after this time point had intraoperative pEEG applied before induction until full recovery. All related staff had been trained in the application of pEEG-guided anesthesia and the assessment of POD. Patients were screened twice daily for POD within 3 days after surgery by staff in the pain management team. In the first part of this study, we compared the incidence of POD and its trend from 2013 January-2015 July with 2015 July-2017 December. In the second part, we estimated odds ratios of risk factors for POD using multivariable logistic regression in case-control setting.

RESULTS

The incidence of POD decreased from 1.18 to 0.41% after the administration of intraoperative pEEG. For the age group ≧ 75 years, POD incidence decreased from 5.1 to 1.56%. Further analysis showed that patients with pEEG-guided anesthesia were associated with a lower odd of POD (aOR 0.33; 95% CI 0.18-0.60) than those without after adjusting for other covariates.

CONCLUSIONS

Implementation of intraoperative pEEG was associated with a lower incidence of POD within 3 days after surgery, particularly in the elderly. Intraoperative pEEG might be reasonably considered as part of the strategy to prevent POD in the elder population.

TRIAL REGISTRATION

Not applicable.

Synthesis, biological evaluation and computer-aided discovery of new thiazolidine-2,4-dione derivatives as potential antitumor VEGFR-2 inhibitors

In this study, novel VEGFR-2-targeting thiazolidine-2,4-dione derivatives with potential anticancer properties were designed and synthesized. The ability of the designed derivatives to inhibit VEGFR-2 and stop the growth of three different cancer cell types (HT-29, A-549, and HCT-116) was examined in vitro. The IC50 value of compound 15, 0.081 μM, demonstrated the best anti-VEGFR-2 potency. Additionally, compound 15 showed remarkable anti-proliferative activities against the tested cancer cell lines, with IC50 values ranging from 13.56 to 17.8 μM. Additional flow cytometric investigations showed that compound 15 increased apoptosis in HT-29 cancer cells (from 3.1% to 31.4%) arresting their growth in the S phase. Furthermore, compound 15's apoptosis induction in the same cell line was confirmed by increasing the levels of BAX (4.8-fold) and decreasing Bcl-2 (2.8-fold). Also, compound 15 noticeably increased caspase-8 and caspase-9 levels by 1.7 and 3.2-fold, respectively. Computational methods were used to perform molecular analysis of the VEGFR-2-15 complex. Molecular dynamics simulations and molecular docking were utilized to analyze the complex's kinetic and structural characteristics. Protein-ligand interaction profiler analysis (PLIP) determined the 3D interactions and binding conformation of the VEGFR-2-15 complex. DFT analyses also provided insights into the 3D geometry, reactivity, and electronic characteristics of compound 15. Computational ADMET and toxicity experiments were conducted to determine the potential of the synthesized compounds for therapeutic development. The study's findings suggest that compound 15 might be an effective anticancer lead compound and could guide future attempts to develop new drugs.

Association of Early Serum Phosphate Levels and Mortality in Patients with Sepsis

BACKGROUND

Metabolic derangements in sepsis influence phosphate levels, which may predict mortality outcomes. We investigated the association between initial phosphate levels and 28-day mortality in patients with sepsis.

METHODS

We conducted a retrospective analysis of patients with sepsis. Initial (first 24 hours) phosphate levels were divided into phosphate quartile groups for comparisons. We used repeated-measures mixed-models to assess differences in 28-day mortality across the phosphate groups, adjusting for other predictors identified by the Least Absolute Shrinkage and Selection Operator variable selection technique.

RESULTS

A total of 1,855 patients were included with 13% overall 28-day mortality (n=237). The highest phosphate quartile (>4.0 milligrams per deciliter [mg/dL]) had a higher mortality rate (28%) than the three lower quartiles (P<0.001). After adjustment (age, organ failure, vasopressor administration, liver disease), the highest initial phosphate was associated with increased odds of 28-day mortality. Patients in the highest phosphate quartile had 2.4 times higher odds of death than the lowest (≤2.6 mg/dL) quartile (P<0.01), 2.6 times higher than the second (2.6-3.2 mg/dL) quartile (P<0.01), and 2.0 times higher than the third (3.2-4.0 mg/dL) quartile (P=0.04).

CONCLUSION

Septic patients with the highest phosphate levels had increased odds of mortality. Hyperphosphatemia may be an early indicator of disease severity and risk of adverse outcomes from sepsis.

Prospective paired crossover evaluation of potential impact of investigator gender on perceived pain intensity early after acute or scheduled surgery

BACKGROUND

Postoperative pain is common but often difficult to assess, and there are many potential confounders. Over the last decades, the gender of investigator as well as participant has been found to influence pain perception in both preclinical and clinical studies. However, to our knowledge this has not been studied in various postoperative patients. Objectives of this study were to test the hypotheses that pain intensity levels early after acute or scheduled in- or out-hospital surgery are lower when evaluated by a female investigator, and higher when reported by a female patient.

METHODS

In this prospective observational paired crossover study, two investigators of opposite genders independently obtained individually reported pain intensity levels with a visual analogue scale in a mixed cohort of adult postoperative study patients at Skåne University Hospital in Malmö, Sweden.

RESULTS

In total, 245 (129 female) study patients were included and then one female excluded. The study patients rated their intensity of postoperative pain lower when evaluated by a female than by a male investigator (P = 0.006), where the male patients constituted the significant difference (P < 0.001). Pain intensity levels did not differ between female and male study patients (P = 0.210).

CONCLUSIONS

Main findings of lower pain intensity reported by males to a female than to a male investigator early after surgery in this paired crossover study in mixed postoperative patients, indicate that potential impact of investigator gender on pain perception should be considered and further evaluated in clinical bedside practice. Trial registration Retrospectively registered in the ClinicalTrials.gov research database on 24th June 2019 with TRN number NCT03968497.

Identifying a sublingual triangle as the ideal site for assessment of sublingual microcirculation

The sublingual mucosa is a commonly used intraoral location for identifying microcirculatory alterations using handheld vital microscopes (HVMs). The anatomic description of the sublingual cave and its related training have not been adequately introduced. The aim of this study was to introduce anatomy guided sublingual microcirculatory assessment. Measurements were acquired from the floor of the mouth using incident dark-field (IDF) imaging before (T0) and after (T1) sublingual cave anatomy instructed training. Instructions consists of examining a specific region of interested identified through observable anatomical structures adjacent and bilaterally to the lingual frenulum which is next to the sublingual papilla. The anatomical location called the sublingual triangle, was identified as stationed between the lingual frenulum, the sublingual fold and ventrally to the tongue. Small, large, and total vessel density datasets (SVD, LVD and TVD respectively) obtained by non-instructed and instructed measurements (NIN (T0) and IM (T1) respectively) were compared. Microvascular structures were analyzed, and the presence of salivary duct-related microcirculation was identified. A total of 72 video clips were used for analysis in which TVD, but not LVD and SVD, was higher in IM compared to NIM (NIM vs. IM, 25 ± 2 vs. 27 ± 3 mm/mm2 (p = 0.044), LVD NIM vs. IM: 7 ± 1 vs. 8 ± 1mm/mm2 (p = 0.092), SVD NIM vs. IM: 18 ± 2 vs. 20 ± 3 mm/mm2 (p = 0.103)). IM resulted in microcirculatory assessments which included morphological properties such as capillaries, venules and arterioles, without salivary duct-associated microcirculation. The sublingual triangle identified in this study showed consistent network-based microcirculation, without interference from microcirculation associated with specialized anatomic structures. These findings suggest that the sublingual triangle, an anatomy guided location, yielded sublingual based measurements that conforms with international guidelines. IM showed higher TVD values, and future studies are needed with larger sample sizes to prove differences in microcirculatory parameters.

Relationship between serum phosphate and mortality in critically ill children receiving continuous renal replacement therapy

Purpose

We aimed to explore the relationship between serum phosphate concentration and 90-day mortality in critically ill children receiving continuous renal replacement therapy (CRRT).

Methods

Data from the medical records of children aged <13 years who received CRRT at the Pediatric Intensive Care Unit of Hunan Children's Hospital, China from January 2015 to June 2020 were retrospectively collected. Children were grouped into four categories according to the baseline phosphate concentration before CRRT and mean serum phosphate concentration during CRRT: <0.81 mmol/L (hypophosphatemia), 0.81-1.19 mmol/L, 1.2-2.4 mmol/L (normal phosphate concentration), and >2.4 mmol/L (hyperphosphatemia), with the normal phosphate group serving as the comparator group. The correlation of the serum phosphate concentration before and during CRRT with the 90-day mortality after CRRT initiation was analyzed using logistic regression.

Results

A total of 177 children were included in our study. The mean serum phosphate concentration before CRRT was 1.46 mmol/L (quartiles: 1.04, 2.20). The 90-day mortality rate was increased in children with a serum phosphate concentration >2.4 mmol/L before CRRT (adjusted odds ratio [aOR] 3.74, 95% confidence interval [CI] 1.42-9.86, P = 0.008). The mean serum phosphate concentration during CRRT was 1.2 mmol/L (quartiles: 0.91, 1.49). The 90-day mortality rate was increased in children with a mean serum phosphate concentration >2.4 mmol/L during CRRT (aOR 7.34, 95% CI 1.59-33.88, P = 0.011).

Conclusion

Hyperphosphatemia before and during CRRT predicts a higher 90-day mortality rate.

Effect of sevoflurane versus propofol on neutrophil-to-lymphocyte ratio in healthy individuals: a sub-study of a randomised crossover trial

Background

Sevoflurane and propofol are commonly used drugs in general anaesthesia. However, their effects on perioperative immune function are incompletely understood. We hypothesised that sevoflurane and propofol differentially affect immune function in healthy individuals. Therefore, we investigated the effect of sevoflurane and propofol on neutrophil-to-lymphocyte ratio before, during, and after general anaesthesia.

Methods

In this randomised crossover study, 19 healthy individuals underwent 2 h of general anaesthesia with either propofol or sevoflurane. After 4 weeks, anaesthesia was repeated using the other drug. Blood samples were obtained before, during, 1 h after, and 1 day after anaesthesia. The primary outcome was whole-blood neutrophil-to-lymphocyte ratio, and secondary outcomes were specific white blood cell differential counts. A linear mixed-effects model was used to estimate effect sizes.

Results

The neutrophil-to-lymphocyte ratio was higher in the propofol compared with the sevoflurane group during anaesthesia, 2.8 (confidence interval [CI]: 2.3-3.3) vs 1.6 (CI: 1.1-2.1), and 1 day after anaesthesia, 2.6 (CI: 2.1-3.1) vs 1.9 (CI: 1.4-2.4). In all patients, we observed transient lymphopaenia during propofol anaesthesia, 1.1 × 109 cells × L-1 (CI: 0.9-1.4), compared with sevoflurane anaesthesia, 1.9 × 109 cells × L-1 (CI: 1.7-2.1). In addition, neutrophil counts were higher 1 day after propofol anaesthesia, 4.4 × 109 cells × L-1 (CI: 4.0-4.9), compared with sevoflurane anaesthesia, 3.5 × 109 cells × L-1 (CI: 3.1-4.0). We observed no differences in the remaining white blood cell subgroups.

Conclusions

In healthy individuals undergoing general anaesthesia without surgery, the neutrophil-to-lymphocyte ratio was affected by the type of hypnotic used. Transient lymphopaenia was observed in all participants during propofol anaesthesia.

The use of a vascular occlusion test combined with near-infrared spectroscopy in perioperative care: a systematic review

In the perioperative phase oxygen delivery and consumption can be influenced by different factors, i.e. type of surgery, anesthetic and cardiovascular drugs, or fluids. By combining near-infrared spectroscopy (NIRS) monitoring of regional tissue oxygen saturation (StO₂) with an ischemic provocation test, the vascular occlusion test (VOT), local tissue oxygen consumption and vascular reactivity at the microcirculatory level can be assessed. This systematic review aims to give an overview of the clinical information that VOT-derived NIRS values can provide in the perioperative period. After performing a systematic literature search, we included 29 articles. It was not possible to perform a meta-analysis because of the lack of comparable data and the observational nature of the majority of the included articles. We have clustered the found articles in two groups: non-cardiac surgery and cardiac surgery. We found that VOT-derived NIRS values show a wide variability and are influenced by the effects of anesthetics, cardiovascular drugs, fluids, and by the type of surgery. Additionally, deviations in VOT-derived NIRS values are also associated with adverse patients' outcomes, such as postoperative complications, prolonged mechanical ventilation and prolonged hospital length of stay. However, given the variability in VOT-derived NIRS values, clinical applicability remains elusive. Future clinical interventional trials might provide additional insight into the potential of VOT associated with NIRS to optimize perioperative care by targeting specific interventions to optimize the function of the microvasculature.

The use of pulse pressure variation for predicting impairment of microcirculatory blood flow

Dynamic parameters of preload have been widely recommended to guide fluid therapy based on the principle of fluid responsiveness and with regard to cardiac output. An equally important aspect is however to also avoid volume-overload. This accounts particularly when capillary leakage is present and volume-overload will promote impairment of microcirculatory blood flow. The aim of this study was to evaluate, whether an impairment of intestinal microcirculation caused by volume-load potentially can be predicted using pulse pressure variation in an experimental model of ischemia/reperfusion injury. The study was designed as a prospective explorative large animal pilot study. The study was performed in 8 anesthetized domestic pigs (German landrace). Ischemia/reperfusion was induced during aortic surgery. 6 h after ischemia/reperfusion-injury measurements were performed during 4 consecutive volume-loading-steps, each consisting of 6 ml kg⁻¹ bodyweight⁻¹. Mean microcirculatory blood flow (mean Flux) of the ileum was measured using direct laser-speckle-contrast-imaging. Receiver operating characteristic analysis was performed to determine the ability of pulse pressure variation to predict a decrease in microcirculation. A reduction of ≥ 10% mean Flux was considered a relevant decrease. After ischemia–reperfusion, volume-loading-steps led to a significant increase of cardiac output as well as mean arterial pressure, while pulse pressure variation and mean Flux were significantly reduced (Pairwise comparison ischemia/reperfusion-injury vs. volume loading step no. 4): cardiac output (l min⁻¹) 1.68 (1.02–2.35) versus 2.84 (2.15–3.53), p = 0.002, mean arterial pressure (mmHg) 29.89 (21.65–38.12) versus 52.34 (43.55–61.14), p < 0.001, pulse pressure variation (%) 24.84 (17.45–32.22) versus 9.59 (1.68–17.49), p = 0.004, mean Flux (p.u.) 414.95 (295.18–534.72) versus 327.21 (206.95–447.48), p = 0.006. Receiver operating characteristic analysis revealed an area under the curve of 0.88 (CI 95% 0.73–1.00; p value < 0.001) for pulse pressure variation for predicting a decrease of microcirculatory blood flow. The results of our study show that pulse pressure variation does have the potential to predict decreases of intestinal microcirculatory blood flow due to volume-load after ischemia/reperfusion-injury. This should encourage further translational research and might help to prevent microcirculatory impairment due to excessive fluid resuscitation and to guide fluid therapy in the future.

Association between serosal intestinal microcirculation and blood pressure during major abdominal surgery

Background

In clinical practice, blood pressure is used as a resuscitation goal on a daily basis, with the aim of maintaining adequate perfusion and oxygen delivery to target organs. Compromised perfusion is often indicated as a key factor in the pathophysiology of anastomotic leakage. This study was aimed at assessing the extent to which the microcirculation of the bowel coheres with blood pressure during abdominal surgery.

Methods

We performed a prospective and observational cohort study. In patients undergoing abdominal surgery, the serosal microcirculation of either the small intestine or the colon was visualized using handheld vital microscopy (HVM). From the acquired HVM image sequences, red blood cell velocity (RBCv) and total vessel density (TVD) were calculated using MicroTools and AVA software, respectively. The association between microcirculatory parameters and blood pressure was assessed using Pearson's correlation analysis. We considered a two-sided P-value of <0.050 to be significant.

Results

In 28 patients undergoing abdominal surgery, a total of 76 HVM images were analyzed. The RBCv was 335 ± 96 µm/s and the TVD was 13.7 ± 3.4 mm/mm². Mean arterial pressure (MAP) was 71 ± 12 mm Hg during microcirculatory imaging. MAP was not correlated with RBCv (Pearson's r = -0.049, P = 0.800) or TVD (Pearson's r = 0.310, P = 0.110).

Conclusion

In 28 patients undergoing abdominal surgery, we found no association between serosal intestinal microcirculatory parameters and blood pressure.

Effects of anesthetics on microvascular reactivity measured by vascular occlusion tests during off-pump coronary artery bypass surgery: a randomized controlled trial

Microvascular function may be modulated by various anesthetics. Desflurane and propofol anesthesia have different effects on microvascular function. However, there are few reports on the effects of sevoflurane and desflurane on microvascular function during cardiac surgery. We compared the effects of sevoflurane and desflurane on microvascular reactivity, as measured by the vascular occlusion tests (VOTs) during off-pump coronary artery bypass (OPCAB) surgery. Patients undergoing OPCAB were eligible for study inclusion. Patients were excluded if they were unsuitable for treatment with volatile agents or the VOT, had renal failure or uncontrolled diabetes, or were pregnant. The enrolled patients were randomized to receive sevoflurane or desflurane during surgery. Tissue oxygen saturation (StO₂) dynamics during the VOT were measured at baseline (pre-anesthesia), pre-anastomosis, post-anastomosis of vessel grafts, and at the end of surgery. Macrohemodynamic variables, arterial blood gas parameters, and in-hospital adverse events were also evaluated. A total of 64 patients (32 in each group) were analyzed. StO₂ dynamics did not differ between the groups. Compared to baseline, StO₂ and the rate of recovery following vascular occlusion decreased at the end of surgery in both groups (adjusted p-value, < 0.001), and no group difference was observed. Macrohemodynamic variables, blood gas analysis results, and the rate of postoperative in-hospital adverse events were similar between the groups. Microvascular reactivity, as measured by the VOT during OPCAB, showed no difference between the sevoflurane and desflurane groups. Also, there were no group differences in macrohemodynamics or the rate of postoperative adverse events. TRIAL REGISTRATION : Clinicaltrials.gov, identifier NCT03209193; registered on July 3, 2017.

Is hospitalisation a risk factor for cognitive decline in the elderly?

PURPOSE OF REVIEW

Cognitive decline is frequently reported after hospitalisation in the contexts of surgery, delirium and critical care. The question not adequately addressed is whether all types of acute hospitalisations increase the risk of cognitive decline. As acute hospitalisations are common in the elderly, who are also vulnerable to cognitive decline, this possible association is of significant concern.

RECENT FINDINGS

This review summarises cognitive outcomes from recent observational studies investigating acute hospitalisation (emergent and elective) in older age adults. Studies were identified from searching Medline, Embase and PsycINFO databases and citations lists. The highest incidence of cognitive decline has been reported following critical care admissions and admissions complicated by delirium, although all types of acute hospitalisations are implicated. Age is the most consistent risk factor for cognitive decline. Several etiological and therapeutic aspects are being investigated, particularly the measurement of inflammatory biomarkers and treatment with anti-inflammatory medications.

SUMMARY

Acute hospitalisation for any reason appears to increase the risk of cognitive decline in older adults, but the cause remains elusive. Future research must clarify the nature and modifiers of posthospitalisation cognitive change, a priority in the face of an ageing population.