Patchy Consolidation, often Bilateral, was the Most Common Chest X-ray Finding Associated with A(H1N1) Infection?

In a recent study done on 66 out of 222 patients with A(H1N1) from May to July 2009 at a hospital in Michigan, who also had chest radiography findings done as part of the clinical work-up, it was found that the

• initial radiograph was abnormal in 28 of the 66 patients (42%)
• with patchy consolidation in 14 out of these 28 (50%)
• ground-glass opacities in 7 out of 28 (25%), and
• ground-glass opacities mixed with consolidation in 7 (25%)
• the abnormalities were bilateral in 20 of the 28 patients (71%)
• located in the lower lung zones in 20 (71%), and
• diffuse in 7 (25%).

In short, these results suggest that H1N1-associated chest x-ray abnormalities tend to be dependent (i.e., in the lower lungs) and patchy consolidation, often bilateral, was the most common finding chest X-ray finding. Nevertheless, much of its mechanism remain unknown pending further larger studies.

Click here to download the full text of the article in full (pdf format)

Responding To Cardiac Arrest - Every Minute Counts!

A Singapore medical team is endeavoring on an ambitious target of emergency response time of 2 minutes (see the news from Channel News Asia below)

This would be especially important in setting of responding to a sudden cardiac arrest case where every minute counts! The reasons being:

• Resuscitation is most successful if defibrillation is performed in about 5 minutes after collapse
• Effective bystander CPR, provided immediately after cardiac arrest, can double a victim’s chance of survival (Click here to download the entire AHA Guidelines 2005 in pdf free)
• Even with the latest development of various gadgets and medications, the interventions that unquestionably contribute to improved survival after cardiac arrest are early defibrillation for VF/pulseless VT and prompt effective bystander BLS
  

Unfortunately, one of the shortcomings of responding to cardiac arrest in Malaysia is the ambulance response time which may take between 15 to 20 minutes or longer (click here to read my article on Shortcomings of Cardiopulmonary Resuscitation in Malaysia or download the article in pdf). Furthermore, our public may be reluctant to perform mouth-to-mouth breathing on a total stranger that we do not know, especially when responding to a victim of a different gender. This could probably be due to the socio-cultural barrier in our community (click here to read or here to download in pdf the article on the survey that I have done with my colleague, Dr. Yazid on the attitudes of our own students in responding to cardiac arrest).

Fortunately, in responding to non-traumatic sudden cardiac arrest in an adult (which most commonly due to a coronary event), it has been found that cardiac compression is more important than mouth-to-mouth breathing. In fact, the American Heart Association (AHA) is advocating performing Hands Only CPR or compression-only CPR in cases when the potential rescuer is not familiar with the steps of CPR or unwilling to perform to mouth-to-mouth breathing.

Hands Only CPR is simplified to 2-step only:
1. Call for emergency medical response (in Malaysia, it is 999)
2. Put your hands in the center of the victim's chest and start pushing fast and hard

Click here to read more on Hands Only CPR or download an article in pdf.
(*Of course, in cases where the primary insult is asphyxia or respiratory etiology, for example, drowning in children, respiratory failure in children, toxicology cases, oxygenation is still very important and in such cases, rescue breathing is important).

Watch the video on Hands Only CPR below:

*********************

SINGAPORE: A medical centre and two medical posts have been set up within Suntec Singapore to take care of APEC delegates. And if needed, a team on standby can render help within two minutes.

So far, there have been no emergency cases.

Three doctors and six nurses are on duty everyday.

And since the start of the summit last Saturday, the medical team has been seeing an average of 10 patients daily, mostly for minor illnesses such as flu, headaches and abdominal pains.

The team is also equipped to respond to major cases like heart attacks and any incident which may involve many casualties.

Suresh Pillai, head, APEC Medical Sub-Committee, said: "There will be an extra medical team that will be activated from all the hospitals. All hospitals will have a field medical team on standby to move in the event of a mass casualty incident.

“So they have been prepped to be on standby and move out within five minutes in a mass casualty incident and they will response to whichever site the incident may be in."

On the potential threat of Influenza A H1N1, the team's response will be similar to any flu-like illness, but precautions are in place.

Mr Suresh added: "We have to make sure that we have the anti-viral drugs available and we also needed to ensure that we could do H1N1 testing at the medical centre itself. At this point of time, there is probably no need to do any of these things, since the situation is well controlled and stabilised."

Those who require follow up treatment in hospital, will be sent to the Singapore General Hospital or National University Hospital.

VVIPs who need to be sent to the hospital will be escorted by police.

Media personnel too are well-taken of with a 24-hour medical centre within the media area.

The media centre is also opened round the clock, housing some 30 broadcast booths and 300 work stations. - CNA

The Use of Exhaled Nitric Oxide Measurements In Asthma

Not many of us know that there is a new marker for bronchial asthma - to aid the diagnosis, therapeutic monitoring, control monitoring, etc. This marker has been studied in many trials, but how extensive will this marker be used in clinical practice? Will it be readily available in emergency departments for day to day clinical use in the near future?

The past few decades have seen a paradigm shift in our understanding of the pathogenesis of bronchial asthma.

Rather than seeing bronchial asthma as a bronchoreactive airway disease, it is now seen as a TH-2 mediated inflammatory disease that involves both the large and small airways (Busse & Lemanske, 2001).

In fact, studies done during these last three decades have shown that distal airways inflammation (airways with less than 2 mm diameter) is a prominent feature in this disease (Martin, 2002).

Conventionally, the diagnosis of asthma is based on history, particularly with the presence of a triad of wheeze, shortness of breath and cough (GINA Guidelines, 2008) [Click here to download a free copy of Global Initiative For Asthma]. Unfortunately such manifestations are variable.

For example, the use of serial peak expiratory flow rate or spirometry measurements as well as demonstrating airway reversibility with an increase of FEV1 of at least 12% from baseline 15 minutes post bronchodilator inhalation (GINA Guidelines, 2008); but such tests are based on demonstrating abnormal airway physiology and may often not be present in mild asthma (Smith et al, 2004). [Excellent article. Click here to download full text in pdf]

Other surrogate or direct markers such as methacholine or adenosine monophosphate challenge tests, as well as fiberoptic bronchoscopy utilizing bronchoalveolar lavage, are time consuming, invasive and uncomfortable for the patients.

Two recently proven methods to guide adjustment of asthma management are fraction of exhaled nitric oxide (FENO) and inducing sputum for eosinophilia.

Being a relatively new marker for asthma, NO was first described in the 1980s (Zeidler et al, 2004). It was initially known as endothelial derived relaxation factor (EDRF), as it was shown to be responsible for vasodilatation of arterioles (Furchgott & Zawadzki, 1980). Subsequent researches also show that nitric oxide (NO) plays a role in inflammation, immunity and neurotransmission (Zeidler et al, 2004).

NO is produced from the conversion of L-arginine to NO and citrulline by Nitric oxide synthase (NOS). Constitutive expression of NOS produces low level of NO in healthy lungs. Inducible nitric oxide synthase on the other hand, is responsible for the increased levels of NO produced in inflammatory states in the lung and is markedly upregulated by interferon-γ, tumor-necrosis factor-α, and interleukin-1β and downregulated by corticosteroids (Robbins et al, 2004).

FENO has been shown to be increased in proportion to the severity of bronchial wall inflammation (Payne et al, 2001), severity of airway hyperresponsiveness (Jones et al, 2001; Jatakanon et al, 1998) and its level has been shown to be reduced in a dose dependent manner (Kharitonov et al, 2002; Jones et al, 2002). Unlike induced-sputum analysis, FENO measurements are easy to perform, reproducible, and was highly accepted by patients (Kharitonov et al, 2003).

As mentioned, conventional tests, as mentioned above, are primarily based on demonstrating abnormal airway physiology, such as bronchial hyperresponsiveness. Therefore, these tests are not sensitive enough particularly in cases of mild asthma.

Unfortunately, although conventional tests may show normal results in such cases, it has been shown that, even in asymptomatic asthmatic patients with remission of symptoms of up to one year have been shown to have continued eosinophilic inflammation and bronchial hyperresponsiveness (van den Toorn et al, 2000; van den Toorn et al, 2001; Spallarossa et al, 2003). In such cases, FENO is particularly helpful, because it has high discirminatory power (Dupont et al, 2003; Malmberg et al, 2003; Deykin et al, 2002).

As mentioned, these conventional tests are also time consuming, and may require repeated measurements (for example, in cases of serial peak flow measurements). This may also affect patients' compliance (Smith et al, 2008). [Excellent article, click here to download the full text from New England Journal of Medicine (NEJM)]


References:
Busse WW, Lemanske RF, Jr. Asthma. N Engl J Med 2001; 344 (5):350-62.

Deykin A, Massaro AF, Drazen JM et al. Exhaled nitric oxide as a diagnostic test for asthma: online versus offline techniques and effect of flow rate. Am J Respir Crit Care Med 2002; 165 (12):1597-601.

Dupont LJ, Demedts MG, Verleden GM. Prospective evaluation of the validity of exhaled nitric oxide for the diagnosis of asthma. Chest 2003; 123 (3):751-6.

Furchgott RF, Zawadzki JV. The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine. Nature 1980; 288 (5789):373-6.

Jatakanon A, Lim S, Kharitonov SA et al. Correlation between exhaled nitric oxide, sputum eosinophils, and methacholine responsiveness in patients with mild asthma. Thorax 1998; 53 (2):91-5.

Jones SL, Kittelson J, Cowan JO et al. The predictive value of exhaled nitric oxide measurements in assessing changes in asthma control. Am J Respir Crit Care Med 2001; 164 (5):738-43.

Kharitonov SA, Gonio F, Kelly C et al. Reproducibility of exhaled nitric oxide measurements in healthy and asthmatic adults and children. Eur Respir J 2003; 21 (3):433-8.

Malmberg LP, Pelkonen AS, Haahtela T et al. Exhaled nitric oxide rather than lung function distinguishes preschool children with probable asthma. Thorax 2003; 58 (6):494-9.

Martin RJ. Therapeutic significance of distal airway inflammation in asthma. J Allergy Clin Immunol 2002; 109 (2 Suppl):S447-60.

Payne DN, Adcock IM, Wilson NM et al. Relationship between exhaled nitric oxide and mucosal eosinophilic inflammation in children with difficult asthma, after treatment with oral prednisolone. Am J Respir Crit Care Med 2001; 164 (8 Pt 1):1376-81.

Robbins RA, Barnes PJ, Springall DR, et al.: Expression of inducible nitric oxide in human lung epithelial cells. Biochem Biophys Res Commun 1994, 203:209-218.

Smith AD, Cowan JO, Filsell S et al. Diagnosing asthma: comparisons between exhaled nitric oxide measurements and conventional tests. Am J Respir Crit Care Med 2004; 169 (4):473-8.
(Click here to download)

Smith AD, Cowan JO, Brassett KP et al. Use of exhaled nitric oxide measurements to guide treatment in chronic asthma. N Engl J Med 2005; 352 (21):2163-73. (Click here to download)

Spallarossa D, Battistini E, Silvestri M et al. Steroid-naive adolescents with mild intermittent allergic asthma have airway hyperresponsiveness and elevated exhaled nitric oxide levels. J Asthma 2003; 40 (3):301-10.

van den Toorn LM, Overbeek SE, de Jongste JC et al. Airway inflammation is present during clinical remission of atopic asthma. Am J Respir Crit Care Med 2001; 164 (11):2107-13.

van den Toorn LM, Prins JB, Overbeek SE et al. Adolescents in clinical remission of atopic asthma have elevated exhaled nitric oxide levels and bronchial hyperresponsiveness. Am J Respir Crit Care Med 2000; 162 (3 Pt 1):953-7.

Zeidler MR, Kleerup EC, Tashkin DP. Exhaled nitric oxide in the assessment of asthma. Curr Opin Pulm Med 2004; 10 (1):31-6.

How "GOOGLE"able Are You?

As the world is getting smaller, flatter and more globalized, social media is the way to go in the near future.

Those who are not convinced, watch the video clip "Did You Know 4.0?" below:





You can read the detailed transcript of the video here.

Just to trigger your imagination:

This year (2009), traditional advertising revenue is in steep decline:

• Newspapers advertising is down 18.7%
• TV advertising is down 10.1%
• Radio advertising is down 11.7%
• Magazine advertising is down 14.8%

Meanwhile, digital advertising is growing rapidly:

• Mobile advertising is up 18.1%
• Web advertising is up 9.2%
• 47% of broadcast television viewers say they would pay for ad-less programming.

Myspace, Facebook, and YouTube collectively get 250 million unique visitors per month. None of these sites existed 6 years again.

In fact, the question today we should ask ourselves is 'HOW "GOOGLEABLE" are you?'.
It is part of our personal and professional branding in the online community.

One can test out one's online "googleability" by using the online ID Calculator here.

In fact, the webpage of that online calculator even goes to claim that "Today, if you don't show up in Google, you don't exist"

Nevertheless, I believe that social media participation by healthcare professionals are very fragmented. As highlighted in this blog story by Dr. V, physicians ought to follow one another on twitter for example, to create a loud, resounding voice. I like what he said, regarding the example of the vaccination. Here is what he said:

"60,000 is a number I reference when discussing physicians and social media. There are 60,000 members of the American Academy of Pediatrics. Every pediatrician fights vaccine misinformation, especially as they relate to autism. Consider the fact that the first two pages of a Google search for vaccines and autism are polluted with anti-vaccine propaganda driven by a loud, socially-savvy minority. If every AAP member wrote a myth-dispelling post concerning immunization just once a year, Google would be ruled by reason."

Of course, participating in social media ought to be tampered with a sense of professionalism, medical ethics and a conviction of one's professional responsibility to protect the patient's privacy. One should just take a look at this story of medical students posting pictures that compromised patient's privacy.

One of the reasons why this blog was set up is because I know emergency medicine in my country is still in its infancy and the niche area I can use to improve the development of emergency medicine in my country is through the cyber community.

Furthermore, most of my medical students today have a facebook profile, some have their own blogs, that they have been blogging about their ward experiences. Shouldn't we as doctors and lecturers do so?

Preventing Influenza Transmission: Is Surgical Mask Comparable To N95 Respirator?

In a new original article reported in JAMA this week (1st October 2009), a randomized trial was conducted to compare the effectiveness of surgical masks and N95 respirators to confer protection against influenza for healthcare workers. This article can be downloaded free here.

As many have known, transmission of influenza can occur by coughing or sneezing through the inhalation route of the infectious particles of variable size, possibly ranging from approximately 0.1 to 100 µm. Nevertheless, the exact nature of transmission of influenza that occurs in nonexperimental settings is not well understood yet.

However, although this is an important issue, especially in the wake of the A(H1N1) pandemic, there has been few comparative studies done on the different types of respiratory devices.

Examples of earlier studies on the effectiveness of respiratory devices:

1. Hand hygiene and face mask has been shown to be important to prevent household transmission in this study done in Hong Kong.
(Cowling BJ, Chan KH, Fang VJ; et al. Facemasks and hand hygiene to prevent influenza transmission in households: a randomized trial [published online August 3, 2009]. Ann Intern Med)

2. The use of masks and goggles was associated with a significant reduction of RSV illnesses in pediatric health care workers, according to this study.
(Agah R, Cherry JD, Garakian AJ, Chapin M. Respiratory syncytial virus (RSV) infection rate in personnel caring for children with RSV infections: routine isolation procedure vs routine procedure supplemented by use of masks and goggles. Am J Dis Child. 1987;141(6):695-697)


But in general, however, how best to protect healthcare workers against influenza remains unresolved.

In this new article, the randomized trial involving eight Ontario, Canada, tertiary care hospitals was conducted during the 2008–2009 winter influenza season.

Participants were 446 nurses who provided care to patients with febrile respiratory illness while working in emergency departments or inpatient medical or pediatric units.

Follow-up (including twice-weekly assessment for signs and symptoms of influenza, and laboratory testing of nasal specimens from participants with influenza-like illness) lasted from January 12 through April 23, 2009.

Influenza infection occurred in 50 nurses (23.6%) in the surgical mask group and in 48 (22.9%) in the N95 respirator group (absolute risk difference, –0.73%; 95% CI, –8.8% to 7.3%; P = .86)

In other words, surgical masks and N95 respirators provided healthcare workers with comparable protection against influenza.

In addition, no significant between-group differences were noted in the incidence of influenza-like illness or infections with respiratory syncytial virus, metapneumovirus, parainfluenza viruses, rhinovirus-enterovirus, or coronaviruses.

However, surgical mask should be properly worn. Download this guideline on wearing surgical mask.

99% of Our Malaysian Buildings Are Not Built to Withstand Earthquakes

In this blog post, I am doing something a little bit different. Rather than sending out case presentations or latest trials findings, I found three pieces of news from various news portal that interest me.

1. The most frightening news that I got is to know that 99% of our Malaysian buildings are not built to withstand earthquakes. The reason being Malaysia rarely experience earthquakes. This is indeed worrying especially for emergency physicians here.

Check out at: http://bit.ly/10vfp8

PENANG, Oct 12, – Less than one per cent of buildings in Malaysia are built according to specifications that take earthquakes into consideration, said Associate Professor Taksiah Abdul Majid, supervisor of Universiti Sains Malaysia (USM)’s Disaster Research Unit. Taksiah, who is a leading researcher in earthquakes, said from the unit’s research most buildings did not take the earthquake factor into consideration assuming that Malaysia was not exposed to the risk of earthquakes.

“Malaysia rarely experiences strong earthquakes and that factor causes many specifications for building construction to pay not much attention to earthquakes. “However, we cannot be complacent as Kuala Lumpur is just 300km from Sumatra, which frequently experiences strong earthquakes,” she said at a news conference at USM here today. She said among buildings that followed specifications related to earthquakes were the Kuala Lumpur Twin Towers, the Penang Bridge and the Komtar building here... [click to read more]

2. The second piece of news that interest me is that Singapore has planned to reduce specialist training time from 7 years to 5 years in total upon graduation. While that is not my concern, I was thinking...in Malaysia, probably a doctor would only start applying to do his specialty training after 5 years...hmm. But anyway, the news article below mentions some of the disadvantages of shortening the training time. [Click here to read more]

SINGAPORE - In a move to ramp up the medical expertise needed for Singapore's ageing population - and the increased chronic disease load expected - Singapore is looking at cutting the training time needed for its medical specialists from seven to five years......

Currently, doctors are selected for traineeship upon completion of their housemanship, which is a one-year compulsory training in the public hospitals. This is followed by a three-year posting to various hospital departments for exposure to varied patient types. At the end of the compulsory hospital rotations and training - and upon passing a postgraduate examination, they move on to a two- to four-year advanced speciality training before becoming Associate Consultants. For some specialities, this could mean a total of seven years of postgraduate training. Under the American system, Prof Chee said a doctor can go directly from medical school into a seamless residency programme of five to six years, with exposure to all the necessary disciplines.

But are there downsides to this reduction in training time? Speaking to MediaCorp, MP for Sembawang GRC, Dr Lim Wee Kiak, said any reduction is welcomed but one concern is that those under the proposed new system may not be as well-trained as their predecessors. Dr Lim, an ophthalmologist by training, said: "With a compressed training period, they may not see as many patients ... The challenge is to ensure that the residency programme is tight enough for the doctors to have enough opportunities to see all sorts of cases."

As for Dr Fatimah Lateef, MP for Marine Parade GRC, who has trained medical students and doctors for 16 years - the last 12 in emergency medicine - one concern is the maturity of the postgraduate students. Noting that "the pass rate is not high", Dr Fatimah said that even after seven years, some may not have the maturity to make "independent decisions". With reduced training time, she said: "We have to make sure there is sufficient dedicated time for those training the specialists to supervise them." Candidates would also have to take the initiative to learn beyond the lesson plans drawn up for them...........

3. Researchers in Singapore say that A(H1N1) virus infection is no different from seasonal flu in terms of its behavior, symptoms wise, etc. I have some reservations to buy into that as I personally think that it is still premature to make such conclusion.

Researchers say H1N1 virus no different from seasonal flu By Cheryl Lim, Channel NewsAsia | Posted: 14 October 2009 0025 hrs

SINGAPORE: Researchers have uncovered more insights into the behaviour of the H1N1 strain of influenza. On comparing the H1N1 strain of influenza and the seasonal flu, researchers said that the two flu strains affect patients with the same symptoms and body temperature at presentation.

These findings, from Tan Tock Seng Hospital, are based on studies on its first 70 H1N1 patients. "One of the things we also realised is that for those individuals who present early, and get treatment early, they can shorten the duration of virals recovered from the nose and the throat," said Associate Professor Leo Yee Sin, clinical director, Communicable Disease Centre, Tan Tock Seng Hospital.........

Continue reading,,,http://www.channelnewsasia.com/stories/singaporelocalnews/view/1011150/1/.html

I-Gel: The New Supraglottic Device. Will It Get To be Recomemnded As One of the Alternatives Airway in the Next Resus Guidelines?

The above image is linked from http://www.hospital-int.net/images/companies/1702/igel-airway-management-2b.jpg

We are seeing a promising new supraglottic device joining in the armamentarium of airway devices designed to be inserted as easy as possible, in the shortest possible time, and in a manner as secure and as good as endotracheal intubation in terms of its ability for prevention of aspiration.

I-gel is the new supraglottic device that is seeing positive results from clinical trials so far, and might even be advocated as one of the alternative option in advanced life support.

One study has shown that Pro-Seal LMA and igel were both faster to insert than the cLMA and offer additional benefits.

In another study, insertion success rate was shown to be 97%. Insertion was easy and performed at the first attempt in every patient. Mean seal pressure was 30 ± 7 cm H2O, and average peak pressure was 11 ± 3 cm H2O. The gastric tube was inserted in 100% of cases. Only one case of coughing and one mild sore throat occurred.

I-gel can be rapidly inserted in both manikins and patients by novice users and compares favourably to other supraglottic airways available.

In yet another study, median airway seal was 20 cmH2O (range 13–40) [another study shows that it is 30 cm H2O]. One case of regurgitation and partial aspiration occurred.

I-gel effectively conforms to the perilaryngeal anatomy despite the lack of an inflatable cuff and it consistently achieved proper positioning for supraglottic ventilation.

Click here for a list of the studies on I-gel.

Athough I-gel is currently not widely used, and not available in Malaysia, it has shown promising results, and agents may soon be swarming in promoting the device especially if this device really gets to be listed as a recommendation in the next resuscitation guidelines.

Disclaimer: I have no part in the company that sells I-gel, InterSurgical Ltd; neither am I affiliated to them but you can visit their homepage to download a copy of the I-gel instruction manual to better understand the simplicity and their features (also to watch a video on insertion).

Will Procalcitonin Become An Indispensable Diagnostic Tool To Guide Antibiotics Use in Respiratory Infections? A Step Closer Towards The Reality

From the results of a multicenter, randomized controlled trial reported in the September 9 issue of the Journal of the American Medical Association (JAMA), it seems probable that Procalcitonin (PCT) measurements may reduce rates of antibiotic use for lower respiratory tract infections (LRTIs).

Although procalcitonin is not routinely used in clinical practice in Malaysia, certainly as more and more data are available in the future, it may become an important diagnostic and prognostic adjunct.

Inappropriate antibiotic prescribing for lower respiratory tract infection (LRTI) is widespread and can promote bacterial resistance while increasing costs and incidence of drug-related adverse effects.

In that study, Schuetz P et al. from the ProHOSP Study Group, evaluated whether the use of a serum procalcitonin (PCT)-based algorithm could safely reduce antibiotic administration for LRTI (defined as community-acquired pneumonia, exacerbation of chronic obstructive pulmonary disease, or acute bronchitis).

The algorithm encouraged or discouraged antibiotic use according to different PCT cutoff values. They randomized 1359 consecutive adult patients who presented to six tertiary care hospital emergency departments in Switzerland with LRTI diagnosed by clinical and laboratory criteria to receive antibiotic administration according to the algorithm or standard guidelines.

The primary outcome of that study, i.e., incidence of adverse outcomes within 30 days (a composite of death, intensive care unit admission, disease-specific complications, and recurrent infection requiring antibiotics) did not differ significantly between the algorithm and standard guidelines groups (15.4% and 18.9%).

But the good news is that the mean duration of antibiotic exposure and the incidence of antibiotic-associated adverse effects were significantly lower in the algorithm group than in the standard guidelines group (5.7 vs. 8.7 days, respectively, and 19.8% vs. 28.1%, respectively).

Although LRTIs are responsible for more disease and death in the U.S. than any other infection, to date, clinical markers are inaccurate for distinguishing between bacterial and viral infection.

Procalcitonin is released in response to bacterial infection, correlates with severity of LRTI, and is rarely elevated in viral infections. (Note: PCT levels are usually low in viral infections, chronic inflammatory disorders or autoimmune processes whereas the PCT levels in sepsis are generally greater than 1-2 ng/mL and often reach values between 10 and 100 ng/mL, or considerably higher in individual cases, thus enabling the diagnostic differentiation between these various clinical conditions and a severe sepsis)

PCT has the greatest sensitivity (85%) and specificity (91%) for differentiating patients with SIRS from those with sepsis, when compared with IL-2, IL-6, IL-8, CRP and TNF-alpha (Click here to download a copy of the article).

Besides being highly specific increase in response to severe systemic bacterial infections and sepsis, another major advantage of Procalcitonin (PCT) compared to other parameters is its early rise in response to the infections. Thus, in septic conditions increased PCT levels can be observed 3-6 hours after infectious challenge.

This study demonstrates that a clinical decision rule based on PCT levels can appropriately diminish antibiotic use and help tailor duration of therapy without compromising patient safety.

Reference:
Schuetz P et al. Effect of procalcitonin-based guidelines vs standard guidelines on antibiotic use in lower respiratory tract infections: The ProHOSP randomized controlled trial. JAMA 2009 Sep 9; 302:1059.

Other references:
1. Christ-Crain M, Stolz D, Bingisser R; et al. Procalcitonin guidance of antibiotic therapy in community-acquired pneumonia: a randomized trial. Am J Respir Crit Care Med. 2006;174(1):84-93. Click here to download in pdf.

2. Nobre V, Harbarth S, Graf JD; et al. Use of procalcitonin to shorten antibiotic treatment duration in septic patients. Am J Respir Crit Care Med. 2008;177(5):498-505. Click here to download in pdf.

Can We Avoid Head CT scan in Some Pediatric Patients With Head Trauma?

In a multicenter trial published in Lancet recently, Kuppermann N et al. enrolled 42,412 children (age, ≤18 years) with mild head trauma (defined as Glasgow Coma Scale score >13) to derive and validate decision rules for two separate age groups:
- those below 2 years and
- those aged 2 years and above.

In that paper, the authors highlighted the need to identify pediatric patients with very low risk of clinically important brain injuries who might not need a CT scan after all:

1. 40 - 60% of those with traumatic brain injuries seen on CT scan are from this group of patients with minor head injuries or those with GCS 14 and 15.

2. But the converse is not true - less than 10% of those with minor head injuries show traumatic brain injuries

3. Furthermore, even if there are head trauma identified, injuries needing neurosurgery are very uncommon in children with GCS scores of 14 - 15

4. The risk of radiation exposure. Ionising radiation from CT scans can cause lethal malignancies. The estimated rate of lethal malignancies from CT is between 1 in 1000 to 1 in 5000 pediatric cranial CT.

But predictive models in such cases are not new. There have been predictive models to identify low risk patients where Head CT may probably be avoided. However, in that paper, it is stated that the problems with previous predictive models:

- are limited by small sample size
- lack of validation
- no independent assessment of preverbal children (less than 2 years old)

From that study, the authors identified that:

The Decision To Avoid CT in Children with Head Trauma could be made:

A. In Children less than 2 years old if
* Normal mental status
* No scalp hematoma except frontal hematoma
* LOC<5 seconds
* Non severe mechanisms of injuries (see below for the list)
* No palpable scalp fracture
* Normal behavior

B. In Children 2 years and above if
* Normal mental status
* No LOC
* No vomiting
* Non severe mechanisms of injuries (see below for the list)
* No signs of base of skull fracture
* No severe headache

Non severe mechanisms of injuries:
# death of a passenger in the accident
# ejection of patient from the vehicle
# rollover
# pedestrian or bicyclist without helmet struck by the vehicle
# fall more than 1.5 m for children above 2 years old and more than 0.9 m for children less than 2 years
# head struck by high impact object

In the validation group of 2216 children younger than 2 years, the rule had 100% sensitivity and negative predictive value. In the validation group of 6411 children 2 years and older, the rule had 96.8% sensitivity and 99.5% negative predictive value.

Using the list of features identified, the suggested algorithm for mild head trauma in that paper:
A. In Children less than 2 years old:
Step 1:
Is the patient with altered mental status OR a palpable skull fracture: If yes - CT;
If no, then proceed to Step 2

Step 2:
Is the patient has occipital or parietal or temporal scalp hematoma OR LOC 5 or more seconds OR severe mechanism of injury OR "not acting normally" as per parent:
if yes: (use clinical judgement with the following in mind)
Observation vs CT on the basis of other clinical features include
- physician experience
- multiple versus isolated findings
- worsening symptoms of signs after emergency department observation
- age of less than 3 months
- parental preference


if not
- then CT SCAN IS NOT RECOMMENDED

B. In Children 2 years or older

Step 1:
Is the patient with altered mental status OR other signs of basilar skull #: if yes - CT

If no, then proceed to Step 2:

Step 2:
Is the patient with history of LOC OR vomiting OR severe mechanism of injury OR severe headache:

If yes, again Observation vs CT on the basis of other clinical factors including:
- physician experience
- multiple versus isolated findings (see note below)
- worsening symptoms or signs after emergency department observation
- parental preference

If no, then CT SCAN IS NOT RECOMMENDED.

Note: Patients with certain isolated findings (i.e. without other findings suggestive of traumatic brain injury) such as
- isolated LOC
- isolated headache
- isolated vomiting
- certain types of isolated scalp hematomas in infants older than 3 months
have risk of clinical important TBI (traumatic brain injuries) of less than 1%.

In general, if risk of clinically important TBI is exceedingly low, lower than risk of CT induced malignancies, then CT scans are not indicated.

In short, while using this rule may identify pediatric patients at very low risk of having clinically important TBI when ALL of the CRITERIA are fulfilled; the converse is not true. Doctors still have to use their own clinical judgment to see which patients they would order a CT scan. Nevertheless, as always, extra caution is still advisable in children younger than 3 months, in whom clinical evaluation may be less reliable.


Reference:
Kuppermann N et al. Identification of children at very low risk of clinically-important brain injuries after head trauma: A prospective cohort study. Lancet 2009 Sep 15; [e-pub ahead of print]. (http://dx.doi.org/10.1016/S0140-6736(09)61558-0)