Intra-operative intravenous fluid restriction reduces perioperative red blood cell transfusion in elective cardiac surgery, especially in transfusion-prone patients: a prospective, randomized controlled trial

Effect of blood conservation protocol on the utilisation of blood and outcome of patients undergoing open heart surgery

INTRODUCTION

Cardiac surgery is fraught with increased consumption of blood and blood products. Various strategies for blood conservation have been described. Our aim was to study the impact of a structured blood conservation protocol (BCP) on the utilization of blood and patient outcome.

METHODS

Retrospective analysis of prospectively collected data comparing adult patients undergoing open heart surgery with BCP with those undergoing surgery without BCP. The primary objective was to compare the amount of blood utilized and the hematocrit at discharge. The secondary objective was to compare the parameters of patient outcomes. The level of significance was set at 0.05.

RESULTS

The proportion of patients requiring transfusion (19.1% [9/47] vs 58.9% [33/56]; p < 0.001) and the quantity of blood transfused (12 units vs 45 units; p 0.003) in the BCP group was significantly lower. Interestingly, the hematocrit level at discharge was comparable between the groups (30.9 (4.8) versus 31.8 (2.4), p-0.671). The average cost incurred for transfusing blood in the BCP group was ₹ 370.2 as compared to ₹1165.1 in the other (p < 0.001). BCP reduced the odds of overall blood transfusion by 79.8% (OR 0.202 (0.084-0.485); p < 0.001) and intraoperative blood transfusion by 95.3% (OR 0.047 (0.010-0.213); p < 0.001). The morbidity and mortality were comparable between the groups.

CONCLUSION

Implementing a structured blood conservation protocol in patients undergoing open heart surgery significantly reduces the need for blood transfusion. It also has a promising impact on patient recovery after surgery and significant positive cost implications.

Impact of intraoperative blood products, fluid administration, and persistent hypothermia on bleeding leading to reexploration after cardiac surgery

OBJECTIVE

Risk factors for severe postoperative bleeding after cardiac surgery remain multiple and incompletely elucidated. We evaluated the impact of intraoperative blood product transfusions, intravenous fluid administration, and persistently low core body temperature (CBT) at intensive care unit arrival on risk of perioperative bleeding leading to reexploration.

METHODS

We retrospectively queried our tertiary care center's Society of Thoracic Surgeons Institutional Database for all index, on-pump, adult cardiac surgery patients between July 2016 and September 2022. Intraoperative fluid (crystalloid and colloid) and blood product administrations, as well as perioperative CBT data, were harvested from electronic medical records. Linear and nonlinear mixed models, treating surgeon as a random effect to account for inter-surgeon practice differences, were used to assess the association between above factors and reexploration for bleeding.

RESULTS

Of 4037 patients, 151 (3.7%) underwent reexploration for bleeding. Reexplored patients experienced remarkably greater postoperative morbidity (23% vs 6%, P < .001) and 30-day mortality (14% vs 2%, P < .001). In linear models, progressively increasing IV crystalloid administration (adjusted odds ratio, 1.11, 95% confidence interval, 1.03-1.19) and decreasing CBT on intensive care unit arrival (adjusted odds ratio, 1.20; 95% confidence interval, 1.05-1.37) were associated with greater risk of bleeding leading to reexploration. Nonlinear analysis revealed increasing risk after ∼6 L of crystalloid administration and a U-shaped relationship between CBT and reexploration risk. Intraoperative blood product transfusion of any kind was not associated with reexploration.

CONCLUSIONS

We found evidence of both dilution- and hypothermia-related effects associated with perioperative bleeding leading to reexploration in cardiac surgery. Interventions targeting modification of such risk factors may decrease the rate this complication.

Intraoperative fluid balance and cardiac surgery-associated acute kidney injury: a multicenter prospective study

BACKGROUND

Recent data suggest the regime of fluid therapy intraoperatively in patients undergoing major surgeries may interfere in patient outcomes. The development of postoperative Acute Kidney Injury (AKI) has been associated with both Restrictive Fluid Balance (RFB) and Liberal Fluid Balance (LFB) during non-cardiac surgery. In patients undergoing cardiac surgery, this influence remains unclear. The study objective was to evaluate the relationship between intraoperative RFB vs. LFB and the incidence of Cardiac-Surgery-Associated AKI (CSA-AKI) and major postoperative outcomes in patients undergoing on-pump Coronary Artery Bypass Grafting (CABG).

METHODS

This prospective, multicenter, observational cohort study was set at two high-complexity university hospitals in Brazil. Adult patients who required postoperative intensive care after undergoing elective on-pump CABG were allocated to two groups according to their intraoperative fluid strategy (RFB or LFB) with no intervention.

RESULTS

The primary endpoint was CSA-AKI. The secondary outcomes were in-hospital mortality, cardiovascular complications, ICU Length of Stay (ICU-LOS), and Hospital LOS (H-LOS). After propensity score matching, 180 patients remained in each group. There was no difference in risk of CSA-AKI between the two groups (RR = 1.15; 95% CI, 0.85-1.56, p = 0.36). The in-hospital mortality, H-LOS and cardiovascular complications were higher in the LFB group. ICU-LOS was not significantly different between the two groups. ROCcurve analysis determined a fluid balance above 2500 mL to accurately predict in-hospital mortality.

CONCLUSION

Patients undergoing on-pump CABG with LFB when compared with patients with RFB present similar CSA-AKI rates and ICU-LOS, but higher in-hospital mortality, cardiovascular complications, and H-LOS.

Near Infrared Spectroscopy in Anemia Detection and Management: A Systematic Review

Red cell transfusions are intended to improve oxygen delivery to tissues. Although studies comparing hemoglobin concentration triggers for transfusion have been done, the hemoglobin threshold for clinical benefit remains uncertain. Direct measurement of tissue oxygenation with non-invasive near infrared spectroscopy has been proposed as a more physiological transfusion trigger, but its clinical role remains unclear. This systematic review examined the role of near infrared spectroscopy for detection of anemia and guiding transfusion decisions. Abstracts were identified up until May 2019 through searches of PubMed, EMBASE and The Web of Science. There were 69 studies meeting the inclusion criteria, most (n = 65) of which were observational studies. Tissue oxygen saturation had been measured in a wide range of clinical settings, with neonatal intensive care (n = 26) and trauma (n = 7) being most common. Correlations with hemoglobin concentration and tissue oxygenation were noted and there were correlations between changes in red cell mass and changes in tissue oxygenation through blood loss or transfusion. The value of tissue oxygenation for predicting transfusion was determined in only four studies, all using muscle oxygen saturation in the adult trauma setting. The overall sensitivity was low at 34% (27%-42%) and while it had better specificity at 78% (74%-82%), differing and retrospective approaches create a high level of uncertainty with respect to these conclusions. There were four prospective randomized studies involving 540 patients, in cardiac and neurological surgery and in neonates that compared near infrared spectroscopy to guide transfusion decisions with standard practice. These showed a reduction in the number of red cells transfused per patient (OR: 0.44 [0.09-0.79]), but not the number of patients who received transfusion (OR: 0.71 [0.46-1.10]), and no change in clinical outcomes. Measuring tissue oxygen saturation has potential to help guide transfusion; however, there is a lack of data upon which to recommend widespread implementation into clinical practice. Standardization of measurements is required and greater research into levels at which tissue oxygenation may lead to adverse clinical outcomes would help in the design of future clinical trials.

Impact of maintenance, resuscitation and unintended fluid therapy on global fluid load after elective coronary artery bypass surgery

INTRODUCTION

Standardized protocols are provided for maintenance and replacement fluid therapy in critically ill patients. However, unintended fluid sources (analgesics, antibiotics and other drugs) are not always taken into account when prescribing intravenous fluid therapy. We evaluated the extent to which maintenance, resuscitation and unintended fluids contributed to total fluid load in elective coronary artery bypass graft patients during their ICU stay.

METHODS

Data on intravenous and oral fluid input and output were retrospectively collected from the electronic medical files.

RESULTS

Sixty patients were included. Maintenance fluids represented 1435 ± 570mL (49%) and 2214 ± 657mL (71%), resuscitation fluids 847 ± 542mL (29%) and 338 ± 559mL (11%), unintended fluids 639 ± 162mL (22%) and 576 ± 285mL (18%) respectively on day 1 and day 2. Mean oral intake increased almost fourfold (from 258mL to 1017mL) on the second day.

CONCLUSION

Postoperative maintenance and resuscitation fluids are responsible for most of the observed total fluid load on the first two days after elective coronary artery bypass graft surgery. Unintended fluid load is underestimated and has to be taken into account during fluid prescription.

Patient blood management in cardiac surgery: Results

OBJECTIVE

The main objective of the study was to evaluate the effect of implementing a blood-saving programme in patients undergoing elective cardiac surgery with an analysis of the transfusion rate and complications.

MATERIALS AND METHODS

A single-centre, observational, retrospective, comparative study which included 604 consecutive patients older than 15 years old undergoing elective cardiac surgery. Two groups of patients were created according to whether or not they were included in a blood-saving protocol, and analysed between December 2012 and July 2013 (293 patients, prep group) and April 2015 to May 2016 (311 patients, posp group).

RESULTS

The overall blood product transfusion rate was reduced in the posp group (89.5 vs. 67.6%; P<0.001), as well as individually: red blood cell concentrates (83.6%; P<0.001), fresh frozen plasma (36.2 vs. 21.2%; P<0.001), platelets (40.8 vs. 32.7; P<0.001). By contrast, fibrinogen use increased from 16.4 to 49% (P<0.001). Postoperative complications were similar in both groups, except for pulmonary complications (57.8 vs. 43.1%; P<0.001). Length of hospital stay was similar in both groups except in the Critical Care Unit with longer stay for the prep group (5.81±8.00 vs. 4.18±4.38; P=0.002). Mortality did not change.

CONCLUSIONS

The implementation of a blood-saving programme in the cardiac surgery area has favourable consequences, such as a saving in blood product and a reduction of pulmonary complications, although without decreasing the mortality rate.

Is the use of hydroxyethyl starch as priming solution during cardiac surgery advisable? A randomized, single-center trial

Introduction:

The use of cardiopulmonary bypass (CPB) leads to increased fluid filtration and edema. The use of artificial colloids to counteract fluid extravasation during cardiac surgery is controversial. Beneficial effects on global fluid loading, leading to better cardiac performance and hemodynamics, have been claimed. However, renal function and coagulation may be adversely affected, with unfavorable impact on outcome following cardiac surgery.

Methods:

Forty patients were randomly allocated to study groups receiving either acetated Ringer’s solution (CT group) or hydroxyethyl starch (HES group, Tetraspan®) as CPB priming solution. Fluid balance, bleeding and hemodynamics, including cardiac output, were followed postoperatively. The occurrence of acute kidney injury was closely registered.

Results:

Two patients were excluded from further analyzes due to surgical complications. Fluid accumulation was attenuated in the HES group (3374 (883) ml) compared with the CT group (4328 (1469) ml) (p=0.024). The reduced perioperative fluid accumulation was accompanied by an increased cardiac index immediately after surgery (2.7 (0.4) L/min/m2 in the HES group and 2.1 (0.3) L/min/m2 in the CT group (p<0.001)). No increase in bleeding could be demonstrated in the HES group. Three patients, all of them in the HES group, experienced acute kidney injury postoperatively.

Conclusions:

CPB priming with HES solution lowers fluid loading during bypass and improves cardiac function in the early postoperative period. The manifestation of acute kidney injury exclusively in the HES group of patients raises doubts about the use of HES products in conjunction with cardiac surgery. ( https://clinicaltrials.gov/ct2/show/NCT01511120 )

Restrictive intraoperative fluid optimisation algorithm improves outcomes in patients undergoing pancreaticoduodenectomy: A prospective multicentre randomized controlled trial

We aimed to evaluate perioperative outcomes in patients undergoing pancreaticoduodenectomy with or without a cardiac output goal directed therapy (GDT) algorithm. We conducted a multicentre randomised controlled trial in four high volume hepatobiliary-pancreatic surgery centres. We evaluated whether the additional impact of a intraoperative fluid optimisation algorithm would influence the amount of fluid delivered, reduce fluid related complications, and improve length of hospital stay. Fifty-two consecutive adult patients were recruited. The median (IQR) duration of surgery was 8.6 hours (7.1:9.6) in the GDT group vs. 7.8 hours (6.8:9.0) in the usual care group (p = 0.2). Intraoperative fluid balance was 1005mL (475:1873) in the GDT group vs. 3300mL (2474:3874) in the usual care group (p<0.0001). Total volume of fluid administered intraoperatively was also lower in the GDT group: 2050mL (1313:2700) vs. 4088mL (3400:4525), p<0.0001 and vasoactive medications were used more frequently. There were no significant differences in proportions of patients experiencing overall complications (p = 0.179); however, fewer complications occurred in the GDT group: 44 vs. 92 (Incidence Rate Ratio: 0.41; 95%CI 0.24 to 0.69, p = 0.001). Median (IQR) length of hospital stay was 9.5 days (IQR: 7.0, 14.3) in the GDT vs. 12.5 days in the usual care group (IQR: 9.0, 22.3) for an Incidence Rate Ratio 0.64 (95% CI 0.48 to 0.85, p = 0.002). In conclusion, using a surgery-specific, patient-specific goal directed restrictive fluid therapy algorithm in this cohort of patients, can justify using enough fluid without causing oedema, yet as little fluid as possible without causing hypovolaemia i.e. “precision” fluid therapy. Our findings support the use of a perioperative haemodynamic optimization plan that prioritizes preservation of cardiac output and organ perfusion pressure by judicious use of fluid therapy, rational use of vasoactive drugs and timely application of inotropic drugs. They also suggest the need for further larger studies to confirm its findings.

Reducing inflow occlusion, occlusion duration and blood loss during hepatic resections

BACKGROUND

To assess the changes in blood loss during hepatic resection with improved haemostatic devices such as a bipolar sealing device and a topical haemostatic agent.

METHODS

This retrospective clinical study of prospectively collected data will assess hepatic resections performed by a single surgeon between 2005 and 2013, with the introduction of the two haemostatic techniques in 2009.

RESULTS

A total of 371 hepatic resections (214 from 2005 to 2008 and 157 from 2009 to 2013) were included in this study. Compared with the conventional hepatic resection (2005-2008), the use of haemostatic techniques (2009-2013) significantly reduced the need for inflow occlusion (OR: 0.37, 95% CI: 0.24-0.57, P < 0.001), overall occlusion time (20.8 min versus 25.9 min, P = 0.04) and transfusion requirement (4.6% versus 12%, OR: 0.35, 95% CI: 0.14-0.90, P = 0.02). Mean overall blood loss was reduced post-2009; however, the decrease was not statistically different (401.3 mL versus 470.8 mL, P = 0.27). Subgroup analysis revealed that blood loss was more than halved post-2009 compared with pre-2009 for patients who received pre-operative chemotherapy (324.6 mL versus 738.5 mL, P = 0.005).

CONCLUSION

The use of a bipolar sealing device and a topical haemostatic agent reduces the need for inflow occlusion, overall occlusion time and transfusions in all patients compared with conventional hepatic resections.

Postoperative Critical Care of the Adult Cardiac Surgical Patient. Part I: Routine Postoperative Care

OBJECTIVES

Cardiac surgery, including coronary artery bypass, cardiac valve, and aortic procedures, is among the most common surgical procedures performed in the United States. Successful outcomes after cardiac surgery depend on optimum postoperative critical care. The cardiac intensivist must have a comprehensive understanding of cardiopulmonary physiology and the sequelae of cardiopulmonary bypass. In this concise review, targeted at intensivists and surgeons, we discuss the routine management of the postoperative cardiac surgical patient.

DATA SOURCE AND SYNTHESIS

Narrative review of relevant English-language peer-reviewed medical literature.

CONCLUSIONS

Critical care of the cardiac surgical patient is a complex and dynamic endeavor. Adequate fluid resuscitation, appropriate inotropic support, attention to rewarming, and ventilator management are key components. Patient safety is enhanced by experienced personnel, a structured handover between the operating room and ICU teams, and appropriate transfusion strategies.

Effect of priming solution and ultrafiltration on post-operative bleeding and blood transfusion in cardiac surgery. Randomized controlled trial

OBJECTIVE

Assess the effectiveness of priming the extracorporeal circulation system with albumin-mannitol combined with ultrafiltration during extracorporeal circulation to reduce post-operative bleeding and transfusion requirements in heart surgery, as well as its impact on the fluid balance, coagulation and hematocrit parameters, re-operation for bleeding, ICU, and hospital length of stay.

MATERIAL AND METHODS

A total of 134 patients scheduled for heart surgery were randomized to receive Ringer's lactate 1,500mL in the priming reservoir (group C), or mannitol 20% 250mL, albumin 20% 150mL and Ringer's lactate 1,100mL combined with ultrafiltration (group T). Bleeding volume, transfusions, fluid balance, coagulation, and hematology parameters were determined until 48h in the post-operative period.

RESULTS

There was a reduction of postoperative bleeding in group T, 1,165±789mL vs 992±662mL (P=.17), and red blood cell concentrate transfusions, 694±843mL vs 413±605mL (P=.03). Intra-operative and post-operative fluid balance was significantly less positive in group T, with an overall balance of 2,292±2,152mL vs 5,388±2,834mL (P<.001). There were higher values of hemoglobin and hematocrit, intraoperative (P<.001), on admission to ICU (P=.001), and at 6h (P=.05) in group T, and lower INR at 6h (P=.01) and 24h (P=.02). Re-operation rate and length of stay in ICU were higher in group C, but not statiscally significant.

CONCLUSIONS

The priming of extracorporeal reservoir with mannitol, albumin, and Ringer's lactate, combined with ultrafiltration, significantly improves intra- and post-operative fluid balance, resulting in a reduction in blood transfusions, with no significant decrease in post-operative bleeding, re-operation bleeding rate, and length of stay in the ICU.

Fluid management in the cardiothoracic intensive care unit: diuresis--diuretics and hemofiltration

PURPOSE OF REVIEW

The present review discusses the current concepts of fluid management in cardiothoracic surgery, and its clinical implications with special reference to organ-related complications and their prevention.

RECENT FINDINGS

Current strategies in fluid management for cardiothoracic patients, various fluid formulation, and the preventive strategies for minimizing fluid-related complications are described, with particular reference to new discoveries and controversies that have arisen from recent literature.

SUMMARY

The optimal fluid management in cardiothoracic patients has not been settled. Results of recent clinical published trials highlight the need for minimizing fluid administration and attempting to use diuretics to achieve a negative fluid, although hypovolemia and hypoperfusion should be carefully considered. An individualized optimization of fluid status, using goal-directed therapy, has emerged as a possible preferable approach. The old debate between crystalloid and colloid solutions has been partially solved, as some colloids have demonstrated deleterious effect on renal function and coagulation system. Various preventive strategies have also emerged for minimizing fluid-related complications.

Perioperative restricted fluid therapy preserves immunological function in patients with colorectal cancer

AIM: To investigate the effect of perioperative restricted fluid therapy on circulating CD4⁺/CD8⁺ T lymphocyte ratio, percentage of regulatory T cells (Treg) and postoperative complications in patients with colorectal cancer.

METHODS: A total of 185 patients met the inclusion criteria and were included in the randomized clinical trial. These patients were divided into two groups according to receipt of either perioperative standard (S, n = 89) or restricted (R, n = 96) fluid therapy. Clinical data of these patients were collected in this prospective study. Perioperative complications and cellular immunity changes (CD4⁺/CD8⁺ and Treg) were analyzed comparatively between the two groups.

RESULTS: Both during surgery and on postoperative days, the total volumes of fluids administered in the R group were significantly lower than those in the S group (1620 ± 430 mL vs 3110 ± 840 mL; 2090 ± 360 mL vs 2750 ± 570 mL; 1750 ± 260 mL vs 2740 ± 490 mL; 1620 ± 310 mL vs 2520 ± 300 mL; P < 0.05). Decreased ratios of circulating CD4⁺/CD8⁺ T lymphocytes (1.47 ± 0.28 vs 2.13 ± 0.26; 1.39 ± 0.32 vs 2.21 ± 0.24; P < 0.05) and Treg percentage values (2.79 ± 1.24 vs 4.26 ± 1.04; 2.46 ± 0.98 vs 4.30 ± 1.12; P < 0.05) were observed after surgery in both groups. However, in the R group, these values restored more quickly starting from postoperative day 2 (1.44 ± 0.24 vs 1.34 ± 0.27; 2.93 ± 1.08 vs 2.52 ± 0.96; P < 0.05). The proportion of patients with complications was significantly lower in the restricted group (36 of 89 vs 59 of 96, P < 0.01).

CONCLUSION: Perioperative restricted intravenous fluid regimen leads to a low postoperative complication rate and better cellular immunity preservation in patients with colorectal cancer.

Cerebral oximetry in cardiac anesthesia

Cerebral oximetry based on near-infrared spectroscopy (NIRS) is increasingly used during the perioperative period of cardiovascular operations. It is a noninvasive technology that can monitor the regional oxygen saturation of the frontal cortex. Current literature indicates that it can stratify patients preoperatively according their risk. Intraoperatively, it provides continuous information about brain oxygenation and allows the use of brain as sentinel organ indexing overall organ perfusion and injury. This review focuses on the clinical validity and applicability of this monitor for cardiac surgical patients.

Monitoring of brain oxygen saturation (INVOS) in a protocol to direct blood transfusions during cardiac surgery: a prospective randomized clinical trial

Background

Blood transfusions are common in cardiac surgery, but have been associated with increased morbidity and long-term mortality. Efforts to reduce blood product use during cardiac surgery include fluid restriction to minimize hemodilution, and protocols to guide transfusion decisions. INVOS is a modality that monitors brain tissue oxygen saturation, and could be useful in guiding decisions to transfuse. However, the role of INVOS (brain tissue oxygen saturation) as part of an algorithm to direct blood transfusions during cardiac surgery has not been evaluated. This study was conducted to investigate the value of INVOS as part of a protocol for blood transfusions during cardiac surgery.

Methods

Prospective, randomized, blinded clinical trial, on 150 (75 per group) elective cardiac surgery patients. The study was approved by the Institution Ethics committee and all patients gave written informed consent. Data were initially analyzed based on “intention to treat”, but subsequently were also analyzed “per protocol”.

Results

When protocol was strictly followed (“per protocol analysis”), compared to the control group, significantly fewer patients monitored with INVOS received any blood transfusions (46 of 70 patients in INVOS group vs. 55 of 67 patients in the control group, p = 0.029). Similarly, patients monitored with INVOS received significantly fewer units of red blood cell transfusions intraoperatively (0.20 ± 0.50 vs. 0.52 ± 0.88, p = 0.008) and overall during hospital stay (1.31 ± 1.20 vs. 1.82 ± 1.46, p = 0.024). When data from all patients (including patient with protocol violation) were analyzed together (“intention to treat analysis”), the observed reduction of blood transfusions in the INVOS group was still significant (51 of 75 patients transfused in the INVOS group vs. 63 of 75 patients transfused in the control group, p = 0.021), but the overall number of units transfused per patient did not differ significantly between the groups (1.55 ± 1.97 vs. 1.84 ± 1.41, p = 0.288).

Conclusions

Our data suggest that INVOS could be a useful tool as part of an algorithm to guide decisions for blood transfusion in cardiac surgery. Additional data from rigorous, well designed studies are needed to further evaluate the role of INVOS in guiding blood transfusions in cardiac surgery, and circumvent the limitations of this study.

Trial registration

ClinicalTrials.gov: NCT00879463

The effect of retrograde autologous priming volume on haemodilution and transfusion requirements during cardiac surgery

OBJECTIVES

Many cardiac procedures using cardiopulmonary bypass (CPB) still require intraoperative transfusion. Retrograde autologous priming (RAP) has been introduced to decrease haemodilution and the blood transfusion rate. This study is designed to determine the influence or RAP on intraoperative haematocrit, transfusion and its clinical consequences.

METHODS

The RAP effect was retrospectively studied in 753 patients during contemporary cardiac surgery, targeting a haematocrit of 25%. Multivariate linear regression analysis was performed to identify the independent factors influencing intraoperative haematocrit, transfusion rate and transfusion quantity.

RESULTS

RAP was used in 498 patients and compared with 255 controls. RAP decreased the haemodilution level (nadir haematocrit 26.8 standard deviation [SD] 4.0% in RAP vs 25.8 SD 3.6% in controls; P = 0.001) and transfusion frequency (26.1 vs 33.3%, P = 0.04), despite smaller patients (body surface area [BSA] 1.86 SD 0.20 m(2) vs 1.91 SD 0.21 m(2) in RAP vs controls; P = 0.002) with lower preoperative haematocrit (38.9 SD 4.4% vs 40.5 SD 4.6%; P < 0.001). Optimal RAP volume was overall 475 ml (ROC area 0.55; 95% confidence interval [CI] 0.50-0.60; P = 0.04) and 375 ml in patients with BSA <1.7 m(2) (ROC area 0.63; 95% CI 0.54-0.73; P = 0.008) to decrease the transfusion incidence. Multivariate analysis revealed RAP volume as a significant determinant of nadir haematocrit (β = 0.003, 95% CI 0.002-0.004, P < 0.001) and transfusion rate (odds ratio (OR) = 0.997, 95% CI 0.996-0.999, P < 0.001), independent of BSA, gender and preoperative haematocrit.

CONCLUSIONS

Retrograde autologous priming is an effective adjunct to decrease the blood transfusion rate, coping with the CPB-related haemodilution and its adverse clinical effects. A RAP volume individualized to each patient offers most benefit as part of a multidisciplinary blood conservation approach.

Can anaesthetic technique effect postoperative outcome?

PURPOSE OF REVIEW

Conventional wisdom maintains that multiple aspects of surgical technique and management may affect postoperative outcome, while anaesthetic technique has little long-term effect on patient outcomes. There is accumulating evidence that, on the contrary, anaesthetic management may in fact exert a number of longer-term effects in postoperative outcome. Here, we review the most topical aspects of anaesthetic management which may potentially influence later postoperative outcomes.

RECENT FINDINGS

There is strong evidence that administration of supplemental oxygen and the avoidance of perioperative hypothermia, allogeneic blood transfusion, hyperglycaemia or large swings in blood glucose levels reduces postoperative infection rates. There is also some evidence that the use of regional anaesthesia techniques reduces chronic postsurgical pain and that avoidance of nitrous oxide reduces the long-term risk of myocardial infarction. Current evidence is equivocal regarding the effects of anaesthesia techniques and cancer recurrence. The instigation of perioperative beta-blockade in noncardiac surgery may not reduce perioperative adverse events or improve postoperative cardiovascular risk.

SUMMARY

Further prospective, large-scale human trials with long-term follow-up are required to clarify the association between anaesthesia and cancer recurrence, neurotoxicity and the developing brain and long-term postoperative cognitive dysfunction in the elderly.

Perioperative acute kidney injury

Acute kidney injury (AKI) is a serious complication in the perioperative period, and is consistently associated with increased rates of mortality and morbidity. Two major consensus definitions have been developed in the last decade that allow for easier comparison of trial evidence. Risk factors have been identified in both cardiac and general surgery and there is an evolving role for novel biomarkers. Despite this, there has been no real change in outcomes and the mainstay of treatment remains preventive with no clear evidence supporting any therapeutic intervention as yet. This review focuses on definition, risk factors, the emerging role of biomarkers and subsequent management of AKI in the perioperative period, taking into account new and emerging strategies.

Factors in perioperative care that determine blood loss in liver surgery

OBJECTIVES

Excessive blood loss during liver surgery contributes to postoperative morbidity and mortality and the minimizing of blood loss improves outcomes. This study examines pre- and intraoperative factors contributing to blood loss and identifies areas for improvement.

METHODS

All patients who underwent elective hepatic resection between June 2007 and June 2009 were identified. Detailed information on the pre- and perioperative clinical course was analysed. Univariate and multivariate analyses were used to identify factors associated with intraoperative blood loss.

RESULTS

A total of 175 patients were studied, of whom 95 (54%) underwent resection of three or more segments. Median blood loss was 782 ml. Greater blood loss occurred during major resections and prolonged surgery and was associated with an increase in postoperative complications (P= 0.026). Peak central venous pressure (CVP) of >10 cm H(2)O was associated with increased blood loss (P= 0.01). Although no differences in case mix were identified, blood loss varied significantly among anaesthetists, as did intraoperative volumes of i.v. fluids and transfusion practices.

CONCLUSIONS

This study confirms a relationship between CVP and blood loss in hepatic resection. Intraoperative CVP values were higher than those described in other studies. There was variation in the intraoperative management of patients. Collaboration between surgical and anaesthesia teams is required to minimize blood loss and the standardization of intraoperative anaesthesia practice may improve outcomes following liver surgery.

Management of intraoperative fluid balance and blood conservation techniques in adult cardiac surgery

Blood transfusions are associated with adverse physiologic effects and increased cost, and therefore reduction of blood product use during surgery is a desirable goal for all patients. Cardiac surgery is a major consumer of donor blood products, especially when cardiopulmonary bypass (CPB) is used, because hematocrit drops precipitously during CPB due to blood loss and blood cell dilution. Advanced age, low preoperative red blood cell volume (preoperative anemia or small body size), preoperative antiplatelet or antithrombotic drugs, complex or re-operative procedures or emergency operations, and patient comorbidities were identified as important transfusion risk indicators in a report recently published by the Society of Cardiovascular Anesthesiologists. This report also identified several pre- and intraoperative interventions that may help reduce blood transfusions, including off-pump procedures, preoperative autologous blood donation, normovolemic hemodilution, and routine cell saver use.A multimodal approach to blood conservation, with high-risk patients receiving all available interventions, may help preserve vital organ perfusion and reduce blood product utilization. In addition, because positive intravenous fluid balance is a significant factor affecting hemodilution during cardiac surgery, especially when CPB is used, strategies aimed at limiting intraoperative fluid balance positiveness may also lead to reduced blood product utilization.This review discusses currently available techniques that can be used intraoperatively in an attempt to avoid or minimize fluid balance positiveness, to preserve the patient's own red blood cells, and to decrease blood product utilization during cardiac surgery.