Sunday August 17, 2008
PEEP reduces incidence of VAP in nonhypoxemic patients


Very interesting article to analyze the effect on clinical outcomes of prophylactic positive end expiratory pressure in nonhypoxemic ventilated patients. It was a multicenter randomized controlled clinical trial from one trauma and two general ICUs in two university hospitals.

Patients: 132 mechanically ventilated patients with normal chest radiograph and Pao2/Fio2 above 250

Interventions: Patients were randomly allocated to receive mechanical ventilation with

• 5-8 cm H2O of PEEP (PEEP group, n = 66) or
• no-PEEP (control group, n = 65)

Results:

• Hospital mortality rate was similar
• Ventilator-associated pneumonia was detected in 16 (25.4%) patients in the control group and 6 (9.4%) in the PEEP group
• The number of patients who developed hypoxemia was significantly higher in the control group (34 of 63 patients, 54%) than in the PEEP group (12 of 64, 19%) and
• the hypoxemia developed after a shorter period in the control group than in the PEEP group (38 [20-70] hrs vs. 77 [32-164] hrs).
• Groups did not significantly differ in incidence of ARDS (14% in controls vs. 5% in the PEEP group), barotrauma (8% vs. 2%, respectively), or atelectasis (27% vs. 19%, respectively)

Conclusions: These findings indicate that application of prophylactic PEEP in nonhypoxemic ventilated patients reduces the number of hypoxemia episodes and the incidence of ventilator-associated pneumonia.


Reference: Click to get article

Positive-end expiratory pressure reduces incidence of ventilator-associated pneumonia in nonhypoxemic patients - Critical Care Medicine. 36(8):2225-2231, August 2008.

Saturday August 16, 2008
SEROTONIN SYNDROME

Serotonin syndrome is a potentially lethal condition caused by overstimulation of central and peripheral serotonin receptors. SSRI, MAOI and other antidepressants are the biggest culprits. (Everybody seems to be on some type of antidepressant these days!). Mild cases of serotonin syndrome may present with nausea, vomiting, flushing, and diaphoresis. Severe cases may present with hyperreflexia, myoclonus, muscular rigidity, hyperthermia, and autonomic instability. Diagnosis is clinical and no lab tests are available.

Treatment include discontinuation of all serotonergic medications. The initial treatment of serotonin syndrome is with benzodiazepines and cyproheptadine. Cyproheptadine (Periactin) appears to be the most effective antiserotonergic agent in humans. The initial dose is 4 - 8 mg PO. This dose can be repeated in 2 hrs if no response is noted to the initial dose. Periactin therapy should be discontinued if no response is noted after 16 mg has been administered. Patients who respond to cyproheptadine are usually given 4 mg every 6 h for 48 h to prevent recurrences. Dantrolene (0.5-2.5 mg/kg IV every 6 h, maximum 10 mg/kg per 24 h or 50 to 100 mg bid PO) is a nonspecific muscle relaxant that is used occasionally in serotonin syndrome, presenting with hyperthermia.

Here are 2 review articles for reference

1. Serotonin syndrome from McGill University, Montreal. CMAJ • May 27, 2003; 168 (11) followed with letter Serotonin syndrome: not a benign toxidrome CMAJ • September 16, 2003; 169 (6)
2. The Serotonin Syndrome - NEJM, March 2005 Volume 352:1112-1120

Friday August 15, 2008
Role of High frequency oscillatory ventilation in Trauma

Recent study by Funk in Journal of trauma-injury & critical care helped to shed light on this area.

Background: Severe pulmonary contusions are a common cause of acute respiratory distress syndrome (ARDS) and are associated with significant morbidity. High frequency oscillatory ventilation (HFOV) is a ventilatory mode that employs a lung protective strategy consistent with the ARDSNet low tidal volume ventilation strategy and may result in reduced morbidity. The objective of this report is to examine the impact of HFOV on blunt trauma patients with severe pulmonary contusions who failed or were at a high risk of failing conventional mechanical ventilation.

Methods: We undertook a retrospective chart review of all patients at our institution who received HFOV for severe pulmonary contusions. Patients were placed on HFOV when their mean airway pressure (mPaw) surpassed 30 cm H2O and their FIO2 was greater than 0.6. Serial determinations were made upto 72 hours of

• oxygenation index (OI) and
• the Pao2/FIO2 ratio (P/F)

A linear mixed model was used to analyze the slope ([beta]) of the regression line of P/F versus time and that of OI versus time.

Results: 17 patients were identified who underwent HFOV for ARDS due primarily to pulmonary contusions.

• P/F increased significantly after HFOV was initiated ([beta] = 12.1
• OI significantly decreased after HFOV implementation ([beta] = -1.8
• Mortality rate was 17.6%

Conclusions: The early use of HFOV appears to be safe and efficacious in blunt trauma patients sustaining pulmonary contusions, and results in a rapid improvement in OI and the P/F ratio.



Reference: click to get abstract

Funk D, Lujan E, Moretti EW, Davies J, Young C, Patel M, Vaslef S. A brief report: The use of high-frequency oscillatory ventilation for severe pulmonary contusion. Journal of Trauma-Injury & critical Care 2008; 65(2): 390-395

Thursday August 14, 2008

Q: Citrate is used in continuous renal replacement therapy (CRRT) for extracorporeal anticoagulation. What is the added advantage of using citrate?

Answer: Citrate partially enters the systemic circulation. Apart from being an anticoagulant, citrate is a buffer substrate. The generation of buffer is related to the conversion of sodium citrate to citric acid:

Na3 citrate + 3H2CO3 = citric acid + 3NaHCO3

Citric acid enters the mitochondria and is metabolized in the Krebs cycle, mainly in the liver but also in skeletal muscle and the renal cortex, leaving sodium bicarbonate.

Related Pearl: Citrate in CRRT

Reference: Click to get article

Clinical review: Patency of the circuit in continuous renal replacement therapy- Critical Care 2007, 11:218

Monday August 11, 2008

Case: 38 year old female with cervical cancer and undergoing chemotheraphy is admitted with dehydration secondary to chemotherapy-induced nausea and vomiting (CINV). According to patient standard anti nausea medications including zofran (ondansetron), compazine (prochlorperazine) or phenergan doesn't work. Which 'trick' or cocktail usually works in such resistant nausea?

Answer: ABH Cocktail

ABH (Ativan, Benadryl and Haldol) cocktail is effective in resistant nausea particularly in chemotherapy-induced nausea and vomiting (CINV). It is available in capsule, suppository as well as in transdermal gel form. If needed can be given in IV mix over 15 minutes. Extended form is called "ABHR" with addition of Reglan (metoclopramide). Usual IV dose is

• Ativan (lorazepam) = 0.5 mg,
• Benadryl (diphenhydramine) = 12.5 mg,
• Haldol (haloperidol) = 0.5 mg and
• Reglan (metoclopramide)= 5-10 mg

Doses can be escalated in oral and gel form if needed upto lorazepam 4 mg/ diphenhydramine 100 mg/haloperidol 4 mg/metoclopramide 80 mg per ml.

Sunday August 10, 2008

Case: 28 year old male has been brought to ED with possible ethylene glycol toxicity. Osmol gap is greater than 10 mOsm/L and reportedly urinary oxalate crystals are present. Unfortunately, Fomepizole is not available and you decide to treat patient with Ethanol. Before initiating treatment which lab value you would like to see?

Answer: ethanol level itself

Its not uncommon to have both Ethanol and Ethylene Glycol ingestion together. Overly aggressive ethanol administration may cause apnea that required intubation.

Goal is to maintain blood ethanol levels 100-150 mg/dL. Measuring initial blood level is important; if more than 100 mg/dL, loading dose may be unnecessary.

Doses:
IV loading dose: 7-10 mL/kg IV of 10% ethanol (V/V) in dextrose 5% in water over 30 min to achieve blood ETOH concentration of 100-130 mg/dL (21.7-28.2 mmol/L)
Oral loading dose: 1 mL/kg of 95% ethanol mix with orange juice over 30 min
Average maintenance PO dose: 0.15 mL/kg/h of 95% ETOH
Average maintenance IV dose:1.5 mL/kg/h of a 10% solution

Saturday August 9, 2008
3 "NOs" in organophosphate poisoning

Due to their very common usage in ICU, there may be a reflex tendency to use following 3 medications. But its better to avoid them as they may increase the toxicity of the organophosphate exposure.

1. Avoid succinylcholine for intubation *
2. Avoid loop diuretics for increased pulmonary secretions/congestion
3. Avoid morphine for analgesia

* see related previous pearl here

Friday August 8, 2008
Combined milrinone and enteral metoprolol therapy in septic myocardial depression

A very interesting study to counter septic cardiomyopathy.

Methods:This retrospective analysis summarizes preliminary clinical experience with the combined use of milrinone and enteral metoprolol therapy in forty patients with septic shock and cardiac depression. In all study patients, beta blockers were initiated only after stabilization of cardiovascular function in order to decrease heart rate less than 95 bpm. Hemodynamic data and laboratory parameters were extracted from medical charts and documented before, 6, 12, 24, 48, 72, and 96 hours after the first metoprolol dosage. Adverse cardiovascular events were documented.

Patients with other causes of shock or cardiac failure, patients with beta-blocker therapy initiated more than 48 hrs after shock onset and patients with pre-existent decompensated congestive heart failure were excluded.

Results

• Heart rate control (65-95 bpm) was achieved in 97.5% of patients (n=39) within 12.2+/-12.4 hrs.
• Heart rate, central venous pressure, norepinephrine, arginine vasopressin and milrinone dosages decreased.
• Cardiac index and cardiac power index remained unchanged, while stroke volume index increased
• Norepinephrine and milrinone dosages were increased in nine (22.5%) and six (15%) patients, respectively.
• PH increased, while arterial lactate, serum C-reactive protein and creatinine levels decreased during the observation period
• Twenty-eight day mortality was 33%
  

In two patients (5%) metoprolol was discontinued because of asymptomatic bradycardia

Conclusions: Low doses of enteral metoprolol in combination with phosphodiesterase inhibitors are feasible in patients with septic shock and cardiac depression but no overt heart failure.

Reference: click to get article

Combined milrinone and enteral metoprolol therapy in patients with septic myocardial depression - Critical Care 2008, 12:R99 - pdf file

Thursday August 7, 2008
Does Non Invasive ventilation improve short term mortality in patients with acute cardiogenic pulmonary edema??


In a study published in NEJM by Alasdair gray they studied the above issue. A total of 1069 patients were assigned to

• Standard oxygen therapy (367 patients),
• CPAP (346 patients), or
• NIPPV (356 patients)

Standard oxygen therapy, CPAP (5 to 15 cm of water), or NIPPV (inspiratory pressure, 8 to 20 cm of water; expiratory pressure, 4 to 10 cm of water)


Results:

• There was no significant difference in 7-day mortality between patients receiving standard oxygen therapy (9.8%) and those undergoing noninvasive ventilation (9.5%, P=0.87).
• There was no significant difference in the combined end point of death or intubation within 7 days between the two groups of patients undergoing noninvasive ventilation (11.7% for CPAP and 11.1% for NIPPV, P=0.81).
• As compared with standard oxygen therapy, noninvasive ventilation was associated with greater mean improvements at 1 hour after the beginning of treatment in patient-reported dyspne , heart rate, acidosis and hypercapnia.
• There were no treatment-related adverse events

Conclusions: In patients with acute cardiogenic pulmonary edema, noninvasive ventilation induces a more rapid improvement in respiratory distress and metabolic disturbance than does standard oxygen therapy but has no effect on short-term mortality



Reference: click to get abstract

Gray A, Goodacre S, Newby DE, Masson M, Sampson F, Nicholl J. Noninvasive ventilation in acute cardiogenic pulmonary edema. NEJM July 10th 2008; 359: 142-151

Wednesday August 6, 2008

Q; Which condition may mimic pseudo-atrial flutter on EKG and on monitor?


A; Parkinsonian tremor (first reported about 40 years ago 1 and later on many other reports confirmed it).

In literature, cases have been reported of pseudo atrial flutter with use of electronic devices by patient. 2


References:

1. MUSCLE-TREMOR ARTIFACT DUE TO PARKINSON'S SYNDROME. IT STIMULATED ATRIAL FLUTTER AND DISAPPEARED DURING SLEEP - Postgrad Med. 1965 Jun;37:718-20.
2. Atrial flutter simulated by a portable CD player - mayo clinic proceedings - march 2006,82(3), Page 383 -pdf file

Tuesday August 5, 2008
Can we predict who needs ICU admission after Major Lung Resection


Study by Brunelli and his associates helped to address that issue.

Background: We aimed to develop and validate a scoring system to predict intensive care unit (ICU) admission for complications after major lung resection for purposes of optimizing planning of resources for patient care.

Methods: Patients undergoing major lung resections performed between 2000 and 2006 at three thoracic surgery units were analyzed for unplanned admission to the ICU for complications. Variables were initially screened by univariate analysis. Selected variables were used in a stepwise logistic regression analysis that was validated by bootstrap analysis. The scoring system was developed by proportional weighting of the significant and reliable predictors estimates and validated on patients operated on in a different center.

ResuIts: In the derivation set of 1927 patients, 82 had ICU admission for complication, and 30 died (associated mortality rate 36.5%). Predictive variables and their scores were

* 2 points - pneumonectomy; and
* 1 point each for

• age older than 65,
• predicted post operative FEV1 below 65%,
• predicted post operative DLCO below 50%, and
• cardiac comorbidity
  

Patients were grouped into three classes based on their score, which were significantly associated with the incremental risk of ICU admission in the validation set of 349 patients.

Conclusion: It helps us in assessing and preparing for the post operative need for ICU and possible complications.

Reference:

Brunelli A, Ferguson MK, Rocco G, Pieretti P, et al. A Scoring System Predicting the Risk for Intensive Care Unit Admission for Complications After Major Lung Resection: A Multicenter Analysis. Ann Thorac Surg 2008;86:213-218.

Monday August 4, 2008
A randomized controlled trial of conventional versus automated weaning from mechanical ventilation using SmartCare/PS failed to show superiority for SmartCare/PS system

In a study by Lellouche published in 2006 AJRCCM (174;894-900) showed that SmartCare/PS was associated with a substantial reduction in the duration of ventilation and ICU length when compared to physician controlled weaning using local European guidelines.

SmartCare/PS monitors the patient’s respiratory status every 2 to 5 minutes (frequency, tidal volume, and end tidal CO2) and periodically adapts pressure support aiming for a safe efficient weaning process. The computerized SmartCare/PS establishes a respiratory status diagnosis, determines an intervention and then instructs the ventilator to decrease or increase the PS.

In a study by Louise Rose published in Intensive care Medicine they studied 102 patients.

• The median time from the first identified point of suitability for weaning to the state of separation potential using SmartCare/PS was 20 hrs as compared to 8hrs for the Control.
• The median time to successful extubation using SmartCare/PS was 43hrs as compared to 40 hrs with the Control.
• Study showed comparable rate of reintubation, tracheostomy, neuromuscular blockers usage and steroid use.

Conclusion: Substantial reductions in weaning duration with SmartCare/PS as previously demonstrated were not confirmed when compared to weaning managed by experienced critical care specialty nurses using 1:1 nurse to patient ratio. Majority of those nurses held a graduate critical care specialty qualification (Respiratory therapist are not employed in Australian context)



Reference:

Rose L, Presneill JJ, Johnston L, Cade JF. A randomized, controlled trial of conventional versus automated weaning from mechanical ventilation using SmartCare/PS. Intensive Care Med 2008

Sunday August 3, 2008
Interesting website

We try to keep our readers posted with "cool" medical websites. Following is a very well done website. It has

• Clinical Cases by Organ System
• Links to Examination Videos
• Links to Electrocardiograms, X-rays, CT scans
• Procedure Guides Step-by-Step

The web site is Clinical Cases and Images

( http://clinicalcases.blogspot.com/ )

Saturday August 2, 2008


Case: You have been called to ER to consult a critically ill 42 year old male who presented with mental status change and hypotension. Lab shows finding of pre-renal azotemia with acute renal failure (ARF). Wife reports chills and 'very very excessive sweating' since last 3 months, progressively getting worse. Patient was also reported to be hypothermic. Your diagnosis was simple septic shock and you argued about CT scan of head which was done by ER physician. Meanwhile, you received call from radiologist with report of CT head and he strongly recommends MRI of brain to confirm findings. You agreed and it showed agenesis of the corpus callosum. What is your diagnosis?

Diagnosis: Shapiro's Syndrome

Shapiro's Syndrome is characterised by recurrent episodes of hypothermia, hyperhidrosis and agenesis of the corpus callosum. Shapiro syndrome is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). Onset is typically in adulthood. Hyperhidrosis can be so severe that it may cause acute renal failure. Different treatments has been described including cyproheptadine, clonidine, glycopyrrolate or topiramate.


*Shapiro's Syndrome was first described by W. R. Shapiro, G.H. Williams and F. Plum in 1969.



References: Click to get abstract/article

1. Agenesis of the corpus callosum associated with paroxysmal hypothermia: Shapiro's syndrome. Neth J Med. 1997 Jan;50(1):29-35.
2. Clonidine therapy for Shapiro's syndrome. Q J Med. 1992 Mar;82(299):235-45.
3. HYPOTHALAMIC DYSFUNCTION IN SHAPIRO'S SYNDROME MAY CAUSE ABNORMALITIES OF THIRST AND APPETITE PERCEPTION Endocrine Abstracts (2002) 4 P24
4. Shapiro's Syndrome: A Renewed Appreciation for Vital Signs Clinical Infectious Diseases 2004;38:e107–e108

Friday August 1, 2008
ICU billing code inconsistency

See this very interesting study titled "Reliability of diagnostic coding in intensive care patients". Is this inconsistency because patients are too sick or we don't know, how to bill?

Introduction: Administrative coding of medical diagnoses in intensive care unit (ICU) patients is mandatory in order to create databases for use in epidemiological and economic studies. We assessed the reliability of coding between different ICU physicians.

Methods: One-hundred medical records selected randomly from 29,393 cases collected between 1998 and 2004 in the French multicenter Outcomerea ICU database were studied. Each record was sent to two senior physicians from independent ICUs who re-coded the diagnoses using the International Classification of Diseases - 10th revision (ICD-10) after being trained according to guidelines developed by two French national intensive care medicine societies, the French Society of Intensive Care Medicine (SRLF) and French Society of Anesthesiology and Intensive Care Medicine (SFAR). These codes were then compared to the original codes, which had been selected by the physician treating the patient. A specific comparison was done for the diagnoses of septicemia and shock.

Results: The ICU physicians coded an average of 4.6+/-3.0 (range 132) diagnoses per patient, with little agreement between the three coders.

• The primary diagnosis was matched by both external coders in 34% of cases, by only one in 35%, and by neither in 31%.
• Only 18% of all codes were selected by all three coders.
• Similar results were obtained for the diagnoses of septicemia and/or shock.

Conclusions: In a multicenter database designed primarily for epidemiological and cohort studies in ICU patients, the coding of medical diagnoses varied between different observers. This could limit the interpretation and validity of research and epidemiological programs using diagnoses as inclusion criteria.


References: Click to get abstract/article

1. Reliability of diagnostic coding in intensive care patients Critical Care 2008, 12:R95