Ten years of acute care surgery in Singapore: evolution, outcomes and future challenges

Abstract

Background

Acute Care Surgery (ACS) has emerged as a structured solution to challenges in emergency general surgery (EGS), including subspecialisation, fragmented coverage, and delays in operative care.

Methods

This narrative review outlines the global ACS evolution and examines Singapore’s experience over the past decade, focusing on implementation models, outcomes, and ongoing challenges.

Results

Since 2014, Singapore’s public hospitals have adopted variations of the ACS framework, ranging from consultant of the week rosters to dedicated full time ACS teams. These models have improved timeliness of care, efficiency, and surgical training. Innovations such as Emergency Laparotomy Pathways and abscess protocols reduced delays and improved perioperative coordination. Local outcomes demonstrate reduced time to intervention by 30–40%, shorter hospital stays by 1-2d and sustained improvements in morbidity and mortality. However, challenges persist in trauma workforce sustainability, registrar training variability, theatre access, and the absence of national credentialing.

Conclusion

ACS has improved the delivery of emergency and trauma surgery in Singapore. To sustain these gains, national credentialing, workforce planning, and structured training frameworks are required to secure ACS as a core part of the surgical system.

Introduction

Acute Care Surgery (ACS) emerged as a strategic response to rising subspecialisation, fragmented on call coverage, and delays in emergency general surgical care [1, 2]. It brought trauma, emergency general surgery (EGS), and surgical critical care under a single, consultant led specialty which aimed to restore timely, coordinated care for acutely ill general surgical patients. Over time, ACS has evolved into a recognised model for managing high acuity and volume general surgical conditions, with adaptation across healthcare systems in Europe, Australasia, and parts of Asia [3–5].

Singapore began adopting ACS principles in 2014. What started as an isolated initiative has grown into a national effort to provide timely consultant led care for EGS and trauma patients [6, 7]. Today, multiple restructured hospitals operate variations of ACS models of care with some protected operating access, structured handovers, and multidisciplinary perioperative collaboration. Many of these models draw inspiration from international benchmarks, particularly the 12-point Acute Surgical Unit (ASU) framework developed by General Surgeons Australia (GSA) [8].

Methods

This narrative review was conducted using PubMed, Google Scholar and local institutional archives. The search included English-language articles from 2000 to 2025 focusing on Acute Care Surgery (ACS), Emergency General Surgery (EGS) and trauma systems in Singapore and internationally. Reference lists of relevant papers were screened for additional studies. Key themes were implementation models, outcomes and challenges.

ACS development and outcomes in the United States

Before ACS, EGS in the United States was managed by fragmented on call systems using limited trained trauma or general surgeons to staff rosters [9]. These inconsistencies in senior input, delays in operative intervention, and poor continuity of care were compounded by a growing trend toward subspecialisation across surgical disciplines.

In 2005, the American Association for the Surgery of Trauma (AAST) formally proposed ACS as a unified model that would consolidate trauma, EGS, and surgical critical care into a single specialty. Its core design emphasised 24 h consultant presence, dedicated access to emergency theatres, structured team handovers, and robust integration with ICU teams. The key aims were to restore speed, cohesion, and safety in managing high acuity cases. The model quickly gained traction. Early evaluations showed that ACS hospitals consistently achieved shorter times to surgery, lower complication rates and mortality [10]. Studies have also reported enhanced patient outcomes, improved surgical trainee and fellowship experience following ACS implementation, though the program structure and credentialling are not uniform [11, 12].

For specific common conditions such as appendicitis and biliary disease, ACS models have consistently showed improved outcomes including faster access to OT with more efficient use of emergency operating resources [13].

Over 20 U.S. centres now offer ACS fellowships, with program structure and credentialing evolving at a rapid pace [14]. Importantly, ACS has helped preserve generalist surgical skills and maintained exposure to high acuity cases, counterbalancing the steady drift toward organ specific sub specialised training.

Despite its strengths, ACS remains inconsistently implemented outside of academic centres. Manpower shortages, funding limitations, and varying institutional priorities have led to patchy uptake across community hospitals. Standardisation of EGS delivery was a key focus of the 2022 American College of Surgeons general surgery verification program which focused on resources, data, clinical pathways and value added care for pilot sites across the USA [15].

Global trends and evolution for ACS models of care

ACS has been adapted around the world, evolving to suit different healthcare systems. Local implementation varies though some core elements remain such as consultant led care, prioritised access to theatres, and integrated multidisciplinary decision making. However, expansion is limited due to non uniform resource availability and priorities [3, 16].

Both Australia and New Zealand have adopted structured Acute Surgical Units (ASUs), guided by the General Surgeons Australia (GSA) 12-point checklist (Table 1) [8]. These units are typically staffed by general surgeons on a rotating weekly basis, with protected daytime theatre access and a clear separation from elective services. The model is supported across many institutions driven by a desire to reduce after hours operating and improve patient care but recognising that manpower remains a common limiting factor [17].

Table 1.

General surgeons Australia (GSA) 12-point plan for acute surgical units (ASUs)

	Component	Description
1	Dedicated emergency theatre time	Allocated theatre sessions during daytime to reduce after-hours operations.
2	Daily consultant ward rounds	Consultant led rounds every day, including weekends.
3	Protected consultant time	Consultants are rostered off elective duties to focus on acute care.
4	Registrar and resident continuity	Dedicated junior teams provide consistent inpatient care.
5	Structured handover	Formal, documented handovers between shifts to maintain continuity.
6	Early senior decision-making	Consultants involved at the time of patient admission and operative planning.
7	Audit and data collection	Ongoing outcome tracking to support quality improvement.
8	Timely access to diagnostics	Prioritised imaging and pathology for acute surgical patients.
9	Defined clinical pathways	Standardised protocols for common emergency conditions.
10	Education and training focus	Integration of training and supervision for surgical residents.
11	Team based care	Collaboration across disciplines, including anaesthesia, radiology, and nursing.
12	Service governance	Clear unit leadership with defined roles, oversight, and accountability.

The United Kingdom has adopted a similar direction, with focus on providing senior directed care, prompt decision making, improved training and competency and standardised protocols [4]. The framework for EGS care encourages dedicated emergency theatre access within six hours, and institutional participation in the National Emergency Laparotomy Audit (NELA). Although anaesthesia departments continue to lead critical care in the UK, close collaboration between specialties has improved perioperative coordination and audit driven practice.

In Asia, including South Korea and China, ACS models of care have largely developed at a hospital or regional level. Studies from tertiary centres in these countries show reduced time to intervention and improved complication rates following ACS adoption, as well as efforts to deal with ED crowding [18, 19].

In Latin America, several countries have introduced ACS style protocols centred around early consultant involvement, prioritised operative access, and emergency rosters. Despite ongoing limitations in ICU capacity and funding, a study from Ecuador showed improved clinical, efficiency and mortality outcomes after commencing their TACS (Trauma and acute care surgery) service [20].

Meanwhile, low and middle income countries (LMICs) face distinct resource constraints. The World Health Organization’s Global Initiative for Emergency and Essential Surgical Care (GIEESC) supports simplified hospital EGS frameworks, including nurse led protocols, essential surgical supply kits, and rural surgical outreach programmes [21]. Tool kits distributed to participating centres include CD’s with recommendations for standards in emergency surgical care in surgery, trauma, and anaesthesia.

ACS in Singapore

Singapore’s adoption of ACS represents an attempt to deliver timely, consultant led EGS and trauma care within a highly functioning public healthcare system. Since 2014, most restructured hospitals have attempted to introduce ACS frameworks tailored to their specific resources and surgical workforce. While the operational details vary, core elements such as daytime consultant oversight, dedicated team structures, some element of protected operating theatre access, and structured multidisciplinary handovers remain consistent.

Some institutions (Khoo Teck Puat, Ng Teng Fong, Woodlands Hospitals) have created ACS models of care built around the attending/consultant(s) of the week roster, covering multiple days in a row or Mon-Fri daytime only. This structure requires the on call surgeons to relieve themselves of elective duties for one week to focus entirely on emergency and trauma admissions during the day. Such models have improved continuity of care, accelerated decision making, and enabled faster access to theatres. After hours can still be handled through departmental rosters, with patients transferred back to the ACS team each morning. This is a sustainable model as it does not require trained or dedicated ACS surgeons, but rather a roster where one individual may cover the ACS roster every 1:12 weeks depending upon the senior manpower available.

Others such as Singapore General Hospital have adopted a specialised approach, with a standalone ACS team operating 24/7, independent of elective surgery with a dedicated team of junior staff to manage the inpatients. Two protected ACS operating lists are allocated weekly, enabling the team to manage high acuity cases in daylight hours, improving both efficiency and surgical training. For the subspecialty departments, the ‘freeing up’ of resources can allow for focused management of complex inpatients without the distraction of emergency cases particularly during the weekday. However, ACS surgeons, primarily focused on EGS and Trauma will still require sub-specialist assistance for management of complex cases e.g. Boerhaave’s perforation, Crohn’s complications, Mirizzi Syndrome or malignant obstructions.

Structured handover is a cornerstone of the ACS model. In any of the models of care prescribed handover from daytime to after-hours is mandatory as well as overnight to morning teams. Furthermore, rules surrounding the transfer of care to other surgical disciplines needs to be established a priori to expedite patient movement and limit disagreement on the ground. Handovers for patients in ICU or High dependency also assist to ensure the most critically ill patients’ care is consistent over a 24 h period. Lastly, consultant to consultant dialogue is encouraged such that agreement can be reached regarding appropriate disposition of patients.

It is also important to acknowledge that the establishment of good ACS practices does not necessarily require a dedicated ACS unit. Empowering individual surgeons to act as champions for quality care and ensuring strict compliance with agreed protocols even amongst those not routinely on ACS rosters, is vital. Good governance, regular audit and M&M and clarity of protocols are foundational even in hospitals where ACS patients are managed across generalists or those that practice intermittently.

Management of trauma is an integral part of general surgery resident training. Local programs require senior residents to complete a posting focused on trauma care management. With the advent of dedicated ACS units or teams, this is a popular rotation to maximise the exposure to the management of critically injured patients and to learn in real time the necessary decision making skills to expedite care. ACS surgeons will also be focused on teaching relevant courses such as ATLS, DSTC, and PHTLS and provide a ready pool of trained surgeons for mass casualty events. Since the formation of trauma units precedes the development of the ACS model or care, it’s important to highlight that high level trauma care delivery remains the gold standard and traditional units (Tan Tock Seng, National University and Changi General Hospital) have significantly added to the established literature [22–25].

Singapore’s ACS systems have also driven several workflow innovations. Emergency Laparotomy Pathways (ELAPs) coordinate surgical, anaesthetic, and critical care teams around urgent laparotomy cases. Results include a reduction in time for surgery decision making and patients getting to theatre, higher consultant anaesthetist presence in OT, and an increase in geriatric assessment of patients. There were also trends towards reductions in morbidity and mortality rates and these findings were sustained over 4 years later [26, 27].

Abscess pathways have also been formalised across several institutions. These protocols expedite diagnosis, facilitate radiological or surgical drainage, and streamline admission and theatre access. The goal is to reduce unnecessary hospitalisation and preserve operative capacity for more urgent cases by diverting patients away from the ED towards elective admissions within a few days.

ACS implementation has been associated with improved clinical outcomes. In an appendicitis cohort, time to CT, surgery, operative time and LOS reduced after the implementation of an ACS service [28, 29]. Both before and after the pandemic ACS models of care adapted to provide improvements in morbidity, mortality and efficiency of care (reduction in LOS, shorter time to CT/OT) across a wide variety of conditions. Complication rates remained unchanged, indicating that care quality was preserved [30, 31].

Local data has shown significantly worse outcomes for elderly critically ill patients especially those that undergo emergency laparotomy with higher LOS, post-operative complications and mortality [32]. These findings strengthen the case for integrating geriatricians and structured post-acute enhanced recovery pathways into the ACS model, which has already begun in multiple institutions [33–35]. Table 2 provides a summary of local outcomes from ACS models of care.

Table 2.

Published Singapore ACS/ELAP outcomes and key performance indicators (2014–2025)

Study	Setting & Period	Sample (pre → post)	Key performance indicator (pre → post)	Effect
Emergency laparotomy pathway (ELAP) [26]	Single institution (2017 → 2019)	152 → 162	30-day mortality 5.3% → 3.1%	↓ mortality (NS), p = 0.40
			Clavien–Dindo IV complications 11.2% → 3.1%	↓ major complications, p < 0.01
			Cost per admission (SGD) 32 128 → 27 947	↓ cost (NS), p = 0.24
Appendicitis under ESAT (ACS model) [29]	Single institution (2014 → 2017)	192 → 179	ED referral → surgical review 127 ± 102 min → 77.8 ± 46.9 min	Faster review, p < 0.0002
			Case booking → OT 157.3 ± 209.1 min → 72.4 ± 55.2 min	Faster to theatre, p < 0.01
			Daytime operations 39.1% → 50.2%	↑ daytime surgery, p = 0.029
			Complications (CD ≥ II) 3.4% → 0.6%	↓ complications (trend), p = 0.07
ESAT consultant-led service (system-wide) [30]	Multi-centre before → after implementation	1248 → 1279	Mean LOS (days) 4.5 → 3.5	↓ LOS, p < 0.01
			In-hospital mortality 1.9% (24/1248) → 0.9% (11/1279)	↓ mortality, p = 0.03
Enhanced ACS (eACS) during COVID-19 [31]	SGH ACS vs. eACS 2020 period	–	Overall LOS ↓ by 2 days	Efficiency gain (reported)
			ED time ↓ by 46 min	Efficiency gain
			Surgery → discharge ↓ by 2.4 h	Efficiency gain

ACS:  Acute care surgery; ESAT:  Emergency surgery and trauma service; ELAP: Emergency laparotomy pathway; ED : Emergency department; OT: Operating theatre; LOS: Length of stay; CD:  Clavien–Dindo classification; NS: not significant

Overall, compared with the United States’ credential-based ACS programs, Singapore’s model more closely parallels Australia’s ASU framework, emphasising consultant of the week structures and shared emergency OT access. Unlike the UK’s NELA-driven audit system, Singapore relies on institutional governance, offering flexibility with limiting standardised data benchmarking.

Challenges to ACS in Singapore

In Singapore, ACS models have attempted to transform care for critically ill EGS and trauma patients for the past decade. Yet significant challenges remain. Workforce fatigue, registrar training gaps, inconsistent subspecialist integration, theatre bottlenecks, and the lack of credentialing continue to threaten the model’s long term sustainability.

The attending/consultant of the week model improves continuity and is relatively easy to implement within departments staffed by general or specialist surgeons. However, it concentrates workload into intense periods, particularly in smaller departments with limited consultant numbers. Surgeons are expected to manage high acuity cases with junior teams across compressed schedules, often sacrificing elective lists during that time. Without adequate recovery periods or incentives to offset this disruption, burnout becomes inevitable. For most hospitals, a full time ACS surgeon would be helpful, but it is not mandatory. Instead, the Australasian acute surgical unit model, supported by a dedicated junior team during weekday hours, remains the preferred approach for delivering focused emergency care shared amongst the department’s surgeons.

However, this does not address the original incentive that drove ACS development in the United States: a declining trauma workforce. Trauma remains one of the least sought after specialties in Singapore, and as in the USA, ACS offers a viable structure where trauma is embedded within a broader practice that includes EGS, critical care, and some elective work. Many institutions still require surgeons to commit a portion of their full time equivalent (FTE) to trauma as part of staffing rosters. By cultivating interest in ACS among early career surgeons, in the background of a senior management backed ACS model of care, the specialty remains the only realistic path to sustaining trauma coverage in the long term.

For those dedicating 0.5 or 1.0 FTE to ACS, the barriers are significant. These include limited or no access to private cases, reduced opportunities to transition to private sector practice, increased weekend and after hours responsibilities, and less prestige compared to sub specialist peers. Rather than viewing this role negatively, institutions should actively support surgeons who choose to focus on ACS. This includes formal pathways for progression, recognition, and protected time. A national ACS fellowship, structured consultant development, and subspecialty recognition by the College of Surgeons, linked to credentialing and remuneration, would strengthen long term viability.

Registrar engagement remains variable. While structured ACS rotations exist in larger centres, some hospitals still lack consistent sub specialist supervision, particularly for trauma cases. This limits exposure to high risk operative decision making and acute care skills. Embedding ACS rotations into the national residency curriculum, supported by simulation, procedural benchmarks, and defined supervision, would ensure consistent standards. Perhaps more importantly, it would garner interest in residents that a career in trauma care is a worthwhile option. In the transition from the BST-AST system to the ACGME residency model, MOH recognised the need for newly minted specialists to first consolidate general competencies before pursuing subspeciality training. This moratorium helped ensure that residents developed a broad clinical base and could safely manage emergency general surgical conditions. Embedding such generalist experience into ACS rotations reinforces the foundational ethos of ACS, that timely high quality care for critically ill patients should not depend solely on narrow specialty expertise.

Subspecialist coordination is also uneven. Many ACS cases overlap with colorectal, hepatobiliary and upper GI domains. At institutions like SGH, with strong subspecialist presence, ACS services can thrive in parallel. In most others, surgeons with narrow subspecialty training are still expected to manage broad spectrum EGS, often without escalation protocols. As generalist training declines, departments will need to build explicit rosters that balance emergency coverage with subspecialist capacity.

Critical care, a cornerstone of ACS in the US where surgeons often run the ICU, has not gained traction locally. However, there is growing interest among residents and junior consultants in managing high dependency units. Allowing ACS surgeons to oversee perioperative critical care, leading multidisciplinary rounds, directing admissions/discharges, and teaching trainees could become a key component of future ACS fellowships in Singapore.

Theatre access remains a persistent challenge. While the General Surgeons Australia (GSA) framework views protected theatre time as essential to ACS success, most local institutions share emergency lists across disciplines including orthopaedics, obstetrics, neurosurgery, and cardiothoracic surgery. This often leads to overrun sessions, delayed access, and missed opportunities for early intervention. Some centres have trialed solutions such as dedicated lists, expanded anaesthesia staffing, and pathways for early discharge of low acuity cases. However, a consistent national strategy is still lacking [36].

With the increasing organisation of services along cluster-level lines, inter hospital collaboration will be critical. Smaller hospitals without the scale for dedicated ACS units can benefit from partnerships with larger centres through shared audit platforms, protocol harmonisation and consultant backup and support. Tactical elements such as call roster structures should be designed with sustainability and cross institutional integration in mind, recognising that some solutions are best shared across clusters rather than replicated within institutions.

At present, trauma outcomes are monitored through institution contributions to the mandated National Trauma Registry. Developing an expanded national registry that integrates both trauma and emergency GS (ACS) data would enable more comprehensive outcome tracking and support multicentre research, benchmarking and policy development for the entire acute care cohort.

Finally, ACS lacks formal credentialing in Singapore. Despite its central role in every major hospital, ACS is not recognised as a subspecialty and is not tied to funding or key performance metrics. In contrast, ACS in Australia and the United States is embedded within national governance and accreditation frameworks. For Singapore to retain and grow its ACS workforce, formal recognition and system level support must follow.

Conclusion

Singapore’s adoption of ACS has improved access, efficiency, clinical outcomes and training in the care of EGS and trauma patients. To sustain these gains, national frameworks for credentialing, workforce planning, and structured training are needed [37]. Addressing ongoing challenges in trauma coverage, perioperative access, and consultant retention will be critical to securing ACS as a core part of the local surgical system. Future policy efforts should focus on establishing national credentialing, ACS fellowships and cluster-based data sharing platforms to maintain quality and sustainability. A national training roadmap for ACS would also align manpower development with system needs.

Author contributions

All authors contributed to the conception, writing, editing and details of the manuscript. They all agree with the final draft.

Funding

No funding was acquired for this project.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable

Consent for publication

Not applicable

Competing interests

The authors declare no competing interests.