A randomised trial of non-invasive cardiac output monitoring to guide haemodynamic optimisation in high risk patients undergoing urgent surgical repair of proximal femoral fractures (ClearNOF trial NCT02382185)

Intraoperative Hypotension in Patients Having Major Noncardiac Surgery Under General Anesthesia: A Systematic Review of Blood Pressure Optimization Strategies

INTRODUCTION

Intraoperative hypotension is associated with increased risks of postoperative complications. Consequently, a variety of blood pressure optimization strategies have been tested to prevent or promptly treat intraoperative hypotension. We performed a systematic review to summarize randomized controlled trials that evaluated the efficacy of blood pressure optimization interventions in either mitigating exposure to intraoperative hypotension or reducing risks of postoperative complications.

METHODS

Medline, Embase, PubMed, and Cochrane Controlled Register of Trials were searched from database inception to August 2, 2023, for randomized controlled trials (without language restriction) that evaluated the impact of any blood pressure optimization intervention on intraoperative hypotension and/or postoperative outcomes.

RESULTS

The review included 48 studies (N = 46,377), which evaluated 10 classes of blood pressure optimization interventions. Commonly assessed interventions included hemodynamic protocols using arterial waveform analysis, preoperative withholding of antihypertensive medications, continuous blood pressure monitoring, and adjuvant agents (vasopressors, anticholinergics, anticonvulsants). These same interventions reduced intraoperative exposure to hypotension. Conversely, low blood pressure alarms had an inconsistent impact on exposure to hypotension. Aside from limited evidence that higher prespecified intraoperative blood pressure targets led to a reduced risk of complications, there were few data suggesting that these interventions prevented postoperative complications. Heterogeneity in interventions and outcomes precluded meta-analysis.

CONCLUSIONS

Several different blood pressure optimization interventions show promise in reducing exposure to intraoperative hypotension. Nonetheless, the impact of these interventions on clinical outcomes remains unclear. Future trials should assess promising interventions in samples sufficiently large to identify clinically plausible treatment effects on important outcomes.

KEY POINTS

Guidelines on perioperative optimization protocol for the adult patient 2023

OBJECTIVE

The French Society of Anesthesiology and Intensive Care Medicine [Société Française d'Anesthésie et de Réanimation (SFAR)] aimed at providing guidelines for the implementation of perioperative optimization programs.

DESIGN

A consensus committee of 29 experts from the SFAR was convened. A formal conflict-of-interest policy was developed at the outset of the process and enforced throughout. The entire guidelines process was conducted independently of any industry funding. The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence.

METHODS

Four fields were defined: 1) Generalities on perioperative optimization programs; 2) Preoperative measures; 3) Intraoperative measures and; 4) Postoperative measures. For each field, the objective of the recommendations was to answer a number of questions formulated according to the PICO model (population, intervention, comparison, and outcomes). Based on these questions, an extensive bibliographic search was carried out using predefined keywords according to PRISMA guidelines and analyzed using the GRADE® methodology. The recommendations were formulated according to the GRADE® methodology and then voted on by all the experts according to the GRADE grid method. As the GRADE® methodology could have been fully applied for the vast majority of questions, the recommendations were formulated using a "formalized expert recommendations" format.

RESULTS

The experts' work on synthesis and application of the GRADE® method resulted in 30 recommendations. Among the formalized recommendations, 19 were found to have a high level of evidence (GRADE 1±) and ten a low level of evidence (GRADE 2±). For one recommendation, the GRADE methodology could not be fully applied, resulting in an expert opinion. Two questions did not find any response in the literature. After two rounds of rating and several amendments, strong agreement was reached for all the recommendations.

CONCLUSIONS

Strong agreement among the experts was obtained to provide 30 recommendations for the elaboration and/or implementation of perioperative optimization programs in the highest number of surgical fields.

Breaking Down the Evidence: Does Perioperative Hypotension Cause Kidney Injury?

BACKGROUND

Acute kidney injury (AKI) is common in the postoperative period and is associated with negative patient outcomes. The definition of perioperative hypotension is wide, but it is associated with various complications, including AKI.

SUMMARY

Preclinical data suggest that sustained severe renal hypoperfusion per se does not cause persistent AKI. The evidence associating blood pressure levels and postoperative renal dysfunction is predominantly retrospective and observational, and therefore potentially misled by the complex interactions between exposures, confounders, and mediators.

KEY MESSAGES

To better understand how perioperative hemodynamic management could affect the occurrence of kidney injury, it is pivotal to further investigate the association between hypotension and kidney dysfunction in the perioperative period and determine the degree to which hypotension is a causal factor.

Effect of goal-directed haemodynamic therapy guided by non-invasive monitoring on perioperative complications in elderly hip fracture patients within an enhanced recovery pathway

Background

Goal-directed haemodynamic therapy (GDHT) has been shown to reduce morbidity and mortality in high-risk surgical patients. However, there is little evidence of its efficacy in patients undergoing hip fracture surgery. This study aims to evaluate the effect of GDHT guided by non-invasive haemodynamic monitoring on perioperative complications in patients undergoing hip fracture surgery.

Methods

Patients > 64 years undergoing hip fracture surgery within an enhanced recovery pathway (ERP) were enrolled in this single-centre, non-randomized, intervention study with a historical control group and 12-month follow-up. Exclusion criteria were patients with pathological fractures, traffic-related fractures and refractures. Control group (CG) patients received standard care treatment. Intervention group (IG) patients received a GDHT protocol based on achieving an optimal stroke volume, in addition to a systolic blood pressure > 90 mmHg and an individualized cardiac index. No changes were made between groups in the ERP during the study period. Primary outcome was percentage of patients who developed intraoperative haemodynamic instability. Secondary outcomes were intraoperative arrhythmias, postoperative complications (cardiovascular, respiratory, infectious and renal complications), administered fluids, vasopressor requirements, perioperative transfusion, length of hospital stay, readmission and 1-year survival.

Results

In total, 551 patients (CG=272; IG=279) were included. Intraoperative haemodynamic instability was lower in the IG (37.5% vs 28.0%; p=0.017). GDHT patients had fewer postoperative cardiovascular (18.8% vs 7.2%; p < 0.001), respiratory (15.1% vs 3.6%; p<0.001) and infectious complications (21% vs 3.9%; p<0.001) but not renal (12.1% vs 33.7%; p<0.001). IG patients had less vasopressor requirements (25.5% vs 39.7%; p<0.001) and received less fluids [2.600 ml (IQR 1700 to 2700) vs 850 ml (IQR 750 to 1050); p=0.001] than control group. Fewer patients required transfusion in GDHT group (73.5% vs 44.4%; p<0.001). For IG patients, median length of hospital stay was shorter [11 days (IQR 8 to 16) vs 8 days; (IQR 6 to 11) p < 0.001] and 1-year survival higher [73.4% (95%CI 67.7 to 78.3 vs 83.8% (95%CI 78.8 to 87.7) p<0.003].

Conclusions

The use of GDHT decreases intraoperative complications and postoperative cardiovascular, respiratory and infectious but not postoperative renal complications. This strategy was associated with a shorter hospital stay and increased 1-year survival.

Trial registration

ClinicalTrials.gov NCT02479321.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13741-022-00277-w.

Goal-directed haemodynamic therapy during general anaesthesia for noncardiac surgery: a systematic review and meta-analysis

BACKGROUND

During general anaesthesia for noncardiac surgery, there remain knowledge gaps regarding the effect of goal-directed haemodynamic therapy on patient-centred outcomes.

METHODS

Included clinical trials investigated goal-directed haemodynamic therapy during general anaesthesia in adults undergoing noncardiac surgery and reported at least one patient-centred postoperative outcome. PubMed and Embase were searched for relevant articles on March 8, 2021. Two investigators performed abstract screening, full-text review, data extraction, and bias assessment. The primary outcomes were mortality and hospital length of stay, whereas 15 postoperative complications were included based on availability. From a main pool of comparable trials, meta-analyses were performed on trials with homogenous outcome definitions. Certainty of evidence was evaluated using Grading of Recommendations, Assessment, Development, and Evaluations (GRADE).

RESULTS

The main pool consisted of 76 trials with intermediate risk of bias for most outcomes. Overall, goal-directed haemodynamic therapy might reduce mortality (odds ratio=0.84; 95% confidence interval [CI], 0.64 to 1.09) and shorten length of stay (mean difference=-0.72 days; 95% CI, -1.10 to -0.35) but with low certainty in the evidence. For both outcomes, larger effects favouring goal-directed haemodynamic therapy were seen in abdominal surgery, very high-risk surgery, and using targets based on preload variation by the respiratory cycle. However, formal tests for subgroup differences were not statistically significant. Goal-directed haemodynamic therapy decreased risk of several postoperative outcomes, but only infectious outcomes and anastomotic leakage reached moderate certainty of evidence.

CONCLUSIONS

Goal-directed haemodynamic therapy during general anaesthesia might decrease mortality, hospital length of stay, and several postoperative complications. Only infectious postoperative complications and anastomotic leakage reached moderate certainty in the evidence.

Increased risk of hip fracture mortality associated with intraoperative hypotension in elderly hip fracture patients is related to under resuscitation

BACKGROUND

As the US and world population ages, hip fractures are increasingly more common. The mortality associated with these fractures remains high both in the immediate postoperative period and at one year. Perioperative resuscitation in this population is of key interest to prevent organ injury and mortality. Our objectives were to evaluate the effect of fluid resuscitation and hemodynamic status in the form of mean arterial pressure (MAP) on inpatient mortality of hip fracture patients.

METHODS

An institutional database was queried to compare elderly hip fracture patients that sustained in-hospital mortality to a matched control cohort. Pre-, intra-, and post-operative intravenous fluid (IVF) administration and MAP were extracted from the electronic medical record. Time from hospital presentation to the OR was also recorded.

RESULTS

1,114 total hip fractures were identified during the two-year study period, 16 of which suffered inpatient mortalities. The mortality cohort was then matched with a control of 394 hip fracture patients for the same period based on age, sex, and Charlson Comorbidity Index (CCI). Conditional logistical regression analysis found odds ratios (OR) indicating that longer time between presentation and surgery (OR per additional hour: 1.05; 95% CI: 1.01-1.08) and lower intraoperative minimum MAP (OR per 5 mmHg decrease: 0.77; 95% CI: 0.61-0.97) were associated with significantly increased odds of mortality. There was also a marginal relationship between greater intraoperative IVF administration and reduced odds of mortality (OR per 500 cc additional fluid: 0.61; 95% CI: 0.37-1.00).

CONCLUSION

Extended time from presentation to surgery and intraoperative hypotension were associated with increased likelihood of inpatient mortality in an elderly hip fracture cohort, with a possible additional effect of under-resuscitation. Further investigation into a safe intraoperative minimum MAP should be pursued.

LEVEL OF EVIDENCE

Level III.

Effect of strict intraoperative blood pressure management strategy on postoperative acute kidney injury in non-cardiac surgery: A meta-analysis of randomised controlled trials

BACKGROUND

Acute kidney injury (AKI) is one of the most serious perioperative complications. 20% to 40% of high-risk patients who undergo non-cardiac surgery have AKI and those with AKI are eight-times more likely to die within 30 days after surgery. It may be related to intraoperative hypotension, which is mainly caused by vasodilatory and cardiodepressant effects of anaesthesia, and/or hypovolemia. Strict intraoperative blood pressure management strategy (strict BP management) is a potential option to prevent postoperative AKI. This strategy refers to additional administration of vasoactive agents under the premise of a protocolised fluid delivery. The efficacy of strict BP management for preventing postoperative AKI in non-cardiac surgery patients was assessed by a meta-analysis.

METHODS

We systematically retrieved randomised controlled trials (RCTs) and compared strict BP management with conventional therapy control on effect of postoperative AKI in non-cardiac surgery patients, which were published on PubMed, EMBASE, Cochrane library and Web of Science databases before October 5, 2020. Ultimately, a meta-analysis of all RCTs eligible for inclusion criteria was performed.

RESULTS

Five RCTs, comprising 1485 patients, were included in the meta-analysis. Strict BP management was associated with a reduced incidence of postoperative AKI [relative risk (RR) = 0.73, 95% confidence interval (CI): 0.58-0.92, P = .007]. No significant difference was found between strict BP management group and conventional therapy control in mortality at longest follow-up available (RR = 0.92, 95% CI: 0.68-1.25, P = .60). In the subset analysis, the studies using supranormal BP management target was significantly lower in the incidence of postoperative AKI (RR = 0.65, 95% CI: 0.51-0.82, P = .0003) CONCLUSION: Strict BP management is significantly more effective than conventional therapy for the prevention of postoperative AKI. Supranormal target of intraoperative BP management may be considered a more appealing option for the prevention of AKI.

Hypovolemic Status in Older Hip Fracture Patients Elucidated by Preoperative Transthoracic Echocardiography

Older patients undergoing hip fracture surgery often experience intraoperative hemodynamic instability despite maintaining cardiac function. Although preoperative hemodynamics in such patients have been demonstrated mainly through invasive monitoring, few studies have addressed hemodynamics based on noninvasively measured parameters. We aimed to investigate preoperative hemodynamic states in older hip fracture patients using transthoracic echocardiography (TTE). The TTE data of patients aged >75 years who underwent hip fracture surgery or elective total hip arthroplasty (THA) between April 1, 2019, and March 31, 2021, were collected. In addition to the baseline characteristics, the TTE data from hip fracture patients were compared with the data of those who underwent THA. The hip fracture patients (n = 167) were significantly older and had lower stroke volume (45.6 vs. 50.9 ml; p < 0.01) and stroke index (33.7 vs. 36.6 ml/m²; p < 0.01) compared to those who underwent elective THA (n = 44). However, the cardiac output (3.51 vs. 3.48 L/min; p=0.273) and cardiac index (2.6 vs. 2.47 L/min/m²; p=0.855) for both groups were almost identical due to the increase in heart rate in the hip fracture group. Regarding other parameters including ejection fraction, fractional shortening, E/E′, and inferior vena cava diameter, there were no significant differences between the two groups. Our noninvasive TTE investigations suggested that hip fracture patients were volume-depleted, and the hypovolemic status activated the sympathetic nervous system, compensating for their cardiac output. Anesthesiologists must focus on the TTE-assessed parameters reflecting the volume status along with the cardiac function.

Goal-directed haemodynamic therapy (GDHT) in surgical patients: systematic review and meta-analysis of the impact of GDHT on post-operative pulmonary complications

Background

Perioperative goal-directed haemodynamic therapy (GDHT), defined as the administration of fluids with or without inotropes or vasoactive agents against explicit measured goals to augment blood flow, has been evaluated in many randomised controlled trials (RCTs) over the past four decades. Reported post-operative pulmonary complications commonly include chest infection or pneumonia, atelectasis, acute respiratory distress syndrome or acute lung injury, aspiration pneumonitis, pulmonary embolism, and pulmonary oedema. Despite the substantial clinical literature in this area, it remains unclear whether their incidence is reduced by GDHT. This systematic review aims to determine the effect of GDHT on the respiratory outcomes listed above, in surgical patients.

Methods

We searched the Cochrane Central Register for Controlled Trials (CENTRAL), MEDLINE, EMBASE, and clinical trial registries up until January 2020. We included all RCTs reporting pulmonary outcomes. The primary outcome was post-operative pulmonary complications and secondary outcomes were specific pulmonary complications and intra-operative fluid input. Data synthesis was performed on Review Manager and heterogeneity was assessed using I² statistics.

Results

We identified 66 studies with 9548 participants reporting pulmonary complications. GDHT resulted in a significant reduction in total pulmonary complications (OR 0.74, 95% CI 0.59 to 0.92). The incidence of pulmonary infections, reported in 45 studies with 6969 participants, was significantly lower in the GDHT group (OR 0.72, CI 0.60 to 0.86). Pulmonary oedema was recorded in 23 studies with 3205 participants and was less common in the GDHT group (OR 0.47, CI 0.30 to 0.73). There were no differences in the incidences of pulmonary embolism or acute respiratory distress syndrome. Sub-group analyses demonstrated: (i) benefit from GDHT in general/abdominal/mixed and cardiothoracic surgery but not in orthopaedic or vascular surgery; and (ii) benefit from fluids with inotropes and/or vasopressors in combination but not from fluids alone. Overall, the GDHT group received more colloid (+280 ml) and less crystalloid (−375 ml) solutions than the control group. Due to clinical and statistical heterogeneity, we downgraded this evidence to moderate.

Conclusions

This systematic review and meta-analysis suggests that the use of GDHT using fluids with inotropes and/or vasopressors, but not fluids alone, reduces the development of post-operative pulmonary infections and pulmonary oedema in general, abdominal and cardiothoracic surgical patients. This evidence was graded as moderate.

PROSPERO registry reference: CRD42020170361

Hydroxyethyl starch for perioperative goal-directed fluid therapy in 2020: a narrative review

BACKGROUND

Perioperative fluid management - including the type, dose, and timing of administration -directly affects patient outcome after major surgery. The objective of fluid administration is to optimize intravascular fluid status to maintain adequate tissue perfusion. There is continuing controversy around the perioperative use of crystalloid versus colloid fluids. Unfortunately, the importance of fluid volume, which significantly influences the benefit-to-risk ratio of each chosen solution, has often been overlooked in this debate.

MAIN TEXT

The volume of fluid administered during the perioperative period can influence the incidence and severity of postoperative complications. Regrettably, there is still huge variability in fluid administration practices, both intra-and inter-individual, among clinicians. Goal-directed fluid therapy (GDFT), aimed at optimizing flow-related variables, has been demonstrated to have some clinical benefit and has been recommended by multiple professional societies. However, this approach has failed to achieve widespread adoption. A closed-loop fluid administration system designed to assist anesthesia providers in consistently applying GDFT strategies has recently been developed and tested. Such an approach may change the crystalloid versus colloid debate. Because colloid solutions have a more profound effect on intravascular volume and longer plasma persistence, their use in this more "controlled" context could be associated with a lower fluid balance, and potentially improved patient outcome. Additionally, most studies that have assessed the impact of a GDFT strategy on the outcome of high-risk surgical patients have used hydroxyethyl starch (HES) solutions in their protocols. Some of these studies have demonstrated beneficial effects, while none of them has reported severe complications.

CONCLUSIONS

The type and volume of fluid used for perioperative management need to be individualized according to the patient's hemodynamic status and clinical condition. The amount of fluid given should be guided by well-defined physiologic targets. Compliance with a predefined hemodynamic protocol may be optimized by using a computerized system. The type of fluid should also be individualized, as should any drug therapy, with careful consideration of timing and dose. It is our perspective that HES solutions remain a valid option for fluid therapy in the perioperative context because of their effects on blood volume and their reasonable benefit/risk profile.