Destructive disasters, trauma, crush syndrome, and beyond

Abstract

Orthopedic injuries, especially fractures of long bones as well as multiple fractures and comminuted fractures, are very common after destructive disasters (e.g., earthquakes, wars, and hurricanes). Another frequent problem is traumatic rhabdomyolysis, which may result in crush syndrome, the second most frequent cause of death after direct traumatic impact following earthquakes. To improve outcomes, interventions should be initiated even before extrication of the victims, which include maintenance of airway patency and spine stabilization, stopping traumatic bleeding by any means, and initiating fluid resuscitation. On-site amputations have been extensively debated to liberate the victims if the release of trapped limbs is impossible. Early after the rescue, a primary survey and triage are performed, a fluid resuscitation policy is planned, complications are treated, the wounds are decontaminated, and the victim is transported to specialized hospitals. A triage and primary survey are also performed at admission to the hospitals, which are followed by a secondary survey, physical, laboratory, and imaging examinations. Washing and cleaning of the soft-tissue injuries and debridement in open, necrotic wounds are vital. Applications of fasciotomies and amputations are controversial since they are associated with both benefits and serious complications; therefore, clear indications should be defined. Crush syndrome has been described as the presence of systemic manifestations following traumatic rhabdomyolysis, the most important component of which is acute kidney injury that may contribute to fatal hyperkalemia. The overall mortality rate is around 20% in crushed patients, which underlines the importance of prevention. Treatment includes maintaining of fluid electrolyte and acid–base balance, application of dialysis, and also prevention and treatment of complications. The principles and practices in disaster medicine may differ from those applied in routine practice; therefore, organizing repeated training courses may be helpful to provide the most effective healthcare and to save as many lives as possible after mass disasters.

Introduction

Disasters are “natural” or “man-made” events, causing “serious disruptions of the functioning of a society resulting in widespread human, material, economical, or environmental losses.”¹ In the case of a “mass disaster,” the number of victims is enormous, the infrastructural damage is extensive, and external help is needed.² Disasters may also be classified as “destructive (characterized by physical damage to buildings and/or infrastructure; e.g., wars, earthquakes, hurricanes)” or “non-destructive,” which may result in extensive deaths but with no structural damage (e.g., the coronavirus disease-2019 pandemic).^3,4 The most important “destructive” disasters for Turkey are earthquakes; therefore, we will focus on these disasters in this review article. Earthquakes drew the attention of the medical community more than ever after the 2 recent very severe quakes (registered 7.7 and 7.6 on the Richter’s scale). Disasters hit the south-eastern region of the country 2 times within a 13-hour period within the same day (February 6, 2023), causing more than 50 000 deaths and injuring 107 000 people.⁵

In addition to economical and social problems, disasters cause extensive psychological and/or physical health problems, either within the disaster period or long after disasters.⁶ In this spectrum, trauma and its consequences deserve special attention because they may result in extensive morbidity and mortality both directly and also indirectly. This publication aims to describe the spectrum, features, treatment possibilities, and prevention of trauma-related problems after destructive disasters.

An overview of injuries after earthquakes

Injuries after earthquakes may show significant differences depending on the building characteristics of the affected region, the efficacy of rescue activities, and registration accuracy. Vulnerable populations (e.g., those with low socioeconomic status, members of minority, ethnic groups, those who are older or frail, women, children, and those with noncommunicable diseases) are especially at high risk of being injured.⁷ Overall, disaster-related injuries may be classified as non-orthopedic vs. orthopedic, major vs. minor, simple vs. comminuted and include only 1 vs. more than 1 portion of the body.⁸ A review article focused on earthquakes in developing countries revealed that, considering the orthopedic injuries, fractures were responsible for the vast majority (65%) of the problems and were mostly confined to the tibia/fibula (27%), femur (17%), and foot/ankle (16%).⁸ Overall, in 42% of the cases, there were multiple fractures, 22% of which were open and 16% were comminuted.⁸ In the overall trauma pattern, fractures were followed by crush injury (13%), compartment syndrome (7.6%), and major soft-tissue injury (7.3%).⁸ Non-orthopedic injuries (confined to the head, chest, and/or abdomen) accounted for 13% of the injuries, all of which were associated with unfavorable outcomes.⁸ Association of thoracic and abdominal injuries with a high risk of mortality was also reported after the Marmara earthquake among 639 patients with crush syndrome.⁹

Interventions early after disaster

Disaster-related problems may be seen at the disaster field, during patient transfer, and at the treatment centers. Therefore, interventions will be described separately in these particular locations.

Interventions at the disaster field

Thirteen to 40% of early deaths can be avoided by simple, vigilant medical, and surgical interventions such as proper airway control, prevention of blood loss, fracture stabilization, fluid resuscitation, and control of hypothermia.¹⁰ Therefore, healthcare personnel should be familiar with life support for entrapped/rescued victims, polytrauma, crush injuries, and fluid resuscitation. The type and extent of treatment at the disaster field depends upon the severity and timing of the disaster, self-safety concerns, availability and/or efficacy of the collaborators and/or rescue team members, and the professional knowledge, capacity, and experience of the healthcare provider.

Rescue of the victim—early interventions

Early management at the site—if possible and safe—should be initiated even before the extrication of the victim.¹¹ The most important early interventions are maintenance of airway patency, spine stabilization, and also stopping traumatic bleeding. On-site amputationshave been debated extensively to liberate the victims, if release of a trapped limb is impossible and there is a need for an urgent extrication, such as the very high risk of collapse of the building, which may result in death of the victim and the rescuer.^12,13 An as distal as possible guillotine amputation in addition to applying a tourniquet upstream the wound to prevent excessive bleeding has been suggested for this procedure.² On-site amputation is extremely risky, with very high rates of morbidity and mortality, and should be applied only with very strict criteria.

Early after the rescue, a primary survey and triage should be performed, wounds should be decontaminated, fluid resuscitation policy should be planned, and other interventions should be applied before transport of the victim.² Regarding treatment priorities, some minor problems (e.g., small, closed finger fractures) may be postponed, whereas some other cases represent a medical emergency (i.e., open fractures of large bones, which may cause vessel injuries and profuse bleeding).

Reperfusion of the crushed extremity following extrication may lead to the release of myoglobin and other toxic metabolites into the systemic circulation, contributing to the pathogenesis of crush syndrome,¹⁴ which will be described under the heading Crush Syndrome in this review. Some authors suggest the application of a proximal tourniquet to the injured extremity at the earliest convenience to prevent crush syndrome.¹⁵ However, prolonged application of proximally placed tourniquets may unnecessarily expose the patient to increased risk of palsy, myonecrosis, thrombosis, rigor, abscess, blisters, abrasions, contusions, and pinching.² Also, they may increase the risk of myoglobinuria and acute kidney injury (AKI) once the tourniquet is released. Therefore, tourniquets should not be applied to prevent crush syndrome; however, they should be used only as a last resort for stopping bleeding that appears uncontrollable by either direct pressure or other hemostatic measures.^16,17 Patients in whom tourniquet application is unavoidable should receive evacuation priority. Tourniquets should be removed at the earliest convenience to limit tissue ischemia and the risk of limb loss.

Fluid resuscitation

Since early fluid resuscitation is vital to prevent crush-related AKI, a large bore venous access should be placed in any limb, even when the victim is still entrapped, and intravenous isotonic saline at a rate of 1000 mL/h should be initiated.⁴ If intravenous access cannot be achieved, intraosseous infusion is an alternative,^18,19 although this intervention is hard to apply in disaster field conditions. If even intraosseous access is impossible, then hypodermoclysis (subcutaneous infusion of isotonic fluids) at a rate of approximately 1 mL/min may be considered as a last resort. By this route, fluids may be given only up to 3 L/day; therefore, it is not the ideal route when large volumes of fluids should be given. Patients with skin or bleeding disorders or peripheral edema are not appropriate candidates for hypodermoclysis.²⁰ In alert patients with no risk of intraabdominal pathology and no need for imminent anesthesia, oral rehydration may be tried as well for fluid resuscitation; however, the exclusion of these possibilities may be problematic, especially in destructive disasters.²¹

Fluids should be continued during extrication, and the quantity to be administered during rescue should be adapted depending on the demographic features, ambient temperature, amount of overall estimated fluid losses, time spent under the rubble, access to drinking water, and the practical possibility of frequent reassessment in determining ongoing fluid requirements (Figure 1).²

Figure 1.

Fluid administration policy in crush victims following mass disasters. Large volumes of fluid may be sequestrated in the compressed muscles, resulting in compartment syndrome, hypovolemia, and hypoperfusion of the kidneys, which may play a role in pathogenesis of AKI. This problem can be prevented by early and energetic fluid administration. Fluid administration should begin even before extricating the victim (A). If this is not possible, however, fluids should be initiated as soon as the victim is rescued (B). Volume of fluids should be individualized, considering the timing of the rescue procedure, several demographic and medical parameters, and the possibility to close follow-up of the victims (please see the text for details). AKI, acute kidney injury; IV, intravenous. (adapted with permission from Reference 2).

Correction of hypothermia and other life-threatening complications

In disasters, which occur during the winters, correcting hypothermia is vital since any decrease in temperature below 35^oC is a poor prognostic sign.²² Hypothermia should be avoided with space blankets, if available. After extrication, hypothermia should be treated as an emergency. Wet clothes should be removed, warmed crystalloids (42°C) should be infused, and external warming (e.g., by placing blankets below and above the patient) should be performed.²²

Other life-threatening complications (e.g., respiratory distress, hypotension, hypertension, myocardial ischemia and infarction, cardiac failure, open fractures, and contaminated wounds) should be treated accordingly.²

Transport of the victims

Once stabilized, the patient should be transported from the disaster field at the earliest convenience. Patients with thoracic, abdominal, or head trauma should be referred to specialized hospitals.⁹

The time that will be spent for performing minor procedures such as splinting of minor fractures and bandaging of wounds should be weighed against the advantages of transporting the patient immediately to a functional hospital. If transport times are short, prolongation of field or field hospital stay should be avoided. During transport, measures should be taken for full spinal immobilization in patients with spinal trauma. In major disaster conditions, transportation may not always be possible,¹⁴ necessitating the institution of therapy on site in spite of limited resources.

Interventions at the hospital setting

Meeting and evaluating the patient

For patients arriving at the hospital, the first thing to do is triage. The triage in the disaster area should be renewed and located close to the treatment area. Treatment prioritization should be decided considering the condition of the patient.² In order to prevent chaos and confusion in disaster circumstances, triage priorities are encoded by colors, i.e., green, yellow, red, gray, and black. The process should be updated hourly when necessary.²

Primary survey, a systematic and serial evaluation to control the vital functions of a seriously injured patient, should be completed quickly in patients placed in appropriate areas by triage. Maintenance of spine stabilization is of vital importance. A primary survey should be followed by a secondary examination in stabilized patients. The secondary survey includes history, physical, laboratory, and radiological examinations. The brief medical information of the patient should include identification information, mechanisms of trauma, time spent under the rubble, and other important information.

The physical examination should be in the form of a more detailed evaluation, revealing conditions that cannot be detected at a primary survey. Laboratory examinations should include determining blood type and count and evaluating biochemical data, including electrolytes and blood gas analysis. Focused Assessment with Sonography in Trauma is recommended for radiological examinations.²³ In addition, x-ray is recommended for patients with isolated extremity injuries, and whole-body computerized tomography is recommended for patients with complex and multiple injuries.^23,24

Treatment of surgical and medical emergencies

Any major bleeding should be stopped by any means (applying direct pressure on the bleeding site, stapling, or suturing) to achieve proper hemostasis, and blood transfusion should be initiated in the victims with severe anemia or evidence of severe blood loss. If transfusion is impossible and the patient is complicated by hypotension or shock, blood volume should be replaced by crystalloids or colloids. However, it should be considered that blood transfusion is a temporary measure, and mostly a surgical procedure is needed to stop bleeding in a hypotensive trauma patient.

Hypovolemia is the main cause of death in seriously injured patients; therefore, hemodynamic resuscitation aiming to restore intravascular volume is the primary goal in patients in the hospital.²⁵ Crystalloids and colloids may be used for hypovolemia, and 0.9% isotonic NaCl is recommended as the first choice.²⁶ Patients with crush injuries are predisposed to hyperkalemia; therefore, the type of the fluid in patients who had applied fluids before hospital admission should be checked at admission, and the fluids containing potassium should be stopped immediately. In patients with crush injuries, hyperkalemia may occur without the development of AKI; therefore, both laboratory and electrocardiogram monitoring should be performed.²⁷ Urine output also should be closely monitored in these patients, and a catheter should be inserted immediately, unless contraindicated.

Any life-threatening complication (e.g., myocardial ischemia, heart failure, respiratory failure) should be treated accordingly,² and consultations with relevant experts should be organized.

Treatment of soft-tissue injuries

Soft-tissue injuries after earthquakes should be considered dirty due to dust-soil contamination. Therefore, it should be washed with water, isotonic solutions, and, if necessary, bactericidal agents.² In patients arriving at the hospital, every wound should be considered infected. Streptococcus, Staphylococcus, and anaerobic organisms are most commonly seen in crush wounds, and beta-lactam/beta-lactamase inhibitors are preferred for empirical therapy. Cefazolin, a first-generation cephalosporin effective against gram-positive cocci and some gram-negative bacilli, is beneficial in most crush patients. Aminoglycoside is often recommended for the treatment of gram-negative bacilli encountered in abdominal injuries and severe open fractures, but it is nephrotoxic. Therefore, ciprofloxacin can be given by adjusting the dose according to kidney function. In addition, drugs that can be administered once a day and have similar efficacy (for example, ceftriaxone) may be preferred due to the possibility of difficulties in drug supply and also increased frequency of non-adherence by the patients. Open wounds may be complicated by Clostridium spp. and Clostridium tetani, especially if treatment is delayed.² Therefore, tetanus toxoid or immunoglobulin should be administered according to the patient's tetanus vaccination history and according to the tetanus predisposition of the wounds.²⁸

Appropriate management of the wounds is vital. Until debridement conditions are achieved, the wound should be washed with 3 to 12 L of isotonic fluid and dressed with wet gauze to minimize wound contamination. All wounds closed by primary suturing or suspected of infection should be checked and sutures removed. Crepitation, erythema, and swelling, which are signs of infection in the tissue, should be evaluated carefully.²⁹ Debridement should be performed in open, necrotic wounds and open fractures, and cultures should be taken before starting antibiotic therapy. Patients who decide to undergo debridement should be considered as surgical emergencies. Debridement should be performed under the optimal conditions, with adequate analgesia and sedation. The goal of debridement should be to remove dead and contaminated tissue and leave enough viable tissue to allow regeneration. Debridement should be performed as a deep tissue debridement, including muscle and bone, and should be checked every 24-48 hours and repeated as necessary.²⁸ Incisions in the extremity should be on the long axis of the limb. If it is necessary to pass through the joint, the joint area should be crossed. The wound should be excised according to the layers from the surface to the deep. Scalpel is preferred instead of an electrocautery, and a tourniquet should not be used unless strictly necessary.²⁹

The skin is a highly tolerant tissue and has a good blood supply; therefore, some suspicious (not confirmed to be necrotic) tissue may be left, which may be useful in covering. If subcutaneous adipose tissue is necrotic and contaminated, it should be removed. If the fascia is shiny and clean, it can be left, but if it is bad-looking, gray, and irregular, it should be removed as it may lead to necrotizing fasciitis.²⁹ The tolerance of muscle tissue to necrosis is very low, and debridement should be continued until all infected areas are removed.²⁹ Bone tissues and joint fragments should be preserved as much as possible. During debridement, it is recommended to use low-pressure instead of high-pressure pulsative flushing during debridement.

Especially during the last decade, earthquakes caused the highest rate of deaths due to head, chest, and abdominal cavity injuries among those buried under the rubble.²⁹ For this reason, physicians who undertake the treatment of patients under the rubble are often faced with large amounts of musculoskeletal injuries due to collapsed structures. In these patients, who mostly have multiple injuries, DCO may be an appropriate approach at the first stage.³⁰ However, in recent years, “early total care” (ETC) has come to the fore instead of DCO.³⁰ By means of this approach, it is aimed to fix the fractures with temporary external fixators and to reduce the negative effects of effort, time, and blood loss used for definitive surgery.³⁰ However, these 2 approaches may not be sufficient for an extremity that has been under debris for a long time. Amputations can be considered as life-saving procedures instead of fixation of the extremity in cases where the extremity is left under rubble for a long time and in cases such as severe damage, irreparable vascular damage, or subtotal amputation.²⁵

Orthopedic interventions in disaster injuries

In patients with no possibility of amputation, the first goal is stabilization of the extremity, independent of damage-controlled orthopedics (DCO) or ETC approaches.²⁵ Earthquake-induced crush injuries are high-energy injuries. Therefore, open and comminuted fractures are common. External fixation is usually the first choice in this type of fracture. This method, which provides rapid fixation of the extremity as well as protecting the circulation and controlling the pain, can also be an extremity-saving and life-saving tool for the patient. External fixators have advantages such as being easy and fast to be applied in processes such as earthquakes, where optimal conditions cannot be met. They also carry the advantage of not causing additional damage due to bridging the injury area and being applicable in almost all long bone fractures. However, there are also some negative aspects of this procedure, such as pin tract infections, the possibility of loosening in long-term use, and blocking the tissue coverage procedures. The use of external fixators for DCO has proven to be a successful method in the acute treatment of bone fractures in complex or severely injured patients in disaster situations such as wartime and earthquakes.³⁰

Fasciotomies

Application of fasciotomies is controversial in disaster victims because they are associated with both advantages and disadvantages (Table 1).^9,31-38

Table 1.

Advantages and Disadvantages of Fasciotomies in Disaster Crush Victims

Advantages	Disadvantages
Decreased intracompartmental pressure may facilitate improvement in muscle injury and decrease necrotic muscle mass; thus, acute kidney injury may be avoided.34,38 Functions of the extremity can be preserved.35 Volkmann’s ischemic contracture can be prevented.38	A closed wound may turn into an open one, increasing the risk of infection and sepsis and resulting in enhanced mortality.9,31-33 Infections may increase the probability of amputations.36 Plasma oozing and bleeding may adversely affect the final outcome.36,38 Sensory and motor deficits in the long term may adversely affect rehabilitation.37

Considering the positive aspects, many authors are in favor of routine fasciotomies. In a literature survey, 80% of all patients with pressure-induced rhabdomyolysis and associated compartment syndrome were fasciotomized.³⁹ However, fasciotomies performed in chaotic circumstances of mass disasters may be complicated by inappropriate wound care and exaggerated risks; therefore, they should be discouraged as a routine intervention.² Most authors suggest that fasciotomies should be undertaken only when clearly indicated, based on clinical conditions²⁷ (absence of distal pulses due to compression, more than expected pain due to an injured limb, or the need for radical debridement of necrotic muscle mass) or objective measurements of intracompartmental pressure. The latter include compartmental pressures in the range of 30-40 mm Hg,^34,40-44 especially if there is no trend to decrease within a 6-hour interval.⁴⁵

If indicated, a fasciotomy should be performed as soon as possible, as the drawbacks are smaller if the intervention is performed within the first 12 hours of muscle swelling.^40,46 If surgical intervention is contraindicated or has a high risk, mannitol infusion may be a medical alternative, as it may result in a decrease in muscle swelling.^2,47,48 Mannitol, however, by itself, has a number of side effects and contraindications and should be administered only under strict conditions. It should also never be considered as an alternative to fasciotomy.

In the Marmara earthquake experience, the mortality rate did not differ significantly between fasciotomized and non-fasciotomized crush victims; on the other hand, sepsis, an important predictor of mortality in that particular database, was more frequent in the fasciotomized patients (P < .0001); and it was concluded that fasciotomy, at least indirectly, increases the risk of mortality.²

Amputations

Amputations are among the most critical and controversial interventions in disaster victims. Seriously traumatized extremities with extensive myonecrosis and with no chance of recovery are potential sources of myoglobin and potassium. Moreover, they always carry the risk of being infected.² Therefore, amputations may prevent crush syndrome and infections, thus saving lives. In principle, a patient should not be sacrificed for saving an extremity.² However, amputations are very demanding interventions that are often followed by an acute deterioration of the general condition of the patient. Also, rehabilitation of patients with amputated extremities is extremely hard in the long run. Therefore, amputations should be performed only with clear indications, e.g., if a limb needs to be abandoned because it cannot be rescued anymore or if it is at the origin of life-threatening sepsis or systemic inflammatory response syndrome. Several symptoms are considered as indicative to decide for amputation, such as loss of bone and extensive soft tissue, loss of distal sensation and motor function related to major peripheral nerve damage, or major vascular injury requiring vascular reconstruction to restore flow. Nevertheless, it is difficult to make a decision based on these criteria, as they remain controversial.⁴⁹ In a meta-analysis evaluating patients with limb-threatening injuries, it was shown that there was no significant difference in functional results between the amputation and limb-salvage surgery methods at 7-year follow-up.⁵⁰ This decision should be made by experts on the spot considering all pros and cons of the operation. If indicated, amputations should be performed as early as possible.⁵¹

In previous disasters, the frequency of amputations among disaster victims has shown significant variation, from 2.9% to 30.9%.^52-54 Several factors, which include but are not limited to the severity of trauma, timing and effectiveness of rescue activities, the status of local medical facilities, and most importantly, the experience of medical teams, contribute to these differences.

In the Marmara earthquake experience, of the 639 crush victims, 95 underwent 121 amputations. The mortality rate of the amputated patients was significantly higher as compared to those without amputations. Moreover, there was a direct correlation between the number of amputated extremities and the risk of death, which can be explained by more serious injuries (and a higher probability of mortality) in the patients who needed higher numbers of amputations.⁹

Controversies exist about the timing of fasciotomies and the related amputations. Delayed application of fasciotomies may lead to necrosis due to inadequate perfusion of the extremity and thus necessitate amputations,³⁵ whereas routinely and early applied fasciotomies may increase the risk of amputations by giving rise to infected fasciotomy wounds.³⁶

Crush syndrome

Literally, “crush” means “compression between opposing elements that result in organ damage or fracture,” whereas “crush syndrome” is a surgical and medical systemic manifestation caused by rhabdomyolysis as a result of crush.²

Pathogenesis

Pathogenetic mechanisms can be studied under the headings of: (i) the etiology and pathogenesis of traumatic rhabdomyolysis and (ii) the pathogenesis of AKI and other features of crush syndrome on the basis of rhabdomyolysis (Figure 2).^45,55-58

Figure 2.

Pathophysiology of crush syndrome on the basis of traumatic rhabdomyolysis. 1. The initial event is a crush injury. 2. Major pathogenetic mechanism is baromyopathy (or pressure-stretch myopathy), which increases sarcolemmal permeability. 3. Shift of plasma water into the muscle tissue triggers the development of compartment syndrome. 4. Several mechanisms, which are triggered by the influx of calcium into the cytosol, contribute to the pathogenesis of traumatic rhabdomyolysis; these mechanisms include the activation of proteolytic enzymes causing myocyte and microvasculature damage, depletion of ATP stores, ischemic damage, and still many others. 5. Intramuscular bleeding may further increase intracompartmental pressure, contributing to the development of compartment syndrome. 6. Disruption of myocytes by the direct effects of trauma has a tertiary role in the whole scenario. 7. Most of the damage occurs after the victim is extricated from under the rubble, which results in an ischemia–reperfusion injury. 8. Traumatic rhabdomyolysis triggers several systemic manifestations. 9. Even if only one of these manifestations (e.g., hypotension, hyperkalemia, AKI, DIC, ARDS infections, and many others) develops as a result of traumatic rhabdomyolysis, the entity is named as “crush syndrome.” (Thethickness of the arrows refers to the impact of the mechanism on the course from crush injury to traumatic rhabdomyolysis. Please see the text for details on rhabdomyolysis-induced crush syndrome development.)^45,55-58 AKI, acute kidney injury; ARDS, adult respiratory distress syndrome; DIC, disseminated intravascular coagulation.

In traumatic rhabdomyolysis, compression of the muscles (baromyopathy) is the key event.⁵⁵ Baromyopathy causes an increased permeability of the sarcolemma and its leakiness to substances abundant in the muscle cells (such as potassium, myoglobin, and phosphate), hence movement to the extracellular environment, while sodium, chloride, water, and calcium diffuse into the cell down their electrochemical gradients, which results in cellular swelling (leading to “compartment syndrome”).⁵⁶ Intramuscular bleeding may contribute to the development of compartment syndrome. Increased intracellular (cytosolic) calcium activates proteolytic enzymes to cause lysis of the muscle fibers. Muscular ischemia on the basis of baromyopathy as well as ischemia–reperfusion injury, which develops during the recovery phase of this ischemia, are additional aggravating factors in the pathogenesis of muscle cell necrosis.⁴⁷

Various factors contribute to the development of crush syndrome and AKI on the basis of rhabdomyolysis.^45,59 However, the most important factor is renal hypoperfusion due to hypovolemia secondary to various factors, especially the compartment syndrome development. Increased levels of vasoconstrictor hormones and cytokines secondary to hypovolemia also impair renal perfusion. Several other factors (e.g., myoglobinuria, increased urate levels in urine, inflammation, and cardiac decompensation) contribute to the pathogenesis of AKI as well.⁶⁰

Clinical findings/course

Clinical findings at admission can be classified as: 1. local signs and symptoms in the traumatized muscles (e.g., pain, pressure, paresthesia, paresis or paralysis, pallor, and pulselesness distant to compartment syndrome) and 2. systemic findings caused by substances released from these muscles (or findings of the crush syndrome). Among the latter, hypovolemic shock, AKI, hyperkalemia, heart failure, respiratory failure, and infections may be cited (Figure 2).^9,31,61,62

Although all body parts can be injured in disaster crush victims, the extremities, especially the lower limbs, are most commonly affected. The number of traumatized extremities is directly related to the need for dialysis.⁹ On the other hand, full-blown crush syndrome can develop even in cases with mild injuries and no apparent initial signs of crush.^38,60

Full-blown AKI in crush syndrome is often characterized by an oliguric phase, which is frequently associated with fluid overload, necessitating ultrafiltration with or without hemodialysis. Follow-up of urinary volume is essential for the assessment of the condition of crush patients, and oliguria is a premonitory sign of AKI, although this condition may also develop with maintenance of a normal urinary volume.

Assessment of laboratory parameters at various stages of the problem (i.e., in the disaster field, at admission to hospitals, and during the clinical course) is useful for directing therapies. Laboratory examinations at the disaster field were not possible until recently. However, in the Haiti earthquake of 2010, the use of a point-of-care device (i-STAT^®) was very useful for the detection of kidney dysfunction and electrolyte disorders, especially hyperkalemia, even in the disaster field.⁶³ On the other hand, after mass disasters, initial laboratory abnormalities can be performed only at admission to hospitals, which mainly include (i) urinalysis and (ii) blood count and biochemical findings.

The most typical finding in urinalysis is a dirty-brownish discoloration of urine as a result of myoglobinuria, although this finding is present in only 50% of the victims. Myoglobinuria may not be present in cases of a low amount of myoglobin released into the plasma, a decreased glomerular filtration rate, and diluted urine.⁶⁴

The most frequent abnormalities in blood count are anemia, leukocytosis, and thrombocytopenia. Biochemistry examinations mostly reveal hypocalcemia, hypoalbuminemia, and increased serum levels of myoglobin, BUN, creatinine, phosphorus, uric acid, and muscle enzymes, especially creatine phosphokinase, which is very useful in the diagnosis of rhabdomyolysis.⁶⁵ Metabolic acidosis, a frequent abnormality in crush patients, may contribute to mortality. However, the most critical and frequent laboratory finding in crush victims is hyperkalemia, which can cause mortality by resulting in cardiac arrhythmias⁶⁶ and should thus be diagnosed and treated as soon as possible. Electrocardiography may be very useful for detecting this fatal abnormality, even at the disaster field.

Prognosis

The mortality rate in disaster crush syndrome victims of the Japan Kobe earthquake was 25%; this figure climbed up to 40% in victims who needed dialysis support.⁵² In the Marmara earthquake crush victims, the overall mortality rate was 15.2%; this rate was 9.3% in the patients who did not require dialysis support and 17.2% in the dialyzed victims,⁶⁷ which is similar to the prognosis of the victims of the Taiwan Chi-Chi earthquake (17% mortality).⁶⁸ Interpreting these statistics as a clue for improved prognosis in patients with crush syndrome may be an oversimplification, since many factors may be effective in improving the outcome of these patients. Long-term prognosis of crush victims has been speculated to be favorable; however, there is no evidence to support this hypothesis.

Prevention and treatment

Major interventions are the maintenance of fluid–electrolyte and acid–base balance, the application of timely dialysis, and the treatment of complications.

Maintaining of fluid–electrolyte and acid–base balance

The first step is assessing the fluid status of the patients. Very simple clinical signs, such as thirst, dry mucosal membranes, a furrowed tongue, decreased skin turgor, decreased blood pressure, and orthostatic hypotension, may all indicate fluid loss or sequestration.⁶⁹ Absolute values of central venous pressure are misleading, and only relative changes may be useful to reflect variations in volume status. In cases of fluid depletion, crystalloids are to be preferred over colloids because colloids are more expensive and have no proven benefit⁷⁰, even obvious disadvantages.⁷¹ The fluid administration protocol before, during, and after extrication has been described in Figure 1.²

A key parameter to guide fluid administration is urine output, which, in a hospital milieu, is best appreciated by inserting a bladder catheter unless contraindicated (suspicion of urethral bleeding or laceration, characterized by blood in the urethral meatus). The catheter should be removed in cases of established oligo-anuric AKI or when kidney function recovers.² Fluid overload in anuric patients is life-threatening, so fluid administration is to be restricted and ultrafiltration with or without dialysis performed.

In crush syndrome-related AKI, acidosis is more severe as compared to AKI secondary to other etiologies. However, parenteral bicarbonate should not be applied unless serum bicarbonate levels drop below 10 mEq/L, because treatment of acidemia by alkaline solutions carries the risk of triggering hypocalcemia and subsequent tetany. However, if more severe acidosis develops, both parenteral bicarbonate and dialysis should be administered to the patient.⁶⁰

Application of dialysis

The patient should be dialyzed in the case of the following indications:² hyperkalemia ≥ 6.5 mmol/L, blood pH ≤ 7.1, BUN ≥ 100 mg/dL or serum creatinine ≥8 mg/dL, uremic symptoms such as volume overload, pericarditis, bleeding, or an otherwise unexplained altered mental status. All these criteria are absolute indications for dialysis initiation. In crush cases, more liberal indications should be considered in anticipation of potential complications.² During the Marmara earthquake, overall, 5137 sessions of hemodialysis were performed to crush victims, which necessitated significant material and personnel help from outside.⁷² This external support was very helpful in preventing extreme tiredness and burnout among local personnel⁷³ and consequently minimizing the risk of malpractice in chaotic circumstances.

Discussing the technical aspects of dialysis applications is out of the scope of this review.

Diagnosis, prevention, and treatment of medical complications

Treatment of hyperkalemia

Serum potassium levels exceeding 7 mmol/L is an emergency, but even serum potassium levels in a lower range necessitate therapy if they rise quickly.² The effects of urgent therapeutic measures that are applied immediately (e.g., calcium gluconate, glucose-insulin infusion, sodium bicarbonate, and beta-2 agonists) are short lived, and disappear within a short time period.² Dialysis is the most effective treatment for this problem.

Treatment of infections

Infections are frequent among crush victims and are a major source of morbidity and mortality.^31,61 Unfortunately, diagnosis might be refrained by chaotic disaster circumstances, whereas clinical signs of infections such as leukocytosis or fever might be elicited by other factors as well, such as hematoma or rhabdomyolysis by itself. Therefore, a high level of suspicion for infections is indicated.²

In crush victims, traumatic and surgical wounds frequently become infected, mainly because of foreign material in the wounds and inadequate wound care due to chaotic conditions. These wound infections may be complicated by sepsis, which is a major cause of mortality.⁹ Hence, meticulous wound care, radical debridement of infected and necrotic tissues, and also early antibiotic administration are of paramount importance. Antibiotics are often selected empirically because of logistical problems in identifying the responsible germs. The most frequent bacteria in crush wounds are Streptococci, Staphylococci, and anaerobic organisms. Hence, β-lactam/β-lactamase inhibitors are the preferred empiric treatment. Central vein catheters should be removed as soon as possible to avoid bacteremia and sepsis.

Differentiation of peripheral neuropathy from spinal cord injury

Peripheral nerve damage due to nerve stretching, immobilization, and compression by increased compartmental pressure is the most frequent neurological complication in patients with crush syndrome.⁷⁴ The usual clinical signs are flaccid paralysis and sensory loss, which occasionally can lead to the misdiagnosis of spinal cord injury. Spinal cord problems are excluded by the presence of urinary sphincter control and pain sensation during bladder catheterization.^56,74 In the presence of peripheral nerve damage, physical therapy and rehabilitation are important to conserve or improve limb function. If a spinal cord injury is diagnosed or suspected, the patient should be immobilized and transferred to a specialized treatment center as soon as possible.

Other medical complications

Several medical conditions and complications may be provoked or exacerbated by crush syndrome or disaster circumstances.⁷⁵ These complications include, but are not limited to, cardiovascular (myocardial infarction, congestive heart failure, hypertension), hematological (anemia, bleeding diathesis), pulmonary (bronchitis, pneumonia, asthma), gastrointestinal (bleeding, peptic ulcer), and psychiatric problems (depression, delirium, and posttraumatic stress disorder).⁶⁰ Early diagnosis and appropriate treatment of these complications are mandatory to improve the ultimate outcome of the victims.

Avoidance of nephrotoxicity

In crush patients, any of the factors with a negative impact on kidney function and thus on the recovery of AKI, such as the usage of nephrotoxic agents, the development of urinary tract obstruction, urinary or systemic infections, hypotension, hypertension, heart failure, gastrointestinal bleeding, and anemia, should definitely be avoided or treated.² Among the nephrotoxic agents, a prominent contraindicated group is non-steroidal anti-inflammatory drugs⁷⁶ Also, aminoglycosides and intravenous radiocontrast agents are to be avoided.

Recovery phase

The recovery phase of crush-related AKI is usually characterized by a polyuric phase.⁹ During this period, the daily loss of fluid and electrolytes should be adequately compensated. Serum and urinary electrolytes should be checked daily. Hypovolemia should definitely be avoided. Once kidney function tends to improve, fluid compensation can gradually be tapered, with a continued checkup of volume and electrolyte status.

From a logistical point of view, in order to provide the most effective healthcare throughout the predisaster period and also to minimize postdisaster chaos, it is very important to make preparations for anticipated disasters.⁷⁷

Conclusion

Destructive disasters result in sudden deaths in majority of the casualties. The traumatized victims who survive the disaster suffer from direct and indirect complications of trauma. Treatment principles during mass disasters may show significant variation as compared to routine practice due to medical factors and logistical circumstances. Crush syndrome, an indirect consequence of traumatic rhabdomyolysis, is a major cause of mortality in disaster victims. Including disaster medicine courses in medical curricula and organizing repeated training courses on disaster medicine may be helpful to provide the most effective healthcare and save as many lives as possible after mass disasters.

Funding Statement

The authors declared that this study has received no financial support.