Association between peripheral perfusion index and postoperative acute kidney injury in major noncardiac surgery patients receiving continuous vasopressors: a post hoc exploratory analysis of the VEGA-1 trial.

BACKGROUND: The peripheral perfusion index is the ratio of pulsatile to nonpulsatile static blood flow obtained by photoplethysmography and reflects peripheral tissue perfusion. We investigated the association between intraoperative perfusion index and postoperative acute kidney injury in patients undergoing major noncardiac surgery and receiving continuous vasopressor infusions. METHODS: In this exploratory post hoc analysis of a pragmatic, cluster-randomised, multicentre trial, we obtained areas and cumulative times under various thresholds of perfusion index and investigated their association with acute kidney injury in multivariable logistic regression analyses. In secondary analyses, we investigated the association of time-weighted average perfusion index with acute kidney injury. The 30-day mortality was a secondary outcome. RESULTS: Of 2534 cases included, 8.9% developed postoperative acute kidney injury. Areas and cumulative times under a perfusion index of 3% and 2% were associated with an increased risk of acute kidney injury; the strongest association was observed for area under a perfusion index of 1% (adjusted odds ratio [aOR] 1.32, 95% confidence interval [CI] 1.00-1.74, P=0.050, per 100%∗min increase). Additionally, time-weighted average perfusion index was associated with acute kidney injury (aOR 0.82, 95% CI 0.74-0.91, P<0.001) and 30-day mortality (aOR 0.68, 95% CI 0.49-0.95, P=0.024). CONCLUSIONS: Larger areas and longer cumulative times under thresholds of perfusion index and lower time-weighted average perfusion index were associated with postoperative acute kidney injury in patients undergoing major noncardiac surgery and receiving continuous vasopressor infusions. CLINICAL TRIAL REGISTRATION: NCT04789330.

The Role of the Tissue Perfusion Index in Predicting Disease Severity and Prognosis in Patients with Severe and Critical COVID-19.

OBJECTIVES: The study investigated whether percutaneous partial pressure of oxygen (PtcO2), percutaneous partial pressure of carbon dioxide (PtcCO2), and the derived tissue perfusion index (TPI) can predict the severity and short-term outcomes of severe and critical COVID-19. DESIGN: Prospective observational study conducted from January 1, 2023 to February 10, 2023. SETTING: A teaching hospital specializing in tertiary care in Nanjing City, Jiangsu Province, China. PARTICIPANTS: Adults (≥18 years) with severe and critical COVID-19. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The general information and vital signs of the patients were collected. The PtcO2 and PtcCO2 were monitored in the left dorsal volar. The ratio of TPI was defined as the ratio of PtcO2/fraction of inspired oxygen (FiO2) to PtcCO2. Mortality at 28 was recorded. The ability of the TPI to assess disease severity and predict prognosis was determined. ENDPOINT: Severity of the disease on the enrollment and mortality at 28. RESULTS: A total of 71 patients with severe and critical COVID-19, including 40 severe and 31 critical cases, according to the COVID-19 treatment guidelines published by WHO, were recruited. Their median age was 70 years, with 56 (79%) males. The median SpO2/FiO2, PtcO2, PtcCO2, PtcO2/ FiO2, and TPI values were 237, 61, 42, 143, and 3.6 mm Hg, respectively. Compared with those for severe COVID-19, the TPI, PtcO2/ FiO2, SpO2/FiO2, and PtcO2 were significantly lower in critical COVID-19, while the PtcCO2 was significantly higher. After 28 days, 26 (37%) patients had died. TPI values < 3.5 were correlated with more severe disease status (AUC 0.914; 95% CI: 0.847-0.981, P < 0.001), and TPI < 3.3 was associated with poor outcomes (AUC 0.937; 95% CI 0.880-0.994, P < 0.001). CONCLUSIONS: The tissue perfusion index (TPI), PtcCO2, and PtcO2/ FiO2 can predict the severity and outcome of severe and critical COVID-19.

Prospective Evaluation of the Peripheral Perfusion Index in Assessing the Organ Dysfunction and Prognosis of Adult Patients With Sepsis in the ICU.

Background: The peripheral perfusion index (PI) reflects microcirculatory blood flow perfusion and indicates the severity and prognosis of sepsis. Method: The cohort comprised 208 patients admitted to the intensive care unit (ICU) with infection, among which 117 had sepsis. Demographics, medication history, ICU variables, and laboratory indexes were collected. Primary endpoints were in-hospital mortality and 28-day mortality. Secondary endpoints included organ function variables (coagulation function, liver function, renal function, and myocardial injury), lactate concentration, mechanical ventilation time, and length of ICU stay. Univariate and multivariate analyses were conducted to assess the associations between the PI and clinical outcomes. Sensitivity analyses were performed to explore the associations between the PI and organ functions in the sepsis and nonsepsis groups. Result: The PI was negatively associated with in-hospital mortality (odds ratio [OR] 0.29, 95% confidence interval [CI] 0.15 to 0.55), but was not associated with 28-day mortality. The PI was negatively associated with the coagulation markers prothrombin time (PT) (ß -0.36, 95% CI -0.59 to 0.13) and activated partial thromboplastin time (APTT) (ß -1.08, 95% CI -1.86 to 0.31), and the myocardial injury marker cardiac troponin I (cTnI) (ß -2085.48, 95% CI -3892.35 to 278.61) in univariate analysis, and with the PT (ß -0.36, 95% CI -0.60 to 0.13) in multivariate analysis. The PI was negatively associated with the lactate concentration (ß -0.57, 95% CI -0.95 to 0.19), mechanical ventilation time (ß -23.11, 95% CI -36.54 to 9.69), and length of ICU stay (ß -1.28, 95% CI -2.01 to 0.55). Sensitivity analyses showed that the PI was significantly associated with coagulation markers (PT and APTT) and a myocardial injury marker (cTnI) in patients with sepsis, suggesting that the associations between the PI and organ function were stronger in the sepsis group than the nonsepsis group. Conclusion: The PI provides new insights for assessing the disease severity, short-term prognosis, and organ function damage in ICU patients with sepsis, laying a theoretical foundation for future research.

Utility of non-invasive monitoring of exhaled carbon dioxide and perfusion index in adult patients in the emergency department.

BACKGROUND: Several noninvasive solutions are available for the assessment of patients at risk of deterioration. Capnography, in the form of end-tidal exhaled CO2 (ETCO2) and perfusion index (PI), could provide relevant information about patient prognosis. The aim of the present project was to determine the association of ETCO2 and PI with mortality of patients admitted to the emergency department (ED). METHODS: Multicenter, prospective, cohort study of adult patients with acute disease who needed continuous monitoring in the ED. The study included two tertiary hospitals in Spain between October 2022 and June 2023. The primary outcome of the study was in-hospital mortality (all-cause). Demographics, vital signs, ETCO2 and PI were collected. RESULTS: A total of 687 patients were included in the study. The in-hospital mortality rate was 6.8%. The median age was 79 years (IQR: 69-86), and 63.3% were males. The median ETCO2 value was 30 mmHg (26-35) in survivors and 23 mmHg (16-30) in nonsurvivors (p = 0.001). For the PI, the medians were 4.7% (2.8-8.1) for survivors and 2.5% (0.98-4-4) for nonsurvivors (p < 0.001). The model that presented the best AUC was age (odds ratio (OR): 1.02 (1.00-1.05)), the respiratory rate (OR: 1.06 (1.02-1.11)), and the PI (OR: 0.83 (0.75-0.91)), with a result of 0.840 (95% CI: 0.795-0.886); the model with the respiratory rate (OR: 1.05 (1.01-1.10)), the PI (OR: 0.84 (0.76-0.93)), and the ETCO2 (no statistically significant OR), with an AUC of 0.838 (95% CI: 0.787-0.889). CONCLUSIONS: The present study showed that the PI and respiratory rate are independently associated with in-hospital mortality. Both the PI and ETCO2 are predictive parameters with improved prognostic performance compared with that of standard vital signs.

Prediction of preload dependency using phenylephrine-induced peripheral perfusion index during general anaesthesia: a prospective observational study.

BACKGROUND: Tracking preload dependency non-invasively to maintain adequate tissue perfusion in the perioperative period can be challenging.The effect of phenylephrine on stroke volume is dependent upon preload. Changes in stroke volume induced by phenylephrine administration can be used to predict preload dependency. The change in the peripheral perfusion index derived from photoplethysmography signals reportedly corresponds with changes in stroke volume in situations such as body position changes in the operating room. Thus, the peripheral perfusion index can be used as a non-invasive potential alternative to stroke volume to predict preload dependency. Herein, we aimed to determine whether changes in perfusion index induced by the administration of phenylephrine could be used to predict preload dependency. METHODS: We conducted a prospective single-centre observational study. The haemodynamic parameters and perfusion index were recorded before and 1 and 2 min after administering 0.1 mg of phenylephrine during post-induction hypotension in patients scheduled to undergo surgery. Preload dependency was defined as a stroke volume variation of ≥ 12% before phenylephrine administration at a mean arterial pressure of < 65 mmHg. Patients were divided into four groups according to total peripheral resistance and preload dependency. RESULTS: Forty-two patients were included in this study. The stroke volume in patients with preload dependency (n = 23) increased after phenylephrine administration. However, phenylephrine administration did not impact the stroke volume in patients without preload dependency (n = 19). The perfusion index decreased regardless of preload dependency. The changes in the perfusion index after phenylephrine administration exhibited low accuracy for predicting preload dependency. Based on subgroup analysis, patients with high total peripheral resistance tended to exhibit increased stroke volume following phenylephrine administration, which was particularly prominent in patients with high total peripheral resistance and preload dependency. CONCLUSION: The findings of the current study revealed that changes in the perfusion index induced by administering 0.1 mg of phenylephrine could not predict preload dependency. This may be attributed to the different phenylephrine-induced stroke volume patterns observed in patients according to the degree of total peripheral resistance and preload dependency. TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN000049994 on 9/01/2023).

Peripheral perfusion index as a predictor of reintubation in critically ill surgical patients.

PURPOSE: We aimed to evaluate the ability of the peripheral perfusion index (PPI) to predict reintubation of critically ill surgical patients. METHODS: This prospective observational study included mechanically ventilated adults who were extubated after a successful spontaneous breathing trial (SBT). The patients were followed up for the next 48 h for the need for reintubation. The heart rate, systolic blood pressure, respiratory rate, peripheral arterial oxygen saturation (SpO2), and PPI were measured before-, at the end of SBT, 1 and 2 h postextubation. The primary outcome was the ability of PPI 1 h postextubation to predict reintubation using area under the receiver operating characteristic curve (AUC) analysis. Univariate and multivariate analyses were performed to identify predictors for reintubation. RESULTS: Data from 62 patients were analysed. Reintubation occurred in 12/62 (19%) of the patients. Reintubated patients had higher heart rate and respiratory rate; and lower SpO2 and PPI than successfully weaned patients. The AUC (95%confidence interval) for the ability of PPI at 1 h postextubation to predict reintubation was 0.82 (0.71-0.91) with a negative predictive value of 97%, at a cutoff value of ≤ 2.5. Low PPI and high respiratory rate were the independent predictors for reintubation. CONCLUSION: PPI early after extubation is a useful tool for prediction of reintubation. Low PPI is an independent risk factor for reintubation. A PPI > 2.5, one hour after extubation can confirm successful extubation.

The Urethral Perfusion Index During Off-Pump Coronary Artery Bypass Surgery: An Observational Study.

OBJECTIVES: The IKORUS system (Vygon, Écouen, France) allows continuous monitoring of the urethral perfusion index (uPI) using a photoplethysmographic sensor mounted near the base of the balloon of a dedicated urinary catheter. We aimed to test the hypothesis that the uPI decreases during off-pump coronary artery bypass (OPCAB) surgery and to investigate the relationship between the uPI and macrocirculatory variables. DESIGN: Prospective observational study. SETTING: University Medical Center Hamburg-Eppendorf, Hamburg, Germany. PARTICIPANTS: Twenty patients having OPCAB surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary endpoint was changes in the uPI during OPCAB surgery. We additionally investigated associations between the uPI and cardiac output, mean arterial pressure, heart rate, and point-of-care variables. Twenty patients with 24,137 uPI measurements were included. Overall, there was a high interindividual variability in the uPI. Compared with the preparation phase (during which the median [interquartile range] uPI was 7.7 [5.6-12.0]), the uPI decreased by 14% (95% CI 13%-15%) during the bypass grafting phase, by 35% (95% CI 34%-36%) during the cardiac positioning phase, and by 7% (95% CI 6%-9%) during hemostasis. There was no clinically important association between uPI and either cardiac output, mean arterial pressure, or heart rate. CONCLUSIONS: The uPI decreases during OPCAB surgery, specifically during the cardiac positioning phase. There was no clinically important association between uPI and either cardiac output, mean arterial pressure, or heart rate. It, therefore, remains to be determined whether intraoperative uPI decreases are clinically important, reflect alterations in intra-abdominal tissue perfusion that are not reflected by systemic macrohemodynamics, and can help clinicians guide therapeutic interventions.

Goal-directed fluid therapy guided by plethysmographic variability index versus conventional liberal fluid therapy in neonates undergoing abdominal surgery: A prospective randomized controlled trial.

BACKGROUND: Intraoperative fluid therapy maintains normovolemia, normal tissue perfusion, normal metabolic function, normal electrolytes, and acid-base status. Plethysmographic variability index has been shown to predict fluid responsiveness but its role in guiding intraoperative fluid therapy is still elusive. AIMS: The aim of the present study was to compare intraoperative goal-directed fluid therapy based on plethysmographic variability index with liberal fluid therapy in term neonates undergoing abdominal surgeries. METHODS: A prospective randomized controlled study was conducted in a tertiary care centre, over a period of 18 months. A total of 30 neonates completed the study out of 132 neonates screened. Neonates with tracheoesophageal fistula, congenital diaphragmatic hernia, congenital heart disease, respiratory disorders, creatinine clearance <90 mL/min and who were hemodynamically unstable were excluded. Neonates were randomized to goal-directed fluid therapy group where the plethysmographic variability index was targeted at <18 or liberal fluid therapy group. Primary outcome was comparison of total amount of fluid infused intraoperatively in both the groups. Secondary outcomes included intraoperative and postoperative arterial blood gas parameters, biochemical parameters, use of vasopressors, number of fluid boluses, complications and duration of hospital stay. RESULTS: There was no significant difference in total intraoperative fluid infused [90 (84-117.5 mL) in goal-directed fluid therapy and 105 (85.5-144.5 mL) in liberal fluid therapy group (p = .406)], median difference (95% CI) -15 (-49.1 to 19.1). There was a decrease in serum lactate levels in both groups from preoperative to postoperative 24 h. The amount of fluid infused before dopamine administration was significantly higher in liberal fluid therapy group (58 [50.25-65 mL]) compared to goal-directed fluid therapy group (36 [22-44 mL], p = .008), median difference (95% CI) -22 (-46 to 2). In postoperative period, the total amount of fluid intake over 24 h was comparable in two groups (222 [204-253 mL] in goal-directed fluid therapy group and 224 [179.5-289.5 mL] in liberal fluid therapy group, p = .917) median difference (95% CI) cutoff -2 (-65.3 to 61.2). CONCLUSION: Intraoperative plethysmographic variability index-guided goal-directed fluid therapy was comparable to liberal fluid therapy in terms of total volume of fluid infused in neonates during perioperative period. More randomized controlled trials with higher sample size are required. TRIAL REGISTRATION: Central Trial Registry of India (CTRI/2020/02/023561).

Diagnostic utility of perfusion index in identifying radial artery embolism during hyperthermic intraperitoneal chemotherapy procedure: a case report.

Invasive arterial cannulation is a widely used method in intensive care units and operating rooms. However it has potential complications such as thrombosis, peripheral embolism, hematoma formation, and infection. The Masimo Root Radical-7 Pulse CO-Oximeter® (Masimo Corporation, Irvine, CA, USA) is a non-invasive hemodynamic monitoring device that measures perfusion index and pleth variability index, provides guidance to anaesthesiologists in the cases where hemodynamic fluctuations are expected. In this particular case, the perfusion index played a crucial role in the immediate diagnosis of radial artery embolism in a patient undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy procedure.

Correlation of Block Success with Perfusion Index Measurement in Cases of Pediatric Surgery Under Caudal Epidural Block Anesthesia.

PURPOSE: One of the regional anesthetic procedures, caudal epidural block, is important for lower extremities surgeries in the pediatric patient population. The perfusion index (PI) value, which reflects vasomotor tone, can be used to indicate block success. The aim was to compare the role of perfusion index, heart rate, and mean arterial pressure in detecting the success of caudal epidural block and to investigate whether perfusion index was an earlier indicator in determining the success of the block in pediatric surgery cases. DESIGN: A randomized controlled trial. METHODS: The study included 58 patients, American Society of Anesthesiologists'classification 1, between the ages 1 and 6 years. In the left lateral decubitus posture, caudal epidural block was performed using a 23 or 25-gauge caudal needle and a dosage of 0.25% bupivacaine (1 mL/kg). At the 0, 1, 5, 7, 10, 15, and 20th minutes, peripheral oxygen saturation, heart rate, mean arterial pressure, and PI values were obtained using a probe attached to the first toe of the left foot. A successful caudal epidural block indication was defined as an increase of at least 100% in the PI value over the baseline value and a 15% decrease in mean arterial pressure and heart rate FINDINGS: PI represents the ratio of the photoplethysmography signal to pulsatile over nonpulsatile light absorbance. An increase in the PI value indicates that the block is effective. In the 20-minute follow-up period after caudal epidural block, there was at least a 100% increase in PI value in all of the patients at the seventh minute. An expected 15% reduction in mean arterial pressure was observed in 14.5% of the patients and an expected 15% reduction in heart rate was observed in 45.6% of the patients. CONCLUSIONS: The results obtained from our study show that the increase in PI values is associated with caudal epidural block success. The PI value is more rapid, sensitive and objective than those produced by other parameters. Benefits include an earlier change in anesthesia management due to block failure and faster initiation to surgery, which reduces exposure to anesthetic chemicals.

Correlation coefficient between plethysmographic variability index and Systolic Pressure Variation as an indicator for fluid responsiveness in hypotensive patients in the ICU/OT.

Background: Prediction of fluid responsiveness in hypotensive patients is a challenge. The correlation between a novel noninvasive dynamic indicator, Pleth Variability Index (PVI ®), and a gold-standard Systolic Pressure Variation (SPV) as a measure of fluid responsiveness was assessed in the Intensive Care Unit (ICU) or Operation Theatre (OT) in a tertiary care hospital. Methods: A prospective experimental study was conducted over a span of one year on 100 mechanically ventilated patients with hypotension. Vital parameters along with SPV and PVI ® were recorded before and after a standard volume expansion protocol. A 10% SPV threshold was used to define fluid responders and nonresponders. Results: Pearson's correlation graph at baseline showed positive correlation between PVI ® and SPV (r = 0.59, p-value = 0.001). Strength of correlation was comparatively less but still showed positive correlation at 15 (r = 0.39, p-value = 0.009) and 30 (r = 0.404, p-value = 0.004) minutes of fluid bolus. The Bland Altman analysis of baseline values of PVI ® and SPV showed good agreement with a mean bias of 9.05. Percentage change of PVI ® and SPV over 30 min showed a statistically significant positive correlation in the responder group (r = 0.53, p < 0.05). A threshold value of PVI ® more than 18% before volume expansion differentiated fluid responders and nonresponders with a sensitivity of 75% and specificity of 67%, with an area under Receiver Operating Characteristic (ROC) of 0.78. Conclusion: A positive correlation exists between SPV and PVI ®, justifying the use of noninvasive PVI ® in a clinical setting of hypotension.

Evaluation of perfusion index as a predictor of successful caudal block in pediatric patients: A prospective randomized study.

Background and Aims: Caudal block is among the most widely administered regional anesthesia in pediatric patients. The clinical signs and objective assessments are not fast and reliable enough to provide a good feedback. Perfusion index (PI) is considered as a sensitive marker to assess the efficacy of caudal block. We aim to assess PI as an indicator for success of caudal block in pediatric patients. Material and Methods: Sixty pediatric patients scheduled for elective surgery of lower abdomen and below were included. Patients were randomly allocated into two groups (n = 30): Group 1 received caudal block after general anesthesia and Group 2 only received general anesthesia. PI, heart rate, mean arterial pressure, and anal sphincter tone (AST) were recorded at 5, 10, 15, and 20 min following induction of anesthesia. Results: A persistent increase in the PI value was observed in Group 1 starting from 5 min till 20 min, as compared to Group 2, at all the time intervals. When mean PI was statistically compared between both the groups, it was found to be highly significant (P = 0.001). Group 1 patients have progressive laxity of AST which was found to be significantly different from Group 2 (P < 0.001). Conclusion: We have found that both PI and AST are good indicators for assessing success of caudal block onset in pediatric patients but AST took slightly longer time (~20 mins). Therefore, we conclude that PI is simple, economical, and noninvasive monitor that predicts the caudal onset much earlier than AST.

Perfusion index to predict post spinal hypotension in lower segment caesarean section.

Background and Aims: It is important to predict and prevent post-spinal hypotension in lower segment cesarean section (LSCS). Peripheral vascular tone can be monitored as a perfusion index (PI) from a pulse oximeter. We aimed to study baseline PI as a predictor of post-spinal hypotension in LSCS. Material and Methods: Prospective observational study conducted in a tertiary care teaching public hospital on patients posted for elective LSCS under spinal anesthesia. Baseline PI and hypotension were compared. A receiver operating characteristic (ROC) curve was plotted and data were analyzed using SPSS version 20. Results: Among 90 females, 43 (47.8%) had a PI ≤3.5 and 47 (52.2%) had a PI >3.5. In the PI >3.5 group, 46 (97.9%) females had hypotension and required a high volume of IV fluids, and 29 (61.7%) required vasopressors, and the association with PI was statistically significant with Pearson's Chi-square values of 32.26 and 32.36, respectively (P = 0.001). In the ROC, the area under the curve (AUC) was 0.917, proving baseline PI >2.9 as an excellent classifier (P < 0.0001,95% confidence interval [CI] 0.840-0.965) and can predict hypotension with a sensitivity of 83.08% and specificity of 96.00%. Conclusion: Baseline PI >3.5 was associated with significant post-spinal hypotension and vasopressor administration in LSCS. We established baseline PI >2.9 can predict post-spinal hypotension with high sensitivity and specificity. PI is simple, quick, and non-invasive and can be used as a predictor for post-spinal hypotension in parturients undergoing LSCS so that prophylactic measures can be considered in at-risk patients for better maternal and fetal outcomes.

Peripheral perfusion index in well newborns at 6 to 72 h of life at different altitudes: a multi-center study in China.

The purpose of this study is to obtain the reference range of peripheral perfusion index (PPI) of asymptomatic well newborns at 6 to 72 h of life at different altitudes. A population-based prospective cohort study was conducted in cities at different altitudes in China. Asymptomatic well newborns were enrolled consecutively from six hospitals with an altitude of 4 to 4200 m between February 1, 2020, and April 15, 2021. PPI was measured at 6, 12, 24, 48, and 72 h after birth on the right hand (pre-ductal) and either foot (post-ductal) using a Masimo SET Radical-7 oximeter. Fiftieth percentile reference curves of the pre- and post-ductal PPI values at 6-72 h after birth were generated using the Lambda Mu Sigma method. Linear mixed-effects regression was performed to determine the influence of different altitude levels on PPI values over different measurement time points. A total of 4257 asymptomatic well newborns were recruited for analysis. The median and quartile pre- and post-ductal PPI values at 6-72 h of life at different altitudes were 1.70 (1.20, 2.60) and 1.70 (1.10, 2.70) for all infants, 1.30 (1.10, 1.90) and 1.10 (0.88, 1.80) for infants at low altitude, 1.40 (1.00, 2.00) and 1.30 (0.99, 2.00) at mild altitudes, 1.90 (1.30, 2.50) and 1.80 (1.20, 2.70) at moderate altitudes, 1.80 (1.40, 3.50) and 2.20 (1.60, 4.30) for high altitudes, 3.20 (2.70, 3.70), and 3.10 (2.10, 3.30) for higher altitudes, respectively. Overall, both pre- and post-ductal PPI increased with altitude. The 50th percentile curves of pre- and post-ductal PPI values in well newborns at mild, low, moderate, and high altitudes were relatively similar, while the difference between the PPI curves of infants at higher altitudes and other altitudes was significantly different.  Conclusions: With the increase of altitude, pre- and post-ductal PPI of newborns increases. Our study obtained the PPI reference values of asymptomatic well newborns at 6 to 72 h after birth at different altitudes from 4 to ≥ 4000 m. What is Known: • Monitoring hemodynamics is very important to neonates. As an accurate and reliable hemodynamic monitoring index, PPI can detect irreversible damage caused by insufficient tissue perfusion and oxygenation early, directly, noninvasively, and continuously. What is New: • Our study obtained the PPI reference values of asymptomatic well newborns at 6 to 72 h after birth at different altitudes from 4 to ≥ 4000 m. With the increase of altitude, pre- and post-ductal PPI of newborns increase with statistical significance. Therefore, the values and disease thresholds of PPI for asymptomatic neonates should be modified according to altitudes.

Comparison of the perfusion index as an index of noxious stimulation in monitored anesthesia care of propofol/remifentanil and propofol/dexmedetomidine: a prospective, randomized, case-control, observational study.

BACKGROUND: Dexmedetomidine, one of the sedatives, has an analgesic effect. We aimed to investigate postoperative analgesia with dexmedetomidine as adjuvants for procedural sedation using perfusion index (PI). METHODS: In this prospective, randomized, case-control, observational study, 72 adult patients, 19-70 years, who were scheduled for chemoport insertion under monitored anesthesia care were performed. According to the group assignment, remifentanil or dexmedetomidine was simultaneously infused with propofol. The primary outcome was PI 30 min after admission to the post anesthesia care unit (PACU). And, pain severity using numerical rating scale (NRS) score and the relationship between NRS score and PI were investigated. RESULTS: During PACU staying, PI values were significantly different between the two groups PI values at 30 min after admission to the PACU were 1.3 (0.9-2.0) in the remifentanil group and 4.5 (2.9-6.8) in the dexmedetomidine group (median difference, 3; 95% CI, 2.1 to 4.2; P < 0.001). The NRS scores at 30 min after admission to the PACU were significantly lower in the dexmedetomidine group (P = 0.002). However, there was a weak positive correlation between NRS score and PI in the PACU (correlation coefficient, 0.188; P = 0.01). CONCLUSION: We could not find a significant correlation between PI and NRS score for postoperative pain control. Using PI as a single indicator of pain is insufficient. TRIAL REGISTRATION: Clinical Trial Registry of Korea, https://cris.nih.go.kr : KCT0003501, the date of registration: 13/02/2019.

The utility of the perfusion index as an indicator of anesthetic depth for repeated propofol sedation in children: An observational study.

BACKGROUND: Children receiving proton therapy require repeated sedation. In this study, we aimed to investigate the utility of the perfusion index (PI) for evaluating consciousness level during repeated propofol sedation. METHODS: In this prospective observational study, children aged from birth to 19 years old scheduled for proton therapy under repeated propofol sedation were enrolled. The primary outcome was the equivalence of PI values 5 min after anesthesia induction on consecutive sedation. Total consumption of propofol during sedation, time to reach the University of Michigan sedation scale (UMSS) score 1 after end of proton therapy, and duration of post-anesthesia care unit (PACU) stay were recorded. RESULTS: The PI values measured 5 min after induction of anesthesia were not equivalent to each other in consecutive sedation except for the second versus third (1st vs. 2nd: 97.5% CI: -1.34, 0.91; p = 0.206, 0.034; 2nd vs. 3rd: 97.5% CI: -0.87, 0.94; p = 0.023, 0.036 3rd vs. 4th: 97.5% CI: -2.08, -0.26; p < 0.99, <0.001; 4th vs. 5th: 97.5% CI: 0.21, 2.28; p < 0.001, >0.99; respectively). In consecutive sedation, there was not a significantly different difference in the time to reach UMSS score 1 (p > 0.99, all) for total consumption of propofol, time to reach UMSS score 1 after the end of proton therapy, and duration of PACU stay. CONCLUSIONS: During repeated propofol sedation in children, PI was insufficient to be used as an indicator of consciousness level assessment. However, we suggest that the information related to repeated sedation provided by this study may be helpful in clinical practice.

Perfusion index in newborns with CHD without clinical signs of hypoperfusion and heart failure: comparison with healthy newborns.

INTRODUCTION: Peripheral perfusion index has been proposed as a possible method for detecting circulatory impairment. We aimed to determine the normal range of peripheral perfusion index in healthy newborns and compare it with that of newborns with CHD. METHODS: Right-hand saturation and right-hand peripheral perfusion index levels were recorded, and physical examination and echocardiography were performed in newborns who were 0-28 days old and whom were evaluated in our paediatric cardiology outpatient clinic. The saturation and peripheral perfusion index levels of newborns with normal heart anatomy and function were compared with those of newborns with CHD. RESULTS: Out of 358 newborns (238 mature and 75 premature) enrolled in the study, 39 had CHD (20 mild CHD, 13 moderate CHD, and 6 severe CHD), of which 29 had CHD with left-to-right shunting, 5 had obstructive CHD, and 5 had cyanotic CHD. No newborn had clinical signs of hypoperfusion or heart failure, such as prolonged capillary refill, weakened pulses, or coldness of extremities. Peripheral perfusion index level was median (interquartile range) 1.7 (0.6) in healthy newborns, 1.8 (0.7) in newborns with mild CHD, and 1.8 (0.4) in newborns with moderate and severe CHD, and there was no significant difference between the groups regarding peripheral perfusion index level. CONCLUSION: Peripheral perfusion index remains unchanged in newborns with CHD without the clinical signs of hypoperfusion or heart failure. Larger studies with repeated peripheral perfusion index measurements can determine how valuable this method will be in the follow-up of newborns with CHD.

Evaluation of perfusion index and left ventricular output changes in low cardiac output syndrome after arterial switch operation.

INTRODUCTION: Transposition of great arteries is one of newborns' most common cyanotic CHDs, and its treatment is arterial switch operation in the first days of life. Low cardiac output syndrome may develop in the early postoperative period. In this study, we evaluated perfusion index and left ventricular output blood flow changes in patients who underwent arterial switch operation and developed low cardiac output syndrome. METHODS: This study was conducted prospectively in newborns with transposition of great arteries who underwent arterial switch operation between 1st August 2020 and 1st August 2022. Low cardiac output syndrome score and left ventricular output were investigated. Initially, 6th, 12th, 18th, and 24th hour perfusion index and left ventricular output values of patients with and without low cardiac output syndrome were recorded. The results were evaluated statistically. RESULTS: A total of 60 patients were included in the study. Sex distribution was equal. The median age at the time of surgery was 5 days (interquartile range 3-7 days), and the median weight was 3.1 kg (interquartile range 2.9-3. 4). Low cardiac output syndrome was detected in 30% (n = 18) of cases. The median perfusion index of patients who developed low cardiac output syndrome was significantly lower at the 12th, 18th, and 24th hours (p < 0.05) (0.99 versus 1.25, 0.86 versus 1.21, and 0.96 versus 1.33, respectively). Similarly, the median left ventricular output of patients who developed low cardiac output syndrome was significantly lower at 12th, 18th, and 24th hours (p < 0.05) (95 versus 110 ml/kg/min, 89 versus 109 ml/kg/min, and 92 versus 112 ml/kg/min, respectively). There was a significant correlation between perfusion index values and left ventricular output at all measurements (r > 0.500, p < 0.05). CONCLUSION: Perfusion index and left ventricular output measurements decreased in newborns who developed low cardiac output syndrome after arterial switch operation, especially at 12th and 18th hours. Serial perfusion index and left ventricular output measurements can be instructive in predicting low cardiac output syndrome development.

Comparison of two techniques of goal directed fluid therapy in elective neurosurgical patients - a randomized controlled study.

BACKGROUND: Goal directed fluid therapy (GDFT) may be a rational approach to adopt in neurosurgical patients, in whom intravascular volume optimization is of utmost importance. Most of the parameters used to guide GDFT are derived invasively. We postulated that the total volume of intraoperative intravenous fluid administered during elective craniotomy for supratentorial brain tumours would be comparable between two groups receiving GDFT guided either by the non-invasively derived plethysmography variability index (PVI) or by stroke volume variation (SVV). METHODS: 60 ASA category 1, 2 and 3 patients between 18 and 70 years of age were randomized to receive intraoperative fluid guided either by SVV (SVV group; n = 31) or PVI (PVI group; n = 29). The total volume of fluid administered intraoperatively was recorded. Serum creatinine was measured before the surgery, at the end of the surgery, 24 h after surgery and on the fifth post-operative day. Arterial cannulation was performed before induction in all patients. Serum lactate was measured before induction, once in 2 h intraoperatively, at the end of the surgery and 24 h after the surgery. Brain relaxation score was assessed by the surgeon during dural opening and dural closure. Patients were followed up till discharge or death. The duration of mechanical ventilation and the duration of hospital stay was noted for all patients. RESULTS: The volume of fluid given intraoperatively was significantly higher in the SVV group (p = 0.005). The two groups were comparable with respect to serum lactate and serum creatinine measured at pre-determined time intervals. Brain relaxation score was also comparable between the groups. SVV and PVI displayed moderate to strong correlation intraoperatively. The duration of mechanical ventilation and the length of the hospital stay were comparable between the two groups. CONCLUSIONS: PVI and SVV are equally effective in guiding GDFT in adults undergoing elective craniotomy for supratentorial brain tumours.

Dyspnea: perfusion index and triage status.

PURPOSE: To determine the relationship between perfusion index and the emergency triage classification in patients admitted to the emergency department with dyspnea. METHODS: Adult patients who presented with dyspnea and whose perfusion index values ​​were measured with Masimo Radical-7 device at the time of admission, at the first hour and the second hour of admission were included in the study. The PI and oxygen saturation measured by finger probes were compared and the superiority of their effects on the emergency triage classification was compared. RESULTS: For the 0.9 cut- off value of the arrival PI level according to the triage status; sensitivity 79.25%; specificity 78.12%; positive predictive value is 66.7 and negative predictive value is 87.2. A statistically significant correlation was found between the triage status and the 0.9 cut- off value of the admission PI level. We can say that the ODDS rate of red triage is 13.63 times (95% CI: 5.99-31.01) times higher in cases with a PI level of 0.9 and below. In the ROC analysis, the cut-off value of 1.1 and above the admission PI level was determined as the most appropriate point for discharge. CONCLUSION: The perfusion index can help to determine the triage classification in emergency departments for dyspnea.