The St Marys fragmentation grenade explosion

Introduction

Figure 1: Immediate area of the explosion. Patient C was sitting in the chair in the foreground, with Patient A in the chair immediately behind, while Patient B was standing behind the two. Patient D was sitting on the other side of the bench, opposite Patient C. The pallet to the left carried 1000 live grenades and was 1.85 m from the grenade burst point. Forty-eight grenades were damaged in the explosion and represented an explosive hazard during recovery operations.
Photograph courtesy of the New South Wales Police.

The first ambulances arrived at 8:41, 8:44 and 8:47. The four injured workers were extricated from the factory building to an adjacent courtyard by other employees and ambulance personnel. NRMA CareFlight, a Bell 412 HP helicopter emergency medical service (HEMS) with a physician on board, was placed on standby at 8:45 and dispatched at 8:50, landing at the site at 9:06.

Two patients were transported by air to a trauma centre with full cardiothoracic facilities about 24 km (10 minutes' flying time) from the factory. Access to this centre by road would have encountered peak hour traffic flowing into Sydney via the major western arterial road routes. Two patients were transported by road to a local trauma centre (10 minutes' travelling time) which has limited cardiothoracic surgical facilities.  

Patient records

Patient A

On arrival at hospital, Patient A had a heart rate of 100/min, systolic blood pressure, 118 mmHg; haemoglobin level, 79 g/L (normal range, 115-165 g/L); pH, 7.29 (normal range, 7.35-7.45); PO₂, 518 mmHg (normal range, 75-100 mmHg); PCO₂, 30 mmHg (normal range, 35-45 mmHg); HCO₃, 14 mmol/L (normal range, 22-26 mmol/L); and serum lactate, 3.04 mmol/L (normal range, 0.63-2.44 mmol/L). She was taken to theatre for thoracotomy and laparotomy, enucleation of left orbit, amputation of right ring and little fingers, debridement of right forearm and thigh, with internal fixation of her right forearm fractures. By the end of her first theatre session she had received (in addition to her prehospital fluids) 6.5 L of polygeline, 4 L of crystalloid, 24 units of packed red blood cells, 8 units of frozen plasma and 6 units of platelets.

Patient A's injuries were:

• Multiple puncture wounds to the face, neck, chest and abdomen
• Singed hair and eyebrows
• Grenade fragments in the right maxillary antrum and right side of the nasopharynx
• Multiple puncture wounds to the left eye
• Bilateral perforated tympanic membranes
• Multiple fractured teeth
• Subtotal traumatic mastectomies (Figure 2a)
• Bilateral haemothoraces, with contusions of the right middle lobe and both lower lobes of the lungs
• Perforation of the right ventricle and apex of the heart, with a 250 mL pericardial haematoma
• Perforations of the stomach, left lobe of the liver, and splenic flexure of the colon
• Haematomas of the head of the pancreas, lesser omentum and left perinephric region
• Comminuted compound fracture of the right radius and ulna, with major soft tissue disruption to the dorsal surface of the right forearm (Figure 2b)
• Subtotal amputation of the right ring and little fingers
• A large skin and muscle defect to the anterior aspect of the right thigh (Figure 2c).

After her initial surgery, Patient A required mechanically assisted ventilation for 11 days and underwent five additional operative procedures during her initial 39 days in hospital. In the next year she underwent another five operative procedures, with a further five reconstructive procedures scheduled for the following year.  

Patient B

On arrival at hospital, Patient B had a heart rate of 88/min; systolic blood pressure, 140 mmHg; Glasgow coma score, 15; haemoglobin level, 83 g/L; pH, 7.30; PO₂, 331 mmHg; PCO₂, 36.6 mmHg; HCO₃, 17.8 mmol/L; and base excess, - 7.2 (normal range, - 3 to 3). Patient B was taken to theatre for laparotomy and cholecystectomy. Her injuries were:

• Multiple puncture wounds to the face, neck, thorax and abdomen
• Forehead laceration and fractured nose
• Grenade fragments in the ethmoid and sphenoid sinuses, plus a fragment in the occipital lobe of the brain.
• Contusion of the lower lobe of the left lung
• Multiple perforations of the liver and gallbladder
• Lacerated right kidney and retroperitoneal haematoma
• Fragments adjacent to the abdominal aorta and the right L3 nerve root
• Delayed third-nerve palsy.

She was discharged from intensive care after 1.5 days and discharged home after 18 days. She underwent six subsequent day procedures to repair soft tissue injuries and extract fragments.  

Patient C

On arrival at hospital, Patient C's heart rate was 83/min; systolic blood pressure, 151 mmHg; Glasgow coma score, 14; and haemoglobin level, 125 g/L. Her injuries were:

• Multiple small puncture wounds to the left upper limb and left side of the thorax
• A chin laceration and left periorbital haematoma; there were no perforations of the tympanic membranes
• A closed fracture of the left ulna
• A small left retinal tear and preretinal haematoma
• A fragment in the medial rectus of the left orbit.

Patient C was discharged home after two days.  

Patient D

• Multiple fragment wounds to the right side of the face, neck, thorax and upper limb, including an intracapsular fragment in the right shoulder joint and a 4 cm scalp laceration
• Bilateral perforations of the tympanic membranes
• Right pneumothorax requiring drainage with an intercostal catheter, plus pulmonary contusions of the right mid and lower zones.

She was discharged after seven days and subsequently underwent two outpatient procedures to extract fragments.  

Discussion

The grenade exploded on a bench top, which directed most of the blast and fragments onto the upper torso of the victims, but it also blew a hole in the bench top, producing the wound to the right thigh of patient A.

Any bomb or blast scene should always be considered dangerous until declared safe from the risk of secondary explosion by appropriate technical personnel. Specialist bomb disposal personnel were not part of the initial response to the St Marys incident, which contributed to the delayed recognition of a potential secondary explosion hazard from 48 damaged grenades at the site.

The size and shape of modern military weapons often belie their wounding potential. Explosive devices may contain fuse mechanisms that detonate in response to stimuli other than that of direct impact. The bodies of victims may conceivably hold unexploded devices that pose a threat to rescue, medical and mortuary personnel.^11,12 Major injuries and deaths occurred during the Gulf War among medical and service personnel handling souvenired battlefield ordnance.¹³

Injury from military weapons is uncommon in Australia. Army ammunition technical officers can provide expert advice on the composition and function of a particular device. This information is vital in the assessment of individuals wearing body armour, or who have been potentially exposed to either radiolucent fragments or items of ordnance which have become airborne.^11,12

Early on-site specialist technical advice is critical to safe operations at the scene of an urban explosion.

Helicopter emergency medical services have been used in the primary and secondary transport of blast victims.^14,15 In this incident the HEMS rapidly provided a doctor on-site to assist in trauma triage. This allowed patients to be referred immediately for specialist surgical care, while dispersing casualties over a wider network of receiving hospitals (thus Patient A and Patient B were sent to different hospitals so that both could receive immediate surgical treatment; this would not have occurred under ambulance protocols). In addition, on-site medical care went beyond the scope of paramedic protocols¹⁶ (e.g., in performing a relaxant-assisted intubation and giving a blood transfusion).

The NSW Ambulance Service Disaster Plan (December 1995) precludes the immediate dispatch of physician-staffed helicopter emergency medical services to potential multicasualty incidents. This may introduce avoidable delays in delivering seriously injured patients to definitive surgical care, especially in incidents geographically removed from designated trauma centres.  

Acknowledgement

References

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(Received 17 Jul 1996, accepted 18 Feb 1997)