Blast impact injury is due to the explosion of the formation of shock waves acting on the human body due to the release of energy and a variety of injuries, is a primary explosion injury.
Blast impact injury on the human body has the following injury characteristics.
1, external light weight: due to the shock wave overpressure and negative pressure of their own characteristics, injuries are often more serious than those perceived by the naked eye from the body, the implosion effect, fragmentation effect, hemodynamic changes, inertial effects, pressure differential effects and biomechanics of the abdominal cavity, parenchymal organs and the same organ density inconsistent parts and blood vessels can cause great damage;
2, multiple injuries, injury inert complex: impact injury patients are not only subject to the role of super-pressure injury, but also subject to the corresponding dynamic pressure, so there may be both direct and indirect injuries, both external and internal injuries, such as not a comprehensive examination and careful observation, easy to miss, misdiagnosis, leading to serious consequences;
3, the rapid development of the injury: more than severe impact injury patients, a relatively stable compensatory period can occur in the short term after the injury, when vital signs can be maintained normal, but soon will be due to compensatory disorders and aggravation of the injury and the systemic situation deteriorates sharply, if not timely treatment, the patient can quickly die. Air shock wave caused by abdominal injuries to the majority of substantive organ damage, while underwater explosions shock wave caused by more cavity organ damage. The incidence of abdominal blast impact injuries in wartime can reach 11% -17%.
Diagnosis
The history of abdominal blast impact injuries is an important element. Interviewing the patient provides detailed information about the environment at the time of injury, the type of explosive, and the specific state of the explosion, all of which contribute to a full and comprehensive understanding of the injury. Physical examination, especially comprehensive and dynamic observation of signs, can help determine the development of the injury and adjust the treatment plan in a timely manner. Auxiliary examination items need to be based on the patient’s injury and hemodynamic stability, try to do not miss.
1, clinical manifestations.
Abdominal blast impact injury is mainly caused by intra-abdominal hemorrhage and peritonitis. Hemorrhage to parenchymal organ rupture, such as liver, spleen rupture and vascular injury is prominent; peritonitis is caused by the rupture of cavity organs, gastrointestinal contents spilled into the peritoneal cavity.
There are different manifestations depending on the site of injury and the injury as follows.
(1) abdominal pain: the most common symptom, starting mostly at the site of injury and then diffusing to the whole abdomen. Perforation of the stomach, upper intestinal canal and gallbladder, etc. is likely to cause diffuse severe pain; colon perforation is less painful and more limited, but is likely to cause infectious shock.
(2) nausea and vomiting: nearly half of the patients with abdominal blast impact injuries have brief or persistent post-injury nausea and vomiting symptoms.
(3) shock: shock can result from massive intra-abdominal hemorrhage or severe diffuse peritonitis.
(4) Peritoneal irritation signs: Patients with visceral rupture may develop peritoneal irritation signs such as pressure pain, rebound pain, and abdominal muscle tension.
(5) Other: hematuria may occur with kidney and bladder injury. Dark purple or black blood stools may occur in the case of intestinal mucosal injury or intestinal perforation; blood flow from the anus indicates colon or rectal injury. Pneumoperitoneum, pneumoperitoneum and loss of hepatic turbinates may occur in the case of gastric and intestinal perforation, along with loss of bowel sounds, fever and frequent pulse. Pelvic organ injury can stimulate the rectum and have frequent bowel movements. Patients with abdominal blast impact injuries due to underwater explosions have a number of complications of temporary lower extremity mild paralysis, which may be due to small vessel injury within the spinal cord. It is important to note that if pain medications have been used during evacuation, the signs and symptoms may not manifest themselves significantly.
It should also be noted that multiple traumas, from time to time, the symptoms of other parts of the injury obviously mask the symptoms of abdominal injuries, such as patients who are in a coma due to cranio-cerebral injury, cannot provide conscious symptoms of the abdomen; combined thoracic and abdominal injuries may focus on the chest and neglect the examination of the abdomen due to the symptoms of chest wounds and respiratory distress; fractures of long bone injuries of the limbs also often mask the abdominal injuries.
2, auxiliary examination.
(1) X-ray film, CT examination: abdominal X-ray film examination can determine the presence of gastrointestinal perforation, but the application is relatively limited; suspected of kidney and ureteral injury, intravenous pyelogram can be used. At present, it is believed that the accuracy of multi-row spiral CT examination is higher than that of abdominal radiography in the diagnosis of most abdominal injuries, and its application in the diagnosis of abdominal blast impact injuries is gaining attention.
(2) Diagnostic laparotomy: this test can be done when closed abdominal organ injury is suspected, and is positive if bloody fluid is withdrawn. This method is simple and rapid, and its positive rate can reach 83.0%-97.7% for closed trauma.
(3) Diagnostic lavage: When there is less blood or exudate in the abdominal cavity, laparotomy is often negative, and lavage can be used at this time. It is positive if the lavage fluid is light red or microscopic red blood cell count >0.1×1012/L, or white blood cell count >0.5×109/L, or if there are bacteria, bile, vegetable fibers or fecal residue in the lavage fluid. The accuracy of this method can reach 97%.
(4) Ultrasonography: this method is simple, rapid, non-invasive, can be performed at the bedside, and can also be repeatedly observed dynamically, and has a greater diagnostic value for liver, spleen, kidney, pancreas and other substantive organ injuries and the presence of retroperitoneal hematoma and intra-abdominal fluid.
(5) Laparoscopy: laparoscopy is both an examination technique and can also do some therapeutic procedures, but its application is relatively limited. Due to the lack of palpation, it is deficient in fully exploring the abdominal organs.
(6) Catheterization: If the exported urine is clear and bloodless, it indicates no bladder injury; if there is a large amount of hematuria, it suggests damage to the bladder, ureter or kidney; if there is no urine exported or only a small amount of hematuria, 50-100 ml of sterile isotonic fluid can be injected from the catheter and then aspirated after a few minutes; if the aspirated amount is significantly less than the injected amount or with blood, it proves that there is bladder rupture.
(7) Laboratory tests: routine blood, liver and kidney function, arterial blood gas analysis, urine, and gastric juice are important for judging the local and systemic functions of the patient.
Treatment
1.Treatment principles
The most life-threatening injuries should be treated first, such as keeping the respiratory tract open and controlling obvious bleeding. Not all patients with abdominal blast impact injuries require surgical treatment; for patients treated non-operatively, observation should be continued for 1 to 2 weeks, with attention to the risk of delayed perforation of the gastrointestinal tract.
For patients who have not yet been diagnosed or are under observation and cannot be determined for surgery, they need to be fasted from food and water, while no analgesic treatment should be given. For patients who have been diagnosed and need to wait for surgery, analgesia can be given to relieve the patient’s pain. The timing of surgery should be based on the patient’s injury (especially in combination with other organ injuries) to decide whether to operate in stages or at the same time. A transrectal or median incision is preferable for abdominal exploration, and adequate exploration is required to avoid missed diagnoses. Especially for some gastrointestinal myocardial hematoma and perforation of the mesenteric margin, repeated and careful examination is required. For ballistic injuries, one should not be satisfied with finding a particular wound. It is advisable to operate quickly, safely, accurately, without missing visceral injuries, and adequate drainage is required after surgery.
2.Treatment process
(1) quickly do a general examination to determine whether there are intra-abdominal organ injuries and other parts of combined injuries, such as respiratory and circulatory dysfunction, should be limited initial resuscitation, if necessary, endotracheal intubation, emergency tracheotomy or closed drainage of the chest, in order to release the airway obstruction, to maintain a smooth airway, positive pressure ventilation need to prevent air embolism, and then do abdominal injury treatment, if necessary, the need for simultaneous surgery.
(2) fasting, water, placement of gastric tube, continuous gastrointestinal decompression, and observe whether there is bleeding.
(3) Place a urinary catheter and record the urine volume.
(4) Replenish blood volume: for patients with suspected visceral injury, blood should be drawn quickly for blood type cross-testing. For patients with more bleeding and severe shock, two or even three to four infusion channels should be established for simultaneous infusion. In critically injured patients, anti-shock should be performed while performing dissection.
(5) Early application of broad-spectrum antibiotics and metronidazole anti-infection, for those who have not used tetanus toxoid should be injected tetanus antivenom.
(6) The management of abdominal wall injuries should be prepared for dissection.
(7) dissection: for serious abdominal injuries, focus on the early implementation of rescue surgery, especially the rescue of hemorrhagic shock. For patients with particularly serious conditions, we should race against time to win time to save lives. Early dissection is the key point and difficult point of critical trauma treatment, and we should not delay the time of resuscitation by one-sidedly emphasizing the correction of hypotension, which may lead to the death of patients. The operation should be simple, short and effective, with the aim of repair, hemostasis, drainage, closure of abdominal cavity and damage control.
Treatment procedure
For patients with unstable vital signs of abdominal blast impact injury, the relevant auxiliary examinations should be completed while emergency resuscitation is performed to clarify the diagnosis, determine the injury condition and further triage treatment, and to conduct a comprehensive record and assessment of the patient’s general condition, symptoms and signs of impact injury.
After the diagnosis is clear, the exact treatment is carried out according to the principles of abdominal blast impact injury treatment.