Intraosseous (IO) Access Techniques
Yesterday I wrote about using an intraosseous line (IO) to administer contrast for CT scanning. The authors of the paper I cited prefer using humeral head access for their IO device. I wanted to share a nice video illustrating the technique, especially for those of you who use the tibia.
The technique is simple, and better tolerated in awake, unanesthetized patients than leg access. However, I believe it’s easier to find the insertion landmarks for the tibia in obese patients.
Related post: CT contrast administration through an IO line
The standard of care in vascular access in trauma patients is the intravenous route. Unfortunately, not all patients have veins that can be quickly accessed by prehospital providers. Introduction of the intraosseous device (IO) has made vascular access in the field much more achievable. And it appears that most fluids and medications can be administered via this route. But what about iodinated contrast agents via IO for CT scanning?
Physicians at Henry Ford Hospital in Detroit have just published a case report on the use of this route for contrast administration. They treated a pedestrian struck by a car with a lack of IV access sites by IO insertion in the proximal humerus, which took about 30 seconds. They then intubated using rapid sequence induction, with drugs injected through the IO device. They performed full CT scanning using contrast injected through the site using a power injector. Images were excellent, and ultimately the patient received an internal jugular catheter using ultrasound. The IO line was then discontinued.
This paper suggests that the IO line can be used as access for injection of CT contrast if no IV sites are available. Although it is a single human case, a fair amount of studies have been done on animals (goats?). The animal studies show that power injection works adequately with excellent flow rates.
The authors prefer using an IO placement site in the proximal humerus. This does seem to cause a bit more pain, and takes a little practice. A small xylocaine flush can be administered to reduce injection discomfort in awake patients. Additionally, the arm cannot be raised over the head for the torso portion of the scan.
Bottom line: CT contrast can be injected into an intraosseous line (IO) with excellent imaging results. Insert the IO in a site that you are comfortable with. I do not recommend power injection at this time. Although the marrow cavity can support it, the connecting tubing may not. Have your radiologist hand-inject and time the scan accordingly.
Note: long term effects of iodinated contrast in the bone marrow are not known. For this reason, and because of smaller marrow cavities, this technique is not suitable for pediatric patients.
Related post: Air embolism from an intraosseous line
Reference: Intraosseous injection of iodinated computed tomography contrast agent in an adult blunt trauma patient. Annals Emerg Med 57(4):382-386, 2011.
Yesterday, I wrote about using ultrasound in place of CT for initial diagnosis of blunt abdominal injury in children. Although it looks good for identification of solid organ injury and free fluid, it may miss injury to the intestine. Is that bad?
Lets look at a recent study that examined the consequences of delayed laparotomy for blunt intestinal injury. The American Pediatric Surgical Association conducted an 18-center study of the management of intestinal injuries in children less than 16 years of age. They were stratified by time to treatment. There were 214 patients with complete data records for review.
The majority of the patients were involved in a motor vehicle crash or a bicycle accident. Demographics were similar in all time to treatment groups. Half were resuscitated at a referring hospital and then transferred to a pediatric trauma center, on average after 6 hours.
- The only deaths occurred in the 0-6hr and 6-12hr groups. The average Injury Severity Score of the children who died was significantly higher than survivors.
- Children operated on in the 0-6hr group had significantly higher ISS as well.
- There was no difference in early or late complications across all groups.
- Time to beginning oral intake and time in hospital were the same in all groups.
The authors concluded that observation and serial exam rather than urgent exploration or repeated CT scans is appropriate.
Bottom line: If you combine this study with the ultrasound study I reviewed yesterday, it seems appropriate to modify the usual (read: adult) way of evaluating blunt trauma to the abdomen. In place of automatically getting a CT scan of the abdomen in children, obtain a complete abdominal ultrasound to detect solid organ injury or free fluid. This will determine the degree of monitoring needed (e.g. ICU for higher grade liver or spleen injuries). Follow this with serial abdominal exam. If the child becomes symptomatic, it’s probably time to proceed to the OR. Note: I generally do not make children npo during the observation phase. They need to eat, and if they don’t want to, that tells you something.
Related post: Sonography in pediatric abdominal trauma
Reference: Delay in diagnosis and treatment of blunt intestinal injury does not adversely affect prognosis in the pediatric patient. J Pediatric Surg 45(1):161-166, 2010.
Pediatric blunt abdominal trauma is not common, but if present it has the potential to cause significant morbidity or mortality. Evaluation of the abdomen at the trauma center is crucial, and most trauma professionals are aware of the trade-offs in the use of CT scan in children (radiation exposure, need for sedation).
Ultrasound is widely available and allows for imaging of most areas of concern in the abdomen. Could sonography be used in place of CT in specific cases? Pediatric surgeons in Germany (who have been using ultrasound far longer than the US has) published a paper last year looking at their experience with children who were diagnosed with an intra-abdominal organ injury after blunt trauma. Their 7 year experience only produced 35 such children, and they were evaluated with examination and one or more serial FAST ultrasound exams. Equivocal results were scanned with CT.
They found that ultrasound was effective in diagnosing abdominal injury 97% of the time. Although 11 of the 35 children had subsequent CT scanning, it only changed management in one case.
Bottom line: Obviously, this is a very small retrospective series, but it is provocative. The German pediatric surgeons go above and beyond the typical FAST exam in the US, using it for diagnostic purposes as well. Could a complete diagnostic ultrasound take the place of CT in select children in the US? Probably so, as they are very sensitive in detecting free fluid and solid organ injury. But what about blunt intestinal injury? I’ll review that tomorrow and sum up my thoughts on a possible algorithm.
Reference: Is sonography reliable for the diagnosis of pediatric blunt abdominal trauma? J Pediatric Surg 45(5):912-915, 2010.
Seatbelt use has increased from 58% in 1994 to a high of 85% last year. We know that seatbelt use saves lives, but trauma professionals are also aware that they can create their own injuries as well. This is a positive trade-off, because belt use prevents injuries that are difficult to treat (e.g. severe brain injury) and produces a higher number of intra-abdominal injuries that are easy to treat.
The spectrum of injuries attributed to seat belt use was finally appreciated in a journal article published 20 years ago this month. The authors wanted to catalog the various injuries seen in belted and unbelted motor vehicle occupants. They reviewed data from the North Carolina Trauma Registry, one of the most sophisticated state registries at the time. Although there were over 21,000 records in the database, only 3,901 involved motor vehicle crashes and had complete data on seatbelt use.
This study found the following:
- Mortality was higher in those not wearing their seat belts (7% vs 3.2%)
- Unbelted had a much higher incidence of severe head injury (50% vs 33%)
- Overall incidence of any abdominal injury was the same for both (14%)
- GI tract injuries were more common in the belted group (3.4% vs 1.8%)
- Solid organ injury was the same
Bottom line: This study sparked the recognition that seatbelts reduce severe head injury but increase the incidence of some hollow viscus injuries. About 514 severe head injuries were prevented in exchange for 21 additional abdominal injuries that were generally easily repaired. Good tradeoff!
Reference: The spectrum of abdominal injuries associates with the use of seat belts. J Trauma 31(6):821-826, 1991.