This is a study of the venous gangrene of lower extremities and Staphylococcus aureus sepsis. We report on a premature infant who developed phlegmasia cerulea dolens (PCD) in both lower extremities in association with S. aureus sepsis, resulting in gangrene of the right foot. Non-pitting edema and cyanosis of the digits of the right lower extremity were noted 48 hours after hypotension and severe shock due to S. aureus sepsis. Intravenous antibiotics, isotonic fluids, and heparin were administered. Twenty-four hours later, edema and ischemic changes of the first and fifth left toes were also noted. Doppler flow study showed flow signals in both right and left popliteal arteries. However, there were no Doppler signals in neither right nor left popliteal vein. Emergency fasciotomies were performed on both lower limbs. The progression of the gangrene was limited to the right foot. There was complete resolution of PCD in both lower extremities. To the best of our knowledge, the association of S. aureus sepsis with PCD and venous gangrene in an infant has not been reported previously. This case illustrates the need for early recognition of PCD and aggressive intervention.

Previous studies during one-lung anaesthesia have demonstrated low arterial oxygen tension',' and the pulmonary venous admixture (shunt) was estimated from assumed values for the arterial-venous oxygen content difference,334 which however, were larger than those actually found under halothane anae~thesia.~ This resulted in an underestimate of the shunt. The present study was undertaken to measure the shunt under clinical conditions and to determine what effect varying the inhaled oxygen tension and respiration rate had on the shunt, arterial oxygen tcnsion and content. Methods and experimental designAll the studies were performed on consenting patients, undergoing elective intrathoracic surgery in the lateral position, for either localized peripheral lung tumours or extra-pulmonary conditions. Patients with significant cardiac disease, atelectasis or with FVC and/or FEV, less than 75% of predicted value were excluded. Anaesthesia was induced after pre-oxygenation, with thiopentone 5 mg/kg, or diazepam 0.4 mglkg. Suxamethonium 1.5 mg/kg was used to facilitate endobronchial intubation with a Robertshaw or Carlens double-lumen tube. The correct position of the tube was then confirmed by auscultation, and again after positioning of the patient for operation. Ventilation was maintained with the gas mixture appropriate to the study group, with a low concentration of halothane or methoxyflurane added. Ventilation was maintained with a Bennett or Engstrom ventilator at constant rate and constant tidal volume of 600-850 ml throughout the period of study, except during re-inflation of the lung, when manual inflations were used. Muscle relaxation was maintained with alcuronium or tubocurarine which was reversed at the end of the operation.Arterial blood samples were obtained through percutaneous cannulation of the radial or brachial artery by means of a 7 cm, 18 SWG teflon cannula. Venous samples were obtained from the right atrium by means of a soft polyvinyl chloride catheter.

The venous admixture was measured before, during, and after deflation of one lung during anaesthesia for thoracotomy in 10 subjects ventilated with 50% oxygen. The mean oxygen saturation fell from 99% before deflation of the lung to 89% after 30 minutes’ atelectasis. The pH and carbon dioxide tension did not change significantly. The shunt was 38% of cardiac output five minutes after and 41% 30 minutes after deflation. The reciprocal of the arterial venous oxygen content difference correlated positively with the shunt, suggesting that increased venous admixture is accompanied by increased cardiac output.