see also [[IVDU issues#intra-arterial injection (trash hand)|trash hand]] > [!key points] > - tibial, supracondylar humerus, femoral fractures most common cause > - severe elevation in pressure >8 hours leads to irreversible ischaemic injury (volkmann's contracture) > - leg compartments, extensor and flexor forearm compartments, intrinsic hand muscle compartments at greatest risk > - onset usually 6-24 hours following injury > - *normal* compartment pressure *0-8* mmHg; compartment pressures *20-30* mmHg compromise of capillary blood flow; *≥ 35* absent flow - surgical emergency - usually affects lower leg or forearm in context of fracture - suspect when pain is worsening or out of proportion to injury - usually 6-24 hours post injury ![[Pasted image 20241105153156.png]] **signs** - pain on passive *stretching muscles* passing through affected compartment - pain “out of proportion” to injury - usually throbbing then becomes constant - compression of a muscle in compartment away from injury produces pain - note that distal vascular or neurological compromise are **late signs** and compartment syndrome is NOT excluded by a limb being "neurovascularly intact" - pain is initially *throbbing* then becomes constant → paraesthesia/numbness is a late sign - may have venous congestion earlier in course of syndrome **causes** - tibial fracture - supracondylar humerus - femoral - [[Lis Franc injury]] > Higher risk in muscular individuals eg young males, patients on steroids, or those with coagulopathy **exam** - skin perfusion is almost always normal - pain on passive movement of muscles - pulse ox insufficiently sensitive to be of any use - *compartment pressures* - normal 0-8 mmHg - 20-30 compromise capillary blood flow - \> 35 mmHg absent capillary blood flow > [!doses] Compartment pressure monitoring procedure > - indicated if evidence of ↑ compartment pressure > - infiltrate local anaesthetic into skin and s/c tissue > - insert 18g spinal needle or IV catheter needle into compartment (pushing on muscles in the compartment should case and ↑ in pressure monitored) > - attatch pressure monitor to needle via saline filled IV tubing > - inject 1mL of saline into compartment > - read the compartment pressure **treatment** - fasciotomy # Fasciotomy **indications** - evidence of vascular compression - compartment pressures >30 mmHg - [[rhabdomyolysis]] **technique** - generous incision of the affected compartments - leave wound open and cover with sterile dressings - closed after swelling subsided -- usually ~5 days - prevents most myoneuronal defects when performed < 6 hours of symptom onset # Abdominal compartment syndrome - following abdo surgery for major trauma - normal intra-abdominal pressure is 0 - ==significantly raised pressure is > 25 mmHg== - can monitor pressure via urinary cathether or NGT **Effects** - ↓ urine output - compress IVC → reduced venous return - increased intrathoracic and intracranial pressure **Treatment** - leave abdo covered but not closed after major abdominal trauma surgery ## pneumoperitoneum (anaesthetics) | Physiological | Effect | | ------------------------ | --------- | | Airway pressure | ↑ | | FRC | ↓ | | [[Pulmonary compliance]] | ↓ | | V/Q mismatch | ↑ | | Venous return | ↓ | | SVR | ↑ | | Cardiac output | Same or ↓ | | Arrhythmia risk | ↑ | | Gastric regurg risk | ↑ | | ICP | ↑ | | CPP | ↑ or same | ***Effects of gas insulflation***  - Stretching of the peritoneum may cause vagal stimulation, resulting in sinus bradycardia, nodal rhythm, and occasional asystole. Anticipate and treat with vagolytics, e.g. atropine, glycopyrronium. - Gas insufflation may result in sympathetic response, leading to hypertension and tachycardia. - CO2 is readily absorbed from the peritoneum and may cause hypercapnia and acidosis. - extraperitoneal gas insufflation may occur through a misplaced trocar or insufflation needle, via an anatomical defect (e.g. between the pleura and peritoneum), or when gas under pressure within the abdomen dissects through tissue planes. This may result in SC emphysema, pneumomediastinum, pneumopericardium, or pneumothorax.