Monthly Archives: May 2011

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When to Give Spleen Vaccines After Splenectomy for Trauma

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I’ve written previously on the (f)utility of giving vaccines after splenectomy for trauma (click here to read). However, it is more or less a medicolegal standard, so pretty much everyone gives them. The big question is, when? 

Some centers give them immediately postop, some before hospital discharge, and some during their postop visit. Who is right? The argument is that major surgery produces some degree of immunocompromise. So if the vaccines are given too early, perhaps the anitbodies will not be processed as effectively, and the response to an actual bacterial challenge might not be as good.

One prospective study randomized patients to receive their pneumococcal vaccine either 1, 7, or 14 days after surgery. IgG levels were measured before vaccination and again after 4 weeks. This study found that antibody concentrations were the same in all groups. However, functional activity of the antibodies was low in the 1 and 7 day groups, and nearly normal in the 14 day group.

Following this, a rat study looked at vaccination timing followed by exposure to pneumococcus. These animals were splenectomized, then given a real or sham vaccination at 1, 7, or 42 days. They then had pneumococcus injected into their peritoneal cavity. About 70% of all rats with sham vaccination died. Only 1.5% of the vaccinated rats died, and there were no differences based on vaccination timing.

Bottom line: Neither antibody titer studies nor rat studies easily translate into recommendations for treating overwhelming post-splenectomy sepsis (OPSS) in humans. And such a study can never be done because of the rarity of this condition (less than 70 cases since the beginning of time). It really boils down to your specific population, balancing your assurance that your patient will get it against the possibility that their immune system may not react to it as much as it could. 

At our center, we give the vaccines as soon as possible postoperatively. This ensures that it is given, and erases any doubt of what might happen if the patient does not show up for their postop check.

References:

  • Immune responses of splenectomized trauma patietns to the 23-valent pneumococcal polysaccharide vaccine at 1 versus 7 versus 14 days after splenectomy. J Trauma 44(5):760-766, 1998.
  • Timing of vaccination does not affect antibody response or survival after pneumococcal challenge in splenectomized rats. J Trauma 45(4):682-697, 1998.

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    General

    Pneumothorax in Children

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    Last week I wrote about pneumomediastinum in children (click here to read). This week I’ll talk about a somewhat more common problem: pneumothorax. This condition is far more mysterious than in adults.

    Sports related pneumothorax rarely occurs without rib fractures, which are themselves uncommon in children. The usual mechanism is barotrauma, most likely from an impact while the glottis is closed. The typical presentation is that of pleuritic chest pain, which may be followed by dyspnea. Focal chest wall tenderness is typically absent. Teenagers tend to engage in more strenuous activity and are more likely to actually sustain a rib fracture, so they may have focal tenderness over the fracture site.

    Spontaneous pneumothorax in children is also uncommon. However, it is a very different entity. It may be related to blebs in the lungs, and may be more common in children who were born prematurely. The recurrence rate after successful treatment is approximately 50% (in small series). Recurrence is not predictable by looking for blebs on chest CT. The recurrence rate is significantly lower after VATS.

    Bottom line: A child who complains of pleuritic chest pain, and especially dyspnea, should undergo a simple PA chest xray. If a pneumothorax is present, consider the following:

    • Insert a small chest tube or catheter if needed, the smaller the better. (I’m stilling looking for the answer to the question of how big a pneumothorax is big enough)
    • Don’t use high inspired oxygen; it doesn’t work. (Read my older blogs from 2010 – this one and this one, too)
    • Don’t get a chest CT for either the initial pneumothorax or any recurrences (too much radiation, too little utility)
    • If this is a spontaneous pneumothorax, caution the parents on the possibility of recurrence
    • If a spontaneous pneumothorax does recur, consult a pediatric surgeon to consider VATS pleurodesis
    • When can the child return to sports? There is absolutely no good literature. I recommend the usual time it takes most soft tissues to return to full tensile strength after injury (6 weeks).

    References:

    • Management of primary spontaneous pneumothorax in children. Clin Pediatr, online ahead of print, April 11, 2011.
    • Sports-related pneumothorax in children. Pediatric Emergency Care 21(4): 259-260, 2005.

    Related posts:

    Thanks to Chris Chow MD for finding some of the literature for this post.

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    New Technology II: Helping Paraplegics and Quadriplegics to Walk

    The second company that makes a device to assist walking in spinal cord injured patients is Berkeley Bionics. Their exoskeleton is lighter (45 pounds) and more form-fitting, making it easier to maneuver indoors. It can operate for up to 6 hours between charges. The unit does require operator assistance in the form of a pair of canes for balance.

    Prices were not available for the products from both Berkeley and Rex. However, the technology looks promising for several reasons. It allows the subject to stand upright, putting weight on their feet. This helps increase muscle tone and maintain joint flexibility. It also decreases pressure problems caused by remaining seated.

    These devices are in an early stage right now. As the technology advances, expect to see smaller bionics with better (smoother) computer control, and more access for people with higher spinal cord injuries.

    Disclaimer: I have no financial interest in Berkeley Bionics.

    (Source: https://www.youtube.com/)
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    New Technology I: Helping Paraplegics and Quadriplegics to Walk

    Several companies are working on technology to enable people with spinal cord injuries to walk again. Dave MacCalman, a New Zealand Paralympian with a cervical cord injury, recently purchased a robotic exoskeleton from Rex Bionics. This device allowed him to walk for the first time in 30 years. 

    This exoskeleton is somewhat bulky (84 pounds), and allows only slow movement. The unit does not use crutches, but does require a modest amount of arm strength to use. It allows walking up slopes and building standard stairs with a handrail. To go down stairs, the user steps down facing backwards. The power supply lasts 3-4 hours.

    This technology has only been in development for nonmilitary use for a few years. I expect that great strides (!) will be made as more companies join the fray. Tomorrow I’ll feature an exoskeleton from a US company, and point out the pros and cons of the two devices. 

    Disclaimer: I have no financial interest in Rex Bionics.

    (Source: https://www.youtube.com/)
    General

    Fatigue Week V: Final Thoughts

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    Fatigue is a major problem for many healthcare providers, from prehospital those working in post-discharge institutions. Some interesting and underappreciated statistics about work-related injuries and shift work:

    • Work related injuries increase on off-shifts. Compared to day shift, 15% more injuries occur on evenings and 28% more on nights.
    • When working long shifts, there is a 13% increase in injuries after 10 hours, and a 30% increase after 12 hours.
    • When working consecutive nursing shifts, there is an 8% increase in injury risk the 2nd night, a 38% increase the 3rd night, and a 70% increase the 4th night.

    We know sleep deprivation and fatigue are bad. The laundry list of adverse effects is lengthy and includes confusion, memory problems, depression, weight gain, headache, diabetes, cardiovascular disease, and as we’ve discussed all week, serious performance problems.

    What can be done about it? The key is to raise awareness, along with acceptance of the remedies. Many hospital workplaces are doing something about it. Here are some successful interventions that reduce workplace fatigue:

    • Authorize a real break system. A break is a 30 minute period which is ideally away from the immediate work setting, where there are no disturbances (phone, pager)
    • Ensure effective “handoffs” between co-workers when taking breaks
    • Encourage workers to identify fatigue in their co-workers and find ways to decrease it
    • Modify schedules to adhere to the Institute of Medicine’s standards
         * No more than 20 hours of overtime a week
         * Limit the number of 12 hours shifts
         * No double shifts 

    Some workplaces are unfortunately not as progressive, and the work culture takes pride in showing how individuals can “power through” even when tired. Just remember, this is bad for you and bad for your patients. As you grow older, it becomes even more difficult and dangerous. It’s only a matter of time before someone, somewhere goes too far, and they or their patient will end up “dead tired.”