A day like no other: the Las Vegas mass shooting lessons from America’s largest mass casualty event

Abstract

The October 1, 2017, mass shooting at the Route 91 Harvest Festival in Las Vegas, Nevada, represented the largest mass casualty event in modern US history, fundamentally challenging traditional assumptions about hospital disaster response. This review analyzes critical aspects of the hospital response, with particular emphasis on throughput optimization, resource management, and adaptation of conventional trauma protocols. Through detailed examination of hospital responses across multiple facilities, this paper identifies three key paradigm shifts: (1) the primacy of patient throughput over traditional surge capacity metrics, (2) the emergence of combat-style triage protocols in civilian settings, and (3) the development of novel resource management strategies. Key findings demonstrate that traditional surge planning assumptions proved inadequate when faced with hundreds of critically injured patients arriving simultaneously without prehospital triage. The incident forced rapid adaptation of military-style triage protocols and highlighted the critical importance of inter-facility resource sharing networks. These lessons continue to influence emergency preparedness and provide a framework for hospitals worldwide to enhance their mass casualty response capabilities.

Introduction

Context and significance

Clark County, Nevada, home to Las Vegas, is a unique healthcare environment.^{1 2} Despite being geographically isolated—the next closest metropolitan area is San Bernardino, California, approximately 183 miles away—the region hosts over 43 million visitors annually.¹ The healthcare system consists predominantly of private facilities, including a mix of for-profit and non-profit institutions.¹ Clark County has three trauma centers accredited by the American College of Surgeons’ Committee on Trauma²: one Level I and one Level II center near the Las Vegas tourist corridor, and a Level III center located in Henderson. Prior to October 2017, the region had extensive experience managing large-scale events, including New Year’s Eve celebrations drawing 250,000+ attendees and conventions hosting over 180,000 participants.¹ However, no previous event had tested the healthcare system’s capacity like the events of October 1, 2017.

Event overview

At 10:05 p.m. on October 1, 2017, a gunman opened fire on approximately 22,000 attendees at the Route 91 Harvest Festival, an outdoor country music concert.¹ From a position on the 32nd floor of the Mandalay Bay Resort, 350 yards from the venue, the shooter fired over 1000 rounds in approximately 15 min using rifles modified with bump-stock accessories to achieve near-automatic fire rates.¹ The attack resulted in 31 immediate fatalities and 26 individuals who succumbed to their injuries within the first 24 hours at area hospitals. In total, over 800 people were injured, with 413 victims sustaining gunshot wounds requiring immediate treatment.¹

The response diverged significantly from traditional mass casualty protocols. First responder access was severely limited by ongoing gunfire, forcing emergency services to remain at a distance.¹ This created an unprecedented scenario where approximately 800 injured victims coordinated their own evacuation and hospital transport.¹ Using smartphone mapping applications, victims self-transported or used ride-sharing services to reach the nearest hospitals.¹ The crowd dispersed across four square miles of urban Las Vegas, seeking shelter in hotels, churches, stores, and airport facilities.¹

Adding to the complexity of the response, injured victims began arriving at local hospitals while the shooting was still ongoing.¹ This concurrent presentation of patients during an active incident created unprecedented challenges for hospital staff.¹ Without knowledge of whether this was a lone gunman or coordinated terrorist attack, or whether the casualties were from a single or multiple incidents, staff had to manage their immediate clinical response while dealing with significant uncertainty about the scope and scale of what was unfolding.¹ Hospital teams had no reliable way to estimate the total number of patients they would receive or predict when the surge would slow.¹ This uncertainty about the nature and extent of the threat, combined with the continuous arrival of critically injured patients, created an environment of heightened tension and fear that staff had to manage while delivering care.¹

This incident fundamentally challenged three core assumptions of mass casualty response: that patients would arrive via ambulance with prehospital care and triage, that patient distribution would be coordinated across facilities (figure 1), and that traditional surge capacity metrics would be the primary measure of hospital readiness.¹ The combination of active shooter dynamics, widespread scene dispersal, and patient self-transport created unique challenges that continue to influence mass casualty planning.¹

Figure 1.

Patient distribution by hospital. Original PowerPoint slide.

Traditional surge planning versus reality

Why throughput became the critical metric

For years, hospitals had based their mass casualty preparedness on achieving a surge capacity of 20 percent above their licensed bed capacity.¹ However, the Las Vegas shooting demonstrated that this metric was inadequate for modern mass casualty events.¹ The majority of patients arriving at hospitals required immediate surgical intervention to control hemorrhaging, making the speed of moving patients through the system, rather than the number of available beds, the determining factor in saving lives.¹

Hospitals discovered that traditional surge capacity planning failed to account for several critical factors.¹ First, the assumption that Emergency Medical Services (EMS) would provide field triage and coordinate patient distribution proved invalid when hundreds of critically injured patients self-transported to the nearest facilities.¹ One hospital reported a line of private vehicles more than a quarter mile long waiting to access their emergency department.¹ Second, patients arrived without prehospital care or advance notification, requiring immediate triage and intervention on arrival.¹ Finally, the volume and acuity of patients meant that emergency departments needed to function more as throughput nodes than treatment areas.¹

Key bottlenecks

Several critical bottlenecks emerged that traditional surge planning had not adequately been addressed¹:

1. Patient registration: Electronic health record systems and registration processes designed for normal operations proved too time-consuming for the volume and pace of patient arrivals.¹ Many critical patients went directly to surgery without formal registration, creating downstream documentation challenges.¹

2. Operating room capacity: The limiting factor was not bed space but the ability to rapidly move patients requiring immediate surgery through available operating rooms (ORs).¹ One hospital alone treated 124 gunshot wounds in less than 24 hours.¹

3. Environmental services: The rapid turnover of trauma bays, operating rooms, and patient care areas became critical to maintaining patient flow.¹ Environmental services staff emerged as key enablers of hospital throughput, with their ability to quickly clean and prepare spaces for the next patients proving as important as clinical capacity.¹

4. Supply chain management: Traditional par levels for critical supplies proved inadequate for the pace of consumption.¹ Items such as chest tubes, rapid sequence intubation medications, and even basic supplies like clean linens were depleted faster than normal resupply processes could accommodate.¹

The experience demonstrated that future mass casualty planning must focus on optimizing system throughput rather than static capacity metrics.¹ This requires attention to the entire patient care continuum, from initial arrival through definitive treatment, with particular emphasis on removing bottlenecks that could impede rapid patient movement through the healthcare continuum.¹

Combat-style triage systems

Traditional (start) triage versus what happened

The Las Vegas mass shooting fundamentally challenged traditional civilian triage protocols.¹ Simple Triage and Rapid Treatment (START), the most common triage system in the USA, assumes first responders will conduct initial patient sorting before hospital arrival.¹ However, during the October 1 incident, this system proved inadequate as patients arrived at hospitals without prehospital triage, many via private vehicles and rideshare services.¹

The response that emerged more closely resembled military mass casualty protocols, particularly the principle articulated in military doctrine that triage must be “the most effective means for establishing order in a chaotic environment and the best method for providing the greatest benefit to the greatest number of patients within the limitations of time, distance, and capability.”^{2 3}

Immediate OR for hemorrhage control

The most successful triage protocol that materialized during the incident reflected military combat surgery principles^{2 3}:

• Initial rapid evaluation by a surgeon at the emergency department entrance.

• Immediate identification of patients requiring surgical hemorrhage control.

• Direct routing to operating rooms for damage control surgery.

• Delayed definitive repairs until after initial stabilization.

This approach proved more effective than traditional START triage because it prioritized the most time-critical interventions.³ Like military “on-table triage,” decisions about surgical priorities remained fluid, with resources constantly redirected to save the most lives possible.³ One hospital rapidly treated over 100 gunshot wounds using this modified military approach.³

Specialty-specific cohorting

A key innovation that emerged was the creation of specialty-specific treatment zones, similar to military forward combat hospitals.¹ Patients were sorted based on their most serious injury:

• Patients with thoracic injuries were cohorted to areas where cardiothoracic surgery teams were staged.

• Neurological cases were directed to dedicated spaces with neurosurgical teams.

• Orthopedic injuries were grouped together in separate areas.

• Patients with isolated extremity wounds were staged in designated waiting areas for delayed treatment.

This specialty-specific cohorting allowed for more efficient resource utilization and enabled surgical teams to rapidly move from one patient to the next within their specialty.¹ Importantly, like military triage, it remained a dynamic process—patients could be re-categorized based on changing conditions or resource availability.¹ Due to the mechanism of injury, there were no identified cases of individuals with multiple gunshot wounds.

The experience demonstrated that civilian hospitals facing mass casualty events may need to adopt military-style triage principles that emphasize rapid identification of immediate surgical needs and dynamic resource allocation over traditional START categorization.¹ This is particularly true when patients arrive without prehospital triage or treatment.¹

Resource management

Critical supply depletion patterns

The Las Vegas mass shooting revealed unexpected patterns in how critical supplies were depleted during a mass casualty event.¹ Hospitals discovered that their traditional 96-hour sustainment calculations, based on normal patient flow patterns, proved insufficient.¹ Items that were expected to last 96 hours were depleted within 2–4 hours due to the intense pace of trauma care.¹

Critical shortages emerged in several key areas¹

• Basic medical supplies such as chest tubes, endotracheal tubes, and rapid sequence intubation medications.

• Environmental service supplies, particularly clean linens which required replacement 4–6 times per hour per bed.

• Simple items not typically considered critical, such as ball-point pens, triage tags, and other documentation materials which became contaminated and required disposal.

• Intravenos fluids, with hospitals requiring immediate resupply from unaffected facilities.

Surprisingly, blood product shortages were never incurred, despite the large number of casualties requiring immediate hemorrhage control.¹ A detailed study of blood component use revealed that nearly 500 blood components were transfused during the first 24 hours in a red blood cell-to-plasma-to-platelet ratio of 1:0.54:0.81.⁴ Public citizens donated almost 800 units of blood immediately after the shooting, with over 17% of the donated blood going unused.⁴ This success in blood product management contrasts with traditional mass casualty planning assumptions and reflects both robust pre-existing blood bank inventory and effective regional blood center coordination.⁴ The experience demonstrated that maintenance of adequate blood supplies during mass casualty events is achievable with proper regional coordination and established blood center networks.⁴

OR turnover optimization

Operating room management became a critical focus, with hospitals developing several innovative approaches¹:

• Implementation of damage control surgery principles—performing only essential life-saving procedures initially.

• Creation of specialty-specific OR teams that could rapidly move between similar cases.

• Establishing expedited cleaning and sterilization protocols to minimize room turnover time.

• Coordinating with environmental services to ensure rapid terminal cleaning between cases.

One particularly successful approach involved¹:

1. EDs were used as rapid pre-op stations, only establishing definitive airway management, vascular access and applying tourniquets.

2. Initial surgery focused solely on hemorrhage control.

3. Temporary closure with plans for definitive repair later.

4. Immediate room turnover for the next critical case.

5. Return to OR for definitive procedures once the initial surge has subsided.

Inter-agency resource sharing

The event demonstrated the importance of robust inter-agency cooperation.¹ Key aspects included the following:

• Rapid activation of mutual aid agreements between facilities, sharing personnel, supplies and immediately accepting patients for hospital decompression.

• Long-term acute care hospitals providing supplies to affected acute care facilities.

• Sharing of specialized surgical teams between facilities when patient transport was not feasible.

• Use of fire department personnel to help extricate patients from private vehicles as they arrived at hospitals.

• Development of informal supply and personnel sharing networks proved more efficient than traditional supply chains.

The most effective resource sharing occurred through direct facility-to-facility communication, bypassing normal bureaucratic channels to meet immediate needs.¹ Emergency room nurse managers were able to request and receive supplies and personnel from other facilities. Staff members used their private vehicles to deliver needed items.¹

Conclusion

The October 1 mass casualty incident fundamentally transformed how we approach mass casualty event management in Southern Nevada and beyond. The lessons learned have led to significant systematic changes, including the development of the Hospital Area Command (HAC) collaboration system⁵ and the implementation of real-time system status watchboards that monitor both emergency department and overall facility status across the region. The HAC system enables hospitals to request emergency fire personnel and paramedics through 911 during mass casualty incidents, providing crucial support for patient extrication, initial triage, vascular access, and definitive airway management as self-transported patients arrive at emergency departments. This innovative program addresses a critical gap identified during the October 1 response, where hospitals were overwhelmed by self-transported patients arriving without prehospital care.

Beyond personnel support, the incident revealed major limitations in existing hospital capacity tracking systems. Commonly employed computer systems that merely track occupied or empty hospital beds proved essentially useless during sudden-impact mass casualty events. While these automated systems can easily capture bed availability through computer Application Programming Interfaces (APIs) without human input, they fail to reflect the critical factors that actually determine a hospital’s capacity to receive and treat mass casualty patients, namely, available human resources, availability of specialty practitioners, and necessary supplies. The watchboards developed after October 1 address these limitations by incorporating real-time data about facility throughput capabilities and resource availability, providing unprecedented situational awareness during mass casualty events and facilitating more effective resource allocation and patient distribution.

The introduction of standardized communication protocols and coordination between hospitals, fire departments, and emergency services has created a more resilient and responsive healthcare system. This evolution in mass casualty response, born from the lessons of October 1, demonstrates how healthcare systems can adapt and improve after catastrophic events. The development of these new protocols and systems serves as a model for other metropolitan areas seeking to enhance their mass casualty response capabilities.

Future refinements to these systems will likely focus on further integration of technology and real-time data sharing capabilities,⁴ but the fundamental paradigm shifts in patient throughput, resource management, and inter-facility coordination established in the aftermath of this incident will continue to guide mass casualty response planning for years to come.^{1 5}

Ethics statements

Patient consent for publication

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Ethics approval

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