Continuous central venous oxygen saturation assisted intraoperative hemodynamic management during major abdominal surgery: a randomized, controlled trial

The relationship between perioperative central venous oxygen saturation and postoperative complications in highly invasive gastroenterological surgery

Purpose

Operations for malignant diseases of the bile duct, pancreas, and esophagus are the most invasive gastroenterological surgeries. The frequency of complications after these surgeries is high, which affects the postoperative course and mortality. In patients who undergo these types of surgeries, continuous monitoring of the perioperative central venous oxygen saturation (ScvO2) is possible via a central venous catheter. We aimed to investigate the relationship between continuously monitored perioperative ScvO2 values and postoperative complications.

Methods

The medical records of 115 patients who underwent highly invasive gastroenterological surgeries and ScvO2 monitoring from April 2012 to March 2014 were analyzed. Sixty patients met the inclusion criteria, and their ScvO2 levels were continuously monitored perioperatively. The relationship between ScvO2 levels and major postoperative complications, defined as Clavien-Dindo grade ≥ III, was examined using uni- and multivariate analysis.

Results

Thirty patients developed major postoperative complications. The adequate cut-off value derived from receiver operating curves of the postoperative average ScvO2 levels for predicting major complications was 75%. Multivariate analysis revealed that low average postoperative ScvO2 levels (p = 0.016) and blood loss ≥ 1000 mL (p = 0.039) were significant predictors of major postoperative complications.

Conclusions

Low perioperative ScvO2 values were associated with an increased risk of major postoperative complications. Continuous ScvO2 monitoring will help prevent postoperative complications.

Restricted Versus Liberal Versus Goal-Directed Fluid Therapy for Non-vascular Abdominal Surgery: A Network Meta-Analysis and Systematic Review

Optimal perioperative fluid management is crucial, with over- or under-replacement associated with complications. There are many strategies for fluid therapy, including liberal fluid therapy (LFT), restrictive fluid therapy (RFT) and goal-directed fluid therapy (GDT), without a clear consensus as to which is better. We aimed to find out which is the more effective fluid therapy option in adult surgical patients undergoing non-vascular abdominal surgery in the perioperative period. This study is a systematic review and network meta-analysis (NMA) with node-splitting analysis of inconsistency, sensitivity analysis and meta-regression. We conducted a literature search of Pubmed, Cochrane Library, EMBASE, Google Scholar and Web of Science. Only studies comparing restrictive, liberal and goal-directed fluid therapy during the perioperative phase in major non-cardiac surgery in adult patients will be included. Trials on paediatric patients, obstetric patients and cardiac surgery were excluded. Trials that focused on goal-directed therapy monitoring with pulmonary artery catheters and venous oxygen saturation (SvO2), as well as those examining purely biochemical and laboratory end points, were excluded. A total of 102 randomised controlled trials (RCTs) and 78 studies (12,100 patients) were included. NMA concluded that goal-directed fluid therapy utilising FloTrac was the most effective intervention in reducing the length of stay (LOS) (surface under cumulative ranking curve (SUCRA) = 91%, odds ratio (OR) = -2.4, 95% credible intervals (CrI) = -3.9 to -0.85) and wound complications (SUCRA = 86%, OR = 0.41, 95% CrI = 0.24 to 0.69). Goal-directed fluid therapy utilising pulse pressure variation was the most effective in reducing the complication rate (SUCRA = 80%, OR = 0.25, 95% CrI = 0.047 to 1.2), renal complications (SUCRA = 93%, OR = 0.23, 95% CrI = 0.045 to 1.0), respiratory complications (SUCRA = 74%, OR = 0.42, 95% CrI = 0.053 to 3.6) and cardiac complications (SUCRA = 97%, OR = 0.067, 95% CrI = 0.0058 to 0.57). Liberal fluid therapy was the most effective in reducing the mortality rate (SUCRA = 81%, OR = 0.40, 95% CrI = 0.12 to 1.5). Goal-directed therapy utilising oesophageal Doppler was the most effective in reducing anastomotic leak (SUCRA = 79%, OR = 0.45, 95% CrI = 0.12 to 1.5). There was no publication bias, but moderate to substantial heterogeneity was found in all networks. In preventing different complications, except mortality, goal-directed fluid therapy was consistently more highly ranked and effective than standard (SFT), liberal or restricted fluid therapy. The evidence grade was low quality to very low quality for all the results, except those for wound complications and anastomotic leak.

Perioperative goal-directed therapy and postoperative complications in different kind of surgical procedures: an updated meta-analysis

BACKGROUND

Goal-directed therapy (GDT) aims to assure tissue perfusion, by optimizing doses and timing of fluids, inotropes, and vasopressors, through monitoring of cardiac output and other basic hemodynamic parameters. Several meta-analyses confirm that GDT can reduce postoperative complications. However, all recent evidences focused on high-risk patients and on major abdominal surgery.

OBJECTIVES

The aim of the present meta-analysis is to investigate the effect of GDT on postoperative complications (defined as number of patients with a least one postoperative complication) in different kind of surgical procedures.

DATA SOURCES

Randomized controlled trials (RCTs) on perioperative GDT in adult surgical patients were included. The primary outcome measure was complications, defined as number of patients with at least one postoperative complication. A subgroup-analysis was performed considering the kind of surgery: major abdominal (including also major vascular), only vascular, only orthopedic surgery. and so on.

STUDY APPRAISAL AND SYNTHESIS METHODS

Meta-analytic techniques (analysis software RevMan, version 5.3.5, Cochrane Collaboration, Oxford, England, UK) were used to combine studies using odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

In 52 RCTs, 6325 patients were enrolled. Of these, 3162 were randomized to perioperative GDT and 3153 were randomized to control. In the overall population, 2836 patients developed at least one complication: 1278 (40%) were randomized to perioperative GDT, and 1558 (49%) were randomized to control. Pooled OR was 0.60 and 95% CI was 0.49-0.72. The sensitivity analysis confirmed the main result. The analysis enrolling major abdominal patients showed a significant result (OR 0.72, 95% CI 0.59-0.87, p = 0.0007, 31 RCTs, 4203 patients), both in high- and low-risk patients. A significant effect was observed in those RCTs enrolling exclusively orthopedic procedures (OR 0.53, 95% CI 0.35-0.80, p = 0.002, 7 RCTs, 650 patients. Also neurosurgical procedures seemed to benefit from GDT (OR 0.40, 95% CI 0.21-0.78, p = 0.008, 2 RCTs, 208 patients). In both major abdominal and orthopedic surgery, a strategy adopting fluids and inotropes yielded significant results. The total volume of fluid was not significantly different between the GDT and the control group.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The present meta-analysis, within the limits of the existing data, the clinical and statistical heterogeneity, suggests that GDT can reduce postoperative complication rate. Moreover, the beneficial effect of GDT on postoperative morbidity is significant on major abdominal, orthopedic and neurosurgical procedures. Several well-designed RCTs are needed to further explore the effect of GDT in different kind of surgeries.

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

Contemporary hemodynamic monitoring, fluid responsiveness, volume optimization, and endpoints of resuscitation: an AAST critical care committee clinical consensus

This article, on hemodynamic monitoring, fluid responsiveness, volume assessment, and endpoints of resuscitation, is part of a compendium of guidelines provided by the AAST (American Association for the Surgery of Trauma) critical care committee. The intention of these guidelines is to inform practitioners with practical clinical guidance. To do this effectively and contemporarily, expert consensus via the critical care committee was obtained. Strict guideline methodology such a GRADE (Grading of Recommendations Assessment, Development and Evaluation) was purposefully NOT used so as not to limit the possible clinical guidance. The critical care committee foresees this methodology as practically valuable to the bedside clinician.

High positive end expiratory pressure levels affect hemodynamics in elderly patients with hypertension admitted to the intensive care unit: a prospective cohort study

Background

To study the effects of different positive end expiratory pressure (PEEP) on blood pressure and heart function in elderly patients with hypertension.

Methods

Forty elderly patients above 65 years of age treated with mechanical ventilation were divided into two groups: a control group of non-hypertensive subjects (n = 18) and a hypertension group (n = 22) patients with essential hypertension. Changes in blood pressure, central venous pressure (CVP), central venous oxygen saturation (ScvO₂), heart rate, and airway pressure were determined in response to different selected PEEP levels of 0, 2, 4, 6, 8, 10 and 12 cm H₂O under SIMV(PC) + PSV mode throughout the study.

Results

In both groups, the increase in PEEP led to an increase in CVP and airway pressure. When PEEP was above 4 cm H₂O in the hypertension group, a decrease in blood pressure and ScvO₂, and an increase of heart rate were observed. These results indicated that cardiac output significantly decreased.

Conclusion

High levels of PEEP can significantly influence changes in blood pressure and heart function in elderly patients with hypertension.

Trial registration

This trial was retrospectively registered, The Chinese trial registration number is ChiCTR-ROC-17012873. The date of registration is 10-2-2017.

Does goal-directed haemodynamic and fluid therapy improve peri-operative outcomes?: A systematic review and meta-analysis

BACKGROUND

Much uncertainty exists as to whether peri-operative goal-directed therapy is of benefit.

OBJECTIVES

To discover if peri-operative goal-directed therapy decreases mortality and morbidity in adult surgical patients.

DESIGN

An updated systematic review and random effects meta-analysis of randomised controlled trials.

DATA SOURCES

Medline, Embase and the Cochrane Library were searched up to 31 December 2016.

ELIGIBILITY CRITERIA

Randomised controlled trials enrolling adult surgical patients allocated to receive goal-directed therapy or standard care were eligible for inclusion. Trauma patients and parturients were excluded. Goal-directed therapy was defined as fluid and/or vasopressor therapy titrated to haemodynamic goals [e.g. cardiac output (CO)]. Outcomes included mortality, morbidity and hospital length of stay. Risk of bias was assessed using Cochrane methodology.

RESULTS

Ninety-five randomised trials (11 659 patients) were included. Only four studies were at low risk of bias. Modern goal-directed therapy reduced mortality compared with standard care [odds ratio (OR) 0.66; 95% confidence interval (CI) 0.50 to 0.87; number needed to treat = 59; N = 52; I = 0.0%]. In subgroup analysis, there was no mortality benefit for fluid-only goal-directed therapy, cardiac surgery patients or nonelective surgery. Contemporary goal-directed therapy also reduced pneumonia (OR 0.69; 95% CI, 0.51 to 0. 92; number needed to treat = 38), acute kidney injury (OR 0. 73; 95% CI, 0.58 to 0.92; number needed to treat = 29), wound infection (OR 0.48; 95% CI, 0.37 to 0.63; number needed to treat = 19) and hospital length of stay (days) (-0.90; 95% CI, -1.32 to -0.48; I = 81. 2%). No important differences in outcomes were found for the pulmonary artery catheter studies, after accounting for advances in the standard of care.

CONCLUSION

Peri-operative modern goal-directed therapy reduces morbidity and mortality. Importantly, the quality of evidence was low to very low (e.g. Grading of Recommendations, Assessment, Development and Evaluation scoring), and there was much clinical heterogeneity among the goal-directed therapy devices and protocols. Additional well designed and adequately powered trials on peri-operative goal-directed therapy are necessary.

Hemodynamic goal-directed therapy and postoperative kidney injury: an updated meta-analysis with trial sequential analysis

Background

Perioperative goal-directed therapy (GDT) reduces the risk of renal injury. However, several questions remain unanswered, such as target, kind of patients and surgery, and role of fluids and inotropes. We therefore update a previous analysis, including all studies published in the meanwhile, to clarify the clinical impact of this strategy on acute kidney injury.

Main body

Randomized controlled trials enrolling adult patients undergoing major surgery were considered. GDT was defined as perioperative monitoring and manipulation of hemodynamic parameters to reach normal or supranormal values by fluids alone or with inotropes. Trials comparing the effects of GDT and standard hemodynamic therapy were considered. Primary outcome was acute kidney injury, whichever definition was used. Meta-analytic techniques (analysis software RevMan, version 5.3) were used to combine studies, using random-effect odds ratios (OR) and 95% confidence intervals (CI). Trial sequential analyses were performed including all trials and considering only low risk of bias trials. Sixty-five trials with an overall sample of 9308 patients were included. OR for the development of renal injury was 0.64 (95% CI, 0.62–0.87; p = 0.0003), with no statistical heterogeneity. Trial sequential analyses and sensitivity analysis including studies with low risk of bias confirmed the main results. A significant decrease in renal injury rate was observed in studies that adopted cardiac output and oxygen delivery as hemodynamic target and that used both fluids and inotropes. The postoperative kidney injury rate was significantly lower in trials enrolling “high-risk” patients and major abdominal and orthopedic surgery.

Short conclusion

The present meta-analysis suggests that targeting GDT to perioperative systemic oxygen delivery, by means of fluids and inotropes, can be the best way to improve renal perfusion and oxygenation in high-risk patients undergoing major abdominal and orthopedic surgery.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2516-4) contains supplementary material, which is available to authorized users.

Enhanced recovery after surgery protocol enhances early postoperative recovery after pancreaticoduodenectomy

BACKGROUND

Enhanced recovery after surgery (ERAS) protocol is a multimodal, multidisciplinary and evidence-based approach to reduce surgical stress and enhance recovery in the postoperative period. This study aimed to analyze the outcome of ERAS protocol in patients after pancreaticoduodenectomy (PD).

METHODS

A total of 50 consecutive patients with pancreatic/periampullary cancer who underwent PD between January 2016 to August 2017 were included in the study. As per the institute ERAS protocol, nasogastric tube (NGT) was removed on postoperative day (POD) 1 if output was less than 200 mL and oral sips were allowed; oral liquids were allowed on POD2; semisolid diet by POD3; abdominal drain was removed on POD 4 if output was less than 100 mL with no evidence of postoperative pancreatic fistula (POPF); normal diet was allowed on POD5. Discharge criteria on POD6 were afebrile, tolerating oral normal diet, pain free and no surgery related complications (defined as per the ISGPS definitions).

RESULTS

NGT was removed on POD1 in 45 (90%) patients, abdominal drain removed by POD4 in 41 (82%) and 43 (86%) patients were discharged on POD6. There was no 30-day postoperative mortality. Three (6%) patients had delayed gastric emptying (DGE). None had postoperative hemorrhage and POPF. Readmission rate was 8%. A significant relation was found between the length of hospital stay (LOS) with age (P < 0.05) and a marginal relation between LOS and postoperative albumin (P = 0.05).

CONCLUSIONS

ERAS protocol can be safely followed in the perioperative care of patients who undergo PD. Early removal of NGT and allowing oral diet restore bowel function early. ERAS decreases the LOS and postoperative complications.

Effects of time delay and body temperature on measurements of central venous oxygen saturation, venous-arterial blood carbon dioxide partial pressures difference, venous-arterial blood carbon dioxide partial pressures difference/arterial-venous oxygen difference ratio and lactate

BACKGROUND

Central venous oxygen saturation (ScvO₂), venous-arterial blood carbon dioxide partial pressures difference (Pv-aCO₂), venous-arterial blood carbon dioxide partial pressures difference/arterial-venous oxygen difference ratio (Pv-aCO₂/Ca-vO₂) and lactate are important parameters employed during shock resuscitation. We designed this study to confirm the effects of time delay and body temperature on measurements of these four parameters.

METHODS

Arterial and central venous blood samples were simultaneously drawn by plastic syringes via indwelling intra-arterial and central venous catheters from critically ill patients. Blood gas analyses were performed on both samples and repeated after 10, 20, 30, 40, 50 and 60 min. Patients were divided into a control group and a high temperature group according to whether the body temperature was greater than 38 °C.

RESULTS

A total of 30 critically ill patients were enrolled. There was a trend of increasing values for ScvO₂, Pv-aCO₂, Pv-aCO₂/Ca-vO₂ and lactate over time (P < 0.001). The ScvO₂ differences were all lower in high temperature group after 10, 20, 30, 40, 50 and 60 min when compared to the corresponding differences in the control group (P < 0.05). The differences in lactate values were slightly higher in the high temperature group, relative to the control group after 20, 30, 40, 50 and 60 min (P < 0.05).

CONCLUSIONS

Measurements of ScvO₂, Pv-aCO₂, lactate and Pv-aCO₂/Ca-vO₂ were affected by time delay or body temperature. We recommend that arterial and central venous blood gas samples be analyzed quickly within 10 min, especially for patients with body temperature <38 °C.

TRIAL REGISTRATION

ChiCTR, ChiCTR1800014484 . Registered 16 January 2018.

Perioperative goal-directed therapy: A systematic review without meta-analysis

BACKGROUND

Perioperative goal-directed therapy aims to optimise haemodynamics by titrating fluids, vasopressors and/or inotropes to predefined haemodynamic targets. Perioperative goal-directed therapy is a complex intervention composed of several independent component interventions. Trials on perioperative goal-directed therapy show conflicting results. We aimed to conduct a systematic review and meta-analysis to investigate the benefits and harms of perioperative goal-directed therapy.

METHODS

PubMED, EMBASE, Web of Science and Cochrane Library were searched. Trials were included if they had a perioperative goal-directed therapy protocol. The primary outcome was all-cause mortality. The first secondary outcome was serious adverse events excluding mortality. Risk of bias was assessed, and GRADE was used to evaluate quality of evidence.

RESULTS

One hundred and twelve randomised trials were included of which one trial (1%) had low risk of bias. Included trials varied in patients: types of surgery which was expected due to inclusion criteria; in intervention and comparison: timing of intervention, monitoring devices, haemodynamic variables, target values, use of fluids, vasopressors and/or inotropes as well as combinations of these within protocols; and in outcome: mortality was reported in 87 trials (78%). Due to substantial clinical heterogeneity also within the various types of surgery a meta-analysis of data, including subgroup analyses, as defined in our protocol was considered inappropriate.

CONCLUSION

Clinical heterogeneity in patients, interventions and outcomes in perioperative goal-directed therapy trials is too large to perform meta-analysis on all trials. Future trials and meta-analyses highly depend on universally agreed definitions on aspects beyond type of surgery of the complex intervention and its evaluation.

Association of conflicts of interest with the results and conclusions of goal-directed hemodynamic therapy research: a systematic review with meta-analysis

PURPOSE

The association between conflicts of interest (COI) and study results or article conclusions in goal-directed hemodynamic therapy (GDHT) research is unknown.

METHODS

Randomized controlled trials comparing GDHT with usual care were identified. COI were classified as industry sponsorship, author conflict, device loaner, none, or not reported. The association between COI and study results (complications and mortality) was assessed using both stratified meta-analysis and mixed effects meta-regression. The association between COI and an article's conclusion (graded as GDHT-favorable, neutral, or unfavorable) was investigated using logistic regression.

RESULTS

Of the 82 eligible articles, 43 (53%) had self-reported COI, and 50 (61%) favored GDHT. GDHT significantly reduced complications on the basis of the meta-analysis of studies with any type of COI, studies declaring no COI, industry-sponsored studies, and studies with author conflict but not on studies with a device loaner. However, no significant relationship between COI and the relative risk (GDHT vs. usual care) of developing complications was found on the basis of meta-regression (p = 0.25). No significant effect of GDHT was found on mortality. COI had a significant overall effect (p = 0.016) on the odds of having a GDHT-favorable vs. neutral conclusion based on 81 studies. Eighty-four percent of the industry-sponsored studies had a GDHT-favorable conclusion, while only 27% of the studies with a device loaner had the same conclusion grade.

CONCLUSIONS

The available evidence does not suggest a close relationship between COI and study results in GDHT research. However, a potential association may exist between COI and an article's conclusion in GDHT research.

Monitoring of Tissue Oxygenation: an Everyday Clinical Challenge

Purpose of review

The aim of this article is to study the overview of pathophysiology and clinical application of central venous oxygen saturation monitoring in critically ill patients and during the perioperative period.

Recent findings

There are several clinical studies and animal experiments evaluating the effects of goal-directed hemodynamic stabilization on critically ill patients. Recent systematic reviews and meta-analyses found that advanced hemodynamic endpoints-targeted management has a positive effect on outcome in high-risk surgical patients. As all interventions aim to improve tissue oxygenation, it is of utmost importance to monitor the balance between oxygen delivery and consumption. For this purpose, central venous blood gas analysis provides an easily available tool in the everyday clinical practice. The adequate interpretation of central venous oxygen saturation renders the need of careful evaluation of several physiological and pathophysiological circumstances. When appropriately evaluated, central venous oxygen saturation can be a valuable component of a multimodal individualized approach, in which components of oxygen delivery are put in the context of the patients' individual oxygen consumption. In addition to guide therapy, central venous oxygen saturation may also serve as an early warning sign of inadequate oxygen delivery, which would otherwise remain hidden from the attending physician.

Summary

With the incorporation of central venous oxygen saturation in the everyday clinical routine, treatment could be better tailored for the patients' actual needs; hence, it may also improve outcome.

Systematic review of the association of venous oxygenation and outcome in adult hospitalized patients

BACKGROUND

Adequate tissue oxygenation is necessary to maintain organ function. Low venous oxygen saturation may reflect impaired tissue oxygenation, and may be used as a predictive tool and a therapeutic target to improve the care of critically ill patients. We therefore conducted a systematic review of the existing literature reflecting these aspects.

METHODS

We searched electronic databases in January 2016 for relevant studies on venous oxygen saturation for treatment guidance and patient outcome. We sub-grouped results based on patient groups and setting.

RESULTS

The search resulted in 5590 papers of which 42 studies were deemed relevant. The majority of the studies in cardiac and abdominal surgery patients showed associations between low venous oxygen saturation and increased mortality and morbidity, in particular increased length of intensive care. However, the cut-off level for low venous oxygen saturation varied between < 55 and 70% and all studies had high risk of bias. In patients with septic shock, recent randomized trials showed no benefit of early resuscitation guided by venous oxygen saturation.

CONCLUSION

Low venous oxygen saturation may be associated with increased mortality, morbidity and length of intensive care in patients following cardiac or abdominal surgery. However, the wide range of cut-off levels and low quality of evidence hampers the clinical application. In patients with septic shock, the present evidence does not support goal-directed therapy using venous oxygen saturation during early resuscitation.

Detecting central-venous oxygen desaturation without a central-venous catheter: Utility of the difference between invasively and noninvasively measured blood pressure

OBJECTIVE

The objective was to determine whether central-venous oxygen saturation (ScvO2<70%) can be detected from the difference between invasively and noninvasively measured systolic blood pressure (BP) (ie, ΔBP defined as arterial BP minus noninvasive BP).

METHODS

This is a cross-sectional study at a single medical and surgical intensive care unit in Japan. All hypotensive patients admitted to intensive care unit were eligible. Arterial BP was measured via a radial-artery catheter, and noninvasive BP on the same side was measured via a brachial cuff. ScvO2 was measured by gas analysis of blood sampled from a central-venous chatheter (CVC). We calculate the area under the curve for ΔBP as an indicator of ScvO2<70%.

RESULTS

Usable data were obtained from the records of 111 patients. The median and interquartile range of ΔBP and ScvO2 were -4mm Hg (-11, 6) and 67% (60.9, 73.9), respectively. The area under the curve of ΔBP as an indicator of ScvO2<70% was 0.81 (95% confidence interval [CI], 0.73-0.89). With a cutoff ΔBP of 0, sensitivity was 65.7% (95% CI, 53.1-76.8), specificity was 97.7% (95% CI, 88.0-99.8), and positive predictive value was 97.8 (95% CI, 88.2-99.9).

CONCLUSIONS

ΔBP can indicate whether ScvO2 is lower than 70%. When that difference is greater than 0, ScvO2 is very likely to be lower than 70%.

Goal-Directed Resuscitation Aiming Cardiac Index Masks Residual Hypovolemia: An Animal Experiment

The aim of this study was to compare stroke volume (SVI) to cardiac index (CI) guided resuscitation in a bleeding-resuscitation experiment. Twenty six pigs were randomized and bled in both groups till baseline SVI (T_bsl) dropped by 50% (T₀), followed by resuscitation with crystalloid solution until initial SVI or CI was reached (T₄). Similar amount of blood was shed but animals received significantly less fluid in the CI-group as in the SVI-group: median = 900 (interquartile range: 850–1780) versus 1965 (1584–2165) mL, p = 0.02, respectively. In the SVI-group all variables returned to their baseline values, but in the CI-group animals remained underresuscitated as indicated by SVI, heart rate (HR) and stroke volume variation (SVV), and central venous oxygen saturation (S_cvO₂) at T₄ as compared to T_bsl: SVI = 23.8 ± 5.9 versus 31.4 ± 4.7 mL, HR: 117 ± 35 versus 89 ± 11/min SVV: 17.4 ± 7.6 versus 11.5 ± 5.3%, and S_cvO₂: 64.1 ± 11.6 versus 79.2 ± 8.1%, p < 0.05, respectively. Our results indicate that CI-based goal-directed resuscitation may result in residual hypovolaemia, as bleeding caused stress induced tachycardia “normalizes” CI, without restoring adequate SVI. As the SVI-guided approach normalized most hemodynamic variables, we recommend using SVI instead of CI as the primary goal of resuscitation during acute bleeding.