The incidence of myocardial injury following post-operative Goal Directed Therapy

Perioperative transesophageal echocardiography for non-cardiac surgery

PURPOSE

The use of transesophageal echocardiography (TEE) has evolved to include patients undergoing high-risk non-cardiac procedures and patients with significant cardiac disease undergoing non-cardiac surgery. Implementation of basic TEE education in training programs has increased across a broad spectrum of procedures in the perioperative arena. This paper describes the use of perioperative TEE in non-cardiac surgery and provides an overview of the basic TEE examination.

PRINCIPAL FINDINGS

Perioperative TEE is used to monitor hemodynamic parameters in non-cardiac procedures where there is a high risk of hemodynamic instability. Its use extends to include moderate-risk procedures for patients with significant cardiac diseases such as low ejection fraction, hypertrophic cardiomyopathy, severe valve lesions, or congenital heart disease. Vascular procedures involving the aorta, blunt trauma, and liver transplantation are all examples of procedures that may benefit from TEE. Transesophageal echocardiography examination allows assessment of volume status, ventricular function, diagnosis of gross valvular pathology and pericardial tamponade, as well as close monitoring of cardiac output, response to therapy, and the impact of ongoing surgical manipulation. In patients with unexplained and unexpected hemodynamic instability, "rescue TEE" can be used to help identify the underlying cause.

CONCLUSIONS

Perioperative TEE is emerging as a preferred tool to manage hemodynamics in high-risk procedures and in high-risk patients undergoing non-cardiac surgery. A rescue TEE examination protocol is a helpful approach for early identification of the etiology of hemodynamic instability.

Perioperative myocardial injury in patients receiving cardiac output-guided haemodynamic therapy: a substudy of the OPTIMISE Trial

BACKGROUND

Evidence suggests that cardiac output-guided haemodynamic therapy algorithms improve outcomes after high-risk surgery, but there is some concern that this could promote acute myocardial injury. We evaluated the incidence of myocardial injury in a perioperative goal-directed therapy trial.

METHODS

Patients undergoing major gastrointestinal surgery (n=723) were randomly assigned to cardiac output-guided haemodynamic therapy (intervention group) or usual care as part of the OPTIMISE trial. At four participating sites, 288 patients were enrolled in a biomarker substudy. Serum high-sensitivity cardiac troponin I (TnI) concentration and N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration were measured before and at 24 and 72 h after surgery.

RESULTS

Median preoperative TnI and NT-ProBNP concentrations were 4.3 ng litre(-1) and 144 pg ml(-1), respectively. After surgery, 67 (46%) patients in the intervention group and 68 (48%) patients receiving usual care had TnI concentrations above the 99th centile upper reference limit (P=0.82). Peak serum TnI concentration was similar in the intervention and usual care groups (median [interquartile range]: 10.0 [5.3-21.5] vs 7.8 [5.0-21.8] ng litre(-1); P=0.85), and no differences were observed in serum TnI concentrations over 72 h (repeated-measures anova, P=0.51). Likewise, there were no differences in peak NT-proBNP concentration between intervention and usual care groups (645 [362-1169] vs 659 [381-1028] pg ml(-1); P=0.86) or in serial NT-proBNP concentrations over 72 h (P=0.20).

CONCLUSIONS

Myocardial injury is common among patients undergoing major gastrointestinal surgery. In this study, the frequency was not affected by cardiac output-guided fluid and low-dose inotropic therapy.

Perioperative Haemodynamic Optimisation

During the latest years, a number of studies have confirmed the benefits of perioperative haemodynamic optimisation on surgical mortality and postoperative complication rate. This process requires the use of advanced haemodynamic monitoring with the purpose of guiding therapies to reach predefined goals. This review aim to present recent evidence on perioperative goal directed therapy (GDT), with an emphasis in some aspects that may merit further investigation. In order to maximise the benefits on outcomes, GDT must be implemented as early as possible; intravascular volume optimisation should be in accordance with the response of the preload-reserve, goals should be individualised and adequacy of the intervention must be also assessed; non-invasive or minimally invasive monitoring should be used and, finally, side effects of every therapy should be taken into account in order to avoid undesired complications. New drugs and technologies, particularly those exploring the venous side of the circulation, may improve in the future the effectiveness and facilitate the implementation of this group of therapeutic interventions.

[Volume replacement in intensive care medicine]

Volume substitution represents an essential component of intensive care medicine. The amount of fluid administered, the composition and the timing of volume replacement seem to affect the morbidity and mortality of critically ill patients. Although restrictive volume strategies bear the risk of tissue hypoperfusion and tissue hypoxia in hemodynamically unstable patients liberal strategies favour the development of avoidable hypervolemia with edema and resultant organ dysfunction. However, neither strategy has shown a consistent benefit. In order to account for the heavily varying oxygen demand of critically ill patients, a goal-directed, demand-adapted volume strategy is proposed. Using this strategy, volume replacement should be aligned to the need to restore tissue perfusion and the evidence of volume responsiveness. As the efficiency of volume resuscitation for correction of tissue hypoxia is time-dependent, preload optimization should be completed in the very first hours. Whether colloids or crystalloids are more suitable for this purpose is still controversially discussed. Nevertheless, a temporally limited use of colloids during the initial stage of tissue hypoperfusion appears to represent a strategy which uses the greater volume effect during hypovolemia while minimizing the risks for adverse reactions.

Defining higher-risk surgery

PURPOSE OF REVIEW

Defining the contemporary high-risk noncardiac surgical population using objective clinical outcomes data is paramount for the rational allocation of healthcare resources, truly informed patient consent and improving patient-centered outcomes.

RECENT FINDINGS

Data from independent healthcare systems have identified that the development, and consequences, of postoperative morbidity extend beyond the immediate postoperative hospital period and confer substantially increased risk of death. Cardiac insufficiency, rather than the relatively heavily explored paradigm of perioperative cardiac ischemia, is emerging as the dominant factor associated with excess risk of prolonged postoperative morbidity. The development of prospective, validated, time-sensitive morbidity data collection tools has also helped define patients at higher risk of noncardiac morbidities and short-term perioperative outcomes.

SUMMARY

Higher risk surgical patients present an increasingly major challenge for healthcare resource utilization. Detailed outcome studies using validated morbidity tools are urgently required to establish the extent to which postoperative morbidity may be predicted. Robust identification of patients at the highest risk of perioperative morbidity may permit further clinic-to-bench translational understanding of the pathophysiologic mechanisms underlying postoperative organ dysfunction. Defining the high-risk surgical patient population is as critically important for global public health planning as it is for the perioperative team.

The use of early intervention to prevent postoperative complications

PURPOSE OF REVIEW

The incidence of complications following major surgery is surprisingly high. Patients who develop complications suffer a reduction in long-term survival. This review aims to explore recent advances in the management of surgical patients aimed at preventing postoperative complications.

RECENT FINDINGS

Identifying patients prior to surgery who are at risk of a poor outcome remains challenging. There are a number of scoring systems to assist clinical risk assessment. Recent work has investigated the use of plasma biomarkers for perioperative risk prediction. Therapies aimed at reducing complication rates by attempting to improve tissue oxygen delivery include goal-directed haemodynamic therapy and postoperative noninvasive ventilation. The role of perioperative beta-adrenoceptor antagonists remains unclear. Other important measures include the use of a surgical safety checklist and thromboprophylaxis.

SUMMARY

Current systems for the identification and treatment of high-risk surgical patients are inadequate. Further research is required to establish the optimal approach to the identification and management of the high-risk surgical patient.