Intraoperative fluid management: Past and future, where is the evidence?

Incidence of postoperative pulmonary congestion as diagnosed by lung ultrasound in surgeries performed under general anaesthesia: A prospective, observational study

Background and Aims

Administering liberal fluid raises concerns about pulmonary congestion postoperatively. Bedside ultrasonography is a valuable tool for the early detection of pulmonary congestion. In this study, we have used it to ascertain the impact of the duration of surgery and intraoperative fluid volume on the causation of pulmonary congestion. Our objective was to determine the incidence of pulmonary congestion as diagnosed by lung ultrasound in patients undergoing general anaesthesia with varied fluid administration.

Methods

Seventy participants of American Society of Anesthesiologists physical status I and II, aged between 18 and 60 years, undergoing elective extrathoracic surgeries of over 3 h under general anaesthesia were included. Preoperative lung ultrasound was carried out in all patients, and a postoperative lung ultrasound was carried out at 1 h after extubation. The appearance of three or more "B"-lines was considered positive for lung congestion.

Results

Significant differences (P < 0.001) were found in the duration of surgery and the appearance of B-lines in the postoperative period. Participants who developed B lines received, on average, 150% more fluid (1148.16 ± 291.79 ml) than those who did not (591.29 ± 398.42 ml) (P = 0.0240). Net fluid balance was also significantly different in patients who developed B lines (P = 0.0014). None of the patients developed symptoms of lung congestion postoperatively.

Conclusion

Long duration of surgery under general anaesthesia (>3 h) with the administration of large volumes of intraoperative fluid and a large net fluid balance are associated with lung congestion as diagnosed by lung ultrasound.

Perioperative fluid management for lung transplantation is challenging

Lung transplantation is the definitive end-stage treatment for many lung diseases, and postoperative pulmonary oedema severely affects survival after lung transplantation. Optimizing perioperative fluid management can reduce the incidence of postoperative pulmonary oedema and improve the prognosis of lung transplant patients by removing the influence of patient, donor's lung and ECMO factors. Therefore, this article reviews seven aspects of lung transplant patients' pathophysiological characteristics, physiological characteristics of fluids, the influence of the donor lung on pulmonary oedema as well as current fluid rehydration concepts, advantages or disadvantages of intraoperative monitoring tools or types of fluids on postoperative pulmonary oedema, while showing the existing challenges in section 7. The aim is to show the specificity of perioperative fluid management in lung transplant patients and to provide new ideas for individualised fluid management in lung transplantation.

Effects of intra-operative fluid management under the guidance of stroke volume variability on short-term prognosis after thoracoscopic lobectomy

AIM

We aimed to explore the influence of intra-operative fluid management under the guidance of stroke volume variability (SVV) on the short-term prognosis after thoracoscopic lobectomy.

METHODS

A total of 171 eligible patients from April 2017 to April 2019 were selected. All patients received intra-operative fluid management under the guidance of SVV, and were divided into low-, middle- and high-level groups (n = 57) using a random-numbers table. The general data, respiratory function indices at different time points, haemodynamic indices at different time points, use of vasoactive drugs, short-term prognosis indices and incidence of complications were compared.

RESULTS

There were no significant differences in age, gender, operation time, one-lung ventilation time, amount of bleeding, arterial partial pressure of oxygen, arterial partial pressure of carbon dioxide, lung compliance and peak airway pressure at different time points, usage amount of anisodamine and incidence rate of complications among the three groups. In the low-level group, the fluid infusion amount and urine volume were significantly larger, the forced expiratory volume in one second (FEV1), percentage of FEV1 in the predicted value (FEV1%pred) and FEV1/forced vital capacity (FEV1/FVC) seven days after operation were higher, and the six-minute walk test (6MWT) distance was longer than those in the other two groups. The usage amount of dopamine, norepinephrine and esmolol was smaller, and the postoperative exhaust time was shorter than those in the other two groups. The low-level group had a smaller usage amount of isosorbide dinitrate injection and shorter length of postoperative hospital stay than the high-level group. Stroke volume had a significant difference at T2 and T3 in the low-level group, central venous pressure (CVP) and stroke volume had significant differences at T2 and T3 in the middle-level group, and heart rate (HR), mean arterial pressure and CVP were significantly different at T2 and T3 in the high-level group.

CONCLUSIONS

Fluid management under the guidance of low-level SVV (8% ≤ SVV ≤ 9%) was conducive to the maintenance of stable haemodynamics in patients during thoracoscopic lobectomy, thereby improving short-term prognosis.

Physiologic Effects of Prolonged Terminal Anesthesia in Sheep (Ovis gmelini aries)

The ruminant alimentary tract and its effects on blood homeostasis complicate prolonged terminal studies conducted under general anesthesia in sheep. We therefore studied 15 healthy female white alpine sheep that were undergoing prolonged anesthesia (> 30 h) for an unrelated terminal study. In the current study, all sheep developed a decreased hematocrit and hemoglobin concentration after induction of anesthesia, which fell further, along with a significant decrease in white blood cell count, over the course of anesthesia. Sheep also showed an initial hyponatremia, a persistent hypokalemia, hypocalcemia, and a progressive hyperchloremia. A significant drop in blood pH developed over time despite normal values of blood lactate and a marked decline in partial pressure of carbon dioxide over the course of the experiment. The latter consequently reduced the efficacy of mechanical ventilation, as reflected in a reduced oxygen partial pressure. A significant increase in lactate dehydrogenase and creatinine kinase was observed. Arterial blood pressure and heart rate significantly decreased over time, but remained within normotensive and normocardic limits. Central venous pressure rose significantly over the course of anesthesia. In conclusion, prolonged anesthesia in sheep is associated with a wide range of complex physi- ologic changes. An in-depth understanding of all metabolic compensatory mechanisms and their underlying cause during prolonged anesthesia is necessary for interpreting data from the primary study, with special considerations to account for ruminant-specific physiology.

The Effect of Goal-Directed Fluid Administration on Outcomes After Pancreatic Surgery

BACKGROUND

We evaluated the effect of an Enhanced Recovery After Surgery protocol on intraoperative fluid administration and postoperative outcomes in pancreatic surgery.

METHODS

Pancreatic cancer resections at our institution from 2012 to 2018 were grouped according to pre- or post-protocol initiation. Preoperative characteristics and postoperative outcomes were compared with Fisher's exact test and chi-square for categorical variables, and Mann-Whitney U test for continuous variables. Further analysis separated patients that had a Whipple from those who had distal pancreatectomy.

RESULTS

A total of 263 patients underwent pancreatic cancer resection during the study period (169 Whipples, 84 DPs, 92 pre-ERAS and 171 post-ERAS). Intraoperative fluid administration significantly decreased after protocol implementation (mean 6,277 ml vs. 3870 ml, p < 0.001). This held true when separating patients that had a Whipple procedure from those that had a DP (6,929 ml vs. 4,513 ml, p < 0.001, 5,060 ml vs. 2,833 cc, p = 0.002, respectively). Intensive care unit (ICU) admission (41.3% vs. 20.5%, p < 0.001) and length of stay (9.4 vs. 8.1 days, p < 0.01) were significantly reduced after ERAS implementation for all patients and in Whipple patients alone (47.5% vs. 23.6%, p = 0.002 and 10.7 vs. 6.6 days, p = 0.004). DP patients also had significantly decreased ICU admissions (41.3% vs. 20.5%, p = 0.045). All other postoperative outcomes were not significantly different.

CONCLUSION

For patients undergoing pancreatic cancer resection, goal-directed fluid management is associated with decreased intraoperative fluid administration, decreased ICU admission, and decreased length of stay without an increase in postoperative complications or readmission.

Preoperative Evaluation and Management of Patients With Select Chronic Gastrointestinal, Liver, and Renal Diseases

Patients with chronic gastrointestinal, hepatic, and renal disease are frequently encountered in clinical practice. This is due in part to the rising prevalence of risk factors associated with these conditions. These patients are increasingly being considered for surgical intervention and are at higher risk for multiple perioperative complications. Many are able to safely undergo surgery but require unique considerations to ensure optimal perioperative care. In this review, we highlight relevant perioperative physiology and outline our approach to the evaluation and management of patients with select chronic gastrointestinal, hepatic, and renal diseases. A comprehensive preoperative evaluation with a multidisciplinary approach is often beneficial, and specialist involvement should be considered. Intraoperative and postoperative plans should be individualized based on the unique medical and surgical characteristics of each patient.

Enhanced recovery after surgery for major orthopedic surgery: a narrative review

Background

With increasing interest in enhanced recovery after surgery (ERAS), the literature on ERAS in orthopedic surgery is also rapidly accumulating. This review article aims to (1) summarize the components of the ERAS protocol applied to orthopedic surgery, (2) evaluate the outcomes of ERAS in orthopedic surgery, and (3) suggest practical strategies to implement the ERAS protocol successfully.

Main body

Overall, 17 components constituting the highly recommended ERAS protocol in orthopedic surgery were identified. In the preadmission period, preadmission counseling and the optimization of medical conditions were identified. In the preoperative period, avoidance of prolonged fasting, multimodal analgesia, and prevention of postoperative nausea and vomiting were identified. During the intraoperative period, anesthetic protocols, prevention of hypothermia, and fluid management, urinary catheterization, antimicrobial prophylaxis, blood conservation, local infiltration analgesia and local nerve block, and surgical factors were identified. In the postoperative period, early oral nutrition, thromboembolism prophylaxis, early mobilization, and discharge planning were identified. ERAS in orthopedic surgery reduced postoperative complications, hospital stay, and cost, and improved the patient outcomes and satisfaction with accelerated recovery. For successful implementation of the ERAS protocol, various strategies including the standardization of care system, multidisciplinary communication and collaboration, ERAS education, and continuous audit system are necessary.

Conclusion

The ERAS pathway enhanced patient recovery with a shortened length of stay, reduced postoperative complications, and improved patient outcomes and satisfaction. However, despite the significant progress in ERAS implementation in recent years, it has mainly focused on major surgeries such as arthroplasty. Therefore, further efforts to apply, audit, and optimize ERAS in various orthopedic surgeries are necessary.

Barriers to Accurate Fluid Measurement in Perioperative Patients: A Mixed Methods Approach

BACKGROUND

Surgeons depend on fluid intake and output (I/O) measurements for assessment of resuscitation and fluid balance during the perioperative period. Frequently, these measurements are taken by Registered Nurses (RNs) and/or Patient Care Technicians (PCTs). There is variability in the accuracy and consistency of these measurements across nursing units. The goal of this study is to establish what barriers exist in obtaining accurate fluid measurements and potential solutions.

MATERIALS AND METHODS

A mixed-method, sequential study design was utilized. First, a survey was conducted at a tertiary care institution of 8 nonintensive care nursing units assessing the perceptions of RNs (n = 85) and PCTs (n = 38) regarding fluid intake and output measurements for surgical patients. Four focus groups were then conducted to expand upon the results of the survey. Fourteen participants (10 RNs and 4 PCTs) were interviewed, and transcripts were analyzed by three reviewers. Qualitative data were manually coded by reviewers using a hierarchical methodology.

RESULTS

Survey response rate was 40.6%. The strongest barriers in the survey were patient load and staff time limitations. About half (49%) of the respondents acknowledged that fluid measurements were inaccurate half of the time. PCTs spend more time collecting and charting I/Os and have higher patient loads (P < 0.001) than RNs. PCTs noted more difficulty with complex patients (P = 0.017) and devices for outputs (P = 0.004). PCT's (94%) handwrite data prior to electronic entry. One-third of nurses reported direct electronic entry (P < 0.001). Overall, 71% would prefer to chart in patient's rooms. Most (80%) of respondents received <5 h of fluids-related training at the time they were hired. Cronbach's alpha for three focus group reviewers was 0.84 (95% CI 0.693-0.923). Themes included understaffing, lack of training, a high percentage of traveling nurses, and poor communication regarding new orders. Recommended solutions to improve I/Os included in-room kiosks for electronic entry and relief of staffing burdens.

CONCLUSIONS

Fluid I/O measurement accuracy and efficiency may be improved by increased staffing, educational programs, and computer access, streamlining of order sets, simplicity of EMR data entry, and a standardized process for measuring, recording, and charting I/Os.

Restrictive versus Liberal Fluid Therapy for Post-Cesarean Acute Kidney Injury in Severe Preeclampsia: a Pilot Randomized Clinical Trial

OBJECTIVES

The aim of this study was to determine whether a restrictive compared to a liberal fluid therapy will increase postoperative acute kidney injury (AKI) in patients with severe preeclampsia.

METHODS

A total of 46 patients (mean age, 32 years; standard deviation, 6.8 years) with severe preeclampsia were randomized to liberal (1500 ml of lactated Ringer's, n=23) or restrictive (250 ml of lactated Ringer's, n=23) intravenous fluid regimen during cesarean section. The primary outcome was the development of a postoperative renal dysfunction defined by AKI Network stage ≥1. Serum cystatin C and neutrophil gelatinase-associated lipocalin (NGAL) were evaluated at postoperative days 1 and 2. ClinicalTrials.gov: NCT02214186.

RESULTS

The rate of postoperative AKI was 43.5% in the liberal fluid group and 43.5% in the restrictive fluid group (p=1.0). Intraoperative urine output was higher in the liberal (116 ml/h, IQR 69-191) than in the restrictive fluid group (80 ml/h, IQR 37-110, p<0.05). In both groups, serum cystatin C did not change from postoperative day 1 compared to the preoperative period and significantly decreased on postoperative day 2 compared to postoperative day 1 (p<0.05). In the restrictive fluid group, NGAL levels increased on postoperative day 1 compared to the preoperative period (p<0.05) and decreased on postoperative day 2 compared to postoperative day 1 (p<0.05).

CONCLUSION

Among patients with severe preeclampsia, a restrictive fluid regimen during cesarean section was not associated with increased postoperative AKI.