May 2007 Archive

2007-05-31T14:49:00.000-06:00

Thursday May 31, 2007
Intensive Intraoperative Insulin Therapy versus Conventional Glucose Management during Cardiac Surgery

Since we are getting obsessive about tight control of blood glucose, concerns have been expressed about potential hypoglycemia. Many studies have shown that hypoglycemia during "tight" blood glucose control is a real danger with significant morbidity and mortality.

One recent study from Mayo Clinic, Rochester, MN compared intensive intraoperative insulin therapy with conventional glucose management during cardiac surgery. Patients were randomly assigned to tight glucose control (80-100 mg/dL) with continuous insulin infusion) or conventional treatment (n = 201).

Patients in the conventional treatment group were given insulin during surgery if glucose levels were greater than 200 mg/dL.
Both groups were treated with insulin infusion to maintain normoglycemia after surgery.

Results:
Eighty two of 185 patients (44%) in the intensive treatment group and 86 of 186 patients (46%) in the conventional treatment group had an event.
More deaths (4 deaths vs. 0 deaths) and strokes (8 strokes vs. 1 strokes) occurred in the intensive treatment group.

Study concluded that Intensive insulin therapy during cardiac surgery does not reduce perioperative death or morbidity. The increased incidence of death and stroke in the intensive treatment group raises concern about routine implementation of this intervention.

Reference: click to get abstract/article

Intensive Intraoperative Insulin Therapy versus Conventional Glucose Management during Cardiac Surgery, A Randomized Trial, Annals of internal Medicine, 20 February 2007 Volume 146 Issue 4 Pages 233-243

2007-05-30T09:35:00.000-06:00

Wednesday May 30, 2007
Digoxin Toxicity

Q: Once patient receive Digoxin Fragmented Antibody (DIGIFAB or Digibind), how frequent digoxin level should be measured ?

A: Digoxin level after giving Digibind will rise and will remain distorted for about 7 days. This is due to ability of Digibind to pull all of the digoxin into blood stream. These are inactive fragments and not toxic. There is no need to follow Dig level after administration of Digibind as it will be erroneously high and misleading.

2007-05-29T07:46:00.000-06:00

Tuesday May 29, 2007
Mix for Norepinepherine

Do you know that.....

NOREPINEPHRINE (LEVOPHED) is less stable in normal saline (loose its potency from oxidation). It is preferred to be mix in dextrose as the dextrose protects against oxidation of the norepinephrine and keep it active and stable.

2007-05-28T16:30:00.000-06:00

Monday May 28, 2007
Impact of delayed transfer of critically ill patients from emergency department to ICU

This is well known to Critical Care practitioners that critically ill patients does not desired treatment, if they continue to 'boarder' in emergency department. A very important study published this month in Criticare Care Medicine 1 regarding Impact of delayed transfer of critically ill patients from the emergency department to the intensive care unit.

50,322 patients were divided into two groups: emergency department boarding more than/= 6 hrs (delayed n=1036) vs. emergency department boarding less than 6 hrs. (nondelayed n=49,286). Main outcomes were ICU and hospital survival and ICU and hospital length of stay.

Results:
the median hospital length of stay was 7.0 (delayed) vs. 6.0 days (nondelayed).
ICU mortality was 10.7% (delayed) vs. 8.4% (nondelayed).
In-hospital mortality was 17.4% (delayed) vs. 12.9% (nondelayed).

Study concluded that, Critically ill emergency department patients with a more than/= 6-hr delay in intensive care unit transfer had increased hospital length of stay and higher intensive care unit and hospital mortality.

As said in discussion, the various factors which led to relatively poor outcome in ED 'boarders' icludes busy nature of ED practice, which entails simultaneous responsibilities for numerous patients of varying severities of illness, ED physicians and nurses may not be able to provide the focused one-on-one care that a critically ill patient may require, ED overcrowding and high patient acuity relative to the clinical staffing of the ED. ICU is a clinical environment that, by definition, enables close attention to the critically ill and allows for expeditious recognition of physiologic change and sudden deterioration, the ED under most circumstances is neither designed nor staffed to provide extended longitudinal care for the critically ill patient. It is also possible that there may be a different level of critical care expertise among the physicians and nurses who care for the patients who await ICU transfer, compared with the critical care expertise of the practitioners in the ICU setting.

Reference: click to get abstract

Impact of delayed transfer of critically ill patients from the emergency department to the intensive care unit - Critical Care Medicine. 35(6):1477-1483, June 2007.

2007-05-26T22:53:00.000-06:00

Sunday May 27, 2007
Little history of ICU

First designated area for critical care patients was established in 1958 by Peter Safar (1924 - 2003, also knows as Father of modern CPR), at Baltimore City Hospital USA, where he was Chief of Anesthesiology. Initially, the name was "Urgency & Emergency" room. First official Critical Care protocol was ABC (Airway, Breathing, and Circulation). The first Critical Care Residency was established in 1962 at the University of Pittsburgh.

Related site: The Safar Center for Resuscitation Research

Related previous pearl: Beyond CPR - EPR

2007-05-26T02:57:00.000-06:00

Saturday May 26, 2007
Bedside trick - suspecting tracheal aspiration !

One quick method of suspecting tracheal aspiration or atleast ruling out tracheal aspiration is checking glucose concentration by regular bedside glucose meters. A glucose concentration of more than 20 mg/dl of bloodless tracheal aspirate doesn't confirm but atleast enhance the suspicion of tracheal aspiration .Though literature is full of conflicting data for this method but still it is a very quick, effective and easy way of suspecting or ruling out tracheal aspiration.

References: click to get abstracts / articles

1. Clinical implications of the glucose test strip method for early detection of pulmonary aspiration in nasogastric tube- fed patients - Taehan Kanho Hakhoe Chi. 2004 Dec;34(7):1215-23
2. Comparison of blue dye visualization and glucose oxidase test strip methods for detecting pulmonary aspiration of enteral feedings in intubated adults - Chest, Vol 103, 117-121
3. Glucose content of tracheal aspirates: Implications for the detection of tube feeding aspiration. Crit Care Med 1994; 22:1557-1562
4. Glucose Content of Tracheal Aspirates - Letter to the Editor - Critical Care Medicine: Volume 23(8) August 1995 pp 1451-1452

2007-05-25T13:44:00.000-06:00

Friday May 25, 2007
One lung ventilation with Univent® Endotracheal Tube

There are many situations, where you may prefer only one lung to be ventilated like in pulmonary hemorrhage where you may like to block one lung to prevent the soiling of ther lung. In such instances, Univent® Endotracheal Tube could be of good value which can be quickly placed at bedside.

Tube is a regular endotracheal tube but has a extra lumen for bronchial blocker which can be advanced blindly (easily if right lung need to be blocked) or under bronchoscope guidance, and inflating the baloon cuff. For left side placement, rotating the blocker or preferably entire Univent® ETT with side of blocker towards left shown to have help in placement.

Another advantage is to ventilate via blocker tube lumen, so it can also be used as a guide in difficult intubation (like bougie) or in expected difficult ETT changes.

2007-05-24T09:36:00.000-06:00

Thursday May 24, 2007
Restless Legs syndrome

Restless legs syndrome is a common condition in non-intubated patients which may get aggravated by ICU enviroment. Major factors associated with Restless Leg Syndrome in ICU are
Iron-deficiency anemia
Peripheral neuropathy
Withdrawal from vasodilator drugs and sedatives
Cigarette smoking, alcohol and caffeine withdrawal
Various drugs including phenytoin, antidepressant drugs, H2 blockers, lithium, beta-blockers and antipsychotics
Hypomagnesemia
Renal insufficiency (uremia)

Various pharmacological agents have been described and used with success including benzodiazepines, carbamazepine and clonidine. In ICU situation, one useful drug in this regard is Ropinirole which is a Dopamine agonist. One of the effect of Ropinirole is heavy sleepiness, which can be use as a bonus benefit in ICU. Dose can be initiated from .25 mg PO QHS upto 4 mg PO QHS.

References: (click to get abstract)

1. Restless Legs Syndrome: Detection and Management in Primary Care - NATIONAL HEART, LUNG, AND BLOOD INSTITUTE WORKING GROUP ON RESTLESS LEGS SYNDROME - Vol. 62/No. 1 (July 1, 2000) - American Family Physician.

2. Ropinirole is effective in the treatment of restless legs syndrome. TREAT RLS 2: a 12-week, double-blind, randomized, parallel-group, placebo-controlled study - Mov Disord. 2004 Dec;19(12):1414-23.

2007-05-23T15:46:00.000-06:00

Wednesday May 23, 2007
Avandia's controversy

This week The New England Journal of Medicine has early published an online (for paper print due on June 14, 2007), meta-analysis of 42 trials with more than 24 weeks of exposure with drug Rosiglitazone (avandia). 15,560 patients were randomly assigned to treatment regimens that included rosiglitazone, and 12,283 were assigned to comparator groups with regimens that did not include Avandia 1, 2.

Results showed that in the rosiglitazone group, as compared with the control group, the odds ratio for myocardial infarction was 1.43 (P=0.03), and the odds ratio for death from cardiovascular causes was 1.64 (P=0.06).

But makers of Avandia GlaxoSmithKline promptly rejected the results of meta-analysis with strong references from other studies (like ADOPT 4 , DREAM 5 and RECORD 6 studies) showing no increase in cardivascular events 3.

As controversy has created so much media attention that FDA issued a statement which can be read here

Previous related pearl: Avandia associated exacerbation of CHF

References: click to get abstract/article

1. Effect of Rosiglitazone on the Risk of Myocardial Infarction and Death from Cardiovascular Causes - Article published at www.nejm.org May 21, 2007, due to print on june 14, 2007
2. Rosiglitazone and Cardiovascular Risk - editorial, published at www.nejm.org May 21, 2007, due to print on june 14, 2007
3. response from GlaxoSmithKline at avandia.com
4. A Diabetes Outcome Progression Trial (ADOPT), Diabetes Care 25:1737-1743, 2002
5. DREAM (Diabetes REduction Assessment with ramipril and rosiglitazone Medication) Trial Investigators; - Lancet. 2006 Sep 23;368(9541):1096-105
6. Rosiglitazone Evaluated for Cardiac Outcomes and Regulation of Glycaemia in Diabetes (RECORD): study design and protocol. Diabetologia. 2005 Sep;48(9):1726-35.

2007-05-22T11:46:00.000-06:00

Tuesday May 22, 2007

Often intensivist receive calls regarding issues which are usually not expected from critical care unit. One such situation is cerumen (ear wax) ! - Scenario taken from true instance from one of our editors' call.

Scenario: 62 year old male admitted with community acquired pneumonia and responding well with treatment. Patient continue to complaint of right ear pain. On examination patient noted to have cerumen impaction. Patient is already on broad spectrum antibiotics. You ordered cerumenex (Triethanolamine polypeptide). You received call from nurse that pharmacy substituted cerumenex with Docusate sodium or colace (stool softener) and needs your approval. What you think?

Answer: This is true that Docusate sodium is a very effective alternative to facilitate the removal of cerumen. Mechanism of action is same as for stool softener that it helps water or saline to mix with the hardened secretions and produce a softer cerumen which drained easily. Instill 1 ml and keep head to keep solution inside canal for 10 to 15 minutes and than let it drain.

References: click to get abstract/article

1. Ceruminolytic effects of docusate sodium: a randomized, controlled trial. Ann Emerg Med. 2000 Sep;36(3):228-32.

2. Docusate Sodium for Use as a Ceruminolytic Agent. Amer Fam Phys. 2001 Mar;63(5):947.

3. How does liquid docusate sodium (Colace) compare with triethanolamine polypeptide as a ceruminolytic for acute earwax removal? Journ of Fam Pract. 2000 Dec;49(12):1076.

4. Ear drops for the removal of ear wax - cochran reviews

2007-05-21T11:04:00.000-06:00

Monday May 21, 2007
Passive Leg Raising or Raising HOB to determine volume status

As we are getting more and more tangled with technology, unfortunately we are losing simple bedside maneuvers which were once integral part of physical examination.

CVP (central venous pressure) is a great way to determine volume status but even before central line get place, simple tricks at bedside may give assessment of volume status and may begin management even earlier. If blood pressure improves by just passively raising legs for 2-4 minutes or blood pressure drop by raising head of bed (HOB) to 45 degree, patient is probably hypovolumic.

See references, where these tests have been validated in clinical trials.

References: click to get abstract/article

1. Changes in BP Induced by Passive Leg Raising Predict Response to Fluid Loading in Critically Ill Patients - Chest. 2002;121:1245-1252.)

2. Passive leg raising predicts fluid responsiveness in the critically ill - Critical Care Medicine. 34(5):1402-1407, May 2006

3. Passive leg raising-induced changes in mean radial artery pressure can be used to assess preload dependence - poster from 27th International Symposium on Intensive Care and Emergency Medicine, Brussels, Belgium. 27–30 March 2007, Critical Care 2007, 11(Suppl 2):P307

2007-05-20T01:48:00.000-06:00

Sunday May 20, 2007
Free International Cardiology Internet Congress

Registration to participate in the the Fifth Virtual Congress of Cardiology - QCVC, organized by the Argentine Federation of Cardiology - is now open. The Congress will take place from September 1st to November 30th, 2007. The Argentine Federation of Cardiology - FAC organizes every two years, International Congresses of Cardiology by the Internet. They are characterized by a high scientific level and low cost for participants.

In last Virtual Congress of Cardiology (2005) 18,185 registrants from 128 countries participated. Access to the Fifth Virtual Congress of Cardiology will be made by a simple connection to the Internet. The lectures, reports, abstracts and brief communications will be published in Web pages. Opinions and questions will be sent by e-mail to discuss the respective forums and there will be on-line discussions in real time by scheduled chats. Everything that is treated in the Congress will remain permanently published on the Web. The Newsletter (Spanish, Portuguese, and English) will be edited weekly and sent to all the registrants throughout the three months of the Congress.

Click here to register or visit http://www.fac.org.ar/qcvc

Congress will have 21 thematic Units

Arrhythmias and Electrophysiology
Basic Research
Bioengineering - Medical Informatics
Cardiomyopathy
Cardiovascular Interventionism
Cardiovascular Nursing
Cardiovascular Pharmacology
Cardiovascular Surgery
Cerebral and Peripheral Vascular Diseases
Chagas' Disease
Echocardiography
Epidemiology and Cardiovascular Prevention
Genetics
Heart Failure
Hypertension
Ischemic Heart Disease
Nuclear Cardiology
Pediatric Cardiology
Sports Cardiology
Technicians in Cardiology
Transdisciplinary Cardiology

2007-05-19T12:14:00.000-06:00

Saturday May 19, 2007
Blood substitutes

Though blood substitutes are not yet approved in USA but are now in use in other parts of the world. In this regard 2 products are worth mentioning.

1. Hemopure : is a Bovine derived blood substitute and has already been approved for use in adult patients in South Africa.

2. Polyheme: is a human derived blood substitute and Phase III trial in united states completed in July 2006 1 for its role in for hemorrhagic shock following traumatic injuries. But there are unconfirmed media reports of increase coronary events in study 5.

Blood substitutes are solutions of chemically modified human or bovine hemoglobin which restores lost blood volume and can be given as rapid, massive infusion. One unit is equal to one unit of pRBC and can be given wide open.

Advantages: Does not require typing or cross-matching before infusion and so far found not to cause transfusion reactions. Shelf life of over 12 months (ciruclation time is 1-2 days) and does not require refrigeration. Bovine based Hemopure has been said acceptable for use in Jehovah's Witnesses (?).

Disadvantages: No evidence based data available yet. Concerns raised regarding mad cow disease in bovine based Hemopure !

References: Click to get abstract/article

1. Safety and Efficacy of PolyHeme(R) in Hemorrhagic Shock Following Traumatic Injuries Beginning in the Pre-Hospital Setting - clinicaltrials.gov
2. Watchtower Approves HemoPure for Jehovah's Witnesses - ajwrb.org
3. Effect of Hemopure® on Prothrombin Time and Activated Partial Thromboplastin Time on Seven Coagulation Analyzers, - Clinical Chemistry. 1997;43:1792
4. PolyHeme - American College of Surgeons at facs.org
5. PolyHeme Lawsuit - polyhemelawsuit.com

2007-05-18T15:58:00.001-06:00

Friday May 18, 2007

Q: What these 2 consecutive CXR tells you?

2007-05-17T13:36:00.000-06:00

Thursday May 17, 2007
FFP and platelet transfusion may be associated more with ALI/ARDS than pRBC transfusion

This is a well known fact that transfusion cause acute lung injury (ALI) / ARDS. but this is probably the first study which has formally evaluated the transfusion of specific blood products as a risk factor for ALI/ARDS in critically ill medical patients. Study is published in this month issue of chest 1.

Dr. Hasrat Khan and coll. from Mayo Clinic College of Medicine, Rochester, MN has looked into 841 consecutive critically ill patients and compared 298 patients who received blood product transfusions with those who did not. ALI/ARDS developed more commonly (25% vs 18%) in patients exposed to any transfusion.

Seventeen patients received massive RBC transfusions (ie, more than 10 units of blood transfused within 24 hours), of whom 13 also received fresh-frozen plasma (FFP) and 11 received platelet transfusions.

Among those patients receiving individual blood products, ALI/ARDS was more likely to develop in patients who received FFP transfusions (OR, 2.48) and platelet transfusions (OR, 3.89) than in those who received only RBC transfusions (OR, 1.39).

Study Concluded that transfusion is associated with an increased risk of the development of ALI/ARDS in critically ill medical patients. The risk is higher with transfusions of plasma-rich blood products, FFP, and platelets, than with RBCs.

Reference: click to get abstract
1. Fresh-Frozen Plasma and Platelet Transfusions Are Associated With Development of Acute Lung Injury in Critically Ill Medical Patients - Chest. 2007; 131:1308-1314

2007-05-16T12:37:00.000-06:00

Wednesday May 16, 2007
Right or biventricular ventricular assist device (RVAD or BiVAD)

Continuing our theme from yesterday on LVAD , Right Ventricular assist device (RVAD) provide support for failed right ventricle and connects it to pulmonary artery. Another extreme is to provide support to both ventricles simultaneously and its called BiVAD or Biventricular assist device.

Related: See Video Dr. Dow's pump from Dr. Cohen at Texas Heart Institute, Houston - also describing mechanism of presently used pulsatile and centrifugal (continuous) VADs.

2007-05-15T11:29:00.000-06:00

Tuesday May 15, 2007
What is Implantable left ventricular assist device (LVAD)

A ventricular assist device (VAD) is a mechanical pump that helps failed heart pump blood throughout the body. It was destined to used as a "bridge-to-transplant" but it is also a destined therapy for many patients who are not eligible for transplant. Actually, recently it has been reported that LVAD may reverse the heart failure by prolonged unloading of the myocardium causing myocardial recovery ! 1 There are many commercially type pumps available in market but basic idea is the same to help weak ventricle in pumping blood. There are 2 basic kinds available though - Pusatile and continuous (or debakey which is totally implanted inside the body). Parts consist of

1. A pump unit, implanted in the abdomen (very thin patients becomes ineligible)

2. An inflow tube (or conduit), attached to the bottom of the apex of left ventricle

3. An outflow tube, attached to the aorta Internal valves that allow for one-way blood flow through the system

4. Power leads, that pass from the internal device through the skin.

5. External controller and power base unit or battery pack that attaches to the power leads/cables.

The controller is programmed to maintain a specific pump spread. It displays the status of the system and sounds alarms if any. The controller and batteries can be worn in a belted waist pack or a holster under the arm. Or, it may be connected to a power base unit and plugged into a wall outlet.

References: click to get article / abstract

1. Left Ventricular Assist Device and Drug Therapy for the Reversal of Heart Failure - NEJM, Volume 355:1873-1884, November 2, 2006

2007-05-14T07:42:00.000-06:00

Monday May 14, 2007
Role of continuous renal replacement therapy (CRRT) in critical care setting still not clear

Acute Kidney Injury (AKI) in critically ill patients is sometimes associated with multi organ dysfunction syndrome (MODS). Patients who require dialysis have mortality rate over 50%. CRRT instead of intermittent hemodialysis (IHD) is being used in several institutions in this setting. The critical care physicians and nursing staff now often manage CRRT, rather than the nephrologists and dialysis nurses. However there is no data to show that CRRT is superior to IHD in critically ill patients probably because these patients are sicker and are difficult to study 2, 3.

Previous related pearl: Is SLEDD better than CVVHD in ICU patients ?

References: click to get article / abstract

1. Continuous renal replacement in critical illness - Contrib Nephrol. 2007;156:309-19
2. Survival by dialysis modality in critically ill patients with acute kidney injury - J Am Soc Nephrol. 2006 Nov;17(11):3132-8. Epub 2006 Oct 4.
3. Renal replacement therapy for acute kidney injury: let's follow the evidence - Int J Artif Organs. 2007 Feb;30(2):89-94

2007-05-13T08:44:00.001-06:00

Sunday May 13, 2007
Great Critical Care Video lectures - and they are free !!

David Crippen, MD, FCCM, Associate Professor at University of Pittsburgh Medical Center, Department of Critical Care Medicine has done a great service to the education of Critical Care Medicine. He has started free video lecture series and five videos have been loaded (and more are coming so bookmark it):

First: Introducion.

Second: Crippen: Sedation and Anxiolysis: ICU Case Studies, Part 1- Introduction to ICU stress delirium.

Third: Crippen: Sedation and Anxiolysis: ICU Case Studies, Part 2- Case studies of delirium, pain, anxiety and discomfort in the ICU.

Fourth: Crippen: Sedation and Anxiolysis: ICU Case Studies, Part 3- Severe, life threatening delirium using ethanol withdrawal as a model.

Fifth: Crippen: Sedation and Anxiolysis: ICU Case Studies, Part 4- Cerebral function monitoring using compressed spectral array (CSA) for therapeutically paralyzed patients.

You must have "Flash" loaded. (upload free if needed here)

Click at: http://ccm-l.org/CMEcrippen/videos.html

2007-05-12T16:50:00.000-06:00

Saturday May 12, 2007
Xifaxan (Rifaximin)

Rifaximin is in use in other countries since last 2 decades but has been approved by FDA in USA just couple of years ago. Rifaximin was invented initially in Italy for the treatment of travelers' diarrhea but quickly found its way for improvement in hepatic encephalopathy beside lactulose and neomycin 1, 2,5,6,7. Some new studies showed that it may be more effective than lactulose 3 or neomycin 4.Atleast one multi-center trial is underway 8, as well as other trials looking at Rifaximin's efficacy in Irritable Bowel Syndrome, Clostridium Difficile-Associated Diarrhea and Ulcerative Colitis 8.Rifaximin is an oral, semi-synthetic, nonsystemic antibiotic. The recommended dosage in hepatic encephalopathy is 1200 mg a day in divided doses.

References: click to get abstract/article

1. Rifaximin in the treatment of chronic hepatic encephalopathy - Curr Med Res Opin. 1995;13(5):274-81.

2. Rifaximin, a non-absorbable rifamycin, for the treatment of hepatic encephalopathy. A double-blind, randomised trial. - Curr Med Res Opin. 1997;13(10):593-601.

3. Comparison of rifaximin and lactitol in the treatment of acute hepatic encephalopathy: results of a randomized, double-blind, double-dummy, controlled clinical trial - J Hepatol. 2003 Jan;38(1):51-8

4. Neomycin should not be used to treat hepatic encephalopathy - BMJ 2001;323:233 ( 28 July )

5. Management of Hepatic Encephalopathy: Role of Rifaximin - Chemotherapy 2005;51 (Suppl. 1):90-95

6. Evaluation of the efficacy and safety of rifaximin in the treatment of hepatic encephalopathy: a double-blind, randomized, dose-finding multi-centre study. Eur J Gastroenterol Hepatol 2000; 12: 203-208

7. Rifaximin, a nonabsorbed oral antibiotic, in the treatment of hepatic encephalopathy: antimicrobial activity, efficacy and safety. Reviews in Gastroenterological Disorders, 5 (Supplement 1). S10-S18.

8. Rifaximin trials - clinicaltrials.gov

2007-05-11T16:58:00.000-06:00

Friday May 11, 2007
Hypokalemia and Hypertension !

Interesting article published this week in The New England Journal of Medicine: Sodium and Potassium in the Pathogenesis of Hypertension. Just to quote few lines from article:

"........Numerous studies show an adverse effect of a surfeit of sodium on arterial pressure. By contrast, potassium, the main intracellular cation, has usually been viewed as a minor factor in the pathogenesis of hypertension. However, abundant evidence indicates that a potassium deficit has a critical role in hypertension and its cardiovascular sequelae.......Population studies have shown an inverse relation of potassium intake to blood pressure, the prevalence of hypertension, or the risk of stroke.... After adjusting for potentially confounding variables, the INTERSALT (The International Study of Salt and Blood Pressure) researchers estimated that a decrease in potassium excretion by 50 mmol per day was associated with an increase in systolic pressure of 3.4 mm Hg and an increase in diastolic pressure of 1.9 mm Hg............ A high-potassium diet and increases in serum potassium, even within the physiologic range, cause endothelium-dependent vasodilatation by hyperpolarizing the endothelial cell through stimulation of the sodium pump and opening potassium channels....The central actions of changes in the concentrations of sodium and potassium in the cerebrospinal fluid and of an excess of sodium and a deficit of potassium in the body are probably mediated by changes in the activity of the neuronal sodium pump and the renin–angiotensin system in the brain. These changes alter sympathetic outflow, which then causes directional changes in blood pressure. Baroreceptor sensitivity is depressed by potassium depletion and restored by potassium supplementation.......In its 2002 advisory, the coordinating committee of the National High Blood Pressure Education Program identified both a reduction in dietary sodium and potassium supplementation as proven approaches for preventing and treating hypertension. The Institute of Medicine...also advises adults to consume at least 120 mmol of potassium per day (approximately 4.7 g of potassium per day, which is about twice the current U.S. average)......"

Reference: click to get abstract

Sodium and Potassium in the Pathogenesis of Hypertension - Volume 356:1966-1978 , May 10 2007

2007-05-10T10:58:00.000-06:00

Thursday May 10, 2007
What is Tandem Heart®
To support cardiac failure or to bridge the time till permanent solution found (cardiac surgery, heart transplant etc) various mechanical circulatory support systems have been used. Intraaortic balloon pump (IABP) is the most widely used measure but it is limited in its funtion due to support it provides and in its relatively shorter duration of use desired.

The Tandem Heart® Percutaneous Ventricular Assist Device (pVAD)™ system uses a transseptal cannula that allows direct unloading of the left heart at blood flow rates sufficient to sustain patients.

In TandemHeart a percutaneous catheter inserted at the right femoral vein, advanced upto right atrium, and under flouroscopy literally a hole is made in the interatrial septum (in the fossa ovalis). Next an arterial catheter inserted percutaneously into the right femoral artery (or two arterial catheters into both femoral arteries) and then advanced into the lower abdominal aorta. Catheters made connected to a centrifugal pump. Heparin is used continuously through the lubrication system of the device, adjusting the activated clotting time (maintained at 200 seconds).

The Tandem Heart has a low blood surface contact area, resulting in reduced potential for hemolysis and thromboemboli.

Data suggests it to be a promising technology and may become a regular feature in coronary care units. In references below, we are providing results from well done studies and bedside work.

References: click to get abstracts/articles

1. Reversal of Cardiogenic Shock by Percutaneous Left Atrial-to-Femoral Arterial Bypass Assistance - (Circulation. 2001;104:2917.)

2. Clinical Experience with the TandemHeart® Percutaneous Ventricular Assist Device - Tex Heart Inst J. 2006; 33(2): 111–115.

3. Temporary assist device for postcardiotomy cardiac failure - Ann Thorac Surg 2004;77:1431-1433

4. Left ventricular assist devices as permanent heart failure therapy: the price of progress.- Ann Surg. 2003 Oct;238(4):577-83; discussion 583-5

5. Percutaneous left ventricular assist device: "TandemHeart" for high-risk coronary intervention. - Catheter Cardiovasc Interv. 2005 Jul;65(3):346-52.

2007-05-09T07:35:00.001-06:00

Wednesday May 09, 2007

Q; Patients with which poisoning present with garlic odor?

A: Organophosphate poisoning.

2007-05-08T22:29:00.000-06:00

Tuesday May 08, 2007
PPI (Proton pump inhibitor) drip !

One notable study recently published in The New England Journal of Medicine regarding use of preemptive Omeprazole (PPI) infusion - 80 mg IV bolus followed by an 8 mg per hour drip - before Endoscopy in Patients with Gastrointestinal Bleeding. The basic concept is a neutral gastric PH is critical for the stability of clots over bleeding arteries.

638 patients were enrolled and randomly assigned to omeprazole or placebo (319 in each group).

Patients with hypotensive shock had been first stabilized. Patients requiring urgent endoscopy or surgery were excluded. Long term aspirin users were excluded. For nonsteroidal antiinflammatory drugs users, the drugs were discontinued. Patients who had bleeding from coumadin were given vitamin K or FFP. - See full article for inclusion or exclusion criteria.

Results:
The need for endoscopic treatment was lower in the omeprazole group than in the placebo group ( 19.1% vs. 28.4%).
The hospital stay was less than 3 days in 60.5% of patients in the omeprazole group, as compared with 49.2% in the placebo group.
On endoscopy, fewer patients in the omeprazole group had actively bleeding ulcers (12 of 187, vs. 28 of 190 in the placebo group) and
more omeprazole-treated patients had ulcers with clean bases (120 vs. 90).

But there were no significant differences in the mean amount of blood transfused, the number of patients who had recurrent bleeding, who underwent emergency surgery or who died within 30 days.

Authors concluded that Infusion of high-dose omeprazole before endoscopy accelerated the resolution of signs of bleeding in ulcers and reduced the need for endoscopic therapy.

Reference: click to get article/abstract

1. Omeprazole before Endoscopy in Patients with Gastrointestinal Bleeding -, NEJM, April 19, 2007, Volume 356:1631-1640

2007-05-07T13:45:00.000-06:00

Monday May 07, 2007

Revisting Intra-Abdominal Hypertension (IAH)

Intra-Abdominal Hypertension (IAH) and Abdominal Compartment Syndrome (ACS) are encountered in critical care setting, which requires prompt identification and management.

DEFINITIONS

1. Intraabdominal pressure (IAP): The steady-state pressure concealed within the abdominal cavity.

2. Abdominal perfusion pressure (APP):

APP = MAP - IAP
* Mean arterial pressure (MAP)

3. Intra-abdominal Hypertension (IAH): IAH is defined by a sustained or repeated pathologic elevation of IAP >12 mmHg. Normal IAP is approximately 5-7 mmHg in critically ill adults.

4. Abdominal Compartment Syndrome (ACS): ACS defined as a sustained IAP > 20 mmHg (with or withou an APP less than 60 mmHg) that is associated with new organ dysfunction / failure.

HOW TO MEASURE

IAP should be expressed in mmHg (1 mmHg = 1.36 cmH2O) and measured at end-expiration in the complete supine position after ensuring that abdominal muscle contractions are absent and with the transducer zeroed at the level of the mid-axillary line. The reference standard for intermittent IAP measurement is via the bladder with a maximal instillation volume of 25 mL of sterile saline. Normal IAP is approximately 5-7 mmHg in critically ill adults.

GRADES of IAH:

Grade I , 12-15 mmHg

Grade II, 16-20 mmHg

Grade III, 21- 25 mm Hg

Grade IV, more than 25 mm Hg

Related web site: The World Society of the Abdominal Compartment Syndrome (WSACS)

See following diagram from commercially available product - AbViser® AutoValve™ - click on pic to get bigger image

2007-05-06T08:58:00.000-06:00

Sunday May 06, 2007

Q; How much intavenous albumin should be given to patient while removing ascitic fluid via paracentesis?

A; Per 2004 guidelines published in Hepatology 2004 Mar;39(3):841-56, for management of adult patients with ascites due to cirrhosis by Practice Guidelines Committee, American Association for the Study of Liver Diseases (AASLD),

"Post-paracentesis albumin infusion may not be necessary for a single paracentesis of less than 4 to 5 L. For large-volume paracenteses, an albumin infusion of 8 to 10 g per liter of fluid removed can be considered". (Grade II-2 evidence - Cohort or case-control analytic studies).

Read full guidelines here

2007-05-05T13:37:00.000-06:00

Saturday May 05, 2007
Revisiting Pulmonary Artery Diastolic-Pulmonary Wedge Pressure Gradient

Floatation of pulmonary artery catheter (PAC) in ICUs is towards downward trend. Lets revisit one important but forgotten value obtained via PAC.

PADP - PAOP
(Pulmonary Artery Diastolic-Pulmonary Wedge Pressure) Gradient.

Most of the literature in regards to this value is 15-30 years old but proven to be very easy to calculate but very vital to follow 1, 3. Once this gradient starts to exceeds by 6 mm Hg or more, the patient has shown to have a much poorer prognosis particularly in septic patients. Probable explanation is pulmonary venous vasoconstriction induced by endotoxemia in sepsis or postcapillary lekocyte aggregation in development of ARDS 2, 4.

One study suggests that although an initial PAD-PWP gradient in patients with sepsis is associated with a high mortality, a much more sensitive indicator is to follow the trend. There was a 91% mortality in patients with persisting or increasing gradients 2.

References: click to get abstract/artice

1. Pulmonary hypertension in sepsis: Measurement by the pulmonary arterial Diastolic-pulmonary wedge pressure gradient and the influence of passive and active factors. Chest 1978; 73:583-91

2. Significance of the pulmonary artery diastolic-pulmonary wedge pressure gradient in sepsis. Crit Care Med 1982; 10:658-61

3. Pulmonary artery diastolic and wedge pressure relationships in critically and injured patients. Arch Surg 1988; 123:933-6

4. Increased Pulmonary Venous Resistance Contributes to Increased Pulmonary Artery Diastolic-Pulmonary Wedge Pressure Gradient in Acute Respiratory Distress Syndrome - Anesthesiology: Volume 102(3) March 2005 pp 574-580

2007-05-04T22:05:00.000-06:00

Friday May 04, 2007

Scenario: You have been called to see a consult for a patient with mental status change and anasarca. On arrival you noticed a young man lying supine in bed with facial edema, upper extremity edema, lethargy, papilledema and neck veins visible. You suspect Superior Vena Caval Snydrome. What is the first thing you will do, may be even before start talking to patient ?

Answer: Have patient sit upright.

Patients with apparent clinical SVC syndrome gain significant symptomatic improvement from elevation of the head of the bed due to release of fluid pressure with gravity. It is a very benign maneuver but very significant for a patient as it provides dramatic relief of symptoms.

This week The New England Journal of Medicine has a nice writeup on Superior Vena Cava Syndrome with Malignant Causes - Volume 356:1862-1869, Number 18, May 3, 2007

2007-05-03T21:07:00.000-06:00

Thursday May 03, 2007
Linezolid and side-effects

Thrombocytopenia could be multifactorial in ICU. One of the relatively new cause is Linezolid (Zyvox). But thrombocytopenia with Zyvox usually doesn't occur upto 10 days after the initiation of treatment and reported in upto 32% of patients. Relatively overall its mild, reversible and due to myelosuppression. there is no evidence for anti-platelet or interference with platelet function. Patients with low pre-treatment platelet values have increase risk of thrombocytopenia 6.

Other side-effects include leukopenia, transient elevations of liver transaminases 4 and mild to moderate anemia 5. Cases have been reported of LINEZOLID-INDUCED LACTIC ACIDOSIS 7, 8.

References: click to get abstract/article

1. Hematologic Effects of Linezolid: Summary of Clinical Experience - Antimicrobial Agents and Chemotherapy, August 2002, p. 2723-2726, Vol. 46, No. 8
2. Linezolid and reversible myelosuppression. - JAMA 285:1291
3. Safety, efficacy and pharmacokinetics of linezolid for treatment of resistant Gram-positive infections in cancer patients with neutropenia - Annals of Oncology 14:795-801, 2003
4. Zyvox (linezolid) package insert. Pharmacia & Upjohn
5. Linezolid-Induced Anemia and Thrombocytopenia - Pharmacotherapy 22(1):109-112, 2002
6. Linezolid: low pre-treatment platelet values could increase the risk of thrombocytopenia - Journal of Antimicrobial Chemotherapy 2005 56(2):440-441;
7. LINEZOLID-INDUCED LACTIC ACIDOSIS - Linezolid-induced lactic acidosis. N Eng J Med, 2003; 348 :86 -7.
8. Does Linezolid Cause Lactic Acidosis by Inhibiting Mitochondrial Protein Synthesis? Clinical Infectious Disease2005; 40 :e113 -6

2007-05-02T09:02:00.000-06:00

Wednesday May 02, 2007
Esophageal intubation

We are reproducing a part of a case report of esophageal intubation for learning purpose. (You can read full case by clicking the link below).

"....A decision was made to insert a prophylactic left thoracostomy tube and intubate the patient prior to going to the OR. Rapid sequence intubation (RSI) was initiated using atropine and fentanyl followed by midazolam and succinylcholine. The ETT was perceived by the operator to have been passed into the trachea by direct vision. Auscultation of both axilla noted "good air entry," and condensation of water vapour in the tube was also noted. Neither an end tidal CO2 monitor nor an esophageal detector device were used. An arterial blood gas sample drawn during the pre-oxygenation phase of the RSI showed that the Po2 was 286 mm Hg with 99.6% oxygen saturation. Follow-up oxygen saturation was not documented. Blood was suctioned from the ETT shortly after intubation. A repeat chest/abdominal x-ray was taken, and the patient was transferred directly to the OR. The x-ray film was not viewed by the attending physician prior to sending the patient to the OR, due to the immediacy of the transfer. Upon arrival at the OR, the patient was found to have pulseless electrical activity, with a heart rate of 40 beats/min. A grossly distended abdomen was noted. Surgical emphysema was present across the abdomen, thorax and neck. Immediate assessment of the airway revealed an esophageal intubation. Airway edema and anatomic distortion secondary to surgical emphysema prevented endotracheal intubation, and a tracheostomy was performed. The patient's rhythm rapidly deteriorated to asystole and, despite all efforts, resuscitation was unsuccessful. The official x-ray reading the following day erroneously reported the ETT to be in the right main stem bronchus."

Lessons to be learned:

1. Despite your belief that you watched ETT pass through the vocal cord, there are chances that it may have went into esophageal tract.

2. Bilateral breath sounds and condensation of water vapour in ETT are not a reliable indicator of tracheal intubation.

2. All possible means available to confirm ETT in trachea should be used including CXR and end-tidal CO2 monitor. End-tidal CO2 monitor is pretty reliable but may give false positive results 1 (or false negative results in code situation). Bronchoscopy should be performed if doubt persists.

4. Followup ABG should be done to see PO2 and other values.

5. Followup CXR should be done as soon as possible and should be read by the operator despite patient is moved from the area !

6. Esophageal intubation is an emergency and need to be recognised and corrected promptly.

7. Don't wait for official CXR report !!

You can read the full case report with discussion here (reference: Canadian Association of Emergency Physicians, January 2002 Vol 4, No 1)

Reference: click to get abstract

1. Case report: a normal capnogram despite esophageal intubation - Canadian Journal of Anesthesia 48:1025-1028 (2001)

2007-05-01T08:06:00.000-06:00

Tuesday May 01, 2007

Q; Is equal breath sounds a reliable indicator of proper placement of endotracheal tube ?

A: No

Equal breath sounds can be heard in up to 60% of right main stem intubations 1. A chest radiograph should always be done to confirm proper placement of ETT in ICUs. An end-tidal CO2 monitoring just tells that you are in right tract. Fiberoptic bronchoscopy is a more reliable means of confirming ETT position. Recently, hand held ultrasound is suggested as a quick mean to confirm proper placement of ETT 3. One reliable formula 2 which also found to have good clinical correlation, is

ETT length (incisors to midpoint of trachea, cm) = patient's height (cm)/10+5

Like, if patient's height is 170 cm, ETT should be taped at

170/10 + 5 = 22 cm

Reference: click to get abstract

1. Assessment of routine chest roentgenograms and the physical examination to confirm endotracheal tube position.- Chest1989;96:1043-1045.
2. Anaesthesia Intensive Care 1992; 20:156
3. Where’s the Tube? Evaluation of Hand-held Ultrasound in Confirming Endotracheal Tube Placement - Prehosp Disast Med 2004;19(4):366–369.