Saturday October 28, 2006
Q: Which poison smell's like "Almond"?
And which poisoning presents with garlic odor?
A: Organophosphate poisoning
Friday October 27, 2006Unplanned
extubations (UE)Unplanned extubations in ICUs have been reported anywhere from 1-16% with higher incidence
in surgical ICUs.
Unplanned extubations have been tagged as one of the "outcome measures" in famous article published
earlier this year - "Intensive care unit quality improvement: A how-to guide for the interdisciplinary team"
To improve the UE rate, one study was done at at St. Joseph’s
Hospital in Marshfield, Wis., where a committee comprised of an intensivist, the respiratory therapy staff and the nursing
staff looked into frequency of unplanned extubations in the adult ICUs during a 6-month period (see the incident report form
in reference). After obtaining data, committee took 2 steps approach.
As a first step, the committee examined various
endo-tracheal tube (ETT) holders available, looking at design, securability, ease of application, durability, ease to maintain
the integrity of the oral mucosa and to maintain skin integrity beneath the area of application. After selecting the product,
second step was taken and extensive in-service training sessions were done over 2 weeks spreading over all shifts for the
nursing and the respiratory staff including right technique, taping, application of an adhesive skin preparation etc.
of UE was compared 6 months preceding staff education with the 6 months after staff education. In the CCU/ MICU, the unplanned
extubation rate decreased from 2.14% to 0.87% and in the SICU, the unplanned extubation rate decreased from 2.32% to 1.0%
(10 extubations in 1000 days) after the education 2.
References: click to get abstract/article
1. Intensive care unit quality improvement: A "how-to" guide for the
interdisciplinary team - Critical Care Medicine. 34(1):211-218, January 2006
2. Unplanned Extubation in Adult Critical Care - Critical Care Nurse. 2004;24: 32-37
3. The Drive to Survive, Unplanned Extubation in the ICU - Chest. 2005;128:560-566
emThursday October 26, 2006
Neuromuscular blocking agents (NMBAs) in ARDS
We all dread and think twice before using
NMBAs. But in this month (November 2006) of Critical Care Medicine 1,
there is a prospective randomized trial of 36 patients published from france showing postive effect of neuromuscular blocking
agents in patients presenting with acute respiratory distress syndrome.
A total of 36 patients with acute respiratory
distress syndrome (Pao2/Fio2 ratio of less than / = 200 at a PEEP of more than/ = 5 cm H2O were included within 48 hrs of
ARDS onset. Patients were randomized to receive
- conventional therapy plus placebo (n = 18) for 48 hrs or
- conventional therapy plus NMBAs (n = 18) for 48 hrs.
Both groups were ventilated with low tidal volume between 4 and 8 mL/kg.
Bronchoalveolar lavages and blood
samples were performed, before randomization and at 48 hrs, to determine the concentrations of
- tumor necrosis factor-α,
- interleukin (IL)-1β,
- IL-6, and
Pao2/Fio2 ratio was evaluated before randomization and at 24, 48, 72, 96, and 120 hrs.Reference: click to get abstract
At 48 hrs after randomization,
pulmonary concentrations of IL-1β, IL-6 and IL-8 were lower in the NMBA group as compared with the control group. Similar
pattern noticed in serum samples. Importantly, a sustained improvement in Pao2/Fio2 ratio was
observed in the NMBA group upto 120 hours.
Neuromuscular blocking agents decrease inflammatory response in
patients presenting with acute respiratory distress syndrome - Critical Care Medicine. 34(11):2749-2757, November 2006
Wednesday October 25, 2006Re: Calcium Channel blocker overdose
Editors' note: In response to our pearl on Saturday October 21, 2006 regarding Calcium Channel Blocker overdose, we received following feedback which is worth sharing.
"...First, I want to congratulate you on a most excellent website. I always enjoy reading
the daily pearls. The daily pearl for 10/21/06 is regarding CCB overdose and potential treatments with glucagon and amrinone.
One very important treatment strategy for Beta-blocker (BB) or Calcium-Channel-Blocker (CCB) overdoses resistant to the above
traditional antidotes is the use of hyperinsulin/euglycemia therapy. (I have personally used this on a propranolol overdose
with much success). This is the treatment of the future and widely reccommended by the toxicology folks and should always
be noted as a potential salvage therapy when the traditional approaches fail. I have attached 2 recommended readings 1, 2 regarding HDIDK (High Dose Insulin Dextrose Potassium) in regards to
treatment of CCB and BB toxicity.Thanks,
St Bernards Hospital,Midwestern University / Chicago College of Osteopathic Medicine
Residency ProgramChicago, IL
As both attached references are from subscription journals, we put link to abstracts
below but there is a free review available: Treatment of poisoning caused by ß-adrenergic and calcium-channel
blockers , GREENE SHEPHERD, PHARM.D., DABAT, Clinical Associate Professor, Medical College of Georgia,
Augusta, GA (reference: American Journal of Health-System Pharmacy, Vol. 63, Issue 19, 1828-1835)Recommended Reading:
Treatment of Calcium-Channel–Blocker Intoxication with Insulin
Infusion - The New England Journal of Medicine , May 31, 2001, Volume 344:1721-1722
High-Dose Insulin Therapy for Calcium-Channel Blocker Overdose - Shepherd and Klein-Schwartz Ann Pharmacother.2005; 39: 923-930
Tuesday October 24, 2006CR-BSIsOne of the parameter or measurement of ICU is the decreasing rate of CR-BSIs. (Central line catheter-related
bloodstream infections). CR-BSIs are calculated or presented usually per 1000 central line-days. The formula for the CR-BSI
Rate per 1000 catheter days is:Total no. of CR-BSI cases / No. of catheter
days x 1000 = CR-BSI rate per 1000 catheter daysFor example:
In a given month, you had 100 central lines in your ICU and each stayed there for 4
days. Your total no. of catheter days are 100 X 4 = 400 days. Now you confirmed 15 cases of CR-BSIs. The CR-BSI Rate per 1000
catheter days in your ICU for that given month is 15 / 400 x 1000 = 37.5
On average per IHI report approximately 5.3
catheter-related bloodstream infections occur per 1,000 catheter days in ICUs.
Now your goal should be to decrease
this number for your ICU.
Bonus Pearl: As against common belief, application
of ointment at catheter insertion site does not decrease the infection rate. Actually application of antibiotic ointments
(e.g., bacitracin) to catheter-insertion sites increases the rate of catheter colonization by fungi and promotes the emergence
of antibiotic-resistant bacteria.
Related Site: Implement the Central Line Bundle (IHI)Recommended Reading:
Preventing Complications of Central Venous Catheterization, David
C. McGee, M.D.,, NEJM, March 03, Volume 348:1123-1133.
Monday October 23, 2006Hypotension
in ED and Sudden Unexpected In-hospital Mortality !
Interesting study published
this month in 'chest' though not sure how it impacts the overall management as editorial in the same issue asked: "But despite the strength of the observational data in this study, there is still one all-important
question that will require additional research and remains as-of-yet unanswered: "now what should you DO?".
Nontrauma Emergency Department patients (age above 17) were divided into 2 groups:
Deaths were classified as sudden and unexpected by independent observers (using explicit criteria - available in article).
- "Exposures" who had any systolic BP less than 100 mm Hg in the ED ( n = 887)
- "Non-exposures" all had SBP more than or equal to 100 mm Hg in the ED (n = 3903)
'Exposures' were more likely to die in the hospital compared with nonexposures as well as 'Exposures'
were more likely to have sudden and unexpected death compared with nonexposures (2% vs 0.2%). Exposure to hypotension was
as an independent predictor of in-hospital mortality. Study concluded that patients exposed
to hypotension (even single reading of less than 100 mm Hg) had a significantly increased risk of death during hospitalization,
despite been stabalized later in ED or hospital.As asked in the discussion
of this study by authors and being an intensivist, here is the million dollar question?: "Do they need to get admit to higher
level of care such as an ICUs?". Reference: click
to get abstract
Emergency Department Hypotension Predicts Sudden Unexpected In-hospital
Mortality Chest. 2006;130:941-946.
Sunday October 22, 2006
hypokalemia in presence of hypomagnesemiaQ; Why
potassium cannot be fixed if hypomagnesemia remains uncorrected?A;
Hypomagnesemia causes kidney to continue to loose potassium, thats why hypokalemia cannot be
fixed if hypomagnesemia remains uncorrected. It can be confirmed with TTKG calculation.Related previous pearl: TTKG
Saturday October 21, 2006
Calcium Channel blocker overdose
Q; Which 'Calcium Channel Blocker'
overdose may not produce noticeable hypotension but severe heart blocks (and may decieve the diagnosis) ?
A; Diltiazem. Most of the CCB overdose produce significant hypotension
as expected but Dilitiazem may decieve you by just producing heart blocks.
2 important pearls in treating CCB overdose beside calcium infusion and standard hemodynamic support.
1. 5 - 15 mg IV Glucagon is a viable adjuvant treatment in calcium
channel bloker overdose. But it is advisible to administer Glucagon before calcium infusion is given, as erratic blood calcium
level may mask full effect of glucagon. Glucagon via cAMP increases cardiac contractility and counter heart blocks.
2. Consider adding Inocor (amrinone) infusion. It is a Phosphodiesterase
inhibitor and has 2 actions. 1) it delays release of calcium into the cell 2) it increases cardiac contractility via cAMP.
Friday October 20, 2006High-volume
hemofiltration as salvage therapy in severe hyperdynamic septic shockThere tend
to be a continue interest in high-volume hemofiltration for sepsis and every now and then we see studies in respected journals.
Overall, literature tends to favor high-volume hemofiltration as a salvage therapy in severe septic shock and if nothing is
working, why not to use it as a last resort?
Recently one study of 20 patients published from Chile to evaluate the
effect of short-term (12 hours) high-volume hemofiltration (HVHF) in reversing progressive refractory hypotension and hypoperfusion
in patients with severe hyperdynamic septic shock unresponsive to traditional sepsis therapy.
11 of 20 patients were found
to be "responders" with decrease in decreased norepinephrine dose, lactate levels and heart rates. Arterial pH improved significantly.
Hospital mortality was 18% (2/11) in responders but remained high with 67% in 'non-responders' ! Interestingly only
one single 12-h HVHF session was given.
Study concluded that a single session of HVHF may be use with benefit as salvage
therapy in severe refractory hyperdynamic septic-shock patients.Study to watch: IVOIRE (hIgh Volume in Intensive Care)
High-volume hemofiltration as salvage therapy in severe hyperdynamic
septic shock - Intensive Care Medicine - Volume 32, Number 5 / May, 2006
Thursday October 19, 2006Q; How many percentage of PA catheter failed to obtain Wedge pressure (PAOP)
?A; 25% 1
(so don't get dishearted and use PADP as a guide)Related Previous Pearl:
Pulmonary Artery Diastolic-Pulmonary Wedge Pressure GradientReference:
The ICU Book -Paul Marino - 3rd edition
- Page 168
Wednesday October 18, 2006
Take home message about ICU scores
Mutiple scores have been developed to predict severity,
prognosis, and outcome of diseases in ICU. (See all scores here from icumedicus site). All of these scores have their own flaws and none of them are perfect, like lactic acid
level, a significant serial marker in ICU is not part of even APACHE IV score (Glucose level is now included). It takes a
lot of effort and trained staff to implement these scoring systems. So what's the significance of using these various scores?
scores serve the purposes of assessing therapies, quality control and assurance, and of an economic evaluation of intensive
care as a whole. Like using these scores, if your's ICU lenght of stay or mortality rate is more than the predicted - it requires
your attention in assessing therapies and quality assurance. Although these scores (like MPM) have been said to predict mortality
in individual patients but in real life, note (and note again !) that these scores SHOULD NOT be applied in individual
patients to predict mortality. This may create a psychological bias towards an individual patient.
Dr. Jack Zimmerman
and coll. , looked into data of 116,209 patients for predicting ICU length of stay with The APACHE IV scores and come to the
same conclusion that: "The APACHE IV model provides clinically useful ICU length of
stay predictions for critically ill patient groups, but its accuracy and utility are limited for individual patients. APACHE
IV benchmarks for ICU stay are useful for assessing the efficiency of unit throughout and support examination of structural,
managerial, and patient factors that affect ICU stay".Reference: click to get abstract
A randomized, controlled trial of the role of weaning predictors
in clinical decision making -Critical Care Medicine. 34(10):2530-2535, October 2006.
Tuesday October 17, 2006Q; So what should be the target vancomycin trough (or random)
level ? A: This month a retrospective study of 102 patients with MRSA has been published into 'chest' looking
into benefit of higher vancomycin trough or random level (more than 15 µg/mL). The stratification of the vancomycin trough
levels yielded no relationship with hospital mortality. Study found no evidence that higher vanco trough levels correlated
with hospital outcome. 'Vanco level' between 5 to 15 µg/mL seems to be a reasonable
target range.Reference: click to get abstract
Predictors of Mortality for Methicillin-Resistant Staphylococcus
aureus Health-Care–Associated Pneumonia - Specific Evaluation of Vancomycin Pharmacokinetic Indices - Chest. 2006;130:947-955
Monday October 16, 2006Scenario:
You have a patient in unit whose blood sugar is hard to control despite aggressive insulin
therapy. You wrote an order to prepare all drips and medications in either 0.9 or 0.45 NS (Normal Saline), as far as compatible.
Next day, you noticed that pharmacy continue to prepare NOREPINEPHRINE (LEVOPHED) drip in mix with D5W. What do you think
Answer: NOREPINEPHRINE (LEVOPHED) is less stable in normal saline (loose its potency from oxidation). Dextrose containg
solution is preferred as the dextrose protects against oxidation of the norepinephrine and keep it active and stable.
Sunday October 15, 2006
Burnout among intensivists !!
We tried to explore literature to find studies related
to burnout rate among intensivists. Interestingly, we found only 2 scientific studies each related to adult and pediatric
intensivists. Both studies are available in references. These studies were done about 10 years ago and we assume
that burnout rate is even higher today in view of more demand, recognition and acceptance of intensivist led model.
Adult Study:248 physicians responded to tool of Maslach Burnout Inventory survey. MBI survey looks into 3 aspects of burnout
- Emotional exhaustion
- Personal accomplishment
A third of respondents scored in the high range of the emotional exhaustion, 20.4% of respondents scored in the high range
of depersonalization score, and 59% scoring in the low range of personal achievement scores.
In this study, the Burnout Scale of Pines and Aronson was used and 389 pediatric intensivists responded. 11 years ago, 50% of pediatric intensivists were at risk of burned out. Interestingly, Overall, there was
no association between having fellows; having protected time for research and publications; frequency of being called at home;
frequency of returning to the hospital when called at home; or call schedule. (Routine exercise was associated with lower
In newly released US Department of Health and Human Services Report to Congress: The Critical Care Workforce: A Study of the Supply and Demand for Critical
Care Physicians - it has been predicted that by 2020, the demand for intensivists would likely increase by 129
percent above the current supply. The 2 major reasons for shortage would be the aging population and the increased utilization
of intensivists(including burnout). Is it time for another survey from SCCM or ACCP ?
Related previous pearls:
Optimum patients' load for intensivist
References: click to get abstract/article
1. Burnout in the internist--intensivist. - Intensive Care Med.1996 Jul;22(7):625-30.
2. Physician burnout in pediatric critical care medicine. - Crit Care Med. 1995 Aug;23(8):1425-9
Saturday October 14, 2006
Q: Which phase of respiration on CXR is better to detect pneumothorax (like
after inserting central venous catheter)- inspiration or expiration ?A: Expiration
Inspiration or expiration doesn't effect
the volume of air in pleural space and pneumothorax can be detected better in expiration with less air volume in lung parenchyma,
visually magnifying the air in pleural area.
Friday October 13, 2006
Betdadine or Chlorhexidin ?It
is so true that scientific knowledge takes on average 17 years to travel from bench to bedside. Most of us grew up using Betadine
(povidone-iodine) for bedside procedures but Dennis Maki published a study about 15 years ago in Lancet 1 randomizing solutions for skin preparation for 668 catheters, comparing
2% chlorhexidine, 10% povidone-iodine (betadine), and 70% alcohol. Chlorhexidine was associated with the lowest incidence
of catheter-related-blood-stream-infections (CRBSI) with 2.3 per 100 catheters followed by Alcohol with 7.1 and povidone-iodine
with 9.3 infections per 100 catheters. Another meta-analysis of 8 studies involving about 4000 catheters published in 2002
confirmed the above results 2.Centers for Disease Control (CDC) as well as IHI (Institutefor Healthcare
Improvement) now recommends to use 2% chlorhexidine instead of povidone-iodine(Betadine).
Related previous pearl: Suture at central venous catheter site - a risk?References:
1. Prospective randomised trial of
povidone-iodine, alcohol, and chlorhexidine for prevention of infection associated with central venous and arterial catheters.
- Lancet 1991;338:339-43. Maki DG, Ringer M, Alvarado CJ.
2. Chlorhexidine compared with povidone-iodine solution for vascular
catheter-site care: a meta-analysis. (pdf) - Ann Intern Med 2002;136:792-801.
October 12, 2006
Why that PICC is purple ? Power PICC
The use of multidetector CT scanners requires rapid injection of radiographic contrast media. Injecting
contrast via regular PICC may cause rupture of catheter (rupture is recently reported with central venous catheter also 2) as well as it compromise clarity of images as target organ receives a
bolus of the contrast media in a less concentrated dose. Power PICC is a new version of PICC line, identified by purple color
and especially designed to inject radiological contrast media.
The maximum flow
rate that can be used for power injection of contrast media through a PowerPICC is 5ml/sec but upto 2ml/sec is said to be
satisfactory for imaging purposes 1. The maximum pressure the power
injector should be set at 300 psi.
Again, you can recognize the PICC as a power
injectable PICC, by its purple color port. The picture below is from www.bardaccess.com (makers of PICC lines). You can have more information from website also.
Bonus Pearl: Remember, central lines (TLC or PICC
lines) are technically not ideal for IVF boluses due to longer length and smaller radius. 2 Large bore (say 18 gauge) peripheral
IVs or one large bore central IV (cordis / introducer use for swan placement) are real placements for aggressive resuscitation
(due to bigger radius and shorter length). [As per Hagen-Poiseuille equation just 2 fold increase in radius increase flow
by 16 fold but 2 fold increase in length decrease flow by 50%].
Reference: click to get article
1. Power Injection of Contrast Media via Peripherally Inserted Central
Catheters for CT - Journal of Vascular and Interventional Radiology 15:809-814 (2004)
Central line pump infusion and large volume mediastinal contrast
extravasation in CT - British Journal of Radiology (2006) 79, e75-e77
Wednesday October 11, 2006Q; 42 yr old male admitted with Guillain-Barré Syndrome and intubated due
to rapidly falling vital capacity. Pt otherwise remain fairly stable and sedated with average dose of 5 mg/kg/hr Propofol.
Unfortunately, patient failed 5 days of Plasma exchange therapy. On day 6, pt develop exacerbation of his baseline asthma
and was started on IV solumedrol but steroids were discontinued next day on neurology’s recommendation as it may prolong
recovery from GBS. All labs and clinical exam otherwise remain stable including mental status which was assessed briefly each
morning while off sedation. DVT and GI prophylaxis on place. Enteral feeding started on day 2. Bedside percutaneous trach
and PEG has been planned.
While on ICU shift on night of day 7, you noticed
some downward trend on BP but as labs and exam so far remain rock stable, you attributed it to sedation. While browsing 5
AM labs you noticed PH of 7.25 and bicarb of 14. Chem-7 showed Cr of 2.1 (baseline 1.1) and K of 5.7. As you get more attentive
to patient, you noticed frequent episodes of bradycardia on monitor. Tracking back monitor in last few hours showed multiple
alarms for bradycardia but went unnoticed as this was the most stable patient in unit. Also pulse ox now trending in lower
90s. You ordered lactate level, cardiac enzymes, EKG, CXR, broad spectrum antibiotics, panculture, adjust ventilator and gave
IVF bolus. Lactate level is back with 7.2 and indeed pt. has NSTE MI with Troponin-I of 7.1. You discuss case with primary
service and now cardiology, nephrology and ID services are on case. Pt continue to deteriorate and died 48 hours later despite
combined endeavors of all services to salvage his hemodynamic collapse.
Your diagnosis: (Choose one)
MI from plasma exchange therapy.
B. Acute septic shock due to use of steroid.
C. Side effect of propofol.
renal failure from hypotension.
E. Ventilator associated pneumonia.Ans is (C): Propofol infusion syndromeAs propofol has gained enormous
popularity in ICUs, it is extremely important to be aware of "Propofol infusion syndrome" when drip is continued for more
than 48 hours with dose above 5mg/kg/hr. Syndrome consist of myocardial failure, metabolic acidosis, renal failure, lipemia,
rhabdomyolysis, and hyperkalemia. Clues to "Propofol infusion sundrome" are unexplained lactate level, bradycardia and increasing
need for pressors. It’s a clinical diagnosis.Due to poorly understood reason,
syndrome is associated with acute neurological illnesses or acute inflammatory diseases and receiving steroids in addition
to propofol. Some critics blame high lipid content of infusion for syndrome.Discussing
A is wrong as acute MI is associated with IVIG theraphy for GBS and unlikely with plasma exchange.
Also, this patient finished his therapy 2 days ago.
B is wrong as there is no clear evidence of sepsis and short term
use of steroid has less likely reason for acute sepsis. But please note that it is very important to practice aseptic technique
while handling propofol.
D is possible but it is unlikely that extreme hypotension will go unnoticed in ICU.
- VAP is not associated with this clinical pictureReference:
Pharmacother. 2002 Sep;36(9):1453-6, The Lancet 2001;357:117-118, Intensive Care Med. 2003 Sep;29(9):1417-25.Bonus Pearl: Propofol infusion is noticed to turn colour of urine
green. It is a benign potential side effect of Propofol. Recognition of this side effect is important as it averts unnecessary
further workup and limits medical expenditures.
Tuesday October 10, 2006
glycol and Ativan drip
Propylene glycol, also known as 1,2-propanediol, is a tasteless,
odorless, and colorless liquid that is use for many drugs with poor aqueous solubility including lorazepoam, diazepam, esmolol,
nitroglycerin, pentobarbital, phenytoin, bactrim and others. Usually it is safe but important to know that it is metabolized into lactic acid and pyruvate.
Being an intensivist
it is imperative to understand the dangers of propylene glycol particularly with Lorazepam drip - particularly if it is continued
beyond 48 hours and dose more than 10 mg/hr. Each 2 mg of lorazepam (one ml) on average contains 0.8 ml of propylene glycol.
Any unexplained high anion gap metabolic acidosis with elevated osmol gap, should prompt the diagnosis of propylene gylcol
Propylene glycol toxicity secondary to high-dose lorazepam infusion should be kept in mind with compromised
renal function but may happen with normal kidney. Although propylene glycol toxicity often resolves after discontinuation
of Ativan but if acidosis continues, hemodialysis said to lowers propylene glycol serum concentrations.
Monday October 09, 2006Gastrointestinal
Complications in Patients Undergoing Heart Operation
An important article published
last year in Annals of Surgery 1 and should be read by intensivists
working particularly in cardiothoracic units (CT-CV-ICU).
8709 Consecutive Cardiac Surgical Patients were analyzed
for gastrointestinal complications. Though GI complications are rare (n = 46 - 0.53%) but need great vigilance of intensivist
as these are life saving if identify early. Intensivist should not get deceived if surgery is off-pump 2 or minimally invasive (MIDCAB) 3.
Preoperative predictors of complication were
- Prior cerebrovascular accident (CVA),
- Chronic obstructive pulmonary disease (COPD),
- Heparin-induced thrombocytopenia (Type II),
- Atrial fibrillation,
- Prior myocardial infarction,
- Renal insufficiency,
- Hypertension, and
- need for intra-aortic balloon counter-pulsation (IABP).
The most frequent serious GI complication were
- Mesenteric ischemia (n = 31/46 or 67% of patients). 22 Twenty-two were explored
and 14 died within 2 days of heart operation. Of the 9 patients with mesenteric ischemia who were not explored, 7 died within
3 days of heart operation.
- Diverticulitis (5/46),
- Pancreatitis (4/46),
- Peptic ulcer disease (4/46), and
- Cholecystitis (2/46).
Predictors of death from GI complication included
- New York Heart Association class III and IV heart failure,
- Chronic obstructive pulmonary disease,
- History of syncope,
- AST more than 600U/L,
- Direct bilirubin more than 2.4mg/dL,
- PH less than 7.30, and
- The need for more than 2 pressors.
Again! The biggest guard is high suspicion
and constant vigilance.
References: click to get abstract or article
Gastrointestinal Complications in Patients Undergoing Heart Operation - Ann Surg. 2005 June; 241(6): 895–904.
Off-pump coronary artery bypass surgery does not reduce gastrointestinal
complications. Eur J Cardiothorac Surg. 2003;23:170 --174
after Minimally Invasive Coronary Artery Bypass Grafting: A Report 2 Cases - The Heart Surgery Forum, Volume 9, Number 5 /
Sunday October 08, 2006
Topics you can't afford to
miss for Critical Care Board exams - Part 3
Since last 2 weeks we are posting important
topics to prepare for our fellows to prepare for Internal Medicine's Critical Care Board exam. Click for Part 1 and Part 2. Here are few more topics.
- Indication of digibind in Dig toxicity
- Management of pulmonary artery rupture (one lung ventilation)
- Atrial fibrillation - Management in stable as well as hemodynamic shock
- Amiodarone induced 'acute' lung toxicity
- Identify pneumothorax in CXR
- Identify central line in arterial system - CXR
- CT scan picture in late stage ARDS
- Calculation / formula of required calorie in ICU patient
- C-diff colitis - identification
- Identification / risk of DVT and PE in ICU patients
- Diagnosis of TTP
- Hepato-toxicity of Quinolones
- Adjustment of Lovenox in renal failure
- Hypophosphatemia in TPN
- Tretment of organophophate poisioning
- Management of acalculous cholycystitis after CABG.
- Not to get deceive by mildly elevated BNP.
- Antibiotic choice in neutropenic fever.
- Need of Iron in Erythropoetin treatment.
- Diagnosis of Abdominal compartment syndrome
Saturday October 07, 2006
For Diameters of needles, catheters, tubes and wires there are 2 essential systems and it is important
to understand the difference between two.
Intensivists perform multiple procedures and use different wires while utilizing Seldinger’s technique
or needles and IV catheters.
A traditional unit measuring the diameter (or the cross-sectional area) is Gauge. Various
wire gauge scales have been used in the U.S. and Britain. The Stubs Iron Wire Gauge system (also known as the Birmingham Wire
Gauge) is used in medicine to measure the diameter of hypodermic needles, intravenous catheters, and suture wires. It was
originally developed in early 19th-century in England for use in wire manufacture, and it began appearing in a medical setting
in the early 20th century. the Gauge system is not truly linear.Needles / IV catheters:
The needle gauge is inversely proportional to its diameter, so the larger the gauge number, narrower the diameter. Click here to see Needle Gauge Chart.
Wires: In traditional
scales (U.S. STANDARD WIRE GAUGE), larger gauge numbers represent thinner wires. (For very thick wires, repeated zeros are
used instead of negative numbers, so gauges 00, 000, and 0000 represent -1, -2, and -3, respectively.) For example, 0000 gauge
represents a wire having a diameter of 0.46 inch and 36 gauge represents a diameter of 0.005 inch. Click here to see the table for U.S. STANDARD WIRE GAUGE.
Joseph-Frederic-Benoit Charriere was a 19th century maker of surgical instruments.
Charriere made significant advances in ether administration, urologic, and other surgical instruments. He has credit of inventing
the modern syringe. But his most significant contribution is to develop a uniform , standard gauge specifically designed for
use in medical equipment such as catheters, drains and probes. Remember ! British system is not linear and confusing as Gauge
# gets bigger, the diameter get smaller. Unlike the British gauge system Charriere's system (or French Gauge) has uniform
increments between gauge sizes ( 1 French = 1/3 of a millimeter) and is easily calculated, linear and predictable like:
French = 1/3 of a millimeter , so
5 French = 1/3 x 5 = 1.66 millimeter
French Gauge sytem is mostly use for
drains and tubes.
Friday October 06, 2006
Q: Why Etomidate may not be a good choice in neurological and
neuro-surgical patients ?
A: It may
decrease the seizure threshold.
Etomidate has fall out of favor in medical ICUs for intubation due to its transient
effect of causing adrenal insufficiency, which makes it undesirable in septic patients. But another less known side effect
is its ability to decrease the threshold for seizure.
Despite its effect on above 2 groups of patients, it is still
a very valuable drug to use during intubation (atleast in other patients) due to its quality of having minimal effect on hemodynamic
changes, faster effect (15 sec) and quick recovery (3-7 mins). Adrenocortical suppression after single dose is transient which
last for 12-36 hours.
See nice review article : Should We Use Etomidate as an Induction Agent for Endotracheal Intubation in Patients WithSeptic
Shock? - A Critical Appraisal from Dr. William L. Jackson, Critical Care Medicine Service, Department
of Surgery, Walter Reed Army Medical Center, Washington, DC. (Chest. 2005;127:1031-1038.)
Thursday October 05, 2006
Electrical Impedance Tomography
Editors' note: We try to keep our visitors to be posted with new developing
technologies applicable in ICU. The following technology is very interesting, portable at bedside and basically an another
enhanced way of looking at structural as well as functional anatomy of desired organ - along with CT, MRI, EEG, echocardiogram,
Electrical Impedance Tomography (EIT), is a medical imaging technique in which an image of
the conductivity or permitivity of part of the body is inferred from surface electrical measurements. Although investigations
with CT have taught us that ALI and ARDS are heterogeneous diseases and provide important information about alveolar collapse
and reversal of atelactasis, it cannot be applied roultinly in ICU with ALI / ARDS patients.
EIT can produce images
by placing electrodes around the anatomy of interest and studying the preferential paths of current flow. Computer reconstruction
techniques are employed to generate images, which although of poor resolution, can give functional information in real time.
EIT measures the distribution of impedance in a cross-section of the body. This is possible because the electrical resistivities
of different body tissues varies widely from 0.65 ohm m for cerebrospinal fluid to 150 ohm m for bone.
can be recorded a series of electrodes are attached to a subject in a transverse plane. These are linked to a data acquisition
unit, which outputs data to a PC. By applying a series of small currents to the body a set of potential difference measurements
can be made from non-current carrying pairs of electrodes. Since electric currents applied to the body take the paths of least
impedance, where the currents flow depends on the subject's conductivity distribution. For example, the heart is full of blood.
Blood conducts electricity well, so the heart has a low impedance. The lungs are filled with air. Air does not conduct electricity
well, so the lungs have relatively high impedance. Therefore images can be reconstructed from the data using a variety a methods.
Proposed applications include monitoring of lung function, detection of cancer in the skin and
breast and location of epileptic foci.
All applications are currently considered experimental.
Wednesday October 04, 2006Q; You have admitted a patient with thyroid storm. You wrote all orders including
IVF, tylenol (aspirin is relatively contraindicated for control of pyrexia in thyroid
storm), propranolol, hydrocortisone, propyl thiouracil (PTU)and order for oral potassium iodide one hour after
administration of PTU (Yes ! you have to wait one hour to give iodide after PTU
or Methimazole) . You received call from pharmacy that patient has documented allergy to iodine in previous
medical record. What's your next option instead of iodine ?A;
In patients allergic to iodine, you may use lithium carbonate to reduce secretion of pre-formed
thyroid hormone. Start dose with 300 mg PO every 6 hours and follow level closely to keep at 1 meq/L.
Tuesday October 03, 2006
of hypokalemia in hypothermiaHypothermia commonly causes hypokalemia but should
be treated very cautiously and gently. As patient has been re-warmed, potassium exits cells and may cause deadly hyperkalemia. 1, 2 This is not a pseudo-hypokalemia but a phenomenon of electrolyte movement
across cell membrane induced by whole body temperature change. There should be a written protocol for gentle correction and
followup of potassium during hypothermia and hyperthermia phase.Bonus Pearl:
is usually seen with very high WBC count, when the drawn sample is allowed to sit at room temperature for longer period of
time. It happens due to uptake of plasma potassium by high leukocytes in the sample. If Pseudo-hypokalemia is suspected, real
potassium level can be measured by sending specimen quickly (preferably taking manually to lab as soon as drawn) and requesting
to measure potassium level in separated plasma or serum.Related previous
Pearl: The TransTubular Potassium Gradient - TTKGReferences: click to get articles/abstracts
Hypothermia-induced hypokalemia Mil Med.1998 Oct;163(10):719-21.
2. Serum potassium levels during prolonged hypothermia, Intensive Care Medicine Volume 9, Number 5 / September, 1983,
Monday October 02, 2006
Pulmonary impairment in diabetes mellitus is under-recognized. The alveolar-capillary
network receives the entire cardiac output and constitutes the largest microvascular organ in the body, making it highly susceptible
to systemic microangiopathy. Owing to its large reserves, symptoms and disability develop later in the lung than in smaller
microvasculature such as the kidney or retina despite a comparable severity of anatomic involvement.
It is not a new
concept and numbers of classic studies are available. We just choose to ignore it !
* Investigators from the Copenhagen City Heart Study enrolled nearly 12,000 subjects ages 20 and older. Among
them were 284 with clinician-diagnosed diabetes and 177 with abnormal glucose tolerance. On average, patients with diabetes
had lower lung function values and a more rapid rate of decline than those without diabetes. At the five-year follow up lung
function loss among diabetes patients exceeded that of the non-diabetes cohort by 29 ml (FVC) and 25 ml (FEV1) per year, a rate of decline comparable to that of smokers.
(Lange P, Groth S, Montensen J, et al. Diabetes mellitus
and ventilatory capacity: a five year follow-up study, Eur Respir J. 1990;3:288-292)
* The Fremantle Diabetes Study from Australia plotted lung function values from 125 non-smokers
with type II diabetes and no pre-existing lung disease over a seven-year period. During this time, the
rate of lung function decline was about twice that expected (mean decrease, 68 ml/year for FVC and 71 ml/year for FEV1)
(Davis WA, Knuiman M, Kendall P, et al. Glycemic exposure is associated with reduced pulmonary function
in type 2 diabetes: the Fremantle Study. Diabetes Care. 2004;27:752-757)
Other recommended readings: click to get articles
Lung Function and Glucose Metabolism: An Analysis of Data from the
Third National Health and Nutrition Examination Survey - Am. J. Epidemiol. 2005;161:546-556.
2. Lung Dysfunction in Diabetes Goldman, Diabetes Care 2003;26:1915-1918.
Sunday October 01, 2006
you can't afford to miss for Critical Care Board exams - Part 2
week we posted few important topics (click here to see) for our fellows for upcoming Internal Medicine's Critical Care board exam (November
8, 2006) . Here are few more topics you can't afford to miss for Critical Care Board exams.
- Management of acute cirrhotic / variceal GI bleed
- End of life issues / ethic questions - list of power of attorneys in order
- Antibiotic choices in necrotising fascitis.
- Hepato-renal syndrome
- Vancomycin dosing in CVVHD
- Baterial menigitis CSF findings and treatment
- VAP - diagnosis and treatment
- Thrombolytics and surgical indications in PE
- EKG findings in Acute MI and pericarditis
- EKG findings in hyperkalemia
- Clinical scenario and acute management of venous air embolism
- Treatments of hypothermia (all time board's favourite)
- Hypokalemia in hypothermia
- Asystole in hypothermia - approach to treatment
- Indication of dialysis in lithium overdose
- Cholesterol emboli - diagnosis
- Contrast induced nephropathy - preventions
- Arterial line - underdamp and overdamp picture
- Green urine after propofol drip
- QT interval prolongation with haldol.