J. Mackenzie

Daycase anaesthesia and anxiety. A study of anxiety profiles amongst patients attending a day bed unit.

Two hundred adult patients aged 16–65 years scheduled to undergo operation under general anaesthesia in a Day Bed Unit were assessed for anxiety at the time of booking and on the day of operation. The nature of previous anaesthetic experience was the prime determinant of the anxiety scores obtained at booking. The score at booking was the prime determinant of the score on the day of operation, with previous experience and type of operation as secondary independent factors. Patients scheduled to undergo oral surgery were particularly anxious. Nineteen percent of patients would have liked to have received something to relieve their anxiety.

Acute pain management for opioid dependent patients

and above the functional residual capacity of that non-dependent lung. This already considerable volume of distension would have been greater if the degree of obstruction had been greater. The fact that there was an ongoing, albeit small, tidal gas movement in the non-ventilated lung following the venting of the 855 ml, confirms that the obstruction at the carina was very much a partial obstruction. In the worst possible case, that of a complete ballvalve effect, an overdistended lobe or lung would remain distended at a constant pressure approaching or equal to that of the peak inspiratory pressure [2]. Where the alveolar distension is of a lobe rather than a whole lung, the magnitude of the distension will be greater than if the whole lung were subjected to the same distending pressure. This is because during the expiratory phase the distended lobe can encroach on unaffected lung that is not under pressure [4]. In animal studies it is alveolar overdistension rather than over-pressure that is more likely to predispose to the development of pulmonary microvascular permeability [5, 6]. The tracings from Patient B also show that during two-lung ventilation the magnitude of the ‘iatrogenic’ intrinsic positive end-expiratory pressure (PEEP) at end-expiration in the partially obstructed right lung was approximately 1.6 kPa. Again, this maintained pressure would have been greater if the degree of bronchial obstruction were greater. With the right lung distended and under pressure it is not surprising that the plateau pressure during single-lung ventilation (at the end of the measurement sequence) was less than during two-lung ventilation (at the beginning of the sequence). My reason for wanting to see the tracing published, however embarrassing it might be for me, is to show just how potentially damaging a malpositioned bronchial cuff can be. If it were to occur in a lean patient with compliant lungs, ventilating pressures during two-lung ventilation (although higher than should otherwise be expected) would not necessarily alert the anaesthetist. Nor necessarily would hypoxaemia, which may well not develop when the patient is supine, or even after the patient is placed in the lateral position if the alveolar overdistension (of either an upper lobe or a whole lung) is present in the non-dependent lung. Even in Patient B, with the obstruction at the right main bronchial orifice being very much a partial obstruction, the right lung would most likely have collapsed down acceptably when the chest was opened, either thoracoscopically or at thoracotomy – and the period of alveolar distension could conceivably have gone undiagnosed.

Pre-operative femoral nerve block vs fascia iliaca block for femoral neck fracture - 4.

functional outcomes adversely in these patients [3]. We therefore believe that excluding such a large proportion of the population means that the conclusions from this study are less applicable in day-to-day practice. In their discussion, the authors state that the most common method of pain management includes the use of non-steroidal anti-inflammatory drugs (NSAIDs). We were rather concerned to read this, given their well-established side-effect profile and the fact that they are expressly not recommended in the NICE guidelines published over two years ago [4]. Extreme caution in their use was also stated in the AAGBI guidelines published in 2012 [5]. We wonder how many other institutions routinely use NSAIDs in this population. Finally, we note that of the 54 patients randomised to receive a femoral nerve block, three were then excluded from the study and further analysis due to technical failure in performing the block. We believe that the data should have been analysed on an intention to treat basis, hence including these three patients. It is not clear what mode of analgesia these patients eventually received. Given the relatively modest number of participants in the study and the fact that the difference between the two groups only just reached statistical significance for both the primary and secondary outcomes, we are unclear if any difference would have been statistically significant had the other three patients been included. In conclusion, whilst we appreciate the work that the authors have done, we do not feel that the conclusions drawn have external validity. We do appreciate the difficulty in conducting clinical research in this population and agree that the fascia iliaca block is so attractive because of its simplicity.

Patient-controlled epidural analgesia following post-traumatic pelvic construction

In his editorial (Anaesthesia 1993; 48: 101-2), Dr Bodenham elegantly argues the case for percutaneous tracheostomy. His comments concerning hospital approval are breaking new ground in anaesthesia. However, whether institutional approval has been received or not, we would urge some caution with this technique. Percutaneous tracheostomy using the Ciaglia technique was undertaken on a 51-year-old slim, female patient who required mechanical ventilation and haemodialysis following the development of acute renal failure consequent upon myonecrosis and haemoglobinuria. Prior to surgery, there was evidence of a degree of coagulopathy, with a platelet count of 70000 mm3, and a prothrombin time of 18 s (International Normalised Ratio, l .3) , and a Koalin-Cephalin time (KCCT) of 55 s (normal 40 s). She had not been dialysed for 26 h. Following discussion with our surgeons, and an infusion of 12 units of cryoprecipitate, percutaneous tracheostomy was performed in the operating theatre. Tracheal puncture with a needle, observed via a fibreoptic bronchoscope placed in the orotracheal tube, required a single stab, but the guidewire would not position, and two further punctures were required. Thereafter, following a 1.5 cm vertical incision, the subcricoid puncture was readily dilated and an 8.0 mm Portex cuffed tracheostomy tube inserted. The procedure took 15 min. She returned to the Intensive Therapy Unit. One hour later, peristomal bleeding became obvious and was significant at 2 h. She returned to the operating theatre. The tracheostomy tube was removed and a long cuffed oral tracheal tube inserted to allow continued ventilation and airway control. Exploration of the wound by the consultant surgeon disclosed two (arterial) bleeding points, in the midline, just superficial to the trachea. These were secured easily with surgical diathermy. At this point, reinsertion of the tracheostomy tube was required. The surgeon found difficulty establishing the site of the tracheal incision, which could only be seen by withdrawing the oral tube and sighting the gas leak. A urethral dilator was used to check the stoma position. Following its withdrawal, the tracheostomy tube was threaded onto the urethral bougie and the bougie reinserted into the subcricoid (second ring) slit. The tracheal tube was slid into the trachea over the bougie in the standard percutaneous tracheostomy fashion. Ventilation was not possible. The tracheal tube was removed and ventilation re-established via the oral tube, which had not been withdrawn from the laryngeal aperture. The tracheostomy tube was inserted (using the same urethral bougie) on the second attempt, and the operation completed rapidly. During the whole procedure, the patient did not suffer circulatory or respiratory compromise. While it might be argued that percutaneous tracheostomy in a patient with a bleeding diathesis is potentially hazardous (as we considered and found), the lesson to be learnt from this report was the difficulty of reinserting the percutaneous tracheostomy tube. At the time of reinsertion, patient positioning and lighting were excellent, and the patient was positioned identically to that for the first operation. There was no bleeding. Access was, however, not easy, not only because the skin incision was small, but also because the tracheal opening (a slit) could not be seen without assistance from the gas leak. Initial reinsertion of the tracheostomy resulted in extratracheal placement. If this tube had become dislodged in the Intensive Therapy Unit, a t any time before a track had formed (several days), reinsertion would have been impossible (and possibly hazardous, if the reinserted tube had been placed in tissues superficial to the trachea). In future, we shall instruct junior medical staff and our nurses to perform oral tracheal intubation should a percutaneous tracheostomy tube become displaced, and not to attempt reinsertion of the tube via the tracheostome. The latter route of reinsertion has proved straightforward in the past, when surgically placed tubes have had to be changed in the early postoperative period. Should percutaneously placed tubes require replacing, the old tube will require removing over a bougie.

Guidelines and use of dexamethasone for postoperative nausea and vomiting.

Catheter System (BD, Oxford, UK) was flushed with saline 0.9% on the postoperative surgical ward. This cannula was used at induction of anaesthesia with crystalloid running via one of its ports throughout, but we can only presume it failed to flush effectively. Unfortunately the cannula was not subsequently used as an 18-G single-port cannula was then sited and used for the rest of the case. The maximum dead space of the two ports and extension tubing of a 20-G Nexiva cannula is 0.5 ml. If unflushed after a rapid sequence induction this device can potentially lead to the administration of 25 mg suxamethonium, which is well beyond its ED50 and could easily produce generalised paralysis in a 70-kg adult [2]. Our case confirms the recommentation of Bowman et al. [3] that the only way to avoid this potentially life-threatening complication is to flush all cannula ports (regardless of their type or whether there is fluid running via the second lumen) with saline after administration of drugs, and that this should be a standard of care in adults as well as children.

Shivering and epidural blockade

variation in appearance was demonstrated (reference 4 above); each band consisted of strands of connective tissue (with the exception of two which presented with a complete membrane) which attached the dura to the dorsal aspect of the epidural space in a manner that fat alone possibly could not do. This attachment caused a dorsomedian fold of the dura mater which was accentuated by the introduction of the endoscope, needle and catheter (and, of course, by the very low or absent CSF pressure and absent circulation). These attachments of the dura to the dorsal aspect of the space were so strong in some cases, that at the end of the examination a forceful push of the endoscope against the dura mater was necessary in order to break them up. Such behaviour would not be expected if only fatty tissue were concerned. This appearance of the band has constantly recurred in epiduroscopic examinations in more than 30 cadavers as well as in 10 patients.’ The epidural space in vivo, also presented mainly as a potential space, as suggested by Dr Harrison. Support for the dorsomedian connective tissue band is given in a recent study of the epidural space with computerised tomography by Savolaine et aLz They verified the structure although they called it the ‘plica mediana dorsalis’; this is a term which, in my opinion, should be reserved to identify the fold in the dura mater that is caused by the connective tissue band. It, together with laterally extending connective tissue bands, divided the epidural space into potential compartments. A clinical study has just been completed in 50 patients subjected to transurethral resection of the prostate or resection of a bladder neoplasm with epidural analgesia, to compare the midline and paramedian approaches. The results of this study are now being analysed and will be presented in the near future.

Cardiovascular collapse following epidural anaesthesia for Caesarean section

rostrally beyond the analgesic lcvel’ and the block may not even have reached its full extent at 15 minutes. Subdural block may have occurred and the second dosc further compromised the patient. A block of the upper thoracic sympathetic outflow prevents the reflex vasoconstriction in vessels subserved from these segments which in less extensive epidural blocks serves to minimise changes in total peripheral res i~ tance ,~ and thereby maintain blood pressure. We arc told that the patient weighed 55 kg and so presumably was below average height. Regional anaesthesia may well be indicated in such a patient with cardiac failure but adequate monitoring (as employed in this case) and careful administration of anaesthetic agents to minimise predictable adverse effects are necessary whatever anaesthetic technique is adopted. The likelihood of inadvertent development of high epidural block may be minimised by employing a through-catheter incremental dosing technique which, although it entails establishing the block more slowly, must surely be safer in such at risk cases. 5