Tension pneumoperitoneum after blast injury: dramatic improvement in ventilatory and hemodynamic parameters after surgical decompression

Tension pneumoperitoneum caused by blunt thoracic trauma

Tension pneumoperitoneum is a rare entity that occurs when free air under pressure accumulates in the abdominal cavity compromising visceral function and blood flow. The case of a 23-year-old man whose chest was run over by the wheels of a truck is presented. He arrived with a severely distended abdomen, significant thoracic trauma, hypoxemia, and elevated airway pressures following intubation. Imaging studies revealed massive intraperitoneal free air. He was treated with a decompressive laparotomy but was not found to have a hollow viscus nor diaphragmatic injury. We hypothesize a possible, as yet unpublished, mechanism: secondary to the patient’s rib fractures and significant torso soft tissue shearing, a defect in the parietal pleura allowed air to track from the thorax inferiorly along subcutaneous and fascial planes, eventually entering into the peritoneal cavity through a violated parietal peritoneum. We present a review of the literature on tension pneumoperitoneum.

Pneumoperitoneum without visceral trauma: an under-recognised phenomenon after blast injury?

OBJECTIVES

The management of patients who have sustained blast injuries poses an important challenge for military healthcare professionals. Current military operations are generating large numbers of casualties and modern military healthcare facilities are increasingly using CT scanning to facilitate their management. This small case series serves to draw attention to a rare (or possibly under-reported) phenomenon after blast injury.

METHODS AND RESULTS

We report two patients exposed to blast who had pneumoperitoneum identified by CT scan but who did not have abdominal visceral injury or ballistic peritoneal violation.

DISCUSSION

The use of cross-sectional imaging is leading to the recognition of otherwise occult injury. Military practitioners should be aware of this injury pattern when using CT to help select patients for conservative management after abdominal blast injury.

Abdominal trauma in primary blast injury

BACKGROUND

Blast injury is uncommon, and remains poorly understood by most clinicians outside regions of active warfare. Primary blast injury (PBI) results from the interaction of the blast wave with the body, and typically affects gas-containing organs such as the ear, lungs and gastrointestinal tract. This review investigates the mechanisms and injuries sustained to the abdomen following blast exposure.

METHODS

MEDLINE was searched using the keywords 'primary blast injury', 'abdominal blast' and 'abdominal blast injury' to identify English language reports of abdominal PBI. Clinical reports providing sufficient data were used to calculate the incidence of abdominal PBI in hospitalized survivors of air blast, and in open- and enclosed-space detonations.

RESULTS

Sixty-one articles were identified that primarily reported clinical or experimental abdominal PBI. Nine clinical reports provided sufficient data to calculate an incidence of abdominal PBI; 31 (3·0 per cent) of 1040 hospitalized survivors of air blast suffered abdominal PBI, the incidence ranging from 1·3 to 33 per cent. The incidence for open- and enclosed-space detonations was 5·6 and 6·7 per cent respectively. The terminal ileum and caecum were the most commonly affected organs. Surgical management of abdominal PBI is similar to that of abdominal trauma of other causes.

CONCLUSION

Abdominal PBI is uncommon but has the potential for significant mortality and morbidity, which may present many days after blast exposure. It is commoner after blast in enclosed spaces and under water.

Primary blast injury: update on diagnosis and treatment

BACKGROUND

: Injuries from combat and terrorist explosions are increasing worldwide. As such, physicians can expect to treat more patients with complex and unique patterns of injury produced not only by fragments and blunt trauma, but also by high-pressure air expanding from the detonation center.

DISCUSSION

: Tissue damage from the blast wave or primary blast injury can be an important cause of occult trauma to the ocular, aural, pulmonary, cardiovascular, musculoskeletal, and neurologic systems. Awareness of the extensive corporal effects of the blast wave is an essential prerequisite to diagnosis.

SUMMARY

: This article focuses on the incidence, risk factors, diagnosis, management, and screening for primary blast injury.

Management of pneumothorax and barotrauma: current concepts

Pneumothorax can be spontaneous, traumatic or iatrogenic. Pneumothorax ex vacuo, sports-related pneumothorax and barotrauma unrelated to mechanical ventilation are interesting and newer entities. Management consists of getting rid of the air and prevention of recurrence of pneumothorax.

Explosions and blast injuries

Powerful explosions have the potential to inflict many different types of injuries on victims, some of which may be initially occult. Flying debris and high winds commonly cause conventional blunt and penetrating trauma. Injuries caused by blast pressures alone result from complex interactions on living tissues. Interfaces between tissues of different densities or those between tissues and trapped air result in unique patterns of organ damage. These challenge out-of-hospital personnel, emergency physicians, and trauma surgeons to specifically seek evidence of these internal injuries in individuals with multiple trauma, adjust management considerations to avoid exacerbation of life-threatening problems caused by the blast wave itself, and ensure appropriate disposition of these patients in possible mass-casualty situations. Knowledge of the potential mechanisms of injury, early signs and symptoms, and natural courses of these problems will greatly aid the management of blast-injured patients.

Pneumoperitoneum: a review of nonsurgical causes

OBJECTIVE

To review causes of nonsurgical pneumoperitoneum (NSP), identify nonsurgical etiologies, and guide conservative management where appropriate.

DATA SOURCE

We conducted a computerized MEDLINE database search from 1970 to 1999 by using key words pneumoperitoneum and benign, nonsurgical, spontaneous, iatrogenic, barotrauma, pneumatosis, diaphragmatic defects, free air, mechanical ventilation, gynecologic, and pelvic. We identified 482 articles by using these keywords and reviewed all articles. Additional articles were identified and selectively reviewed by using key words laparotomy, laparoscopy, and complications.

STUDY SELECTION

We reviewed all case reports and reviews of NSP, defined as pneumoperitoneum that was successfully managed by observation and supportive care alone or that required a nondiagnostic laparotomy.

DATA SYNTHESIS

Each unique cause of nonsurgical pneumoperitoneum was recorded. When available, data on nondiagnostic exploratory laparotomies were noted. Case reports were organized by route of introduction of air into the abdominal cavity: abdominal, thoracic, gynecologic, and idiopathic.

CONCLUSIONS

Most cases of NSP occurred as a procedural complication or as a complication of medical intervention. The most common abdominal etiology of NSP was retained postoperative air (prevalence 25% to 60%). NSP occurred frequently after peritoneal dialysis catheter placement (prevalence 10% to 34%) and after gastrointestinal endoscopic procedures (prevalence 0.3% to 25%, varying by procedure). The most common thoracic causes included mechanical ventilation, cardiopulmonary resuscitation, and pneumothorax. One hundred ninety-six case reports of NSP were recorded, of which 45 involved surgical exploration without evidence of perforated viscus. The clinician should maintain a high index of suspicion for nonsurgical causes of pneumoperitoneum and should recognize that conservative management may be indicated in many cases.