A proposed relationship between increased intra-abdominal, intrathoracic, and intracranial pressure

OBJECTIVES

To determine the effect of acutely increased intra-abdominal pressure on pleural pressure, intracranial pressure, and cerebral perfusion pressure, and to clarify the relationship between these parameters.

DESIGN

Nonrandomized, controlled study.

SETTING

Laboratory at a university medical center.

SUBJECTS

Yorkshire swine, weighing 15 to 20 kg.

INTERVENTIONS

Anesthetized, ventilated swine had a balloon inserted into the peritoneal cavity and catheters placed for measurement of intracranial pressure, pleural pressure, central venous pressure, pulmonary artery occlusion pressure, and mean arterial pressure. Following baseline measurements, intra-abdominal pressure was increased by incrementally inflating the intraperitoneal balloon. All parameters were remeasured 30 mins after each increase in intra-abdominal pressure. Two groups were studied: a) group 1 (n = 9) animals had intra-abdominal pressure increased to 25 mm Hg above baseline, then released; b) group 2 (n = 3) animals underwent sternotomy and pleuropericardotomy to prevent an increase in pleural pressure with increasing intra-abdominal pressure.

MEASUREMENTS AND MAIN RESULTS

Increase of intra-abdominal pressure to 25 mm Hg above baseline caused significant (p < .05) increases in intracranial pressure (7.3 +/- 0.6 [SEM] to 16.4 +/- 1.9 mm Hg), pleural pressure (4.3 +/- 1.3 to 11.8 +/- 1.9 mm Hg), pulmonary artery occlusion pressure (9.0 +/- 0.6 to 14.3 +/- 0.8 mm Hg), and central venous pressure (6.6 +/- 0.7 to 10.7 +/- 0.9 mm Hg). The cardiac index (3.4 +/- 0.3 to 1.6 +/- 0.1 L/min/m2) and cerebral perfusion pressure (75.6 +/- 3.6 to 62.0 +/- 6.8 mm Hg) deceased significantly (p < .05), whereas mean arterial pressure (82.8 +/- 3.2 to 78.4 +/- 6.6 mm Hg) remained essentially constant. Sternotomy and pleuro-pericardotomy negated all effects of increased intra-abdominal pressure except the decreased cardiac index (1.6 +/- 0.1 to 2.5 +/- 0.2 L/min/m2).

CONCLUSIONS

Acutely increased intra-abdominal pressure causes a significant increase in intracranial pressure and a decrease in cerebral perfusion pressure. Increased intra-abdominal pressure appears to produce this effect by augmenting pleural and other intrathoracic pressures and causing a functional obstruction to cerebral venous outflow via the jugular venous system. It is possible that the same phenomenon may be why persons with chronically increased intra-abdominal pressure, such as the morbidly obese, suffer from a high frequency rate of idiopathic intracranial hypertension.

Failure of reconstruction of the anterior cruciate ligament due to impingement by the intercondylar roof

The relationship between impingement of the roof of the intercondylar notch on a reconstructed anterior cruciate ligament, and the subsequent stability and range of extension of the joint, was analyzed in forty-seven knees. The extent of the impingement was determined by analysis of the relationship of the tibial tunnel to the intersection of the line of slope of the intercondylar roof with the plane of the subchondral bone of the articular surface of the tibial plateau. These lines were drawn on a lateral roentgenogram that was made with the knee in maximum extension, two years after the operation. In all four knees in which the entire articular opening of the tibial tunnel was anterior to the slope of the intercondylar roof, there was severe impingement on the graft, and all four grafts failed. In the fourteen knees in which a portion of the articular opening of the tibial tunnel was anterior to the slope of the intercondylar roof, there was moderate impingement on the graft, and four grafts failed (an unacceptable rate of failure). There was no impingement in the knees in which the entire articular opening of the tibial tunnel was posterior to the slope of the intercondylar roof, and these knees were associated with the lowest rate of failure of the grafts (three of twenty-nine). Knees that had an impinged graft and regained a complete range of extension became unstable.

Effect of increased renal venous pressure on renal function

OBJECTIVE

Acute renal failure is seen with the acute abdominal compartment syndrome (AACS). Although the cause of acute renal failure in AACS may be multifactorial, renal vein compression alone has not been investigated. This study evaluated the effects of elevated renal vein pressure (RVP) on renal function.

METHODS

Two groups of swine (18-22 kg) were studied after left nephrectomy and placement of a renal artery flow probe to measure renal artery blood flow, renal vein catheter, and ureteral cannula. Two hours were allowed for equilibration and an inulin infusion was begun to calculate inulin clearance for measurement of glomerular filtration rate. Group 1 animals (n = 4) had RVP elevated by 30 mm Hg for 2 hours with renal vein constriction. RVP was then returned to baseline for 1 hour. In group 2 (n = 4), the RVP was not elevated. The cardiac index (2.9 +/- 0.5 L/min/m2) and mean arterial pressure (101 +/- 9 mm Hg) remained stable. Plasma renin activity and serum aldosterone were measured every 60 minutes.

RESULTS

Elevation of RVP (0-30 mm Hg above baseline) in the experimental group showed a significant decrease in renal artery blood flow index (2.7 to 1.5 mL/min per g) and glomerular filtration rate (26 to 8 mL/min) compared with control. In addition, there was significant elevation of plasma serum aldosterone (14 to 25 microng/dL) and plasma renin activity (2.6 to 9.5 microng/mL per h) as well as urinary protein leak in the experimental animals compared with control. These changes were partially or completely reversible as RVP returned toward baseline.

CONCLUSION

Elevated RVP alone leads to decreased renal artery blood flow and glomerular filtration rate and increased plasma renin activity, serum aldosterone, and urinary protein leak. These changes are consistent with the renal pathophysiology seen in AACS, morbid obesity, and preeclampsia. The changes are partially or completely reversed by decreasing renal venous pressure as occurs with abdominal decompression for AACS.

The medial tibial stress syndrome. A cause of shin splints

The medial tibial stress syndrome is a symptom complex seen in athletes who complain of exercise-induced pain along the distal posterior-medial aspect of the tibia. Intramuscular pressures within the posterior compartments of the leg were measured in 12 patients with this disorder. These pressures were not elevated and therefore this syndrome is a not a compartment syndrome. Available information suggests that the medial tibial stress syndrome most likely represents a periostitis at this location of the leg.

Effects of increased intra-abdominal pressure in severe obesity

This article gives an overview, citing animal and clinical studies, of the effects of increased intra-abdominal pressure (IAP) in severe obesity. Animal studies demonstrate that increased IAP increases pleural pressure, cardiac filling pressures, femoral venous pressure, renal venous pressure, systemic blood pressure, and vascular resistance, renin and aldosterone levels, and intracranial pressure. Thus, the comorbidities presumed secondary to increased IAP in obese patients include congestive heart failure, hypoventilation, venous stasis ulcers, gastroesophageal reflux, urinary stress incontinence, incisional hernia, pseudotumor cerebri, proteinuria, and systemic hypertension.

One hundred percent fascial approximation with sequential abdominal closure of the open abdomen

BACKGROUND

Damage-control surgery and the recognition of the abdominal compartment syndrome have improved patient outcomes but at the cost of an open abdomen. Multiple techniques have been introduced to obtain fascial closure for the open abdomen to minimize morbidity and cost of care. We performed a modification of the vacuum-assisted closure (VAC) technique that provided constant fascial tension, hypothesizing this would result in a higher rate of primary fascial closure.

METHODS

After initial temporary closure of the abdomen after post-injury damage control or decompressive laparotomy for abdominal compartment syndrome, we began the sequential closure technique. The technique begins by covering the bowel with the multiple white sponges overlapped like patchwork, and the fascia is placed under moderate tension over the white sponges with #1-PDS sutures. Large black VAC sponges are placed on top of the white sponges and affixed with an occlusive dressing and standard suction tubing is placed. Patients are returned to the operating room for sequential fascial closure and replacement of the sponge sandwich every 2 days, with a resulting decrease in the fascial defect.

RESULTS

Fourteen patients underwent sequential abdominal closure during the study period: 9 owing to damage control surgery and 5 owing to secondary abdominal compartment syndrome. Average time to closure was 7.5 +/- 1.0 days (range 4-16) and average number of laparotomies to closure was 4.6 +/- 0.5 (range 3-8). All patients attained primary fascial closure.

CONCLUSION

We propose a modification of the previously described vacuum-assisted closure technique that achieves 100% fascial approximation in our limited experience. Further application and refinement of this technique may eliminate the need for delayed complex and costly reconstructive abdominal wall procedures for the open abdomen.

Treatment of increasing intracranial pressure secondary to the acute abdominal compartment syndrome in a patient with combined abdominal and head trauma

Acute abdominal compartment syndrome has recently been shown to raise intracranial pressure (ICP). This may increase the risk of ischemic neuronal damage by decreasing cerebral perfusion pressure. We report the successful management of a patient with severe multisystem injury in whom abdominal decompression dramatically reduced high ICP unresponsive to medical measures.

Calcaneal fractures--open reduction and internal fixation (ORIF)

Although pioneers such as Leriche in 1921 [5] and Judet et al in 1954 [4] introduced screw or plate fixation of the broken calcaneus, surgical treatment using open anatomical reduction and stable internal osteosynthesis only commenced at the start of the 1980s. This treatment was made possible by the introduction of new imaging methods such as CT which allowed better detection of the fracture pathology and provided the basis for new surgical strategies. Since the start of the 1990s, various anatomically shaped steel and titanium calcaneal plates have been available. The Foot and Ankle Expert Group of the AO Foundation together with Synthes USA developed an anatomically shaped interlocking calcaneal plate, which has been available in steel since 2002, and a titaniummolybdenum(15%) alloy version (Mathys) since November 2003. The latter is now being tested clinically in our unit.

The morphology of an infarct in nonarteritic anterior ischemic optic neuropathy

OBJECTIVE

The mechanism by which nonarteritic anterior ischemic optic neuropathy (NAION) causes an infarct in the optic nerve is controversial. We studied the three-dimensional anatomic configuration of a NAION infarct to better elucidate its pathophysiology.

DESIGN

Case report with clinicopathologic correlation.

METHODS

Serial sections of the optic nerve from a previously reported patient diagnosed with NAION 20 days before death were studied. Every fourth slide was stained with hematoxylin-eosin, photographed, and digitized. NIH Image 1.62 was used to reconstruct the nerve in all three dimensions, and the infarct morphology was analyzed.

MAIN OUTCOME MEASURES

Morphology of the reconstructed optic nerve infarct.

RESULTS

The area of axonal loss within each section of the optic nerve was identified and reconstructed. The loss was in the superior part of the nerve, encircling the central retinal artery at its greatest extent. Remaining areas of the nerve appeared healthy, and, notably, the periphery of the uninvolved inferior portion of the nerve was normal. Three-dimensional analysis revealed two distinct areas of infarct at the posterior extent of the lesion which coalesced toward the center of the lesion and finally tapered as the infarct reached the optic nerve head. Sagittal reconstructions gave the appearance of a two-pronged fork posteriorly connecting to a single "handle" anteriorly. There was no obvious correlation between the configuration of the infarct and any single vascular territory. The total length of the nerve involved by the infarct was approximately 1.5 mm.

CONCLUSIONS

The morphology of this NAION infarct is not consistent with disease of large or small vessels and, more likely, represents a form of compartment syndrome that causes tissue ischemia.

The medical-legal aspects of compartment syndrome

BACKGROUND

Management of compartment syndrome in the modern era involves not only avoiding the sequelae of a missed diagnosis but also minimizing the risk of a malpractice claim. Little information is available on the legal aspects of compartment syndrome.

METHODS

Twenty-three years of records on closed malpractice claims involving compartment syndrome were reviewed. The data were abstracted from medical records and were analyzed to determine the factors associated with a successful defense.

RESULTS

Nineteen closed claims, involving sixteen patients and encompassing a total liability of 3.8 million USD, were found in the data for malpractice claims closed between 1980 and 2003. Ten claims were resolved in favor of the physician. The average time to closure was 5.5 years. All three claims that went to trial resulted in a verdict for the physician. Evidence of poor physician-patient communication was found in six cases, all of which resulted in an indemnity payment (p < 0.01). Increasing time from the onset of symptoms to the fasciotomy was linearly associated with an increased indemnity payment (p < 0.05). A fasciotomy performed within eight hours after the first presentation of symptoms was uniformly associated with a successful defense.

CONCLUSIONS

While malpractice claims involving compartment syndrome were uncommon, they resulted in a high rate and amount of indemnity payments. Early fasciotomy not only improves patient outcome but is also associated with decreased indemnity risk.

Chronic leg pain in athletes due to a recurrent compartment syndrome

A series of 29 patients, all engaged in sports activity on a regular basis, suffering from recurrent compartmental syndrome, is reported. The syndrome is not restricted only to long distance runners but to athletes involved in a variety of sports activities (soccer, volleyball, cycle racing, gymnastics, judo, physical education, and long distance running). Although most patients presented activity-related leg pain, some patients mainly complained of ankle weakness and recurrent ankle distortions at fatigue. The wick catheter technique proved to be most useful to determine which compartments were involved. The severity of clinical symptoms correlated highly with the anomalies of the tissue pressure measurements. The predominance of deep posterior compartment and multiple compartment involvement are in contrast with most previous reports. Conservative treatment was unsuccessful in every patient, whereas surgical decompression of the involved compartments yielded favorable results in those cases where all the involved compartments were released.

A hypothesis for the cause of complex regional pain syndrome-type I (reflex sympathetic dystrophy): pain due to deep-tissue microvascular pathology

Complex regional pain syndrome-type I (CRPS-I; reflex sympathetic dystrophy) is a chronic pain condition that usually follows a deep-tissue injury such as fracture or sprain. The cause of the pain is unknown. We have developed an animal model (chronic post-ischemia pain) that creates CRPS-I-like symptomatology. The model is produced by occluding the blood flow to one hind paw for 3 hours under general anesthesia. Following reperfusion, the treated hind paw exhibits an initial phase of hyperemia and edema. This is followed by mechano-hyperalgesia, mechano-allodynia, and cold-allodynia that lasted for at least 1 month. Light microscopic analyses and electron microscopic analyses of the nerves at the site of the tourniquet show that the majority of these animals have no sign of injury to myelinated or unmyelinated axons. However, electron microscopy shows that the ischemia-reperfusion injury produces a microvascular injury, slow-flow/no-reflow, in the capillaries of the hind paw muscle and digital nerves. We propose that the slow-flow/no-reflow phenomenon initiates and maintains deep-tissue ischemia and inflammation, leading to the activation of muscle nociceptors, and the ectopic activation of sensory afferent axons due to endoneurial ischemia and inflammation. These data, and a large body of clinical evidence, suggest that in at least a subset of CRPS-I patients, the fundamental cause of the abnormal pain sensations is ischemia and inflammation due to microvascular pathology in deep tissues, leading to a combination of inflammatory and neuropathic pain processes. Moreover, we suggest a unifying idea that relates the pathogenesis of CRPS-I to that of CRPS-II. Lastly, our hypothesis suggests that the role of the sympathetic nervous system in CRPS-I is a factor that is not fundamentally causative, but may have an important contributory role in early-stage disease.

Effects of increased renal parenchymal pressure on renal function

OBJECTIVE

Acute renal failure is seen with the acute abdominal compartment syndrome (AACS). The cause of acute renal failure in AACS is thought to be multifactorial, including increased renal venous pressure, renal parenchymal pressure (RPP), and decreased cardiac output. Previous studies have established the role of renal venous pressure as an important mediator of this renal derangement. In this study, we evaluate the role of renal parenchymal compression on renal function.

METHODS

Two groups of swine (20-26 kg) were studied after left nephrectomy and placement of a renal artery flow probe and ureteral cannula. Two hours were allowed for equilibration, and an inulin infusion was begun to calculate inulin clearance as a measurement of glomerular filtration. In group 1 animals (n = 6), RPP was elevated by 30 mm Hg for 2 hours with renal parenchymal compression. RPP then returned to baseline for 1 hour. In group 2 (n = 6), the RPP was not elevated. The cardiac index, preload, and mean arterial pressure remained stable. Blood samples for plasma renin activity and plasma aldosterone were taken at baseline and at hourly intervals.

RESULTS

Elevation of RPP in the experimental group showed no significant decrease in renal blood flow index or glomerular filtration when compared with control animals. There were no significant elevations of plasma aldosterone or plasma renin activity in the experimental animals when compared with control.

CONCLUSION

Elevated renal compression alone did not create the pathophysiologic derangements seen in AACS. However, prior data from this laboratory found that renal vein compression alone caused a decreased renal blood flow and glomerular filtration and an increased plasma renin activity, plasma aldosterone, and urinary protein leak. These changes are partially or completely reversed by decreasing renal venous pressure as occurs with abdominal decompression for AACS. These data strengthen the proposal that renal vein compression, and not renal parenchymal compression, is the primary mediator of the renal derangements seen in AACS.

Lower leg pain. Diagnosis and treatment of compartment syndromes and other pain syndromes of the leg

Leg pain in athletes has many aetiologies. The clinician must strive to specifically define the clinical problem in order to administer the appropriate treatment for the athlete's condition. Clinical conditions in the leg causing symptoms in athletes include chronic exertional compartment syndrome (CECC), tendinitis, medial tibial stress syndrome, stress fractures, fascial defects, musculotendinous junction disruptions (tennis leg), popliteal artery entrapment syndrome, effort-induced venous thrombosis and nerve entrapment. Appropriate diagnostic studies are needed to allow accurate diagnosis. A work-up might include radiographs, bone scans and compartment pressure measurement. Many of these conditions relate to overuse and training errors. Conservative measures including rest, activity modification and rehabilitation will permit a gradual return to participation in sports. Some problems such as CECC, popliteal artery entrapment syndrome and nerve entrapment may require surgical intervention to allow the resolution of symptoms. Clinicians should be familiar with the range of problems causing leg pain in order to prescribe specific treatment for each athlete.

The relationship between intramuscular pressure of the paraspinal muscles and low back pain

STUDY DESIGN

The relationship between lumbar intramuscular pressure and backache with degenerative lumbar spine diseases was examined. Lumbar intramuscular pressure in 102 patients with low back pain and in 20 normal adults was compared in different positions using Miller's microtip catheter transducer.

OBJECTIVES

This study sought to study the relationship between intramuscular pressure of the lumbar back muscles and degenerative lumbar diseases.

SUMMARY OF BACKGROUND DATA

Measurement of intramuscular pressure is an objective technique for diagnosing lumbar compartment syndrome. The diagnosis of chronic compartment syndrome of the lumbar back muscles is confirmed when an association between an increase in intramuscular pressure and the onset of back pain is established. As spinal alignment changes from lordosis to kyphosis, the intramuscular pressure increases and blood flow decreases.

METHODS

Intramuscular pressure measurements of the lumbar back muscles were performed in various positions and loading. Results in patients with low back pain and in normal adults were compared.

RESULTS

The intramuscular pressure levels were found to be closely related to position and loading. The pattern of changes in pressure depended on the type of disease. The changes in intramuscular pressure in the patients with backache were classified into four distinct patterns. Chronic compartment syndrome of the lumbar back muscles showed two pattern: waxing and plateau.

CONCLUSIONS

Measurement of intramuscular pressure of the lumbar back muscles might be an important method of obtaining a greater knowledge about backache.

Renal arterial resistive index response to intraabdominal hypertension in a porcine model

OBJECTIVE

The abdominal compartment syndrome is a potentially life-threatening condition with frequent renal involvement. There are few if any means of inferring subclinical effects before organ dysfunction. Because intrarenal pressure correlates with renal sonographic indices in other renal diseases, the purpose of this study was to determine the relationship between increasing intraabdominal hypertension and renal vascular flow velocities in a porcine model using renal Doppler ultrasound.

DESIGN

Animal study.

SETTING

University research laboratory.

SUBJECTS

Eight anesthetized, mechanically ventilated, well-hydrated, 30-kg female Yorkshire pigs.

INTERVENTIONS

Intraabdominal hypertension was induced by instillation of warmed intraperitoneal saline through a midline laparoscopic port. Intraabdominal pressure (IAP) was continuously monitored directly from the peritoneum and indirectly from the bladder. IAP was varied from 0 to 50 mm Hg in increments of 5 mm Hg. At each IAP level, gray-scale, color, and spectral Doppler renal arcuate artery ultrasound was obtained and resistive index (RI) and peak airway pressure calculated.

MEASUREMENTS AND MAIN RESULTS

Excellent agreement between direct and indirect IAP was found (bias, 0.032 mm Hg; 95% limits, -5.5 to 5.6 mm Hg). A linear relationship between RI and indirect IAP was observed and was defined by the regression equation: RI = 0.553 + 0.0104 x bladder pressure. There was a trend toward different RIs between left and right kidneys (p = .052) at the same IAP. RI varied in a linear fashion at low peak airway pressure and demonstrated an inflection point with steeper subsequent slope after peak airway pressure of 30 cm H2O. RI values rapidly returned to near baseline after abdominal decompression.

CONCLUSIONS

In this model, the renal artery RI correlated strongly and linearly with the severity of intraabdominal hypertension, making renal Doppler ultrasound a potential noninvasive screening tool for the renal effects of intraabdominal hypertension. Further studies are warranted.

Forearm compartment syndrome in the newborn: report of 24 cases

PURPOSE

Isolated cases of ischemia, compartment syndrome, or Volkmann's ischemic contracture in the forearm of the newborn infant have been reported in the past. The purpose of this study is to review a large series of patients with neonatal forearm compartment syndrome and to report the important clinical features.

METHODS

A search of medical records from 1980 to 2000 identified 24 children with evidence of ischemia of the forearm at the time of birth. Records and images were reviewed for prenatal and birth history, maternal factors, medical conditions, pattern of involvement, treatment, and outcomes. Patients were grouped according to the extent of initial soft-tissue involvement.

RESULTS

All patients presented with a sentinel forearm skin lesion. Patterns of involvement ranged from mild skin and subcutaneous lesions to dorsal and volar compartment syndrome with or without distal tissue loss. Early treatment intervention was limited to a single case in which the diagnosis of compartment syndrome was made and an emergency fasciotomy was performed with a good outcome. In other cases tissue loss, compressive neuropathy, muscle loss, and late skeletal changes were responsible for impaired function. Distal bone growth abnormality was common.

CONCLUSIONS

Forearm compartment syndrome in the newborn is not as uncommon as previously thought. The skin lesion was the common, salient, initial diagnostic finding. Early diagnosis and appropriate referral led to the salvage of a functional limb in 1 of the patients in this series. The severity of the initial insult correlated with the degree of impairment in growth and function. The delayed diagnosis and treatment of an evolving compartment syndrome may compromise further final function.

Chronic compartment syndrome. An unusual cause for claudication

Chronic Compartment Syndrome (CCS) is usually caused by overuse injury in well-conditioned athletes (particularly runners). Less common causes of CCS include blunt trauma, venous insufficiency, and tumor. CCS is clinically manifested as claudication, tightness, and occasional paresthesia. Unlike other forms of overuse injury (tendonitis, stress fracture), CCS does not respond to rest, anti-inflammatory medications, or physical therapy. The diagnosis of this condition is confirmed by elevated compartment pressures (normal less than 15 mmHg; CCS greater than 20 mmHg). The only effective treatment is surgical compartment release. Two hundred nine patients have been surgically treated for CCS, 100 by subcutaneous fasciotomy (group I) and 109 by open fasciectomy (group II). These procedures were usually performed in ambulatory surgery using local anesthesia. Patients treated by open faciectomy instead of subcutaneous fasciotomy had fewer early postoperative wound complications (6% vs. 11%) and fewer late recurrences (2% vs. 11%).

Compartment syndromes and reperfusion injury

Compartment syndrome has been defined as increased pressure within a limited space that compromises the blood supply and function of tissues within that space. The pressure rise is usually a result of increased interstitial fluid, although cell swelling may play a part. Most closed compartment syndromes can be detected by repeated clinical examination. Despite the extensive incisions and dissection required for adequate fasciotomy, if the nerves and muscles can be preserved, the limb will often be relatively normal.

A porcine model of the abdominal compartment syndrome

The purpose of this study was to investigate whether an intra-abdominal pressure (IAP) of 30 mmHg lasting 24 h in a porcine model will lead to a condition comparable with the abdominal compartment syndrome (ACS) in humans. We examined 12 intubated and anesthetized domestic pigs with a mean body weight of 52.5 +/- 4.9 kg. Using a CO2 pneumoperitoneum, the IAP was increased to 30 mmHg (study group, n = 6) for an investigation period of 24 h. In the control group, the IAP remained unchanged. Investigated parameters were cardiac output (CO), peak inspiratory pressure (PIP), urine output (UO), as well as serum alanine aminotransferase (ALT), lactate, lipase, and alkaline phosphatase (AP). Additionally, histopathological examinations were performed. In the study group, CO was significantly reduced compared with the control group. All animals of this group became anuric and their PIP exceeded 40 cm H2O. Furthermore, ALT, AP, lipase, and lactate were significantly increased. Histopathologically, high-grade atelectasis in the lower lobes of the lung together with medium grade liver necrosis, medium grade proximal tubular epithelial necrosis, and medium grade mucosal bowel damage were observed. In this porcine model, an intra-abdominal pressure of 30 mmHg led to a condition comparable with the ACS. Because function or integrity of additional organ systems was impaired, an IAP of 30 mmHg has to be considered a predisposition for the multi-organ dysfunction syndrome in this porcine model.

Calcific myonecrosis: keys to early recognition

Calcific myonecrosis is a rare, late sequela of trauma occurring almost exclusively in the lower extremity which may be confused with an aggressive primary neoplasm. The platelike mineralization pattern seen on radiographs is characteristic but not widely recognized by clinicians. Three cases of calcific myonecrosis are reported, unique in that two presented for care following infection and that one had extended to involve the muscle compartments of the foot, a previously unreported site.