Thursday June 17, 2010
Therapeutic ranges anti-Xa level for adequate anticoagulation

This is important to note that therapeutic ranges anti-Xa level are different with different anticoagulation.

Heparin: 0.3-0.7 units/mL

LMWH:

• 0.4-1.1 units/mL for SQ q 12 hr dosing.
• For once daily LMWH dosing, the therapeutic range is approximately 1-2 units/mL.

Prophylaxis of DVT: There is no defined target range for prophylaxis of DVT. When anti-Xa levels are measured, the values are lower 0.45.

Wednesday June 16, 2010
Pulmonary Artery Occlusion Pressure and PEEP

There are 3 ways to correct/manage pulmonary artery occlusion pressure or pulmonary capillary wedge pressure (PCWP) in patients with PEEP (positive end-expiratory pressure) over 10.

1. Follow the trend of PCWP co-relating with other clinical data and interventions.

2. Corrected PCWP = Measured PCWP - .5 x (PEEP/1.36)

e.g. If measured PCWP is 20 and applied PEEP is 16:

Corrected PCWP = 20 - .5 (16/1.36) = 14.12

3. Corrected PCWP = measured PCWP - esophageal pressure.Temporary discontinuation of PEEP to measure PCWP is not safe and should be avoided.

References: click to get abstract/article

1. Influence of positive end-expiratory pressure on left ventricular performance - NEJM, Feb. 1981, Volume 304:387-392

2. Monitoring Pulmonary Artery Pressure - Crit Care Nurse 2004 Jun;24(3):67-70

3. Swan-Ganz Catheterization - online emedicine.com

Tuesday June 15, 2010
Pulmonary Embolism - needs faster anticoagulation

Background: Acute pulmonary embolism (PE) may be rapidly fatal if not diagnosed and treated. IV heparin reduces mortality and recurrence of PE, but the relationship between survival and timing of anticoagulation has not been extensively studied.

Methods: We studied 400 consecutive patients in the ED diagnosed with acute PE by CT scan angiography and treated in the hospital with IV unfractionated heparin from 2002 to 2005. Patients received heparin either in the ED or after admission. Time from ED arrival to therapeutic activated partial thromboplastin time (aPTT) was calculated. Outcomes included in-hospital and 30-day mortality, hospital and ICU lengths of stay, hemorrhagic events on heparin, and recurrent venous thromboembolism within 90 days.

Results:

• In-hospital and 30-day mortality rates were 3.0% and 7.7%, respectively.
• Patients who received heparin in the ED had lower in-hospital (1.4% vs 6.7%; P = .009) and 30-day (4.4% vs 15.3%; P less than .001) mortality rates as compared with patients given heparin after admission.
• Patients who achieved a therapeutic aPTT within 24 h had lower in-hospital (1.5% vs 5.6%; P = .093) and 30-day (5.6% vs 14.8%; P = .037) mortality rates as compared with patients who achieved a therapeutic aPTT after 24 h.
• In multiple logistic regression models, receiving heparin in the ED remained predictive of reduced mortality, and ICU admission remained predictive of increased mortality.
  

Conclusions: We report an association between early anticoagulation and reduced mortality for patients with acute PE. We advocate further study with regard to comorbidities to assess the usefulness of modifications to hospital protocols.

Early Anticoagulation Is Associated With Reduced Mortality for Acute Pulmonary Embolism - CHEST June 2010 vol. 137 no. 6 1382-1390

Monday June 14, 2010
Holiday Heart Syndome

Holiday Heart Syndome was originally defined as "arrhythmias of the heart, sometimes apparent after a vacation or weekend away from work, following excessive alcohol consumption; usually transient". Same has been reported with recreational use of marijuana. The most common rhythm disorder is atrial fibrillation, which usually converts to normal sinus rhythm within 24 hours. It occurs in patients without structural heart disease and its clinical course is usually benign. Even modest alcohol intake may trigger paroxysmal atrial fibrillation.

Most patients with no evidence of structural heart disease can be discharged without further treatment once arrhythmia has stabilized with advise against the excessive use of alcohol. Patients with sustained tachyarrhythmia require treatment if the ventricular rate is excessive. Patients with structural heart disease needs further workup.

Sunday June 13, 2010
Effect of statin therapy on reperfusion arrhythmia - Interesting study


Background In animal models, pretreatment with statin can prevent reperfusion arrhythmia. In the observational study, we investigated whether pretreatment with statin may prevent reperfusion arrhythmia in patients who underwent primary coronary intervention for acute myocardial infarction (AMI).

Method and results A total of 226 consecutive patients who underwent successful primary angioplasty for a first AMI were studied. Reperfusion arrhythmias were defined as all arrhythmias that occurred within 2 h after successful primary angioplasty. The reperfusion arrhythmia was found in 130 of 226 patients. There were no significant differences in clinical characteristics between the patients with and without statin pretreatment.

• The 41 patients receiving statin treatment before admission had lower incidence of the reperfusion arrhythmia than those without it (19.5% and 65.9%)
• Multivariable logistic regression analysis revealed that absence of statin pre-treatment was a significant predictor of the reperfusion arrhythmia along with absence of pre-infarction angina and inferior AMI
  

Conclusion Pre-treatment with statin could reduce the reperfusion arrhythmias after acute myocardial infarction in human.


Effect of statin therapy on reperfusion arrhythmia in patients who underwent successful primary angioplasty - Clinical Research in Cardiology, Volume 97, Number 3 / March, 2008, 147-151

Saturday June 12, 2010
Oxygen toxicity!

Oxygen is essential to life but can turn into a poison too. Most molecular oxygen used by mitochondria is metabolically reduced completely to water during normal cellular respiration, but a certain quantity of partially reduced, reactive oxygen metabolites is also generated. Chief among these toxic metabolites are superoxide anion, hydrogen peroxide and reactive hydroxyl radicals. Of these, the last are believed to be the most toxic.

According to literature available - On 100% oxygen breathing

• After 6 hours - decreased tracheal mucus velocity is detectable
• After 12 hours - signs of tracheobronchitis appear
• Between 24 - 30 hours - abnormalities in gas exchange are detectable
• At 72 - 96 hours - edema can be documented
• After 96 hours - fibrosis may began
  
  

Jackson RM. Oxygen therapy and toxicity. In: Ayres SM, Grenvik A, Holbrook PR, Shoemaker WC, eds. Textbook of Critical Care. 3rd ed. 784-789

Friday June 11, 2010
Dopamine or NE?

Background: Both dopamine and norepinephrine are recommended as first-line vasopressor agents in the treatment of shock. There is a continuing controversy about whether one agent is superior to the other.

Methods In this multicenter, randomized trial, we assigned patients with shock to receive either dopamine or norepinephrine as first-line vasopressor therapy to restore and maintain blood pressure. When blood pressure could not be maintained with a dose of 20 µg per kilogram of body weight per minute for dopamine or a dose of 0.19 µg per kilogram per minute for norepinephrine, open-label norepinephrine, epinephrine, or vasopressin could be added.

The primary outcome: rate of death at 28 days after randomization;
Secondary end points: number of days without need for organ support and the occurrence of adverse events.

Results The trial included 1679 patients, of whom 858 were assigned to dopamine and 821 to norepinephrine. The baseline characteristics of the groups were similar.

• There was no significant between-group difference in the rate of death at 28 days (52.5% in the dopamine group and 48.5% in the norepinephrine group; P=0.10).
• There were more arrhythmic events among the patients treated with dopamine than among those treated with norepinephrine (207 events [24.1%] vs. 102 events [12.4%], P less than 0.001).
• A subgroup analysis showed that dopamine, as compared with norepinephrine, was associated with an increased rate of death at 28 days among the 280 patients with cardiogenic shock but not among the 1044 patients with septic shock or the 263 with hypovolemic shock
  

Conclusions Although there was no significant difference in the rate of death between patients with shock who were treated with dopamine as the first-line vasopressor agent and those who were treated with norepinephrine, the use of dopamine was associated with a greater number of adverse events.


Comparison of Dopamine and Norepinephrine in the Treatment of Shock - Volume 362:779-789, Number 9, March 4 2010

Thursday June 10, 2010
A note on Amiodarone vasodilatory property

One often less know property of Amiodarone, a class III antiarrhythmic agent, is its potent coronary as well as veno vasodilatory property. Amiodarone acts as a venodilator through the cyclooxygenase pathway, activation of nitric oxide synthase, blockade of -adrenergic mechanismsn and cyclooxygenase-dependent relaxing endothelial factors. Amiodarone hasalso shown in laboratory the calcium channel blocking effects. Due to its multiple effects amiodarone therapy has shown beneficial effect in heart failure.

On side note - Hypotension from IV amiodarone (particularly bolus) is also contributed due to its solubilized vehicle called polysorbate 80 which may have histamine releasing effect.

Wednesday June 9, 2010
Collection of Lactic acid and Tourniquet - bedside tip

Monitoring of Lactic acid level is helpful in both identifying potentially serious ill patients as well as identifying in the ICU patients with high morbidity and mortality. Elevated lactate levels may be related to sampling error as a result of recent patient activity, tourniquet use, or delayed sample processing.

When a patient arrives to an ED or ICU and that patient is hypotensive (BP less than or equal to 90 systolic), the nursing staff often starts an IV and if possible draws the patient's initial blood tests off that first IV site. This initial work up by the nursing staff takes 15 -20 minutes before a physician may see the patient.

It is recommended to draw lactic acid without a tourniquet or immediately after applying the tourniquet. If the tourniquet is applied for an extended time, remove the tourniquet and let the blood circulate two minutes prior to retrying the draw. Collect specimen in gray top tube. Invert specimen container gently to mix. Transport on ice. Specimen must be delivered to Chemical Pathology Laboratory within 15 minutes of collection.

Tuesday June 8, 2010
Pharmacy


Q: Tell few off-label (or experimental) uses of Metformin?


Answer:

• Prediabetes
• Polycystic ovary syndrome (PCOS)
• Non-alcoholic fatty liver disease (NAFLD)
• Premature puberty
• Gestational diabetes (?)
• Prophylactically against pancreatic cancer

Monday June 7, 2010

Picture Diagnosis

Answer: Septic pulmonary embolism (SPE)

Note following features

• Round or wedge-shaped multiple peripheral opacities
• Usually measure approximately 1-3 cm in diameter,
• Frequently cavitated
• Well-defined or poorly defined margins

Findings on CXR tend to be nonspecific, CT may yield helpful clues that may suggest the diagnosis of SPE. Parenchymal lesions related to SPE are usually multiple and nodular with a peripheral distribution and a tendency for cavitation. “Feeding vessel” sign (a vessel leading to a peripheral lung lesion) is described as a characteristic feature of SPE, but is not always present.

Sunday June 6, 2010
Arizona Immigration Law and Medical Practice -

Published at www.nejm.org June 2, 2010

To the Editor: The new Arizona state immigration bill (SB-1070) signed into law on April 23 will seriously obstruct, if not undermine, the practice of medicine in the state of Arizona...........

Read full letter here

Saturday June 5, 2010

Q: Role of Ethanol, Fomepizole and Hemodialysis are well known in Methanol toxicity. Describe the role of bicarbonate in Methanol toxicity meanwhile above 3 treatments/antidote get arranged?


Answer: It is true that Ethanol, Fomepizole and Hemodialysis are mainstay of treatment in Methanol toxicity but often ignored is the role of bicarbonate in Methanol toxicity.

Actually Methanol itself has a relatively low toxicity. The adverse effects are from the accumulation of formic acid, a metabolite of methanol metabolism. Upon ingestion, methanol is quickly absorbed in the gastrointestinal tract and metabolized in the liver. In the first step of degradation, methanol is transformed to formaldehyde via the enzyme alcohol dehydrogenase (ADH). The next step is the transformation of formaldehyde to formic acid via the enzyme aldehyde dehydrogenase. Bicarbonate may help to decrease the amount of active formic acid. In addition, Bicarbonate potentially may reverse visual deficits.

Friday June 4, 2010
Use of noninvasive positive pressure ventilation during pregnancy

Noninvasive positive pressure ventilation (NIPPV) is increasingly used to treat acute respiratory failure in nonpregnant patients, but literature of its use during pregnancy is almost none. Acute respiratory failure (ARF) remains a leading cause of ICU admission in obstetric patients. We found a report of case series of successful use of NIPPV in pregnancy.

Report is the outcome of treatment with NIPPV of four sickle cell disease pregnant patients with ARF caused by acute chest syndrome. Median APACHE II score for the four cases was 27.


Results:

• Intubation was avoided in all cases.
• None had aspiration.
• Mean duration of NIPPV was 40 h
• ICU discharge after a mean of 4 days
  

Conclusion: In closely monitored pregnant patients with Acute Respiratory Failure, NIPPV seems to have the potential to shorten ICU and hospital stay. A well-conducted randomized controlled clinical trial is required to confirm this finding


Use of noninvasive positive pressure ventilation during pregnancy: Case series - Ann Thorac Med. 2007 Jan–Mar; 2(1): 23–25

Thursday June 3, 2010


Q: How Desmopressin (DDAVP) helps in coagulation?


Answer: Desmopressin (DDAVP) helps in coagulation via 2 mechanism

1. Desmopressin stimulates release of factor VIII and von Willebrand factor (vWF) from endothelial cells due to stimulation of the V1a receptor.

2. Desmopressin is shown to be efficacious even in bleeding disorders not involving a deficiency or dysfunction of factor VIII or vWF, including congenital and acquired defects of platelet function as those associated with chronic kidney and liver diseases.



Reference: Click to get abstract
How do you treat bleeding disorders with desmopressin? - Postgrad Med J 2007;83:159-163

Wednesday June 2, 2010

Scenario: 52 year old male after emergent exploratory laparotomy is admitted to ICU. Patient has Lactated Ringer's solution going at 125 cc/hr. 2 units of pRBC were ordered. Why it is a bad idea to mix Lactated Ringer's solution and pRBC through same IV line?


Answer: Lactated Ringer's solution contains calcium which may bind to the citrate (use as anticoagulant) in blood products. This may promotes clot formation.

Tuesday June 1, 2010
Stenting versus Endarterectomy for Treatment of Carotid-Artery Stenosis

Background: Carotid-artery stenting and carotid endarterectomy are both options for treating carotid-artery stenosis, an important cause of stroke.

Methods : We randomly assigned patients with symptomatic or asymptomatic carotid stenosis to undergo carotid-artery stenting or carotid endarterectomy.
The primary composite end point was stroke, myocardial infarction, or death from any cause during the periprocedural period or any ipsilateral stroke within 4 years after randomization.

Results: For 2502 patients over a median follow-up period of 2.5 years,

• There was no significant difference in the estimated 4-year rates of the primary end point between the stenting group and the endarterectomy group
• There was no differential treatment effect with regard to the primary end point according to symptomatic status
• The 4-year rate of stroke or death was 6.4% with stenting and 4.7% with endarterectomy. The rates among symptomatic patients were 8.0% and 6.4%, and the rates among asymptomatic patients were 4.5% and 2.7% , respectively.
• Periprocedural rates of individual components of the end points differed between the stenting group and the endarterectomy group: for death (0.7% vs. 0.3%, P=0.18), for stroke (4.1% vs. 2.3%, P=0.01), and for myocardial infarction (1.1% vs. 2.3%, P=0.03). After this period, the incidences of ipsilateral stroke with stenting and with endarterectomy were similarly low (2.0% and 2.4%, respectively; P=0.85).

Conclusions: Among patients with symptomatic or asymptomatic carotid stenosis, the risk of the composite primary outcome of stroke, myocardial infarction, or death did not differ significantly in the group undergoing carotid-artery stenting and the group undergoing carotid endarterectomy. During the periprocedural period, there was a higher risk of stroke with stenting and a higher risk of myocardial infarction with endarterectomy.


Stenting versus Endarterectomy for Treatment of Carotid-Artery Stenosis - Published at www.nejm.org May 26, 2010