An 18 year-old female patient was scheduled for a craniotomy and excision of a mid-brain ependymoma in a seated position. Her clinical, biochemical and coagulation parameters were normal. In the operating theatre, standard monitors (electrocardiograph [ECG], non invasive blood pressure, pulse oximeter) were attached. General anesthesia was induced with fentanyl and thiopentone and intubation was facilitated with vecuronium. Anesthesia was maintained with oxygen, air, isoflurane, fentanyl and atracurium with controlled ventilation using a tidal volume of 500 ml and respiratory rate (RR) of 12 breaths/min to achieve normocarbia. Intra-operative monitoring (using a Datex Ohmeda S5) included heart rate, ECG, oxygen saturation by pulse oximetry, RR, end-tidal carbon dioxide (EtCO2), central venous pressure (CVP) (via the basilic vein), invasive blood pressure, airway pressure, volume of intravenous fluids infused, urine output, nasopharyngeal temperature, arterial blood gas (ABG), blood glucose and blood loss. Transesophageal echocardiography was not monitored as this was not available in our institute. There were no hemodynamic changes during moving the patient to a seated position. Baseline ABG analysis and CVP were normal.\nAt the time of opening of the dura, there was a sudden decrease in EtCO2 from 36 to 20 mmHg and then, further, to 15 mmHg. Concurrently there was a small tear in the occipital sinus. A VAE was therefore suspected. The EtCO2 changes observed during the VAE, with corresponding arterial blood gas analyses, are depicted in . There were no associated changes in hemodynamics or oxygenation. The EtCO2 returned to normal within a few minutes, following measures such as administration of 100% oxygen and prevention of further air entrainment through packing of the surgical site with saline-soaked gauze. The tear in the occipital sinus was identified and clipped.\nExcision of the tumor was uneventful, and intra-operative blood loss during the excision was around 500 ml. CVP was maintained at around 11-14 cmH2O. The patient remained hemodynamically stable. During the final stages of dura closure, application of the Valsalva maneuver was requested by the surgeon to check for cerebrospinal fluid leaks and assess the adequacy of hemostasis. Immediately after releasing the sustained positive pressure during the Valsalva maneuver, the EtCO2 again suddenly decreased from 30 to 9 mmHg, followed by a reduction in blood pressure to 62/30 mmHg and ST-T depression by 1 mmHg. Precordial auscultation at the apex of the heart revealed a mill-wheel murmur. The PaCO2 to EtCO2 gradient was 39 mmHg (). A massive VAE was contemplated and the surgeon was cautioned.\nImmediately, 100% oxygen was administered and the incision site was packed with saline-soaked gauze pieces. The patient was then repositioned in a left lateral recumbent position. About 50-60 ml of air was aspirated from the central venous catheter. She was resuscitated with 1 L of intravenous voluven® (6% hydroxyethyl starch 130/0.4 in 0.9% sodium chloride injection) and an injection of 6 mg mephenteramine. Blood pressure and EtCO2 returned to normal. The mill-wheel murmur disappeared. Soon afterwards, the rest of the surgical procedure was continued in the lateral position.\nAt the time of wound closure, bleeding was noted from the suture line and the wound was therefore reopened to check for the source of the bleeding. The bleeding from the wound was diffuse, with no identifiable bleeding site. An abnormality in coagulation was suspected. Since blood loss was high and hemostasis could not be obtained surgically, two units of packed red blood cells (PRBCs), four units of fresh frozen plasma (FFPs) and four units of platelet-rich plasma (PRPs) were administered without waiting for the coagulation profile report. Initially, the blood began to clot and the bleeding stopped. The patient was shifted to the neurosurgical intensive care unit for post-operative ventilation and observation. Later, there was continued oozing from the operative site and from the external ventricular drain (EVD). A post-operative computerized tomography scan of the brain showed a hematoma at the operative site, which was evacuated on the first post-operative (PO) day. Surgical findings showed further oozing from the operative site and surrounding cerebellar surfaces. These were corrected with blood and blood products. The patient's blood parameters and coagulation profile, with interventions made in the following PO days are shown in . There was continued oozing at the operative site and also from other intravenous and arterial cannulation sites. She deteriorated neurologically, showing clinical features of raised intracranial pressure and an EVD persistently draining blood. On the fourth PO day, inotropic support was initiated, as the patient developed persistent hypotension along with a decreasing Glasgow Coma Scale value and absent pupillary reaction. Finally, on the fifth PO day, she passed away despite resuscitative measures.
A 65-year-old lady with morbid obesity, hypertension, and rheumatoid arthritis was planned for total hip replacement under combined spinal and epidural anesthesia. Spinal anesthesia with 3 ml 0.5% of bupivacaine and 25 mcg of fentanyl was given at L3-4 interface with 26G Quinke's needle. Epidural space was identified at L2-3 level with a 18G Tuohy canula using loss of resistance technique with air (1 ml). The air filled syringe was disconnected soon after the loss of resistance. A 20G epidural catheter was introduced and fixed at 12 cm at the skin level. 5 min after the test dose, infusion was established at 2 ml/h with bupivacaine 0.125% and fentanyl (2 mcg/ml). Surgery lasted for around 8 h and epidural infusion was stopped at 6 h of surgery due to hypotension mostly due to bleeding (1100 ml). It was managed with fluids and blood transfusion through a peripheral cannula. In Intensive Care Unit for severe pain, she was prescribed an epidural bolus of 10 ml of 0.125% bupivacaine with 20 mcg of fentanyl along with IV tramadol 50 mg and promethazine 12.5 mg. With a lot of resistance, only 8 ml of the mixture could be injected over around 2 min. There was sudden bradycardia (73/min) and hypotension (systolic pressure 86 mmHg). She started jerking and gasping with suddenly diminished level of consciousness. Blood sugar was 242 mg% (13.44 mmol). Left pupil was noticed to be dilated and fixed. She was resuscitated with fluids and low dose noradrenaline and intubated.\nAn urgent computed tomography (CT) brain was done, which revealed air around the brain stem and no bleeding. Within 1 h she was awake but left pupil still remained dilated and fixed. She was extubated the next day. The mildly altered sensorium lasted for 2 days.