- Email: [email protected]
Assessment of Intra-Abdominal Pressure by Measurement of Abdominal Wall Tension
Journal of Surgical Research 166, 70–72 (2011) doi:10.1016/j.jss.2010.03.010
COMMENTARY Assessment of Intra-Abdominal Pressure by Measurement of Abdominal Wall Tension Submitted for publication February 26, 2010
In this study [1], the authors assess the relationship between intraabdominal pressure (IAP) and abdominal wall tension (AWT) in fresh human corpses using a prototype noninvasive force and distance sensor attached to a hand held personal digital assistant. They demonstrate that changes in IAP lead to changes in AWT, and that changes in AWT differ between points across the abdominal surface. Additionally they measured AWT in healthy volunteers and showed that AWT changes in response to maneuvers known to change IAP, respiration, position, and that AWT differs between the genders. This correlation offers an interesting potential for a simple, noninvasive means of assessing IAP. The authors theorize that their device could be useful for screening and monitoring patients at risk for intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). Markedly increased IAP is termed intra-abdominal hypertension (IAH), which has profound effects on both local and systemic tissues and organ systems which, if untreated, can lead to lethal organ failure. The clinical condition that results from the organ dysfunction that occurs with IAH is termed abdominal compartment syndrome (ACS). If untreated, ACS can be rapidly fatal, making early identification imperative. The exact level of IAP that causes end organ dysfunction is not known [2]. The detrimental physiologic effects of IAH likely take place before the manifestations of ACS become clinically evident [3]. Decreases in splanchnic blood flow have been noted with intra-abdominal pressures as low as 10 mmHg [4]. In a dog model, Richards et al. showed that oliguria occurred when IAP reached 15–20 mmHg, and anuria occurred when IAP exceeded 20 mmHg [5]. In the current study, IAP was generated and measured in cadavers by air insufflation with a laparoscopic device in increments of 5 mmHg from 5 mmHg to 20 mmHg. While a linear relationship was found over this range of interest, the slope of that line differed greatly between subjects and at different anatomic locations within the same subject. As the authors note, this results in the inability to diagnose the resulting IAP by a single measurement of AWT. Whether AWT correlates with the clinically relevant measures of IAP in critically ill patients or predicts ACS was not assessed in this study. Techniques for measurement of IAP have been described for intragastric, intracolonic, intravesical, and inferior vena cava catheters [6]. These methods all depend on the IAP being transmitted across the wall of the viscous organ or vascular structure, which can then be transduced. The most
0022-4804/$36.00 Ó 2011 Elsevier Inc. All rights reserved.
70
HAVENS AND SOYBEL: ASSESSMENT OF INTRA-ABDOMINAL PRESSURE
common organ used for transduced pressures is the bladder; however bladder pressure may be inaccurate in the setting of intraperitoneal adhesions, pelvic hematomas or fractures, abdominal packs, or neurogenic bladder [6, 7]. This makes alternative means of measurement of IAP, or a surrogate such as AWT, clinically advantageous. In the current study, bladder pressure was not measured. The authors correctly note that further studies comparing AWT to bladder pressure are needed. Interestingly, the current study did not find a correlation between body mass index (BMI) and AWT. IAP has been shown to positively correlate with BMI in several studies [8, 9]. Sanchez et al. measured intravesicular pressure in 77 hospitalized patients and, using multiple regression analysis, found only BMI and abdominal surgery were positively correlated with IAP [10]. As the authors note that their study may not have included a wide enough range of BMI to demonstrate this correlation. As BMI increases, the distance between the skin and abdominal fascia also increases, which may exceed the limits of the measuring device used by the authors. Further studies over a wider range of BMI will be necessary to clarify this. Many patients at risk for IAH go undiagnosed [11]. Current strategies for assessment of IAP have limitations. The development of a simple, noninvasive means of assessing IAP may improve screening for IAH. The current study is an engaging first step in this process, but further clinical validation is necessary. Joaquim M. Havens, M.D. Division of Trauma, Burns, and Surgical Critical Care Department of Surgery Brigham and Women’s Hospital 75 Francis Street Boston, MA 02115 E-mail: [email protected]
David I. Soybel, M.D. Division of General and Gastrointestinal Surgery Department of Surgery Brigham and Women’s Hospital 75 Francis Street Boston, MA 02115 E-mail: [email protected]
REFERENCES 1. van Ramshorst GH, Salih M, Hop WCJ, et al. Noninvasive assessment of intra-abdominal pressure by measurement of abdominal wall tension. J Surg Res 2010, in press. 2. Burch JM, Moore EE, Moore FA, et al. The abdominal compartment syndrome. Surg Clin North Am 1996;76:833. 3. Schein M, Ivatury R. Intra-abdominal hypertension and the abdominal compartment syndrome. Br J Surg 1998;85:1027. 4. Friedlander MH, Simon RJ, Ivatury R, et al. Effect of hemorrhage on superior mesenteric artery flow during increased intra-abdominal pressures. J Trauma 1998;45:433. 5. Richards WO, Scovill W, Shin B, et al. Acute renal failure associated with increased abdominal pressure. Ann Surg 1983;1977:183. 6. Malbrain ML. Different techniques to measure intra-abdominal pressure (IAP): Time for a critical reappraisal. Intensive Care Med 2004;30:357. 7. Lacey SR, Bruce J, Brooks SP, et al. The relative merits of various methods of indirect measurement of intraabdominal pressure as a guide to closure of abdominal wall defects. J Pediatr Surg 1987;22:1207. 8. Cobb WS, Burns JM, Kercher KW, et al. Normal intra-abdominal pressure in health adults. J Surg Res 2005;129:23.
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JOURNAL OF SURGICAL RESEARCH: VOL. 166, NO. 1, MARCH 2011 9. Sugerman H, Windsor A, Bessos M, et al. Intra-abdominal pressure, sagittal abdominal diameter, and obesity comorbidity. J Intern Med 1997;241:71. 10. Sanchez N, Tenofsky P, Dort H, et al. What is normal intra-abdominal pressure? Am Surg 2001;67:243. 11. Ravishankar N, Hunter J. Measurement of intra-abdominal pressure in intensive care units in the United Kingdom: a national postal questionnaire study. Br J Anaesth 2005;94:763.
COMMENTARY Assessment of Intra-Abdominal Pressure by Measurement of Abdominal Wall Tension Submitted for publication February 26, 2010
In this study [1], the authors assess the relationship between intraabdominal pressure (IAP) and abdominal wall tension (AWT) in fresh human corpses using a prototype noninvasive force and distance sensor attached to a hand held personal digital assistant. They demonstrate that changes in IAP lead to changes in AWT, and that changes in AWT differ between points across the abdominal surface. Additionally they measured AWT in healthy volunteers and showed that AWT changes in response to maneuvers known to change IAP, respiration, position, and that AWT differs between the genders. This correlation offers an interesting potential for a simple, noninvasive means of assessing IAP. The authors theorize that their device could be useful for screening and monitoring patients at risk for intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). Markedly increased IAP is termed intra-abdominal hypertension (IAH), which has profound effects on both local and systemic tissues and organ systems which, if untreated, can lead to lethal organ failure. The clinical condition that results from the organ dysfunction that occurs with IAH is termed abdominal compartment syndrome (ACS). If untreated, ACS can be rapidly fatal, making early identification imperative. The exact level of IAP that causes end organ dysfunction is not known [2]. The detrimental physiologic effects of IAH likely take place before the manifestations of ACS become clinically evident [3]. Decreases in splanchnic blood flow have been noted with intra-abdominal pressures as low as 10 mmHg [4]. In a dog model, Richards et al. showed that oliguria occurred when IAP reached 15–20 mmHg, and anuria occurred when IAP exceeded 20 mmHg [5]. In the current study, IAP was generated and measured in cadavers by air insufflation with a laparoscopic device in increments of 5 mmHg from 5 mmHg to 20 mmHg. While a linear relationship was found over this range of interest, the slope of that line differed greatly between subjects and at different anatomic locations within the same subject. As the authors note, this results in the inability to diagnose the resulting IAP by a single measurement of AWT. Whether AWT correlates with the clinically relevant measures of IAP in critically ill patients or predicts ACS was not assessed in this study. Techniques for measurement of IAP have been described for intragastric, intracolonic, intravesical, and inferior vena cava catheters [6]. These methods all depend on the IAP being transmitted across the wall of the viscous organ or vascular structure, which can then be transduced. The most
0022-4804/$36.00 Ó 2011 Elsevier Inc. All rights reserved.
70
HAVENS AND SOYBEL: ASSESSMENT OF INTRA-ABDOMINAL PRESSURE
common organ used for transduced pressures is the bladder; however bladder pressure may be inaccurate in the setting of intraperitoneal adhesions, pelvic hematomas or fractures, abdominal packs, or neurogenic bladder [6, 7]. This makes alternative means of measurement of IAP, or a surrogate such as AWT, clinically advantageous. In the current study, bladder pressure was not measured. The authors correctly note that further studies comparing AWT to bladder pressure are needed. Interestingly, the current study did not find a correlation between body mass index (BMI) and AWT. IAP has been shown to positively correlate with BMI in several studies [8, 9]. Sanchez et al. measured intravesicular pressure in 77 hospitalized patients and, using multiple regression analysis, found only BMI and abdominal surgery were positively correlated with IAP [10]. As the authors note that their study may not have included a wide enough range of BMI to demonstrate this correlation. As BMI increases, the distance between the skin and abdominal fascia also increases, which may exceed the limits of the measuring device used by the authors. Further studies over a wider range of BMI will be necessary to clarify this. Many patients at risk for IAH go undiagnosed [11]. Current strategies for assessment of IAP have limitations. The development of a simple, noninvasive means of assessing IAP may improve screening for IAH. The current study is an engaging first step in this process, but further clinical validation is necessary. Joaquim M. Havens, M.D. Division of Trauma, Burns, and Surgical Critical Care Department of Surgery Brigham and Women’s Hospital 75 Francis Street Boston, MA 02115 E-mail: [email protected]
David I. Soybel, M.D. Division of General and Gastrointestinal Surgery Department of Surgery Brigham and Women’s Hospital 75 Francis Street Boston, MA 02115 E-mail: [email protected]
REFERENCES 1. van Ramshorst GH, Salih M, Hop WCJ, et al. Noninvasive assessment of intra-abdominal pressure by measurement of abdominal wall tension. J Surg Res 2010, in press. 2. Burch JM, Moore EE, Moore FA, et al. The abdominal compartment syndrome. Surg Clin North Am 1996;76:833. 3. Schein M, Ivatury R. Intra-abdominal hypertension and the abdominal compartment syndrome. Br J Surg 1998;85:1027. 4. Friedlander MH, Simon RJ, Ivatury R, et al. Effect of hemorrhage on superior mesenteric artery flow during increased intra-abdominal pressures. J Trauma 1998;45:433. 5. Richards WO, Scovill W, Shin B, et al. Acute renal failure associated with increased abdominal pressure. Ann Surg 1983;1977:183. 6. Malbrain ML. Different techniques to measure intra-abdominal pressure (IAP): Time for a critical reappraisal. Intensive Care Med 2004;30:357. 7. Lacey SR, Bruce J, Brooks SP, et al. The relative merits of various methods of indirect measurement of intraabdominal pressure as a guide to closure of abdominal wall defects. J Pediatr Surg 1987;22:1207. 8. Cobb WS, Burns JM, Kercher KW, et al. Normal intra-abdominal pressure in health adults. J Surg Res 2005;129:23.
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JOURNAL OF SURGICAL RESEARCH: VOL. 166, NO. 1, MARCH 2011 9. Sugerman H, Windsor A, Bessos M, et al. Intra-abdominal pressure, sagittal abdominal diameter, and obesity comorbidity. J Intern Med 1997;241:71. 10. Sanchez N, Tenofsky P, Dort H, et al. What is normal intra-abdominal pressure? Am Surg 2001;67:243. 11. Ravishankar N, Hunter J. Measurement of intra-abdominal pressure in intensive care units in the United Kingdom: a national postal questionnaire study. Br J Anaesth 2005;94:763.