Friday October 9, 2009
Increases in Endotracheal Tube Resistance Are Unpredictable Relative to Duration of Intubation


Background: Accumulated secretions after intubation can affect the resistance of an endotracheal tube (ETT). Our objective was to measure extubated patient tubes and size-matched controls to evaluate differences in resistance.

Methods: New ETTs, with internal diameters of 7.0 through 8.5 mm, were tested as controls to establish the resistance of each size group as measured by pressure drop. Measurements were obtained using a mass flowmeter and pressure transducer. Pressure drop was measured at three flow rates.

Seventy-one patient ETTs were evaluated after extubation by an identical method and compared with controls.

Results:

• In each control group, pressure drop was tightly clustered with low variation and no overlap between sizes.
• A total of 73 to 79% of the patient ETTs had a pressure drop of more than 3 SDs of size-matched controls at all flow rates.
• Pressure drop in 48 to 56% (across three flow rates) of extubated tubes was equivalent to the next smaller size of controls.
• At 60 and 90 L/min, 10% and 15% of patient tubes, respectively, had the pressure drop of a control tube three sizes smaller.
• The pressure drop was unpredictable relative to the duration of intubation.

Conclusions:

• Organized secretions can significantly increase resistance as measured by the pressure drop of ETTs.
• The degree of change was highly variable, occurs in all sizes, and was unrelated to the duration of intubation.
• The performance of an ETT may be comparable to new tubes one to four sizes smaller.
• This may impact the tolerance of ventilator weaning.
  
  
  

References: Click to get abstract/article


Increases in Endotracheal Tube Resistance Are Unpredictable Relative to Duration of Intubation - CHEST October 2009 vol. 136 no. 4 1006-1013

Thursday October 8, 2009
Hemodialysis in Salicylate overdose with normal level

Hemodialysis is recommended in salicylate overdose patients with a level at or above 100 mg/dL (cut it to half if history suggest chronic ingestion). But if there is any sign of neurological manifestation, dialysis is indicated despite normal level.
Salicylate cause "neuroglycopenia" (lower CNS glucose level) despite normal serum glucose. As patient gets more and more acidotic, salicylate enters CNS and by direct effect cause neuroglycopenia.

7 indications of Hemodialysis in Salicylate poisoning

1. Mental status change
2. Pulmonary edema
3. Cerebral edema
4. Associated or with renal failure
5. Level at or above 100 mg/dL(half if chronic ingestion)
6. If fluid overload prevents alkalinization.
7. Patient continue to deteriorate clinically.
   
   

References: Click to get abstract/article

1. Toxicity, Salicylate - please register free at emedicine.com

2.An evidence based flowchart to guide the management of acute salicylate (aspirin) overdose -Emerg Med J 2002; 19:206-209

Wednesday October 7, 2009
Vasoconstrictor extravasation

Antidote for vasoconstrictor extravasation in skin and tissues (dopamine, epinephrine, or norepinephrine) is PHENTOLAMINE. Infiltrate 5-15 mg of PHENTOLAMINE in 10 ml of normal saline into the area of extravasation as soon as possible. Treatment may be applied and effective up to 12 hours post extravasation of vasoconstrictor. Keep yourself ready for fluid bolus post treatment.

Mechanism of action: Phentolamine is a nonspecific alpha-adrenergic blocking agent which inhibits vasoconstriction and allow improved blood circulation through the affected area.


References: Click to get abstract or article

1. Treating Extravasation Injuries - extravasation.org
2. The use of phentolamine in the prevention of dopamine-induced tissue extravasation - J Crit Care 1998 Mar;13(1):13-20

Tuesday October 6, 2009
Sympathetic Storming

Sympathetic storming after traumatic brain injury remains one of the most dramatic clinical scene particularly in neurological units. It occurs due to uncontrolled sympathetic surge with a diminish or unmatch parasympathetic response. Acording to Baguley criteria 5 out of the 7 clinical features should be present -

tachycardia,
tachypnea,
hyperthermia,
hypertension,
dystonia,
posturing, and
diaphoresis

Various agents have been used for treatment (see review article below) but haloperidol may worsen the symptoms.Dr. Blackman and coll. coined the term "PAID" - paroxysmal autonomic instability with dystonia- in Archives of Neurology March 2004.



References: click to get abstract/article

1. Dysautonomia after traumatic brain injury: a forgotten syndrome? - J Neurol Neurosurg Psychiatry 1999;67:39-43 ( July )
2. Paroxysmal autonomic instability with dystonia (PAID) - Arch Neurol. October 2004;61:1625.
3. Paroxysmal Autonomic Instability with Dystonia After Brain Injury - Arch. Neurol. March 2004;61:321-328

Monday October 5, 2009
Patients who code while on pressors have low chance of survival

Following pearl contributed by:

Tony Halat, MD
Clinical Instructor in Medicine Department of Medicine,
The Methodist Hospital
Weill Medical College, Cornell University



A small retrospective study looked at the outcome of patients who code in the ICU, including those who were on pressors prior to the code.

In this group of patients only 17% of all those who coded survived to discharge and only 4% of those already on vasopressors at the time of code survived. Interestingly the patients comprising the 4% all had underlying conditions amenable to intervention (myocardial infarction, aortic dissection).

The study concluded that the administration of vasopressors prior to the code strongly predicted non survival.




Reference: click to get article

Outcomes of cardiopulmonary resuscitation for patients on vasopressors or inotropes: A pilot study - Journa of Critical Care - Volume 24, Issue 3, Pages 415-418 (September 2009),

Sunday October 4, 2009
Call for dialysis in Lithium overdose

Call for Hemodialysis in Lithium toxicity is "clinical" depending on symptoms particularly neurological symptoms such as myoclonus, seizure, confusion or coma. There is no laboratory cutoff value as patient with chronic exposure to lithium may show clinical signs at much lower value. Also some recent data favors CVVHD (or HD followed by CVVHD) as it showed to prevent rebound of lithium serum concentration.

To dialyse or not to dialyse… - pwr point presentation - S. Gosselin, MD




Reference:

HD followed by continuous hemofiltration..: Am J Kidney Dis. 2001 May;37(5):1044-7

Saturday, October 3 2009
Propofol and Green urine

Propofol infusion is noticed to turn colour of urine green. It is a benign potential side effect of Propofol. Recognition of this side effect is important as it averts unnecessary further workup and limits medical expenditures.