icuroom.net January 2008 Archive

2008-01-31T16:10:00.000-08:00

Thursday January 31, 2008
Etomidate controversy continues !!

Use of Etomidate in intubation remained controversial due to its ability to cause adrenal insufficiency (AI) but still commonly used due to its excellent hemodynamic profile !

See this recent retrospective registry study published in Archives of surgery 1: Increased Risk of Adrenal Insufficiency Following Etomidate Exposure in Critically Injured Patients

Interventions: Cosyntropin stimulation testing (CST), in which response was defined as an increase of 9 µg/dL (248 nmol/L) or more in cortisol level.

Results: In 137 patients, CST was performed; 83 (60.6%) were nonresponders and 54 (39.4%) were responders.

3 independent factors in non-responders were

Rates of hemorrhagic shock on admission
requirement of vasopressor support and
etomidate exposure

Age, sex, race, trauma mechanism, injury severity score, and revised trauma score were not statistically different between the groups. Rates of sepsis/septic shock, mechanical ventilation, and mortality were also similar between the 2 groups.

Conclusions: Exposure to etomidate is a modifiable risk factor for the development of AI in this sample of critically injured patients.

Reference: click to get abstract / article if available

1. Increased Risk of Adrenal Insufficiency Following Etomidate Exposure in Critically Injured Patients - Arch Surg. 2008;143(1):62-67

2008-01-29T21:02:00.000-08:00

Wednesday January 30, 2008
Abbreviation Errors

Q: Which abbreviation cause the most confusion and largest numbers of error ?

A: QD = once daily

In one recent study "The Impact of Abbreviations on Patient Safety", published in The Joint Commission Journal on Quality and Patient Safety, found that "QD=Once daily" cause 43.1 % of errors out of all abbreviation errors.
From 2004 through 2006 a total of 29,974 medication errors were reported to the MEDMARX program from, attributable to abbreviation use. The top 5 confusing abbreviations were

"QD” (once daily) = 43.1%
“U” (units) = 13.1%,
“cc” (mL) = 12.6%,
“MSO4” or “MS” (morphine sulfate) = (9.7%), and
decimal errors = 3.7%

The total number of medication errors were 643,151, over study period (2004-2006) !

Related previous Pearls:

LASA drugs
"Five Rights"
38,000 medication errors in 4 years - only in ICUs !!
ICU satellite pharmacy Preventing intra-venous (IV) drip errors

Reference: click to get abstract / article if available

1. The Impact of Abbreviations on Patient Safety - The Joint Commission Journal on Quality and Patient Safety, September 2007 Volume 33 Number 9

2008-01-29T08:11:00.000-08:00

Tuesday January 29, 2008
Protamine induced Pulmonary Vasoconstriction !

Scenario: 48 year old male with coronary artery disease has been taken for CABG. At the end, protamine reversal was instituted. After few minutes of protamine infusion start, the PAP (pulmonary artery pressure) suddenly increased to 90/40 mm Hg. The protamine was discontinued. PAP noted to return to normal. The protamine was restarted but the PAP again rapidly increased to 85/37 mm Hg, and patient became hypotensive.

Answer: Protamine induced acute pulmonary hypertension.

Mechanism of action: Complement activation, leading to thromboxane A2 generation causing acute pulmonary hypertension 2.

Treatment is application of inhaled Nitric Oxide and hemodynamic support as required. Interestingly, Protamine can be restarted if needed to complete surgery under protection of inhaled NO ! By using NO, a full reversal dose of protamine can be successfully administered to a patient. Nitric Oxide can be weaned in next 24 hours after surgery.

Alternatives to protamine for heparin reversal, such as heparinase or recombinant platelet factor 4 can be applied but are usually unavailable.

Reference: click to get abstract / article if available

1. The Use of Nitric Oxide for Managing Catastrophic Pulmonary Vasoconstriction Arising from Protamine Administration Anesth Analg 1999;88:505

2. Lessons from studying an infrequent event: adverse hemodynamic response associated with protamine reversal of heparin anticoagulation. J Cardiothorac Anesth 1989;3:99–107

2008-01-28T20:28:00.000-08:00

Monday January 28, 2008
Effect of Prone Positoning (PP) on Right Ventricle in ARDS !

Prone position in ARDS though remains very fascinating in theory but remain very hard to deliver clinically due to logistics issue. Dangers of losing tube, IVs and overwhelming need of staff are various factors of its unpopularity. Specifically developed prone beds (like Rotoprone) are available but still not widely used due to cost and various reasons as above.

One interesting aspect of prone therapy is its benefit in acute cor pulmonale which may develops in severe ARDS patients. One recently published study from france looked into effect of prone positioning into unloading of the right ventricle in Severe ARDS.

42 ARDS patients treated by PP to correct severe oxygenation impairment (P/F ratio, less than 100 mm Hg).

21 patients had acute cor pulmonale (defined by RV enlargement associated with septal dyskinesia),
21 patients had a normal RV.

RV function was evaluated by bedside transesophageal echocardiography, before and after 18 hours of prone position ventilation.

Results:

PP was accompanied by a significant decrease in airway pressure and PaCO2 in both groups
In cor pulmonale group, PP produced a significant decrease in mean RV enlargement after 18 h of PP and a significant reduction in mean septal dyskinesia after 18 h of PP

Conclusion:

In the most severe forms of ARDS, PP was an efficient means of controlling RV pressure overload.

Reference: click to get abstract

Prone Positioning Unloads the Right Ventricle in Severe ARDS - Chest.2007; 132: 1440-1446

2008-01-27T10:54:00.000-08:00

Sunday January 27, 2008
Bedside tip ! - CPR on patient with IABP

If patient requires CPR who is on Intra-Aortic Baloon Pump (IABP) - do not switch off IABP. Switch from "ECG trigger" to "Pressure trigger". IABP during CPR improves cerebral and cardiac blood flow.

With CPR, on "pressure trigger", an arterial pressure tracing should be generated on console/screen and if the console is not recognising the arterial pressure tracing, it means chest compressions may not be adequate.

Complete guide of IABP: Concepts of Counterpulsation Therapy System - (Datascope)

2008-01-26T15:34:00.000-08:00

Saturday January 26, 2008
Bedside tip !

Scenario: 48 year old male with end stage renal disease and dialysis dependent admitted from ER with septic shock. Infectious Disease consult recommends to remove Tessio catheter (dialysis) as that could be the most probable source of infection. Patient is a known 'line nightmare' due to multiple previous dialysis catheter procedures. What would be your plan of action knowing that Tessio could be your only line access and patient is hemodynamically unstable ?

Answer: Do not remove catheter unless you have another access in place.

This is true that in case of suspected line infection, all central lines should be removed and new lines be inserted with 'fresh stick' but in situation like above, where line becomes only 'life line', it is not advisable to remove it and end up with 'no access'.

Attempt to obtain line under sonography and if no success, consult vascular surgery or interventional radiology to have alternate line before removing the suspected infected line.

2008-01-25T12:10:00.000-08:00

Friday January 25, 2008
Drug-Eluting Stents vs. CABG in Multivessel Coronary Disease

Very important obsevational study published from New York in this week issue of The New England Journal of Medicine, comparing Drug-Eluting Stents vs. Coronary-Artery Bypass Grafting in Multivessel Coronary Disease 1.

Patients compared: CABG (N = 7437) vs Stent (N = 9963)

The end points of the study: Death in the hospital or within 30 days after treatment and death, death or myocardial infarction, and revascularization up to 18 months after treatment.

Results:
CABG was associated with lower 18-month rates of death and of death or myocardial infarction both for patients with three-vessel disease and for patients with two-vessel disease.
Patients undergoing CABG also had lower rates of repeat revascularization.
Conclusions: For patients with multivessel disease, CABG continues to be associated with lower mortality rates than does treatment with drug-eluting stents and is also associated with lower rates of death or myocardial infarction and repeat revascularization.

Arguments against study in editorial of NEJM (Joseph P. Carrozza, Jr., M.D.):

1. "......For example, dementia is not a covariate in this risk-adjustment model and would be likely to influence a clinician to choose PCIinstead of CABG. When confounders are associated with an increased risk of the measured outcome (e.g., death), bias becomes clear. Factors precluding CABG include coexisting conditions that are linked to poor prognosis (e.g., dementia), whereas those precluding PCI are often lesion- based (e.g., chronic total occlusion) and have a lesser effect on prognosis after CABG. Thus, the presence of these unmeasured confounders may bias the outcome in favor of CABG".

2. "....It is important to remember that in this observational study, the physician, and sometimes the patient, chose the treatment and thus introduced selection bias. In a randomized design,patients must qualify for both treatments and assignment is by chance. This allows a purer comparison of two treatments but has practical limitations. Is it appropriate to remove physicianand patient preferences from decision makingwhen they are such important features of “realworld” medicine?"

3. "Patients were enrolled before widespread use of extended dual antiplatelet therapy as prophylaxis against latestent thrombosis".

4. "The mean follow-up times for both treatments were only 19 months,a period that captures the majority of clinical events related to the major hazards of stenting — thrombosis and restenosis — but does not include events driven by atherosclerosis of saphenous- vein grafts, a process that begins several years after surgery."

Final words in editorial:

"The New York State registries affirm that CABG remains the standard of care for patients who require multivessel coronary revascularization. However, stents may be an alternative for patients at high risk for surgical complications or when an informed patient chooses a less invasive option".

References: click to get abstract / article if available

1. Drug-Eluting Stents vs. Coronary-Artery Bypass Grafting in Multivessel Coronary Disease - Volume 358:331-341, Number 4, Jan. 24 2008

2. Drug-Eluting Stents — Pushing the Envelope beyond the Labels? - Editorial, n engl j med 358;4 www.nejm.org january 24, 2008

2008-01-24T19:55:00.000-08:00

Thursday January 24, 2008
Selective digestive decontamination (SDD) - a controversy !

Selective digestive decontamination (SDD) has been used as a prophylactic measure to prevent nosocomial infections in critically ill patients. But it continues to remain controversial.

Arguments against: wide spread use of this strategy are the fear of emergence of multi-resistance organisms and its cost.

Arguments in favour: is the reference of availability of 54 randomized, controlled trials with seven meta-analyses showing a significant reduction of infectious morbidity and mortality 1. Also, there are evidences that fear of wide spread emergence of multi-resistance organisms is OVER-EXAGGERATED 2, 3. The newer, even more potent systemic antimicrobials fail to clear MRSA and Pseudomonas aeruginosa from the gut, because the salivary and fecal concentrations are not lethal. The addition of enteral antimicrobials probably eliminates the source, controlling resistant mutants in the gut flora.

Very recent updated International guidelines for management of severe sepsis and septic shock from Surviving Sepsis Campaign recommends not to use of SDD specifically in severe sepsis. But please note that the guidelines group was evenly split on the issue of SDD, with equal numbers in favor and against recommending the use of SDD. The final consensus on use of SDD in severe sepsis was achieved only at the last nominal committee meeting 4.

Out of many recommended regimens, one is a combination of oral and enteral polymyxin E, tobramycin and amphotericin B four times daily until discharge from the ICU. In addition, an initial four-day course of iv cefotaxime was given. When applicable, antibiotic paste and suppositories were used for tracheostomy sites and blind-bowel loops respectively. Finally, nebulized polymyxin E or amphotericin B was administered to eradicate documented colonization of the tracheobronchial tree 2.

References: click to get abstract / article if available

1. Antibiotic prophylaxis to reduce respiratory tract infections and mortality in adults receiving intensive care (Cochrane Review). In: The Cochrane Library, issue 1. Chichester, John Wiley & Sons, 2004

2. Selective digestive decontamination decreases mortality and morbidity in the intensive care - Canadian Journal of Anesthesia 51:737-739 (2004)

3. Surviving Sepsis Campaign Guidelines: Selective Decontamination of the Digestive Tract Still Neglected - letter to editor, Critical Care Medicine:Volume 33(2)February 2005pp 462-463

4. Surviving Sepsis Campaign: International guidelines for management of severe sepsis and septic shock: 2008 - Critical Care Medicine:Volume 36(1)January 2008pp 296-327

2008-01-23T21:47:00.000-08:00

Wednesday January 23, 2008
Updated international guidelines for management of severe sepsis and septic shock - 2008

The updated Surviving Sepsis Campaign: International guidelines for management of severe sepsis and septic shock is now available.

Read here

Few important updates are:

1. Intravenous antibiotic therapy be started as early as possible and within the first hour of recognition of septic shock (1B) and severe sepsis without septic shock (1D)

2. Epinephrine be the first chosen alternative agent in septic shock that is poorly responsive to norepinephrine or dopamine

3. ACTH stimulation test not be used to identify the subset of adults with septic shock who should receive hydrocortisone

4. Xigris: adult patients with severe sepsis and low risk of death do not receive rhAPC (grade 1A). Adult patients with sepsis-induced organ dysfunction associated with a clinical assessment of high risk of death, most of whom will have APACHE II more than / = 25 or multiple organ failure, receive rhAPC if there are no contraindications (grade 2B except for patients within 30 days of surgery, for whom it is grade 2C).

5. Once tissue hypoperfusion has resolved (initial resuscitation) and in the absence of extenuating circumstances, such as myocardial ischemia, severe hypoxemia, acute hemorrhage, cyanotic heart disease, or lactic acidosis red blood cell transfusion to target a hemoglobin of 7.0-9.0 g/dL in adults

6. Erythropoietin not be used as a specific treatment of anemia associated with severe sepsis

7. Not to use pulmonary artery catheter for patients with ALI/ARDS in routine use
8. Targeting glucose levels to the less than150 mg/dL range

9. Not to use sodium bicarbonate for the purpose of improving hemodynamics or reducing vasopressor requirements in patients with hypoperfusion-induced lactic acidemia with pH more than / = 7.15

10. Not to use of SDD (Selective Digestive Tract Decontamination) specifically in severe sepsis - The guidelines group was evenly split on the issue of SDD, with equal numbers weakly in favor and against recommending the use of SDD. The final consensus on use of SDD in severe sepsis was achieved at the last nominal committee meeting

Also you can hear R. Phillip Dellinger M.D., one of the key person involved in drafting of these guidelines here, from Surviving Sepsis Campaign - North American Summit - Denver 2007

Reference: click to get abstract

1. Surviving Sepsis Campaign: International guidelines for management of severe sepsis and septic shock: 2008 - Critical Care Medicine:Volume 36(1)January 2008pp 296-327

2008-01-22T06:31:00.000-08:00

Tuesday January 22, 2008

Q: Why (Dexamethasone) decadron is not a good choice of steroid in septic shock unless untill absolutely necessary?

Answer: Reasons which render dexamethasone a poor choice in ICU particularly in sepsis are:

1. It has very minimal (almost negilgible) mineralocorticoid activity. Advantage of performing ACTH stimulation test, while on decadron is there but again its no more recommended to perform in septic shock per updated guidelines of Surviving Sepsis Campaign 1. It is suggested to give IV hydrocortisone to adult septic shock patients if blood pressure remains poorly responsive to fluid resuscitation and vasopressor therapy (grade 2C) - without ACTH stimulation test. Potency of Hydrocortisone and Dexamethasone is 20:1 - means 1 mg of dexamethasone is equal to 20 mg of hydrocortisone.

2. It has prolog half life of 36-54 hours. In updated guidelines of Surviving Sepsis Campaign 1, it is Grade 2B recommendation that patients with septic shock should not receive dexamethasone if hydrocortisone is available. As dexamethaxone has no mineralcorticoid activity, in case if used, should be use with florinef (fludrocortisone).

3. Dexamethasone can lead to immediate and prolonged suppression of the hypothalamic-pituitary-adrenal axis after administration 2.

Reference: click to get abstract

1. Surviving Sepsis Campaign: International guidelines for management of severe sepsis and septic shock: 2008 - Critical Care Medicine:Volume 36(1)January 2008pp 296-327
2. The hypothalamic-pituitary-adrenal axis in critical illness: Response to dexamethasone and corticotropin-releasing hormone. J Clin Endocrinol Metab 1993; 77:151-156

2008-01-21T20:27:00.000-08:00

Monday January 21, 2008
Acid-base website !

See this easy to navigate and calculate acid-base disorders website. Simply compute your numbers and have mutiple/overlapping disorder in few seconds instead of lengthy calculations.

Calculator can be find here

The physiological basis of acid-base disorder is discussed in detail. The online text is available free for HTML version (pdf has charge). Book has 9 chapters including

Body Fluids,
Goals, Definitions, and Basic Principles,
The Simplest Acid-Base System: Pure Water,
Strong Ions and the Strong Ion Difference,
Weak electrolytes and buffers,
Strong ions plus carbon dioxide (isolated, intact interstitial fluid),
Strong ions plus carbon dioxide plus weak acid: isolated blood plasma and isolated intracellular fluid,
Interactions between body fluids and
Whole-body acid-base balance

Book can be read here

(we added calculator in our calculators section - see side bar)

2008-01-20T22:28:00.000-08:00

Sunday January 20, 2008
Resistant Sickle cell crisis !

Scenario: 28 year old male with history of sickle cell crisis presented with priapism. 6 hours past and despite adequate hydration and analgesia, there is no relief ! What is your next option ?

Answer: In case of priapism, you have 2 options. Either call an urologist for aspiration of corpus cavernosum or consult a hematologist for exchange blood transfusion.

Exchange blood transfusion in sickle cell crisis should be consider in following situations:

No relief in crisis despite adequate hydration and analgesia
Any sign of stroke
Pregnancy
Prophylactic exchange transfusion prior to major surgery. A single exchange transfusion reduces the risk of complications from the general anaesthetic and surgery
C/O loss of vision in one eye or visual symptoms
Unresolved painful erection of the penis (priapism)

References: Click to get abstracts / articles

1. Anemia, Sickle Cell, emedicine.com

2008-01-19T18:00:00.000-08:00

Saturday January 19, 2008
Combo for Hepato-renal !!

There is enough literature to support the idea that combo of "octreotide and midodrine" along with "albumin" may improve renal function in hepato-renal syndrome. In this combo, some studies have included TIPS (transjugular intrahepatic portosystemic stent shunt) also. Reports appear to be encouraging atlest in terms of improvement of renal function.

Doses used in the ballpark of midodrine up to 12.5 mg tid, octreotide 20 mg IM once, albumin 150 mg q weekly. But can be increase more frequently in ICU setting, if required.

The idea behind use of this combo is the simple hypothesis that refractory ascites and hepatorenal syndrome are mediated in part by diminished circulatory volume and that treatment with midodrine, octreotide and albumin can improve renal and patient outcomes by restoring effective circulating volume and systemic perfusion.

Also, this combo is under investigation as an alternative to large volume paracentesis !

References: Click to get abstracts / articles

1. Octreotide/Midodrine Therapy Significantly Improves Renal Function and 30-Day Survival in Patients with Type 1 Hepatorenal Syndrome - Digestive Diseases and Sciences, Volume 52, Number 3 / March, 2007

2. The Use of Drugs to Improve Kidney Function in Patients With Liver and Kidney Dysfunction - Clinical trial # NCT00240045, clinicaltrials.gov

3. Midodrine, octreotide, albumin, and TIPS in selected patients with cirrhosis and type 1 hepatorenal syndrome - Hepatology, Volume 40, Issue 1 , Pages 55 - 64

4. Alternatives to Large Volume Paracentesis Study (LVP) - clinical trial # NCT00530959, clinicaltrials.gov

2008-01-18T07:42:00.000-08:00

Friday January 18, 2008
Revisiting Weaning ! - parameters to watch in SBT

Dr. Neil MacIntyre in his recent editorial (Critical Care Medicine) 1, simply put the following 7 measurements to watch in SBT (spontaneous Breathing Trial) beside RSBI - rapid shallow breathing index - f/VT.

Objective measurements

1. Gas exchange acceptability

Spo2 ≥85-90%,
Po2 ≥50-60 torr,
pH ≥7.32,
increase in Paco2 of ≤10 torr

2. Hemodynamic stability

heart rate <120-140>
heart rate not changed by >20%,
systolic blood pressure <180-200>90,
blood pressure not changed by >20%,
no pressors required

3. Stable ventilatory pattern e.g.,
respiratory rate ≤30-35 breaths/min,
respiratory rate not changed by >50%

Subjective clinical assessments
No change in mental status (e.g., somnolence, coma, agitation, anxiety)
No onset or worsening of discomfort
No diaphoresis
No signs of increased work of breathing (use of accessory respiratory muscles, thoracoabdominal paradox)

* Editorial is written in respone to article in same issue from Tobin and Jubran: Meta-analysis under the spotlight: Focused on a meta-analysis of ventilator weaning 2.

References: click to get article

1. Ventilator discontinuation process: Evidence and guidelines , Critical Care Medicine:Volume 36(1)January 2008pp 329-330

2. Meta-analysis under the spotlight: Focused on a meta-analysis of ventilator weaning , Critical Care Medicine. 36(1):1-7, January 2008. Tobin, Martin J. MD; Jubran, Amal MD

2008-01-17T06:00:00.000-08:00
Thursday January 17, 2008
Oglivie's syndrome

Q: Which electrolyte abnormality may prevent Neostigmine from resolving Oglivie's syndrome (Acute colonic pseudo-obstruction)?

A; Potassium

Acute colonic pseudo-obstruction or Ogilvie syndrome, is an acute large bowel obstruction with no evidence of mechanical colonic obstruction. It is said to be due to invasion and destruction of the splanchnic nerves, superior mesenteric ganglion, and celiac nerve plexus.Neostigmine, an acetylcholinesterase inhibitor, increases acetylcholine concentrations at the enteric nervous system neuromuscular junctions, enabling smooth muscle to contract. Neostigmine is given as intravenous, 2 mg over 5 minutes. A repeat dosage may be given if necessary. Side effects of neostigmine include sweating, salivation, bradycardia, hypotension, and bronchospasm. Due to possible bradycardia, atropine should be available at bedside. The neostigmine is eliminated by kidney and should be use with caution in renal failure.An anecdotal report indicates that patients with hypokalemia, may not respond to neostigmine. 1

References: click to get article
Acute colonic pseudo-obstruction (Ogilvie's syndrome) in critical care unit - Year : 2004, Volume : 8, Issue : 1, Page : 43-45

2008-01-16T20:06:00.000-08:00
Wednesday January 16, 2008

Scenario: They ask you in ICU to evaluate this 22 yo previously healthy pt. after a craniotomy for GSW, who was supposed to get extubated this am but unexpectedly his pre-extubation paO2 is only 60. Also, "something happened" with his ETT. It was reported to you that earlier RT has to push it back. Patient was left on CPAP.

You look at the pt. and see the ETT goes across his mouth from one side to the other and is at 23 cm at the lips. He appears to be biting on the ETT a little and is a little sleepy but cooperative. SpO2 is 95 % on 40 % FiO2. You consider the cuff might be broken and try inflating it and it seems to be taking quite a bit of air. Eventually it seems to stay firm but you think there might be a very slow leak, like there is sometimes from minuscule holes. You think there may be some atelectasis that needs to be opened so you try the Ambu bag but the bag cannot hold the lungs inflated ! Actually you hear the air coming out the mouth. And as you inflate the cuff a little more still and the patient desaturates:

what happened ?

Answer: Patient had cough up the ET tube and is above the cords.

The pre-extubation paO2 was low as he was getting some room air from around the ETT by a Venturi effect. The T-E fistula is another possibility. As patient was extubated his saturation jumped to 100% - indeed he was ready for extubation. Patient desaturated with ambu bag as he got hypoxic he bit the ETT closed. Also, as you occluded the air coming in from around the cuff (balloon) - by inflating more air inside - he lost the venturi effect too.

Note: Objective of above question is to raise awareness about importance of secure and patent airway. You may feel this is a classic (or common & easy) scenario though but even seasoned intensivist can get scared and confused a little when facing it.

Moral of the story: Airway is no place to fool around (as in above scenario RT by pushing ETT inward and later physician by inflating more air in cuff and by ambu bagging - made situation worse).

Above pearl is contributed by :

Ivan Hronek MD at SFMC, Los Angeles
ivanhronek@yahoo.com

2008-01-15T14:03:00.000-08:00
Tuesday January 15, 2008

Scenario: 79 year old male, nursing home resident, with abdominal pain, nausea, vomiting, and diarrhea is admitted to ICU with significant hemodynamic instability. While reviewing previous discharge summaries, you found multiple reports of positive stool for 'C.Diff.' with successful treatment with 'flagyl'. You started patient on appropriate broad range antibiotics including flagyl. Patient responded well to treatment and is getting transfer out of ICU after 2 days but before transfer you received strange call from nurse - that patient's urine is black ! Will you hold the transfer ?

Answer: NO

Metronidazole (Flagyl) induced change of urine color.

Black urine is a rare but benign side effect of Flagyl. The actual metabolite responsible for this phenomenon has not been positively identified yet but fortunately it has no clinical significance.

Related article: The Significance of Abnormal Urine Color

(Martha K. Terris, M.D., Assistant Professor of Urology, Chief of Urology, Veterans Affairs Palo Alto Health Care System)

2008-01-14T19:17:00.000-08:00
Monday January 14, 2008
Cefepime in renal failure patients

Cefepime is dialysable. In patients on CVVHD (Continuous venovenous haemodiafiltration), no dosage adjustment for cefepime is required and the dosage regime as with normal renal function should be administered.

But in patients on HD (hemodialysis), dose of 1 gram every 24 hours is recommended. Dose of cefepime is advisable after the session on HD days as cefepime is dialysable.

Please take note of danger of not adjusting cefepime in HD patients. Cefepime-related neurotoxicity is now well documented and could be a real danger causing mild disorientation, waxing and waning mental state, generalized tonic-clonic seizures or even coma.

Reference: click to get abstract / article

1. Cefepime-related neurotoxicity in a haemodialysis patient - Nephrol Dial Transplant (1999) 14: 2265-2266

2008-01-13T13:58:00.000-08:00
Sunday January 13, 2008
Back to basics !! - trivia on sunday

Though various scales and calculators are now available online and handy at bedside, but being an intensivist its important to atleast remember few basic formulae. Judge yourself. Ask yourself out of following 5 basic formulae, which one you can recall right.

1. Body Surface Area
2. Systemic Vascular Resistance
3. A-a Gradient
4. Static Compliance
5. Creatinine Clearence

Answers:

1. BSA = Sqrt of [Wt (kgs) x Ht (cms)/3600]

2. SVR = [(MAP -CVP)/CO] 80 dynes/sec x cm-5 Normal: 900-1200 dynes/sec x cm-5

3. A-a Gradient = [(FiO2 /100) (760 - 47)] - (PaCO2 /0.8) - PaO2 Normal is less than 10 torr
4. Static Compliance = VT/Pplateau - PEEP Normal >60 mL/cm H2O

5. Creatinine Clearence = 140-Age x Weight (Kg)/ 72 xSerum creatinine ( x 0.85 for feamles)

2008-01-12T06:44:00.000-08:00

Saturday January 12, 2008
Heparin and Insulin - mixup? - FDA warning

2008-01-11T14:48:00.000-08:00
Friday January 11, 2008
Changeovers of vasoactive drug infusion pumps

Hemodynamic instability during the changeover of vasoactive infusion pump (CVIP) is a common site in ICUs. Interesting article published very recently in Critical Care 1 in which the impact of a "quick change method" of CVIP (2 syringes) was assessed and compared with regular (single syringe) method.

Study was done (compared) in 2 phases.

Phase 1: In this phase, nurses were free to choose the method of changeover of CVIP they usually practice.

Phase 2: In this phase, strategy called “quick change method” is applied. using two syringe drivers. This consisted loading the new infusion with a new line into a new syringe pump, and priming the line when the running infusion was about to finish. Nurses started the pump and chose a high flow rate until a drop of vasoactive drug appeared on the end of the line, in order to avoid a start up delay. Next, they programmed the pump to same rate and setting as the previous infusion. After that, they removed the cap from the spare port of the three-way stopcock and connected it the new infusion pump. Then, they turned the three-way stopcock on to the new infusion, which closed the lumen of the old infusion. Lastly, they had to disconnect the old infusion and put a cap on the new spare port.

913 changeovers of infusion pumps were evaluated: 435 in phase 1 and 478 in phase 2.

Results: The frequency of incidents was significantly reduced in phase 2 (5.9%, n=28) versus phase 1 (17.8%, n=78) with 98% of incidents were blood pressure variations.

References: click to get abstract / article

1. Changeovers of vasoactive drug infusion pumps: impact of a quality improvement program - pdf file, Critical Care 2007, 11:R133

2008-01-10T14:26:00.000-08:00
Thursday January 10, 2008

Q; Which beta-blocker is prone to cause life-threatening hyperkalemia particularly in kidney transplant patient?

A; Labetalol

One of the relatively unknow and fortunately benign side effect of beta-blockers is hyperkalemia. Most of the hyperkalemia is benign particularly with cardio-selective b-blockers. But life-threatening hyperkalemia may occur after IV dose of labetalol, particularly in patients with chronic renal failure, hemodialysis patients and post kidney transplant patients.

References: click to get abstract / article

1. Labetalol-Induced Hyperkalemia in Renal Transplant Recipients , American Journal of Nephrology 2002;22:347-351

2. Possible Metoprolol-Induced Hyperkalemia, Journal of Pharmacy Practice, Vol. 19, No. 5, 320-325 (2006)

2008-01-09T06:36:00.000-08:00
Wednesday January 9, 2008

Q; Which 2 very commonly used medicines, physicians prescribe simultaneously and probably reflexly - but they cancel each other effects ?

A; β-blockers and Dobutamine (while trying to control tachycardia of dobutamine by b-blockers)

Dobutamine is a selective β1 adrenergic agonist and its effect get neutralize by β-blockers.

Atenolol, Esmolol, Metoprolol are β1 blockers
Carvedilol, Labetalol and Nadolol are β1, β2 blockers

2008-01-08T10:39:00.000-08:00
Tuesday January 8, 2008
VATS conversion to a standard thoracotomy

Q; In how many cases VATS (Video-Assisted Thoracic Surgery)require intraoperative conversion to a standard thoracotomy ?

A; In approximately 20% of patients undergoing VATS, intraoperative conversion to a standard thoracotomy will be necessary for any of several reasons, including extensive pleural adhesions and pulmonary lesions that cannot be located thoracoscopically or that necessitate a more extensive resection than can be accomplished endosurgically.

(so keep fingers cross once you send your patient to OR)

2008-01-07T16:03:00.000-08:00
Monday January 7, 2008
Mucomyst - does it work ? - yes, no, yes, no ?
Helps kidney or lung or liver ?

Since landmark 2000 article of NEJM 1 on benefit of antioxidant, N-acetylcysteine (mucomyst) on prevention of acute renal failure in many clinically stress situations, it has almost became a standard of practice. Since than though many studies failed to show its benefit and strictly from evidence based medicine, it has yet to prove its role !

This month, another study published from Italy in Critical Care Medicine 2, on benefit of N-acetylcysteine for prevention of acute renal failure in patients with chronic renal insufficiency undergoing cardiac surgery.

Randomized, placebo-controlled, prospective study of 254 consecutive patients with chronic renal insufficiency (estimated cr. cl. less than or = 60 mL/min) undergoing elective cardiac surgery wwas done. Patients were randomized into 2 groups

to receive N-acetylcysteine (n = 129). Patients of the N-acetylcysteine group received four boluses of intravenous N-acetylcysteine (1200 mg every 12 hrs, starting immediately before cardiac surgery).
or placebo (n = 125)

Postoperative acute renal failure is defined as more than 25% increase in serum creatinine from baseline.

Results:

Acute renal failure occurred in occurred in 52% of control patients and 40% of N-acetylcysteine-treated patients (p = .06)
In-hospital mortality and need for renal replacement therapy were not affected by N-acetylcysteine
N-acetylcysteine-treated patients required less days of mechanical ventilation prolonged for >48 hrs (3% vs. 18%; p < .001)
N-acetylcysteine-treated patients had lower incidence of prolonged stay in intensive care unit stay, defined as more than 4 days (13% vs. 33%; p < .001)

Conclusions:

Though IV mucomust does not clearly prevent postoperative acute renal failure in patients with renal insufficiency undergoing cardiac surgery, it suggests a positive effect of NAC on pulmonary function that influences a patient's clinical course by having lower days of mechanical ventilation and so lower ICU-LOS !

Editors' comment: Use it !

Related previous pearls:

Double the dose of mucomyst? ,
Contrast induced Nephropathy and
Preventing contrast-Induced Nephropathy - use of sodium bicarbonate

References: click to get abstract / article

1. Prevention of Radiographic-Contrast-Agent–Induced Reductions in Renal Function by Acetylcysteine - N Engl J Med 343:180, July 20, 2000
2. N-acetylcysteine for prevention of acute renal failure in patients with chronic renal insufficiency undergoing cardiac surgery: A prospective, randomized, clinical trial - Critical Care Medicine. 36(1):81-86, January 2008

2008-01-06T21:15:00.000-08:00
Sunday January 6, 2008
Levaquin dosing in renal failure

Q; What's the dose adjustment of Levaquin (levofloxacin) in Hemodialysis or Chronic Ambulatory Peritoneal Dialysis (CAPD) as well as CVVHD patients?

A; For Hemodialysis, CAPD and with creatinine clearance less than 20 mL/min, dose of levofloxacin is 250 mg per 48 hours. In HD patients, dose should be given after HD session.

For CVVHD levaquin should be given as 250 mg/day as there is some clearance via CVVHD.

References: click to get abstract / article

1. Levaquin - Rxlist.com
2. Pharmacokinetics of Levofloxacin and Ciprofloxacin during Continuous - Renal Replacement Therapy in Critically Ill Patients (pdf) - ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, Oct. 2001, p. 2949–295

2008-01-05T15:57:00.000-08:00

Saturday January 5, 2008
Ok to fresh frozen plasma but male-donor-only please !!

In July 2003 the English Blood Service stopped using female donor plasma for the manufacture of fresh frozen plasma (FFP). Transfusion-related acute lung injury (TRALI), due to plasma from female donors containing antileucocyte antibodies, is allegedly a contributor to the development of acute lung injury (ALI). To confirm above hypothesis, a before-and-after, observational (single-centre) study was performed on 211 consecutive patients undergoing open repair of a ruptured AAA over 8 years period (1998 to 2006).

Primary outcome was development of ALI (PaO2/FiO2 < color="#003333">Secondary outcomes were time to extubation, and survival at 30 days.

Results
Primary outcome: There was significantly less ALI following the change to male-only FFP (36% before vs 21% after, P = 0.042). Secondary outcomes: were not statistically different between groups.
Patients with ALI in either group had a poorer 30-day survival (59% vs 80%, P = 0.005).
Conclusion:
Exclusion of female-donor FFP was associated with a statistically significant reduction in the incidence of ALI (in patients undergoing repair of a ruptured AAA).

Reference: click to get abstract / article
1. The effect of male-donor-only fresh frozen plasma on the incidence of acute lung injury following ruptured abdominal aortic aneurysm repair - Freeman Hospital and National Blood Service, Newcastle upon Tyne, UK - from 27th International Symposium on Intensive Care and Emergency Medicine Brussels, Belgium. 27–30 March 2007, Critical Care 2007, 11(Suppl 2):P374

2008-01-04T19:02:00.000-08:00
Friday January 4, 2008
5 things to eye ball on TEG (Thromboelastogram)

Please also see our previous pearl What is TEG

Read with diagram below along with normal values

r - reaction time - from start of test to initial clot formation. Prolonged with clotting factor deficiencies and heparin.

a - Ang or alpha angle - it assesses rate of clot formation and decreased in the presence of clotting factor deficiencies, platelet dysfunction, thrombocytopenia, and hypofibrinogenaemia.

K - is a measure of time from beginning of clot formation until the amplitude of thromboelastogram reaches 20 mm, and represents the dynamics of clot formation.

MA - maximum amplitude - the widest point of the traceing on vertical or Y-axis . It represents maximum clot strength and is reduced with platelet dysfunction.

LY 30 or lysis 30 - is the percentage decrease in amplitude 30 min after MA, measures the degree of fibrinolysis. (see bending curves in b below)

References: click to get abstract / article
1. Thromboelastography / Thromboelastometry (pdf file) (ref: Clin. Lab. Haem. 2005, 27, 81–90)
2. Management of coagulation during cardiopulmonary bypass (pdf file) (ref: Continuing Education in Anaesthesia, Critical Care & Pain Volume 7 Number 6 2007)

2008-01-03T16:46:00.000-08:00
Thursday January 3, 2008
Anticoagulation Medications - sites of action

A very simple diagram to show at what level basic 4 groups of anticoagulation medicines strike their effect.

Heparins - UFH and LMWH - are antithrombin

Warfarin - Warfarin inhibits the synthesis of biologically-active forms of the vitamin K-dependent clotting factors II, VII, IX and X, as well as the regulatory factors protein C, protein S, and protein Z.

Direct thrombin inhibitors (DTIs) - Hirudin, Lepirudin, Bivalirudin, Argatroban etc. - are a new class of anticoagulants that bind directly to thrombin and block its interaction with its substrates.

Thrombolytics - streptokinase, urokinase, alteplase, rtPA, reteplase, tenecteplase - works by activating the enzyme plasminogen, which clears the cross-linked fibrin mesh.

2008-01-02T02:52:00.000-08:00
Wednesday January 2, 2008
Procedure video - Proper opening of mouth for intubation

2008-01-01T13:33:00.000-08:00
Tuesday January 1, 2008