Fatal postoperative pulmonary edema: pathogenesis and literature review

Risk factors for venous thrombosis after esophagectomy

BACKGROUND

Venous thrombosis (VT) after esophagectomy for esophageal cancer is an important complication, potentially leading to pulmonary embolism. However, there are few available information about the risk for the postsurgical VT.

METHODS

This study included 271 patients who underwent esophagectomy for esophageal cancer between 2006 and 2019. Contrast-enhanced computed tomography (CT) was performed for all patients on the seventh postoperative day to survey complications, including VT.

RESULTS

VT was radiologically visualized in 48 patients (17.7%), 8 of whom (16.7%) had pulmonary embolism. The thrombus disappeared in 42 patients, the thrombus size was unchanged in 5 patients, and 1 patient died. Multivariate analysis was performed on factors clinically considered to have a significant influence on thrombus formation. The analysis showed that CVC insertion via the femoral vein (odds ratio, 7.67; 95% CI, 2.64-22.27; P < 0.001), retrosternal reconstruction route (odds ratio, 3.94; 95% CI, 1.90-8.17; P < 0.001) and intraoperative fluid balance < 5 ml/kg/hr (odds ratio, 0.38; 95% CI, 0.17-0.85; P = 0.019) were independently related to VT.

CONCLUSIONS

Intraoperative fluid balance < 5 ml/kg/hr, along with CVC insertion via the femoral vein and retrosternal reconstruction may be potential risk factors for VT after esophagectomy.

The clinical significance of hypoalbuminaemia

Albumin is a relatively small molecule with a radius of 7.5 nm and a molecular weight of 65 kDa. It is the most abundant protein in plasma, accounting for 60-75% of its oncotic pressure. Its concentration in plasma is merely one static measurement reflecting a dynamic and complex system of albumin physiology, and is the net result of several different processes, one or more of which may become deranged by disease or its treatment. It is also unsurprising that hypoalbuminaemia has proved to be an indicator of morbidity and mortality risk since the underlying conditions which cause it, including protein energy malnutrition, crystalloid overload, inflammation, and liver dysfunction are themselves risk factors. In some cases, its underlying cause may require treatment but mostly it is just a parameter to be monitored and used as one measure of clinical progress or deterioration. While malnutrition, associated with a low protein intake, may be a contributory cause of hypoalbuminaemia, in the absence of inflammation and/or dilution with crystalloid its development in response to malnutrition alone is slow compared with the rapid change caused by inflammatory redistribution or dilution with crystalloids. Other significant causes include liver dysfunction and serous losses. These causal factors may occur singly or in combination in any particular case. Treatment is that of the underlying causes and associated conditions such as a low plasma volume, not of hypoalbuminaemia per se.

Lipoplasty in the Overweight Patient

The practice of large volume liposuction, when executed by board-certified plastic surgeons using a variety of energy-assisted liposuction devices, has been substantiated as a secure procedure, yielding enhanced aesthetic results and minimal complications. Techniques including the superwet technique and ultrasonic-assisted liposuction are utilized to diminish blood loss, while also maintaining a keen awareness of the maximum volume of infiltration fluid permissible for safe infusion. Adherence to evidence-based protocols is of paramount importance to reduce the risk of postoperative complications. These protocols encompass hypothermia prevention, deep vein thrombosis (DVT) prophylaxis, and perioperative antibiotic prophylaxis. To ensure the highest quality of care, it is recommended that large volume liposuction procedures be performed in accredited hospitals or certified ambulatory surgery centers. Postoperative procedures should include overnight admission of patients to facilitate proper hemodynamic monitoring. While the employment of multiple devices such as VASERLipo and Renuvion has been noted to augment skin and soft tissue contraction, it is worth noting that there may be a heightened risk of seroma formation (at 2.27%) and subcutaneous emphysema (at 1.47%). Consequently, prudent use of these advanced medical devices is essential to avoid any potential adverse events.

Isotonic saline causes greater volume overload than electrolyte-free irrigating fluids

OBJECTIVES

Systemic absorption of the irrigating fluid used to flush the operating site is a potentially serious complication in several types of endoscopic operations. To increase safety, many surgeons have changed from a monopolar to a bipolar resection technique because 0.9% saline can then be used instead of electrolyte-free fluid for irrigation. The present study examines whether the tendency for excessive plasma volume expansion is greater with saline than with electrolyte-free fluid.

METHODS

Pooled data were analyzed from four studies in which a mean of 1.25 L of either 0.9% saline or an electrolyte-free irrigating fluid containing glycine, mannitol, and sorbitol was given by intravenous infusion on 80 occasions to male volunteers and patients scheduled for transurethral prostatic surgery. The distribution of the infused fluid was analyzed with a population volume kinetic model based on frequently measured hemodilution and the urinary excretion.

RESULTS

Electrolyte-free fluid distributed almost twice as fast and was excreted four times faster than 0.9% saline. The distribution half-life was 6.5 and 10.6 min for the electrolyte-free fluid and saline, respectively, and the elimination half-lives (by urinary excretion) from the plasma volume were 21 and 87 min. Simulation showed that the plasma volume expansion was twice as great from 0.9% saline than from electrolyte-free fluid.

CONCLUSIONS

Isotonic (0.9%) saline expands the plasma volume by twice as much as occurs with electrolyte-free irrigating fluids. This difference might explain why signs of cardiovascular overload are the most commonly observed adverse effects when saline is absorbed during endoscopic surgery.

Role of Crystalloids in the Perioperative Setting: From Basics to Clinical Applications and Enhanced Recovery Protocols

Perioperative fluid management, a critical aspect of major surgeries, is characterized by pronounced stress responses, altered capillary permeability, and significant fluid shifts. Recognized as a cornerstone of enhanced recovery protocols, effective perioperative fluid management is crucial for optimizing patient recovery and preventing postoperative complications, especially in high-risk patients. The scientific literature has extensively investigated various fluid infusion regimens, but recent publications indicate that not only the volume but also the type of fluid infused significantly influences surgical outcomes. Adequate fluid therapy prescription requires a thorough understanding of the physiological and biochemical principles that govern the body's internal environment and the potential perioperative alterations that may arise. Recently published clinical trials have questioned the safety of synthetic colloids, widely used in the surgical field. A new clinical scenario has arisen in which crystalloids could play a pivotal role in perioperative fluid therapy. This review aims to offer evidence-based clinical principles for prescribing fluid therapy tailored to the patient's physiology during the perioperative period. The approach combines these principles with current recommendations for enhanced recovery programs for surgical patients, grounded in physiological and biochemical principles.

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.

Intravenous-Therapy-Associated Circulatory Overload: A Retrospective Study of Forensic Cases

Background and Objective: Intravenous therapy is widely used in clinics to deliver medications and fluids to patients, and overuse may cause intravenous-infusion-associated circulatory overload (IACO) and death. However, forensic data on deaths from the overuse of intravenous therapy are limited. We performed a retrospective study to identify whether causes of death in forensic practice were associated with IACO. Methods: A total of 572 medical-related cases with a history of intravenous infusion who suffered from injuries or illnesses and died after treatment in hospitals were recruited from two centers of forensic medicine between 2002 and 2018. Results: The results demonstrated that 6.47% of cases (37/572) were exposed to an infusion overdose that resulted in deaths related to IACO, and 43.24% of cases (16/37) had a net fluid retention ranging from 3.0 L/d to 13.8 L/d. The highest case was administered 1.4 L blood products and 13.6 L fluids within 25 h. We observed significant decreases in red blood cells, hematocrit, hemoglobin, and platelets from the time of “on admission” to “before death”, except for white blood cells. Autopsy findings of 16 cases revealed some organ or tissue pathological alterations related to IACO, including pale-yellow liquid overflow under the abdominal epidermis, much transudate in body cavities, and lung edema with a high tissue density and no obvious slurry deposition in the alveolar lumen. Another 21 cases died after a rapid infusion rate ranging from 111 to 293 drops/min, which resulted from viral myocarditis on autopsy. Conclusions: Our data on excessive or irrational use of intravenous therapy indicate a severe circulatory overload, which may eventually result in lethal outcomes. Therefore, the use of improper intravenous therapy should be reduced to ameliorate adverse health consequences during clinical treatment.

Influence of Alveolar Fluid on Aquaporins and Na+/K+-ATPase and Its Possible Theoretical or Clinical Significance

OBJECTIVE

Pulmonary edema is the most common pathophysiological change in pulmonary disease. Aquaporins (AQPs) and Na⁺/K⁺-ATPase play pivotal roles in alveolar fluid clearance. This study aimed to explore the influence of increased alveolar fluid on the absorption of lung fluid.

STUDY DESIGN

Eighty New Zealand rabbits were randomly divided into eight groups (n = 10 in each group), and models of different alveolar fluid contents were established by the infusion of different volumes of normal saline (NS) via the endotracheal tube. Five animals in each group were sacrificed immediately after infusion to determine the wet/dry ratio, while the remaining animals in each group were killed 4 hours later to determine the wet/dry ratio at 4 hours. Additionally, lung specimens were collected from each group, and quantitative real-time PCR (qRT-PCR), western blot, and immunohistochemical (IHC) analyses of AQPs and Na⁺/K⁺-ATPase were performed.

RESULTS

The qRT-PCR analysis and western blot studies showed markedly decreased mRNA and protein levels of AQP1 and Na⁺/K⁺-ATPase when the alveolar fluid volume was ≥6 mL/kg, and the mRNA level of AQP5 was significantly reduced when the alveolar fluid volume was ≥4 mL/kg. In addition, IHC analysis showed the same results. At 4 hours, the lung wet/dry ratio was significantly increased when the alveolar fluid volume was ≥6 mL/kg; however, compared with 0 hours after NS infusion, there was still a significant absorption of alveolar fluid for a period of 4 hours.

CONCLUSION

The results of this study suggest that increased alveolar fluid may induce the downregulation of the mRNA and protein expression of AQPs and Na⁺/K⁺-ATPase, which appear to affect alveolar fluid clearance in rabbit lungs. Early intervention is required to avoid excessive alveolar fluid accumulation.

KEY POINTS

· The expression levels of AQPs and Na+/K+--ATPase were significantly decreased as alveolar fluid increased.. · At 4 hours, wet/dry ratio was significantly increased when infusion volume was ≥ 6 mL/kg.. · Early intervention is required to avoid excessive alveolar fluid accumulation..

The physiologic responses to a fluid bolus administration in old and young healthy adults

BACKGROUND

Organ function is known to decline with age. Optimizing cardiac, pulmonary and renal function in older adults has led to significant improvements in perioperative care. However, when substantial blood loss and fluid shifts occur, perioperative outcomes still remains poor, especially in older adults. We suspect that this could be due to age-related changes in endothelial function-an organ controlling the transport of fluid and solutes. The capillary filtration coefficient (CFC) is an important determinant of fluid transport. The CFC can be measured in vivo, which provides a tool to estimate endothelial barrier function. We have previously shown that the CFC increases when giving a fluid bolus resulting in increased vascular and extravascular volume expansion, in young adults. This study aimed to compare the physiologic determinants of fluid distribution in young versus older adults so that clinicians can best optimize perioperative fluid therapy.

METHODS

Ten healthy young volunteers (ages 21-35) and nine healthy older volunteers (ages 60-75) received a 10 mL/kg fluid bolus over the course of twenty minutes. Hemodynamics, systolic and diastolic heart function, fluid volumetrics and microcirculatory determinants were measured before, during, and after the fluid bolus.

RESULTS

Diastolic function was reduced in older versus younger adults before and after fluid bolus (P < 0.01). Basal CFC and plasma oncotic pressure were lower in the older versus younger adults. Further, CFC did not increase in older adults following the fluid bolus, whereas it did in younger adults (p < 0.05). Cumulative urinary output, while lower in older adults, was not significantly different (p = 0.059). Mean arterial pressure and systemic vascular resistance were elevated in the older versus younger adults (p < 0.05).

CONCLUSION

Older adults show a less reactive CFC to a fluid bolus, which could reduce blood to tissue transport of fluid. Diastolic dysfunction likely contributes to fluid maldistribution in older adults.

Utility of Lung Ultrasound in the Estimation of Extravascular Lung Water in a Pediatric Population-A Prospective Observational Study

OBJECTIVE

Lung ultrasound (LUS) is a promising bedside modality for the estimation of extravascular lung water index (EVLWI), but has not been validated against objective measures in children. This study aimed to investigate the correlation of LUS B-line scoring with EVLWI, thresholds indicating elevated EVLWI, and its outcome following pediatric cardiac surgery.

DESIGN

Prospective observational study.

SETTING

Cardiothoracic surgical intensive care unit in a tertiary care teaching hospital.

PARTICIPANTS

Children younger than 12 years undergoing elective complete surgical correction of cyanotic or acyanotic congenital heart disease (Aristotle score ≤9), excluding neonates, those weighing <3.5 kg, and those with thoracic deformities, pulmonary pathology, and hemodynamic instability.

INTERVENTIONS

Extravascular lung water index measurement by transpulmonary thermodilution, along with concurrent LUS B-line and Chest-X ray (CXR) scoring.

MEASUREMENTS AND MAIN RESULTS

LUS B-line score had a moderate correlation with EVLWI (Pearson's correlation coefficient 0.57; 95% CI 0.44-0.69). LUS B-line scores showed acceptable discrimination only for higher thresholds of EVLWI (sensitivity 82% and 79%, respectively, for EVLWI >20 mL/kg v sensitivity and specificity 57% and 80% for EVLWI >10 mL/kg). Age, body surface area, vasoactive-inotropic score (VIS), chest X-ray score, and EVLWI but not LUS B-line score were significant predictors for duration of mechanical ventilation in this cohort.

CONCLUSIONS

LUS B-line scoring has limited utility in semiquantitative estimation of EVLWI at lower thresholds of EVLWI in pediatric cardiac surgical patients. It may have better discrimination and acceptable sensitivity and specificity at higher thresholds of EVLWI. Contrasting with multiple reports of clinical utility, these results call for wider evaluation of LUS and its clinical modifiers like age, pathology, and pretest probability in estimation of EVLWI.

Effect of Intra- and Post-Operative Fluid and Blood Volume on Postoperative Pulmonary Edema in Patients with Intraoperative Massive Bleeding

In patients with intraoperative massive bleeding, the effects of fluid and blood volume on postoperative pulmonary edema are uncertain. Patients with intraoperative massive bleeding who had undergone a non-cardiac surgery in five hospitals were enrolled in this study. We evaluated the association of postoperative pulmonary edema risk and intra- and post-operatively administered fluid and blood volumes in patients with intraoperative massive bleeding. In total, 2090 patients were included in the postoperative pulmonary edema analysis, and 300 patients developed pulmonary edema within 72 h of the surgery. The postoperative pulmonary edema with hypoxemia analysis included 1660 patients, and the condition occurred in 161 patients. An increase in the amount of red blood cells transfused per hour after surgery increased the risk of pulmonary edema (hazard ratio: 1.03; 95% confidence interval: 1.01–1.05; p = 0.013) and the risk of pulmonary edema with hypoxemia (hazard ratio: 1.04; 95% confidence interval: 1.01–1.07; p = 0.024). An increase in the red blood cells transfused per hour after surgery increased the risk of developing pulmonary edema. This increase can be considered as a risk factor for pulmonary edema.

Fluid escapes to the "third space" during anesthesia, a commentary

BACKGROUND

The "third fluid space" is a concept that has caused much confusion for more than half a century, dividing anesthesiologists into believers and non-believers.

AIM

To challenge the existence of the "third fluid space" based on analysis of crystalloid fluid kinetics.

METHODS

Data on hemodilution patterns from 157 infusion experiments performed in volunteers and from 85 patients undergoing surgery under general anesthesia were studied by population volume kinetic analysis. Elimination of infused crystalloid fluid from the kinetic model could occur either as urine or "third space" accumulation. The latter fluid volume remained in the body, but without equilibrating with the plasma within the 3-4 h of the experiment.

RESULTS

The rate constant for "third space" loss of fluid accounted for 20% of the elimination in conscious volunteers and for 75% during general anesthesia and surgery. The two elimination constants showed a reciprocal relationship, resulting in that "third-space" losses increase when urinary excretion is restricted. The effect on the plasma volume was smaller than indicated by these figures because fluid distributed to the extravascular space continuously redistributed to the plasma. Worked-out examples show that one-third of an infused crystalloid volume has been confined to the "third space" after 3 h of surgery. When equilibration with the plasma eventually occurs, which is necessary for excretion of the fluid, is not known.

CONCLUSION

During anesthesia and surgery one third of the infused crystalloid fluid is at least temporarily unavailable for excretion, which probably contributes to postoperative weight increase and edema.

Perioperative fluid balance and major postoperative complications in surgery for advanced epithelial ovarian cancer

OBJECTIVE

Appropriate fluid balance in the perioperative period is important as both hypo- and hypervolemia are associated with increased risk of complications. Women undergoing cytoreductive surgery (CRS) for advanced epithelial ovarian cancer (EOC) may have major fluid shifts. The optimal perioperative fluid balance in these women is yet to be determined. Our objective was to investigate the association between perioperative fluid balance and major postoperative complications.

METHODS

Women with advanced stage EOC who underwent surgery at Karolinska University Hospital, Stockholm, Sweden were identified from the institutional database. Women subjected to surgery with curative intent were included in the analysis. Additional data were retrieved from medical records. The association between perioperative fluid balance and major postoperative complications was investigated by multivariable regression and adjusted for predefined confounders.

RESULTS

Of the 270 women identified in the institutional database during 2014-2017, 184 women were included in the analyses. Of these women, 22% (n = 40) experienced a major postoperative complication. The fully adjusted odds of major postoperative complications increased when perioperative fluid balance exceeded >3000 mL, (Odds Ratio (OR) 4.85, 95% Confidence Interval (CI) 1.23-19.2, p = 0.02) and > 5000 mL (OR 33.7, 95% CI 4.13-275, p < 0.01). There was no association between negative fluid balance and major postoperative complications (OR 3.33, 95% CI 0.25-44.1, p = 0.36).

CONCLUSIONS

Fluid balance >3000 mL perioperatively during surgery for advanced EOC increased the odds of major postoperative complications. Management of perioperative fluid balance in advanced EOC surgery remains a challenge.

Phases of fluid management and the roles of human albumin solution in perioperative and critically ill patients

OBJECTIVE

Positive fluid balance is common among critically ill patients and leads to worse outcomes, particularly in sepsis, acute respiratory distress syndrome, and acute kidney injury. Restrictive fluid infusion and active removal of accumulated fluid are being studied as approaches to prevent and treat fluid overload. Use of human albumin solutions has been investigated in different phases of restrictive fluid resuscitation, and this narrative literature review was undertaken to evaluate hypoalbuminemia and the roles of human serum albumin with respect to hypovolemia and its management.

METHODS

PubMed/EMBASE search terms were: "resuscitation," "fluids," "fluid therapy," "fluid balance," "plasma volume," "colloids," "crystalloids," "albumin," "hypoalbuminemia," "starch," "saline," "balanced salt solution," "gelatin," "goal-directed therapy" (English-language, pre-January 2020). Additional papers were identified by manual searching of reference lists.

RESULTS

Restrictive fluid administration, plus early vasopressor use, may reduce fluid balance, but in some cases fluid overload cannot be entirely avoided. Deresuscitation, with fluid actively removed through diuretics or ultrafiltration, reduces duration of mechanical ventilation and intensive care unit stay. Combining hyperoncotic human albumin solution with diuretics increases hemodynamic stability and diuresis. Hyperoncotic albumin corrects hypoalbuminemia and raises colloid osmotic pressure, limiting edema formation and potentially improving endothelial function. Serum levels of albumin relative to C-reactive protein and lactate may predict which patients will benefit most from albumin therapy.

CONCLUSIONS

Hyperoncotic human albumin solution facilitates restrictive fluid therapy and the effectiveness of deresuscitative measures. Current evidence is mostly from observational studies, and more randomized trials are needed to better establish a personalized approach to fluid management.

Fluid management knowledge in hospital physicians: 'Greenshoots' of improvement but still a cause for concern

Fluid management is an essential competency for hospital doctors, but previous studies suggest junior clinicians lack the necessary 'knowledge' and 'prescription skills' to complete this task, resulting in preventable morbidity and mortality. In this study, preregistration (n=146), core (n=66) and specialty (n=133) medical trainees and general medical consultants (n=11) completed a structured questionnaire exploring fluid management training, confidence, serious adverse event experience and a 20-item fluid management 'knowledge' test. Results were compared with those of intensive care consultants (n=20). Most clinicians reported limited training and extensive 'unreported' serious adverse events experience. Knowledge about fluid and electrolyte requirements, fluid composition and chloride toxicity had improved compared to historical reports but overall test scores (median (interquartile range (IQR)): with a maximum score of 20) were low. Foundation year trainees scored 7 (IQR 5-8), core medical trainees scored 9 (IQR 6-10), specialist registrars scored 8 (IQR 6-10) and general medical consultants scored 8 (IQR 6-12) compared with the intensive care consultant score of 16 (IQR 14-16). Although weakly correlated, fluid management 'confidence' appeared higher than 'knowledge' tests would justify. These results suggest that physicians' fluid management knowledge is inadequate, including that of senior colleagues, compounded by poor training and failure to learn from serious adverse events.

Role of TFA-1 adhesive forehead sensors in predicting fluid responsiveness in anaesthetised children: A prospective cohort study

BACKGROUND

The TFA-1 adhesive forehead sensor is a newly developed pulse oximeter for the measurement of the plethysmographic variability index (PVI) at the forehead, and for the rapid detection of changes in oxygen saturation during low perfusion.

OBJECTIVES

We evaluated the ability of the TFA-1 sensor to predict fluid responsiveness in children under general anaesthesia.

DESIGN

Prospective cohort study.

SETTING

Single tertiary care children's hospital.

PATIENTS

Thirty-seven children aged 1 to 5 years under general anaesthesia and requiring invasive arterial pressure monitoring.

MAIN OUTCOME MEASURES

The baseline PVI of TFA-1 and finger sensors, respiratory variation of aorta blood flow peak velocity (ΔVpeak) and stroke volume index (SVI) obtained using transthoracic echocardiography were assessed. After fluid loading of 10 ml kg crystalloids over 10 min, SVI was reassessed. Responders were defined as those with an increase in SVI greater than 15% from the baseline. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive ability of the PVI of TFA-1 and finger sensors and ΔVpeak for fluid responsiveness.

RESULTS

Seventeen (56.6%) patients responded to volume expansion. Before fluid loading, the PVI of TFA-1 and finger sensors and ΔVpeak (mean ± SD) of the responders were 11.2 ± 4.4, 11.4 ± 5.1 and 14.8 ± 3.9%, respectively, and those of the nonresponders were 7.4 ± 3.9, 8.1 ± 3.6 and 11.0 ± 3.3%, respectively. ROC curve analysis indicated that the PVI of TFA-1 and finger sensors and ΔVpeak could predict fluid responsiveness. The areas under the curve were 0.8 [P = 0.00; 95% confidence interval (CI) 0.60 to 0.91], 0.7 (P = 0.02; 95% CI 0.53 to 0.87) and 0.8 (P = 0.00; 95% CI 0.59 to 0.91), respectively. The cut-off values for the PVI of TFA-1 and finger sensors and ΔVpeak were 6.0, 9.0 and 10.6%, respectively.

CONCLUSION

The PVI of TFA-1 forehead sensor is a good alternative, but is not superior to the finger sensor and ΔVpeak in evaluating fluid responsiveness in mechanically ventilated children under general anaesthesia.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov, NCT03132480.

Intraoperative Management of a Patient With Impaired Cardiac Function Undergoing Simultaneous ABO-Compatible Liver and ABO-Incompatible Kidney Transplant From 2 Living Donors: A Case Report

BACKGROUND

Combined liver and kidney transplant is a very complex surgery. To date, there has been no report on the intraoperative management of patients with impaired cardiac function undergoing simultaneous ABO-compatible liver and ABO-incompatible kidney transplant from 2 living donors.

CASE REPORT

A 60-year-old man underwent simultaneous ABO-compatible liver and ABO-incompatible kidney transplant from 2 living donors because of IgA nephropathy and alcoholic liver cirrhosis. The preoperative cardiac findings revealed continuous aggravation, shown by large left atrial enlargement, severe left ventricular hypertrophy, a very prolonged QT interval, and a calcified left anterior descending coronary artery. Severe hypotension with very weak pulsation and severe bradycardia developed, with an irregular junctional rhythm noted immediately after the liver graft was reperfused. Although epinephrine was administered as a rescue drug, hemodynamics did not improve, and central venous pressure and mean pulmonary arterial pressure increased to potentially fatal levels. Emergency phlebotomy via the central line was performed. Thereafter, hypotension and bradycardia recovered gradually as the central venous pressure and mean pulmonary arterial pressure decreased. The irregular junctional rhythm returned to a sinus rhythm, but the QTc interval was slightly more prolonged. Because of poor cardiac capacity, the volume and rate of fluid infusion were increased aggressively to maintain appropriate kidney graft perfusion after confirming vigorous urine production of the graft.

CONCLUSIONS

A heart with impaired function due to both end-stage liver and kidney diseases may be less able to withstand surgical stress. Further study on cardiac dysfunction will be helpful for the management of patients undergoing complex transplant surgery.

Impact of postoperative intravenous fluid administration on complications following elective hepato-pancreato-biliary surgery

BACKGROUND

The impact of perioperative intravenous fluid administration on surgical outcomes has been documented in literature, but not specifically studied in the context of hepato-pancreato-biliary (HPB) surgery. This study aimed to investigate the impact of postoperative intravenous fluid administration on intensive care unit (ICU), in this subgroup of patients.

METHODS

A single-center retrospective cohort of 241 HPB patients was assessed, focusing on intravenous fluid administration in ICU, during the first 24 h. Intravenous fluid variables were compared to hospital stay and postoperative complications. Data were assessed using Spearman's correlation test for bivariate correlations and logistic regression for multivariate analysis.

RESULTS

The median volume of intravenous fluid administered in the first 24 h postoperatively was 4380 mL, of which 2200 mL was crystalloid, 1500 mL colloid and 680 mL "other" fluid. Patients with one or more complications had a higher median total intravenous fluid input (4790 vs. 4300 mL), higher colloid volume (2000 vs. 1500 mL), lower urine output (1595 vs. 1900 mL) and greater overall fluid balance (+3040 vs.+2553 mL) than those without complications. There were correlations between total intravenous fluid volume administered (r = 0.278, P < 0.001), intravenous colloid input (r = 0.278, P < 0.001), urine output (r = -0.295, P < 0.001), positive fluid balance (r = 0.344, P < 0.001) and length of hospital stay. Logistic regression model was constructed to predict the occurrence of one or more complications; total intravenous fluid volume and overall fluid balance were both independent significant predictors (OR = 2.463, P = 0.007; OR = 1.001, P = 0.011; respectively).

CONCLUSIONS

Administration of high volumes of intravenous fluids in the first 24 hours post-HPB surgery, along with higher positive fluid balance is associated with a higher rate of complications and longer hospital stay. Moreover, lower urine output is associated with longer hospital stay. Whether these are the cause of complications or the result of them remains unclear.

Comparison of conventional fluid management with PVI-based goal-directed fluid management in elective colorectal surgery

Intraoperative fluid management is quite important in terms of postoperative organ perfusion and complications. Different fluid management protocols are in use for this purpose. Our primary goal was to compare the effects of conventional fluid management (CFM) with the Pleth Variability Index (PVI) guided goal-directed fluid management (GDFM) protocols on the amount of crystalloids administered, blood lactate, and serum creatinine levels during the intraoperative period. The length of hospital stay was our secondary goal. Seventy ASA I–II elective colorectal surgery patients were randomly assigned to CFM or GDFM for fluid management. The hemodynamic data and the data obtained from ABG were recorded at the end of induction and during the follow-up period at 1 h intervals. In the preoperative period and at 24 h postoperatively, blood samples were taken for the measurement of hemoglobin, Na, K, Cl, serum creatinine, albumin and blood lactate. In the first 24 h after surgery, oliguria and the time of first bowel movement were recorded. Length of hospital stay was also recorded. Intraoperative crystalloid administration and urine output were statistically significantly higher in CFM group (p < 0.001, p: 0.018). The end-surgery fluid balance was significantly lower in Group GDFM. Preoperative and postoperative Na, K, Cl, serum albumin, serum creatinine, lactate and hemoglobin values were similar between the groups. The time to passage of stool was significantly short in Group-GDFM compared to Group-CFM (p = 0.016). The length of hospital stay was found to be similar in both group. PVI-guided GDFM might be an alternative to CFM in ASA I–II patients undergoing elective colorectal surgery. However, further studies need to be carried out to search the efficiency and safety of PVI.

Restrictive versus Liberal Fluid Therapy for Major Abdominal Surgery

BACKGROUND

Guidelines to promote the early recovery of patients undergoing major surgery recommend a restrictive intravenous-fluid strategy for abdominal surgery. However, the supporting evidence is limited, and there is concern about impaired organ perfusion.

METHODS

In a pragmatic, international trial, we randomly assigned 3000 patients who had an increased risk of complications while undergoing major abdominal surgery to receive a restrictive or liberal intravenous-fluid regimen during and up to 24 hours after surgery. The primary outcome was disability-free survival at 1 year. Key secondary outcomes were acute kidney injury at 30 days, renal-replacement therapy at 90 days, and a composite of septic complications, surgical-site infection, or death.

RESULTS

During and up to 24 hours after surgery, 1490 patients in the restrictive fluid group had a median intravenous-fluid intake of 3.7 liters (interquartile range, 2.9 to 4.9), as compared with 6.1 liters (interquartile range, 5.0 to 7.4) in 1493 patients in the liberal fluid group (P<0.001). The rate of disability-free survival at 1 year was 81.9% in the restrictive fluid group and 82.3% in the liberal fluid group (hazard ratio for death or disability, 1.05; 95% confidence interval, 0.88 to 1.24; P=0.61). The rate of acute kidney injury was 8.6% in the restrictive fluid group and 5.0% in the liberal fluid group (P<0.001). The rate of septic complications or death was 21.8% in the restrictive fluid group and 19.8% in the liberal fluid group (P=0.19); rates of surgical-site infection (16.5% vs. 13.6%, P=0.02) and renal-replacement therapy (0.9% vs. 0.3%, P=0.048) were higher in the restrictive fluid group, but the between-group difference was not significant after adjustment for multiple testing.

CONCLUSIONS

Among patients at increased risk for complications during major abdominal surgery, a restrictive fluid regimen was not associated with a higher rate of disability-free survival than a liberal fluid regimen and was associated with a higher rate of acute kidney injury. (Funded by the Australian National Health and Medical Research Council and others; RELIEF ClinicalTrials.gov number, NCT01424150 .).

An Online Module to Understand Body Fluid Status in Clinical Cases

INTRODUCTION

A thorough understanding of body fluid alterations is essential for the success of both practicing dentists and physicians. However, the time constraints of professional school curricula often limit the time available in physiology courses to address this material.

METHODS

The primary goal of this resource was to improve student comprehension of body fluid status by using three online videos that explain volume-osmolality diagrams. An additional goal was to improve students' ability to apply their physiological knowledge by showcasing real-life clinical situations in medicine and dentistry. The videos were created using custom-designed PowerPoint animations, video recordings, and Camtasia video-editing software.

RESULTS

On assessment of exam performance, students performed similarly in sections of the course that were taught using the online modules versus face-to-face lectures. Student performance was extremely high on the body fluid assessment-questions, with an average of 95%. This high level of student performance was notable, particularly given the complexity of the questions.

DISCUSSION

These results indicate that this online volume-osmolality module enabled students to improve their comprehension of body fluid concepts in physiology. Furthermore, the data indicates the feasibility of replacing lectures with online modules, freeing valuable class time for active learning or more advanced physiological concepts.

Crystalloid fluid choice in the critically ill : Current knowledge and critical appraisal

Intravenous infusion of crystalloid solutions is one of the most frequently administered medications worldwide. Available crystalloid infusion solutions have a variety of compositions and have a major impact on body systems; however, administration of crystalloid fluids currently follows a "one fluid for all" approach than a patient-centered fluid prescription. Normal saline is associated with hyperchloremic metabolic acidosis, increased rates of acute kidney injury, increased hemodynamic instability and potentially mortality. Regarding balanced infusates, evidence remains less clear since most studies compared normal saline to buffered infusion solutes.; however, buffered solutes are not homogeneous. The term "buffered solutes" only refers to the concept of acid-buffering in infusion fluids but this does not necessarily imply that the solutes have similar physiological impacts. The currently available data indicate that balanced infusates might have some advantages; however, evidence still is inconclusive. Taking the available evidence together, there is no single fluid that is superior for all patients and settings, because all currently available infusates have distinct differences, advantages and disadvantages; therefore, it seems inevitable to abandon the "one fluid for all" strategy towards a more differentiated and patient-centered approach to fluid therapy in the critically ill.

The Effect of a Surgery-Specific Cardiac Output–Guided Haemodynamic Algorithm on Outcomes in Patients Undergoing Pancreaticoduodenectomy in a High-Volume Centre: A Retrospective Comparative Study

In this retrospective observational study performed in a high-volume hepatobiliary–pancreatic unit, we evaluated the effect of a surgery-specific goal-directed therapy (GDT) physiologic algorithm on complications and length of hospital stay. We compared patients who underwent pancreaticoduodenectomy with either a standardised Enhanced Recovery After Surgery program (usual care group), or a standardised Enhanced Recovery After Surgery program in combination with a surgery-specific cardiac output–guided algorithm (GDT group). We included 145 consecutive patients: 47 in the GDT group and 98 in the usual care group. Multivariable associations between GDT and lengths of stay and complications were investigated using negative binomial regression. Postoperative complications were common and occurred at similar frequencies amongst the GDT and usual care groups: 64% versus 68% respectively, P=0.71; odds ratio 0.82; (95% confidence interval 0.39–1.70). There were fewer cardiorespiratory complications in the GDT group. Median (interquartile range) length of hospital stay was ten days (8.0–14.0) in the GDT group compared to 13 days (8.8–21.3) in the usual care group, P=0.01. Median (interquartile range) total intraoperative fluid was 3,000 ml (2,050–4,175) in the GDT group compared to 4,500 ml (3,275–5,325) in the usual care group, P <0.0001; but by day one, the median (interquartile range) fluid balance was similar (1,198 ml [700–1,729] in the GDT group versus 977 ml [419–2,044] in the usual care group, P=0.96). Use of vasoactive medications was higher in the GDT group. In our patients undergoing pancreaticoduodenectomy, GDT was associated with restrictive intraoperative fluid intervention, fewer cardiorespiratory complications and a shorter hospital length of stay compared to usual care. However, we could not exclude an influence of surgical caseload, which we have previously found to be an important variable. We also could not relate the increased hospital length of stay to cardiorespiratory complications in individual patients. Therefore, these observational retrospective findings would require confirmation in a prospective randomised study.

Assessment of Pulmonary Edema: Principles and Practice

Pulmonary edema increasingly is recognized as a perioperative complication affecting outcome. Several risk factors have been identified, including those of cardiogenic origin, such as heart failure or excessive fluid administration, and those related to increased pulmonary capillary permeability secondary to inflammatory mediators. Effective treatment requires prompt diagnosis and early intervention. Consequently, over the past 2 centuries a concentrated effort to develop clinical tools to rapidly diagnose pulmonary edema and track response to treatment has occurred. The ideal properties of such a tool would include high sensitivity and specificity, easy availability, and the ability to diagnose early accumulation of lung water before the development of the full clinical presentation. In addition, clinicians highly value the ability to precisely quantify extravascular lung water accumulation and differentiate hydrostatic from high permeability etiologies of pulmonary edema. In this review, advances in understanding the physiology of extravascular lung water accumulation in health and in disease and the various mechanisms that protect against the development of pulmonary edema under physiologic conditions are discussed. In addition, the various bedside modalities available to diagnose early accumulation of extravascular lung water and pulmonary edema, including chest auscultation, chest roentgenography, lung ultrasonography, and transpulmonary thermodilution, are examined. Furthermore, advantages and limitations of these methods for the operating room and intensive care unit that are critical for proper modality selection in each individual case are explored.

Prospective Randomized Controlled Trial of Liberal Vs Restricted Perioperative Fluid Management in Patients Undergoing Pancreatectomy

OBJECTIVE

The aim of this study is to examine, by a prospective randomized controlled trial, the influence of liberal (LIB) vs restricted (RES) perioperative fluid administration on morbidity following pancreatectomy.

SUMMARY OF BACKGROUND DATA

Randomized controlled trials in patients undergoing major intra-abdominal surgery have challenged the historical use of LIB fluid administration, suggesting that a more restricted regimen may be associated with fewer postoperative complications.

METHODS

Patients scheduled to undergo pancreatic resection were consented for randomization to a LIB (n = 164) or RES (n = 166) perioperative fluid regimen. Sample size was designed with 80% power to decrease Grade 3 complications from 35% to 21%.

RESULTS

Between July 2009 and July 2015, we randomized 330 patients undergoing pancreaticoduodenectomy (PD, n = 218), central (n = 16), or distal pancreatectomy (DP, n = 96). Patients were equally distributed for all demographic and intraoperative characteristics. Intraoperatively, LIB patients received crystalloid 12 mL/kg/h and RES patients 6 mL/kg/h. Cumulative crystalloid given (median, range, mL) days 0 to 3 was LIB: 12,252 (6600 to 21,365), RES 7808 (2700 to 16,274) P < 0.0001. Sixty-day mortality was 2 of 330 (0.6%). Median operative time for PD was 227 minutes (105 to 462) and DP 150 (44 to 323). Grade 3 complications occurred in 20% of LIB and 27% of RES patients (P = 0.6). Median length of stay was 7 and 5 days for PD and DP, respectively, in both arms.

CONCLUSIONS

In a high volume institution, major perioperative complications from pancreatic resection were not significantly influenced by fluid regimens that differed approximately 1.6-fold.

Restrictive versus liberal fluid therapy in major abdominal surgery (RELIEF): rationale and design for a multicentre randomised trial

INTRODUCTION

The optimal intravenous fluid regimen for patients undergoing major abdominal surgery is unclear. However, results from many small studies suggest a restrictive regimen may lead to better outcomes. A large, definitive clinical trial evaluating perioperative fluid replacement in major abdominal surgery, therefore, is required.

METHODS/ANALYSIS

We designed a pragmatic, multicentre, randomised, controlled trial (the RELIEF trial). A total of 3000 patients were enrolled in this study and randomly allocated to a restrictive or liberal fluid regimen in a 1:1 ratio, stratified by centre and planned critical care admission. The expected fluid volumes in the first 24 hour from the start of surgery in restrictive and liberal groups were ≤3.0 L and ≥5.4 L, respectively. Patient enrolment is complete, and follow-up for the primary end point is ongoing. The primary outcome is disability-free survival at 1 year after surgery, with disability defined as a persistent (at least 6 months) reduction in functional status using the 12-item version of the World Health Organisation Disability Assessment Schedule.

ETHICS/DISSEMINATION

The RELIEF trial has been approved by the responsible ethics committees of all participating sites. Participant recruitment began in March 2013 and was completed in August 2016, and 1-year follow-up will conclude in August 2017. Publication of the results of the RELIEF trial is anticipated in early 2018.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier NCT01424150.

Impact of perioperative fluid administration on early outcomes after pancreatoduodenectomy: A meta-analysis

BACKGROUND

Pancreatoduodenectomy (PD) remains a technically challenging surgical procedure with morbidity rates ranging between 30 and 50%. It is suggested that the liberal use of fluids is associated with a poor perioperative outcome. This review examines the impact of fluid administration on outcomes after PD.

METHODS

A literature search was conducted using the MEDLINE, EMBASE and PubMed database (June 1966-June 2016). Studies identified were appraised with standard selection criteria. Data points were extracted and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Eleven studies, seven retrospective trials and four randomized control trials comprising 2842 patients were included. Seven studies were meta-analyzed. There was no difference in length of hospital stay (P = 0.25), pancreas specific complications (P = 0.20), pulmonary (P = 0.58), cardiovascular (P = 0.75), gastrointestinal (P = 0.49), hepatobiliary (P = 0.53), urogenital (P = 0.42), wound complication (P = 0.79), reoperation rate (P = 0.69), overall morbidity (P = 0.18), major morbidity (P = 0.91), 30-day mortality (P = 0.07) and 90-day mortality (P = 0.58) in low or high fluid groups.

CONCLUSION

The current available data fails to demonstrate an association between the amount of perioperative intravenous fluid administration and postoperative complications in patients undergoing PD.

Renal water conservation determines the increase in body weight after surgery: A randomized, controlled trial

Background:

The present study was undertaken to identify factors that correlate with the gain in body weight after surgery.

Methods:

Twenty-one patients (median age of 49 years) were randomized to receive either Ringer × s acetate or 6% dextran 70 as their first infusion fluid during cholecystectomy or hysterectomy. Each patient's body weight was measured before the surgery and on the first postoperative morning. Blood and urine samples were analyzed for signs of stress, inflammation, and kidney injury. The fluid retention index (FRI), which reflects how strongly the kidneys excrete or retain fluid, was also calculated.

Results:

The body weight increased by a median of 0.4 kg in the crystalloid fluid group and by 1.0 kg in the colloid fluid group (maximum 2.5 kg, P < 0.01). This difference was due to less urinary excretion after surgery in the colloid group (P < 0.03). The increase in body weight did not correlate with the infused fluid volume, the plasma concentrations of C-reactive protein or cortisol, or the urinary excretion of albumin, cortisol, or neutrophil gelatinase-associated lipocalin. However, the body weight increased with the postoperative FRI score (r = 0.64; P < 0.003) and with the surgery-induced change in FRI score (r = 0.72; P < 0.002).

Conclusion:

How strongly the kidneys excrete or retain fluid, which can be assessed by urine sampling, was the strongest indicator of the increase in body weight during the day of surgery. The amount of fluid alone did not correlate with the gain in body weight.

Initial 12-h operative fluid volume is an independent risk factor for pleural effusion after hepatectomy

Pleural effusion after hepatectomy is associated with significant morbidity and prolonged hospital stays. Several studies have addressed the risk factors for postoperative pleural effusion. However, there are no researches concerning the role of the initial 12-h operative fluid volume. The aim of this study was to evaluate whether the initial 12-h operative fluid volume during liver resection is an independent risk factor for pleural effusion after hepatectomy. In this study, we retrospectively analyzed clinical data of 470 patients consecutively undergoing elective hepatectomy between January 2011 and December 2012. We prospectively collected and retrospectively analyzed baseline and clinical data, including preoperative, intraoperative, and postoperative variables. Univariate and multivariate analyses were carried out to identify whether the initial 12-h operative fluid volume was an independent risk factor for pleural effusion after hepatectomy. The multivariate analysis identified 2 independent risk factors for pleural effusion: operative time [odds ratio (OR)=10.2] and initial 12-h operative fluid volume (OR=1.0003). Threshold effect analyses revealed that the initial 12 h operative fluid volume was positively correlated with the incidence of pleural effusion when the initial 12-h operative fluid volume exceeded 4636 mL. We conclude that the initial 12-h operative fluid volume during liver resection and operative time are independent risk factors for pleural effusion after hepatectomy. Perioperative intravenous fluids should be restricted properly.

Intraoperative lung ultrasound: A clinicodynamic perspective

In the era of evidence-based medicine, ultrasonography has emerged as an important and indispensable tool in clinical practice in various specialties including critical care. Lung ultrasound (LUS) has a wide potential in various surgical and clinical situations for timely and easy detection of an impending crisis such as pulmonary edema, endobronchial tube migration, pneumothorax, atelectasis, pleural effusion, and various other causes of desaturation before it clinically ensues to critical level. Although ultrasonography is frequently used in nerve blocks, airway handling, and vascular access, LUS for routine intraoperative monitoring and in crisis management still necessitates recognition. After reviewing the various articles regarding the use of LUS in critical care, we found, that LUS can be used in various intraoperative circumstances similar to Intensive Care Unit with some limitations. Except for few attempts in the intraoperative detection of pneumothorax, LUS is hardly used but has wider perspective for routine and crisis management in real-time. If anesthesiologists add LUS in their routine monitoring armamentarium, it can assist to move a step ahead in the dynamic management of critically ill and high-risk patients.

Common Pitfalls in Anesthesia for Noncardiac Thoracic Surgery

Over the past few decades, major surgical procedures involving the thorax have become commonplace at most larger medical facilities. Advances in perioperative care have allowed surgeons to perform increasingly complex procedures. These procedures are being performed on more seriously ill patients who are at increased risk for significant complications. Recent advances should help the anesthesiologist avoid some of the pitfalls in managing these complex patients. Preoperative assessment aids in the identification of patients at highest risk for intraoperative and postoperative events. Particular attention is given to myasthenia gravis, as thymectomy is among the most common surgical procedures that are performed in these patients. Aggressive pain control techniques, including neuraxial opioids and patient-controlled analgesia, where appropriate, not only improve patient comfort but can improve postoperative pulmonary function. Advances in techniques for providing one-lung ventilation allow the anesthesiologist more options to individualize management for each clinical scenario. Careful fluid management may help to minimize the risk of postoperative pulmonary complications. A basic understanding of video-assisted thoracic surgery should help the anesthesiologist provide optimal surgical conditions and perioperative care. Recent advances demand a greater role for the anesthesiologist if the best outcomes are to be achieved in patients undergoing thoracic procedures.

Retrospective evaluation of fluid overload and relationship to outcome in critically ill dogs

OBJECTIVE

To determine if critically ill dogs have an increased risk of fluid overload (FO) during hospitalization compared to less ill dogs, and to determine if FO is associated with increased mortality during hospitalization.

DESIGN

Observational, case-control study.

SETTING

University teaching hospital.

ANIMALS

Thirty-four critically ill dogs and 15 comparatively healthy stable postoperative dogs with neuro-orthopedic disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data recorded included underlying disease, body weight, and APPLEfast score at admission, single-day and composite APPLEfull scores during hospitalization, total fluid volume administered (L), total fluid volume output (L), and outcome. Percent FO (%FO) was calculated using the equation 100 × ([fluid volume administered - fluid volume lost]/1000 mL/L) - (% dehydration at admission), with fluid volume expressed as mL/kg of baseline body weight. Critically ill dogs developed greater %FO during hospitalization compared to stable postoperative dogs (12.1 ± 11.7% vs 0.5 ± 5.2%, P = 0.001), and half (8 out of 16) of the dogs with %FO ≥ 12% died. Composite APPLEfull scores were weakly positively correlated with %FO, whereas APPLEfast and single-day APPLEfull scores recorded at admission were not. The odds ratio for death was 1.08 for every percent increase in FO during hospitalization (95% confidence limits 1.012-1.59, P = 0.02).

CONCLUSIONS

Critically ill dogs are at increased risk for FO during hospitalization, and a weak but significant association exists between %FO, illness severity, and mortality. Prospective studies are warranted to confirm the findings of this retrospective study.

To use or not to use hydroxyethyl starch in intraoperative care: are we ready to answer the 'Gretchen question'?

PURPOSE OF REVIEW

The decision of the European Medicines Agency (EMA) against the use of hydroxyethyl starch (HES)-based volume replacement solutions in critically ill patients has led to a general uncertainty when dealing with HES-based solutions, even though HES-containing solutions can still be used for the treatment of hypovolaemia caused by acute (sudden) blood loss. This review discusses current evidence of the intraoperative use of HES-based solutions.

RECENT FINDINGS

HES solutions are often criticized for possible side-effects on the kidney, the coagulation system or tissue storage. Relevant differences exist between modern 6% HES 130/0.4 and older generation of starches. Because of pathophysiological differences between elective surgery and critical illness, the evidence on renal injury and coagulation impairment with HES administration cannot be generalized. Current data suggest that there is no clinically relevant impact of 6% HES 130/0.4 administration on perioperative renal function and coagulation. Over-resuscitation is a frequent problem associated with adverse outcomes. Due to the higher volume effect, fluid overload with HES is probably more harmful than with crystalloids, whereas goal-directed use of HES may be able to reduce intraoperative fluid accumulation and overload.

SUMMARY

The use of 6% HES 130/0.4 in elective surgery patients is associated with reduced fluid accumulation and no clinically relevant difference in bleeding or the rate of acute kidney injury as compared with crystalloid use alone. Current data do not allow a conclusion on mortality. As they provide no benefit, older starch preparations should not be used.

A novel approach to modeling acute normovolemic hemodilution

Acute normovolemic hemodilution (ANH) was introduced as a blood conservation technique to reduce patient exposure to allogenic blood transfusion during surgery. Despite years of research and experience, the best practice procedure, efficacy and safety of ANH remain in question. In this work, a numerical model is developed for the ANH procedure based upon a multi-compartmental, fluid model of the body. The model also analyzes the most commonly used acellular fluids for ANH or for fluid therapy following hemorrhage. The model allows user input of critical ANH parameters, providing the ability to simulate the patient׳s response in real time to many clinical scenarios, using various types of resuscitation fluids. First, the patient׳s response to a representative, clinical ANH protocol and surgery was simulated. Then, the effect of several variables was investigated including: type/amount of resuscitation fluid, number of blood units collected during ANH, and amount of surgical blood loss. Our simulations highlighted the importance of osmotic molecules within the blood in preventing excessive fluid retention and initiating fluid clearance after surgery. The developed model can be utilized as a tool to simulate and optimize a variety of proposed protocol related to the ANH procedure and surgery. It can also be utilized as an educational or training tool to become familiar with the ANH procedure.

Fluid absorption and the ethanol monitoring method

BACKGROUND

Fluid absorption is a well-known complication of endoscopic surgeries, such as transurethral prostatic resection and transcervical endometrial resection. Absorption of electrolyte-free fluid in excess of 1 L, which occurs in 5% to 10% of the operations, markedly increases the risk of adverse effects from the cardiovascular and neurological systems. Absorption of isotonic saline, which is used with the new bipolar resection technique, will change the scenario of adverse effects in a yet unknown way. Hyponatremia no longer occurs, but marking the saline with ethanol reveals that fluid absorption occurs just as much as with monopolar prostate resections.

METHODS

Ethanol monitoring is a method for non-invasive indication and quantification of fluid absorption that has been well evaluated. By using an irrigating fluid that contains 1% of ethanol, updated information about fluid absorption can be obtained at any time perioperatively by letting the patient breathe into a hand-held alcolmeter.

RESULTS

Regression equations and nomograms with variable complexity are available for estimating how much fluid has been absorbed, both when the alcolmeter is calibrated to show the blood ethanol level and when it is calibrated to show the breath ethanol concentration. Examples of how such estimations should be performed are given in this review article.

CONCLUSIONS

The difficulty is that the anesthesiologist must be aware of how the alcolmeter is calibrated (for blood or breath) and be able to distinguish between the intravascular and extravascular absorption routes, which give rise to different patterns and levels of breath ethanol concentrations.

Assessment of Stroke Volume Variation Perioperatively by Using Arterial Pressure with Cardiac Output

OBJECTIVE

To observe the sensitivity of stroke volume variation (SVV) for assessing volume change during induction period of general anesthesia.

METHODS

Patients who underwent orthopaedic surgery under general anesthesia and mechanical ventilation were divided into two groups randomly. Patients in the group Ⅰwere subjected to progressive central hypovolemia and correction of hypovolemia sequentially; patients in the Group Ⅱ were exposed to hypervolemia alone. Each step was implemented after 5 minutes when the hemodynamics was stable. SVV and cardiac index (CI) were recorded, and Pearson's product-moment correlation was used to analyze correlation between SVV and CI.

RESULTS

Forty patients were included in this study, 20 cases in each group. For group Ⅰ patients, SVV was increased significantly along with blood volume reduction, and changes in CI were negatively correlated with changes in SVV (r=-0.605, P<0.01); SVV decreased significantly along with correction of blood volume; changes in CI were negatively correlated with changes in SVV (r=-0.651, P<0.01). For group Ⅱ patients, along with blood volume increase, SVV did not change significantly; changes in CI revealed no significant correlation with changes in SVV (r=0.067, P>0.05).

CONCLUSION

SVV is a useful indicator for hypovolemia, but not for hypervolemia.

[Optimization of infusion therapy in large abdominal operations]

Volume and consist of infusion therapy determine in many respects postoperative period in patients who underwent large abdominal operations. Purposeful infusion therapy controlled according to monitoring of stroke volume variability is perspective. It was proved that evaluation of this parameter allows to optimize consist and volume of transfused solutions intraoperatively. Use of purposeful infusion therapy was accompanied by decreasing of number of postoperative complications and duration of intensive care unit stay after large abdominal operations.

Ringer's lactate, but not hydroxyethyl starch, prolongs the food intolerance time after major abdominal surgery; an open-labelled clinical trial

Background

The infusion of large amounts of Ringer’s lactate prolongs the functional gastrointestinal recovery time and increases the number of complications after open abdominal surgery. We performed an open-labelled clinical trial to determine whether hydroxyethyl starch or Ringer’s lactate exerts these adverse effects when the surgery is performed by laparoscopy.

Methods

Eighty-eight patients scheduled for major abdominal cancer surgery (83% by laparoscopy) received a first-line fluid treatment with 9 ml/kg of either 6% hydroxyethyl starch 130/0.4 (Voluven) or Ringer’s lactate, just after induction of anaesthesia; this was followed by a second-line infusion with 12 ml/kg of either starch or Ringer’s lactate over 1 hour. Further therapy was managed at the discretion of the attending anaesthetist. Outcome data consisted of postoperative gastrointestinal recovery time, complications and length of hospital stay.

Results

The order of the infusions had no impact on the outcome. Both the administration of ≥ 2 L of Ringer’s lactate and the development of a surgical complication were associated with a longer time period of paralytic ileus and food intolerance (two-way ANOVA, P < 0.02), but only surgical complications prolonged the length of hospital stay (P < 0.001). The independent effect of Ringer’s lactate and complications of food intolerance time amounted to 2 days each. The infusion of ≥ 1 L of hydroxyethyl starch did not adversely affect gastrointestinal recovery.

Conclusions

Ringer’s lactate, but not hydroxyethyl starch, prolonged the gastrointestinal recovery time in patients undergoing laparoscopic cancer surgery. Surgical complications prolonged the hospital stay.

Perioperative fluid therapy: a statement from the international Fluid Optimization Group

BACKGROUND

Perioperative fluid therapy remains a highly debated topic. Its purpose is to maintain or restore effective circulating blood volume during the immediate perioperative period. Maintaining effective circulating blood volume and pressure are key components of assuring adequate organ perfusion while avoiding the risks associated with either organ hypo- or hyperperfusion. Relative to perioperative fluid therapy, three inescapable conclusions exist: overhydration is bad, underhydration is bad, and what we assume about the fluid status of our patients may be incorrect. There is wide variability of practice, both between individuals and institutions. The aims of this paper are to clearly define the risks and benefits of fluid choices within the perioperative space, to describe current evidence-based methodologies for their administration, and ultimately to reduce the variability with which perioperative fluids are administered.

METHODS

Based on the abovementioned acknowledgements, a group of 72 researchers, well known within the field of fluid resuscitation, were invited, via email, to attend a meeting that was held in Chicago in 2011 to discuss perioperative fluid therapy. From the 72 invitees, 14 researchers representing 7 countries attended, and thus, the international Fluid Optimization Group (FOG) came into existence. These researches, working collaboratively, have reviewed the data from 162 different fluid resuscitation papers including both operative and intensive care unit populations. This manuscript is the result of 3 years of evidence-based, discussions, analysis, and synthesis of the currently known risks and benefits of individual fluids and the best methods for administering them.

RESULTS

The results of this review paper provide an overview of the components of an effective perioperative fluid administration plan and address both the physiologic principles and outcomes of fluid administration.

CONCLUSIONS

We recommend that both perioperative fluid choice and therapy be individualized. Patients should receive fluid therapy guided by predefined physiologic targets. Specifically, fluids should be administered when patients require augmentation of their perfusion and are also volume responsive. This paper provides a general approach to fluid therapy and practical recommendations.

The predictive performance of infusion strategy nomogram based on a fluid kinetic model

BACKGROUND

In a previous study, fluid kinetic models were applied to describe the volume expansion of the fluid space by administration of crystalloid and colloid solutions. However, validation of the models were not performed, it is necessary to evaluate the predictive performance of these models in another population.

METHODS

Ninety five consenting patients undergoing elective spinal surgery under general anesthesia were enrolled in this study. These patients were randomly assigned to three fluid groups i.e. Hartmann's solution (H group, n = 28), Voluven® (V group, n = 34), and Hextend® (X group, n = 33). After completion of their preparation for surgery, the patients received a loading and maintenance volume of each fluid predetermined by nomograms based on fluid pharmacokinetic models during the 60-minute use of an infusion pump. Arterial samples were obtained at preset intervals of 0, 10, 20, and 30 min after fluid administration. The predictive performances of the fluid kinetic modes were evaluated using the fractional change of arterial hemoglobin. The relationship between blood-volume dilution and target dilution of body fluid space was also evaluated using regression analysis.

RESULTS

A total of 194 hemoglobin measurements were used. The bias and inaccuracy of these models were -2.69 and 35.62 for the H group, -1.53 and 43.21 for the V group, and 9.05 and 41.82 for the X group, respectively. The blood-volume dilution and target dilution of body-fluid space showed a significant linear relationship in each group (P < 0.05).

CONCLUSIONS

Based on the inaccuracy of predictive performance, the fluid-kinetic model for Hartmann's solution showed better performance than the other models.

Crystalloid administration during trauma resuscitation: does less really equal more?

BACKGROUND

Current direction in trauma resuscitation includes emphasis on minimizing crystalloid, along with early transfusion of blood products. Although evidence suggests that higher crystalloid volume during the first 24 hours is associated with negative outcomes, the effect of crystalloid administration during initial resuscitation remains unclear. The purpose of this study was to evaluate the impact of the ratio of crystalloid to packed red blood cells (C/PRBCs) infused during initial emergency department resuscitation on pulmonary morbidity and mortality.

METHODS

Over 6.5 years at a Level 1 trauma center, prospective data were collected on patients that received more than 1 PRBC unit in the resuscitation room. C/PRBC was defined as the ratio of crystalloid infused in liters to the units of PRBCs transfused in the resuscitation room. Patients were stratified by high ratio (>0.75) versus low ratio (<0.75). Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were determined for the association between C/PRBC group and outcomes, namely, adult respiratory distress syndrome (ARDS), 24-hour mortality, and in-hospital mortality.

RESULTS

A total of 383 patients met study criteria: 192 (50%) in the high-ratio and 191 (50%) in the low-ratio group. Variables associated with in-hospital mortality were Injury Severity Score (ISS) (OR, 1.05; 95% CI, 1.03-1.07), admission base excess (OR, 0.94; 95% CI, 0.90-0.98), and time in the resuscitation room (OR, 1.01; 95% CI, 1.00-1.03). Variables associated with 24-hour mortality were ISS (OR, 1.04; 95% CI, 1.02-1.06) and base excess (OR, 0.95; 95% CI, 0.91-1.00). Only ISS (OR, 1.05; 95% CI, 1.02-1.07) was associated with ARDS. ARDS (OR, 1.43; 95% CI, 0.75-2.73), 24-hour mortality (OR, 0.89; 95% CI, 0.49-1.63), and in-hospital mortality (OR, 0.89; 95% CI, 0.52-1.53) were not associated with C/PRBC.

CONCLUSION

In this cohort of patients receiving PRBC in the resuscitation room, factors related primarily to injury severity were associated with pulmonary morbidity and mortality, but C/PRBC was not. Pertaining to initial resuscitation, the purported benefit of crystalloid limitation was not observed.

LEVEL OF EVIDENCE

Therapeutic study, level IV; prognostic study, level III.

Perioperative management of elderly patients

The older population only represents 13.7% of the US population but has grown by 21% since 2002. The centenarian population is growing at a faster rate than the total US population. This unprecedented growth has significantly increased surgical demand. The establishment of quality and performance improvement data has allowed researchers to focus attention on the older patient population, resulting in an exponential increase in studies. Although there is still much work to be done in this field, overlying themes regarding the perioperative management of elderly patients are presented in this article based on a thorough literature review.

[Accelerated postoperative rehabilitation: multidisciplinary issue. Part 2]

AIM

To discuss the main aspects of multimodal method of accelerated postoperative rehabilitation (fast track surgery).

MATERIAL AND METHODS

The program of accelerated rehabilitation consists of minimization of surgical treatment's stressful influence on patient's organism in all stages of perioperative period. The method implies use of efficient preoperative management, minimally invasive operations, regional anesthesia and short-acting anesthetics, early postoperative rehabilitation.

RESULTS

The program improves the results of surgical treatment, reduces number of complications and cost of treatment, improves the "quality" of hospital stay and satisfaction of meeting with doctors.

Effect of hydroxyethyl starch on postoperative kidney function in patients having noncardiac surgery

BACKGROUND

Whether intraoperative use of hydroxyethyl starch impairs kidney function remains unknown. The authors thus tested the primary hypothesis that Hextend promotes renal injury in surgical patients. Secondarily, the authors evaluated the dose-outcome relationship, in-hospital and 90-day mortality, and whether the relationship between colloid use and acute kidney injury (AKI) depends on baseline risk for AKI.

METHODS

The authors evaluated the data of 44,176 adults without preexisting kidney failure who had inpatient noncardiac surgery from 2005 to 2012. Patients given a combination of colloid and crystalloid were propensity matched on morphometric, and baseline characteristics to patients given only crystalloid. The primary analysis was a proportional odds logistic regression with AKI as an ordinal outcome based on the Acute Kidney Injury Network classification.

RESULTS

The authors matched 14,680 patients receiving colloids with 14,680 patients receiving noncolloids for a total of 29,360 patients. After controlling for potential confounding variables, the odds of developing a more serious level of AKI with Hextend was 21% (6 to 38%) greater than with crystalloid only (P = 0.001). AKI risk increased as a function of colloid volume (P < 0.001). In contrast, the relationship between colloid use and AKI did not differ on baseline AKI risk (P = 0.84). There was no association between colloid use and risk of in-hospital (P = 0.81) or 90-day (P = 0.02) mortality.

CONCLUSION

Dose-dependent renal toxicity associated with Hextend in patients having noncardiac surgery is consistent with randomized trials in critical care patients.