Editorial
What’s new in emergencies, trauma and shock? Mechanical ventilation in trauma patients: A tight-rope walk! Medha Mohta Department of Anaesthesiology and Critical Care, University College of Medical Sciences and GTB Hospital, Delhi, India
A large proportion of trauma patients need mechanical ventilation. They are at a great risk of developing acute lung injury (ALI) and acute respiratory distress syndrome (ARDS).[1] Conditions like pulmonary contusion, shock, multiple transfusions, fractures, aspiration, near drowning, smoke inhalation, and fat embolism predispose trauma patients to development of ARDS. [1] Sometimes mechanical ventilation may be needed in the absence of lung injury, for example, a brain injured patient may require intubation and ventilation for airway protection or for prevention of secondary brain injury. Lung protective ventilation strategy using lower tidal volumes and plateau pressures with high positive end-expiratory pressure (PEEP) and permissive hypercapnia has become widely accepted for management of ALI and ARDS and the same is advocated for the majority of chest trauma patients. This strategy is aimed at preventing ventilator associated lung injury (VALI), which results from high lung volumes (volutrauma), high airway pressures (barotrauma), and repetitive opening and closing of collapsed lung units (atelectrauma). Lung injury can propagate proinflammatory cytokine cascade resulting in biotrauma.[2] All these problems can be avoided by adopting lung protective ventilation. However, the management becomes tricky when lung injury occurs in concurrence with head injury. ARDS develops in up to 20% patients suffering from severe head injury.[3] The ventilatory management goals for lung and brain injury are in conflict with each other. High PEEP and hypercapnia, Address for correspondence: Dr. Medha Mohta, E-mail: [email protected] Access this article online Quick Response Code: Website: www.onlinejets.org
DOI: 10.4103/0974-2700.125630
Journal of Emergencies, Trauma, and Shock I 7:1 I Jan - Mar 2014
major components of lung protective ventilatory strategy, can increase intracranial pressure (ICP) and reduce cerebral perfusion pressure (CPP), thus worsening the brain injury. Therefore one needs to use a very cautious and balanced approach to achieve good outcome in trauma patients. In this issue of JETS,. Arora, et al. have highlighted various ventilatory strategies used in trauma patients.[4] They have described common injuries to different organ systems and their management principles. Independent lung ventilation has an important role in cases of massive chest trauma where isolation of lungs is required. In most of the patients with traumatic injuries of chest, protective lung ventilatory strategy remains the basic principle. Some other ventilatory modes based on open lung concept, for example, airway pressure release ventilation (APRV), high frequency oscillatory ventilation (HFOV), and high frequency percussive ventilation (HFPV) also help in preventing and managing VALI. Extracorporeal membrane oxygenation (ECMO) provides rest to the lungs by facilitating gas exchange outside the body. Other newer techniques like closed loop ventilation seem to have potential for further improving ventilatory management of critically ill patients. APRV appears to be a promising technique that improves lung recruitment, oxygenation, end-organ blood flow, pulmonary vasoconstriction, and sedation requirements.[5] However, any reduction in mortality has not been proven; therefore trials directly comparing APRV with standard lung protective ventilation in ARDS/ALI patients are needed. There have been encouraging results from a recent animal study demonstrating that early application of APRV stabilizes alveoli, reduces alveolar edema, and thus prevents development of ARDS.[6] HFOV has been found to decrease mortality when compared with conventional ventilation. However, it is yet to be seen if it has any advantage over current lung protective ventilatory strategies.[7] Some retrospective studies have shown good results with HFPV in trauma patients having ARDS with or without 1
Mohta: Mechanical ventilation in trauma
head injury. This technique produced significant improvement in oxygenation with reduction in ICP during first 16 hours, when applied in head injured patients with ARDS.[3] However, further trials are required to evaluate the long-term outcome and reduction in mortality, if any. In patients with traumatic brain injury and ALI/ARDS, a strategic ventilatory approach, maintaining a balance between principles for brain injury management and protective lung ventilation is required. High levels of PEEP have a potential to increase intrathoracic pressure, thus decreasing cerebral venous drainage and in turn compromising cerebral perfusion. However, in case of noncompliant lungs, as is the situation in patients with ALI/ARDS, transmission of intrathoracic pressure to cranium and thus effect on cerebral perfusion is lesser.[8] Thus PEEP can be safely applied in this group of patients, provided the volume status and mean arterial pressure are maintained and the level of PEEP provided is lower than ICP.[8] The lowest level of PEEP that maintains oxygenation should be applied. Head elevation with avoidance of extreme neck rotation and tight endotracheal tube ties around the neck are quite helpful. However, arterial carbon dioxide tension plays an important role in determining cerebral blood volume, intracranial compliance, and ICP.[8] Hence hypercapnia should be avoided and all efforts should be made to maintain normocarbia. Thus the outcome of trauma patients can be improved by following principles of ventilatory management according to the organ systems involved. Further studies using newer ventilatory strategies are needed to find optimal solutions to the conflicts faced in polytrauma patients.
REFERENCES 1.
McCunn M, Sutcliffe AJ, Mauritz W, and the ITACCS Critical Care Committee. Guidelines for management of mechanical ventilation in critically injured patients. Available from: http://www.itaccs.com/ traumacare/archive/04_03_Fall_2004/guidelines_for_management.pdf. [Last accessed on 2013 Jul 28].
2.
Ritacca FV, Stewart TE. Clinical review: High-frequency oscillatory ventilation in adults - a review of the literature and practical applications. Crit Care 2003;7:385-90.
3.
Salim A, Miller K, Dangleben D, Cipolle M, Pasquale M. Highfrequency percussive ventilation: An alternative mode of ventilation for head-injured patients with adult respiratory distress syndrome. J Trauma 2004;57:542-6.
4.
Shubhangi Arora, Preet Mohinder Singh, Anjan Trikha. Ventilatory strategies in trauma patients. J Emerg Trauma Shock 2014;7:25-31.
5.
Maung AA, Kaplan LJ. Airway pressure release ventilation in acute respiratory distress syndrome. Crit Care Clin 2011;27:501-9.
6.
Roy S, Sadowitz B, Andrews P, Gatto LA, Marx W, Ge L, et al. Early stabilizing alveolar ventilation prevents acute respiratory distress syndrome: A novel timing-based ventilatory intervention to avert lung injury. J Trauma Acute Care Surg 2012;73:391-400.
7.
Sud S, Sud M, Friedrich JO, Wunsch H, Meade MO, Ferguson ND, et al. High-frequency ventilation versus conventional ventilation for treatment of acute lung injury and acute respiratory distress syndrome. Cochrane Database Syst Rev 2013;2:CD004085.
8.
Ngubane T. Mechanical ventilation and the injured brain. South Afr J Anaesth Analg 2011;17:76-80.
How to cite this article: Mohta M. What’s new in emergencies, trauma and shock? Mechanical ventilation in trauma patients: A tight-rope walk!. J Emerg Trauma Shock 2014;7:1-2. Received: 01.09.13. Accepted: 02.09.13. Source of Support: Nil. Conflict of Interest: None declared.
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“QUICK RESPONSE CODE” LINK FOR FULL TEXT ARTICLES The journal issue has a unique new feature for reaching to the journal’s website without typing a single leƩer. Each arƟcle on its first page has a “Quick Response Code”. Using any mobile or other hand-held device with camera and GPRS/other internet source, one can reach to the full text of that parƟcular arƟcle on the journal’s website. Start a QR-code reading soŌware (see list of free applicaƟons from hƩp://Ɵnyurl.com/yzlh2tc) and point the camera to the QR-code printed in the journal. It will automaƟcally take you to the HTML full text of that arƟcle. One can also use a desktop or laptop with web camera for similar funcƟonality. See hƩp://Ɵnyurl.com/2bw7fn3 or hƩp://Ɵnyurl.com/3ysr3me for the free applicaƟons. 2
Journal of Emergencies, Trauma, and Shock I 7:1 I Jan - Mar 2014
Copyright of Journal of Emergencies, Trauma & Shock is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
What’s new in emergencies, trauma and shock? Mechanical ventilation in trauma patients: A tight-rope walk! Medha Mohta Department of Anaesthesiology and Critical Care, University College of Medical Sciences and GTB Hospital, Delhi, India
A large proportion of trauma patients need mechanical ventilation. They are at a great risk of developing acute lung injury (ALI) and acute respiratory distress syndrome (ARDS).[1] Conditions like pulmonary contusion, shock, multiple transfusions, fractures, aspiration, near drowning, smoke inhalation, and fat embolism predispose trauma patients to development of ARDS. [1] Sometimes mechanical ventilation may be needed in the absence of lung injury, for example, a brain injured patient may require intubation and ventilation for airway protection or for prevention of secondary brain injury. Lung protective ventilation strategy using lower tidal volumes and plateau pressures with high positive end-expiratory pressure (PEEP) and permissive hypercapnia has become widely accepted for management of ALI and ARDS and the same is advocated for the majority of chest trauma patients. This strategy is aimed at preventing ventilator associated lung injury (VALI), which results from high lung volumes (volutrauma), high airway pressures (barotrauma), and repetitive opening and closing of collapsed lung units (atelectrauma). Lung injury can propagate proinflammatory cytokine cascade resulting in biotrauma.[2] All these problems can be avoided by adopting lung protective ventilation. However, the management becomes tricky when lung injury occurs in concurrence with head injury. ARDS develops in up to 20% patients suffering from severe head injury.[3] The ventilatory management goals for lung and brain injury are in conflict with each other. High PEEP and hypercapnia, Address for correspondence: Dr. Medha Mohta, E-mail: [email protected] Access this article online Quick Response Code: Website: www.onlinejets.org
DOI: 10.4103/0974-2700.125630
Journal of Emergencies, Trauma, and Shock I 7:1 I Jan - Mar 2014
major components of lung protective ventilatory strategy, can increase intracranial pressure (ICP) and reduce cerebral perfusion pressure (CPP), thus worsening the brain injury. Therefore one needs to use a very cautious and balanced approach to achieve good outcome in trauma patients. In this issue of JETS,. Arora, et al. have highlighted various ventilatory strategies used in trauma patients.[4] They have described common injuries to different organ systems and their management principles. Independent lung ventilation has an important role in cases of massive chest trauma where isolation of lungs is required. In most of the patients with traumatic injuries of chest, protective lung ventilatory strategy remains the basic principle. Some other ventilatory modes based on open lung concept, for example, airway pressure release ventilation (APRV), high frequency oscillatory ventilation (HFOV), and high frequency percussive ventilation (HFPV) also help in preventing and managing VALI. Extracorporeal membrane oxygenation (ECMO) provides rest to the lungs by facilitating gas exchange outside the body. Other newer techniques like closed loop ventilation seem to have potential for further improving ventilatory management of critically ill patients. APRV appears to be a promising technique that improves lung recruitment, oxygenation, end-organ blood flow, pulmonary vasoconstriction, and sedation requirements.[5] However, any reduction in mortality has not been proven; therefore trials directly comparing APRV with standard lung protective ventilation in ARDS/ALI patients are needed. There have been encouraging results from a recent animal study demonstrating that early application of APRV stabilizes alveoli, reduces alveolar edema, and thus prevents development of ARDS.[6] HFOV has been found to decrease mortality when compared with conventional ventilation. However, it is yet to be seen if it has any advantage over current lung protective ventilatory strategies.[7] Some retrospective studies have shown good results with HFPV in trauma patients having ARDS with or without 1
Mohta: Mechanical ventilation in trauma
head injury. This technique produced significant improvement in oxygenation with reduction in ICP during first 16 hours, when applied in head injured patients with ARDS.[3] However, further trials are required to evaluate the long-term outcome and reduction in mortality, if any. In patients with traumatic brain injury and ALI/ARDS, a strategic ventilatory approach, maintaining a balance between principles for brain injury management and protective lung ventilation is required. High levels of PEEP have a potential to increase intrathoracic pressure, thus decreasing cerebral venous drainage and in turn compromising cerebral perfusion. However, in case of noncompliant lungs, as is the situation in patients with ALI/ARDS, transmission of intrathoracic pressure to cranium and thus effect on cerebral perfusion is lesser.[8] Thus PEEP can be safely applied in this group of patients, provided the volume status and mean arterial pressure are maintained and the level of PEEP provided is lower than ICP.[8] The lowest level of PEEP that maintains oxygenation should be applied. Head elevation with avoidance of extreme neck rotation and tight endotracheal tube ties around the neck are quite helpful. However, arterial carbon dioxide tension plays an important role in determining cerebral blood volume, intracranial compliance, and ICP.[8] Hence hypercapnia should be avoided and all efforts should be made to maintain normocarbia. Thus the outcome of trauma patients can be improved by following principles of ventilatory management according to the organ systems involved. Further studies using newer ventilatory strategies are needed to find optimal solutions to the conflicts faced in polytrauma patients.
REFERENCES 1.
McCunn M, Sutcliffe AJ, Mauritz W, and the ITACCS Critical Care Committee. Guidelines for management of mechanical ventilation in critically injured patients. Available from: http://www.itaccs.com/ traumacare/archive/04_03_Fall_2004/guidelines_for_management.pdf. [Last accessed on 2013 Jul 28].
2.
Ritacca FV, Stewart TE. Clinical review: High-frequency oscillatory ventilation in adults - a review of the literature and practical applications. Crit Care 2003;7:385-90.
3.
Salim A, Miller K, Dangleben D, Cipolle M, Pasquale M. Highfrequency percussive ventilation: An alternative mode of ventilation for head-injured patients with adult respiratory distress syndrome. J Trauma 2004;57:542-6.
4.
Shubhangi Arora, Preet Mohinder Singh, Anjan Trikha. Ventilatory strategies in trauma patients. J Emerg Trauma Shock 2014;7:25-31.
5.
Maung AA, Kaplan LJ. Airway pressure release ventilation in acute respiratory distress syndrome. Crit Care Clin 2011;27:501-9.
6.
Roy S, Sadowitz B, Andrews P, Gatto LA, Marx W, Ge L, et al. Early stabilizing alveolar ventilation prevents acute respiratory distress syndrome: A novel timing-based ventilatory intervention to avert lung injury. J Trauma Acute Care Surg 2012;73:391-400.
7.
Sud S, Sud M, Friedrich JO, Wunsch H, Meade MO, Ferguson ND, et al. High-frequency ventilation versus conventional ventilation for treatment of acute lung injury and acute respiratory distress syndrome. Cochrane Database Syst Rev 2013;2:CD004085.
8.
Ngubane T. Mechanical ventilation and the injured brain. South Afr J Anaesth Analg 2011;17:76-80.
How to cite this article: Mohta M. What’s new in emergencies, trauma and shock? Mechanical ventilation in trauma patients: A tight-rope walk!. J Emerg Trauma Shock 2014;7:1-2. Received: 01.09.13. Accepted: 02.09.13. Source of Support: Nil. Conflict of Interest: None declared.
Announcement
“QUICK RESPONSE CODE” LINK FOR FULL TEXT ARTICLES The journal issue has a unique new feature for reaching to the journal’s website without typing a single leƩer. Each arƟcle on its first page has a “Quick Response Code”. Using any mobile or other hand-held device with camera and GPRS/other internet source, one can reach to the full text of that parƟcular arƟcle on the journal’s website. Start a QR-code reading soŌware (see list of free applicaƟons from hƩp://Ɵnyurl.com/yzlh2tc) and point the camera to the QR-code printed in the journal. It will automaƟcally take you to the HTML full text of that arƟcle. One can also use a desktop or laptop with web camera for similar funcƟonality. See hƩp://Ɵnyurl.com/2bw7fn3 or hƩp://Ɵnyurl.com/3ysr3me for the free applicaƟons. 2
Journal of Emergencies, Trauma, and Shock I 7:1 I Jan - Mar 2014
Copyright of Journal of Emergencies, Trauma & Shock is the property of Medknow Publications & Media Pvt. Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
