Ventilator-associated tracheobronchitis

Health Care, Medicine, Social Health Community 372 Comments

Ventilator-associated tracheobronchitis (VAT) has the same clinical implications as ventilator-associated pneumonia (VAP). An observational study of 28 patients with VAT and 83 patients with VAP [1] showed that VAT groups had a similar length of intensive care unit stay, length of hospital stay, duration of mechanical ventilation, survival rate to discharge, need for tracheostomy, and need for antibiotics.

Ventilator induced diaphragmatic atrophy

Controlled mechanical ventilation can lead to a very rapid type of disuse atrophy involving the diaphragmatic muscle fibers. An observational study found that diaphragmatic strength decreased progressively during mechanical ventilation and that long-term (>24 hours) mechanical ventilation was associated with diaphragmatic muscle injury, atrophy, and proteolysis compared to short-term mechanical ventilation (2-3 hours).(2)

Starting enteral nutrition in a patient on ventilator

Starting enteral nutrition with a low infusion rate improves tolerability, compared to initiation at the target rate. A randomized study of 200 mechanically ventilated patients showed that enteral feeding ( at the target rate or at 10 mL/hr for six days before being incrementally increased to the target rate) showed no differences in mortality, ventilator-free days, or ICU-free days, but the group that began at the target rate had more episodes of elevated gastric residual volumes and a trend toward more diarrhea. (3)

References
1. Dallas J, Skrupky L, Abebe N, et al. Ventilator-associated tracheobronchitis in a mixed surgical and medical ICU population. Chest 2011;139:513-8.
2. Jaber S, Petrof BJ, Jung B, et al. Rapidly progressive diaphragmatic weakness and injury during mechanical ventilation in humans. Am J Respir Crit Care Med 2011;183:364-71.
3. Rice TW, Mogan S, Hays MA, et al. Randomized trial of initial trophic versus full-energy enteral nutrition in mechanically ventilated patients with acute respiratory failure. Crit Care Med 2011;39:967-74.

New Delhi metallo-beta-lactamase (NDM-1)

Health Care, Medicine, Social Health Community 1,531 Comments

Enterobacteriaceae isolates carrying a novel MBL gene, the New Delhi metallo-beta-lactamase (NDM-1) was first described in December 2009 in India with Klebsiella pneumoniae (1). Later, it was described in patients who had traveled to and undergone procedures in India and Pakistan (2). Cases were also reported in Asia, Europe, and North America (2-4). Isolates have also included E. coli and Enterobacter cloacae (2).

Risk factors

  1. Recent treatment with carbapenem
  2. Indwelling urinary or venous catheters
  3. Severe illness (5)
  4. NDM-1 can inactivate all beta-lactams except aztreonam.

Salient points

1.    It is an important emerging resistant pathogen (6).

2.     NDM1 isolates are susceptible to colistin or tigecycline

3.    The susceptibility is short-lived.

4.     NDM-1 has been identified in public water supplies in India (7)

References

  1. Yong D, Toleman MA, Giske CG, et al. Characterization of a new metallo-beta-lactamase gene, bla(NDM-1), and a novel erythromycin esterase gene carried on a unique genetic structure in Klebsiella pneumoniae sequence type 14 from India. Antimicrob Agents Chemother 2009;53:5046.
  2. Kumarasamy KK, Toleman MA, Walsh TR, et al. Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study. Lancet Infect Dis 2010;10:597.
  3. Centers for Disease Control and Prevention (CDC). Detection of Enterobacteriaceae isolates carrying metallo-beta-lactamase – United States, 2010. MMWR Morb Mortal Wkly Rep 2010;59:750.
  4. Sidjabat H, Nimmo GR, Walsh TR, et al. Carbapenem resistance in Klebsiella pneumoniae due to the New Delhi Metallo-β-lactamase. Clin Infect Dis 2011;52:481.
  5. Deshpande P, Shetty A, Kapadia F, et al. New Delhi metallo 1: have carbapenems met their doom? Clin Infect Dis 2010;51:1222.
  6. Nordmann P, Poirel L, Toleman MA, Walsh TR. Does broad-spectrum {beta}-lactam resistance due to NDM-1 herald the end of the antibiotic era for treatment of infections caused by Gram-negative bacteria? J Antimicrob Chemother 2011;66:689.
  7. Walsh TR, Weeks J, Livermore DM, Toleman MA. Dissemination of NDM-1 positive bacteria in the New Delhi environment and its implications for human health: an environmental point prevalence study. Lancet Infect Dis 2011;11:355.

Another Bomb Blast in Delhi

Health Care, Social Health Community 405 Comments

A powerful bomb exploded outside Delhi High Court gate number 5 on Wednesday morning. The blast took place at around 10.15 am. It left 11 people dead and more than 100 injured. This is the second such incident at the High Court this year.

Half of all early casualties seek medical care over first hour. To know the total number of casualties, double this number after one hour. This formula is often used by the media to predict the tolls. It is also useful to predict demand for care and resource needs.

The most severely injured arrive after the less injured who self–transport to the closest hospitals, so always expect upside down triage.

It is important that we as doctors know how bomb blast cause injuries in order to tackle the repercussions of bomb blasts. Bomb blast injuries can be categorized into four types:

  • Primary blast injuries are a direct result of the impact of the over pressurized blast wave on the body. It involves injuries to the hollow gas–filled organs like the lungs, ear drum or intestines leading to their rupture.
  • Secondary blast injuries occur due to flying debris and bomb fragments causing penetration or penetrating injuries to organs such as eyes.
  • Tertiary blast injuries occur when individuals are thrown by the blast wind leading to fractures due to the fall.
  • Quaternary blast injuries are due to direct effect of burn or crush injuries.

The most important aspect is not to waste energies and resources on patients with non-serious injuries.

Look for eardrum rupture and signs of respiratory imbalance. Their absence indicates a non–serious injury.

  • If the ear drums are intact, the patient can be discharged with first–aid treatment.
  • If ear drum is ruptured, immediately do an X–ray chest. Keep the patient under observation for eight hours as primary blast injuries may have a delayed presentation.

Hence, otoscopic ear exam can be used as a screening procedure for triage. Decreased oxygen saturation on pulse oximetry signals early blast lung injury, even before symptoms become apparent.

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