Post-operative hypotension is a common and clinically significant challenge, often linked to poor outcomes such as organ dysfunction, prolonged recovery, and increased mortality. Vasopressors are routinely used to manage this condition. Until recently, their use in the post-operative setting lacked robust, large-scale data.
In this article, we will discuss the SQUEEZE Study. This is the first international observational study of its kind to address this gap. Conducted in 228 hospitals in 42 countries, including UK centres such as University College London (UCL), and Royal Surrey Hospital, the study analysed data from 25,675 patients undergoing non-cardiac surgery.
Its key findings offer a global snapshot of vasopressor use and raise important questions about variability, monitoring, and outcomes, with direct relevance to NHS perioperative care.
The involvement of the UK centres provides valuable insights through which to compare the UK’s national practice with international trends. It also allows for additional reflections, considering alternatives and opportunities for improvement in perioperative care.
Key Findings from the Study
Incidence and Variation in Vasopressor Use
One noteworthy finding of the SQUEEZE Study is the relatively low incidence rate of post-operative vasopressor use, with an average of only 3.9% of patients receiving infusions following non-cardiac surgery.
However, there is a wide degree of variation between hospitals which the average rate of incidence hides. Usage rates between hospitals range from 0% to 18%. The variations do not also correlate with the mix of patient cases, or surgical complexity. It is therefore possible that institutional protocols, clinician preferences, and resource availability could be a greater influence on practice than clinical need, potentially raising important questions about consistency in post-operative care.
The Impact on Patient Outcomes
Patients who received post-operative vasopressors experienced significantly worse outcomes. The in-hospital mortality rate among these patients was 15.5%, compared to just 2.1% in those who did not receive vasopressors.
Beyond mortality, vasopressor use was associated with a higher incidence of severe physiological compromise, or organ dysfunction, for example, renal failure, cardiac arrhythmias, and the need for parenteral nutrition.
These patients also had longer hospital stays, with a median duration of 10–12 days, compared to 3 days for their counterparts.
These findings underscore the need for careful consideration before initiating vasopressor therapy and highlight the importance of monitoring and support in the post-operative period.
Choice of Vasopressor and Monitoring Practices
Across the study, norepinephrine emerged as the most used vasopressor, reflecting its widespread acceptance as a first-line agent for hypotension. However, the study revealed a concerning gap in monitoring practices, specifically, the rare use of cardiac output monitoring and echocardiography to guide vasopressor therapy.
This suggests that many treatment decisions were made without objective data on the patient’s haemodynamic status, potentially leading to inappropriate or suboptimal management. The lack of physiological insight and data may therefore contribute to the poor outcomes observed and highlights a need for better integration of monitoring technologies into perioperative care.
Clinical Implications – Understanding the Problem
The considerable variability in post-operative vasopressor use observed in the SQUEEZE Study, prompts a reflection on current clinical practice. Why do some hospitals administer vasopressors more frequently than others? Is this variation driven by patient need, or does it reflect differences in training, institutional protocols, and resource availability?
It would appear in the study, that the variability could not be explained by patient illness severity, type of surgery or national income level. Instead, it suggests hospital culture, individual clinician preferences and local protocols are most likely responsible for the differences between hospitals.
It is clear, the findings suggest a current lack of standardised approaches to managing post-operative hypotension, and a significant gap between guidelines and practice, with clinicians making decisions based on subjective clinical judgement, with cardiac output monitoring rarely used. This suggests a need for:
- Defined blood pressure targets to guide intervention thresholds
- Objective monitoring tools such as cardiac output monitors and echocardiography, to inform clinical decisions with real-time, accurate data.
- Informed decision making using structured frameworks, supporting consistent vasopressor initiation and continued use in non-cardiac post-operative care
For NHS perioperative teams, including anaesthetists and perioperative teams, these findings are particularly relevant. They suggest opportunities to refine Enhanced Recovery After Surgery (ERAS) pathways and critical care protocols by integrating more consistent approaches to hypotension management. Standardisation could help reduce unwarranted variation, improve patient outcomes, safety and care, and support more efficient use of resources.
Role of Monitoring and Delivery Systems – Why It Matters
The SQUEEZE Study underscores a critical gap in post-operative care: the lack of objective monitoring when administering vasopressors. Despite the known risks associated with hypotension and vasopressor therapy, most treatment decisions were made without the support of cardiac output monitoring or echocardiography. This reliance on clinical impression rather than precise physiological data can lead to both overuse and underuse of vasopressors, with potentially serious consequences.
Accurate blood pressure and cardiac output monitoring are essential tools in guiding safe and effective therapy. Without them, clinicians may struggle to distinguish between different causes of hypotension, whether due to preload depletion, impaired contractility, or reduced afterload. This diagnostic uncertainty can result in non-personalised treatment strategies that fail to address the underlying issue.
Haemodynamic monitoring enables a precise and more tailored approach. By identifying the specific physiological deficit, clinicians can then select the most appropriate intervention, whether that’s fluid resuscitation, vasopressor support, or inotropic therapy, supporting more efficient use of resources and improving outcomes.
Therefore, the findings from SQUEEZE makes a strong case for integrating reliable monitoring systems into routine post-operative care. They are not just technical tools, they are clinical enablers of personalised, evidence-based decision-making.
Conclusion
The SQUEEZE Study has brought to light a critical gap in perioperative care: the management of post-operative hypotension remains inconsistent, under-monitored, and underrepresented in clinical guidance. Despite its association with increased mortality, organ dysfunction, and prolonged hospital stays, vasopressor use continues to vary widely.
This calls for a renewed focus in both guidelines and training, ensuring that clinicians are equipped to make informed, data-driven decisions. The role of reliable monitoring equipment is central to this effort. While the study does not endorse specific technologies, it clearly positions objective assessment tools as essential for safe and effective vasopressor therapy.
For UK hospitals, the findings offer a timely opportunity to audit current practice, identify unwarranted variation, and align with emerging international standards. This gives the opportunity to embed more consistent approaches within Enhanced Recovery After Surgery (ERAS) pathways and critical care protocols, thus improving outcomes and resource use.
UK clinicians and researchers are well placed to lead this change. By engaging with the data by using reliable haemodynamic monitoring tools, reflecting on local practice, and contributing to future guideline development, the NHS can take meaningful steps towards standardising care and improving patient safety in the post-operative setting.
References:
Jammer I, Creagh-Brown B, Wunsch H, Forni L, Moonesinghe R. The SQUEEZE Study – Post-operative vasopressor use following non-cardiac surgery: an international observational study. European Society of Anaesthesiology and Intensive Care. Available from: https://esaic.org/study/squeeze-study/
