Effects of pH management during deep hypothermic bypass on cerebral oxygenation： alpha-stat versus pH-stat

Objective: There is a remarkable lack of scientific evidence to support the option to use alpha-stat or pH-stat management, as to which is more beneficial to brain protection during deep hypothermic CPB. This study examined cortical blood flow (CBF), cerebral oxygenation, and brain oxygen consumption in relation to deep hypothermic CPB with alpha-stat or pH-stat management. Methods: Twenty-two pigs were cooled with alpha-stat or pH-stat during CPB to 15℃ esophageal temperature. CBF and cerebral oxygenation were measured continuously with a laser flowmeter and near-infrared spec-troscopy, respectively. Brain oxygen consumption was measured with standard laboratory techniques. Results: During CPB cooling, CBF was significantly decreased, about 52,2%±6.3% (P<0.01 vs 92.6%±6.5% of pH-stat) at 15℃ in alpha-stat, whereas there were no significant changes in CBF in pH-stat. While cooling down, brain oxygen extraction (OER) progressively decreased, about 9.5%±0.9% and 10.9%±1.5% at 15℃ in alpha-stat and pH-stat, respectively. At 31℃ the decreased value in pH-stat was lower than in alpha-stat (29.9%±2.7% vs 22.5%±1.9%; P<0.05). The ratio of CBF/OER were 2.0±0.3 in alpha-stat and pH-stat, respectively; it was kept in constant level in alpha-stat, and significantly increased by 19 ℃ to 15℃ in pH-stat (4.9±0.9 vs 2.3±0.4; P<0.01). In mild hypothermia, cerebral oxyhemoglobin and oxygen saturation in alpha-stat were greater than that in pH-stat (102.5%±1.4% vs 99.1%±0.7%; P<0.05). In deep hypothermia, brain oxygen saturation in pH-stat was greater than that in alpha-stat (99.2%±1.0% vs 93.8%±1.0%; P<0.01), and deoxyhemoglobin in pH-stat decreased more greatly than that in alpha-stat (28.7%±6.8% vs 54.1%±4.7%; P<0.05). Conclusions: In mild hypothermic CPB, brain tissue oxygen saturation was greater in alpha-stat than in pH-stat. However, cerebral oxygenation and brain tissue oxygen saturation were better in pH-stat than in alpha-stat during profound hypothermia. PH-stat strategy provided much more oxygen to brain tissue before deep hypothermic circulatory arrest.

Assessment of cerebral oxygenation response to hemodialysis using near-infrared spectroscopy (NIRS):Challenges and solutions

To date,the clinical use of functional near-infrared spectroscopy(NIRS)to detect cerebral ischemia has been largely limited to surgical settings,where motion artifacts are minimal.In this study,we present novel techniques to address the challenges of using NIRS to monitor ambu-latory patients with kidney disease during approximately eight hours of hemodialysis(HD)treatment.People with end-stage kidney disease who require HD are at higher risk for cognitive impairment and dementia than age-matched controls.Recent studies have suggested that HD-related declines in cerebral blood flow might explain some of the adverse outcomes of HD treatment.However,there are currently no established paradigms for monitoring cerebral per-fusion in real-time during HD treatment.In this study,we used NIRS to assess cerebral hemo-dynamic responses among 95 prevalent HD patients during two consecutive HD treatments.We observed substantial signal attenuation in our predominantly Black patient cohort that required probe modifications.We also observed consistent motion artifacts that we addressed by devel-oping a novel NIRS methodology,called the HD cerebral oxygen demand algorithm(HD-CODA),to identify episodes when cerebral oxygen demand might be outpacing supply during HD treatment.We then examined the association between a summary measure of time spent in cerebral deoxygenation,derived using the HD-CODA,and hemodynamic and treatment-related variables.We found that this summary measure was associated with intradialytic mean arterial pressure,heart rate,and volume removal.Future studies should use the HD-CODA to implement studies of real-time NIRS monitoring for incident dialysis patients,over longer time frames,and in other dialysis modalities.

Hypotension prediction index together with cerebral oxygenation in guiding intraoperative hemodynamic management: a case report

Intraoperative hypotension happens in everyday clinical practice. It was suggested to have a strong association with adverse postoperative outcomes. Hypotension prediction index(HPI) was developed to predict intraoperative hypotension(mean arterial pressure <65 mmHg) in real time. However, pressure autoregulation also plays an important role in maintaining adequate organ perfusion/oxygenation during hypotension. A cerebral oxygenation monitor provides clinicians with the values of organ oxygenation. We reported a case that the cerebral oxygenation monitor was used together with HPI to guide intraoperative blood pressure management. We found that cerebral oxygenation was maintained in the event of hypotension during surgery. The patient had no intraoperative or postoperative adverse outcomes despite the hypotension. We believe this can provide an individualized intraoperative blood pressure management to avoid over-or under-treating hypotension.

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.

Neuroprotection of hyperbaric oxygen therapy in sub-acute traumatic brain injury:not by immediately improving cerebral oxygen saturation and oxygen partial pressure

Although hyperbaric oxygen （HBO） therapy can promote the recovery of neural function in patients who have suffered traumatic brain injury （TBI）, the underlying mechanism is unclear. We hypothesized that hyperbaric oxygen treatment plays a neuroprotective role in TBI by increasing regional transcranial oxygen saturation （rSO2） and oxygen partial pressure （PaO2）. To test this idea, we compared two groups： a control group with 20 healthy people and a treatment group with 40 TBI patients. The 40 patients were given 100% oxygen of HBO for 90 minutes. Changes in rSO2 were measured. The controls were also examined for rSO2 and PaO2, but received no treatment, rSO2 levels in the patients did not differ significantly after treatment, but levels before and after treatment were significantly lower than those in the control group. PaO2 levels were significantly decreased after the 30-minute HBO treatment. Our findings suggest that there is a disorder of oxygen metabolism in patients with sub-acute TBI. HBO does not immediately affect cerebral oxygen metabolism, and the underlying mechanism still needs to be studied in depth.

Effect of Hemodilution on Fluctuation of Cerebral Oxygen Saturation during Cardiopulmonary Bypass in Children with Cyanotic Congenital Heart Disease

Background:In patients with cyanotic congenital heart disease(CHD),cerebral oxygenation may be maintained by elevations in hematocrit(Hct).Hemodilution accompanying cardiopulmonary bypass(CPB),however,can disrupt cerebral oxygen balance,leading to fluctuations in cerebral oxygen saturation(ScO_(2)).The present study investigated the effects of Hct changes on the fluctuation of ScO_(2)during CPB in cyanotic CHD using performance measurement(PM).Methods:Children with CHD(51 acyanotic and 46 cyanotic)who had undergone cardiac surgery using CPB were enrolled.Median performance error(MDPE),median absolute performance error(MDAPE),and wobble parameters of ScO_(2)were calculated before(reference value),during,and after CPB.Correlations of PM parameters with Hct and reductions in Hct(ΔHct)were also evaluated.Results:Before CPB,patients with cyanotic CHD had lower MDPE and larger wobble than those with acyanotic CHD,although mean ScO_(2)did not differ significantly between the two groups.During CPB,ScO_(2)of acyanotic CHD increased asΔHct increased,but PM variables were not associated withΔHct.In cyanotic CHD,MDPE(r=−0.324,p=0.032)and MDAPE(r=0.339,p=0.024)correlated significantly withΔHct during CPB.After CPB,MDPE(r=0.574,p=0.025)and MDAPE(r=−0.543,p=0.036)were significantly correlated with Hct in children with cyanotic CHD who underwent palliative surgery.Conclusion:Therefore,ScO_(2)fluctuation during CPB in children with cyanotic CHD may be affected by the decrease in Hct,suggesting that excessive hemodilution can negatively influence the maintenance of cerebral oxygenation in these patients.

Effect of hypertensive reperfusion on the changes between cerebral oxygen delivery and uptake after cardiac arrest and resuscitation in dogs

Objective: To study the changes between cerebral oxygen (O 2) delivery and uptake in dogs resuscitated under normotension or hypertension for 4 h. Methods: The model of ventricular fibrillation of 8 min in 12 dogs was made, followed by open cardiopulmonary resuscitation, reperfusion with normal or high mean arterial pressure (MAP), and controlled ventilation to 4 h. Animals were randomly assigned into Group NT (normotensive reperfusion, n=6) and Group HT (hypertensive reperfusion, n=6). Cerebral arteriovenous (sagittal sinus) O 2 content difference (Ca-ssO 2) and venous (sagittal sinus) PO 2 (PssO 2) were determined before cardiac arrest (CA) and 30, 60, 120, and 240 min after CA. Results: In Group NT, Ca-ssO 2 was lower at 30 min (P<0.05) but higher at 240 min (P<0.01) after CA than that before CA. In Group HT, Ca-ssO 2 was not significantly different from that in Group NT before CA but was lower than that in Group NT at 30 min after CA (P<0.01). Ca-ssO 2 was not significantly different in Group NT and HT thereafter. In both groups, PssO 2 was both higher at 30 min after reperfusion (P<0.01) and at 240 min after reperfusion lower (P<0.05) than those before CA .At 30 min after reperfusion, PssO 2 was higher (P<0.01) in Group HT than that in Group NT, with insignificant difference between two groups. Conclusion: Cerebral O 2 delivery and uptake are mismatched after CA and resuscitation. Hypertensive reperfusion improves oxygen delivery to the brain early after CA.

Effects of various anesthetic techniques and PaCO_2 levels on cerebral oxygen balance in neurosurgical patients

Objective: To assess the effects of various anesthetic techniques and PaCO2 levels on cerebral oxygen supply/consumption balance during craniotomy for removal of tumors, and to explore an anesthetic technique for neurosur-gery and an appropriate degree of PaCO2 during neuroanesthesia. Methods: One hundred and fourteen patients with supratentorial tumors for elective craniotomy, ASA grade I - II , were randomly allocated to six groups. Patients were anesthetized with continuous intravenous infusion of 2% procaine 1. 0 mg · kg-1 · min-1 in Group I , inhalation of 1. 0% - 1. 5% isoflurane in Group II , and infusion of 2% procaine 0. 5 mg·kg · min-1 combined with inhalation of 0.5% -0.7% isoflurane in Group III during the period of study. The end-tidal pressure of CO2(PET CO2 ) was maintained at 4.0 kPa in these 3 groups. In Group IV, V and VI, the anesthetic technique was the same as that in Group I but the PETCO2 was adjusted to 3. 5, 4. 0 and 4. 5 kPa respectively for 60 min during which the study was performed. The radial arterial and retrograde jugular venous blood samples were obtained at the onset and the end of this study for determining jugular venous bulb oxygen saturation ( SjvO2 ) , arteriovenous oxygen content difference (AVDO2) and cerebral extraction of oxygen (CEO2). Results: In Group I and I SjvO2, AVDO2 and CEO2 remained stable. Although SjvO2 kept constant, AVDO2 and CEO2 decreased significantly (P <0. 05) in Group II. Moreover, AVDO2 and CEO2 in Group II were significantly lower than those of Group III (P<0. 05). In Group IV, 60 min after hyperventilation, SjvO2 and jugular venous oxygen content ( CjvO2 ) decreased markedly (P < 0. 01 ) while CEO2 increased significantly ( P <0.01) . In addition, SjvO2, CjvO2 and CEO2 in Group IV were significantly different from the corresponding parameters in Group V and Group VI (P <0. 05) . In view of sustained excessive hyperventilation, SjvO2 was less than 50% in 37.5% patients of Group IV. Conclusion: Anesthesia with intravenous infusion of procaine combined with isoflurane inhalation proved to be more suitable for neurosurgery than procaine intravenous anesthesia or isoflurane inhalation anesthesia alone. PaCO2 at 4.0 -4. 5 kPa in patients undergoing craniocerebral surgery during neuroanesthesia would be beneficial in both decreasing ICP and maintaining cerebral oxygen supply/consumption balance.

Effects of DEX on sedation, neurological function and cerebral oxygen metabolism in elderly patients with prostate cancer undergoing LRP

Objective:To study the sedative effect of dexmedetomidine in elderly patients with prostate cancer undergoing three hole LRP,and its effect on nerve function and brain oxygen metabolism.Methods:From August 2016 to December 2019,78 patients with LRP under general anesthesia in our hospital were randomly selected and divided into control group and observation group according to the random number table method,39 cases in each group.During the operation,the observation group was given dextromethoridine,while the control group was given the same amount of normal saline.The changes of cognitive function index(MoCA score,POCD incidence rate),neurological function index(TGF-β1,NSE,IGF-1),brain oxygen metabolism index(PaO2,map,PaCO2,rSO2)before and after operation were compared between the two groups.The visual analogue score(VAS),the amount of analgesic drugs and the times of pressing the analgesic pump were compared between the two groups.The incidence of adverse reactions was compared between the two groups.Results:Before operation,there was no significant difference in cognitive function index,neurological function index and brain oxygen metabolism index between the two groups(P>0.05).On the first and third days after operation,MOCA score of the two groups was significantly lower,MOCA score of the observation group was significantly higher than that of the control group,POCD incidence of the observation group was significantly lower than that of the control group;on the third day after operation,TGF-β1 and IGF-1 of the two groups were significantly lower,TGF-β1 and IGF-1 of the observation group were significantly lower-The NSE in the observation group was significantly lower than that in the control group(P<0.05).In this study,1 hour after the establishment of pneumoperitoneum,PaCO2 and rSO2 in the two groups were significantly increased,6 hours and 12 hours after the operation,the VAS score of the observation group was lower than that of the control group,and the dosage of analgesic pump and the number of times of compression of the analgesic pump were significantly lower than that of the control group(P<0.05).There was no difference in the incidence of adverse reactions between the two groups(P>0.05).Conclusion:DEX has a good sedative effect on the elderly prostate cancer patients undergoing LRP with three hole method.It has little effect on nerve function and brain oxygen metabolism,and has a good safety.

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.

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.

USING FUNCTIONAL NEAR-INFRARED SPECTROSCOPY TO MEASURE COGNITIVE FUNCTION:WHEN WILL IT BECOME AN ACCEPTED CLINICAL TOOL FOR COGNITIVE AGING AND PRODROMAL DEMENTIA SCREENING?

This article presents a historical perspective of foundational studies utilizing near-infrared spectroscopy(NIRS)to measure the hemodynamics,oxygenation,and activation of the human brain cortex during cognitive tasks,called functional NIRS(fNIRS).It discusses studies representative of the diagnostic power and potential that fNIRS has shown for providing increased understanding of cognitive changes with aging and dementia.It concludes by discussing challenges that continue to confront the implementation of NIRS and fNIRS in clinical and translational research,in particular,the challenges to measure cognitive function and impairment in aged,chronically ill,and fragile subjects with or without dementia.It is written specifically in memoriam,honoring Britton Chance,therefore papers authored by him and his collaborative research family are weighted to illustrate the significant foundation and legacy he has left to this world.

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 fentanyl and sucrose on pain in retinopathy examinations with pain scale,near-infrared spectroscopy,and ultrasonography:a randomized trial

Background This study aimed to compare the efficacy of intravenous,intranasal fentanyl and oral sucrose in reducing the pain response during retinopathy of prematurity examinations using premature infant pain profile(PIPP)scores.Method The study included 42 infants who underwent retinopathy screening examinations.The infants were divided into three groups:oral sucrose,intranasal fentanyl,and intravenous fentanyl.Vital signs(heart rate,arterial oxygen saturation,and mean arterial pressure)were recorded.The PIPP was used to determine pain severity.Cerebral oxygenation and middle cerebral artery blood flow were evaluated using near-infrared spectroscopy and Doppler ultrasonography,respectively.The data obtained were compared between groups.Results There was no significant difference between the three groups regarding postconceptional and postnatal ages or birth weights and weight at the time of examination.All babies had moderate pain during the examination.No correlation was observed between analgesia method and pain scores(P=0.159).In all three groups,heart rate and mean arterial pressure increased,whereas oxygen saturation decreased during the exam compared with pre-examination values.However,heart rate(HR),mean arterial pressure(MAP)and arterial oxygen saturation(sPO2)values did not differ between groups(HR,P=0.150;MAP,P=0.245;sPO2,P=0.140).The cerebral oxygenation(rSO2)values between the three groups were found to be similar[rSO2:P=0.545,P=0.247,P=0.803;fractional tissue oxygen extraction(FTOE):P=0.553,P=0.278].Regarding cerebral blood flow values,we also did not find any difference between the three groups[mean blood flow velocity(Vmean):P=0.569,P=0.975;maximum flow velocity(Vmax):P=0.820,P=0.997].Conclusions Intravenous and intranasal fentanyl and oral sucrose were not superior to each other in preventing pain during the examination for retinopathy of prematurity(ROP).Sucrose may be a good alternative for pain control during ROP examination.Our findings suggest that ROP exam may not affect cerebral oxygenation or cerebral blood flow.Larger scale studies are needed to determine the best pharmacological option to reduce pain during ROP exams and evaluate the effects of this procedure on cerebral oxygenation and blood flow.