Clinical application of vascular occlusion test based on tissue oxygen saturation monitoring

The vascular occlusion test (VOT) is an experiment that simulates the process of distal ischemia-reperfusion of tissue based on the monitoring of tissue oxygen saturation (StO2) to obtain VOT parameters related to StO2 changes to evaluate microcirculation function of the measured muscle tissue. VOT has the advantages of real-time, noninvasive and continuous, and is widely used to evaluate the functional status of peripheral microcirculation and the relationship between microcirculation changes and prognosis of patients. In clinical work, doctors mainly focus on hemodynamics of patients, while microcirculation function is often neglected due to the lack of real-time monitoring methods, which may lead to severe poor prognosis of patients, especially patients with critical illness. This paper focuses on the clinical application of vascular occlusion test based on tissue oxygen saturation monitoring.

Application value of dexmedetomidine in anesthesia for elderly patients undergoing radical colon cancer surgery

BACKGROUND Colon cancer presents a substantial risk to the well-being of elderly people worldwide.With advancements in medical technology,surgical treatment has become the primary approach for managing colon cancer patients.However,due to age-related physiological changes,especially a decline in cognitive function,older patients are more susceptible to the effects of surgery and anesthesia,increasing the relative risk of postoperative cognitive dysfunction(POCD).There-fore,in the surgical treatment of elderly patients with colon cancer,it is of pa-ramount importance to select an appropriate anesthetic approach to reduce the occurrence of POCD,protect brain function,and improve surgical success rates.METHODS One hundred and seventeen patients with colon cancer who underwent elective surgery under general anesthesia were selected and divided into two groups:A and B.Group A received Dex before anesthesia induction,and B group received an equivalent amount of normal saline.Changes in the mini-mental state exami-nation,regional cerebral oxygen saturation(rSO2),bispectral index,glucose uptake rate(GluER),lactate production rate(LacPR),serum S100βand neuron-specific enolase(NSE),POCD,and adverse anesthesia reactions were compared between the two groups.RESULTS Surgical duration,duration of anesthesia,and intraoperative blood loss were comparable between the two groups(P>0.05).The overall dosage of anesthetic drugs used in group A,including propofol and remifentanil,was significantly lower than that used in group B(P<0.05).Group A exhibited higher rSO2 values at the time of endotracheal intubation,30 min after the start of surgery,and immediately after extubation,higher GluER values and lower LacPR values at the time of endotra-cheal intubation,30 min after the start of surgery,immediately after extubation,and 5 min after extubation(P<0.05).Group A exhibited lower levels of serum S100βand NSE 24 h postoperatively and a lower incidence of cognitive dysfunction on the 1st and 5th postoperative days(P<0.05).CONCLUSION The use of Dex in elderly patients undergoing radical colon cancer surgery helps maintain rSO2 Levels and reduce cerebral metabolic levels and the incidence of anesthesia-and surgery-induced cognitive dysfunction.

Factors associating with oxygenation of lower-limb muscle tissue in hemodialysis patients

AIM To evaluate the lower-limb muscle oxygenation in hemodialysis(HD) patients and identify the factors associating with muscle oxygenation.METHODS Sixty-seven HD patients(53 men and 14 women; mean age, 67.1 ± 1.2 years; mean HD duration, 5.6 ± 0.9 years) were recruited. In addition, 15 healthy individuals(nine men and six women; mean age, 38.2 ± 4.6 years) were recruited as the control group. Lower-limb muscle regional saturation of oxygen(rS O_2) was monitored on the lateral side of the gastrocnemius muscle before HD using an INVOS 5100C(Covidien Japan, Tokyo, Japan), which utilizes near-infrared spectroscopy. Here, we evaluated the association between lower-limb muscle rS O_2 and clinical parameters.RESULTS The r SO_2 values were significantly lower in patients undergoing HD than in healthy individuals(50.0%± 1.7% vs 76.8% ± 2.5%, P < 0.001). Lower-limb muscle r SO_2 showed significant positive correlations with diastolic blood pressure, blood urea nitrogen concentration, serum creatinine concentration, serum potassium concentration, serum inorganic phosphate concentration, and serum albumin concentration as well as negative correlation with HD duration. We conducted a multiple linear regression analysis using parameters that were significantly correlated with the lower-limb muscle r SO_2 in a simple linear regression analysis. Multiple regression analysis demonstrated that lowerlimb muscle r SO_2 was independently associated with serum inorganic phosphate(standardized coefficient: 0.27) and serum albumin concentrations(standardized coefficient: 0.24). In addition, there were no differences in lower-limb muscle r SO_2 between diabetic and nondiabetic HD patients. This study has several limitations. Firstly, its sample size was relatively small. Secondly, we could not evaluate the association between lowerlimb muscle r SO_2 and calculated nutritional markers, including normalized protein catabolic rate and body mass index, anthropometric measurements representing nutritional status, and the severity of protein-energy wasting. Finally, we did not routinely examine the arterial vascular status of HD patients without symptoms of peripheral artery disease. As such, it is possible that some HD patients with subclinical peripheral artery disease may have been included in this study.CONCLUSION In HD patients, the oxygenation of lower-limb muscle tissue was associated with serum inorganic phosphate and albumin concentrations, both of which represent nutritional status.

Investigation of one-lung ventilation postoperative cognitive dysfunction and regional cerebral oxygen saturation relations

Objective： To explore the relationship of postoperative cognitive dysfunction （POCD） in one-lung ventilation （OLV） patients and regional cerebral oxygen saturation （rSO2）. Methods： Twenty-nine male and twenty-one female cases of OLV received thoracic surgery, with American Standards Association （ASA） physical status being at Grades Ⅰ-Ⅲ. Neuropsychological tests were performed on the day before operation and 7 d after operation, and there was an intraoperative continuous monitoring of rSO2. The values of rSO2 before anesthesia induction （t1）, at the beginning of OLV （t2）, and at the time of OLV 30 min （t3）, OLV 60 min （t4）, the end of OLV （t5）, and the end of surgery （t6） were recorded. The intraoperative average of rSO2 （ rSO2 ）, the intraoperative minimum value of rSO2 （rSO2, rn=n）, and the reduced maximum percentage of rSO2 （rSO2, %max） when compared with the baseline value were calculated. The volume of blood loss, urine output, and the amount of fluid infusion was recorded. Results： A total of 14 patients （28%） in the 50 cases suffered from POCD. The values of mini-mental state examination （MMSE）, the digit span and the digit symbol on the 7th day after the operation for POCD in OLV patients were found to be significantly lower than those before the operation （P〈0.05）. The values of MMSE and vocabulary fluency scores were significantly lower than those in the non-POCD group （P〈0.05）. The values of rSO2 in the POCD group of OLV patients at t2 and t3 and the values of rSO2 in the non-POCD group at t2 were found to be significantly higher than those at tl （P〈0.05）. The values of rSO2, %max in the POCD group were significantly higher than those in the non-POCD group （P〈0.05）. When the value of rSO2, %max is more than 10.1%, it may act as an early warning index for cognitive function changes, Conclusions： POCD after OLV may be associated with a decline in rSO2.

Relationship between post-operative cognitive dysfunction and regional cerebral oxygen saturation and β-amyloid protein

Objective： To investigate the relationship between post-operative cognitive dysfunction（POCD） and regional cerebral oxygen saturation（rSO2） and β-amyloid protein（Aβ） in patients undergoing laparoscopic pancreaticoduodenectomy. Methods： Fifty patients undergoing elective laparoscopic pancreaticoduodenectomy received five groups of neuropsychological tests 1 d pre-operatively and 7 d post-operatively, with continuous monitoring of rSO2 intra-operatively. Before anesthesia induction（t0）, at the beginning of laparoscopy（t1）, and at the time of pneumoperitoneum 120 min（t2）, pneumoperitoneum 240 min（t3）, pneumoperitoneum 480 min（t4）, the end of pneumoperitoneum（t5）, and 24 h after surgery, jugular venous blood was drawn respectively for the measurement of Aβ by enzyme-linked immunosorbent assay（ELISA）. Results： Twenty-one cases of the fifty patients suffered from POCD after operation. We found that the maximum percentage drop in rSO2（rSO2, %max） was significantly higher in the POCD group than in the non-POCD group. The rSO2, %max value of over 10.2% might be a potential predictor of neurocognitive injury for those patients. In the POCD group, the plasma Aβ levels after 24 h were significantly higher than those of pre-operative values（P〈0.01）. After 24 h, levels of plasma Aβ in the POCD group were significantly higher than those in the non-POCD group（P〈0.01）. Conclusions： The development of POCD in patients undergoing laparoscopic pancreaticoduodenectomy is associated with alterations of rSO2 and Aβ. Monitoring of rSO2 might be useful in the prediction of POCD, and Aβ might be used as a sensitive biochemical marker to predict the occurrence of POCD.

Effects of white noise on procedural pain-related cortical response and pain score in neonates:A randomized controlled trial

Objectives To evaluate the effects of white noise on pain-related cortical response,pain score,and behavioral and physiological parameters in neonates with procedural pain.Methods A double-blind,randomized controlled trial was conducted.Sixty-six neonates from the Neonatal Intensive Care Unit in a university-affiliated general hospital were randomly assigned to listen to white noise at 50 dB(experimental group)or 0 dB(control group)2 min before radial artery blood sampling and continued until 5 min after needle withdrawal.Pain-related cortical response was measured by regional cerebral oxygen saturation(rScO_(2))monitored with near-infrared spectroscopy,and facial expressions and physiological parameters were recorded by two video cameras.Two assessors scored the Premature Infant Pain Profile-Revised(PIPP-R)independently when viewing the videos.Primary outcomes were pain score and rScO_(2)during arterial puncture and 5 min after needle withdrawal.Secondary outcomes were pulse oximetric oxygen saturation(SpO_(2))and heart rate(HR)during arterial puncture,and duration of painful expressions.The study was registered at the Chinese Clinical Trial Registry(ChiCTR2200055571).Results Sixty neonates(experimental group,n=29;control group,n=31)were included in the final analysis.The maximum PIPP-R score in the experimental and control groups was 12.00(9.50,13.00),12.50(10.50,13.75),respectively(median difference−0.5,95%CI−2.0 to 0.5),and minimum rScO_(2)was(61.22±3.07)%,(61.32±2.79)%,respectively(mean difference−0.325,95%CI−1.382 to 0.732),without significant differences.During arterial puncture,the mean rScO_(2),HR,and SpO_(2)did not differ between groups.After needle withdrawal,the trends for rScO_(2),PIPP-R score,and facial expression returning to baseline were different between the two groups without statistical significance.Conclusion The white noise intervention did not show beneficial effects on pain-related cortical response as well as pain score,behavioral and physiological parameters in neonates with procedural pain.

Cerebral autoregulation-directed optimal blood pressure management reduced the risk of delirium in patients with septic shock

Background When resuscitating patients with septic shock,cerebrovascular reactivity parameters are calculated by monitoring regional cerebral oxygen saturation(rSO_(2))using near-infrared spectroscopy to determine the optimal blood pressure.Here,we aimed to analyze the impact of cerebral autoregulation-directed optimal blood pressure management on the incidence of delirium and the prognosis of patients with septic shock.Methods This prospective randomized controlled clinical study was conducted in the Xiangya Hospital of Central South University,China.Fifty-one patients with septic shock(December 2020–May 2022)were enrolled and randomly allocated to the experimental(n=26)or control group(n=25).Using the ICM+software,we monitored the dynamic changes in rSO_(2) and mean arterial pressure(MAP)and calculated the cerebrovascular reactivity parameter tissue oxygen reactivity index to determine the optimal blood pressure to maintain normal cerebral autoregulation function during resuscitation in the experimental group.The control group was treated according to the Surviving Sepsis Campaign Guidelines.Differences in the incidence of delirium and 28-day mortality between the two groups were compared,and the risk factors were analyzed.Results The 51 patients,including 39 male and 12 female,had a mean age of(57.0±14.9)years.The incidence of delirium was 40.1%(23/51),and the 28-day mortality rate was 29.4%(15/51).The mean MAP during the first 24 h of intensive care unit(ICU)admission was higher([84.5±12.2]mmHg vs.[77.4±11.8]mmHg,P=0.040),and the incidence of delirium was lower(30.8%vs.60.0%,P=0.036)in the experimental group than in the control group.The use of cerebral autoregulation-directed optimal blood pressure(odds ratio[OR]=0.090,95%confidence interval[CI]:0.009 to 0.923,P=0.043)and length of ICU stay(OR=1.473,95%CI:1.093 to 1.985,P=0.011)were risk factors for delirium during septic shock.Vasoactive drug dose(OR=8.445,95%CI:1.26 to 56.576,P=0.028)and partial pressure of oxygen(PaO_(2))(OR=0.958,95%CI:0.921 to 0.996,P=0.032)were the risk factors for 28-day mortality.Conclusions The use of cerebral autoregulation-directed optimal blood pressure management during shock resuscitation reduces the incidence of delirium in patients with septic shock.