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Intra-abdominal pressure monitoring
Intra-abdominal Pressure Monitoring Renae Stafford, MD
ntra-abdominal pressure (IAP) is measured to assess a patient for the presence of intra-abdominal hypertension (IAH). IAH may occur in many clinical scenarios: large volume resuscitation leading to edema of the bowel wall, accumulation of blood within the peritoneal cavity, large retroperitoneal hematomas, and abdominal operations complicated by postoperative bleeding or bowel wall edema.1 Medical conditions such as acute renal failure, tense ascites, severe pancreatitis, and retroperitoneal
I
tumors can also cause IAH.2,3 IAH has abdominal and systemic effects that may lead to organ dysfunction and failure known as abdominal compartment syndrome (ACS).3,4 ACS is characterized by elevated intra-abdominal and peak airway pressures, inadequate ventilation, abnormal renal function, cardiovascular and splanchnic compromise and increases in intracranial pressure.2-5 These abnormalities are improved after abdominal decompression.3
TECHNIQUE
1
IAP can be measured directly by placing a catheter into the peritoneal cavity and connecting it to a saline manometer or pressure transducer.2,3 This type of measurement is used during abdominal laparoscopic procedures. A more invasive direct measurement involves the placement of a catheter directly into the vena cava.2 Indirect pressure monitoring, which utilizes pressure measurements that are recorded in abdominal organs such as the stomach and bladder, has largely replaced direct measurement in the intensive care unit (ICU). Both of these methods are predicated on the fact that the stomach or bladder are intra-abdominal organs that can be distended and compressed making them subject to the transmission of intra-abdominal pressure.2,3
From the Medical College of Wisconsin, Milwaukee, WI. Address reprint requests to Dr. John A. Weigelt, Division of Trauma/Critical Care, 9200 W. Wisconsin, Milwaukee, WI 53226. © 2003 Elsevier Inc. All rights reserved. 1524-153X/03/0503-0151$30.00/0
Intra-abdominal Pressure Monitoring
2
167
Intragastric pressure is measured by attaching a nasogastric or gastrostomy tube to a saline manometer or a pressure transducer.2,3 In this method, 50 to 100 mL of saline is instilled into the stomach via the nasogastric or gastrostomy tube. The manometer or transducer is zeroed at the mid-axillary line and the pressure is measured at end-expiration.
168
Renae Stafford
3
The most commonly used method for estimating IAP in the ICU is bladder pressure measurement. This technique was first described in 19846 and subsequently validated in animal studies in 1987.7 An indwelling urinary catheter, pressure bag and transducer, normal saline, clamp, three-way stopcock, 18 gauge straight or Huber needle, and 60 mL syringe are required. The transducer is attached to the monitor and the three-way stopcock. The system is then flushed with normal saline and zeroed at the level of the top of the symphysis pubis. The needle is attached to the three-way stopcock and inserted into the aspiration port of the catheter. The third port of the stopcock is attached to a 60 mL syringe. The clamp is applied distal to the aspiration port and 50 to 100 mL of normal saline is instilled into the bladder via the syringe and stopcock. The mean pressure is measured on the monitor. The pressure can also be measured by raising the catheter above the level of the patient allowing a U-shaped loop to form. The height of the fluid column in the catheter can then be measured from the meniscus to the symphysis pubis.2 Care should be taken to remember to remove the clamp from the catheter at the end of the procedure. One must also note that IAP can be falsely elevated in the agitated patient.
INTRA-ABDOMINAL PRESSURE MONITORING The measurement of IAP can be done by two methods and is recorded in either mmHg or cm H20.
INTRA-ABDOMINAL HYPERTENSION AND ABDOMINAL COMPARTMENT SYNDROME The development of IAH and ACS occurs in a graded manner.2 Venous return and splanchnic perfusion may be impaired at 15 mmHg and oliguria is usually seen at
contractility and anuria is apparent at pressures of 30 mmHg. The patient typically has a tensely distended abdomen on physical examination. While treatment for ACS has been advocated on the basis of a grading system that relies primarily on pressure measurement,4 there is no clear consensus about the level of IAH which requires treatment.3 Pusajo and co-workers found significant organ dysfunction with IAP as low as 10 mmHg (13.6 cm H20)8 while others use an IAP of 30 cm H20 (22 mmHg) as a critical level requiring therapy.9 Ivatury and co-workers consider a persistent elevation of IAP beyond 20 to 25 cm H20 as IAH and institute therapy.3 In general, the
Intra-abdominal Pressure Monitoring
when making a decision about treatment for IAH or ACS. The practitioner must also consider the clinical status of the patient at the time the measurements are made. Sequential measurements of IAP may be helpful. A rising IAP in the face of pulmonary, renal, and cardiovascular compromise should prompt the practitioner to consider decompressive laparotomy.10
REFERENCES 1. Chen RJ, Fang JF, Chen MF: Intra-abdominal pressure monitoring as a guideline in the nonoperative management of blunt hepatic trauma. J Trauma 51:44-50, 2001 2. Asensio JA, Ceballos J, Forno W, et al: Intra-abdominal pressure monitoring. In WC Shoemaker, GC Velhamos, D Demetriades (Eds): Procedures and monitoring for the critically ill. Philadelphia: WB Saunders, 2002, pp 99-103 3. Ivatury RR, Diebel L, Porter JM, et al: Intra-abdominal hypertension and the abdominal compartment syndrome. Surg Clin North Am 77:783-800, 1997
169 4. Burch JM, Moore EE, Moore FA, et al: The abdominal compartment syndrome. Surg Clin North Am 76:833, 1996 5. Bloomfield GL, Dalton JM, Sugerman HJ, et al: Treatment of increasing intracranial pressure secondary to acute abdominal compartment syndrome in a patient with combined abdominal and head trauma. J Trauma 39:1168, 1995 6. Kron IL, Harman PK, Nolan SP: The measurement of intraabdominal pressure as a criterion for exploration. Ann Surg 199:28, 1984 7. Iberti TJ, Kelly KM, Gentili DR, et al: A simple technique to accurately determine intra-abdominal pressure. Crit Care Med 15:1140, 1987 8. Pusajo JF, Bumaschny E, Agurrola A, et al: Post-operative intraabdominal pressure: Its relation to splanchnic perfusion, sepsis, multiple organ failure and surgical reintervention. Inten Crit Care Dig 13:2, 1994 9. Widergreen JT, Battisella FD: The open abdomen treatment for abdominal compartment syndrome. J Trauma 37:158, 1994 10. Morken J, West MA: Abdominal compartment syndrome in the intensive care unit. Curr Opin Crit Care 7:268-274, 2001 11. Ivatury RR, Porter JM, Simon RJ, et al: Intra-abdominal hypertension after life-threatening penetrating abdominal trauma: Prophylaxis, incidence and clinical relevance to gastric mucosal pH and abdominal compartment syndrome. J Trauma 44:1016-1023
ntra-abdominal pressure (IAP) is measured to assess a patient for the presence of intra-abdominal hypertension (IAH). IAH may occur in many clinical scenarios: large volume resuscitation leading to edema of the bowel wall, accumulation of blood within the peritoneal cavity, large retroperitoneal hematomas, and abdominal operations complicated by postoperative bleeding or bowel wall edema.1 Medical conditions such as acute renal failure, tense ascites, severe pancreatitis, and retroperitoneal
I
tumors can also cause IAH.2,3 IAH has abdominal and systemic effects that may lead to organ dysfunction and failure known as abdominal compartment syndrome (ACS).3,4 ACS is characterized by elevated intra-abdominal and peak airway pressures, inadequate ventilation, abnormal renal function, cardiovascular and splanchnic compromise and increases in intracranial pressure.2-5 These abnormalities are improved after abdominal decompression.3
TECHNIQUE
1
IAP can be measured directly by placing a catheter into the peritoneal cavity and connecting it to a saline manometer or pressure transducer.2,3 This type of measurement is used during abdominal laparoscopic procedures. A more invasive direct measurement involves the placement of a catheter directly into the vena cava.2 Indirect pressure monitoring, which utilizes pressure measurements that are recorded in abdominal organs such as the stomach and bladder, has largely replaced direct measurement in the intensive care unit (ICU). Both of these methods are predicated on the fact that the stomach or bladder are intra-abdominal organs that can be distended and compressed making them subject to the transmission of intra-abdominal pressure.2,3
From the Medical College of Wisconsin, Milwaukee, WI. Address reprint requests to Dr. John A. Weigelt, Division of Trauma/Critical Care, 9200 W. Wisconsin, Milwaukee, WI 53226. © 2003 Elsevier Inc. All rights reserved. 1524-153X/03/0503-0151$30.00/0
Intra-abdominal Pressure Monitoring
2
167
Intragastric pressure is measured by attaching a nasogastric or gastrostomy tube to a saline manometer or a pressure transducer.2,3 In this method, 50 to 100 mL of saline is instilled into the stomach via the nasogastric or gastrostomy tube. The manometer or transducer is zeroed at the mid-axillary line and the pressure is measured at end-expiration.
168
Renae Stafford
3
The most commonly used method for estimating IAP in the ICU is bladder pressure measurement. This technique was first described in 19846 and subsequently validated in animal studies in 1987.7 An indwelling urinary catheter, pressure bag and transducer, normal saline, clamp, three-way stopcock, 18 gauge straight or Huber needle, and 60 mL syringe are required. The transducer is attached to the monitor and the three-way stopcock. The system is then flushed with normal saline and zeroed at the level of the top of the symphysis pubis. The needle is attached to the three-way stopcock and inserted into the aspiration port of the catheter. The third port of the stopcock is attached to a 60 mL syringe. The clamp is applied distal to the aspiration port and 50 to 100 mL of normal saline is instilled into the bladder via the syringe and stopcock. The mean pressure is measured on the monitor. The pressure can also be measured by raising the catheter above the level of the patient allowing a U-shaped loop to form. The height of the fluid column in the catheter can then be measured from the meniscus to the symphysis pubis.2 Care should be taken to remember to remove the clamp from the catheter at the end of the procedure. One must also note that IAP can be falsely elevated in the agitated patient.
INTRA-ABDOMINAL PRESSURE MONITORING The measurement of IAP can be done by two methods and is recorded in either mmHg or cm H20.
INTRA-ABDOMINAL HYPERTENSION AND ABDOMINAL COMPARTMENT SYNDROME The development of IAH and ACS occurs in a graded manner.2 Venous return and splanchnic perfusion may be impaired at 15 mmHg and oliguria is usually seen at
contractility and anuria is apparent at pressures of 30 mmHg. The patient typically has a tensely distended abdomen on physical examination. While treatment for ACS has been advocated on the basis of a grading system that relies primarily on pressure measurement,4 there is no clear consensus about the level of IAH which requires treatment.3 Pusajo and co-workers found significant organ dysfunction with IAP as low as 10 mmHg (13.6 cm H20)8 while others use an IAP of 30 cm H20 (22 mmHg) as a critical level requiring therapy.9 Ivatury and co-workers consider a persistent elevation of IAP beyond 20 to 25 cm H20 as IAH and institute therapy.3 In general, the
Intra-abdominal Pressure Monitoring
when making a decision about treatment for IAH or ACS. The practitioner must also consider the clinical status of the patient at the time the measurements are made. Sequential measurements of IAP may be helpful. A rising IAP in the face of pulmonary, renal, and cardiovascular compromise should prompt the practitioner to consider decompressive laparotomy.10
REFERENCES 1. Chen RJ, Fang JF, Chen MF: Intra-abdominal pressure monitoring as a guideline in the nonoperative management of blunt hepatic trauma. J Trauma 51:44-50, 2001 2. Asensio JA, Ceballos J, Forno W, et al: Intra-abdominal pressure monitoring. In WC Shoemaker, GC Velhamos, D Demetriades (Eds): Procedures and monitoring for the critically ill. Philadelphia: WB Saunders, 2002, pp 99-103 3. Ivatury RR, Diebel L, Porter JM, et al: Intra-abdominal hypertension and the abdominal compartment syndrome. Surg Clin North Am 77:783-800, 1997
169 4. Burch JM, Moore EE, Moore FA, et al: The abdominal compartment syndrome. Surg Clin North Am 76:833, 1996 5. Bloomfield GL, Dalton JM, Sugerman HJ, et al: Treatment of increasing intracranial pressure secondary to acute abdominal compartment syndrome in a patient with combined abdominal and head trauma. J Trauma 39:1168, 1995 6. Kron IL, Harman PK, Nolan SP: The measurement of intraabdominal pressure as a criterion for exploration. Ann Surg 199:28, 1984 7. Iberti TJ, Kelly KM, Gentili DR, et al: A simple technique to accurately determine intra-abdominal pressure. Crit Care Med 15:1140, 1987 8. Pusajo JF, Bumaschny E, Agurrola A, et al: Post-operative intraabdominal pressure: Its relation to splanchnic perfusion, sepsis, multiple organ failure and surgical reintervention. Inten Crit Care Dig 13:2, 1994 9. Widergreen JT, Battisella FD: The open abdomen treatment for abdominal compartment syndrome. J Trauma 37:158, 1994 10. Morken J, West MA: Abdominal compartment syndrome in the intensive care unit. Curr Opin Crit Care 7:268-274, 2001 11. Ivatury RR, Porter JM, Simon RJ, et al: Intra-abdominal hypertension after life-threatening penetrating abdominal trauma: Prophylaxis, incidence and clinical relevance to gastric mucosal pH and abdominal compartment syndrome. J Trauma 44:1016-1023