Oxygen Embolism During Surgical Lavage of Chronic Osteomyelitis of Femur with Hydrogen Peroxide

Hydrogen peroxide, an over the counter irrigation solution used in infected and dirty wounds, has been reported mainly in the anesthesia literature to have life threatening complications. We report a case of near fatal gas embolism during an orthopedic procedure of irrigating the wound of a 30 year old female with chronic osteomyelitis of the femur using hydrogen peroxide solution.


INTRODUCTION
Hydrogen peroxide is a commonly used antiseptic solution for cleansing and dressing infected, dirty and contaminated wounds and also abscesses.Hydrogen peroxide promptly breaks down into water and oxygen by the enzymatic action of catalase present in the tissues and blood. 1,2Despite this apparently host friendly mechanism of action, H 2 O 2 has been implicated in several fatal and near-fatal complications. 3,4H 2 O 2 , especially when forcefully injected inside an enclosed wound space results in formation of Þ rst; the nascent oxygen and subsequently; molecular oxygen which cause either venous or arterial embolism. 3We report a case of venous oxygen embolism during an orthopedic surgical lavage of the wound of chronic osteomyelitis of femur.

CASE REPORT
A previously healthy 30 year old female had sustained fracture of shaft of right femur and had undergone Kuntscher nailing at some other center nine months back.She was admitted at our Hospital with the diagnosis of chronic osteomyelitis with discharging sinus over the greater trochanter and abscess on the lateral aspect of distal thigh.She had infective nonunion of the femur and K-nail was in situ.Her initial laboratory Þ ndings showed the total white cell count to be 31200 with 92 % neutrophils and ESR to be 45 mm per hour.She was initially managed with intravenous antibiotics and supportive care after draining of around 100 ml of pus with stab incision on the distal thigh.After 7 days of admission, she underwent an uneventful debridement with irrigation and exchange nailing.Postoperatively, she was doing well till the Þ fth day when pus re-collection was noted in the wound on the lateral aspect of the distal thigh.Also, purulent discharge re-appeared at the entry portal of the nail proximally.Daily dressings were done.
One month after the day of exchange nailing, after repeating her pre-operative routine laboratory tests (which were in normal range), she was taken for debridment and irrigation of the wound.
Intravenous preloading was done and under all aseptic and antiseptic precautions, sub-arachnoid block was performed by the anesthetist with 2.8 ml of 0.5% Bupivacaine (Heavy) using 25G Quinke's needle at the level between L3-L4 vertebra in sitting position.Unilateral block of the right lower limb was achieved and patient was re-positioned for surgical procedure.
Surgical irrigation with betadine and normal saline was begun.After around half an hour from the time of sub-arachnoid block, nearly 100 ml of 3 % hydrogen peroxide was added to the normal saline solution (nearly 50:50 dilution) and pushed into the wound with a 20ml syringe.On the third forceful irrigation of solution into the wound, there was increased bubbling N OA J J uly -D e c e m be r 2 01 3| Vol 3| Iss ue 2 sound of effervescence and the patient immediately began complaining of heaviness around the chest.The heart rate and blood pressure dropped.Injection Atropine 0.6 mg and adrenaline 1.8mg (1:10000) IV was given.By then, there was cardiopulmonary arrest and EKG monitor showed asystole.Immediate airway was maintained with endotracheal intubation and chest compression was started.Injection Adrenaline one ampoule IV repeated.Total 5 cycles of CPR were done.Heart beat reverted and BP was recordable.Injection hydrocortisone 200mg IV stat was given.BP was maintained with ß uids and vasopressors.Senior anesthetist attempted opening CVP lines Þ rst on the right and then on the left side.Gas bubbles oozed from the CVP line on the right side but placement was not conÞ rmed.So, central line was inserted on the left femoral vein.The patient was shifted to the ICU and put on a mechanical ventilation with CMV mode with FiO2=100.The patient had multiple episodes of partial seizures and anticonvulsant was started with neuromedicine consultation ABG done in the ICU showed PH 7.346, PCO2 24.4 mmHg, PaO2 464.7 mmHg, HCO3 13.5 mmol/L and cardiac enzymes ordered were negative.Chest radiograph and EKG showed no signiÞ cant abnormality.
CMV mode was changed to SIMV mode on the second post-op day.Nutritional support with nasogastric tube was started on the third day.Intubation was converted to tracheostomy on the fourth post op day and SIMV was continued.She had upper motor neuron lesion signs and had purposeless eye blinking.This neuro-vegetative state is harbinger of grave prognosis.She is on constant medical review with no signiÞ cant improvement in neurology.

DISCUSSION
H2O2 is a colorless and clear solution .It is an unstable compound and decomposes on prolonged keeping.This decomposition is rapid when in direct contact with biological materials such as blood or tissues as they contain an enzyme, catalase which catalyzes the decomposition of H 2 O 2 into water and oxygen. 5ml of a 3% H 2 O 2 solution will yield 10 ml of oxygen gas in tissue when it decomposes.5 This gas when enters the circulation may cause severe gas embolism.However, the exact mechanism of embolism has been in controversy. Oe study concluded that oxygen molecules formed outside the vessels further diffuse into the vascular bed.14 But another study suggested that oxygen formed inside the vessels cause the embolism as H 2 O 2 has higher diffusing capacity that the molecular oxygen itself.15 In our case, the 60 ml of diluted (50:50) solution contained nearly 30 ml of 3% H 2 O 2 which in effect produces 300ml of oxygen.
Several literatures report sudden cardiopulmonary collapse after H 2 O 2 administration.Loeb reported severe oxygen embolism after wound irrigation with H2O2 of a large thigh trauma. 3Shukrimu reported venous gas embolism after use of hydrogen peroxide irrigation of a chronic osteomyelitis lesion of the humerus. 6Ouerghi et al reported two case of gas embolism following use of H 2 O 2 after cystectomy of hydatid cysts. 7Despond noted oxygen venous embolism with H 2 O 2 use in post discectomy wound and discouraged the use of it. 8Vidil et al reported a severe oxygen embolism after wound irrigation under pressure with hydrogen peroxide into a closed or partially closed cavity. 9Beattie has reported cardiac arrest following H 2 O 2 irrigation in breast wound and questioned the relative advantage of it for decontamination. 10In the present case, although a transoesophageal echocardiography or precordial Doppler was not used to exactly diagnose gas embolism, the air bubbles gushing out after inserting the central venous line needle on the right side and also the timing of the symptoms and clinical presentation, such as hypotension, bradycardia and Þ nally arrest occurring abruptly after H 2 O 2 forceful lavage in the semi enclosed wound on the thigh, strongly suggest the diagnosis of a gas embolism.This case clearly demonstrates that H 2 O 2 application is not danger free.
The treatment of air embolism is challenging.Various supportive and preventive modalities like Trendelenburg positioning, hyperbaric oxygenation, military antishock trousers (MAST), positive endexpiratory ventilation, avoidance of nitrous oxide and use of steroids and mannitol have been put forward. 11,12,13he easiest method is to avoid the use of the potential culprit of air embolism; the hydrogen peroxide itself. 8

CONCLUSION
The routine use of hydrogen peroxide should be avoided.The use of hydrogen peroxide should be restricted or abandoned especially when the risk outweighs the beneÞ t.