Critical care: Difference between revisions
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;Alveolar-arterial oxygen (A-a) gradient (alveolar-arterial oxygen difference - AVO<sub>2</sub>D) | ;Alveolar-arterial oxygen (A-a) gradient (alveolar-arterial oxygen difference - AVO<sub>2</sub>D) | ||
The A-a gradient is harder to calculate, but accounts for changes in respiration as measured by the partial pressure of carbon dioxide. However, this calculation relies on the respiratory quotient being constant in the prediction of alveolar CO<sub>2</sub> When compared to the PF ratio, the A-a gradient is found to correlate less well with pulmonary shunting.<ref name="pmid6409506">{{cite journal |author=Covelli HD, Nessan VJ, Tuttle WK |title=Oxygen derived variables in acute respiratory failure |journal=Crit. Care Med. |volume=11 |issue=8 |pages=646–9 |year=1983 |pmid=6409506 |doi=}}</ref><ref name="pmid14769743">{{cite journal |author=El-Khatib MF, Jamaleddine GW |title=A new oxygenation index for reflecting intrapulmonary shunting in patients undergoing open-heart surgery |journal=Chest |volume=125 |issue=2 |pages=592–6 |year=2004 |pmid=14769743 |doi=}}</ref><ref name="pmid3191742">{{cite journal |author=Cane RD, Shapiro BA, Templin R, Walther K |title=Unreliability of oxygen tension-based indices in reflecting intrapulmonary shunting in critically ill patients |journal=Crit. Care Med. |volume=16 |issue=12 |pages=1243–5 |year=1988 |pmid=3191742 |doi=}}</ref> | The A-a gradient is harder to calculate, but accounts for changes in respiration as measured by the [[partial pressure]] of carbon dioxide. However, this calculation relies on the respiratory quotient being constant in the prediction of alveolar CO<sub>2</sub> When compared to the PF ratio, the A-a gradient is found to correlate less well with pulmonary shunting.<ref name="pmid6409506">{{cite journal |author=Covelli HD, Nessan VJ, Tuttle WK |title=Oxygen derived variables in acute respiratory failure |journal=Crit. Care Med. |volume=11 |issue=8 |pages=646–9 |year=1983 |pmid=6409506 |doi=}}</ref><ref name="pmid14769743">{{cite journal |author=El-Khatib MF, Jamaleddine GW |title=A new oxygenation index for reflecting intrapulmonary shunting in patients undergoing open-heart surgery |journal=Chest |volume=125 |issue=2 |pages=592–6 |year=2004 |pmid=14769743 |doi=}}</ref><ref name="pmid3191742">{{cite journal |author=Cane RD, Shapiro BA, Templin R, Walther K |title=Unreliability of oxygen tension-based indices in reflecting intrapulmonary shunting in critically ill patients |journal=Crit. Care Med. |volume=16 |issue=12 |pages=1243–5 |year=1988 |pmid=3191742 |doi=}}</ref> | ||
Among outpatients with possible pulmonary embolism, the A-a gradient may be a better test.<ref name="pmid8304364">{{cite journal |author=McFarlane MJ, Imperiale TF |title=Use of the alveolar-arterial oxygen gradient in the diagnosis of pulmonary embolism |journal=Am. J. Med. |volume=96 |issue=1 |pages=57–62 |year=1994 |pmid=8304364 |doi=}}</ref> | Among outpatients with possible pulmonary embolism, the A-a gradient may be a better test.<ref name="pmid8304364">{{cite journal |author=McFarlane MJ, Imperiale TF |title=Use of the alveolar-arterial oxygen gradient in the diagnosis of pulmonary embolism |journal=Am. J. Med. |volume=96 |issue=1 |pages=57–62 |year=1994 |pmid=8304364 |doi=}}</ref> |
Revision as of 23:35, 31 August 2008
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Critical care medicine is the "health care provided to a critically ill patient during a medical emergency or crisis".[1]
Monitoring the critically ill patient
Swan-Ganz catheterization
Respiration and oxygenation
- PaO2/FiO2 ratio (PF ratio)
This measure is easier to calculate. Comparative studies suggest it correlates better with pulmonary shunts than does the A-a gradient.[2][3][4]
- Alveolar-arterial oxygen (A-a) gradient (alveolar-arterial oxygen difference - AVO2D)
The A-a gradient is harder to calculate, but accounts for changes in respiration as measured by the partial pressure of carbon dioxide. However, this calculation relies on the respiratory quotient being constant in the prediction of alveolar CO2 When compared to the PF ratio, the A-a gradient is found to correlate less well with pulmonary shunting.[2][3][4]
Among outpatients with possible pulmonary embolism, the A-a gradient may be a better test.[5]
Treatments provided in the intensive care unit
Circulatory support
Respiratory support
Complications
Abdominal compartment syndrome
Abdominal compartment syndrome is associated with increased mortalty.[6]
Preventing complications in the critically ill patient
Glucose control
Randomized controlled trials of tight glucose control in the intensive and intraoperative care settings have produced mixed results.
Regarding surgical patients, a randomized controlled trial concluded "intensive insulin therapy to maintain blood glucose at or below 110 mg per deciliter reduces morbidity and mortality among critically ill patients in the surgical intensive care unit."[7]
Regarding medical patients, a randomized controlled trial concluded "intensive insulin therapy significantly reduced morbidity but not mortality among all patients in the medical ICU. Although the risk of subsequent death and disease was reduced in patients treated for three or more days, these patients could not be identified before therapy."[8] Regarding medical patients with septic shock, intensive insulin therapy and pentastarch increased adverse events in a randomized controlled trial.[9]
Generalizing from intraoperative control of glucose, a randomized controlled trial concluded "the increased incidence of death and stroke in the intensive treatment group raises concern about routine implementation of this intervention."[10]
Preventing anemia
Blood transfusion
There may not be a meaningful difference in outcomes between transfusing blood to maintain a hemoglobin > 7.0 g/dl versus a hemoglobin > 10.0 g/dl.[11]
Erythropoietin
A randomized controlled trial reported "epoetin alfa does not reduce the incidence of red-cell transfusion among critically ill patients, but it may reduce mortality in patients with trauma. Treatment with epoetin alfa is associated with an increase in the incidence of thrombotic events."[12]
Selective gastrointestinal decontamination
Systematic reviews conclude that selective decontamination of the digestive tract may reduce morbidity in critically ill patients[13][14][15] although some randomized controlled trials have[16][17][18] and others have not found benefit[19].
Preventing gastrointestinal tract ulceration
Preventing deep venous thrombosis
Preventing healthcare-associated pneumonia
Medical error in the intensive care
Regarding overlooked diagnosis among patients receiving artificial respiration in the intensive care, an autopsy study concluded "abdominal pathologic conditions--abscesses, bowel perforations, or infarction--were as frequent as pulmonary emboli as a cause of class I errors. While patients with abdominal pathologic conditions generally complained of abdominal pain, results of examination of the abdomen were considered unremarkable in most patients, and the symptom was not pursued." [20]
Predicting outcomes of adult patients
Although there is much research into prognosing patients in intensive care, patients are not very confident in thei accuracy of prognoses.[21]
Apache II score
http://www.sfar.org/scores2/apache22.html
SAPS II
References
- ↑ Anonymous. Critical care. National Library of Medicine. Retrieved on 2008-01-07.
- ↑ 2.0 2.1 Covelli HD, Nessan VJ, Tuttle WK (1983). "Oxygen derived variables in acute respiratory failure". Crit. Care Med. 11 (8): 646–9. PMID 6409506. [e]
- ↑ 3.0 3.1 El-Khatib MF, Jamaleddine GW (2004). "A new oxygenation index for reflecting intrapulmonary shunting in patients undergoing open-heart surgery". Chest 125 (2): 592–6. PMID 14769743. [e]
- ↑ 4.0 4.1 Cane RD, Shapiro BA, Templin R, Walther K (1988). "Unreliability of oxygen tension-based indices in reflecting intrapulmonary shunting in critically ill patients". Crit. Care Med. 16 (12): 1243–5. PMID 3191742. [e]
- ↑ McFarlane MJ, Imperiale TF (1994). "Use of the alveolar-arterial oxygen gradient in the diagnosis of pulmonary embolism". Am. J. Med. 96 (1): 57–62. PMID 8304364. [e]
- ↑ Malbrain ML, Chiumello D, Pelosi P, et al (February 2005). "Incidence and prognosis of intraabdominal hypertension in a mixed population of critically ill patients: a multiple-center epidemiological study". Crit. Care Med. 33 (2): 315–22. PMID 15699833. [e]
- ↑ van den Berghe G, Wouters P, Weekers F, et al (2001). "Intensive insulin therapy in the critically ill patients". N. Engl. J. Med. 345 (19): 1359–67. PMID 11794168. [e]
- ↑ Van den Berghe G, Wilmer A, Hermans G, et al (2006). "Intensive insulin therapy in the medical ICU". N. Engl. J. Med. 354 (5): 449–61. DOI:10.1056/NEJMoa052521. PMID 16452557. Research Blogging.
- ↑ Brunkhorst FM, Engel C, Bloos F, et al (2008). "Intensive insulin therapy and pentastarch resuscitation in severe sepsis". N. Engl. J. Med. 358 (2): 125–39. DOI:10.1056/NEJMoa070716. PMID 18184958. Research Blogging.
- ↑ Gandhi GY, Nuttall GA, Abel MD, et al (2007). "Intensive intraoperative insulin therapy versus conventional glucose management during cardiac surgery: a randomized trial". Ann. Intern. Med. 146 (4): 233–43. PMID 17310047. [e]
- ↑ Hébert PC, Wells G, Blajchman MA, et al (1999). "A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. Transfusion Requirements in Critical Care Investigators, Canadian Critical Care Trials Group". N. Engl. J. Med. 340 (6): 409–17. PMID 9971864. [e]
- ↑ Corwin HL, Gettinger A, Fabian TC, et al (2007). "Efficacy and safety of epoetin alfa in critically ill patients". N. Engl. J. Med. 357 (10): 965–76. DOI:10.1056/NEJMoa071533. PMID 17804841. Research Blogging.
- ↑ Chan EY, Ruest A, Meade MO, Cook DJ (2007). "Oral decontamination for prevention of pneumonia in mechanically ventilated adults: systematic review and meta-analysis". BMJ 334 (7599): 889. DOI:10.1136/bmj.39136.528160.BE. PMID 17387118. Research Blogging.
- ↑ Silvestri L, van Saene HK, Milanese M, Gregori D, Gullo A (2007). "Selective decontamination of the digestive tract reduces bacterial bloodstream infection and mortality in critically ill patients. Systematic review of randomized, controlled trials". J. Hosp. Infect. 65 (3): 187–203. DOI:10.1016/j.jhin.2006.10.014. PMID 17244516. Research Blogging.
- ↑ Silvestri L, van Saene HK, Milanese M, Gregori D (2005). "Impact of selective decontamination of the digestive tract on fungal carriage and infection: systematic review of randomized controlled trials". Intensive Care Med 31 (7): 898–910. DOI:10.1007/s00134-005-2654-9. PMID 15895205. Research Blogging.
- ↑ de Jonge E, Schultz MJ, Spanjaard L, et al (2003). "Effects of selective decontamination of digestive tract on mortality and acquisition of resistant bacteria in intensive care: a randomised controlled trial". Lancet 362 (9389): 1011–6. PMID 14522530. [e]
- ↑ Cockerill FR, Muller SR, Anhalt JP, et al (1992). "Prevention of infection in critically ill patients by selective decontamination of the digestive tract". Ann. Intern. Med. 117 (7): 545–53. PMID 1524328. [e]
- ↑ Stoutenbeek CP, van Saene HK, Little RA, Whitehead A (2007). "The effect of selective decontamination of the digestive tract on mortality in multiple trauma patients: a multicenter randomized controlled trial". Intensive Care Med 33 (2): 261–70. DOI:10.1007/s00134-006-0455-4. PMID 17146635. Research Blogging.
- ↑ Gastinne H, Wolff M, Delatour F, Faurisson F, Chevret S (1992). "A controlled trial in intensive care units of selective decontamination of the digestive tract with nonabsorbable antibiotics. The French Study Group on Selective Decontamination of the Digestive Tract". N. Engl. J. Med. 326 (9): 594–9. PMID 1734249. [e]
- ↑ Papadakis MA, Mangione CM, Lee KK, Kristof M (1991). "Treatable abdominal pathologic conditions and unsuspected malignant neoplasms at autopsy in veterans who received mechanical ventilation". JAMA 265 (7): 885–7. PMID 1992186. [e]
- ↑ Zier LS, Burack JH, Micco G, et al (August 2008). "Doubt and belief in physicians' ability to prognosticate during critical illness: the perspective of surrogate decision makers". Crit. Care Med. 36 (8): 2341–7. DOI:10.1097/CCM.0b013e318180ddf9. PMID 18596630. Research Blogging.
- ↑ Le Gall JR, Lemeshow S, Saulnier F (1993). "A new Simplified Acute Physiology Score (SAPS II) based on a European/North American multicenter study". JAMA 270 (24): 2957–63. PMID 8254858. [e]