Microcirculatory changes during open label magnesium sulphate infusion in patients with severe sepsis and septic shock

<p>Abstract</p> <p>Background</p> <p>Microcirculatory alterations play a pivotal role in sepsis and persist despite correction of systemic hemodynamic parameters. Therefore it seems tempting to test specific pro-microcirculatory strategies, including vasodilators, to attenuate impaired organ perfusion. As opposed to nitric oxide donors, magnesium has both endothelium-dependent and non-endothelium-dependent vasodilatory pathways.</p> <p>Methods</p> <p>In a single-center open label study we evaluated the effects of magnesium sulphate (MgS) infusion on the sublingual microcirculation perfusion in fluid resuscitated patients with severe sepsis and septic shock within the first 48 hours after ICU admission. Directly prior to and after 1 hour of magnesium sulphate (MgS) infusion (2 gram) systemic hemodynamic variables, sublingual SDF images and standard laboratory tests, were obtained.</p> <p>Results</p> <p>Fourteen patients (12 septic shock, 2 severe sepsis) with a median APACHE II score of 20 were enrolled. No significant difference of the systemic hemodynamic variables was found between baseline and after MgS infusion. We did not observe any significant difference pre and post MgS infusion in the primary endpoint microvascular flow index (MFI) of small vessels: 2.25(1.98-2.69) vs. 2.33(1.96-2.62), p = 0.65. Other variables of microcirculatory perfusion were also unaltered. In the overall unchanged microvascular perfusion there was a non-significant trend to an inverse linear relationship between the changes of MFI and its baseline value (y = -0.7260 × + 1.629, r²= 0.270, p = 0.057). The correlation between baseline Mg concentrations and the change in MFI pre- and post MgS infusion was non-significant (r_s= -0.165, p = 0.67).</p> <p>Conclusions</p> <p>In the setting of severe sepsis and septic shock sublingual microcirculatory alterations were observed despite fulfillment of sepsis resuscitation guidelines. After infusion of a limited and fixed dose of MgS, microcirculatory perfusion did not improve over time.</p> <p>Trial registration</p> <p>ClinicalTrials.gov NTC01332734.</p

Laparoscopic Laser Speckle Contrast Imaging Can Visualize Anastomotic Perfusion:A Demonstration in a Porcine Model

Background: Intestinal resection causes inevitable vascular damage, which cannot always be seen during an intraoperative clinical assessment of local intestinal perfusion. If left unaltered, impaired perfusion can lead to complications, such as anastomotic leakage (AL). Therefore, we demonstrate the use of a novel laparoscopic laser speckle contrast imaging (LSCI)-based approach in order to assess local intestinal perfusion during the construction of intestinal anastomoses. Methods: Three segments were isolated from the small intestine of a pig, while the perfusion of each was compromised by coagulating 7–8 mesenteric arteries. Both clinical assessments and LSCI were used to detect the induced perfusion deficits and to subsequently guide a transection in either a well perfused, marginally perfused, or poorly perfused tissue area within the segment. Bowel ends were then utilized for the creation of three differently perfused anastomoses: well perfused/well perfused (anastomosis segment 1), well perfused/poorly perfused (anastomosis segment 2), and poorly perfused/poorly perfused (anastomosis segment 3). After construction of the anastomoses, a final perfusion assessment using both clinical assessment and LSCI was executed in order to evaluate the vascular viability of the anastomosis. Results: Laparoscopic LSCI enabled continuous assessment of local intestinal perfusion and allowed for detection of perfusion deficits in real time. The imaging feedback precisely guided the surgical procedure, and, when evaluating the final anastomotic perfusion, LSCI was able to visualize the varying degrees of perfusion, whereas standard clinical assessment yielded only minor differences in visual appearance of the tissue. Conclusions: In this technical note, we demonstrate a novel LSCI-based approach for intraoperative perfusion assessment. With its ability to continuously visualize perfusion in real time, laparoscopic LSCI has significant potential for the optimization of anastomotic surgery in the near future

The Reduction in Right Ventricular Longitudinal Contraction Parameters Is Not Accompanied by a Reduction in General Right Ventricular Performance During Aortic Valve Replacement:An Explorative Study

Objective: The aim of the present study was to identify whether the decrease of longitudinal parameters after cardiothoracic surgery (ie, tricuspid annular systolic plane excursion [TAPSE] and systolic excursion velocity [S']) is accompanied by a reduction in global right ventricular (RV) performance. Design: Prospective, observational study. Setting: Single-center explorative study in a tertiary teaching hospital. Participants: The study comprised 20 patients who underwent aortic valve replacement with or without coronary artery bypass grafting. Interventions: During cardiac surgery, simultaneous measurements of RV function were performed with a pulmonary artery catheter and transesophageal echocardiography. Measurements and Main Results: TAPSE and S’ were reduced significantly directly after surgery compared with the time before surgery (TAPSE from 20.8 [16.6-23.4] mm to 9.1 [5.6-15.5] mm; p < 0.001 and S’ from 8.7 [7.9-10.7] cm/s to 7.2 [5.7-8.6] cm/s; p = 0.041). However, the reduction in TAPSE and S’ was not accompanied by a reduction in RV performance, as assessed with the TEE-derived myocardial performance index (MPI) and pulmonary artery catheter–derived RV ejection fraction (RVEF). Both remained statistically unaltered before and after the procedure (MPI from 0.52 [0.43-0.58] to 0.50 [0.42-0.88]; p = 0.278 and RVEF from 27% [22%-32%] to 26% [22%-28%]; p = 0.294). Conclusions: In the direct postoperative phase, the reduction of echocardiographic parameters of longitudinal RV contractility (TAPSE and S’) were not accompanied by a reduction in global RV performance, expressed as MPI and RVEF. Solely relying on a single RV parameter as a marker for global RV performance may not be adequate to assess the complex adaptation of the right ventricle to aortic valve replacement

Application of laser speckle contrast imaging in laparoscopic surgery

Anastomotic leakage is a worldwide problem in gastrointestinal surgery which seems to be related to the state of microcirculation. Laser speckle contrast imaging (LSCI) could give surgeons insight in the state of microcirculation to attune the site of anastomosis. This work studies the feasibility of LSCI as a tool for this purpose. An experimental setup was developed using a commercially available laparoscopic video system. Laser speckle contrast imaging is capable of detecting ischemic areas on the large intestine. Further research and development are required before adaptation of this technique in the operating room

Long-term health-related quality of life, healthcare utilisation and back-to-work activities in intensive care unit survivors:Prospective confirmatory study from the Frisian aftercare cohort

PURPOSE: More substantial information on recovery after Intensive Care Unit (ICU) admission is urgently needed. In a previous retrospective study, the proportion of non-recovery patients was 44%. The aim of this prospective follow-up study was to evaluate changes in Health-Related Quality of Life (HRQoL) in the first year after ICU-admission. METHODS: Long-stay adult ICU-patients (≥ 48 hours) were included. HRQoL was evaluated with the Dutch translation of the RAND-36 item Health Survey (RAND-36) at baseline via proxy measurement, and at three, six, and twelve months after ICU admission. Subsequently, the relation between physical functioning, healthcare utilisation, and work activities was explored. RESULTS: A total of 81 patients were included in this study. Fifty-five percent of patients did not meet criteria for full recovery and were allocated to the Non Recovery (NR)-group (Physical Functioning domain-score: 35 [15-55]). Baseline physical HRQoL differed significantly between the Recovery (R) and NR-group. Patients in the NR-group received home care more often and had higher healthcare utilisation (44 versus 17% in the first three months post-ICU, p = 0.013). Only fourteen percent of NR-patients were able to participate in work activities. Moreover, NR-patients persistently showed impaired overall HRQoL throughout the year after critical illness. CONCLUSIONS: Limited recovery in ICU survivors is reflected in overall impaired HRQoL, as well as in far-reaching consequences for patients' healthcare needs and their ability to reintegrate into society. In our study, baseline HRQoL appeared to be an important predictor of long-term outcomes, but not Clinical Frailty Scale (CFS) score. And, (proxy-derived) HRQoL may help to identify patients at risk of long-term non-recovery

Effects of ketanserin on microcirculatory alterations in septic shock:An open-label pilot study

INTRODUCTION: Microcirculatory alterations in sepsis are associated with increased morbidity and mortality. These alterations occur despite macrohemodynamic resuscitation. Alternative pro-microcirculatory strategies, including vasodilatory drugs, have been suggested to improve capillary blood flow. Ketanserin, a serotonin receptor antagonist, is an attractive candidate because of its vasodilatory, antithrombotic, and anti-inflammatory effects. METHODS: This is an open-label pilot study on the effect of ketanserin administration on microcirculatory alterations in septic shock, defined as microvascular flow index (MFI) ≤ 2.5 after a strict macrohemodynamic resuscitation protocol. Sidestream dark-field imaging was applied to assess the microcirculation. A stepwise incremental dose regiment was applied until an MFI > 2.9, the primary end point, was reached. RESULTS: Ten patients (Acute Physiology and Chronic Health Evaluation IV scores of 115 [100-136]) were included. Baseline MFI was 1.71 (1.31-2.32) and was significantly increasing to 2.96 (2.54-3.00; P = .021) during the ketanserin infusion. The total ketanserin dose was 0.09 (0.08-0.13) mg/kg per patient in 60 (30-60) minutes. In 3 patients (30%), the ketanserin infusion was discontinued due to refractory hypotension. CONCLUSION: An improvement in microcirculatory perfusion was observed during ketanserin administration in patients with septic shock after macrohemodynamic resuscitation. This finding needs further exploration in a placebo-controlled setting

Real-time visualization of renal microperfusion using laser speckle contrast imaging

Significance: Intraoperative parameters of renal cortical microperfusion (RCM) have been associated with postoperative ischemia/reperfusion injury. Laser speckle contrast imaging (LSCI) could provide valuable information in this regard with the advantage over the current standard of care of being a non-contact and full-field imaging technique. Aim: Our study aims to validate the use of LSCI for the visualization of RCM on ex vivo perfused human-sized porcine kidneys in various models of hemodynamic changes. Approach: A comparison was made between three renal perfusion measures: LSCI, the total arterial renal blood flow (RBF), and sidestream dark-field (SDF) imaging in different settings of ischemia/reperfusion. Results: LSCI showed a good correlation with RBF for the reperfusion experiment (0.94 +/- 0.02; p < 0.0001) and short- and long-lasting local ischemia (0.90 +/- 0.03; p < 0.0001 and 0.81 +/- 0.08; p < 0.0001, respectively). The correlation decreased for low flow situations due to RBF redistribution. The correlation between LSCI and SDF (0.81 +/- 0.10; p < 0.0001) showed superiority over RBF (0.54 +/- 0.22; p < 0.0001). Conclusions: LSCI is capable of imaging RCM with high spatial and temporal resolutions. It can instantaneously detect local perfusion deficits, which is not possible with the current standard of care. Further development of LSCI in transplant surgery could help with clinical decision making. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License

Real-time, multi-spectral motion artefact correction and compensation for laser speckle contrast imaging

Abstract Laser speckle contrast imaging (LSCI) is so sensitive to motion that it can measure the movement of red blood cells. However, this extreme sensitivity to motion is also its pitfall as the clinical translation of LSCI is slowed down due to the inability to deal with motion artefacts. In this paper we study the effectiveness of a real-time, multi-spectral motion artefact correction and compensation by subduing an in vitro flow phantom and ex vivo porcine kidney to computer-controlled motion artefacts. On the in vitro flow phantom, the optical flow showed a good correlation with the total movement. This model results in a better signal-to-noise ratios for multiple imaging distances and the overestimation of perfusion was reduced. In the ex vivo kidney model, the perfusion overestimation was also reduced and we were still able to distinguish between ischemia and non-ischemia in the stabilized data whereas this was not possible in the non-stabilized data. This leads to a notably better perfusion estimation that could open the door to a multitude of new clinical applications for LSCI