A systematic review and meta-analysis on the use of preemptive hemodynamic intervention to improve postoperative outcomes in moderate and high-risk surgical patients

Fluid balance dynamics and early postoperative outcomes in orthotopic liver transplantation: a prospective cohort study

INTRODUCTION

This study evaluates the impact of Fluid Balance (FB) patterns on outcomes after Orthotopic Liver Transplantation (OLT). It hypothesizes that deviations from optimal FB increase morbidity.

METHODS

In a single-center cohort post hoc analysis of 73 post-OLT patients, FB was categorized into three groups based on cumulative FB at 72 hours: Lowest (negative FB), Intermediate (0-2000 mL), and Highest (> 2000 mL). We analyzed Sequential Organ Failure Assessment (SOFA) scores, mortality rates, and causes of death. Logistic regression identified mortality predictors.

RESULTS

The Highest FB group had the highest SOFA scores and mortality (Group "Lo": 18.2%, Group "In": 8.6%, Group "Hi": 40.5%, p = 0.009). A U-shaped relationship between FB and hospital mortality was observed, with extremes of FB associated with higher mortality. Cumulative FB independently predicted all-cause mortality with a 29.5% increase in the risk of death. FB on day 3 also predicted all-cause mortality, increasing the risk by 83.9%. Furthermore, FB on day 1 was linked to a 134.5% increase in the risk of death due to primary non-function of the liver. SOFALIVER score strongly predicted all-cause mortality, with a one-point increase associated with a 98.8% to 114.7% increase in mortality risk.

DISCUSSION

These findings suggest that both negative and positive extremes of FB are associated with worse outcomes after OLT, reinforcing the U-shaped relationship between FB and mortality. Our results underscore the importance of balanced fluid management, particularly in the early postoperative period. The study highlights the need for individualized FB strategies to optimize organ function and reduce mortality. The use of SOFALIVER scores as a predictor of mortality further emphasizes the importance of liver function monitoring in post-OLT patients. However, the single-centre design and convenience sample limit the generalizability of our findings, necessitating validation through multicenter studies.

CONCLUSION

Our study provides valuable insights into the relationship between FB patterns and mortality in OLT patients. Both negative and positive extremes of FB are associated with higher mortality, suggesting the need for a balanced and individualized fluid management approach. The strong predictive value of SOFALIVER scores for all-cause mortality highlights the importance of early and continuous monitoring of liver function. Future multicenter randomized controlled trials are needed to validate these findings and develop optimized fluid management protocols for OLT patients.

Simplified Enhanced Recovery After Surgery Intraoperative Fluid Management

INTRODUCTION

This study evaluates the efficacy of a simplified intraoperative fluid administration metric within enhanced recovery after surgery (ERAS) pathways. The objective is to optimize fluid management to improve postoperative outcomes, specifically kidney function.

METHODS

A retrospective evaluation was conducted at Massachusetts General Hospital on adult patients who underwent open hysterectomy, colectomy, and gastrectomy as part of ERAS pathways. The proposed fluid metric, set at 500 mL/h, was assessed against traditional methods of fluid administration. Data on serum creatinine (Cr) changes as defined as the difference between the baseline value and the maximum value within 1 week of surgery were collected, and compliance with the metric was monitored. Analysis involved Wilcoxon rank-sum test, Kruskal-Wallis test, and quantile regression.

RESULTS

The study included 1028 patients. Regression analysis indicated that compared to patients who received the optimal fluid quantity, those receiving below the optimal range showed an absolute increase in median Cr levels of 0.03 mg/dl (95% confidence interval = -0.005, 0.05) while those who received above the optimal range demonstrated an absolute increase in median Cr level of 0.01 (95% confidence interval = -0.03, 0.05).

CONCLUSIONS

The new fluid metric demonstrated a balanced approach to fluid administration, reducing the risk of overhydration while maintaining sufficient hydration. Additionally, implementing a simplified fluid metric of 500 mL/h in ERAS pathways is effective in improving postoperative kidney function. This approach facilitates adherence to fluid guidelines and can be applied across various healthcare settings. This metric serves as a practical, evidence-based pathway for fluid administration for most patients undergoing most ERAS procedures.

How low can we go: Achieving postoperative day 1 discharge after deep inferior epigastric perforator, a safe and feasible goal

BACKGROUND

Although rare reports describe discharge to be possible within 48 hours for patients undergoing autologous breast reconstruction, average length of stay remains around 3 days. This study aimed to demonstrate that patients can be safely discharged within 1 day after deep inferior epigastric perforator (DIEP) flap breast reconstruction.

METHODS

A retrospective review was performed of patients who underwent free flap breast reconstruction by a single surgeon from November 2021 to May 2024. Demographics, operative details, opioid ingestion, length of stay, and postoperative complications were reviewed to assess safety of discharge in 24 hours.

RESULTS

One hundred sixty-four DIEP flaps were performed on 119 patients. Average length of stay was 1.5 days (SD 0.7 days), with 67 (56.3%) patients discharged on postoperative day 1 (POD1) and 52 (43.7%) discharged after POD1. Of those discharged on POD1, 13 (19.4%) went home in <24 hours. Comparing patients discharged on POD1 to those discharged after POD1, there were statistically significant differences in reconstruction laterality (76.1% vs 44.2% unilateral, p<0.001), operative time (341.0 vs 439.1 minutes, p<0.001), and opioid ingestion on POD1 (4.2 IV morphine milligram equivalents [MME] vs 11.3 MME, p<0.001). Common complications included abdominal wound dehiscence (10.1%), abdominal seroma (5.0%), breast wound dehiscence (4.9%), and breast mastectomy flap necrosis (3.0%). Seventy-six (63.9%) patients had no complications. Overall success rate of flap reconstruction was 100%.

CONCLUSION

Collaboration among surgery, anesthesia, and dedicated nursing teams allow 23-hour observation or outpatient DIEP reconstruction to be safe and feasible. By attaining equivalency with implant-based reconstruction, access to flap reconstruction can be extended to more patients.

Current Practices of Haemodynamic Monitoring in High-Risk Surgical Patients: A Nationwide Survey Among Malaysian Anaesthesiologists

BACKGROUND

Advanced haemodynamic monitoring has been recommended for use in high-risk surgeries and high-risk patients undergoing surgery. This study aims to assess the current practices of haemodynamic monitoring in high-risk surgical patients among Malaysian anaesthesiologists.

METHODOLOGY

This is a cross-sectional survey among Malaysian anaesthesiologists, following approval from the institution's Medical Research Ethics Committee and the National Medical Research Register. The survey utilised a questionnaire developed by Cannesson et al. to gather demographic data, practice information, and haemodynamic monitoring practices. Statistical analysis was performed using SPSS, and results were presented as the mean, median, or frequency as appropriate.

RESULTS

A total of 366 participants responded to the questionnaire, and 2 dropped out due to an incomplete form. This study found differences in the frequency of haemodynamic optimisation and monitoring techniques used in different healthcare settings. Written protocols or statements concerning haemodynamic management in high-risk surgical cases were only available to 15.7% of participants in the institution. The overall utilisation rate of cardiac output monitoring was found to be 31.1%, with a significant majority of the usage observed in university hospitals (p < 0.001). Central venous pressure was more commonly used in university hospitals and private hospitals compared to public hospitals (p < 0.001). The usage of advanced parameters such as stroke volume variation, cardiac index, and systemic vascular resistance was significantly higher in university hospitals, with a p value < 0.001. Transthoracic echocardiography was the most common tool used for high-risk surgical patients. The primary reasons for participants not utilising cardiac output monitoring include the lack of availability of such monitoring in their respective settings, which constitutes 66.9% of the respondents. The overwhelming majority of participants, namely 98%, expressed the belief that there is room for improvement in their present haemodynamic care.

CONCLUSIONS

This study offers significant insights into the prevailing haemodynamic monitoring practices employed by Malaysian anaesthesiologists in the context of high-risk surgical patients. The findings have the potential to contribute to future educational initiatives and establish practice standards for haemodynamic monitoring in high-risk surgical procedures.

Perioperative Fluid Management

The medical complexity of the geriatric patients has been steadily rising. Still, as outcomes of surgical procedures in the older adults are improving, centers are pushing boundaries. There is also a growing appreciation of the importance of perioperative fluid management on postoperative outcomes, especially in the older adults. Optimal fluid management in this cohort is challenging due to the combination of age-related physiological changes in organ function, increased comorbid burden, and larger fluid shifts during more complex surgical procedures. The current state-of-the-art approach to fluid management in the perioperative period is outlined.

Effect of enhanced recovery after surgery on older patients undergoing transvaginal pelvic floor reconstruction surgery: a randomised controlled trial

BACKGROUND

Prospective trial evidence is lacking regarding the application of enhanced recovery after surgery (ERAS) in transvaginal pelvic floor reconstruction surgery among older patients. Our study aimed to investigate whether implementing the ERAS protocol could enhance post-operative recovery in this patient population.

METHODS

Older patients undergoing elective transvaginal pelvic floor reconstruction surgery were randomly assigned to either the ERAS group or the conventional group. The primary outcome was post-operative length of stay (LOS). The secondary outcomes encompassed other post-operative recovery metrics, post-operative pain within 30 days, the occurrence of complications, the peri-operative blood test and cognitive function.

RESULTS

A cohort of 100 patients was enrolled. Implementation of the ERAS protocol significantly reduced the duration of post-operative LOS (74.00 (69.00, 96.00) vs. 65.00 (59.00, 78.25) h, P < 0.01). Additionally, the ERAS protocol significantly reduced the duration of the first oral intake post-operatively (5.00 (2.50, 7.00) vs. 3.00 (2.00, 4.00) h, P = 0.01), and reduced rest and movement-related pain within 48 h post-operatively, effects that persisted through the 7-day follow-up period. It also shortened the duration of post-operative laryngeal mask airway support and promoted opioid-sparing. Moreover, the incidence and severity of post-operative nausea and vomiting (PONV) were significantly lower in the ERAS group compared to the conventional group at 12 h post-operatively.

CONCLUSIONS

Implementation of the ERAS protocol can expedite post-operative recovery in older patients undergoing transvaginal pelvic floor reconstruction surgery, achieve opioid-sparing, alleviate pain post-operatively, and decrease the incidence of complications.

TRIAL REGISTRATION

This study was retrospectively registered with the Chinese Clinical Trial Registry (registration number: ChiCTR2400084608). The date of first registration was 21/05/2024.

Incidence and factors associated with postoperative hemodynamic change in the postanaesthetic care unit among adult surgical patients at a tertiary care hospital in Ethiopia: a prospective observational study

BACKGROUND

Hemodynamic changes are independent risk factors for long-term patient morbidity and duration of hospital stay. According to the statistics, the three most prevalent complications in the postanaesthesia care unit were airway events, haemodynamic instability, and postoperative nausea and vomiting. Hemodynamic instability in the postanaesthesia care unit can result in serious complications, such as long-term patient morbidity and prolonged hospital stays. This study aimed to determine the incidence and factors associated with haemodynamic changes among adult surgical patients in the postanaesthetic care unit.

METHODS

An institution-based observational study was conducted from December 1, 2023, to June 30, 2024. In addition, 409 adult surgery patients participated. We employed consecutive sampling techniques and both analytical and descriptive statistics to explain our findings. Using both bivariable and multivariable logistic regression, we evaluated the strength of the association and determined the crude odds ratio and adjusted odds ratio with a 95% confidence interval. A p value of less than 0.05 was considered statistically significant in the multivariable regression.

RESULTS

The incidence of hemodynamic instability was 53.8% (CI: 45%, 64%). The incidences of hypotension, hypertension, tachycardia, and bradycardia were 24.2%, 17.45%, 31.3%, and 12.6%, respectively. ASA class III, procedures with more than 4 instances of intraoperative haemodynamic instability and neuraxial anaesthesia were significantly associated with haemodynamic instability in the postanaesthetic care unit.

CONCLUSION

In general, 93 study subjects (22.7%) experienced advanced haemodynamic instability during the intraoperative period. This implies that the incidence of hemodynamic instability was high. Intraoperative haemodynamic instability, American Society of Anaesthesiology class III, postoperative respiratory adverse events, neurologic and gynaecological procedures, use of neuraxial anaesthesia, and prolonged duration of procedures were predictors of haemodynamic instability in the postanaesthesia care unit.

Cerebral oximetry in high-risk surgical patients: where are we?

PURPOSE OF REVIEW

This review aims to summarize the latest evidence on the role of near-infrared spectroscopy (NIRS) in monitoring cerebral oxygenation in high-risk surgical patients, including both cardiac and noncardiac surgeries, and to present a new algorithm for its application.

RECENT FINDINGS

NIRS effectively measures brain oxygen saturation noninvasively, proving valuable in cardiac surgeries to reduce neurological complications, though its impact on nonneurological outcomes is less clear. In noncardiac surgeries, NIRS can help prevent complications like postoperative cognitive dysfunction, particularly in high-risk and major surgeries. Studies highlight the variability of cerebral oxygenation impacts based on surgical positions, with mixed results in positions like the beach chair and sitting positions. A structured algorithm for managing cerebral desaturation has been proposed to optimize outcomes by addressing multiple factors contributing to blood oxygen content and delivery.

SUMMARY

Despite its limitations, including spatial resolution and interindividual variability, NIRS is a useful tool for intraoperative cerebral monitoring. Further studies are needed to confirm its broader applicability in noncardiac surgeries, but current evidence supports its role in reducing postoperative complications especially in cardiac surgeries.

ERAS-Based Anesthetic Management of Patients Undergoing Abdominal-Based Free Flap Breast Reconstruction: A Narrative Review

Microsurgical breast reconstruction after mastectomy is emerging as the standard of care for patients with breast cancer. The enhanced recovery after surgery (ERAS) pathway in abdominal-based free flap breast reconstruction is in its early stage of development and lacks established consensus or guidelines. In the multidisciplinary ERAS team, the anesthesia sub-team is responsible for the provision of several core elements in the ERAS pathway including anesthetic protocol optimization, perioperative fluid management and homeostasis regulation, normothermia maintenance, perioperative analgesia, and postoperative nausea and vomiting prophylaxis. Here, we summarized the state-of-the-art in anesthetic practice for the patients undergoing abdominal-based free flap breast reconstruction within an ERAS framework, and also introduced the perioperative strategy for this surgical population based on the ERAS pathway in our center, aiming to improve free flap outcome and patient satisfaction, and accelerating their recovery following surgery.

Systematic review and meta-analysis of goal-directed haemodynamic therapy algorithms during surgery for the prevention of surgical site infection

Background

Surgical site infection (SSI) is the most common postoperative complication. Goal-directed haemodynamic therapy (GDHT) may help to prevent SSI, but recommendations for its use initially have been set at conditional because of low-certainty evidence at the time. An updated systematic review with SSI as the primary endpoint has not been performed since 2011, and important new evidence has emerged. We assessed the influence of GDHT on SSI and other postoperative outcomes.

Methods

We searched Ovid/MEDLINE, Excerpta Medica Database (Embase.com), and Cochrane library from inception up to September 2024 for randomised controlled trials comparing the effect of any GDHT algorithm to conventional fluid therapy on SSI incidence in adult patients undergoing surgery and analysed eligible data using random effects. We conducted several subgroup analyses, including the risk of bias (RoB), and a trial sequential analysis (TSA). We evaluated the certainty of evidence using Grading of Recommendations, Assessment, Development, and Evaluations. This study is registered with PROSPERO, CRD42022277535.

Findings

We found 75 studies that met the inclusion criteria with an incidence of 1,478 SSI among 13,010 patients (11.4%). The incidence of SSI was reduced from 13.3% in the conventional fluid therapy to 9.4% after GDHT (absolute risk reduction 3.9%); pooled relative risk 0.71 (95% CI 0.62-0.81). Subgroup analysis for the low RoB studies revealed comparable results. Meta-regression indicated no strong evidence for individual subgroup effects. In the TSA, the cumulative z-line crossed the boundary for effect.

Interpretation

High-certainty evidence indicates that GDHT reduces the risk of SSI when compared to conventional fluid therapy in adults undergoing surgery. New studies are unlikely to change this outcome. These findings justify a stronger recommendation for the use of GDHT.

Funding

Dutch Association for Quality Funds Medical Specialists.

Preoperative goal directed therapy in geriatric hip fracture patients - a retrospective quality improvement study

BACKGROUND

Hip fractures in older adults are common and carry a high risk of morbidity and mortality. Preoperative dehydration, a key risk factor for adverse outcomes, is often underdiagnosed at admission. It is important to identify high risk patients and optimize modifiable risk factors to improve the postoperative outcome. The p-POSSUM Score is a useful predictor of postoperative mortality risk. Implementing a defined fluid resuscitation protocol early in high-risk groups has proven effective in reducing both postoperative morbidity and mortality.

MATERIALS AND METHODS

We conducted a single-center, retrospective quality improvement study at a Level 1 trauma center in Switzerland, focusing on geriatric patients over 70 with a p-POSSUM Score > 5% and a proximal femur fracture, undergoing surgery between February 2015 and September 2019. We hypothesized that our institutional goal-directed fluid resuscitation protocol (GDT) would result in lower 30- and 90-day mortality rates and fewer complications for these high-risk patients. Outcome changes over time were analyzed annually.

RESULTS

312 patients were included in our study. 147 followed our institutional GDT protocol, while 165 patients received standard care and were used as a control group. Initially, the odds ratio (OR) for 30-days mortality favored the GDT group; 2015 0.30 (CI: 0.07-1.18), 2016 0.28 (CI: 0.07-1.07), 2017 0.51 (CI: 0.13-2.04). This shifted toward the Non-GDT group in the year 2018 with a OR of 2.14 (CI: 0.59-7.84) and 2019 with 1.92 (CI 0.47-7.83). The pattern for 90-day mortality results was similar and slightly more pronounced. The estimates for the odds ratios remained consistent even after adjustment for the p-POSSUM score. The relative frequencies of complications showed no remarkable differences between the groups (GDT vs. Non-GDT).

CONCLUSION

In our study, the treatment according to our GDT protocol was associated with survival advantage in the first three years. However, this trend reversed in 2018, with Non-GDT patients faring better. Although our retrospective study does not provide enough evidence of causality between the protocol and the mortality rates, it revealed that continuous critical evaluation of internal processes is essential in healthcare for quality management. This allows timely identification and adaptation of processes to issues, especially after initially positive results.

Effect of increased systemic oxygen delivery on postoperative outcomes and quality of life in elderly undergoing major abdominal surgery: A randomised controlled trial

Studies comparing the intentional increase in oxygen delivery and normal oxygen delivery during general anaesthesia in elderly patients undergoing major abdominal surgery are limited and have reported contradictory findings. Therefore, the study aimed to evaluate the effect of intraoperative increase in systemic oxygen delivery on postoperative outcomes and quality of life in elderly patients undergoing major abdominal surgery. This randomised, blinded, parallel-arm, pragmatic clinical trial included elderly patients of >60 years of age undergoing major abdominal surgery. The patients in the intervention arm received noradrenaline or increased fractional inspiration of oxygen to augment central venous oxygen saturation ⩾75%. The primary outcome measure was composite of in-hospital mortality and major organ complications. The secondary outcome measure included comparison of quality of life. A total of 160 patients were assessed for eligibility, and 146 were randomised in the study groups. The mean arterial and central venous oxygen saturation increased and were significantly higher in the intervention arm. The composite primary outcome occurred in 49.31% in the intervention arm and 57.53% in the usual care arm (relative risk; 95% confidence interval: 0.85; 0.63-1.16; absolute risk reduction; 8.22%; p = 0.32). Furthermore, quality of life at the end of three months was similar (0.658 ± 0.19 versus 0.647 ± 0.19; p = 0.771). In conclusion, central venous oxygen saturation-guided increase in systemic oxygen delivery during the intraoperative period of major abdominal surgery in elderly patients did not reduce predefined composite outcome of in-hospital mortality or organ-specific complications.

Critical care unit bed availability and postoperative outcomes: a multinational cohort study

BACKGROUND

Critical care beds are a limited resource, yet research indicates that recommendations for postoperative critical care admission based on patient-level risk stratification are not followed. It is unclear how prioritisation decisions are made in real-world settings and the effect of this prioritisation on outcomes.

METHODS

This was a prespecified analysis of an observational cohort study of adult patients undergoing inpatient surgery, conducted in 274 hospitals across the UK and Australasia during 2017. The primary outcome was postoperative morbidity at day 7. Logistic regression models were used to evaluate the relationship between critical care admission and patient and health system factors. The causal effect of critical care admission on outcome was estimated using variation in critical care occupancy as a natural experiment in an instrumental variable analysis.

RESULTS

A total of 19,491 patients from 248 hospitals were eligible for analysis, of whom 2107 were directly admitted to critical care postoperatively. Postoperative morbidity occurred in 2829/19,491 (15%) patients. Increasing surgical risk was associated with critical care admission, as was increased availability of critical care beds (odds ratio (95%CI) 1.04 (1.01-1.06), p = 0.002) per available bed; however, the probability of admission varied significantly between hospitals (median odds ratio 3.05). There was no evidence of a difference in postoperative morbidity with critical care admission (odds ratio (95%CI) 0.91 (0.57-1.45), p = 0.710).

DISCUSSION

Postoperative critical care admission is variable and related to bed availability. Statistical methods that adjust for unobserved confounding lowered the estimates of harm previously reported to have been associated with postoperative critical care admission. Our findings provide a rationale for a clinical trial which would evaluate any potential benefits for postoperative critical care admission for patients in whom there is no absolute indication for admission.

Association of velocity-pressure loop-derived values recorded during neurosurgical procedures with postoperative organ failure biomarkers: a retrospective single-center study

BACKGROUND

Perioperative renal and myocardial protection primarily depends on preoperative prediction tools, along with intraoperative optimization of cardiac output (CO) and mean arterial pressure (MAP). We hypothesise that monitoring the intraoperative global afterload angle (GALA), a proxy of ventricular afterload derived from the velocity pressure (VP) loop, could better predict changes in postoperative biomarkers than the recommended traditional MAP and CO.

METHOD

This retrospective monocentric study included patients programmed for neurosurgery with continuous VP loop monitoring. Patients with hemodynamic instability were excluded. Those presenting a 1-day post-surgery increase in creatinine, B-type natriuretic peptide, or troponin Ic us were labelled Bio+, Bio- otherwise. Demographics, intra-operative data, and comorbidities were considered as covariates. The study aimed to determine if intraoperative GALA monitoring could predict early postoperative biomarker disruption.

RESULT

From November 2018 to November 2020, 86 patients were analysed (Bio+/Bio- = 47/39). Bio+ patients were significantly older (62 [54-69] vs. 42 [34-57] years, p <  0.0001), More often hypertensive (25% vs. 9%, p = 0.009), and more frequently treated with antihypertensive drugs (31.9% vs. 7.7%, p = 0.013). GALA was significantly larger in Bio+ patients (40 [31-56] vs. 23 [19-29] °, p < 0.0001), while CO, MAP, and cumulative time spent <65mmHg were similar between groups. GALA exhibited strong predictive performances for postoperative biological deterioration (AUC = 0.88 [0.80-0.95]), significantly outperforming MAP (MAP AUC = 0.55 [0.43-0.68], p < 0.0001).

CONCLUSION

GALA under general anaesthesia prove more effective in detecting patients at risk of early cardiac or renal biological deterioration, compared to classical hemodynamic parameters.

The effect of intraoperative goal-directed fluid therapy in patients under anesthesia for gastrointestinal surgery

BACKGROUND

Intraoperative fluid management is an important aspect of anesthesia management in gastrointestinal surgery. Intraoperative goal-directed fluid therapy (GDFT) is a method for optimizing a patient's physiological state by monitoring and regulating fluid input in real-time.

AIM

To evaluate the efficacy of intraoperative GDFT in patients under anesthesia for gastrointestinal surgery.

METHODS

This study utilized a retrospective comparative study design and included 60 patients who underwent gastrointestinal surgery at a hospital. The experimental group (GDFT group) and the control group, each comprising 30 patients, received intraoperative GDFT and traditional fluid management strategies, respectively. The effect of GDFT was evaluated by comparing postoperative recovery, complication rates, hospitalization time, and other indicators between the two patient groups.

RESULTS

Intraoperative blood loss in the experimental and control groups was 296.64 ± 46.71 mL and 470.05 ± 73.26 mL (P < 0.001), and urine volume was 415.13 ± 96.72 mL and 239.15 ± 94.69 mL (P < 0.001), respectively. The postoperative recovery time was 5.44 ± 1.1 days for the experimental group compared to 7.59 ± 1.45 days (P < 0.001) for the control group. Hospitalization time for the experimental group was 10.87 ± 2.36 days vs 13.65 ± 3 days for the control group (P < 0.001). The visual analogue scale scores of the experimental and control groups at 24 h and 48 h post-surgery were 3.38 ± 0.79 and 4.51 ± 0.86, and 2.05 ± 0.57 and 3.51 ± 0.97 (P < 0.001), respectively. The cardiac output of the experimental and control groups was 5.99 ± 1.04 L/min and 4.88 ± 1.17 L/min, respectively, while the pulse pressure variability for these two groups was 10.87 ± 2.36% and 17.5 ± 3.21%, respectively.

CONCLUSION

The application of GDFT in gastrointestinal surgery can significantly improve postoperative recovery, reduce the incidence of complications, and shorten hospital stays.

Goal-Directed Fluid Therapy Using Pulse Pressure Variation in Thoracic Surgery Requiring One-Lung Ventilation: A Randomized Controlled Trial

Background: Intraoperative fluid management based on pulse pressure variation has shown potential to reduce postoperative pulmonary complications (PPCs) and improve clinical outcomes in various surgical settings. However, its efficacy and safety have not been assessed in patients undergoing thoracic surgery with one-lung ventilation. Methods: Patients scheduled for pulmonary lobectomy using uniportal video-assisted thoracic surgery approach were randomly assigned to two groups. In the PPV group, fluid administration was guided by the pulse pressure variation parameter, while in the near-zero group, it was guided by conventional hemodynamic parameters. The primary outcome was the partial pressure of oxygen (PaO2)/ fraction of inspired oxygen (FiO2) ratio 15 min after extubation. The secondary outcomes included extubation time, the incidence of postoperative pulmonary complications in the first three postoperative days, and the length of hospital stay. Results: The PaO2/FiO2 ratio did not differ between the two groups (364.48 ± 38.06 vs. 359.21 ± 36.95; p = 0.51), although patients in the PPV group (n = 44) received a larger amount of both crystalloids (1145 ± 470.21 vs. 890 ± 459.31, p = 0.01) and colloids (162.5 ± 278.31 vs 18.18 ± 94.68, p = 0.002) compared to the near-zero group (n = 44). No differences were found in extubation time, type and number of PPCs, and length of hospital stay. Conclusions: PPV-guided fluid management in thoracic surgery requiring one-lung ventilation does not improve pulmonary gas exchange as measured by the PaO2/FiO2 ratio and does not seem to offer clinical benefits. Additionally, it results in increased fluid administration compared to fluid management based on conventional hemodynamic parameters.

Predicting stroke volume variation using central venous pressure waveform: a deep learning approach

Objective. This study evaluated the predictive performance of a deep learning approach to predict stroke volume variation (SVV) from central venous pressure (CVP) waveforms.Approach. Long short-term memory (LSTM) and the feed-forward neural network were sequenced to predict SVV using CVP waveforms obtained from the VitalDB database, an open-source registry. The input for the LSTM consisted of 10 s CVP waveforms sampled at 2 s intervals throughout the anesthesia duration. Inputs of the feed-forward network were the outputs of LSTM and demographic data such as age, sex, weight, and height. The final output of the feed-forward network was the SVV. The performance of SVV predicted by the deep learning model was compared to SVV estimated derived from arterial pulse waveform analysis using a commercialized model, EV1000.Main results. The model hyperparameters consisted of 12 memory cells in the LSTM layer and 32 nodes in the hidden layer of the feed-forward network. A total of 224 cases comprising 1717 978 CVP waveforms and EV1000/SVV data were used to construct and test the deep learning models. The concordance correlation coefficient between estimated SVV from the deep learning model were 0.993 (95% confidence interval, 0.992-0.993) for SVV measured by EV1000.Significance. Using a deep learning approach, CVP waveforms can accurately approximate SVV values close to those estimated using commercial arterial pulse waveform analysis.

Reliability of Bioreactance and Pulse-Power Analysis in Measuring Cardiac Index During Open Abdominal Aortic Surgery

OBJECTIVE

To investigate the accuracy, precision, and trending ability of noninvasive bioreactance-based Starling SV and the mini invasive pulse-power device LiDCOrapid as compared to thermodilution cardiac output (TDCO) as measured by pulmonary artery catheter when assessing cardiac index (CIx) in the setting of elective open abdominal aortic (AA) surgery.

DESIGN

A prospective method-comparison study.

SETTING

Oulu University Hospital, Finland.

PARTICIPANTS

Forty patients undergoing elective open abdominal aortic surgery.

INTERVENTIONS

Intraoperative CI measurements were obtained simultaneously with TDCO and the study monitors, resulting in 627 measurement pairs with Starling SV and 497 with LiDCOrapid.

MEASUREMENTS AND MAIN RESULTS

The Bland-Altman method was used to investigate the agreement among the devices, and four-quadrant plots with error grids were used to assess trending ability. The agreement between TDCO and Starling SV was associated with a bias of 0.18 L/min/m2 (95% confidence interval [CI] = 0.13 to 0.23), wide limits of agreement (LOA = -1.12 to 1.47 L/min/m2), and a percentage error (PE) of 63.7 (95% CI = 52.4-71.0). The agreement between TDCO and LiDCOrapid was associated with a bias of -0.15 L/min/m2 (95% CI = -0.21 to -0.09), wide LOA (-1.56 to 1.37), and a PE of 68.7 (95% CI = 54.9-79.6). The trending ability of neither device was sufficient.

CONCLUSION

The CI measurements achieved with Starling SV and LiDCOrapid were not interchangeable with TDCO, and the ability to track changes in CI was poor. These results do not support the use of either study device in monitoring CI during open AA surgery.

Haemodynamic monitoring during noncardiac surgery: past, present, and future

During surgery, various haemodynamic variables are monitored and optimised to maintain organ perfusion pressure and oxygen delivery - and to eventually improve outcomes. Important haemodynamic variables that provide an understanding of most pathophysiologic haemodynamic conditions during surgery include heart rate, arterial pressure, central venous pressure, pulse pressure variation/stroke volume variation, stroke volume, and cardiac output. A basic physiologic and pathophysiologic understanding of these haemodynamic variables and the corresponding monitoring methods is essential. We therefore revisit the pathophysiologic rationale for intraoperative monitoring of haemodynamic variables, describe the history, current use, and future technological developments of monitoring methods, and finally briefly summarise the evidence that haemodynamic management can improve patient-centred outcomes.

How Would I Treat My Own Thoracoabdominal Aortic Aneurysm: Perioperative Considerations From the Anesthesiologist Perspective

A thoracoabdominal aortic aneurysm (TAAA) can be potentially life-threatening due to its associated risk of rupture. Thoracoabdominal aortic aneurysm repair, performed as endovascular repair and/or open surgery, is the recommended therapy of choice. Hemodynamic instability, severe blood loss, and spinal cord or cerebral ischemia are some potential hazards the perioperative team has to face during these procedures. Therefore, preoperative risk assessment and intraoperative anesthesia management addressing these potential hazards are essential to improving patients' outcomes. Based on a presented index case, an overview focusing on anesthetic measures to identify perioperatively and manage these risks in TAAA repair is provided.

Effect of Fluid Therapy in Early Morning on the Incidence of Post-Induction Hypotension During Non-Cardiac Surgery After Noon: A Single-Center Retrospective Study

Purpose

Post-induction hypotension (PIH) is a common clinical phenomenon linked to increased morbidity and mortality in various non-cardiac surgeries. Patients with surgery in the afternoon may have preoperative hypovolemia caused by prolonged fasting and dehydration, which increases the risk of hypotension during the induction period. However, studies on the fluid therapy in early morning combating PIH remain inadequate. Therefore, we aimed to investigate the influence of prophylactic high-volume fluid in the early morning of the operation day on the incidence of PIH during non-cardiac surgery after noon.

Patients and Methods

We reviewed the medical records of patients who underwent non-cardiac surgery after noon between October 2021 and October 2022. The patients were divided into two groups based on whether they received a substantial volume of intravenous fluid (high-volume group) or not (low-volume group) in the early morning of the surgery day. We investigated the incidence of PIH and intraoperative hypotension (IOH) as well as the accumulated duration of PIH in the first 15 minutes. In total, 550 patients were included in the analysis.

Results

After propensity score matching, the incidence of PIH was 39.7% in the high-volume group and 54.1% in the low-volume group. Multivariate logistic regression analysis showed that patients in the high-volume group had lower incidence of hypotension after induction compared with the low-volume group (odds ratio, 0.55; 95% CI, 0.34-0.89; p = 0.016). The high-volume fluid infusion in the preoperative morning was significantly correlated with the decreased duration of PIH (p = 0.013), but no statistical difference was observed for the occurrence of IOH between the two groups (p = 0.075).

Conclusion

The fluid therapy of more than or equal to 1000 mL in the early morning of the surgery day was associated with a decreased incidence of PIH compared with the low-volume group in patients undergoing non-cardiac surgery after noon.

Randomized Prospective Trial of Epidural Analgesia after Open Hepatectomy

OBJECTIVE

To evaluate whether patient-controlled epidural analgesia (PCEA) improves postoperative pain during ambulation following elective open hepatectomy.

BACKGROUND

Strategies to alleviate postoperative pain are a critical element of recovery after surgery. However, the optimal postoperative pain management strategy following open hepatectomy remains unclear.

METHODS

We conducted a prospective, nonblinded, randomized comparison of PCEA (intervention) versus intravenous patient-controlled analgesia (IV PCA; control) for postoperative pain following elective open hepatectomy. The primary end point was pain during ambulation on postoperative day (POD) 2. The study was powered to detect a clinically significant 2-point difference on the pain numeric rating scale (NRS). Secondary end points included pain at rest, morbidity, time to return of bowel function, and length of stay.

RESULTS

From 2015 to 2020, 231 patients were randomized (116 patients in the PCEA arm and 115 in the IV PCA arm). The incidence of epidural failure was 3% (n=4/116), with no epidural-related complications. Patients in the PCEA arm had a <2-point difference in NRS pain scores during ambulation on POD 2 vs. IV PCA (median 4.0 vs. 5.0, P <0.001). There was no difference in overall complications between the PCEA and IV PCA arms (33% vs. 40%, P =0.276). Secondary outcomes, including pain scores at rest, were similar between the study arms.

CONCLUSIONS

PCEA was safe following open hepatectomy and was associated with a small difference in pain with activity on POD 2 that did not reach our pre-specified definition of clinical significance.

Feasibility of Goal-Directed Fluid Therapy in Patients with Transcatheter Aortic Valve Replacement - An Ambispective Analysis

INTRODUCTION

Goal-directed fluid therapy (GDFT) has been shown to reduce postoperative complications. The feasibility of GDFT in transcatheter aortic valve replacement (TAVR) patients under general anesthesia has not yet been demonstrated. We examined whether GDFT could be applied in patients undergoing TAVR in general anesthesia and its impact on outcomes.

METHODS

Forty consecutive TAVR patients in the prospective intervention group with GDFT were compared to 40 retrospective TAVR patients without GDFT. Inclusion criteria were age ≥ 18 years, elective TAVR in general anesthesia, no participation in another interventional study. Exclusion criteria were lack of ability to consent study participation, pregnant or nursing patients, emergency procedures, preinterventional decubitus, tissue and/or extremity ischemia, peripheral arterial occlusive disease grade IV, atrial fibrillation or other severe heart rhythm disorder, necessity of usage of intra-aortic balloon pump. Stroke volume and stroke volume variation were determined with uncalibrated pulse contour analysis and optimized according to a predefined algorithm using 250 ml of hydroxyethyl starch.

RESULTS

Stroke volume could be increased by applying GDFT. The intervention group received more colloids and fewer crystalloids than control group. Total volume replacement did not differ. The incidence of overall complications as well as intensive care unit and hospital length of stay were comparable between both groups. GDFT was associated with a reduced incidence of delirium. Duration of anesthesia was shorter in the intervention group. Duration of the interventional procedure did not differ.

CONCLUSION

GDFT in the intervention group was associated with a reduced incidence of postinterventional delirium.

Impact of Intra-Operative Shock and Resuscitation on Surgical Site Infections After Trauma Laparotomy

Background: Patients undergoing trauma laparotomy experience high rates of surgical site infection (SSI). Although intra-operative shock is a likely contributor to SSI risk, little is known about the relation between shock, intra-operative restoration of physiologic normalcy, and SSI development. Patients and Methods: A retrospective review of trauma patients who underwent emergent definitive laparotomy was performed. Using shock index and base excess at the beginning and end of laparotomy, patients were classified as normal, persistent shock, resuscitated, or new shock. Univariable and multivariable analyses were performed to identify predictors of organ/space SSI, superficial/deep SSI, and any SSI. Results: Of 1,191 included patients, 600 (50%) were categorized as no shock, 248 (21%) as resuscitated, 109 (9%) as new shock, and 236 (20%) as persistent shock, with incidence of any SSI as 51 (9%), 28 (11%), 26 (24%), and 32 (14%), respectively. These rates were similar in organ/space and superficial/deep SSIs. On multivariable analysis, resuscitated, new shock, and persistent shock were associated with increased odds of organ/space SSI (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.3-3.5; p < 0.001) and any SSI (OR, 2.0; 95% CI, 1.4-3.2; p < 0.001), but no increased risk of superficial/deep SSI (OR, 1.4; 95% CI, 0.8-2.6; p = 0.331). Conclusions: Although the trajectory of physiologic status influenced SSI, the presence of shock at any time during trauma laparotomy, regardless of restoration of physiologic normalcy, was associated with increased odds of SSI. Further investigation is warranted to determine the relation between peri-operative shock and SSI in trauma patients.

A systematic review and meta-analysis on the effect of goal-directed fluid therapy on postoperative outcomes in renal transplantation surgeries

Introduction

This systematic review and meta-analysis investigated the impact of intraoperative goal-directed therapy (GDT) compared with conventional fluid therapy on postoperative outcomes in renal transplantation recipients, addressing this gap in current literature.

Method

A systematic search of patients aged ≥18 years who have undergone single-organ primary renal transplantations up to June 2022 in PubMed, Embase, Scopus and CINAHL Plus was performed. Primary outcome examined was postoperative renal function. Secondary outcomes assessed were mean arterial pressure at graft reperfusion, intraoperative fluid volume and other postoperative complications. Heterogeneity was tested using I² test. The study protocol was registered on PROSPERO.

Results

A total of 2459 studies were identified. Seven eligible studies on 607 patients were included. Subgroup assessments revealed potential renal protective benefits of GDT, with patients receiving cadaveric grafts showing lower serum creatinine on postoperative days 1 and 3, and patients monitored with arterial waveform analysis devices experiencing lower incidences of postoperative haemodialysis. Overall analysis found GDT resulted in lower incidence of tissue oedema (risk ratio [RR] 0.34, 95% CI 0.15-0.78, P=0.01) and respiratory complications (RR 0.39, 95% CI 0.17-0.90, P=0.03). However, quality of data was deemed low given inclusion of non-randomised studies, presence of heterogeneities and inconsistencies in defining outcomes measures.

Conclusion

While no definitive conclusions can be ascertained given current limitations, this review highlights potential benefits of using GDT in renal transplantation recipients. It prompts the need for further standardised studies to address limitations discussed in this review.

The impact of perioperative fluid therapy on the short-term outcomes after laparoscopic colorectal cancer surgery with ERAS protocol: a prospective observational study

The main goals of the Enhanced recovery after surgery (ERAS) protocol are focused on shortening the length of hospital stay (LOS), expediting convalescence, and reducing morbidity. A balanced perioperative fluid therapy is among the significant interventions incorporated by the ERAS protocol. The article contains extensive discussion surrounding the impact of this individual intervention on short-term outcomes. The aim of this study was to assess the impact of perioperative fluid therapy on short-term outcomes in patients after laparoscopic colorectal cancer surgery. The analysis included consecutive patients, who had undergone laparoscopic colorectal cancer operations between 2013 and 2020. Patients were divided into two groups: restricted (≤ 2500 ml) or excessive (> 2500 ml) perioperative fluid therapy. A standardized ERAS protocol was implemented in all patients. The study outcomes included recovery parameters and the morbidity rate, LOS and 30 days readmission rate. There were 361 and 80 patients in groups 1 and 2, respectively. There were no statistically significant differences between the groups in terms of demographic parameters and factors related to the surgical procedure. Logistic regression showed that restricted fluid therapy as a single intervention was associated with improvement in tolerance of diet on 1st postoperative day (OR 2.18, 95% CI 1.31-3.62, p = 0.003), accelerated mobilization on 1st postoperative day (OR 2.43, 95% CI 1.29-4.61, p = 0.006), lower risk of postoperative morbidity (OR 0.58, 95%CI 0.36-0.98, p = 0.046), shorter LOS (OR 0.49, 95% CI 0.29-0.81, p = 0.005) and reduced readmission rate (OR 0.48, 95% CI 0.23-0.98, p = 0.045). A balanced perioperative fluid therapy on the day of surgery may be associated with faster convalescence, lower morbidity rate, shorter LOS and lower 30 days readmission rate.

Clinical outcomes of a prospective randomized comparison of bioreactance monitoring versus pulse-contour analysis in a stroke-volume based goal-directed fluid resuscitation protocol in brain-dead organ donors

Eighty percent of brain-dead (BD) organ donors develop hypotension and are frequently hypovolemic. Fluid resuscitation in a BD donor is controversial. We have previously published our 4-h goal-directed stroke volume (SV)-based fluid resuscitation protocol which significantly decreased time on vasopressors and increased transplanting four or more organs. The SV was measured by pulse-contour analysis (PCA) or an esophageal doppler monitor, both of which are invasive. Thoracic bioreactance (BR) is a non-invasive portable technology that measures SV but has not been studied in BD donors. We performed a randomized prospective comparative study of BR versus PCA technology in our fluid resuscitation protocol in BD donors. Eighty-four donors (53.1%) were randomized to BR and 74 donors to PCA (46.8%). The two groups were well matched based on 24 demographic, social, and initial laboratory factors, without any significant differences between them. There was no difference in the intravenous fluid infused over the 4-h study period [BR 2271 ± 823 vs. PCA 2230 ± 962 mL; p = .77]. There was no difference in the time to wean off vasopressors [BR 108.8 ± 61.8 vs. PCA 150.0 ± 68 min p = .07], nor in the number of donors off vasopressors at the end of the protocol [BR 16 (28.6%) vs. PCA 15 (29.4%); p = .92]. There was no difference in the total number of organs transplanted per donor [BR 3.25 ± 1.77 vs. PCA 3.22 ± 1.75; p = .90], nor in any individual organ transplanted. BR was equivalent to PCA in clinical outcomes and provides a simple, non-invasive, portable technology to monitor fluid resuscitation in organ donors.

The Effect of Goal-directed Fluid Management based on Stroke Volume Variation on ICU Length of Stay in Elderly Patients Undergoing Elective Craniotomy: A Randomized Controlled Trial

Background

Inappropriate fluid management during neurosurgery can increase postoperative complications. In this study, we aimed to investigate the effect of goal-directed fluid therapy using stroke volume variation (SVV) in elderly patients undergoing elective craniotomy.

Materials and methods

We randomized 100 elderly patients scheduled for elective craniotomy into two groups: goal-directed therapy (GDT, n = 50) group and conventional group (n = 50). Fluid management protocol using SVV was applied in the GDT group. Decisions about fluid and hemodynamic management in the conventional group were made by the anesthesiologist. Perioperative variables including fluid balance, lactate level, and intensive care unit (ICU) length of stay were assessed.

Results

There was no significant difference in ICU length of stay between the two groups: 14 (12, 16.75) hours in GDT group vs 15 (13, 18) hours in control group (p = 0.116). Patients in the GDT group received a significantly less amount of crystalloid compared with the control group: 1311.5 (823, 2018) mL vs 2080 (1420, 2690) mL (p < 0.001). Our study demonstrated a better fluid balance in the GDT group as 342.5 (23, 607) mL compared with the conventional group 771 (462, 1269) mL (p < 0.001).

Conclusion

Intraoperative goal-directed fluid management based on SVV in elderly patients undergoing elective craniotomy did not reduce the ICU length of stay or postoperative complications. It did result in an improved fluid balance with no evidence of inadequate organ perfusion.

Clinical trial registration number

TCTR20190812003.

How to cite this article

Sae-Phua V, Tanasittiboon S, Sangtongjaraskul S. The Effect of Goal-directed Fluid Management based on Stroke Volume Variation on ICU Length of Stay in Elderly Patients Undergoing Elective Craniotomy: A Randomized Controlled Trial. Indian J Crit Care Med 2023;27(10):709-716.

Perioperative Fluid Management

The medical complexity of the geriatric patients has been steadily rising. Still, as outcomes of surgical procedures in the elderly are improving, centers are pushing boundaries. There is also a growing appreciation of the importance of perioperative fluid management on postoperative outcomes, especially in the elderly. Optimal fluid management in this cohort is challenging due to the combination of age-related physiological changes in organ function, increased comorbid burden, and larger fluid shifts during more complex surgical procedures. The current state-of-the-art approach to fluid management in the perioperative period is outlined.

Tidal volume challenge-induced hemodynamic changes can predict fluid responsiveness during one-lung ventilation: an observational study

Background

To evaluate the ability of tidal volume challenge (VTC)-induced hemodynamic changes to predict fluid responsiveness in patients during one-lung ventilation (OLV).

Methods

80 patients scheduled for elective thoracoscopic surgery with OLV were enrolled. The inclusion criteria were: age ≥ 18 years, American Society of Anesthesiologists physical status I-III, normal right ventricular function, normal left ventricular systolic function (ejection fraction ≥55%), and normal or slightly impaired diastolic function. The study protocol was implemented 15 min after starting OLV. Simultaneous recordings were performed for hemodynamic variables of diameter of left ventricular outflow tract, velocity time integral (VTI) of aortic valve, and stroke volume (SV), and ΔSV-VTC, ΔVTI-VTC, and ΔMAP-VTC were calculated at four time points: with VT 5 mL/kg (T1); after VT increased from 5 mL/kg to 8 mL/kg and maintained at this level for 2 min (T2); after VT was adjusted back to 5 mL/kg for 2 min (T3); and after volume expansion (250 mL of 0.9% saline infused over 10-15 min) (T4). Patients were considered as responders to fluid administration if SV increased by ≥10%. Receiver operating characteristic (ROC) curves for percent decrease in SV, VTI, and MAP by VTC were generated to evaluate their ability to discriminate fluid responders from nonresponders.

Results

Of the 58 patients analyzed, there were 32 responders (55%) and 26 nonresponders (45%). The basic characteristics were comparable between the two groups (p > 0.05). The area under the curve (AUC) for ΔSV-VTC, ΔVTI-VTC, and ΔMAP-VTC to discriminate responders from nonresponders were 0.81 (95% CI: 0.68-0.90), 0.79 (95% CI: 0.66-0.89), and 0.56 (95% CI: 0.42-0.69). The best threshold for ΔSV-VTC was -16.1% (sensitivity, 78.1%; specificity, 84.6%); the best threshold for ΔVTI-VTC was -14.5% (sensitivity, 78.1%; specificity, 80.8%).

Conclusion

Tidal volume challenge-induced relative change of stroke volume and velocity time integral can predict fluid responsiveness in patients during one-lung ventilation.Clinical Trial Registration: Chinese Clinical Trial Registry, No: chictr210051310.

Prediction of postoperative patient deterioration and unanticipated intensive care unit admission using perioperative factors

BACKGROUND AND OBJECTIVES

Currently, no evidence-based criteria exist for decision making in the post anesthesia care unit (PACU). This could be valuable for the allocation of postoperative patients to the appropriate level of care and beneficial for patient outcomes such as unanticipated intensive care unit (ICU) admissions. The aim is to assess whether the inclusion of intra- and postoperative factors improves the prediction of postoperative patient deterioration and unanticipated ICU admissions.

METHODS

A retrospective observational cohort study was performed between January 2013 and December 2017 in a tertiary Dutch hospital. All patients undergoing surgery in the study period were selected. Cardiothoracic surgeries, obstetric surgeries, catheterization lab procedures, electroconvulsive therapy, day care procedures, intravenous line interventions and patients under the age of 18 years were excluded. The primary outcome was unanticipated ICU admission.

RESULTS

An unanticipated ICU admission complicated the recovery of 223 (0.9%) patients. These patients had higher hospital mortality rates (13.9% versus 0.2%, p<0.001). Multivariable analysis resulted in predictors of unanticipated ICU admissions consisting of age, body mass index, general anesthesia in combination with epidural anesthesia, preoperative score, diabetes, administration of vasopressors, erythrocytes, duration of surgery and post anesthesia care unit stay, and vital parameters such as heart rate and oxygen saturation. The receiver operating characteristic curve of this model resulted in an area under the curve of 0.86 (95% CI 0.83-0.88).

CONCLUSIONS

The prediction of unanticipated ICU admissions from electronic medical record data improved when the intra- and early postoperative factors were combined with preoperative patient factors. This emphasizes the need for clinical decision support tools in post anesthesia care units with regard to postoperative patient allocation.

Evaluation of Electrical Cardiometry for Measuring Cardiac Output and Derived Hemodynamic Variables in Comparison with Lithium Dilution in Anesthetized Dogs

Numerous cardiac output (CO) technologies were developed to replace the 'gold standard' pulmonary artery thermodilution due to its invasiveness and the risks associated with it. Minimally invasive lithium dilution (LiD) shows excellent agreement with thermodilution and can be used as a reference standard in animals. This study evaluated CO via noninvasive electrical cardiometry (EC) and acquired hemodynamic variables against CO measured using LiD in six healthy, anesthetized dogs administered different treatments (dobutamine, esmolol, phenylephrine, and high-dose isoflurane) impacting CO values. These treatments were chosen to cause drastic variations in CO, so that fair comparisons between EC and LiD across a wide range of CO values (low, intermediate, and high) could be made. Statistical analysis included linear regression, Bland-Altman plots, Lin's concordance correlation coefficient (ρ_c), and polar plots. Values of p < 0.05 represented significance. Good agreement was observed between EC and LiD, but consistent underestimation was noted when the CO values were high. The good trending ability, ρ_c of 0.88, and low percentage error of ±31% signified EC's favorable performance. Other EC-acquired variables successfully tracked changes in CO measured using LiD. EC may be a pivotal hemodynamic tool for continuously monitoring circulatory changes, as well as guiding and treating cardiovascular anesthetic complications in clinical settings.

Effects of goal-directed fluid management guided by a non-invasive device on the incidence of postoperative complications in neurosurgery: a pilot and feasibility randomized controlled trial

BACKGROUND

The positive effects of goal-directed hemodynamic therapy (GDHT) on patient-orientated outcomes have been demonstrated in various clinical scenarios; however, the effects of fluid management in neurosurgery remain unclear. Therefore, this study was aimed at assessing the safety and feasibility of GDHT using non-invasive hemodynamic monitoring in elective neurosurgery. The incidence of postoperative complications was compared between GDHT and control groups.

METHODS

We conducted a single-center randomized pilot study with an enrollment target of 34 adult patients scheduled for elective neurosurgery. We randomly assigned the patients equally into control and GDHT groups. The control group received standard therapy during surgery and postoperatively, whereas the GDHT group received therapy guided by an algorithm based on non-invasive hemodynamic monitoring. In the GDHT group, we aimed to achieve and sustain an optimal cardiac index by using non-invasive hemodynamic monitoring and bolus administration of colloids and vasoactive drugs. The number of patients with adverse events, feasibility criteria, perioperative parameters, and incidence of postoperative complications was compared between groups.

RESULTS

We successfully achieved all feasibility criteria. The GDHT protocol was safe, because no patients in either group had unsatisfactory brain tissue relaxation after surgery or brain edema requiring therapy during surgery or 24 h after surgery. Major complications occurred in two (11.8%) patients in the GDHT group and six (35.3%) patients in the control group (p = 0.105).

CONCLUSIONS

Our results suggested that a large randomized trial evaluating the effects of GDHT on the incidence of postoperative complications in elective neurosurgery should be safe and feasible. The rate of postoperative complications was comparable between groups.

TRIAL REGISTRATION

Trial registration: ClininalTrials.gov, registration number: NCT04754295, date of registration: February 15, 2021.

Intraoperative pleth variability index-based fluid management therapy and gastrointestinal surgical outcomes in elderly patients: a randomised controlled trial

BACKGROUND

Intraoperative goal-directed fluid therapy (GDFT) has been reported to reduce postoperative complications of patients undergoing major abdominal surgery. The clinical benefits of pleth variability index (PVI)-directed fluid management for gastrointestinal (GI) surgical patients remain unclear. Therefore, this study aimed to evaluate the impact of PVI-directed GDFT on GI surgical outcomes in elderly patients.

METHODS

This randomised controlled trial was conducted in two university teaching hospitals from November 2017 to December 2020. In total, 220 older adults undergoing GI surgery were randomised to the GDFT or conventional fluid therapy (CFT) group (n = 110 each). The primary outcome was a composite of complications within 30 postoperative days. The secondary outcomes were cardiopulmonary complications, time to first flatus, postoperative nausea and vomiting, and postoperative length of stay.

RESULTS

The total volumes of fluid administered were less in the GDFT group than in the CFT group (2.075 L versus [vs.] 2.5 L, P = 0.008). In intention-to-treat analysis, there was no difference in overall complications between the CFT group (41.3%) and GDFT group (43.0%) (odds ratio [OR] = 0.935; 95% confidence interval [CI], 0.541-1.615; P = 0.809). The proportion of cardiopulmonary complications was higher in the CFT group than in the GDFT group (19.2% vs. 8.4%; OR = 2.593, 95% CI, 1.120-5.999; P = 0.022). No other differences were identified between the two groups.

CONCLUSIONS

Among elderly patients undergoing GI surgery, intraoperative GDFT based on the simple and non-invasive PVI did not reduce the occurrence of composite postoperative complications but was associated with a lower cardiopulmonary complication rate than usual fluid management.

TRIAL REGISTRATION

This trial was registered with the Chinese Clinical Trial Registry (ChiCTR-TRC-17012220) on 1 August 2017.

Goal-directed fluid therapy using uncalibrated pulse contour analysis and balanced crystalloid solutions during hip revision arthroplasty: a quality implementation project

BACKGROUND

To implement a goal-directed fluid therapy (GDFT) protocol using crystalloids in hip revision arthroplasty surgery within a quality management project at a tertiary hospital using a monocentric, prospective observational study.

METHODS

Adult patients scheduled for elective hip revision arthroplasty surgery were screened for inclusion in this prospective study. Intraoperatively stroke volume (SV) was optimized within a previously published protocol using uncalibrated pulse contour analysis and balanced crystalloids. Quality of perioperative GDFT was assessed by protocol adherence, SV increase as well as the rate of perioperative complications. Findings were then compared to two different historical groups of a former trial: one receiving GDFT with colloids (prospective colloid group) and one standard fluid therapy (retrospective control group) throughout surgery. Statistical analysis constitutes exploratory data analyses and results are expressed as median with 25th and 75th percentiles, absolute and relative frequencies, and complication rates are further given with 95% confidence intervals for proportions using the normal approximation without continuity correction.

RESULTS

Sixty-six patients underwent GDFT using balanced crystalloids and were compared to 130 patients with GDFT using balanced colloids and 130 controls without GDFT fluid resuscitation. There was a comparable increase in SV (crystalloids: 65 (54-74 ml; colloids: 67.5 (60-75.25 ml) and total volume infused (crystalloids: 2575 (2000-4210) ml; colloids: 2435 (1760-3480) ml; and controls: 2210 (1658-3000) ml). Overall perioperative complications rates were similar (42.4% (95%CI 30.3-55.2%) for crystalloids and 49.2% (95%CI 40.4-58.1%) for colloids and lower compared to controls: 66.9% (95%CI 58.1-74.9)). Interestingly, a reduced number of hemorrhagic complications was observed within crystalloids: 30% (95%CI 19.6-42.9); colloids: 43% (95%CI 34.4-52.0); and controls: 62% (95%CI 52.6-69.9). There were no differences in the rate of admission to the post-anesthesia care unit or intensive care unit as well as the length of stay.

CONCLUSIONS

Perioperative fluid management using a GDFT protocol with crystalloids in hip revision arthroplasty surgery was successfully implemented in daily clinical routine. Perioperative complications rates were reduced compared to a previous management without GDFT and comparable when using colloids.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01753050.

Agreement between cardiac output estimation by multi-beat analysis of arterial blood pressure waveforms and continuous thermodilution in post cardiac surgery intensive care unit patients

We sought to assess agreement of cardiac output estimation between continuous pulmonary artery catheter (PAC) guided thermodilution (CO-CTD) and a novel pulse wave analysis (PWA) method that performs an analysis of multiple beats of the arterial blood pressure waveform (CO-MBA) in post-operative cardiac surgery patients. PAC obtained CO-CTD measurements were compared with CO-MBA measurements from the Argos monitor (Retia Medical; Valhalla, NY, USA), in prospectively enrolled adult cardiac surgical intensive care unit patients. Agreement was assessed via Bland-Altman analysis. Subgroup analysis was performed on data segments identified as arrhythmia, or with low CO (less than 5 L/min). 927 hours of monitoring data from 79 patients was analyzed, of which 26 had arrhythmia. Mean CO-CTD was 5.29 ± 1.14 L/min (bias ± precision), whereas mean CO-MBA was 5.36 ± 1.33 L/min, (4.95 ± 0.80 L/min and 5.04 ± 1.07 L/min in the arrhythmia subgroup). Mean of differences was 0.04 ± 1.04 L/min with an error of 38.2%. In the arrhythmia subgroup, mean of differences was 0.14 ± 0.90 L/min with an error of 35.4%. In the low CO subgroup, mean of differences was 0.26 ± 0.89 L/min with an error of 40.4%. In adult patients after cardiac surgery, including those with low cardiac output and arrhythmia CO-MBA is not interchangeable with the continuous thermodilution method via a PAC, when using a 30% error threshold.

Goal-directed haemodynamic therapy: an imprecise umbrella term to avoid

'Goal-directed haemodynamic therapy' describes various haemodynamic treatment strategies that have in common that interventions are titrated to achieve predefined haemodynamic targets. However, the treatment strategies differ substantially regarding the underlying haemodynamic target variables and target values, and thus presumably have different effects on outcome. It is an over-simplifying approach to lump complex and substantially differing haemodynamic treatment strategies together under the term 'goal-directed haemodynamic therapy', an imprecise umbrella term that we should thus stop using.

Stroke Volume and Arterial Pressure Fluid Responsiveness in Patients With Elevated Stroke Volume Variation Undergoing Major Vascular Surgery: A Prospective Intervention Study

OBJECTIVES

The identification of potential hemodynamic indicators to increase the predictive power of stroke-volume variation (SVV) for mean arterial pressure (MAP) and stroke volume (SV) fluid responsiveness.

DESIGN

A prospective intervention study.

SETTING

At a single-center university hospital.

PARTICIPANTS

Nineteen patients during major vascular surgery with 125 fluid interventions.

INTERVENTIONS

When SVV ≥13% occurred for >30 seconds, 250 mL of Ringer's lactate were given within 2 minutes.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic variables, such as pulse-pressure variation (PPV) and dynamic arterial elastance (Edyn), were measured by pulse power-wave analysis. The outcomes were MAP and SV responsiveness, defined as an increase of at least 10% of MAP and SV within 5 minutes of the fluid intervention. Of the fluid interventions, 48% were MAP-responsive, and 66% were SV-responsive. The addition of PPV and Edyn cut-off values to the SVV cut-off decreased sensitivity from 1-to-0.66 to-0.82, and concomitantly increased specificity from 0-to- 0.65-to-0.93 for the prediction of MAP and SV responsiveness in the authors' study setting. The areas under the receiver operating characteristic curves of PPV and Edyn for the prediction of MAP responsiveness were 0.79 and 0.75, respectively. The areas under the receiver operating characteristic curves for PPV and Edyn to predict SV responsiveness were 0.85 and 0.77, respectively.

CONCLUSIONS

The PPV and Edyn showed good accuracy for the prediction of MAP and SV responsiveness in patients with elevated SVV during vascular surgery. Either PPV or Edyn may be used in conjunction with SVV to better predict MAP and SV fluid responsiveness in patients undergoing vascular surgery.

Emerging Concepts Impacting Head and Neck Cancer Surgery Morbidity

All treatment modalities for head and neck cancer carry with them a risk of adverse events. Head and neck surgeons are faced with significant challenges to minimize associated morbidity and manage its sequelae. Recognizing situations in which a surgical complication is an adverse event inherent to the procedure can alleviate the psychologic impact a complication might have on the treatment team and minimize external and internal pressures. Focusing on the complications that can be effectively modified, future complications can be avoided. Also, some surgical morbidities may not be preventable, necessitating the option to reconsider whether the incidents should be labeled toxic reactions rather than a complication. This discussion highlights some of the areas in which additional research is needed to achieve the goal of minimizing the impact of surgical morbidity.

Non-invasive assessment of Pulse Wave Transit Time (PWTT) is a poor predictor for intraoperative fluid responsiveness: a prospective observational trial (best-PWTT study)

BACKGROUND

Aim of this study is to test the predictive value of Pulse Wave Transit Time (PWTT) for fluid responsiveness in comparison to the established fluid responsiveness parameters pulse pressure (ΔPP) and corrected flow time (FTc) during major abdominal surgery.

METHODS

Forty patients undergoing major abdominal surgery were enrolled with continuous monitoring of PWTT (LifeScope® Modell J BSM-9101 Nihon Kohden Europe GmbH, Rosbach, Germany) and stroke volume (Esophageal Doppler Monitoring CardioQ-ODM®, Deltex Medical Ltd, Chichester, UK). In case of hypovolemia (difference in pulse pressure [∆PP] ≥ 9%, corrected flow time [FTc] ≤ 350 ms) a fluid bolus of 7 ml/kg ideal body weight was administered. Receiver operating characteristics (ROC) curves and corresponding areas under the curve (AUCs) were used to compare different methods of determining PWTT. A Wilcoxon test was used to discriminate fluid responders (increase in stroke volume of ≥ 10%) from non-responders. The predictive value of PWTT for fluid responsiveness was compared by testing for differences between ROC curves of PWTT, ΔPP and FTc using the methods by DeLong.

RESULTS

AUCs (area under the ROC-curve) to predict fluid responsiveness for PWTT-parameters were 0.61 (raw c finger Q), 0.61 (raw c finger R), 0.57 (raw c ear Q), 0.53 (raw c ear R), 0.54 (raw non-c finger Q), 0.52 (raw non-c finger R), 0.50 (raw non-c ear Q), 0.55 (raw non-c ear R), 0.63 (∆ c finger Q), 0.61 (∆ c finger R), 0.64 (∆ c ear Q), 0.66 (∆ c ear R), 0.59 (∆ non-c finger Q), 0.57 (∆ non-c finger R), 0.57 (∆ non-c ear Q), 0.61 (∆ non-c ear R) [raw measurements vs. ∆ = respiratory variation; c = corrected measurements according to Bazett's formula vs. non-c = uncorrected measurements; Q vs. R = start of PWTT-measurements with Q- or R-wave in ECG; finger vs. ear = pulse oximetry probe location]. Hence, the highest AUC to predict fluid responsiveness by PWTT was achieved by calculating its respiratory variation (∆PWTT), with a pulse oximeter attached to the earlobe, using the R-wave in ECG, and correction by Bazett's formula (AUC best-PWTT 0.66, 95% CI 0.54-0.79). ∆PWTT was sufficient to discriminate fluid responders from non-responders (p = 0.029). No difference in predicting fluid responsiveness was found between best-PWTT and ∆PP (AUC 0.65, 95% CI 0.51-0.79; p = 0.88), or best-PWTT and FTc (AUC 0.62, 95% CI 0.49-0.75; p = 0.68).

CONCLUSION

ΔPWTT shows poor ability to predict fluid responsiveness intraoperatively. Moreover, established alternatives ΔPP and FTc did not perform better.

TRIAL REGISTRATION

Prior to enrolement on clinicaltrials.gov (NC T03280953; date of registration 13/09/2017).

Changes in transcranial near-infrared spectroscopy values reflect changes in cardiac index during cardiac surgery

To determine whether changes in transcranial near-infrared spectroscopy (NIRS) values reflect changes in cardiac index (CI) in adult cardiac surgical patients. Single-center prospective post hoc analysis. University hospital. One hundred and twenty-four adult patients undergoing cardiac surgery. In each patient, several CI measurements were taken, and NIRS values were collected simultaneously. We used a hierarchical linear regression model to assess the association between NIRS values and CI. We calculated a crude model with NIRS as the only factor included, and an adjusted model, where mean arterial pressure, end-tidal CO₂ , and oxygen saturation were used as confounding factors. A total of 1301 pairs of NIRS and CI values were collected. The analysis of separate NIRS and CI pairs revealed a poor association, which was not statistically significant when adjusted with the chosen confounders. However, when the changes in NIRS from baseline or from the previous measurement were compared to those of CI, a clinically and statistically significant association between NIRS and CI was observed also in the adjusted model. Compared to the baseline and to the previous measurement, respectively, the regression coefficients with 95% confidence intervals were 0.048 (0.041-0.056) and 0.064 (0.055-0.073) in off-pump coronary artery bypass patients and 0.022 (0.016-0.029) and 0.026 (0.020-0.033) in patients who underwent cardiopulmonary bypass. In an unselected cardiac surgical population, the changes in NIRS values reflect those in CI, especially in off-pump coronary artery bypass patients. In this single-center post hoc analysis of data from a prospectively collected database of cardiac surgery patients, paired measurements of cardiac output and NIRS revealed that while there was a no correlation between individual paired measurements, a small correlation was found in changes in the two measurements from baseline values. This highlights a potential to utilize changes in NIRS from baseline to suggest changes in cardiac output in cardiac surgical populations.

Esophagectomy-prevention of complications-tips and tricks for the preoperative, intraoperative and postoperative stage

Esophagectomy still remains the mainstay of treatment for localized esophageal cancer. Many progresses have been made in the technique of esophagectomy in the last decades but the overall morbidity for this operation remains formidable. Postoperative complication and mortality rate after esophagectomy are significant; anastomotic leak has an incidence of 11,4%. The occurrence of a complication is a significant negative prognostic factor for long term survival and is also linked to longer postoperative stay, a lower quality of life, increased hospital costs. Preventing the occurrence of postoperative morbidity and reducing associated postoperative mortality rate is a major goal for surgeons experienced in resective esophageal surgery. Many details of pre, intra and postoperative care for patients undergoing esophagectomy need to be shared among the professionals taking care of these patients (oncologists, dieticians, physiotherapists, surgeons, nurses, anesthesiologists, gastroenterologists) in order to improve the short and long term clinical results.

Reliability of bioreactance and pulse power analysis in measuring cardiac index during cytoreductive abdominal surgery with hyperthermic intraperitoneal chemotherapy (HIPEC)

PURPOSE

Various malignancies with peritoneal carcinomatosis are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). The hemodynamic instability resulting from fluid balance alterations during the procedure necessitates reliable hemodynamic monitoring. The aim of the study was to compare the accuracy, precision and trending ability of two less invasive hemodynamic monitors, bioreactance-based Starling SV and pulse power device LiDCOrapid with bolus thermodilution technique with pulmonary artery catheter in the setting of cytoreductive surgery with HIPEC.

METHODS

Thirty-one patients scheduled for cytoreductive surgery were recruited. Twenty-three of them proceeded to HIPEC and were included to the study. Altogether 439 and 430 intraoperative bolus thermodilution injections were compared to simultaneous cardiac index readings obtained with Starling SV and LiDCOrapid, respectively. Bland-Altman method, four-quadrant plots and error grids were used to assess the agreement of the devices.

RESULTS

Comparing Starling SV with bolus thermodilution, the bias was acceptable (0.13 l min^- 1 m^- 2, 95% CI 0.05 to 0.20), but the limits of agreement were wide (- 1.55 to 1.71 l min^- 1 m^- 2) and the percentage error was high (60.0%). Comparing LiDCOrapid with bolus thermodilution, the bias was acceptable (- 0.26 l min^- 1 m^- 2, 95% CI - 0.34 to - 0.18), but the limits of agreement were wide (- 1.99 to 1.39 l min^- 1 m^- 2) and the percentage error was high (57.1%). Trending ability was inadequate with both devices.

CONCLUSION

Starling SV and LiDCOrapid were not interchangeable with bolus thermodilution technique limiting their usefulness in the setting of cytoreductive surgery with HIPEC.

Functional Evaluation of Microcirculation in Response to Fluid Resuscitation in Hypovolemic Adult Post-cardiac Surgical Patients

Objectives:

Microcirculation is bound to be altered during cardiac surgery due to multiple factors, mainly the intense systemic inflammatory response syndrome which peaks in the first 24-h postoperatively. Decreased microvascular flow associated with increased postoperative morbidity has been reported. The literature suggests a potential independence of macrocirculation and microcirculation during fluid loading. The present study was conducted to assess thenar muscle tissue oxygen saturation (StO2) changes during vascular occlusion test (VOT) in response to hypovolemia and to assess the dynamic responses of the StO2 variables post-volume expansion (VE).

Material and Methods:

Thirty-five adult post-cardiac surgical patients, with stroke volume (SV) variation >12% were included in the study. Fifty-two fluid challenges were studied. Functional evaluation of microcirculation using VOT and near infrared spectroscopy (NIRS) variables along with monitoring of macrocirculatory indices was performed before and after VE. Statistical analysis was done using Student t-test.

Results:

Post-VE, 34 were responders with increase in SV ≥15% and 18 were non-responders (SV <15%). Rate of resaturation was significantly faster in responders compared to non-responders after VE (P = 0.0293 vs. P = 0.1480). However, macrocirculatory indices including cardiac output, SV, and delivery of oxygen showed significant improvement in both responders and non-responders.

Conclusion:

Preload dependence is associated with significant change in the StO2 recovery slope measured at the thenar eminence in volume responders. Functional evaluation of microcirculation using VOT and StO2 can be a useful complimentary tool along with the macrocirculatory indices for optimal fluid rescuscitaion in adult post-cardiac surgical patients.

Early recognition of risk of critical adverse events based on deep neural decision gradient boosting

Introduction

Perioperative critical events will affect the quality of medical services and threaten the safety of patients. Using scientific methods to evaluate the perioperative risk of critical illness is of great significance for improving the quality of medical services and ensuring the safety of patients.

Method

At present, the traditional scoring system is mainly used to predict the score of critical illness, which is mainly dependent on the judgment of doctors. The result is affected by doctors' knowledge and experience, and the accuracy is difficult to guarantee and has a serious lag. Besides, the statistical prediction method based on pure data type do not make use of the patient's diagnostic text information and cannot identify comprehensive risk factor. Therefore, this paper combines the text features extracted by deep neural network with the pure numerical type features extracted by XGBOOST to propose a deep neural decision gradient boosting model. Supervised learning was used to train the risk prediction model to analyze the occurrence of critical illness during the perioperative period for early warning.

Results

We evaluated the proposed methods based on the real data of critical illness patients in one hospital from 2014 to 2018. The results showed that the critical disease risk prediction model based on multiple modes had faster convergence rate and better performance than the risk prediction model based on text data and pure data type.

Discussion

Based on the machine learning method and multi-modal data of patients, this paper built a prediction model for critical adverse events in patients, so that the risk of critical events can be predicted for any patient directly based on the preoperative and intraoperative characteristic data. At present, this work only classifies and predicts the occurrence of critical illness during or after operation based on the preoperative examination data of patients, but does not discuss the specific time when the patient was critical illness, which is also the direction of our future work.

Goal-Directed Fluid Therapy and major postoperative complications in elective craniotomy. A retrospective analysis of a before-after multicentric study

BACKGROUND

Goal-Directed Fluid Therapy (GDFT) is recommended to decrease major postoperative complications. However, data are lacking in intra-cranial neurosurgery.

METHODS

We evaluated the efficacy of a GDFT protocol in a before/after multi-centre study in patients undergoing elective intra-cranial surgery for brain tumour. Data were collected during 6 months in each period (before/after). GDFT was performed in high-risk patients: ASA score III/IV and/or preoperative Glasgow Coma Score (GCS) < 15 and/or history of brain tumour surgery and/or tumour greater size ≥ 35 mm and/or mid-line shift ≥ 3 mm and/or significant haemorrhagic risk. Major postoperative complication was a composite endpoint: re-intubation after surgery, a new onset of GCS < 15 after surgery, focal motor deficit, agitation, seizures, intra-cranial haemorrhage, stroke, intra-cranial hypertension, hospital-acquired related pneumonia, surgical site infection, cardiac arrythmia, invasive mechanical ventilation ≥ 48 h and in-hospital mortality.

RESULTS

From July 2018 to January 2021, 344 patients were included in 3 centers: 171 in the before and 173 in the after (GDFT) period. Thirty-six (21.1%) patients displayed a major postoperative complication in the Before period, and 50 (28.9%) in the After period (p = 0.1). In the propensity score analysis, we matched 48 patients in each period: 9 (18.8%) patients in the After period and 14 (29.2%) patients in the Before period displayed a major perioperative complication (p = 0.2). Sixty-two (35.8%) patients received GDFT in the After period, with great heterogeneity among centers (p < 0.05).

CONCLUSIONS

In our before-after study, GDFT was not associated with a decrease in postoperative major complications in elective intra-cranial neurosurgery.