A prospective, randomized clinical trial was performed in order to assess the efficacy and side-effects of commonly used topical anaesthesia methods in adults receiving peripheral venous cannulation. The study was double-blinded to the degree that the methodologies allowed. One hundred and fifty healthy adults undergoing elective surgery were allocated at random to five groups: EMLA cream, ethyl chloride spray, intracutaneous infiltration with 2% lidocaine, placebo cream and no treatment. Venipuncture was performed with a 18G cannula on the dorsal side of the hand. Puncture pain and pain caused by the topical treatment itself were measured using a visual analogue scale (VAS, range: 0-100 mm). Haemodynamic response, difficulties in performing the puncture and side-effects were recorded. All analgesic techniques were well tolerated. Haemodynamic response and degree of puncture difficulty showed no differences among the groups. Puncture pain (median mrnVAS) following infiltration (1.0) and EMLA (10.0) was significantly lower than no treatment (30.0) or placebo (30.0). The benefit of local infiltration was altered by injection pain (11.5). Spray did not significantly lower puncture pain (26.5) and, in addition, was associated with discomfort (10.5). In adults, EMLA cream significantly reduces puncture pain and represents an acceptable alternate method for topical anaesthesia in venous cannulation. Local lidocaine infiltration is impaired by applicational pain, whereas spraying the puncture site with ethyl chloride has no analgesic benefit.

A 78-year-old man was transferred from an outside hospital where he presented with declining mental status and a history of falls. A computed tomography (CT) scan of the brain revealed a chronic subdural hematoma with superimposed acute hemorrhage. The subdural hematoma was attributed to a fall at home approximately 5 weeks prior to admission. He was taken to the operating room for urgent craniotomy and hemorrhage evacuation and postoperatively comanaged by neurosurgery, hospitalists, and medicine residents. He tolerated the procedure and was noted to have marked improvement in mental status after the procedure. He was monitored overnight in our intensive care unit without intracranial pressure monitoring.Early on postoperative day 1, he was awake, alert, following commands, and felt to be stable enough to be transferred to our transitional intensive care unit. However, later in the day he became progressively more confused. A follow-up CT scan of the brain was ordered (Fig. 1) by the medicine team which revealed a large collection of air (wide arrow) and marked midline shift (thin arrow) consistent with tension pneumocephaly and subfalcine herniation ( Fig. 2; arrow). Examination revealed that he was grossly obtunded with marked anisocoria, decerebrate posturing, and rigid tone. Neurosurgery was immediately contacted and recommended accessing 2 indwelling catheters left in the cerebrum as part of the normal postoperative course. Approximately 100 mL of serosanguinous fluid and air was aspirated with immediate improvement in his mental status and exam findings. Over the next few days, he remained clinically stable, and repeat CT scan showed slow resolution of the pneumocephalus and a decrease of his mass effect and midline shift. He was ultimately transferred to our skilled nursing facility for physical therapy and has done relatively well.Pneumocephalus is a relatively common finding in many neurosurgical, intracranial procedures. However, tension pneumocephalus is a rare, life-threatening form of pneumocephalus in which intracranial air causes mass effect and midline shift. In a review of 295 cases of pneumocephalus, 75% were caused by surgery, mostly intracranial and transsphenoidal, and head trauma. About 9% of cases resulted from infection with gas-forming bacteria and rare causes include invasion of a nasopharyngeal carcinoma, frequent Valsalva maneuver, and air travel.

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