August 2009 icuroom.net archive

2009-08-31T13:24:00.000-07:00

Monday August 31, 2009
Hypertension management in perioperative period

Patients undergoing surgical procedures especially cardiac surgery can experience hypertensive urgencies (ie. severe blood pressure elevations without end organ dysfunction) or hypertensive emergencies (i.e. severe blood pressure elevations BP >180/110 mmHg with impending or progressive end organ damage), before, during, or after the procedure.

There are several continuous infusion options to control the hypertensive crisis:

Esmolol (ultra-short action cardioselective b blocker)

Preferred use: Acute myocardial ischemia, ideal choice when CO, HR, and BP are increased

Dose: LD 500-1000 microgram/kg over 1 minute; Infusion starting at 50 microgram/kg/min, titrating up to max 300 microgram/kg/min as needed to maintain BP

Rapid onset of 60 seconds, duration of action 10-20 minutes

Comment: Caution should be used in patient with COPD

Nicardipine (short-acting dihydropyridine CCB)

Preferred use: Acute myocardial ischemia, acute renal failure, acute ischemic stroke/intracerebral bleed, eclampsia/preeclampsia, hypertensive encephalopathy, sympathetic crisis/cocaine overdose

Dose: 5 mg/hr increasing by 2.5mg/hr every 5 minutes to maximum 15mg/hr until BP achieved. It has been seen that doses have been titrated up to 30-45 mg/hr.

Comment: Increases SV and coronary blood flow

Labetalol (a1 and non selective b1 blocker)

Preferred use: acute aortic dissection, acute myocardial ischemia, acute ischemic stroke/intracerebral bleed, eclampsia/preeclampsia hypertensive encephalopathy

Dose: May be given as bolus doses or continuous infusion, Bolus: LD 20mg IV, with incremental dose of 20-80mg every 10 minutes until BP achieved, Continuous IV: LD 20mg IV, infusion 1-2 mg/min titrated up until BP achieved, Max dose 300mg over 24 hours

Onset of action 2-5 minutes, duration of action 2-4 hours

Comment: Reduces SVR without reducing total peripheral blood flow. Caution should be taken in patients with HF. Avoid in patients with severe sinus bradycardia, heart block greater than 1st degree, and asthma.

Nitroglycerin (direct vasodilator or peripheral capacitance and resistance vessels)

Dose: 5 microgram/min every 5 minutes to 20 microgram/min. If not response at 20 microgram/min then increase by 10 microgram/min to max dose of 200 microgram/min, Onset of action 2-5 minutes, duration 10-20 minutes

Comments: Reduces BP by reducing preload and CO. Should not be used in patients with cerebral compromised or renal insufficiency

Sodium nitroprusside (arterial and venous vasodilator)

Preferred use: hypertensive emergency without cerebral compromise or renal/hepatic insufficiency

Dose: 0.5 microgram/kg/min titrated as tolerated, max 2 microgram/kg/min Onset of action is seconds, duration of action 1-2 minutes

Disadvantages: not recommended for patients who have decreased cerebral blood flow, accumulation of cyanide and thiocyanate

Comment: Duration of use should be limited to 72 hours due to the potential for toxicity

Reference:

Varon J. Vascular Health and Risk Management. 2008;4(3):615.
Varon J. Drugs. 2008;68(3):283

2009-08-30T07:37:00.000-07:00

Sunday August 30, 2009
"Permissive Undernutrition" ! / CRRT

Interesting lecture from Paul Marik, MD, FCCM, FCCP.
Click on link below, (Lecture length: 12 minutes 15 Seconds)

Nutrition in the Critically Ill-How much is enough? "Permissive Undernutrition"

Editors' note: Above lecture is located at a very informative site on CRRT (continuous renal replacement therapy)

CRRTonline.com

You may have to register (free)

This site is a full portal of information on CRRT including

Protocols
Case Management
Published Literature
System Based Approaches to CRRT
Utilizing CRRT/Machine Set-up
Fluid Management
Drug Management
Templates/Flow Sheets
Calculators
Existing Products/Links
Solution/Product Comparisons

icuroom.net has no financial relationship with any instiution or industry. Information provided here is solely for educational purpose.

2009-08-29T08:02:00.000-07:00

Saturday August 29, 2009
Supraclavicular Subclavian Vein Catheterization: The Forgotten Central Line?

Advantages of the supraclavicular approach over the infraclavicular technique include:

a well-defined insertion landmark (the clavisternomastoid angle);
a shorter distance from skin to vein;
a larger target area;
a straighter path to the superior vena cava; less proximity to the lung; and
fewer complications of pleural or arterial puncture.
The supraclavicular approach less often necessitates interruption of CPR or tube thoracostomy than the infraclavicular method.

(See reference article below)

Reference: click to get article

Supraclavicular Subclavian Vein Catheterization: The Forgotten Central Line - West J Emerg Med. 2009 May; 10(2): 110–114

2009-08-28T18:11:00.000-07:00

Friday August 28, 2009 (pediatric pearl)
Fetal haemoglobin

Fetal haemoglobin (which is present in fetal life and up to 3 months following birth) is not able to deliver oxygen to the tissues as efficiently as normal haemoglobin because the oxy-haemoglobin dissociation curve is shifted to the left causing oxygen to be released less readily. Neonates have a higher haemoglobin concentration (17 g/dl) and blood volume and this together with the increased cardiac output compensates for the decreased release of oxygen from haemoglobin in the tissues. Replacement of fetal haemoglobin with adult haemoglobin begins at 2-3 months of age and this period is known as physiological anaemia as haemoglobin concentrations may fall to 11 g/dl. Anaemia sufficient to jeopardise oxygen carrying capacity of the blood is possible if the haemoglobin concentration is less than 13 g/dl in the newborn and less than 10 g/dl in the infant under 6 months of age.

2009-08-27T09:04:00.000-07:00

Thursday August 27, 2009

Fecal loading in the cecum
What is your diagnosis?

Answer: Acute Appendicitis

Image of fecal loading in the cecum presented a sensitivityof 97% for acute appendicitis. The frequency of this sign is higher than the frequency of other signs included as part of the clinical, laboratory and even imaging workups for patients with acute appendicitis.

Reference:

Radiographic image of fecal loading in the cecum as a diagnostic sign of acute appendicitis - Radiol Bras vol.40 no.4 São Paulo July/Aug. 2007

2009-08-26T06:09:00.000-07:00

Wednesday August 26, 2009
Contamination of Portable Radiograph Equipment With Resistant Bacteria in the ICU

Background: Approximately 15% of nosocomial infections in the ICU result from spread of bacteria on caregivers' hands. The routine chest radiograph provides an unexamined opportunity for bacterial spread: close contact with each patient and sequential examination of ICU patients. This study examined infection control procedures performed during routine chest radiographs, assessed whether resistant bacteria were transferred to the radiograph machine, and determined whether improved infection control practices by radiograph technicians could reduce bacterial transfer.

Methods: Radiograph technicians were observed performing chest radiographs on all ICU patients. Culture specimens were taken from the radiograph machine. An educational intervention directed at technicians was instituted, and its effect on infection control and machine contamination was measured.

Results: Surveillance of 173, 113, and 120 chest radiographs during observation, intervention, and follow-up periods was performed.

Adequate infection control was practiced during the performance of 2 of 173 observation period radiographs (1%), 48 of 113 intervention period radiographs (42%), and 12 of 120 follow-up period radiographs (10%) [follow-up vs intervention and observation periods].
Radiograph machine surface culture samples yielded resistant Gram-negative bacteria on 12 of 30 occasions (39%), 0 of 29 occasions, and 7 of 14 occasions (50%), respectively, for the observation, intervention, and follow-up periods.

Conclusion: Multiresistant bacteria are frequently transferred from patients to the radiograph machine in the presence of poor infection control practices, and may be a source of cross-infection/colonization. Improved infection control practices decrease the occurrence of resistant organisms on the radiograph equipment. Radiograph technicians should be included in efforts to improve infection control measures.

Reference:

Contamination of Portable Radiograph Equipment With Resistant Bacteria in the ICU - CHEST August 2009 vol. 136 no. 2 426-432

2009-08-25T17:02:00.000-07:00

Tuesday August 25, 2009
Adenosine for wide-complex tachycardia: Efficacy and safety

Objectives: To determine whether adenosine is useful and safe as a diagnostic and therapeutic agent for patients with undifferentiated wide QRS complex tachycardia. The etiology of sustained monomorphic wide QRS complex tachycardia is often uncertain acutely.

Design: A retrospective observational study with emergency visits at nine urban hospitals. Consecutive patients treated with adenosine for regular wide QRS complex tachycardia between 1991 and 2006.

A positive response: was defined as an observed change in rhythm including temporary atrioventricular conduction block or tachycardia termination.

A primary adverse event: was defined as emergent electrical or medical therapy instituted in response to an adverse adenosine effect.

A rhythm diagnosis was made in each case. The characteristics of adenosine administration as a test for a supraventricular as opposed to ventricular tachycardia were determined, and the adverse event rates were calculated.

Results:

A total of 197 patients were included: 104 (90%) of 116 and two (2%) of 81 supraventricular tachycardia and ventricular tachycardia patients demonstrated a response to adenosine, respectively.
The odds of supraventricular tachycardia increased by a factor of 36 after a positive response to adenosine.
The odds of ventricular tachycardia increased by a factor of 9 when there was no response to adenosine.
The rate of primary adverse events for patients with supraventricular tachycardia and ventricular tachycardia was 0 (0%) of 116 and 0 (0%) of 81 respectively.

Conclusions: Adenosine is useful and safe as a diagnostic and therapeutic agent for patients with regular wide QRS complex tachycardia.

Reference:

Adenosine for wide-complex tachycardia: Efficacy and safety- Critical Care Medicine: September 2009 - Volume 37 - Issue 9 - pp 2512-2518

2009-08-24T10:27:00.000-07:00

Monday August 24, 2009

Q; What are the 3 mechanisms by which lactulose improve hepatic encephelopathy?

Answer:

The conversion of Lactulose to lactic acid results in acidification of the gut lumen. This favors conversion of NH4 + to NH3 and the passage of NH3 from tissues into the lumen.
Gut acidification inhibits ammoniagenic coliform bacteria, leading to increased levels of nonammoniagenic lactobacilli.
Lactulose also works as a cathartic, reducing colonic bacterial load.

2009-08-23T21:24:00.000-07:00

Sunday August 23, 2009

Managing chest tube (drainage system)

2009-08-22T07:33:00.001-07:00

Saturday August 22, 2009

Case: 69 year old male admitted to ICU for community acquired pneumonia and did well with treatment. Over last 24 hours received Thorazine for persistent hiccups. While revewing morning EKG, you noticed following changes?

Answer: Phenothiazines induced EKG changes.

Phenothiazines induced EKG changes seen in approximately 50% of patients receiving "therapeutic" doses.

Mimics hypokalemia
Prominent U waves
Low amplitude T waves or T wave inversion
ST segment depression
Prolonged QT interval

Phenothiazines include Chlorpromazine hydrochloride (Thorazine), Prochlorperazine (Compazine), Promethazine hydrochloride (Phenergan) , Thioridazine hydrochloride (Mellaril) , Trifluoperazine hydrochloride (Stelazine) and others

2009-08-21T06:33:00.000-07:00

Friday August 21, 2009 (pediatric pearl day)
Uniqueness of Neonatal/ Infantile Myocardium compared to adult myocardium

Neonatal myocardium has a large supply of mitochondria, nuclei and endoplasmic reticulum to support cell growth and protein synthesis but these are non-contractile tissues which render the myocardium stiff and non-compliant. This may impair filling of the left ventricle and limit the ability to increase the cardiac output by increasing stroke volume (Frank Starling mechanism). Stroke volume is therefore relatively fixed and the only way of increasing cardiac output is by increasing heart rate. The cardiac index (defined as the cardiac output related to the body surface area to allow a comparison between different sizes of patients) is increased by 30-60 percent in neonates and infants to help meet the increased oxygen consumption.

The sympathetic nervous system is not well developed predisposing the neonatal heart to bradycardia. Anatomical closure of the foramen ovale occurs between 3 months and one year of age.

Neonatal myocardium is distinctly more sensitive to extracellular calcium levels than is mature myocardium. This has been ascribed to the poorly developed sarcoplasmic reticulum of neonatal myocardium and is dependent on serum calcium to maintain optimal contractility. Calcium is an important inotrope in newborns and its optimization is critical in low cardiac output syndrome.

2009-08-20T03:59:00.000-07:00

Thursday August 20, 2009
Armour Thyroid

Armour Thyroid is a "natural" thyroid replacement medication that is available by prescription. It is made from thyroid glands of pigs and contains two different thyroid hormones. It provide 38 mcg levothyroxine (T4) and 9 mcg liothyronine (T3) per grain of thyroid.

2009-08-19T04:36:00.000-07:00

Wednesday August 19, 2009

Q; 52 year old female presented with headache and vision change. You did retinal exam. Your Diagnosis?

Hypertensive retinopathy (Malignant phase)

The detection of hypertensive retinopathy with the use of an ophthalmoscope has long been regarded as part of the standard evaluation of persons with hypertension. This clinical practice is supported by both previous and current reports of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC), which list retinopathy as one of several markers of target-organ damage in hypertension.

2009-08-18T14:23:00.000-07:00

Tuesday August 18, 2009

Q; Succinylcholine is contraindicated (relatively) for intubation in which poisoining?

Answer: Organophosphate poisoining.

Organophosphate may potentiate effects of succinylcholine. Succinylcholine is relatively contraindicated in Organophosphate poisoining.

2009-08-17T11:24:00.001-07:00

Monday August 17, 2009

Q; Is menstrual bleeding a contraindication to thrombolytic therapy in Acute MI or Stroke?

Answer: No

There may be a clinically significant increase in the risk of moderate bleeding during menstruation. But lifesaving benefit of thrombolytic therapy for acute myocardial infarction should generally not be withheld because of active menstruation. Potential patients should be advised that they might require transfusion for increased menstrual flow.

2009-08-16T14:13:00.000-07:00

Sunday August 16, 2009
Causes of False-Positive Troponin Results (Lab interference / errors)

Heterophile antibodies
Human anti-mouse antibodies
Autoantibodies
Fibrin clots
Rheumatoid factor
Microparticles in specimen
Interference by endogenous components in blood (bilirubin, hemoglobin, lipemia)
High concentration of alkaline phosphatase
Immunocomplex formation
Analyzer malfunction

2009-08-15T09:37:00.000-07:00

Saturday August 15, 2009
Ramsay Sedation Scale

Clinical Score depending on Level of Sedation Achieved

6 - Asleep, no response
5 - Asleep, sluggish response to light glabellar tap or loud auditory stimulus
4 - Asleep, but with brisk response to light glabellar tap or loud auditory stimulus
3 - Patient responds to commands
2 - Patient cooperative, oriented, and tranquil
1 - Patient anxious, agitated, or restless

2009-08-14T10:35:00.000-07:00

Friday August 14, 2009 (pediatric pearl)
Uniqueness of Pediatric Upper Airway

Previous related pearls:
Uniqueness of Pediatric Lower Airway - Part 1
Uniqueness of Pediatric Lower Airway - Part 2

The frequency of acute respiratory failure is higher in infants and young children than in adults for several reasons. This difference can be explained by defining anatomic compartments and their developmental differences in pediatric patients that influence susceptibility to acute respiratory failure.

The extrathoracic airway (extending from the nose to the subglottic region of the trachea) has significant differences in pediatric versus adult patients include the following:

Neonates and infants are obligate nasal breathers until the age of 2-6 months because of the proximity of the epiglottis to the nasopharynx. Nasal congestion can lead to clinically significant distress in this age group.
The small size of the airway is one of the primary differences in infants and children younger than 8 years compared with older patients.
Infants and young children have a large tongue that fills a small oropharynx.
Infants and young children have a cephalic larynx. The larynx is opposite vertebrae C3-4 in children versus C6-7 in adults. Larynx cone-shaped: narrowest at subglottic cricoid ring - Softer, more pliable: may be gently flexed or rotated anteriorly
The epiglottis is larger and more horizontal to the pharyngeal wall in children than in adults. The cephalic larynx and large epiglottis can make laryngoscopy challenging.
Vocal cords slanted: anterior commissure more inferior
Infants and young children have a narrow subglottic area. In children, the subglottic area is cone shaped, with the narrowest area at the cricoid ring. A small amount of subglottic edema can lead to clinically significant narrowing, increased airway resistance, and increased work of breathing. Older patients and adults have a cylindrical airway that is narrowest at the glottic opening.
In slightly older children, adenoidal and tonsillar lymphoid tissue is prominent and can contribute to airway obstruction.
Upper airway contributes 50% to total airway resistance compared to about 20% in adults.
Infant head is relatively larger: naturally flexed in supine position. Extension of head may result in tracheal extubation; while flexion may lead to main stem intubation.

2009-08-13T10:25:00.000-07:00

Thursday August 13, 2009
KING LT (laryngeal tube) intubation

The king airway is a blind insertion, just like combi tube. It's a double lumen airway. It occludes the esophagous and ventilates through the opening on the side of the tube. King LT is an advanced airway where ventilations through it go into the trachea, and the esophagus is occluded.

2009-08-12T19:35:00.000-07:00

Wednesday August 12, 2009
Fluid Resuscitation and Intra-Abdominal Hypertension

2009-08-11T19:25:00.000-07:00

Tuesday, August 11, 2009
Intracerebroventricular Administration of Drugs

Reference: Cook AM, et al. Pharmacotherapy 2009;29(7):832

Guidelines do not currently exist for drug administration via the intracerebroventricular route, however, a good review was just published in Pharmacotherapy.

Methods of administration include:

· Directly into the lumbar cistern (thecal sac), Intrathecally

o Low risk and easily performed at bedside, however, requires separate puncture for subsequent doses which increases risk of infection

· Directly into the lateral ventricle

o Repeated taps not routinely performed due to risk of neurovascular injury or intracranial hemorrhage

· Permanent access through implanted catheter connected to reservoir

o e.g. Ommaya reservoir

· Ventriculostomy

o Ideal for situations requiring limited time for CSF drainage or intraventricular drug administration. Should use caution and close monitoring of intracranial pressure

Considerations for drug administration:

· Volume of solution

o Affects the distribution or clearance of drug. Increasing volume would result in an alteration in the normal intracranial components to maintain normal intracranial pressure.

· Rate of instillation

o Slow instillation recommended to allow for extracellular fluid displacement to prevent tissue damage. Recommend small volumes <3ml>

2009-08-10T19:16:00.001-07:00

Monday August 10, 2009
Quick and Dirty on Vasopressors and Inotropes

Vasopressor activity on the following receptors are agonistic:
a1 receptors-- peripheral arteries-- peripheral vasoconstriction
b1 receptors-- coronary smooth muscle-- increased heart rate and contractility
b2 receptors—smooth muscle—increases force of contractility in the heart
DA1 receptors-- renal, mesenteric, and coronary beds-- vasodilation and increase urine output.
V1, receptors-- vascular smooth muscle--vasopressor;
V2 receptors-- renal collecting duct system--natural diurectic
Vasopressors:
Dopamine: receptor action is dependent on dose… DA1 1-5 microgram/kg/min + HR; b1 5-10 microgram/kg/min, ++ HR, + MAP, + CO; a1 > 10 microgram/kg/min + SVR, + MAP, + HR, +CO
Epinephrine: b1 >> a1 1-20 microgram/min ++ SVR, +MAP, +HR, +CO
Norepinephrine: a1 > b1 1-80 microgram/min, ++ SVR, ++MAP , ?+HR, ?+CO
Phenylephrine: a1 2-200 micrograms/min; ++SVR, +MAP, ?+HR, ?+ CO
Vasopressin: V1 V2 0.04 units/min ++SVR, +MAP, ?+HR, ? +CO

Inotropes:

Dobutamine: b1, b2 2-20 microgram/kg/min ááCO áHR âSVR ?âMAP

Milrinone: PDE inhibitor in vascular and cardiac smooth muscle which improves calcium handling causing dilation. In cardiac muscle, the inhibition of phosphodiesterase results in increased levels of cAMP, resulting in increased chronotropic and inotropic effects.

Reference:

Dellinger RP. Crit Care Med 2008;36(1):296

2009-08-09T10:35:00.000-07:00

Sunday August 9, 2009
Picture Diagnosis

What is your diagnosis?

Hint is Arrow

.

Answer: Pneumothorax after central line placement.

Note the abnormally placed central line extending upwards from subclavian vein into internal jugular vein along with pneumothorax.

2009-08-08T10:46:00.000-07:00

Saturday August 8, 2009

Q; Troponins, once secreted, remains elevated for how many days?

Answer: Troponin, once secreted, remains elevated for 7-10 days.

2009-08-07T22:43:00.000-07:00

Friday August 7, 2009 (pediatric pearl)
Uniqueness of Pediatric Lower Airway - Part 2

(see Uniqueness of Pediatric Lower Airway - Part 1 here)

The frequency of acute respiratory failure is higher in infants and young children than in adults for several reasons. This difference can be explained by defining anatomic compartments and their developmental differences in pediatric patients that influence susceptibility to acute respiratory failure.

The intrathoracic airways and lung include the conducting airways and alveoli, the interstitia, the pleura, the lung lymphatics, and the pulmonary circulation. Noteworthy differences among pediatric children include the following:

Infants and young children have fewer alveoli than do adults. The number dramatically increases during childhood, from approximately 20 million after birth to 300 million by 8 years of age. Therefore, infants and young children have a relatively small area for gas exchange.
The alveolus is small. Alveolar size increases from 150-180 to 250-300 µm during childhood.
Collateral ventilation is not fully developed; therefore, atelectasis is more common in children than in adults. During childhood, anatomic channels form to provide collateral ventilation to alveoli. These pathways are between adjacent alveoli (pores of Kohn), bronchiole and alveoli (Lambert channel), and adjacent bronchioles. This important feature allows alveoli to participate in gas exchange even in the presence of an obstructed distal airway.
Smaller intrathoracic airways are more easily obstructed than larger ones. With age, the airways enlarge in diameter and length.
Infants and young children have relatively little cartilaginous support of the airways. As cartilaginous support increases, dynamic compression during high expiratory flow rates is prevented.

2009-08-06T23:56:00.000-07:00

Thursday August 6, 2009
Heparin Induced HyperKalemia

Hyperkalemia from Heparin is a well know phenomenon and has been detected particularly on geriatric, renal insufficient and diabetic patients. Hyperkalemia can be anywhere from .3 to 1.7 mEq/Litre. It usually occurs around on day 3 with SQ heparin (as for DVT prophylaxis) but can occur early with IV heparin 1,2,3,4.

Hyperkalemia has been reported with low- molecular weight heparins too but risk is low 5, 6, 7.

Mechanism of action: Heparin induce hypoaldosteronism and can subsequently lead to hyperkalemia 6.

Treatment: Best thing is to discontinue the culprit but if heparin is absolutely required, fludrocortisone (.1 mg/day) has been reported to be effective in heparin-induced hyperkalemia 8.

References: Click to get abstracts/articles

1. Case report - Heparin-induced hyperkalemia after cardiac surgery - Ann Thorac Surg 2002;74:1698-1700

2. Heparin-induced hyperkalemia -The Annals of Pharmacotherapy: Vol. 24, No. 3, pp. 244-246.

3. Heparin Induced HyperKalemia - Endocrine Abstracts (2002) 4 P26

4. Heparin-Induced Hyperkalemia Confirmed by Drug Rechallenge. American Journal of Physical Medicine & Rehabilitation. 79(1):93-96, January/February 2000.

5. Early onset of hyperkalemia in patients treated with low molecular weight heparin: a prospective study - Pharmacoepidemiol Drug Saf.2004 May;13(5):299-302.

6. Effect of Low-Molecular-Weight Heparin on Potassium Homeostasis - Pathophysiology of Haemostasis and Thrombosis 2002;32:107-110

7. Low Molecular Weight Heparins Can Lead To Hyperkalaemia The Internet Journal of Geriatrics and Gerontology . 2005. Volume 2 Number 2.

8. Fludrocortisone for the treatment of heparin-induced hyperkalemia - The Annals of Pharmacotherapy: Vol. 34, No. 5, pp. 606-610

2009-08-05T20:59:00.000-07:00

Wednesday August 5, 2009

Scenario: 25 year old patient presented to the emergency room with complaint of 2 days history of muscular weakness which is symmetric and descending and diplopia. He denies any fever or chills. He does give the history of having injury to the face. He works as marine driller. His symptoms are progressively getting worse. His vitals signs reveal no fever, and bradycardia with the heart rate of 48 and blood pressure of 120/80 mm hg. His Slow vital capacity was 1 liter (33% of predicted). He was admitted in intensive care unit.

Diagnosis: Botulism (110 cases in US per year with 3 percent being wound Botulism)

Differential diagnosis: Mysthenia Gravis, Lambert-Eaton syndrome, Guillain-Barre’s syndrome, poliolmyelitis, Ticks paralysis, heavy metal intoxication.

Botulism has an acute onset with bilateral cranial neuropathies and symmetric descending weakness. Key feature include:

Patient is afebrile
Symmetric neurological deficit
Patient is responsive
Normal or slow heart rate and normal blood pressure
No sensory deficit
Blurred vision

Treatment:

Equine serum botulism antitoxin
Penicillin G intravenously 3 grams every 4 hours

2009-08-04T22:09:00.000-07:00

Tuesday August 4, 2009
Heparin rebound phenomenon

Heparin rebound phenomenon, is considered to be a contributive factor in excessive postoperative bleeding after cardiac surgery. It is due to the reappearance of anticoagulant activity despite adequate neutralization with protamine.This phenomenon is well known since atleast last 45 years 1.

The underlying etiology is due to the fact that a significant amount of heparin remains bound to plasma proteins and escape neutralization by protamine. Later this heparin get released and may contribute to excessive postoperative bleeding after cardiac surgery. Though logically, the treatment is more administration of prtoamine but caution should be taken as high and inappropriate protamine dose may lead to 'acute' pulmonary hypertension 2 and interestingly failed to show decrease in blood product adminstration 3 or any difference in the thrombelastographic profiles or coagulation screen (PT, PTT, ACT and platelets) 2. Also life threatening protamine reactions is another risk need to be considered 5.

Note: This Heparin rebound phenomenon is different from Rebound increase in Thrombin Generation and Activity after cessation of intravenous heparin in patients with acute coronary syndromes which is also often referred as heparin rebound phenomenon 4.

References: click to get abstract/article

1. Heparin rebound phenomenon in extracorporeal circulation - Surg Gynecol Obstet.1962 Aug;115:191-8.

2. Heparin rebound phenomenon--much ado about nothing? - Blood Coagul Fibrinolysis. 1992 Apr;3(2):187-91.

3. Can extra protamine eliminate heparin rebound following cardiopulmonary bypass surgery? - J Thorac Cardiovasc Surg 2004;128:211-219

4. Rebound Increase in Thrombin Generation and Activity After Cessation of Intravenous Heparin in Patients With Acute Coronary Syndromes - Circulation. 1995;91:1929-1935.

5. Life Threatening Protamine Reactions In Cardiac Surgery: Literature Review With A Case Report - The Internet Journal of Thoracic and Cardiovascular Surgery. 2005. Volume 7 Number 1.

2009-08-03T22:20:00.000-07:00

Monday August 3, 2009
Atenolol in renal failure

One must use caution while prescribing atenolol to patients with renal insufficiency. The elimination half-life of atenolol is extensively prolonged in patient with renal failure. The normal half life of atenolol is 6 to 7 hours; however, in renal failure patients the half-life may be extended to more than 100 hours 2.

The recommended dosage are following:

CrCl 35 mL/min or greater - normal dosing
CrCl 15 - 35 mL/min - MAX. dose 50 mg orally QD
CrCl less than 15 mL/min - MAX. dose 25 mg orally QD
Hemodialysis: 25-50 mg orally after each dialysis session.

Treatment of atenolol overdose in a patient with renal failure is recommended with serial hemodialysis and charcoal hemoperfusion 3. On the contrary, metoprolol is extensively metabolized via the hepatic system.

References:

1.Atenolol-DOSAGE AND ADMINISTRATION - rxlist.com

2.Atenolol kinetics in renal failure - Clin Pharmacol Ther. 1980 Sep;28(3):302-9

3. Treatment of atenolol overdose in a patient with renal failure using serial hemodialysis and hemoperfusion and associated echocardiographic findings Vet Hum Toxicol. 2000 Aug;42(4):224-5.

2009-08-02T03:53:00.000-07:00

Sunday August 2, 2009
Why Arixtra doesn't cause HIT (Heparin induced thrombocytopenia)

ARIXTRA (Fondaparinux) is not a heparin. ARIXTRA is the first and only pentasaccharide antithrombotic agent inhibiting only factor Xa

2009-08-01T00:08:00.000-07:00

Saturday August 1, 2009

Procedure tip - Straight to Cuff Stylet Shaping