Dr. Rick Albert on Prone Positioning

[cs_section id=”” class=” ” style=”margin: 0px; padding: 45px 0px; ” visibility=”” parallax=”false”][cs_row id=”” class=” ” style=”margin: 0px auto; padding: 0px; ” visibility=”” inner_container=”true” marginless_columns=”false” bg_color=”” marginlesscolumns=””][cs_column id=”” class=”” style=”padding: 0px; ” bg_color=”” fade=”false” fade_animation=”in” fade_animation_offset=”45px” fade_duration=”750″ type=”1/1″][cs_text id=”” class=”” style=”” text_align=”none”]Master Clinician and Researcher, Dr. Rick Albert discusses prone ventilation, its mechanisms, and why we should use it. [/cs_text][/cs_column][/cs_row][/cs_section][cs_section id=”” class=” ” style=”margin: 0px; padding: 0 0px 45px; ” visibility=”” parallax=”false”][cs_row id=”” class=” ” style=”margin: 0px auto; padding: 0px; ” visibility=”” inner_container=”true” marginless_columns=”false” bg_color=”” marginlesscolumns=””][cs_column id=”” class=”” style=”padding: 0px; ” bg_color=”” fade=”false” fade_animation=”in” fade_animation_offset=”45px” fade_duration=”750″ type=”1/1″][cs_text id=”” class=”” style=”” text_align=”none”][/cs_text][cs_text id=”” class=”” style=”” text_align=”none”][/cs_text][/cs_column][/cs_row][/cs_section][cs_section id=”” class=” ” style=”margin: 0px; padding: 45px 0px; ” visibility=”” parallax=”false”][cs_row id=”” class=” ” style=”margin: 0px auto; padding: 0px; ” visibility=”” inner_container=”true” marginless_columns=”false” bg_color=”” marginlesscolumns=””][cs_column id=”” class=”” style=”padding: 0px; ” bg_color=”” fade=”false” fade_animation=”in” fade_animation_offset=”45px” fade_duration=”750″ type=”1/1″][cs_text id=”” class=”” style=”” text_align=”left-text”]

Clinical Pearls

• Prone position increases PaO2- on average 70 torr increase. 20% of patients don’t improve PaO2 when placed in prone position.
• Gravitational gradient of pleural pressure in supine position is 0.5 cm H₂0 per 1 cm distance. Reduced gravitational gradient in prone position. In injured lung (ALI) see positive increase in pleural pressure- in prone position see less change in pleural pressure/gradient (pressure in dependent lung region is less positive in prone position). With more positive pleural pressure, FRC varies because of lung pressure volume curve.
• The reason why it works is not based upon redistribution of Q (i.e. prone position does not redistribute Q to the ventral lung region).
• Weight of lung greater in dorsal lung than ventral lung in supine position. When proned, bulk of lung weight is at the top instead of the bottom. “Compressive effects of the lung.” 41% of left lung under the heart (Albert, AJRCCM, 2000) and possible due to larger cardiac size in ARDS 64% of LLL under the heart in supine position. In prone position the heart does not SIT ON THE LUNG, IT SITS on the sternum. Thus, in supine position due to weight of heart, the part of the lung under the heart takes a higher alveolar pressure to get to the same inspiratory volume.
• Also, in prone position, decrease lung compression from abdominal contents.
• Prone position Improves Dorsal Lung V/Q (reduced shunt physiology).
• Mechanisms for improvement in PaO2 in Prone Position: 1) Less airways closure in dorsal lung (less atelectasis); 2)  Perfusion to dorsal lung maintained; 3) Decrease shunt and low V/Q; 4)     Improves V/Q matching
• How Does Prone Ventilation Improve Survival: Reduces VILI (Dr. Albert’s theory)
• Can prone positioning prevent ARDS? Constant TV ventilation depletes surfactant which leads to increased surface tension which then leads to atelectasis. New studies underway.

• 5 RCTs on Prone positioning:

1. Gattinoni L, Tognoni G, Pesenti A, Taccone P, Mascheroni D, Labarta V, Malacrida R, Di Giulio P, Fumagalli R, Pelosi P, Brazzi L, Latini R; Prone-Supine Study Group. N Engl J Med 2001. Aug 23; 345 (8): 568-73. Improved oxygenation, but no effect on mortality (trend toward decreased mortality). Patients proned 7 hours per day, instituted late, underpowered to detect mortality difference.
2. Guerin C, Gaillard S, Lemasson S, Ayzac L, Girard R, Beuret P, Palmier B, Le QV, Sirodot M, Rosselli S, Cadiergue V, Sainty JM, Barbe P, Combourieu E, Debatty D, Rouffineau J, Ezingeard E, Millet O, Guelon D, Rodriguez L, Martin O, Renault A, Sibille JP, Kaidomar M. JAMA 2004. Nov 17; 292 (19): 2379-87. Enrolled patients within 60 – 80 hours of diagnosis, proned 8 hours per day, only 51% patients with ARDS/ALI. Improved oxygenation, no effect on mortality.
3. Mancebo J, Fernandez R, Blanch L, Rialp G, Gordo F, Ferrer M, Rodriguez F, Garro P, Ricart P, Vallverdu I, Gich I, Castano J, Saura P, Dominguez G, Bonet A, Albert RK. A multicenter trial of prolonged prone ventilation in severe acute respiratory distress syndrome. Am J Respir Crit Care Med. 2006 Jun 1; 173 (11): 1233-9.  Enrolled within 48 hours, proned 17 hours per day. Improved oxygenation decreased ICU mortality when adjusted for severity of illness, underpowered.
4. Taccone P, Pesenti A, Latini R, Polli F, Vagginelli F, Mietto C, Caspani L, Raimondi F, Bordone G, Lapichino G, Mancebo J, Guerin C, Ayzac L, Blanch L, Fumagalli R, Tognoni G, Gattinoni L; Prone-Supine II Study Group. JAMA. 2009 Nov 11; 302(18): 1977-84. Enrolled within 72 hours, proned 18 hours per day, TV 8 cc/kg. Improved oxygenation but no mortality benefit. 12% of supine group ventilated prone, high complication rate.
5. Guerin C, Reignier J, Richard JC, Beuret P, Gacouin A, Boulain T, Mercier E, Badet M, Mercat A, Boudin O, Clavel M, Chatellier D, Jaber S, Rosselli S, Mancebo J, Sirodot M, Hilbert G, Bengler C, Richecoeur J, Gainnier M, Bayle F, Bourdin G, Leray V, Girard R, Baboi L, Ayzac L; PROSEVA Study Group. N Engl J Med 2013. 2013 Jun 6; 368 (23): 2159-68. Proned 16 hours/day, P:F < 150, low TV ventilation used, improved 28 and 90 day mortality.

[/cs_text][/cs_column][/cs_row][/cs_section][cs_section id=”” class=” ” style=”margin: 0px; padding: 0 0px 45px; ” visibility=”” bg_color=”” parallax=”false”][cs_row id=”” class=” ” style=”margin: 0px auto; padding: 0px; ” visibility=”” inner_container=”true” marginless_columns=”false” bg_color=”” marginlesscolumns=””][cs_column id=”” class=”” style=”padding: 0px; border-style: groove; border-width: 0px; border-width: 1px; ” bg_color=”#e8e8e8″ fade=”false” fade_animation=”in” fade_animation_offset=”45px” fade_duration=”750″ type=”1/1″][cs_text id=”” class=”” style=”” text_align=”none”]Selected References:
1. Douglas WW, Rehder K, Beynen FM, Sessler AD, Marsh HM. Am Rev Respir Dis. 1977 Apr; 115(4): 559-667
2. Albert RK, Leasa D, Sanderson M, Robertson HT, Hlastala MP. The prone position improves arterial oxygenation and reduces shunt in oleic-acid-induced acute lung injury. Am Rev Respir Dis. 1987 Mar; 135 (3): 628-33. Examines mechanisms in animals.
3. Wiener CM, Kirk W, Albert RK. Prone position reverses gravitational distribution of perfusion in dog lungs with oleic acid-induced injury. J Appl Physiol. 1990 Apr; 68(4): 1386-92.
4. Langer M, Mascheroni D, Marcolin R, Gattinoni L. The prone position in ARDS patients. A clinical study. Chest. 1988 Jul; 94 (1): 103-7. First human study on prone effects in ARDS.
5. Albert RK. Prone position in ARDS: what do we know, and what do we need to know? Crit Care Med. 1999 Nov; 27(11): 2574-5.
6. Mutoh T, Guest RJ, Lamm WJ, Albert RK. Prone position alters the effect of volume overload on regional pleural pressures and improves hypoxemia in pigs in vivo. Am Rev Respir Dis. 1992 Aug; 146 (2): 300-6.
7. Lamm WJ, Graham MM, Albert RK. Mechanism by which the prone position improves oxygenation in acute lung injury. Am J Respir Crit Care Med. 1994 Jul; 150(1): 184-93.
8. Albert RK, Hubmayr RD. The prone position eliminates compression of the lung by the heart. Am J Respir Crit Care Med 2000 May; 161(5): 1660-5. One of Dr. Albert’s favorite studies!
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