AO Spine/Praxis Clinical Practice Guidelines for the Management of Acute Spinal Cord Injury: An Introduction to a Focus Issue

STUDY DESIGN

Narrative overview and summary.

OBJECTIVES

The objective of this introductory manuscript is to provide an overview of the effort that was undertaken to establish clinical practice guidelines for a number of important topics in spinal cord injury (SCI). These topics included: 1. The role and timing of surgical decompression after acute traumatic SCI; 2. The hemodynamic management of acute traumatic SCI; and 3. The definition, diagnosis, and management of intra-operative SCI. Here, we introduce the rationale for the guidelines, the methodology utilized, and summarize how the topics are addressed within various manuscripts of this Focus Issue.

METHODS

The key clinical questions were defined using the PICO format for treatment reviews (patient; intervention; comparison; outcomes) or PPO format (patient, prognostic factor, outcomes) for risk factor review. Multi-disciplinary, international guideline development groups (GDGs) were established to evaluate and collate the available evidence in a rigorous, systematic manner, followed by a review of systematically obtained evidence within the framework of the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) criteria and application of the Evidence to Decision process. Consensus meetings, using a modified Delphi approach, were held with the multidisciplinary, international GDGs using online video-conferencing technology and anonymous voting to develop the final recommendations for each of the topics addressed. All systematic review protocols followed PRISMA standards and were registered on PROSPERO; all potential conflicts were vetted in an open and transparent manner. The funders (AO Spine and Praxis Spinal Cord Institute) had no influence over editorial content or the guidelines process).

RESULTS

Updated guidelines were established for the timing of surgical decompression after acute SCI, with surgical decompression within 24 hours of injury now "recommended" as a treatment option. Updated guidelines were also established for hemodynamic management, with an expanded target range for mean arterial pressure (MAP) of 75-80 to 90-95 mmHg for between 3 to 7 days post-injury now "suggested" as a treatment option. The available literature mandated scoping and systematic reviews on the topic of intra-operative SCI, and this resulted in manuscripts to address the definition, frequency, and risk factors, to define the role of intra-operative neuromonitoring, and to suggest an evidence-based care pathway for management.

CONCLUSION

A rigorous process following GRADE standards was undertaken to review the available evidence and establish guideline recommendations around the role and timing of surgery in acute SCI, optimal hemodynamic management of acute SCI and the prevention, diagnosis and management of intraoperative SCI. This effort also identified key knowledge gaps and future directions for study, which will serve to refine these recommendations in the future.

A Clinical Practice Guideline for the Management of Patients With Acute Spinal Cord Injury: Recommendations on Hemodynamic Management

STUDY DESIGN

Clinical practice guideline development following the GRADE process.

OBJECTIVES

Hemodynamic management is one of the only available treatment options that likely improves neurologic outcomes in patients with acute traumatic spinal cord injury (SCI). Augmenting mean arterial pressure (MAP) aims to improve blood perfusion and oxygen delivery to the injured spinal cord in order to minimize secondary ischemic damage to neural tissue. The objective of this guideline was to update the 2013 AANS/CNS recommendations on the hemodynamic management of patients with acute traumatic SCI, acknowledging that much has been published in this area since its publication. Specifically, we sought to make recommendations on 1. The range of mean arterial pressure (MAP) to be maintained by identifying an upper and lower MAP limit; 2. The duration of such MAP augmentation; and 3. The choice of vasopressor. Additionally, we sought to make a recommendation on spinal cord perfusion pressure (SCPP) targets.

METHODS

A multidisciplinary guideline development group (GDG) was formed that included health care professionals from a wide range of clinical specialities, patient advocates, and individuals living with SCI. The GDG reviewed the 2013 AANS/CNS guidelines and voted on whether each recommendation should be endorsed or updated. A systematic review of the literature, following PRISMA standards and registered in PROSPERO, was conducted to inform the guideline development process and address the following key questions: (i) what are the effects of goal-directed interventions to optimize spinal cord perfusion on extent of neurological recovery and rates of adverse events at any time point of follow-up? and (ii) what are the effects of particular monitoring techniques, perfusion ranges, pharmacological agents, and durations of treatment on extent of neurological recovery and rates of adverse events at any time point of follow-up? The GDG combined the information from this systematic review with their clinical expertise in order to develop recommendations on a MAP target range (specifically an upper and lower limit to target), the optimal duration for MAP augmentation, and the use of vasopressors or inotropes. Using methods outlined by the GRADE working group, recommendations were formulated that considered the balance of benefits and harms, financial impact, acceptability, feasibility and patient preferences.

RESULTS

The GDG suggested that MAP should be augmented to at least 75-80 mmHg as the "lower limit," but not actively augmented beyond an "upper limit" of 90-95 mmHg in order to optimize spinal cord perfusion in acute traumatic SCI. The quality of the evidence around the "target MAP" was very low, and thus the strength of this recommendation is weak. For duration of hemodynamic management, the GDG "suggested" that MAP be augmented for a duration of 3-7 days. Again, the quality of the evidence around the duration of MAP support was very low, and thus the strength of this recommendation is also weak. The GDG felt that a recommendation on the choice of vasopressor or the use of SCPP targets was not warranted, given the dearth of available evidence.

CONCLUSION

We provide new recommendations for blood pressure management after acute SCI that acknowledge the limitations of the current evidence on the relationship between MAP and neurologic recovery. It was felt that the low quality of existing evidence and uncertainty around the relationship between MAP and neurologic recovery justified a greater range of MAP to target, and for a broader range of days post-injury than recommended in previous guidelines. While important knowledge gaps still remain regarding hemodynamic management, these recommendations represent current perspectives on the role of MAP augmentation for acute SCI.

Microcirculatory Alterations in Cardiac Surgery: A Comprehensive Guide

Microcirculation is essential for cellular life and its functions. It comprises a complex network of capillaries, arterioles, and venules, which distributes oxygenated blood across and within organs based on regional metabolic demands. Because previous research indicated that organ function is linked to microcirculatory function, it is crucial to maintain sufficient and effective microcirculatory function during major surgery. Impaired microcirculation can lead to inadequate tissue perfusion, potentially resulting in perioperative complications and an unfavorable outcome. Indeed, changes in microcirculation in cardiovascular disease and cardiac surgery have a direct correlation with prolonged stays in the postoperative intensive care unit and high mortality rates within 30 days. Additionally, cardiopulmonary bypass, a regularly employed method in cardiac surgery, has been proven to induce microcirculatory malfunction and, thus, lead to postoperative multiple organ dysfunction. As global hemodynamic parameters can remain stable or improve, whereas microcirculation is still compromised, tracking microcirculatory variables could lead to the development of targeted microcirculatory treatment within hemodynamic management. Therefore, it is necessary to enhance the use of microcirculatory monitoring in the medical domain to assist physicians in the therapeutic management of patients undergoing cardiac surgery. This potentially can lead to better hemodynamic management and outcomes. This review article concentrates on the use of handheld video microscopes for real-time microcirculatory assessment of cardiac surgery patients in the immediate and early postoperative period. Emphasis is placed on integrating microcirculatory monitoring with conventional hemodynamic monitoring in the therapeutic management of patients undergoing cardiac surgery.

Current Practice of Acute Spinal Cord Injury Management: A Global Survey of Members from the AO Spine

STUDY DESIGN

Cross-sectional, international survey.

OBJECTIVES

To examine current international practices as well as knowledge, adoption, and barriers to guideline implementation for acute spinal cord injury (SCI) management.

METHODS

A survey was distributed to members of AO Spine. The questionnaire was structured to obtain demographic data and preferred acute SCI practices surrounding steroid use, hemodynamic management, and timing of surgical decompression.

RESULTS

593 members completed the survey including orthopaedic surgeons (54.3%), neurosurgeons (35.6%), and traumatologists (8.4%). Most (61.2%) respondents were from low and middle-income countries (LMICs). 53.6% of physicians used steroids for the treatment of acute SCIs. Respondents from LMICs were more likely to administer steroids than HICs (178 vs. 78; P < .001). 331 respondents (81.5%) answered that patients would receive mean arterial pressure (MAP) targeted treatment. In LMICs, SCI patients were less likely to be provided with MAP-targeted treatment (76.9%) as compared to HICs (89%; P < .05). The majority of respondents (87.8%) reported that patients would benefit from early decompression. Despite overwhelming evidence and surgeons' responses that would offer early surgery, 62.4% of respondents stated they encounter logistical barriers in their institutions. This was particularly evident in LMICs, where 57.9% of respondents indicated that early intervention was unlikely to be accomplished, while only 21.1% of respondents from HICs stated the same (P < .001).

CONCLUSION

This survey highlights challenges in the implementation of standardized global practices in the management of acute SCI. Future research efforts will need to refine SCI guidelines and address barriers to guideline implementation.

The 2023 AO Spine-Praxis Guidelines in Acute Spinal Cord Injury: What Have We Learned? What Are the Critical Knowledge Gaps and Barriers to Implementation?

STUDY DESIGN

Narrative summary of the 2023 AO Spine-Praxis clinical practice guidelines for management in acute spinal cord injury (SCI).

OBJECTIVES

The objective of this article is to summarize the key findings of the clinical practice guidelines for the optimal management of traumatic and intraoperative SCI (ISCI). This article will also highlight potential knowledge translation opportunities for each recommendation and discuss important knowledge gaps and areas of future research.

METHODS

Systematic reviews were conducted according to accepted methodological standards to evaluate the current body of evidence and inform the guideline development process. The summarized evidence was reviewed by a multidisciplinary guidelines development group that consisted of international multidisciplinary stakeholders. The Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) approach was used to rate the certainty of the evidence for each critical outcome and the "evidence to recommendation" framework was used to formulate the final recommendations.

RESULTS

The key recommendations regarding the timing of surgical decompression, hemodynamic management, and the prevention, diagnosis, and management of ISCI are summarized. While a strong recommendation was made for early surgery, further prospective research is required to define what constitutes sufficient surgical decompression, examine the role of ultra-early surgery, and assess the impact of early surgery in different SCI phenotypes, including central cord syndrome. Furthermore, additional investigation is required to evaluate the impact of mean arterial blood pressure targets on neurological recovery and to determine the utility of spinal cord perfusion pressure measurements. Finally, there is a need to examine the role of neuroprotective agents for the treatment of ISCI and to prospectively validate the new AO Spine-Praxis care pathway for the prevention, diagnosis, and management of ISCI. To optimize the translation of these guidelines into practice, important barriers to their implementation, particularly in underserved areas, need to be explored. Ultimately, these recommendations will help to establish more personalized approaches to care for SCI patients.

CONCLUSIONS

The recommendations from the 2023 AO Spine-Praxis guidelines not only highlight the current best practice in the management of SCI, but reveal critical knowledge gaps and barriers to implementation that will help to guide further research efforts in SCI.

Advanced artificial intelligence-guided hemodynamic management within cardiac enhanced recovery after surgery pathways: A multi-institution review

Objective

The study objective was to report early outcomes of integrating Hypotension Prediction Index-guided hemodynamic management within a cardiac enhanced recovery pathway on total initial ventilation hours and length of stay in the intensive care unit.

Methods

A multicenter, historical control, observational analysis of implementation of a hemodynamic management tool within enhanced recovery pathways was conducted by identifying cardiac surgery cases from 3 sites during 2 time periods, August 1 to December 31, 2019 (preprogram), and April 1 to August 31, 2021 (program). Reoperations, emergency (salvage), or cases requiring mechanical assist were excluded. Data were extracted from electronic medical records and chart reviews. Two primary outcome variables were length of stay in the intensive care unit (using Society of Thoracic Surgeons definitions) and acute kidney injury (using modified Kidney Disease Improving Global Outcomes criteria). One secondary outcome variable, total initial ventilation hours, used Society of Thoracic Surgeons definitions. Differences in length of stay in the intensive care unit and total ventilation time were analyzed using Kruskal-Wallis and stepwise multiple linear regression. Acute kidney injury stage used chi-square and stepwise cumulative logistic regression.

Results

A total of 1404 cases (795 preprogram; 609 program) were identified. Overall reductions of 6.8 and 4.4 hours in intensive care unit length of stay (P = .08) and ventilation time (P = .03) were found, respectively. No significant association between proportion of patients identified with acute kidney injury by stage and period was found.

Conclusions

Adding artificial intelligence-guided hemodynamic management to cardiac enhanced recovery pathways resulted in associated reduced time in the intensive care unit for patients undergoing nonemergency cardiac surgery across institutions in a real-world setting.

Perioperative clinical practice in liver transplantation: a cross-sectional survey

PURPOSE

The objective of this study was to describe some components of the perioperative practice in liver transplantation as reported by clinicians.

METHODS

We conducted a cross-sectional clinical practice survey using an online instrument containing questions on selected themes related to the perioperative care of liver transplant recipients. We sent email invitations to Canadian anesthesiologists, Canadian surgeons, and French anesthesiologists specialized in liver transplantation. We used five-point Likert-type scales (from "never" to "always") and numerical or categorical answers. Results are presented as medians or proportions.

RESULTS

We obtained answers from 130 participants (estimated response rate of 71% in Canada and 26% in France). Respondents reported rarely using transesophageal echocardiography routinely but often using it for hemodynamic instability, often using an intraoperative goal-directed hemodynamic management strategy, and never using a phlebotomy (medians from ordinal scales). Fifty-nine percent of respondents reported using a restrictive fluid management strategy to manage hemodynamic instability during the dissection phase. Forty-two percent and 15% of respondents reported using viscoelastic tests to guide intraoperative and postoperative transfusions, respectively. Fifty-four percent of respondents reported not pre-emptively treating preoperative coagulations disturbances, and 91% reported treating them intraoperatively only when bleeding was significant. Most respondents (48-64%) did not have an opinion on the maximal graft ischemic times. Forty-seven percent of respondents reported that a piggyback technique was the preferred vena cava anastomosis approach.

CONCLUSION

Different interventions were reported to be used regarding most components of perioperative care in liver transplantation. Our results suggest that significant equipoise exists on the optimal perioperative management of this population.

Left Heart and Systemic Arterial Circulation Air Embolus During CT-Guided Lung Biopsy

A transthoracic needle biopsy (TTNB) of the lung, commonly referred to as a "lung biopsy," is a commonly performed procedure in Interventional Radiology. It is usually associated with well-known risks including pneumothorax and hemothorax. One of the rare and lesser-known risks of TTNB, however, is a phenomenon called an air embolism. The term "air embolism" alone may be somewhat ambiguous, as it could indicate i) air entering the systemic veins, or ii) air entering the pulmonary veins. Here, we present a case of an air embolus entering the pulmonary veins. The pulmonary veins naturally drain into the left side of the heart (left atrium and ventricle) which provides oxygenated blood to the major arteries of the body including the coronary, carotid, and major abdominal visceral branches. Therefore, an air embolism in this vasculature can lead to potentially devastating hemodynamic consequences downstream.

Postoperative management

Most patients undergoing major aortic surgery have multiple comorbidities and are at high risk of postoperative complications that affect multiple organ systems. Different aortic pathologies and surgical repair techniques have specific impact on the postoperative course. Ischemia-reperfusion injury is the common denominator in aortic surgery and influences the integrity of end-organ function. Common postoperative problems include hemodynamic instability due to the immediate inflammatory response, renal impairment, spinal cord ischemia, respiratory failure with prolonged mechanical ventilation, and gastrointestinal symptoms such as ileus or mesenteric ischemia. Focused care bundles to establish homeostasis and a team working toward an early functional recovery determine the success of effective rehabilitation and outcomes after aortic surgery.

Sepsis-associated acute kidney injury: macrohemodynamic and microhemodynamic alterations in the renal circulation

Traditionally, renal ischemia has been regarded as central to the pathogenesis of sepsis-associated acute kidney injury (SA-AKI). Accordingly, hemodynamic management of SA-AKI has emphasized restoration of renal perfusion, whereas, experimentally, ischemia reperfusion models have been emphasized. However, in human beings, SA-AKI usually is accompanied by hyperdynamic circulation. Moreover, clinical and experimental evidence now suggests the importance of inflammatory mechanisms in the development of AKI and microcirculatory dysfunction more than systemic alteration in renal perfusion. In this review, we examine systemic, regional, and microcirculatory hemodynamics in SA-AKI, and attempt to rationalize the hemodynamic management of this condition.

Principles of pharmacologic hemodynamic management and closed-loop systems

Every day, physicians in critical-care settings are challenged with the hemodynamic management of patients with severe cardiovascular derangements. There is a potential role for closed-loop (automated) systems to assist clinicians in managing these patients and growing interest in the possible applications. In this review, we discuss the basic principles of critical-care hemodynamic management and the closed-loop systems that have been developed to help in this setting.

Hemodynamic monitoring and management of patients undergoing high-risk surgery: a survey among Chinese anesthesiologists

Hemodynamic monitoring and optimization improve postoperative outcome during high-risk surgery. However, hemodynamic management practices among Chinese anesthesiologists are largely unknown. This study sought to evaluate the current intraoperative hemodynamic management practices for high-risk surgery patients in China. From September 2010 to November 2011, we surveyed anesthesiologists working in the operating rooms of 265 hospitals representing 28 Chinese provinces. All questionnaires were distributed to department chairs of anesthesiology or practicing anesthesiologists. Once completed, the 29-item questionnaires were collected and analyzed. Two hundred and 10 questionnaires from 265 hospitals in China were collected. We found that 91.4% of anesthesiologists monitored invasive arterial pressure, 82.9% monitored central venous pressure (CVP), 13.3% monitored cardiac output (CO), 10.5% monitored mixed venous saturation, and less than 2% monitored pulse pressure variation (PPV) or systolic pressure variation (SPV) during high-risk surgery. The majority (88%) of anesthesiologists relied on clinical experience as an indicator for volume expansion and more than 80% relied on blood pressure, CVP and urine output. Anesthesiologists in China do not own enough attention on hemodynamic parameters such as PPV, SPV and CO during fluid management in high-risk surgical patients. The lack of CO monitoring may be attributed largely to the limited access to technologies, the cost of the devices and the lack of education on how to use them. There is a need for improving access to these technologies as well as an opportunity to create guidelines and education for hemodynamic optimization in China.

Early intensive versus minimally invasive approach to postoperative hemodynamic management after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

The results of previous studies suggest that early goal-directed fluid therapy (EGDT) reduces delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage, but the effects of EGDT on clinical outcomes are still unclear. This study aimed to determine whether EGDT improves outcomes compared with standard less-invasive hemodynamic therapy.

METHODS

This study included 160 patients treated within 24 hours after subarachnoid hemorrhage, randomized to receive either (1) EGDT guided by preload volume and cardiac output monitored by transpulmonary thermodilution (treatment group) or (2) standard therapy guided by fluid balance or central venous pressure, assisted by uncalibrated less-invasive cardiac output monitoring during hyperdynamic therapy in patients with clinical or radiological indications of DCI (control group). DCI determined by clinical or radiological findings and functional outcome determined by the modified Rankin Scale score at 3 months were compared between groups.

RESULTS

For all clinical grades combined, there were no significant differences in the rates of DCI (33% versus 42%; P=0.33) or modified Rankin Scale score of 0 to 3 at 3 months (67% versus 57%; P=0.22) between the 2 groups. For patients with poor clinical grade, those who received EGDT had a significantly lower rate of DCI (5% versus 14%; P=0.036), modified Rankin Scale score of 0 to 3 at 3 months (52% versus 36%; P=0.026), and shorter length of intensive care unit stay (14 versus 17 days; P=0.043) than those who received standard therapy.

CONCLUSIONS

EGDT is beneficial for reducing DCI and improving postoperative functional outcome in patients with poor clinical grade.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: UMIN000007509.