Randomized controlled trial to investigate influence of the fluid challenge on duration of hospital stay and perioperative morbidity in patients with hip fractures

Intra-operative oxygen delivery in infusion volume-optimized patients undergoing laparoscopic colorectal surgery within an enhanced recovery programme: the effect of different analgesic modalities

AIM

Patients undergoing major open surgery who have an indexed oxygen delivery (DO(2) I) > 600 ml/min/m(2) have been shown to have a lower incidence of morbidity and mortality compared with those whose DO(2) I is below this level. Laparoscopy and Trendelenburg positioning cause a reduction in DO(2) I. We aimed to quantify the effect of the type of analgesia on DO(2) I and to correlate the DO(2) I achieved with the incidence of anastomotic leakage in patients undergoing laparoscopic surgery.

METHOD

Following ethical approval, patients were randomized to receive spinal anaesthesia (Group S), epidural analgesia (Group E) or intravenous morphine (Group P) followed by postoperative patient-controlled analgesia (PCA). In addition to standard monitoring, oesophageal Doppler monitoring of the stroke volume allowed directed intravenous fluid therapy. The mean DO(2) I was compared with the anastomotic leakage rate.

RESULTS

Seventy-five patients were recruited (Group S, 27; Group E, 23; Group P, 25). The mean (range) DO(2) I for all patients was 490 (230-750) ml/min/m(2) . The analgesic modality had no effect on DO(2) I. Of the 18 patients with a DO(2) I of < 400 ml/min/m(2) , four (22%) developed anastomotic leakage compared with one (%) of the 57 patients with a DO(2) I of > 400 ml/min/m(2) (P = 0.01).

CONCLUSION

The analgesic modality used had no effect on the DO(2) I achieved. Anastomotic leakage was significantly higher in patients with a DO(2) I of < 400 ml/min/m(2) . A further study assessing the outcome after raising the DO(2) I with inotropes is required.

Descending aortic blood flow during aortic cross-clamp indicates postoperative splanchnic perfusion and gastrointestinal function in patients undergoing aortic reconstruction

BACKGROUND

The purpose of this observational study was to investigate the relationship between splanchnic and renal blood flow during infrarenal aortic cross-clamp (XC) and postoperative gastrointestinal perfusion and function.

METHODS

Descending aortic blood flow (DABF) was continuously monitored with an oesophageal Doppler monitor (Cardio-Q, Deltex Ltd, Chichester, UK) in 31 patients undergoing elective abdominal aortic aneurysm repair. Cardiac output (CO) was determined by indocyanine green dilution before, during, and after XC. Perioperative gastrointestinal perfusion was assessed by gastric intramucosal pH (pHi, Tonocap, GE Healthcare, Helsinki, Finland). Postoperative gastrointestinal recovery was assessed by the number of postoperative days until the patient successfully resumed solid food intake. The relationship between the mean DABF during XC and gastric pHi after XC release and postoperative gastrointestinal recovery was analysed with Spearman's correlation coefficient.

RESULTS

accounted for ∼ 55% of CO during XC and significantly decreased during XC, despite arterial pressure remaining within an optimal range. There were two distinct relationships between DABF during XC and gastric pHi after XC release. Gastric pHi steeply and linearly declined when indexed DABF was below 0.82 litre min(-1) m(-2). Above this critical value, there was no linear relationship between them. The duration of postoperative gastrointestinal dysfunction was inversely correlated with the mean DABF during XC. The best cut-off value of the mean indexed DABF during XC to prevent prolonged gastrointestinal dysfunction was 1.2 litre min(-1) m(-2).

CONCLUSIONS

Decreased DABF during XC associates splanchnic hypoperfusion after XC release and delayed recovery of gastrointestinal function.

Comparison of continuous thoracic epidural with paravertebral block on perioperative analgesia and hemodynamic stability in patients having open lung surgery

BACKGROUND

Epidural analgesia can result in perioperative hypotension in patients having thoracotomy. This randomized prospective study assessed the effects of epidural and paravertebral analgesia on hemodynamics during thoracotomy.

METHODS

Thirty-two patients were randomized to receive either epidural analgesia (n = 16, 0.25% levobupivacaine and 30 μg/kg morphine) or paravertebral block (n = 16; 0.5% levobupivacaine and 30 μg/kg morphine). Oxygen delivery, stroke volume and systemic vascular resistance indices, heart rate, and mean arterial pressure measurements were performed before administration of local anesthetic, after induction of general anesthesia, institution of 1-lung ventilation, first skin incision, retractor placement, lung-inflation maneuver, and at last skin suture. The primary end point was the volume of the colloid infusion necessary to maintain oxygen delivery index of 500 mL/min per squared meter or higher. Postoperative analgesia was provided immediately after surgery by an infusion of 0.125% levobupivacaine and 20 μg/mL morphine in epidural/paravertebral infusion. Pain, rescue-analgesia consumption, arterial pressure, and heart rate were recorded at 6, 24, and 48 hrs after surgery. Administration of anesthesia and data collection were done by research staff blinded to the regional analgesia technique.

RESULTS

The groups did not differ significantly in heart rate, mean arterial blood pressure, or systemic vascular resistance indices. However, to maintain the targeted oxygen delivery index, a greater volume of colloid infusion and phenylephrine were required, respectively, in the epidural than in the paravertebral group (554 ± 50 vs 196 ± 75 mL, P = 0.04; and 40 ± 10 vs 17 ± 4 μg, P = 0.04). Pain intensity before and after respiratory physiotherapy as well as 24 hr rescue piritramide consumption was similar in the epidural (4.1 ± 3.1 mg) and the paravertebral (2.5 ± 1.5 mg) groups (P = 0.14). Systolic blood pressure after 24 and 48 hrs was lower in the epidural group.

CONCLUSIONS

Under the conditions of our study, continuous paravertebral block resulted in similar analgesia but greater hemodynamic stability than epidural analgesia in patients having thoracotomy. Paravertebral block also required smaller volume of colloids and vasopressors to maintain the target oxygen delivery index (DO2I).

Evaluation of fluid responsiveness: is photoplethysmography a noninvasive alternative?

Background. Goal-directed fluid therapy reduces morbidity and mortality in various clinical settings. Respiratory variations in photoplethysmography are proposed as a noninvasive alternative to predict fluid responsiveness during mechanical ventilation. This paper aims to critically evaluate current data on the ability of photoplethysmography to predict fluid responsiveness. Method. Primary searches were performed in PubMed, Medline, and Embase on November 10, 2011. Results. 14 papers evaluating photoplethysmography and fluid responsiveness were found. Nine studies calculated areas under the receiver operating characteristic curves for ΔPOP (>0.85 in four, 0.75–0.85 in one, and <0.75 in four studies) and seven for PVI (values ranging from 0.54 to 0.98). Correlations between ΔPOP/PVI and ΔPP/other dynamic variables vary substantially. Conclusion. Although photoplethysmography is a promising technique, predictive values and correlations with other hemodynamic variables indicating fluid responsiveness vary substantially. Presently, it is not documented that photoplethysmography is adequately valid and reliable to be included in clinical practice for evaluation of fluid responsiveness.

Perioperative fluid management strategies in major surgery: a stratified meta-analysis

BACKGROUND

Both "liberal" and "goal-directed" (GD) therapy use a large amount of perioperative fluid, but they appear to have very different effects on perioperative outcomes. We sought to determine whether one fluid management strategy was superior to the others.

METHODS

We selected randomized controlled trials (RCTs) on the use of GD or restrictive versus liberal fluid therapy (LVR) in major adult surgery from MEDLINE, EMBASE, PubMed (1951 to April 2011), and Cochrane controlled trials register without language restrictions. Indirect comparison between the GD and LVR strata was performed.

RESULTS

A total of 3861 patients from 23 GD RCTs (median sample size = 90, interquartile range [IQR] 57 to 109) and 1160 patients from 12 LVR RCTs (median sample size = 80, IQR36 to 151) were considered. Both liberal and GD therapy used more fluid compared to their respective comparative arm, but their effects on outcomes were very different. Patients in the liberal group of the LVR stratum had a higher risk of pneumonia (risk ratio [RR] 2.2, 95% confidence interval [CI] 1.0 to 4.5), pulmonary edema (RR 3.8, 95% CI 1.1 to 13), and a longer hospital stay than those in the restrictive group (mean difference [MD] 2 days, 95% CI 0.5 to 3.4). Using GD therapy also resulted in a lower risk of pneumonia (RR 0.7, 95% CI 0.6 to 0.9) and renal complications (0.7, 95% CI 0.5 to 0.9), and a shorter length of hospital stay (MD 2 days, 95% CI 1 to 3) compared to not using GD therapy. Liberal fluid therapy was associated with an increased length of hospital stay (4 days, 95% CI 3.4 to 4.4), time to first bowel movement (2 days, 95% CI 1.3 to 2.3), and risk of pneumonia (RR ratio 3, 95% CI 1.8 to 4.8) compared to GD therapy.

CONCLUSION

Perioperative outcomes favored a GD therapy rather than liberal fluid therapy without hemodynamic goals. Whether GD therapy is superior to a restrictive fluid strategy remains uncertain.

The use of LiDCO based fluid management in patients undergoing hip fracture surgery under spinal anaesthesia: neck of femur optimisation therapy - targeted stroke volume (NOTTS): study protocol for a randomized controlled trial

BACKGROUND

Approximately 70,000 patients/year undergo surgery for repair of a fractured hip in the United Kingdom. This is associated with 30-day mortality of 9% and survivors have a considerable length of acute hospital stay postoperatively (median 26 days). Use of oesophageal Doppler monitoring to guide intra-operative fluid administration in hip fracture repair has previously been associated with a reduction in hospital stay of 4-5 days. Most hip fracture surgery is now performed under spinal anaesthesia. Oesophageal Doppler monitoring may be unreliable in the presence of spinal anaesthesia and most patients would not tolerate the probes. An alternative method of guiding fluid administration (minimally-invasive arterial pulse contour analysis) has been shown to reduce length of stay in high-risk surgical patients but has never been studied in hip fracture surgery.

METHODS

Single-centre randomised controlled parallel group trial. Randomisation by website using computer generated concealed tables.

SETTING

University hospital in UK.

PARTICIPANTS

128 patients with acute primary hip fracture listed for operative repair under spinal anaesthesia and aged > 65 years.

INTERVENTION

Stroke volume guided intra-operative fluid management. Continuous measurement of SV recorded by a calibrated cardiac output monitor (LiDCOplus). Maintenance fluid and 250 ml colloid boluses given to achieve sustained 10% increases in stroke volume.

CONTROL GROUP

fluid administration at the responsible (blinded) anaesthetist's discretion. The intervention terminates at the end of the surgical procedure and post-operative fluid management is at the responsible anaesthetist's discretion.

PRIMARY OUTCOME

length of acute hospital stay is determined by a blinded team of clinicians. Secondary outcomes include number of complications and total cost of care. Funding NIHR/RfPB: PB-PG-0407-13073.

TRIAL REGISTRATION NUMBER

TRIAL REGISTRATION

Current Controlled Trials ISRCTN88284896.

Restrictive strategy of intraoperative fluid maintenance during optimization of oxygen delivery decreases major complications after high-risk surgery

Introduction

Optimal fluid management is crucial for patients who undergo major and prolonged surgery. Persistent hypovolemia is associated with complications, but fluid overload is also harmful. We evaluated the effects of a restrictive versus conventional strategy of crystalloid administration during goal-directed therapy in high-risk surgical patients.

Methods

We conducted a prospective, randomized, controlled study of high-risk patients undergoing major surgery. For fluid maintenance during surgery, the restrictive group received 4 ml/kg/hour and the conventional group received 12 ml/kg/hour of Ringer's lactate solution. A minimally invasive technique (the LiDCO monitoring system) was used to continuously monitor stroke volume and oxygen delivery index (DO₂I) in both groups. Dobutamine was administered as necessary, and fluid challenges were used to test fluid responsiveness to achieve the best possible DO₂I during surgery and for 8 hours postoperatively.

Results

Eighty-eight patients were included. The patients' median age was 69 years. The conventional treatment group received a significantly greater amount of lactated Ringer's solution (mean ± standard deviation (SD): 4, 335 ± 1, 546 ml) than the restrictive group (mean ± SD: 2, 301 ± 1, 064 ml) (P < 0.001). Temporal patterns of DO₂I were similar between the two groups. The restrictive group had a 52% lower rate of major postoperative complications than the conventional group (20.0% vs 41.9%, relative risk = 0.48, 95% confidence interval = 0.24 to 0.94; P = 0.046).

Conclusions

A restrictive strategy of fluid maintenance during optimization of oxygen delivery reduces major complications in older patients with coexistent pathologies who undergo major surgery.

Trial registration

ISRCTN: ISRCTN94984995

Cardiac output monitoring to guide fluid replacement in head and neck microvascular free flap surgery-what is current practice in the UK?

Appropriate fluid balance is an important factor in the survival of free flaps, and recently there has been a shift towards more conservative fluid regimens. Several surgical specialties have made extensive use of the relatively non-invasive method of measuring cardiac output (CO) to optimise fluid balance during and after surgery, which has resulted in a shorter hospital stay, but little has been published in head and neck surgery. To ascertain its use in the head and neck we sent a postal questionnaire to the anaesthetic departments of 40 major head and neck units identified from the 2010 database of the British Association of Oral and Maxillofacial Surgeons (BAOMS). Questions were asked about the number of free flaps done in the unit each year, the monitoring of central venous and arterial blood pressure (and inotrope protocols), optimal target variables, and whether CO was monitored (with type of device). Thirty-two units responded (80%). While 26 units (81%) routinely monitored central venous pressure (CVP), CO was monitored in only 3 units (9%). There was a wide range of responses in relation to optimal variables and use of inotropes. As with other specialties, it is likely that CO monitoring will become widely used in head and neck reconstructive surgery. Not only does it enhance fluid optimisation, but it may also reduce hospital stay and morbidity. Appropriate clinical studies are urgently needed to evaluate its use in our specialty.

Esophageal Doppler monitoring during colorectal resection offers cost-effective improvement of hemodynamic control

OBJECTIVES

Hemodynamic control can improve the outcome of surgery. Esophageal Doppler monitoring measures blood flow by ultrasound waves. This work investigates the cost-effectiveness of this procedure during colorectal resection.

METHODS

Meta-analyses of randomized controlled trials of esophageal Doppler monitoring used in colorectal resection were conducted to help determine its cost-effectiveness. An analytical decision model was used to compare the cost-effectiveness of strategies involving conventional clinical assessment with or without the measurement of central venous pressure, with or without esophageal Doppler monitoring. Avoided mortality and avoided major complications were used as measures of clinical effectiveness.

RESULTS

In the meta-analyses comparing conventional clinical assessment plus central venous pressure monitoring with or without esophageal Doppler monitoring, statistically significant differences in total and major complications favoring the use of Doppler were found. No differences were seen in mortality. The use of esophageal Doppler monitoring was associated with lower costs, mainly due to fewer complications, shorter hospital stays and shorter surgery times.

CONCLUSIONS

Although the information regarding the clinical effectiveness of esophageal Doppler monitoring in colorectal resection is limited, strategies including this form of blood flow monitoring may be cost-effective. Further comparisons of Doppler monitoring against other hemodynamic monitoring systems should be undertaken.

Hemodynamic monitoring in sepsis

Arterial waveform analysis that does not require continuous calibration, impedance cardiography, electrical cardiometry, velocity-encoded phase contrast magnetic resonance imaging (MRI), pulsed dye densitometry, noninvasive pulse pressure analysis using tonometry, suprasternal Doppler, partial CO2 rebreathing techniques, and transcutaneous Doppler are just some of the other emerging technologies not described in this review that may be used routinely in the management of sepsis and septic shock in the very near future. These innovative approaches may further increase our ability to optimize patients' fluid status and hemodynamics. We also have ability to monitor the microcirculation. This increasingly sophisticated approach to the management of sepsis and septic shock will hopefully translate into better patient outcomes. However, optimal use of any hemodynamic monitoring requires an understanding of its physiologic underpinnings. Accurate interpretation of the hemodynamic information coupled with a protocolized management algorithm is the cornerstone of an effective resuscitation effort. Many forms of hemodynamic monitoring have emerged over the past 20 to 30 years with no convincing evidence for the superiority of any single techniques (Table 2). The goal of hemodynamic monitoring and optimization is to combat the systemic imbalance between tissue oxygen supply and demand ranging from global tissue hypoxia to overt shock and multiorgan failure. It remains unproven that hemodynamic monitoring of disease progression can effectively change patient outcome. However, despite our increased understanding of sepsis pathophysiology, mortality and morbidity from the disease remains high. Therefore, the search for the optimal parameters in resuscitation and the best way they can be monitored will continue.

Cardiac output assessed by invasive and minimally invasive techniques

Cardiac output (CO) measurement has long been considered essential to the assessment and guidance of therapeutic decisions in critically ill patients and for patients undergoing certain high-risk surgeries. Despite controversies, complications and inherent errors in measurement, pulmonary artery catheter (PAC) continuous and intermittent bolus techniques of CO measurement continue to be the gold standard. Newer techniques provide less invasive alternatives; however, currently available monitors are unable to provide central circulation pressures or true mixed venous saturations. Esophageal Doppler and pulse contour monitors can predict fluid responsiveness and have been shown to decrease postoperative morbidity. Many minimally invasive techniques continue to suffer from decreased accuracy and reliability under periods of hemodynamic instability, and so few have reached the level of interchangeability with the PAC.

Haemodynamic goal-directed therapy and postoperative infections: earlier is better. A systematic review and meta-analysis

Introduction

Infectious complications are the main causes of postoperative morbidity. The early timing of their promoting factors is the rationale for perioperative strategies attempting to reduce them. Our aim was to determine the effects of perioperative haemodynamic goal-directed therapy on postoperative infection rates.

Methods

We performed a systematic review and meta-analysis. MEDLINE, EMBASE, The Cochrane Library and the DARE databases were searched up to March 2011. Randomised, controlled trials of major surgery in adult patients managed with perioperative goal-directed therapy or according to routine haemodynamic practice were included. Primary outcome measure was specific type of infection.

Results

Twenty-six randomised, controlled trials with a combined total of 4,188 participants met our inclusion criteria. Perioperative goal-directed therapy significantly reduced surgical site infections (pooled OR 0.58, 95% CI 0.46 to 0.74; P < 0.0001), pneumonia (pooled OR 0.71, 95% CI 0.55 to 0.92; P = 0.009), and urinary tract infections (pooled OR 0.44, 95% CI 0.22 to 0.84; P = 0.02). A significant benefit was found regarding total infectious episodes (OR 0.40, 95% CI 0.28 to 0.58; P < 0.00001).

Conclusions

Flow-directed haemodynamic therapy designed to optimise oxygen delivery protects surgical patients against postoperative hospital-acquired infections and must be strongly encouraged, particularly in the high-risk surgical population.

Influence of the site of measurement on the ability of plethysmographic variability index to predict fluid responsiveness

BACKGROUND

Plethysmographic variability index (PVI) is an accurate predictor of fluid responsiveness in mechanically ventilated patients. However, the site of measurement of the plethysmographic waveform impacts its morphology and its respiratory variation. The goal of this study was to investigate the ability of PVI to predict fluid responsiveness at three sites of measurement (the forehead, ear, and finger) in mechanically ventilated patients under general anaesthesia.

METHODS

We studied 28 subjects after induction of general anaesthesia. Subjects were monitored with a pulmonary artery catheter and three pulse oximeter sensors (the finger, ear, and forehead). Pulse pressure variation, central venous pressure, cardiac index (CI), and PVI measured at the forehead, ear, and finger (PVI(forehead), PVI(ear), and PVI(finger)) were recorded before and after fluid loading (FL). Subjects were responders to volume expansion if CI increased >15% after FL.

RESULTS

Areas under the receiver-operating curves to predict fluid responsiveness were 0.906, 0.880, and 0.836 for PVI(forehead), PVI(ear), and PVI(finger), respectively (P<0.05). PVI(forehead), PVI(ear), and PVI(finger) had a threshold value to predict fluid responsiveness of 15%, 16%, and 12% with sensitivities of 89%, 74%, and 74% and specificities of 78%, 74%, and 67%, respectively.

CONCLUSIONS

PVI can predict fluid responsiveness in anaesthetized and ventilated subjects at all three sites of measurement. However, the threshold values for predicting fluid responsiveness differ with the site of measurement. These results support the use of this plethysmographic dynamic index in the cephalic region when the finger is inaccessible or during states of low peripheral perfusion.

The ability of pulse pressure variations obtained with CNAP™ device to predict fluid responsiveness in the operating room

BACKGROUND

Respiratory-induced pulse pressure variations obtained with an arterial line (ΔPP(ART)) indicate fluid responsiveness in mechanically ventilated patients. The Infinity® CNAP™ SmartPod® (Dräger Medical AG & Co. KG, Lübeck, Germany) provides noninvasive continuous beat-to-beat arterial blood pressure measurements and a near real-time pressure waveform. We hypothesized that respiratory-induced pulse pressure variations obtained with the CNAP system (ΔPP(CNAP)) predict fluid responsiveness as well as ΔPP(ART) predicts fluid responsiveness in mechanically ventilated patients during general anesthesia.

METHODS

Thirty-five patients undergoing vascular surgery were studied after induction of general anesthesia. Stroke volume (SV) measured with the Vigileo™/FloTrac™ (Edwards Lifesciences, Irvine, CA), ΔPP(ART), and ΔPP(CNAP) were recorded before and after intravascular volume expansion (VE) (500 mL of 6% hydroxyethyl starch 130/0.4). Subjects were defined as responders if SV increased by ≥15% after VE.

RESULTS

Twenty patients responded to VE and 15 did not. The correlation coefficient between ΔPP(ART) and ΔPP(CNAP) before VE was r = 0.90 (95% confidence interval [CI] = 0.84-0.96; P < 0.0001). Before VE, ΔPP(ART) and ΔPP(CNAP) were significantly higher in responders than in nonresponders (P < 0.0001). The values of ΔPP(ART) and ΔPP(CNAP) before VE were significantly correlated with the percent increase in SV induced by VE (respectively, r(2) = 0.50; P < 0.0001 and r(2) = 0.57; P < 0.0001). Before VE, a ΔPP(ART) >10% discriminated between responders and nonresponders with a sensitivity of 90% (95% CI = 69%-99%) and a specificity of 87% (95% CI = 60%-98%). The area under the receiver operating characteristic (ROC) curve was 0.957 ± 0.035 for ΔPP(ART). Before VE, a ΔPP(CNAP) >11% discriminated between responders and nonresponders with a sensitivity of 85% (95% CI = 62%-97%) and a specificity of 100% (95% CI = 78%-100%). The area under the ROC curve was 0.942 ± 0.040 for ΔPP(CNAP). There was no significant difference between the area under the ROC curve for ΔPP(ART) and ΔPP(CNAP).

CONCLUSIONS

A value of ΔPP(CNAP) >11% has a sensitivity of at least 62% in predicting preload-dependent responders to VE in mechanically ventilated patients during general anesthesia.

Peri-operative hemodynamic therapy: only large clinical trials can resolve our uncertainty

In this issue of Critical Care, Cecconi and colleagues report the findings of a small trial of goal-directed hemodynamic therapy (GDT) in patients undergoing major orthopedic surgery under regional anesthesia. This is an interesting trial and the first of which we are aware to test the efficacy of GDT in this patient group. The findings suggest that this intervention is associated with improved adverse event rates after surgery. However, in this trial, as in all small trials of GDT, the potential for bias leaves some uncertainty regarding how widely the findings should be implemented. Such limitations may be impossible to completely eliminate from trials of complex interventions, but large multicenter trials may allow us to substantially decrease bias and improve the generalizability of the findings.

Goal-directed haemodynamic therapy during elective total hip arthroplasty under regional anaesthesia

Introduction

Total hip replacement is one of the most commonly performed major orthopaedic operations. Goal-directed therapy (GDT) using haemodynamic monitoring has previously demonstrated outcome benefits in high-risk surgical patients under general anaesthesia. GDT has never been formally assessed during regional anaesthesia.

Methods

Patients undergoing total hip replacement while under regional anaesthesia were randomised to either the control group (CTRL) or the protocol group (GDT). Patients in the GDT group, in addition to standard monitoring, were connected to the FloTrac sensor/Vigileo monitor haemodynamic monitoring system, and a GDT protocol was used to maximise the stroke volume and target the oxygen delivery index to > 600 mL/minute/m².

Results

Patients randomised to the GDT group were given a greater volume of intravenous fluids during the intraoperative period (means ± standard deviation (SD): 6,032 ± 1,388 mL vs. 2,635 ± 346 mL; P < 0.0001), and more of the GDT patients received dobutamine (0 of 20 CTRL patients vs. 11 of 20 GDT patients; P < 0.0003). The GDT patients also received more blood transfused during the intraoperative period (means ± SD: 595 ± 316 mL vs. 0 ± 0 mL; P < 0.0001), although the CTRL group received greater volumes of blood replacement postoperatively (CTRL patients 658 ± 68 mL vs. GDT patients 198 ± 292 mL; P < 0.001). Overall blood consumption (intraoperatively and postoperatively) was not different between the two groups. There were an increased number of complications in the CTRL group (20 of 20 CTRL patients (100%) vs. 16 of 20 GDT patients (80%); P = 0.05). These outcomes were predominantly due to a difference in minor complications (20 of 20 CTRL patients (100%) vs. 15 of 20 GDT patients (75%); P = 0.047).

Conclusions

GDT applied during regional anaesthesia in patients undergoing elective total hip replacement changes intraoperative fluid management and may improve patient outcomes by decreasing postoperative complications. Larger trials are required to confirm our findings.

Trial registration

SRCTN11616985

Randomized clinical trial of epidural, spinal or patient-controlled analgesia for patients undergoing laparoscopic colorectal surgery

BACKGROUND

Epidural analgesia is considered fundamental in enhanced recovery protocols (ERPs). However, its value in laparoscopic colorectal surgery is unclear. The aim of this study was to examine the effects of different analgesic regimens on outcomes following laparoscopic colorectal surgery in fluid-optimized patients treated within an ERP.

METHODS

Ninety-nine patients were randomized to receive epidural, spinal or patient-controlled (PCA) analgesia. The primary endpoints were time until medically fit for discharge and length of hospital stay. Secondary endpoints included return of bowel function, pain scores, and changes in pulmonary function and quality of life.

RESULTS

Ninety-one patients completed the study. The median length of hospital stay was 3.7 days following epidural analgesia, significantly longer than that of 2.7 and 2.8 days for spinal analgesia and PCA respectively (P = 0.002 and P < 0.001). There was also a slower return of bowel function with epidural analgesia than with spinal analgesia and PCA. Epidural analgesia did not offer better preservation of pulmonary function or quality of life, although pain scores were higher in the PCA group in the early postoperative period.

CONCLUSION

Many of the outcomes in the epidural analgesia group were significantly worse than those in the spinal analgesia and PCA groups, suggesting that either of these two modalities could replace epidural analgesia.

Perioperative haemodynamic therapy

PURPOSE OF REVIEW

To discuss the perioperative monitoring tools and targets for haemodynamic optimization and to assess the influence of goal-directed therapy (GDT) on organ function, complications and outcome in different categories of surgical patients.

RECENT FINDINGS

The choice of perioperative haemodynamic monitoring for GDT depends on the surgery-related and the patient-related risk. Conventional monitoring and minimally invasive approaches can be used for perioperative optimization of low-risk to moderate-risk patients. Thermodilution methods and continuous cardiac output/oxygen transport monitoring are the most reliable techniques for major surgery and high-risk/unstable patients. An important goal of perioperative haemodynamic therapy is to maintain cardiac function and organ perfusion, optimizing the balance between oxygen delivery and consumption. Several studies, using different monitoring tools and end-points, have shown that GDT provides optimal haemodynamic performance, improves organ function, reduces the number of complications and time to ICU and hospital discharge and decreases the mortality rate in high-risk surgical patients.

SUMMARY

GDT provides a number of benefits in major surgery. Based on adequate monitoring, the goal-directed algorithms facilitate early detection of pathophysiological changes and influence the perioperative haemodynamic therapy that can improve the clinical outcome. The perioperative GDT should be early, adequate and individualized for every patient.

Peripheral venous pressure as an alternative to central venous pressure in patients undergoing laparoscopic colorectal surgery

BACKGROUND

Peripheral venous pressure (PVP) is strongly correlated with central venous pressure (CVP) during various surgeries. Laparoscopic surgery in the Trendelenburg position with pneumoperitoneum typically increases CVP. To determine whether PVP convincingly reflects changes in CVP, we evaluated the correlation between PVP and CVP in patients undergoing laparoscopic colorectal surgery.

METHODS

Both CVP and PVP were measured simultaneously at predetermined time intervals during elective laparoscopic colorectal surgery in 42 patients without cardiac disease. The pairs of venous pressure measurements were analysed for correlation, and the Bland-Altman plots of repeated measures were used to evaluate the agreement between CVP and PVP.

RESULTS

A total of 420 data pairs were obtained. The overall mean CVP was 11.3 (sd 4.5) mm Hg, which was significantly lower than the measured PVP of mean 12.1 (4.5) mm Hg (P=0.005). There was a strong positive correlation between overall CVP and PVP (correlation coefficient=0.96, P<0.0001). The mean bias (PVP-CVP) corrected for repeated measurements using random-effects modelling was 0.9 mm Hg [95% confidence interval (CI) 0.54-1.19 mm Hg] with 95% limits of agreement of -1.2 mm Hg (95% CI -1.75 to -0.62 mm Hg) to 2.9 mm Hg (95% CI 2.35-3.48 mm Hg).

CONCLUSIONS

PVP displays a strong correlation and agreement with CVP under the increased intrathoracic pressure of pneumoperitoneum in the Trendelenburg position and may be used as an alternative to CVP in patients without cardiac disease undergoing laparoscopic colorectal surgery.

Oesophageal Doppler-guided fluid administration in colorectal surgery: critical appraisal of published clinical trials

The evidence underpinning oesophageal Doppler monitoring (ODM)-guided fluid administration in colorectal surgery has not been critically appraised despite quantitative meta-analyses. A qualitative systematic review of the methodology and findings of all published randomised-controlled trials (RCTs) exploring ODM-guided fluid administration in major abdominal surgery was conducted. Four, well-designed single-centre trials inclusive of 393 patients in total have primarily demonstrated that ODM-guided intraoperative fluid administration decreases hospital length of stay (LOS) and complications by optimising intraoperative cardiac parameters. One subsequently published RCT shows that ODM-guided fluid administration predisposes to a greater LOS and significantly increased complications. However, all the trials have been hampered by imprecise definitions with heterogeneity in patient selection, intraoperative fluid administration strategies and methods of outcome assessment. ODM-guided fluid administration has only been investigated in the setting of laparoscopic colonic surgery and within an optimised perioperative care protocol in one trial, where it was not shown to be beneficial. Nevertheless, it was recommended for use in this context before the trial was even published. ODM-guided fluid administration has not been compared with intraoperative fluid restriction. Current evidence regarding the use of Doppler-guided fluid administration is limited by heterogeneity in the trial design, and the initial clinical benefits observed may be largely offset by recent advances in surgical techniques and perioperative care.

[Perioperative fluid therapy]

Physiologic balance between fluids and electrolytes should remain stable during the perioperative period. Gaps in our understanding of how this balance is maintained has given rise to inappropriate management practices. Both failure to replace lost fluids and the infusion of excessive amounts can lead to serious consequences for the patient. There is currently renewed interest in studying the best use of fluids and/or blood products during and after surgery. This update of perioperative fluid therapy is based on a review of indexed literature retrieved by means of a PubMed search for the period of January 1999 through December 2009.

Maintaining tissue perfusion in high-risk surgical patients: a systematic review of randomized clinical trials

BACKGROUND

Surgical patients with limited organic reserve are considered high-risk patients and have an increased perioperative mortality. For this reason, they need a more rigorous perioperative protocol of hemodynamic control to prevent tissue hypoperfusion. In this study, we systematically reviewed the randomized controlled clinical trials that used a hemodynamic protocol to maintain adequate tissue perfusion in the high-risk surgical patient.

METHODS

We searched MEDLINE, Embase, LILACS, and Cochrane databases to identify randomized controlled clinical studies of surgical patients studied using a perioperative hemodynamic protocol of tissue perfusion aiming to reduce mortality and morbidity; the latter characterized at least one dysfunctional organ in the postoperative period. Pooled odds ratio (POR) and 95% confidence interval (CI) were calculated for categorical outcomes.

RESULTS

Thirty-two clinical trials were selected, comprising 5056 high-risk surgical patients. Global meta-analysis showed a significant reduction in mortality rate (POR: 0.67; 95% CI: 0.55-0.82; P < 0.001) and in postoperative organ dysfunction incidence (POR: 0.62; 95% CI: 0.55-0.70; P < 0.00,001) when a hemodynamic protocol was used to maintain tissue perfusion. When the mortality rate was >20% in the control group, the use of a hemodynamic protocol to maintain tissue optimization resulted in a further reduction in mortality (POR: 0.32; 95% CI: 0.21-0.47; P < 0.00,001). Monitoring cardiac output with a pulmonary artery catheter and increasing oxygen transport and/or decreasing consumption also significantly reduced mortality (POR: 0.67; 95% CI: 0.54-0.84; P < 0.001 and POR: 0.71; 95% CI: 0.57-0.88; P < 0.05, respectively). Therapy directed at increasing mixed or central venous oxygen saturation did not significantly reduce mortality (POR: 0.68; 95% CI: 0.22-2.10; P > 0.05). The only study using lactate as a marker of tissue perfusion failed to demonstrate a statistically significant reduction in mortality (OR: 0.33; 95% CI: 0.07-1.65; P > 0.05).

CONCLUSIONS

In high-risk surgical patients, the use of a hemodynamic protocol to maintain tissue perfusion decreased mortality and postoperative organ failure. Monitoring cardiac output calculating oxygen transport and consumption helped to guide therapy. Additional randomized controlled clinical studies are necessary to analyze the value of monitoring mixed or central venous oxygen saturation and lactate in high-risk surgical patients.

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

BACKGROUND

Complications from major surgery are undesirable, common, and potentially avoidable. The long-term consequences of short-term surgical complications have recently been recognized to have a profound influence on longevity and quality of life in survivors. In the past 30 years, there have been a number of studies conducted attempting to reduce surgical mortality and morbidity by deliberately and preemptively manipulating perioperative hemodynamics. Early studies had a high control-group mortality rate and were criticized for this as being unrepresentative of current practice and raised opposition to its implementation as routine care. We performed this review to update this body of literature and to examine the effect of changes in current practice and quality of care to see whether the conclusions from previous quantitative analyses of this field remain valid.

METHODS

Randomized clinical trials evaluating the use of preemptive hemodynamic intervention to improve surgical outcome were identified using multiple methods. Electronic databases (MEDLINE, EMBASE, and the Cochrane Controlled Clinical Trials register) were screened for potential trials, reference lists of identified trials were examined, and additional sources were sought from experts and industry representatives. Identified studies that fulfilled the entry criteria were examined in full and subjected to quantifiable analysis, subgroup analysis, and sensitivity analysis where possible.

RESULTS

There were 29 studies identified, 23 of which reported surgical complications. In total, the 29 trials involved 4805 patients with an overall mortality of 7.6%. The use of preemptive hemodynamic intervention significantly reduced mortality (pooled odds ratio [95% confidence interval] of 0.48 [0.33-0.78]; P = 0.0002) and surgical complications (odds ratio 0.43 [0.34-0.53]; P < 0.0001). Subgroup analysis showed significant reductions in mortality for studies using a pulmonary artery catheter, supranormal resuscitation targets, studies using cardiac index or oxygen delivery as goals, and the use of fluids and inotropes as opposed to fluids alone. By contrast, there was a significant reduction in morbidity for each of the 4 subgroups analyzed.

CONCLUSION

The use of a preemptive strategy of hemodynamic monitoring and coupled therapy reduces surgical mortality and morbidity.

Using oxygen delivery targets to optimize resuscitation in critically ill patients

PURPOSE OF REVIEW

The use of fluid and inotropic therapies to optimize global haemodynamic variables, in particular oxygen delivery, in critically ill patients has been a controversial area of research for more than 25 years. The aim of this review is to describe the current evidence base for this treatment and how concepts of haemodynamic optimization have evolved in recent years.

RECENT FINDINGS

The inconsistent findings of a large number of small phase II trials continue to stimulate the debate about the value of this treatment approach. However, important recent developments include the use of optimization only during periods of resuscitation, more cautious doses of fluid and/or inotropic therapy, confirmation that pulmonary artery catheter use does not result in excess mortality and an improved understanding of the mechanistic effects of haemodynamic optimization.

SUMMARY

These advances in our understanding have now informed the design of large randomized trials in various patient groups. The true value of haemodynamic optimization is likely to be confirmed or refuted within the next 5 years.

Noninvasive monitoring cardiac output using partial CO(2) rebreathing

This article reviews use of partial carbon dioxide rebreathing devices to determine cardiac output and their application for hemodynamic monitoring in the ICU and operating room. The primary focus is on the NICO monitoring device. Compared with conventional cardiac output methods, these techniques are noninvasive, easily automated, and provide real-time and continuous cardiac output monitoring. The advantages and limitations of each technique are different discussed.

Intraoperative fluid optimization using stroke volume variation in high risk surgical patients: results of prospective randomized study

Introduction

Stroke volume variation (SVV) is a good and easily obtainable predictor of fluid responsiveness, which can be used to guide fluid therapy in mechanically ventilated patients. During major abdominal surgery, inappropriate fluid management may result in occult organ hypoperfusion or fluid overload in patients with compromised cardiovascular reserves and thus increase postoperative morbidity. The aim of our study was to evaluate the influence of SVV guided fluid optimization on organ functions and postoperative morbidity in high risk patients undergoing major abdominal surgery.

Methods

Patients undergoing elective intraabdominal surgery were randomly assigned to a Control group (n = 60) with routine intraoperative care and a Vigileo group (n = 60), where fluid management was guided by SVV (Vigileo/FloTrac system). The aim was to maintain the SVV below 10% using colloid boluses of 3 ml/kg. The laboratory parameters of organ hypoperfusion in perioperative period, the number of infectious and organ complications on day 30 after the operation, and the hospital and ICU length of stay and mortality were evaluated. The local ethics committee approved the study.

Results

The patients in the Vigileo group received more colloid (1425 ml [1000-1500] vs. 1000 ml [540-1250]; P = 0.0028) intraoperatively and a lower number of hypotensive events were observed (2[1-2] Vigileo vs. 3.5[2-6] in Control; P = 0.0001). Lactate levels at the end of surgery were lower in Vigileo (1.78 ± 0.83 mmol/l vs. 2.25 ± 1.12 mmol/l; P = 0.0252). Fewer Vigileo patients developed complications (18 (30%) vs. 35 (58.3%) patients; P = 0.0033) and the overall number of complications was also reduced (34 vs. 77 complications in Vigileo and Control respectively; P = 0.0066). A difference in hospital length of stay was found only in per protocol analysis of patients receiving optimization (9 [8-12] vs. 10 [8-19] days; P = 0.0421). No difference in mortality (1 (1.7%) vs. 2 (3.3%); P = 1.0) and ICU length of stay (3 [2-5] vs. 3 [0.5-5]; P = 0.789) was found.

Conclusions

In this study, fluid optimization guided by SVV during major abdominal surgery is associated with better intraoperative hemodynamic stability, decrease in serum lactate at the end of surgery and lower incidence of postoperative organ complications.

Trial registration

Current Controlled Trials ISRCTN95085011.