Friday July 31, 2009 (pediatric pearl)
Uniqueness of Pediatric Lower Airway


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 respiratory pump includes the nervous system with central control (ie, cerebrum, brainstem, spinal cord, peripheral nerves), respiratory muscles, and chest wall. Features of note in pediatric patients include the following:

• The respiratory center is immature in infants and young children and leads to irregular respirations and an increased risk of apnea.
• The ribs are horizontally oriented. During inspiration, a decreased volume is displaced, and the capacity to increase tidal volume is limited compared with that in older individuals.
• The small surface area for the interaction between the diaphragm and thorax limits displacing volume in the vertical direction.
• The musculature is not fully developed. The slow-twitch fatigue-resistant muscle fibers in the infant are underdeveloped.
• The soft compliant chest wall provides little opposition to the deflating tendency of the lungs. This leads to a lower functional residual capacity in pediatric patients than in adults, a volume that approaches the pediatric alveolus critical closing volume.

Thursday July 30, 2009
Application of bundle does make difference!

VAP bundle * impact in an intermediate respiratory care unit

Introduction: Ventilator-associated pneumonia (VAP) is the most frequent ICU-related infection in patients requiring mechanical ventilation, who have a mortality rate ranging from 20% to 50%, prolonging the duration of mechanical ventilation and the ICU length of stay, and increasing costs. We describe the impact of VAP bundle use in an intermediate respiratory care unit (IRCU) to prevent VAP in patients requiring prolonged ventilation.

Methods: A prospective observational study enrolled all tracheotomized patients admitted to a seven-bed IRCU of a tertiary care hospital between March 2005 and October 2007. The daily VAP bundle checklist as described by the Institute for Healthcare Improvement was performed since March 2006 to evaluate compliance. VAP diagnosis was supported by the Clinical Pulmonary Index Score and microbiological quantitative criteria. The mean duration of mechanical ventilation and VAP rate per 1,000 ventilator-days pre and post the bundle period was evaluated and compared using the likelihood ratio for VAP from a Poisson distribution. P < 0.05 was considered significant.

Results: Eighty-eight patients were studied, 40 females and 48 males. The mean age and APACHE II score were 76 ± 12 years and 14 ± 5, respectively. We analyzed 3,727 records during the study period. There were a total of 53 VAP episodes. The compliance rate was 97%. The mean duration of mechanical ventilation pre and post bundle was similar (17.8 and 17.78 days, respectively).

The VAP rate decreased from 22 cases per 1,000 ventilator-days to 9.76 cases per 1,000 ventilator-days: a 55.78% reduction at the end of 20 months of bundle use (P value less than 0.05).

Conclusion: The application of the VAP bundle in chronic ventilated patients resulted in a significant reduction in the incidence of VAP.


* Note: The key components of the Ventilator Bundle are:

Elevation of the Head of the Bed
Daily "Sedation Vacations" and Assessment of Readiness to Extubate
Peptic Ulcer Disease Prophylaxis
Deep Venous Thrombosis Prophylaxis



Reference: Click to get abstract

Ventilator-associated pneumonia bundle impact in an intermediate respiratory care unit from 28th International Symposium on Intensive Care and Emergency Medicine, Brussels, Belgium. 18–21 March 2008, Critical Care 2008, 12(Suppl 2):P433

Wednesday July 29, 2009


Case: 34 year old female with history of recurrent DVT now on chronic Coumadin therapy, presented with black tarry stool and probable GI bleed. There was on change on her usual coumadin dose of 5 mg/day on which she had therapeutic INR of 2.8 since last 2 years. Today her INR is 7.8. One week ago, she has a bout of severe UTI (urinary tract infection) and started on antibiotics by her primary care physician?




Answer: Quinolone (Ciprofloxacin/levofloxacin) - Coumadin interaction

Coumadin-Quinolone are among top ten drug-drug interactions. The exact mechanism for the warfarin-quinolone drug interaction is unknown. Reduction of intestinal flora responsible for vitamin K production by antibiotics is probable as well as decreased metabolism and clearance of warfarin. It can notoriously increase effects of warfarin, with potential for life threatening bleeding.

Best approach is to avoid quinolone in Coumadin dependent patient but if required, INR should be monitored daily during co-administration of warfarin with a quinolone.

Tuesday July 28, 2009
Bedside tip

Case: After uneventful insertion of IABP (intra-aortic balloon pump) - you have been informed that, it will take a while before CXR can confirm proper location of tip of IABP. What is one easy method to determine that you have not 'over-shooted' the tip of IABP?


Answer: Check the left radial pulse

Ideally, the tip of the balloon should be positioned 2–3 cm distal to the origin of the left subclavian artery (LSCA). This position results in maximum augmentation of coronary artery flow although minimizing the risk of embolization to the cerebral vessels and occlusion of the LSCA. If you have good left radial artery pulsation, probably your tip of IABP is distal to LSCA.


Related previous pearl: Carina as a Radiographic Landmark for Positioning the IABP

Monday July 27, 2009
Thoracic ultrasound for pneumothorax

Sunday July 26, 2009

Case: 42 year old female presented with worst headache of her life. Following CT scan obtained. Your diagnosis (Hint: Watch Red marked area) ?

Answer: Subarachnoid hemorrhage (SAH)

Subarachnoid hemorrhage (SAH) is the presence of blood within the subarachnoid space from some pathologic process, usually from rupture of a berry aneurysm or arteriovenous malformation (AVM).

Saturday July 25, 2009

Q; What is the approximate half life of infusing epinephrine in septic shock patient?


Answer: About 3.5 minutes

Also, note that - Epinephrine pharmacokinetics is linear in septic shock patients, without any saturation at high doses. Basal neurohormonal status does not influence epinephrine pharmacokinetics.



Reference: Click to get abstract

Pharmacokinetics of epinephrine in patients with septic shock: modelization and interaction with endogenous neurohormonal status - Published july 21, 2009 - Critical Care 2009, 13:R120

Friday July 24, 2009 (pediatric pearl)
Kidney Blood Supply

Even though the kidney receives 25% of the cardiac output only 2% supplies the renal medulla. It is important so as to have sluggish flow and to be able to maintain high osmolarity in the interstitium for counter-current mechanism. However it predisposes the medulla to ischemia when there is arteriopathy (diabetes mellitus); abnormal blood cells (sickle cell disease); or with chronic use of analgesics (which impairs intra-renal auto-regulation and causes vasoconstriction). This can result in loss of concentrating capacity of the urine and causes the patient to have a fixed specific gravity (1.007 to 1.010).

Thursday July 23, 2009
Ambien Induced Delirium

Relatively Zolpidem (Ambien) is a safe medicine and recently has been one of a drug of choice in critical care units to induce sleep. But it is important to be aware of reported cases of ambien related psychosis, delirium and mania. Atleast one case is reported with visual perception distortion after a single dose of zolpidem.One way to combat the problem is to decrease the prescribing dose particularly in elderly population and in hypoalbuminemia (5 mg instead of 10 mg). Also, female population has been reported to have more plasma level with same dose. Also note that Zolpidem metabolized through liver so it may be necessary to decrease the dose in liver insufficiency.


References: click to get abstract/article

1. Delirium associated with zolpidem - The Annals of Pharmacotherapy: Vol. 35, No. 12, pp. 1562-1564

2. Zolpidem-Induced Delirium With Mania in an Elderly Woman - Psychosomatics 45:88-89, February 2004

3. Zolpidem-induced agitation and disorganization. - Gen Hosp Psychiatry. 1996 Nov;18(6):452-3. (pubmed)

4. Zolpidem-induced psychosis. - Ann Clin Psychiatry.1996 Jun;8(2):89-91. (pubmed)

5. Clinical pharmacokinetics of zolpidem in various physiological and pathological conditions, in Imidazopyridines in Sleep Disorders. Edited by Sauvanet JP, Langer SZ, Morselli PL. New York, Raven Press, 1988, pp 155–163

6. Zolpidem-Induced Distortion in Visual Perception - The Annals of Pharmacotherapy: Vol. 37, No. 5, pp. 683-686

Wednesday July 22, 2009

Scenario: You have a patient with acute exacerbation of asthma. Pharmacy informed you that only steroid available is hydrocortisone. What is the dose of hydrocortisone in acute exacerbation of asthma?



Answer: Hydrocortisone (Cortef) 100 to 250 mg IV q 6 hours


Following are different steroids can be use in exacerbation of asthma

Betamethasone (Celestone) 0.5 to 0.9 mg IM/PO qd
Cortisone (Cortone) 25-300 mg PO qd
Dexamethasone (Decadron) 0.75-9 mg PO/IM/IV q q6h

Hydrocortisone (Cortef)
Parenteral: 100 to 150 mg IV/IM q2-6 hours prn
Oral: 20 to 240 mg/day PO in divided dosing

Methylprednisolone
Parenteral (Solu-Medrol) 10 to 125 mg IV/IM q 6
Oral (Medrol) 4 to 48 mg PO qd

Tuesday July 21, 2009

Interesting Echo
Cardiac Tamponade with clot after Trauma

Monday July 20, 2009
Standardization of quality assurance for sleep technologist: a model
Salim Surani & Raymond Aguillar & Roy Aguillar & Shyam Subramanian

Introduction: Since the last decade, there has been a tremendous growth of sleep centers in the US to meet the increasing need of diagnosing and treating sleep disorders. However, this unregulated growth has resulted in tremendous variance in the quality of sleep centers across the nation. The American Academy of Sleep Medicine, in an attempt to provide a benchmark standard, has introduced a voluntary accreditation process, part of which involves assessment of technical quality parameters. However, measuring technical quality is not easy.

Hypothesis: We undertook a study to determine if the implementation of point system and schematic feedback on technologist performance can result in improvement and tracking of their performance.

Materials and methods: We randomly reviewed 100 charts from the preimplementation phase as control and 1,739 charts from the post implementation of the point system phase as study group.

Results: There was a statistically significant difference in the score among technologist between the control and study groups with the average being 75±4.12 and 87.53±0.91, respectively, with a p value being 0.0001.

Conclusion: Evaluating the performance of the sleep technologist can be a way to track and monitor their performance in a standardized way and to identify weakness at an earlier stage. We present a system, which we have developed and implemented at our sleep center, as a possible model of assessing and subsequently standardizing technical quality for polysomnography.

- Dr. Surani is also co-editor of this website

Reference: Click to get abstract

Surani S, Aguillar R, Aguillar R, Subramanian S - Standardization of quality assurance for sleep technologist: a model. - Sleep Breath 2009 Jun 30.

Sunday July 19, 2009
ARDS - A Clinicopathological Confrontation

Very important read to understand why we get burn so much from ARDS!

Background: The heterogeneity of populations meeting criteria for ARDS may explain in part why no specific treatment has yet been shown to decrease mortality. To define the pathologic alterations associated with the syndrome, particularly the typical pattern of diffuse alveolar damage (DAD), and to evaluate whether etiologies or precipitating factors were missed, we evaluated patients who died with a clinical diagnosis of ARDS and who had a postmortem examination.

Methods: We conducted a 3-year (2002 to 2004) review of all patients with ARDS (using the American-European Consensus Conference criteria) who died in our ICU and had a postmortem examination. Discrepancies between antemortem and postmortem diagnoses were classified as major and minor using the Goldman classification.

Results: Of 9,184 hospital admissions, 376 patients had a clinical diagnosis of ARDS. Of these, 169 died; 69 had a postmortem examination, and 64 of these had complete data for analysis.

• The main cause of death was multiple organ failure (27 of 64 patients).
• Postmortem examination revealed DAD in 32 patients (50%),
• pneumonia without DAD in 16 patients (25%), and invasive pulmonary aspergillosis in 8 patients (12.5%).
• Major unexpected findings were found in 15 patients (23%): 7 Goldman class I (including 4 cases of invasive pulmonary aspergillosis and 1 of disseminated tuberculosis) and 8 Goldman class II.

Conclusions: In this study, ARDS remains a heterogeneous syndrome because only half of patients with ARDS had typical DAD. Open lung biopsy, if performed, might have led to appropriate therapy and potentially better outcome in five of the patients.


Reference: Click to get abstract

ARDS- A Clinicopathological Confrontation- CHEST April 2009 vol. 135 no. 4 944-949

Saturday July 18, 2009

Aortic Dissection

Friday July 17, 2009 (pediatric pearl)
Patent Ductus Arteriosus (PDA)

Only 3% of PDA’s are patent by 3 days in TERM neonates (unlike pre-term neonates). Therefore if after this period the ductus arteriousus is still patient it is unlikely to close spontaneously.

Wednesday July 15, 2009

Case: You are performing 'code blue' on a patient. You do not have an arterial line. What would be the best way to determine the efficacy of resuscitation?


Answer: Venous Blood Gas (VBG)

Arterial blood gas (ABG) analysis is useful in evaluation of the clinical condition of critically ill patients; however, arterial puncture or insertion of an arterial catheter may not be feasible or available in many situations. The VBG is easier, quicker, and safer to obtain and is associated with significantly less pain for the patient. It would be convenient for physician and patient to be able to replace the ABG with the VBG for analysis of base excess(acidosis). Actually, in code situation VBG would be a better indicator of overall acidosis. If VBG results are normal, ABG analysis should not be necessary. Conversely, abnormal venous levels predicted abnormal arterial values. A venous pH of 7 or lower, for example, predicted an arterial pH of 7.2 or lower.

In cardiac arrest victims, the disparity between arterial and venous values is even greater. During cardiac arrest, tissue hypoxia is all but a certainty and is reflected by the lower pH and higher PCO2 on the venous side.

Tuesday July 14, 2009
Milrinone for coronary vasospasm?

A 42-year-old male presented to the emergency department with acute chest pain. The electrocardiogram revealed inferior wall myocardial infarction. Emergency coronary angiography revealed total occlusion of the distal right coronary artery with thrombus. Patient was taken up for primary percutaneous coronary angioplasty with stenting of distal right coronary artery. Six hours following the procedure, the patient developed re-elevation of ST-segment in inferior leads of electrocardiogram and subsequent haemodynamic instability. Repeat coronary angiography revealed patent stent and coronary artery spasm in proximal part, which was relieved by intracoronary injection of nitroglycerine. After an hour, the patient re-developed symptoms of chest pain along with bradycardia, hypotension and ST segment elevation. Intravenous infusion of nitroglycerine did not improve the condition but produced persistent hypotension. Infusion of milrinone was then started. Over time, normalisation of electrocardiogram occurred. The patient was discharged in stable condition. This case suggests that milrinone may be effective in alleviating coronary artery spasm when the use of other agents fails.



Reference: click to get abstract

Milrinone infusion: A therapeutic option in coronary vasospasm after primary percutaneous transluminal coronary angioplasty - Case Report Year : 2009 Volume : 12 Issue : 1 Page : 67-70

Monday July 13, 2009

Case: 32 year old female presented with acute left sided shoulder pain and swelling. Hint: see picture below?






Answer: Thoracic Outlet Syndrome (TOS)

In general, TOS occurs in young people. There are 3 kinds of TOS

Neurogenic TOS (80%): an injury probably causes tearing and spasm in the scalene muscles, which become inflamed and scarred, irritating the adjacent nerves.

Arterial TOS (5%): the patient has developed an aneurysm of the subclavian artery in the neck; clots may break off and travel to the hand, which turns painful and numb.

Venous TOS (15%) — sometimes called “effort thrombosis” — begins when the subclavian vein is pinched between the rib and collarbone, which leads to a vein injury. With repeated injuries, a cuff of scar tissue forms, narrowing the vein; pressure builds up behind it, and the body forms collateral vessels to handle the blood flow. But the obstructed vein still has some stagnant blood flow, prone to forming a clot; if this clot propagates, blocking the collaterals, the arm suddenly swells.

Surgery is mostly required.

Sunday July 12, 2009
Picture Diagnosis - What is your diagnosis?

Answer: Giant Bullous Emphysema

Above chest x-ray showing a giant bulla occupying more than two thirds of the right hemithorax and compressing the underlying lung upward and towards the mediastinum. This can be misdiagnosed as pneumothorax.

Saturday July 11, 2009


Q: Does Phenytoin (Dilantin) get cleared by hemodialysis or hemoperfusion?


A; No (clinically insignificant removal)

Clinical significance:

1. In Phenytoin toxicity, Hemodialysis or hemoperfusion are ineffective for enhancing elimination.

2. Hemodialysis patients do not require extra dosing post dialysis though require frequent monitoring due to lower albumin level.

Friday July 10, 2009

Q: In which of the following conditions mixed venous oxygen saturation (SvO2) could be more than 80%?

• Sepsis
• Cirrhosis
• VSD (Ventricular septal defect)
• Cyanide poisoning
• All of the above
  
  

Answer: All of the above conditions may give higher than normal value for mixed venous oxygen saturation (SVO2).

Thursday July 9, 2009

Q: Tachyphylaxis to IV nitroglycerin drip develop in how many hours?

Answer: Tachyphylaxis to IV nitroglycerin develop approx. in about 16-24 hours.



References: Click to get abstract

1. Comparison of the degree of hemodynamic tolerance during intravenous infusion of nitroglycerin versus nicorandil in patients with congestive heart failure - Clinical Investigations - American Heart Journal. 134(3):435-441, September 1997.

Wednesday July 8, 2009

Q: Which very commonly use resuscitation fluid in ICU may cause pesudo-hyperamylasemia?


Answer: Hetastarch

The infusion of hydroxyethyl-starch leads to hyperamylasemia due to the complex structural interrelation of the amylase molecules in the serum and the hydroxyethyl-starch molecules. The amylase clearance is reduced because glomerular filtration of the macromolecules thus formed is not possible. It takes about a week for a level to return to normal after hetastarch infusion.

Workup for presumed pancreatitis may be expensive and futile.



References: Click to get abstract

1. Gofferje H, Kozlik V. [Hyperamylasemia following infusion of hydroxyethyl starch with different molecular weight distributions - Infusionsther Klin Ernahr. 1977 Jun;4(3):141-4

2. Treib J, Baron JF, Grauer-MT, Strauss-RG. An international view of hydroxyethyl starches. Intensive Care Med 1999;25:258–68.

Tuesday July 7, 2009
Assessment of Left Ventricular Function by Intensivists Using Hand-Held Echocardiography

Background: Bedside transthoracic echocardiography (TTE) provides rapid and noninvasive hemodynamic assessment of critically ill patients but is limited by the immediate availability of experienced sonographers and cardiologists.

Methods: Forty-four patients in the medical ICU underwent near-simultaneous limited TTE performed by intensivists with minimal training in echocardiography, and a formal TTE that was performed by certified sonographers and was interpreted by experienced echocardiographers. Intensivists, blinded to the patient's diagnosis and the results of the formal TTE, were asked to determine whether left ventricular (LV) function was grossly normal or abnormal and to place LV function into one of the following three categories:

• normal
• mildly to moderately decreased; and
• severely decreased
  

Results:

• Using the formal TTE as the “gold standard,” intensivists correctly identified normal LV function in 22 of 24 cases (92%) and abnormal LV function in 16 of 20 cases (80%).
• Intensivists correctly placed LV function into one of three categories in 36 of 44 cases (82%); in 6 of the 8 cases that were misclassified, the error involved an overestimation of LV function.

Conclusions: Intensivists were able to estimate LV function with reasonable accuracy using a hand-held unit in the ICU, despite having undergone minimal training in image acquisition and interpretation.

icuroom editors' note: All intensivists should be encouraged to seek minimal training in bedside echocardiography.



Reference: Click to get abstract

Assessment of Left Ventricular Function by Intensivists Using Hand-Held Echocardiography - CHEST June 2009 vol. 135 no. 6 1416-1420

Monday July 6, 2009

Q: Rewarming after therapeutic hypothermia should begun 24 hours after the

A) time of initiation of cooling or
B) from the time the target temperature (32-34 C) is achieved.

(Choose one)



Answer: Countdown for rewarming after therapeutic hypothermia should begun 24 hours after the time of initiation of cooling. The patient should be actively cooled by using an induced hypothermia protocol for 24 hours to a goal temperature of 32-34ºC. The goal is to achieve the target temperature as quickly as possible. In most cases, this can be achieved within 3-4 hours of initiating cooling.

See very good review article on Therapeutic Hypothermia (emedicine.com)

Sunday July 5, 2009
O2 Delivery & O2 Consumption curve in acute bleeding

Saturday July 4, 2009
Emergency Echocardiography

Friday July 3, 2009 (pediatric pearl)
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.

Thursday July 2, 2009


Q: One unit of platelet transfusion expect to increase platelet count by how much ?

Answer; Each unit of platelet transfusion is expected to increase platelet count by 7 - 10,000 / uL. Platelet transfusion is usually given as 6 or 10 units together.

Wednesday July 1, 2009
Picture Diagnosis

Case: A 35-year-old man underwent pericardiectomy for pericarditis. Post procedure CXR and CT scan film is below, which shows a huge mass abutting the mediastinum in the left upper lung zone. Note: Pre-procedure CXR was normal and had no such mass!!

Answer: Gossypiboma

Gossypiboma is a technical term for retained surgical sponge. Patient underwent left upper lobectomy, and pathologic examination revealed gossypiboma (retained surgical sponge).