Thursday, December 31, 2009
Case: Define chylothorax and describe different treatment modalities?
Answer: Chylothorax is defined as triglycerides more than 113 mg/dl (1.24 mmol/L) in pleural cavity.
A number of therapeutic interventions have been used to reduce chyle production and promote resolution of a chylothorax. Initial management typically includes restriction or temporary cessation of enteral feedings. Enteral feedings high in medium-chain triglycerides (MCT), or parenteral nutrition may be used. Total parenteral nutrition typically results in resolution in 75 to 80% of cases by that time. In resistant cases, pleurodesis, ligation of the thoracic duct, or placement of drains and pleuroperitoneal shunts may be considered.
Octreotide has become another option for management of patients with chylothorax. Although the exact mechanism by which the drug exerts its effects has not been defined, it is believed that the multiple effects of octreotide on the gastrointestinal tract and the reduction in splanchnic blood flow reduce thoracic duct flow and decrease the triglyceride content of chyle.
Wednesday, December 30, 2009
Wednesday December 30, 2009
Case: 38 year male presented to ER with severe chest pain. Patient informed you that he carries the diagnosis of Loeys-Dietz syndrome. What is your concern?
Answer: Aortic aneurysm rupture
Loeys-Dietz syndrome is an autosomal dominant genetic syndrome which has many features similar to Marfan syndrome, which is caused by mutations in the genes encoding transforming growth factor beta receptor 1 (TGFBR1) or 2 (TGFBR2). The disorder was first observed and described by Dr. Bart Loeys and Dr. Hal Dietz at the Johns Hopkins University School of Medicine in 2005.
Many of the physical findings typical in Loeys-Dietz syndrome are also found in Marfan syndrome cases, including increased risk of ascending aortic aneurysm and aortic dissection, abnormally long limbs and fingers, and dural ectasia (a gradual stretching and weakening of the dura mater that can cause abdominal and leg pain). However, it also has some additional traits not typical of Marfan patients, including widely spaced eyes, a split uvula in the back of the throat, and skin findings such as easy bruising or abnormal scars.
Bonus Pearl: Animal research has suggested that the angiotensin II receptor antagonist losartan, which appears to block TGF-beta activity, can slow or halt the formation of aortic aneurysms in Marfan syndrome 1. A large clinical trial sponsored by the National Institutes of Health is currently underway to explore the use of losartan to prevent aneurysms in Marfan syndrome patients. Both Marfan syndrome and Loeys-Dietz syndrome are associated with increased TGF-beta signaling in the vessel wall. Therefore, losartan also holds promise for the treatment of Loeys-Dietz syndrome.
1. Losartan in Marfan's syndrome - Clinicaltrial. gov
Tuesday, December 29, 2009
Association Between ICU Admission During Morning Rounds and Mortality
Background: No previous study has evaluated the association between admission to ICUs during round time and patient outcome. The objective of this study was to determine the association between round-time ICU admission and patient outcome.
Methods: This retrospective study included 49,844 patients admitted from October 1994 to December 2007 to four ICUs (two surgical, one medical, and one multispecialty) of an academic medical center. Of these patients, 3,580 were admitted to the ICU during round time (8:00 am to 10:59 am) and 46,264 were admitted during nonround time (from 1:00 pm to 6:00 am). The medical ICU had 24-h/7-day per week intensivist coverage during the last 2 years of the study. We compared the baseline characteristics and outcome of patients admitted to the ICU between the two groups. Data were abstracted from the acute physiology and chronic health evaluation (APACHE) III database.
Results: The round-time and non–round-groups were similar in gender, ethnicity, and age.
- The predicted hospital mortality rate of the round time group was higher (17.4% vs 12.3% predicted, respectively).
- The hospital length of stay was similar between the two groups.
- The round-time group had a higher hospital mortality rate (16.2% vs 8.8%, respectively).
- Most of the round-time ICU admissions and deaths occurred in the medical ICU.
- Round-time admission was an independent risk factor for hospital death (odds ratio, 1.321; 95% CI, 1.178 to 1.481). This independent association was present for the whole study period except for the last 2 years.
Conclusions: Patients admitted to the ICU during morning rounds have higher severity of illness and mortality rates.
Association Between ICU Admission During Morning Rounds and Mortality - CHEST December 2009 vol. 136 no. 6 1489-1495
Monday, December 28, 2009
Tips on use of Atropine in AV conduction block
Atropine is useful in treating second-degree heart block Mobitz Type 1 (Wenckebach block), and also third-degree heart block with a high Purkinje or AV-nodal escape rhythm.
- It is usually not effective in second-degree heart block Mobitz type 2, and in third-degree heart block with a low Purkinje or ventricular escape rhythm.
- Atropine is contraindicated in ischemia-induced conduction block, because the drug increases oxygen demand of the AV nodal tissue, thereby aggravating ischemia and the resulting heart block.
Sunday, December 27, 2009
Dabigatran is an anticoagulant from the class of the direct thrombin inhibitors. It is being studied for various clinical indications and may replace warfarin as the preferred anticoagulant in many cases. Unlike warfarin it works right away and does not require INR monitoring.
Phase 3 clinical trials are ongoing in treatment and prevention of secondary venous thromboembolism (VTE) in post-operative orthopedic patients; long-term prophylaxis in acute coronary syndrome and stroke patients with atrial fibrillation and symptomatic VTE because of various causes. Dabigatran at doses of 150 mg and 220 mg once daily when compared with the standard 40 mg dose of enoxaparin once daily, confirmed that dabigatran performed as well as enoxaparin in preventing thrombosis, with a similar risk profile.
Absorption is unrelated to food but may be decreased if taken with a proton pump inhibitor. Metabolism is slowed in people taking quinidine, verapamil, or amiodarone.
Approval from FDA is expected in 2010.
Saturday, December 26, 2009
Saturday December 26, 2009
About Tolvaptan (Samsca)
Tolvaptan (Samsca) is the first oral dosage form in a class known as “selective vasopressin antagonists.” These drugs, also referred to as “vaptans,” cause renal elimination of water without increasing urinary excretion of sodium or potassium. An injectable vaptan, conivaptan (Vaprisol), has been available in the U.S. since 2006. Both conivaptan and tolvaptan are indicated for the treatment of hyponatremia. In addition, tolvaptan has been studied for treating heart failure.
Once-daily Samsca has been shown to significantly raise serum sodium concentrations in as early as 8 hours, and the change was maintained for 30 days. Exposure and response to Samsca are similar in patients with a creatinine clearance of 10-79 mL/min and in patients without renal impairment; thus no dosage adjustment is necessary.
The unique mechanism of action of Samsca selectively blocks the binding of vasopressin to the V2-receptors in the collecting duct of the kidney. If the V2-receptors are left unblocked, the binding of vasopressin with these receptors can cause water retention resulting in hyponatremia. By inhibiting the effects of vasopressin at the V2-receptor, Samsca increases the excretion of free water, while the excretion of sodium and other electrolytes is not directly affected (aquaresis).
Friday, December 25, 2009
Thursday, December 24, 2009
Q: What is the rule of thumb to select size of IABP (Intra Aortic Ballon Pump)?
Answer: The size of the balloon is dependent on the patients height to prevent occlusion of sub-clavian or renal arteries.
Less than 160 cm use 34 cc
Between 160 – 182 cm use 40 cc
More than 182 cm use 50 cc
Wednesday, December 23, 2009
Esophageal Perforation Associated With Noninvasive Ventilation - An interesting Case Report
"A 56-year-old man was admitted to our ICU after extensive nephrectomy with partial inferior vena cava resection for renal adenocarcinoma. He had a history of type 2 diabetes mellitus, and the cancer had been diagnosed on evaluation of recent-onset severe arterial hypertension.
The patient was extubated on the day of surgery. No respiratory, circulatory, or infectious complications occurred, but renal failure developed gradually, the suspected cause being intraoperative hypotension. No nausea or vomiting was noted. NIPPV was started via a facemask on day 4 because this morbidly obese patient (122 kg) could not be weaned from nasal oxygen and had persistent moderate hypoxemia with persistent basal atelectasis on the chest radiograph. NIPPV was initiated with a fraction of inspired oxygen of 0.5, a positive end-expiratory pressure of 5 cm H2O, and a pressure-support level of 15 cm H2O. When NIPPV was stopped after 1 h, the hypoxemia worsened, and marked tachypnea with agitation developed. NIPPV was immediately restarted and the pulse oximetric saturation dropped to 97%. After an additional 2 h of NIPPV, hypotension and loss of consciousness occurred, requiring orotracheal intubation, mechanical ventilation, and vasoactive drug therapy. The postintubation chest radiograph disclosed left-sided hydropneumothorax, which was confirmed by CT. A chest tube was inserted, and 1,000 mL of gastric-like fluid was recovered. A left thoracotomy was performed, and a 3-cm linear tear was seen in the lower esophagus. The tear was sutured, drains were placed in the pleural cavity and mediastinum, and a discharge gastrostomy was performed with a jejunostomy for enteral nutrition.
After a transient improvement in the hemodynamic status, multiple organ failure developed. There was no definitive evidence of infection. The patient died 12 days after the thoracotomy".
Esophageal Perforation Associated With Noninvasive Ventilation - A Case Report, CHEST November 2002 vol. 122 no. 5, 1857-1858
Tuesday, December 22, 2009
Q: Define Hemothorax?
Answer: Even a very small quantity of blood can make pleural fluid apppears bloody but a hemothorax is the presence of blood in the pleural cavity such that the ratio of pleural fluid hematocrit to blood hematocrit is more than 0.5.
Monday, December 21, 2009
2 CD VIP
In response to our yesterday pearl "WEANS NOW" we received following pearl from
MABULMAGD , MD, EDIC
Lecturer of critical care medicine, Cairo university
Consultant intensivist, Dar Alfouad Hospital
I found this mnemonics helpful for intensivist during daily clinical rounds (2 CDF VIP)
2P…dvt prophylaxis-ulcer prophylaxis
Sunday, December 20, 2009
Famous "WEANS NOW" of Ventilator Weaning
W: weaning parameter - measure
E: endotracheal tube (too small ?, obstruction ? etc)
A: alkalosis (may cause apnea) or anxiety
N: neuromuscular disease
O: obstruction, bronchospasm
W: wait !!!
Saturday, December 19, 2009
The Impella - minimally invasive, catheter-based cardiac assist device
The Impella is a minimally invasive, catheter-based cardiac assist device designed to directly unload the left ventricle, reduce myocardial workload and oxygen consumption, and increase cardiac output and coronary and end-organ perfusion.
The Impella can be inserted into the left ventricle in a Cath Lab via a standard guidewire through the femoral artery, into the ascending aorta, across the valve and into the left ventricle.The tip of the catheter contains a “pigtail” that crosses the patient’s heart valve and rests in the left ventricle, generating flows up to 2.5 L/min. The Impella is hemocompatible, does no compromise to valve function. There is low hemolysis, bleeding, and stroke rates.
Friday, December 18, 2009
Thursday, December 17, 2009
Q: Lab call you with result that patient's pleural fluid has cholesterol level more than 45 mg/dL (1.16 mmol/L). What does it mean?
A; Pleural fluid is probably an exudate.
Using a cutoff point of 45 mg/dL for pleural cholesterol and/or LDH over 200 IU/L identified exudates with a sensitivity of 99% and a specificity of 98%.
Measurement of Pleural Fluid Cholesterol and Lactate Dehydrogenase - A Simple and Accurate Set of Indicators for Separating Exudates From Transudates - CHEST November 1995 vol. 108, no. 5 1260-1263
Wednesday, December 16, 2009
Q: What is the mechanism of action of Mannitol in control of Intracranial Hypertension (Increase ICP)?
A; Immediately after bolus administration Mannitol expands circulating volume by help of osmotic forces, decreases blood viscosity, resulting in reflex vasoconstriction and lowering of intracranial pressure. Its osmotic properties take effect in 15-30 minutes when it sets up an osmotic gradient and draws water out of neurons.
Tuesday, December 15, 2009
Tuesday December 15, 2009
Q: Does Phenytoin (Dilantin) get cleared by hemodialysis or hemoperfusion?
A; No (clinically insignificant removal)
- In Phenytoin toxicity/overdose, Hemodialysis or hemoperfusion are ineffective for enhancing elimination.
- Hemodialysis patients do not require extra dosing post dialysis though require frequent monitoring due to lower albumin level.
Monday, December 14, 2009
Abnormal sleep and errors more common in ICU nurses
Intensive care unit (ICU) nurses are more likely than floor nurses to have abnormal sleep and to experience a drop in vigilance during their shift that could impair patient safety, according to study findings presented at the CHEST 2009 meeting in San Diego, California.
"Nurses working in the ICU tend to have abnormal sleep and tend to have a greater frequency of errors across the length of their shift," lead researcher Dr. Salim R. Surani said. "These findings could be explained on the basis of the ICU nurses having a more impaired sleep quality as seen by PSQI (Pittsburg Sleep Quality Index), and perhaps having a more demanding and intensive work schedule in the ICU as compared to the floor."
Dr. Surani and colleagues from Baylor College of Medicine, Houston assessed ICU and floor nurses using the psychomotor vigilance test (PVT)
- ICU nurses made more errors at both the beginning and end of their shift than did floor nurses.
- As their shifts progressed, the ICU nurses made more errors (p = 0.029), while floor nurses showed no change.
- ICU nurses had significantly worse PSQI scores than did floor nurses (p = 0.041).
- Scores on the Epworth and Stanford sleepiness scales, however, were similar in the two groups
Dr. Salim Surani is co-editor of this website and extensively published on 'sleep'.
Sunday, December 13, 2009
Q: Describe relationship between Hypoxemia and acute Decompensated Right Ventricular Failure?
Answer: Oxygen is the most potent pulmonary vasodilator and liberal oxygen administration will reduce pulmonary vascular resistence and improve cardiac output.
Saturday, December 12, 2009
The influence of white noise on sleep in subjects exposed to ICU noise
Background and purpose: There is disagreement in the literature about the importance of sleep disruption from intensive care unit (ICU) environmental noise. Previous reports have assumed that sleep disruption is produced by high-peak noise. This study aimed to determine whether peak noise or the change in noise level from baseline is more important in inducing sleep disruption. We hypothesized that white noise added to the environment would reduce arousals by reducing the magnitude of changing noise levels.
Patients and methods: Four subjects underwent polysomnography under three conditions: (1) baseline, (2) exposure to recorded ICU noise and (3) exposure to ICU noise and mixed-frequency white noise, while one additional subject completed the first two conditions. Baseline and peak noise levels were recorded for each arousal from sleep.
Results: A total of 1178 arousals were recorded during these studies. Compared to the baseline night (13.3±1.8arousals/h) the arousal index increased during the noise (48.4±7.6) but not the white noise/ICU noise night (15.7±4.5). The change in sound from baseline to peak, rather than the peak sound level, determined whether an arousal occurred and was the same for the ICU noise and white noise/ICU noise condition (17.7±0.4 versus 17.5±0.3DB, P=0.65).
Conclusions: Peak noise was not the main determinant of sleep disruption from ICU noise. Mixed frequency white noise increases arousal thresholds in normal individuals exposed to recorded ICU noise by reducing the difference between background noise and peak noise.
The influence of white noise on sleep in subjects exposed to ICU noise - Sleep Medicine, Volume 6, Issue 5, Pages 423-428 (September 2005)
Friday, December 11, 2009
Friday December 11, 2009
Q: What is the easy (and quick) way of knowing ideal body weight at bedside?
Answer: Ideal weight can be calculated as follows:
- Men = 106 lb for 5 feet in height plus 6 lb for each additional inch.
- Women = 100 lb for 5 feet in height plus 5 lb for each additional inch.
Nutrition Management in the ICU - CHEST May 1999 vol. 115 no. suppl 2 145S-148S
Thursday, December 10, 2009
Q: Name few treatment modalities in Status Asthmaticus if all conventional treatments including mechanical ventilation fails?
Ketamine: has been shown to improve airway resistance, particularly the lower airways, as well as improve lung compliance. Dose: loading dose of 1 mg/kg (IV), followed by a continuous infusion of 1 mg/kg/hr for 2h. Peak airway pressure, PaCO2 and PaO2 should be monitored.
Deep anesthesia: such as with halothane or enflurane in combination with propofol or ketamine, may also be effective treatment as potent bronchodilators.
Nitric oxide: has also been used in isolated case reports.
Nebulized lidocaine: in combination with albuterol or levalbuterol is effective in helping the vocal cord dysfunction that may accompany status asthmaticus.
ECMO: Extracorporeal life support in patients with status asthmaticus when everything fails.
Reference: Click to get abstract
Use of ketamine in severe status asthmaticus in intensive care unit. Iran J Allergy Asthma Immunol. Dec 2003;2(4):175-80
Anaesthetic management in asthma. Minerva Anestesiol. Jun 2007;73(6):357-65.
Life-threatening status asthmaticus treated with inhaled nitric oxide - The Journal of Pediatrics, Volume 137, Issue 1, Pages 119-122
Emergency extracorporeal life support for asphyxic status asthmaticus. Respir Care. Nov 2007;52(11):1525-9.
Wednesday, December 9, 2009
Q: Which liquid is used in Liquid Ventilation?
Answer: Liquid ventilation is accomplished through a liquid called perfluorocarbon (PFC). Perflubron has several unique characteristics that make it very efficient in ventilation and oxygenation.
- Perflubron is an excellent medium to carry respiratory gases. PFC at one atmosphere of pressure can carry 20 times as much oxygen than saline.
- It can be used as a surfactant product in premature infants, or in patients with ARDS or lung injury. In an ARDS patient, surface tension in the lung is noted to be 67 to 75 dynes/cm. In a lung with perflubron, the surface tension is only 18 dynes/cm which helps prevent alveolar collapse and reduces alveolar opening pressures.
- It will spread uniformly and quickly throughout the lungs when being used for treatment of ARDS or as a surfactant. PFCs are almost twice as dense as water. It will tend to circulate in dependant areas and those areas where gas exchange is most diminished. This characteristic is useful in the removal of pulmonary edema.
- The components of PFCs are not taken up by the body but evaporated by the lungs. Continuous administration may be necessary to maintain an adequate dosage. This is allowable because it does not break down into toxic metabolites like high concentrations of gaseous oxygen.
Tuesday, December 8, 2009
Life-threatening sodium valproate overdose: A comparison of two approaches to treatment
Objectives: To describe two identical cases of severe sodium valproate overdose treated with two different approaches.
Design: Case report and review of the literature.
Patients: Two cases of identical life-threatening valproate (VPA) overdose with high VPA blood levels, markedly elevated ammonia levels and coma.
- One patient was treated with supportive therapy alone until the development of cerebral edema and seizures;
- the other was treated with immediate extended hemodialysis followed by high-volume hemodiafiltration.
Measurements and Main Results: The first patient remained critically ill with elevated VPA and ammonia levels until the development of seizures and life-threatening cerebral edema. After the delayed application of hemofiltration, the patient slowly recovered to be discharged from intensive care on day 11. In contrast, the second patient's VPA and ammonia levels rapidly declined with hemodialysis and hemodiafiltration with rapid clinical improvement and intensive care discharge on day 3.
Conclusions: In severe VPA overdose, early intervention with blood purification of suitable intensity was associated with a rapid reduction in VPA and ammonia levels and clinical improvement. This improvement was not seen with supportive therapy alone.
Life-threatening sodium valproate overdose: A comparison of two approaches to treatment - Critical Care Medicine: December 2009 - Volume 37 - Issue 12 - pp 3161-3164
Monday, December 7, 2009
Q: What percentage of patients may experience post extubation stridor (PES)?
Answer: About 15%
A low cuff-leak volume (less than 130 ml or 12%) around the endotracheal tube prior to extubation is useful in identifying patients at risk for post-extubation stridor.
Racemic Epinephrine, Heliox and and Decadron has been used as treatment for PES. It may require re-intubation in severe cases.
Sunday, December 6, 2009
Q: 54 year old asian male presented to ED with cough and left sided chest pain. CXR showed pleural effusion. Radiologist call you with the result adding "there is relative enlargement of the left sided ribs". What does it imply?
Answer: Chronic pleural effusion
The most common cause is tuberculosis and require close workup and possible isolation. Changes in the ribs of patients with tuberculosis as well as the other patients with chronic effusion are due to local hyperemia from an adjacent inflammatory process. In advanced cases, the affected side of the thorax is also contracted, so gravitational and postural factors might also play a role.
Remember these rib changes are not case of direct or metastisize skeletal tuberculosis as there is no destruction of bone.
Reference: Click to get article
Rib Enlargement in Patients with Chronic Pleural Disease - AJR:167, October 1996
Saturday, December 5, 2009
Q: What is Haldane effect?
Answer: The Haldane effect (named after John Scott Haldane) describe that deoxygenation of the blood increases its ability to carry carbon dioxide. Conversely, oxygenated blood has a reduced capacity for carbon dioxide.
The Haldane effect promotes dissociation of carbon dioxide from hemoglobin in the presence of oxygen. In the oxygen-rich capillaries of the lung, this property causes the displacement of carbon dioxide to plasma as venous blood enters the alveolus and is vital for alveolar gas exchange.
This partially explains the observation that some patients with emphysema might have an increase in PaCO2 following administration of supplemental oxygen even if content of CO2 stays equal.
Oxygenation of Hb promotes dissociation of H+ from Hb, which shifts the bicarbonate buffer equilibrium towards CO2 formation; therefore, CO2 is released from RBCs.
Friday, December 4, 2009
Pulmonary Artery Catheter in Amniotic fluid embolism !!
20 years ago it was suggested by Mason that probable diagnosis of Amniotic fluid embolism can be made by analyzing pulmonary artery blood with the logic that amniotic fluid does not ordinarily enter the maternal circulation, and the identification of large numbers of fetal squamous in the postpartum pulmonary microvasculature is of clinical significance. (He applied similar argument for other similar diseases such as fat embolism). Diagnosis becomes more probable if other fetal debris such as mucin or hair is present.
Technique described: Obtain blood from the distal lumen of a pulmonary artery catheter (in wedged position). After discarding the first 10 ml of blood, draw an additional 10 ml, heparinize and analyze utilizing Papanicolaou's method.Above technique is only suggestive of amniotic fluid embolism and not a gold standard.
Power Point Presentation: AMNIOTIC FLUID EMBOLISM
References: Click to get abstract/article
1. Pulmonary microvascular cytology. A new diagnostic application of the pulmonary artery catheter - Chest, V. 88, 908-14
2. Amniotic fluid embolism - Masson RG - Clin Chest Med.1992 Dec;13(4):657-65.
Thursday, December 3, 2009
Q: What is Scombroidosis?
Answer: Scombroidosis refers to histamine poisoning from the ingestion of fish improperly stored at an elevated temperature. Histamine and cis-urocanic acid are produced by various bacteria that multiply in the spoiled fish.
Patients usually present with a frightening flush but no urticaria, palpitations, syncope, nausea, vomiting, or diarrhea.
Wednesday, December 2, 2009
Q: How to make IABP more visible radiographically (on CXR) after insertion?
Answer: Shoot CXR on standby mode.
As in stand by mode there is no movement of baloon, chances to have better capture of IABP tip is high.
Tuesday, December 1, 2009
Q: Name at least 3 Antibiotics which should be use with caution in patients with active seizure?
2. Primaxin (Imipenem and Cilastatin)