The use of 2-chloroprocaine for spinal anaesthesia.

Spinal anaesthesia is a safe and reliable anaesthetic modality for surgical procedures on the lower part of the body. However, because of the description of transient neurologic symptoms (TNS), most practitioners have abandoned intrathecal lidocaine. Chloroprocaine (2-chloroprocaine, CP) has been one candidate to replace lidocaine for short procedures, despite the fact that neurologic sequelae have been described following the intrathecal injection of large doses of preservative-containing CP intended for epidural use. The National Library of Medicine's Medline and the EMBASE databases were searched for the time period 1966 to April 2012. Fourteen studies of the use of intrathecal CP were analysed, including seven volunteer and seven clinical studies. Preservative-free CP appears to be a reliable local anaesthetic for short procedures. The duration of the surgical block can be adjusted by varying the dose between 30 and 60 mg. Two double-blind randomised controlled studies demonstrate decreased time to ambulation and discharge when CP is used for spinal anaesthesia when compared with other local anaesthetics. The addition of fentanyl appears to prolong the surgical block without significantly prolonging the time to discharge. There have been five possible cases of TNS following CP spinal anaesthesia in over 4000 patients, and a regressive incomplete cauda equina syndrome has been described. The short duration of spinal CP makes it a strong contender for outpatient anaesthesia. It appears to have a lower risk of TNS than lidocaine.

Refractory cardiac arrest in a rural area: mechanical chest compression during helicopter transport.

BACKGROUND: Out-of-hospital refractory cardiac arrest patients can be transported to a hospital for extracorporeal life support (ECLS), which can be either therapeutic or performed for organ donation. Early initiation is of vital importance and the main limitation when considering ECLS. This explains that all reported series of cardiac arrest patients referred for ECLS were urban ones. We report a series of rural out-of-hospital non-heart-beating patients transported by helicopter. METHODS: This observational study was performed in two rural districts in France. Data on patients with pre-hospital criteria for ECLS who were transported to the hospital by helicopter, maintained by mechanical chest compression, were recorded over a 2-year period. RESULTS: During the study period, 27 patients were referred for ECLS, of which 14 for therapeutic ECLS and 13 for organ preservation. The median transport distance was 37 km (25th and 75th percentiles: 31-58; range 25 to 94 km). Among the therapeutic ECLS patients, one survived to discharge from the hospital. Liver and kidneys were retrieved in another patient after brain death was ascertained. In the 13 patients referred for organ donation, four were excluded for medical reasons; 18 kidneys were retrieved in nine patients, of which six kidneys were successfully transplanted. CONCLUSION: In this preliminary study, we report the feasibility and the interest of helicopter transport of refractory cardiac arrest patients maintained by mechanical chest compression. Patients with refractory cardiac arrest occurring in rural areas, even at distance from a referral centre, can be candidates for ECLS.

Pre-hospital transcranial Doppler in severe traumatic brain injury: a pilot study.

BACKGROUND: Investigation of the feasibility and usefulness of pre-hospital transcranial Doppler (TCD) to guide early goal-directed therapy following severe traumatic brain injury (TBI). METHODS: Prospective, observational study of 18 severe TBI patients during pre-hospital medical care. TCD was performed to estimate cerebral perfusion in the field and upon arrival at the Level 1 trauma centre. Specific therapy (mannitol, noradrenaline) aimed at improving cerebral perfusion was initiated if the initial TCD was abnormal (defined by a pulsatility index >1.4 and low diastolic velocity). RESULTS: Nine patients had a normal initial TCD and nine an abnormal one, without a significant difference between groups in terms of the Glasgow Coma Scale or the mean arterial pressure. Among patients with an abnormal TCD, four presented with an initial areactive bilateral mydriasis. Therapy normalized TCD in five patients, with reversal of the initial mydriasis in two cases. Among these five patients for whom TCD was corrected, only two died within the first 48 h. All four patients for whom the TCD could not be corrected during transport died within 48 h. Only patients with an initial abnormal TCD required emergent neurosurgery (3/9). Mortality at 48 h was significantly higher for patients with an initial abnormal TCD. CONCLUSIONS: Our preliminary study suggests that TCD could be used in pre-hospital care to detect patients whose cerebral perfusion may be impaired.

Peripheral nerve injection injury with antiemetic agents.

Antiemetics are widely used drugs, frequently administered to alleviate postoperative and postchemotherapeutic nausea and vomiting. While antiemetics do not induce peripheral neurotoxicity when administered systemically, it is not known whether peripheral nerve injury can occur as a result of inadvertent intraneural injection during intramuscular administration. The purpose of this study was to characterize the neurotoxic effect of three commonly used antiemetic agents (promethazine, dimenhydrinate, and prochlorperazine) as compared to saline in the rat sciatic nerve model. Intrafascicular and extrafascicular injection as well as direct application of the antiemetic drugs were performed. Nerves were harvested at 2 weeks postoperatively for histology and morphometry, with an additional sacrifice point at 8 weeks for the intrafascicular injection group. Injection injuries caused by antiemetic drugs differed depending on the agent injected and the location of injection. Extrafascicular injection and direct application caused no damage. Intrafascicular injection caused diffuse axonal injury in the promethazine and dimenhydrinate groups, while prochlorperazine caused only focal injury. Regeneration was prominent at 8 weeks in all intrafascicular injection groups in this rat model. Prochlorperazine thus appears to be less neurotoxic when injected intraneurally and should preferentially be used for intramuscular injections.

Indefinite survival of peripheral nerve allografts after temporary Cyclosporine A immunosuppression.

It is hypothesized that unlike solid organ transplants immunosuppression of peripheral nerve allografts is needed only for the finite time period required for regeneration of proximal host nerve axons through the allograft and subsequent re-establishment of host end-organ connections. The aim of this study was to explore the consequences of temporary and continuous systemic Cyclosporine A (CsA) immunosuppression upon peripheral nerve allograft survival. Buffalo rats received Lewis nerve allografts under CsA immunosuppression (5 mg/kg/day) either continuously for 20 weeks, or for only 10 weeks followed by abrupt withdrawal. At 20 weeks, the nerve segments from both groups were regrafted into naïve Buffalo or Lewis recipients without further immunosuppression. These grafts were compared with isografts, unimmunosuppressed allografts and allografts immunosuppressed for 10 weeks in situ. By eight weeks following regrafting, the secondary Lewis recipients had rejected the temporarily immunosuppressed allografts and accepted the continuously immunosuppressed allograft, while the secondary Buffalo recipients accepted both the temporarily and continuously immunosuppressed allografts as assessed by histology and morphometry. Functional recovery was earlier in secondary recipient strain animals that received temporarily immunosuppressed allografts in comparison to those that received continuously immunosuppressed allografts. Analysis of secondary recipients of temporarily immunosuppressed allografts demonstrated greater in vitro MLR and LDA reactivity than did those receiving continuously immunosuppressed allografts. These findings support the hypothesis that donor alloantigens are lost or replaced by the recipient after immunosuppression withdrawal. Moreover, the change to recipient antigenicity in the nerve allograft is retarded and incomplete under continuous CsA immunosuppression, resulting in acceptance by both secondary donor and recipient strains upon regraftment.

The distally based medial gastrocnemius flap: case report and anatomic study.

We describe a distally based flap of the medial head of the gastrocnemius, vascularized through a distal pedicle given off by the posterior tibial artery. A literature review showed that this flap and the distal pedicle had not been described previously as such, although several techniques have been used to cover a substance loss of the distal third of the leg using the medial gastrocnemius. The distal artery has a variable caliber, and it is not always possible to raise the flap. One patient has been operated on by this technique, and an anatomic study was performed showing that 9 of 30 legs had a distal pedicle larger than 1 mm, 14 had a pedicle smaller than 1 mm, and 7 had a microscopic pedicle too small to raise a flap.

Nerve injection injury with botulinum toxin.

The therapeutic use of botulinum toxin (Botox) is increasing in popularity. Previous studies have shown that various drugs, especially when injected intrafascicularly, can cause major nerve damage. This study evaluates the potential for neurotoxicity of botulinum toxin in a rat sciatic nerve model. Lewis rats were randomly assigned to one of six groups (n = 10/group). Group 1, 2, and 3 rats received, respectively, an intrafascicular, extrafascicular, and extraneural injection of 50 microl of botulinum toxin (50 UI/ml). Group 4, 5, and 6 rats received 50 microl of 10% phenol as a positive control. Five animals received saline as a negative control. Animals were sacrificed at 2 and 7 weeks. Nerves were harvested and processed for histology and morphometry. Nerves in all botulinum toxin groups retained a normal architecture without cellular infiltration or demyelination. The number and diameter of fibers, the thickness of myelin, and the percentage of neural tissue were comparable with normal controls. Nerves injected intraneurally with phenol presented with severe damage, demyelination, and inflammation at 2 weeks and showed signs of early regeneration at 7 weeks. This study demonstrates that in a rat model, even direct intraneural injection of botulinum toxin caused no damage. This information should encourage the reconstructive surgeon to consider broader applications of this drug.

Update on prehospital emergency care of severe trauma patients.

The prognosis of severe trauma patients is determined by the ability of a healthcare system to provide high intensity therapeutic treatment on the field and to transport patients as quickly as possible to the structure best suited to their condition. Direct admission to a specialized center ("trauma center") reduces the mortality of the most severe trauma at 30 days and one year. Triage in a non-specialized hospital is a major risk of loss of chance and should be avoided whenever possible. Medical dispatching plays a major role in determining patient care. The establishment of a hospital care network is an important issue that is not formalized enough in France. The initial triage of severe trauma patients must be improved to avoid taking patients to hospitals that are not equipped to take care of them. For this purpose, the MGAP score can predict severity and help decide where to transport the patient. However, it does not help predict the need for urgent resuscitation procedures. Hemodynamic management is central to the care of hemorrhagic shock and severe head trauma. Transport helicopter with a physician on board has an important role to allow direct admission to a specialized center in geographical areas that are difficult to access.

The initial management of trauma patients is an especially relevant setting to evaluate professional practice patterns.

The initial management of trauma patients in a dedicated location is a crucial step in the treatment of these patients. The characteristics of this phase are such that they meet all the criteria for a professional practice patterns evaluation (PPPE or PPE): formalized protocols, clear-cut timeframes, specific roles of different stakeholders, and multidisciplinary medical and paramedical team. In addition, the expected result of the PPE approach, improved care, will have a direct impact on patient outcomes. This PPE modeled on an audit aims at evaluating the care process based on representative criteria. These criteria should include: the planned structure and organization; the protocols; the strategy and time frames for procedure implementation; the relationships between stakeholders; the results. For each criterion, differences between the expected characteristics and the observed reality are analyzed. The prospective (independent observer or video) and/or retrospective (records, register) collection of data during 20 consecutive encounters should be sufficient to identify dysfunctions and provide guidance on the changes that need to be implemented. The proposed data collection form includes 15 items representative of the five defined criteria. These items often describe departmental choice. The pursuit of quality is defined first in terms of medical and paramedical results, but also in administrative and financial terms. Following the analysis produced by a representative group of actors, a multidisciplinary discussion of the results should be followed by proposals for simple changes approved by everyone. After a few months of implementation, the impact of the proposed improvement measures will be assessed by a new survey. This approach, in addition to improving the quality of care, allows better team stress management and greater work enjoyment.

Experimental prevention of free flap thrombosis. I: A model of free flap failure.

A model to evaluate the efficacy of therapies aimed at reducing the failure rate of microvascular free flaps was developed in the rat, inspired by earlier work on the rabbit ear by Ozbek et al. (Ann Plast Surg 32:474-477, 1994). It consisted in raising an epigastric groin flap on the femoral pedicle, while cutting the femoral artery, twisting it around the femoral vein, and resuturing it. Immediate patency was always seen, but 19 of 20 such anastomoses presented with thrombosis after 24 hours (15 venous and 4 mixed thromboses). Ten similar anastomoses performed without twisting did not result in thrombosis (P = 0.000000366). This model appears to be adequate for simulating free flap failure.

Experimental prevention of free flap thrombosis. II: Normovolemic hemodilution for thrombosis prevention.

A microvascular free flap failure model consisting of raising an epigastric groin flap on the femoral pedicle, while cutting the femoral artery, twisting it around the femoral vein and resuturing it, has been previously described. As it was being evaluated, normovolemic hemodilution as a means to prevent thrombosis was simultaneously assessed using an additional experimental group. Twenty percent of the blood mass of each rat was taken and replaced with a hydroxyethyl starch solution immediately before surgery. Only 14 out of 20 anastomoses presented with thrombosis (13 venous and one mixed), as opposed to 19 out of 20 animals operated on without hemodilution (P< 0.05). Normovolemic hemodilution appears to be an effective method of reducing microvascular free flap failure.

Cold preservation of nerve grafts decreases expression of ICAM-1 and class II MHC antigens.

Cold preservation has previously been shown to decrease the antigenicity of nerve allografts, while Schwann cells remain viable. The expression of intercellular adhesion molecule-1 (ICAM-1) and class II MHC antigens, both of which have been shown to play a major role in initiating graft rejection, was studied in fresh rat nerve, and after 2 and 7 weeks of cold preservation. Ten sciatic nerves harvested from Lewis rats were cut into three segments. One segment was processed immediately, while the other ones were preserved at 5 degrees C for 2 and 7 weeks, respectively, before processing. Immunostains using specific monoclonal antibodies and alkaline phosphatase development were performed on each sample. The relative level of expression of these antigens was compared using computer-assisted densitometry. Expression of ICAM-1 was significantly decreased at 7 weeks, as compared to fresh and 2-week groups, with no statistically significant difference between fresh and 2-week nerves. Expression of class II MHC was significantly decreased at 2 and 7 weeks, compared to fresh nerves, with no statistically significant difference between the preserved groups. The decrease in antigenicity of cold-preserved nerve allografts appears to be linked to a down-regulation of ICAM-1 and MHC class II expression.

Development of the blood-nerve barrier in neonatal rats.

The blood-nerve barrier (BNB) is constituted by the perineurium and the endothelium of endoneurial microvessels. We investigated the age at which the vascular component of BNB function is established in the rat and the ultrastructural modifications accompanying changes in permeability. BNB permeability was assessed with injections of Evans blue albumin (EBA) and horseradish peroxidase (HRP) in rats of different ages. Sciatic nerve sections were studied using fluorescence and electron microscopy. Nerves from animals injected with EBA indicated that the BNB is not functional before 13 days of life but that its function is established by 16 days. These results were confirmed by electron microscope examination of nerve sections from animals injected with HRP, which showed clefts between the endothelial cells of endoneurial vessels in young rats. In rats over 18 days, these clefts were occluded by tight junctions, which prevented HRP from leaving the vessel lumen and conferred BNB function. Systematic morphometric analysis of nerves from different age groups allowed the establishment of baseline normal histologic neural development with age.

Small bowel fistulae in Degos' disease: a case report and literature review.

Degos' disease (malignant atrophic papulosis) is a rare, progressive, small- and medium-size arterial occluding disease, leading to tissue infarction and initially involving the skin. We report a case with bowel involvement followed by enterocutaneous fistulae. Diagnostic laparoscopy with jejunal biopsy was followed by jejunal perforations, peritonitis, and fistulae leading to death after a 4-month course in the intensive care unit. The usual treatment of enterocutaneous fistula by somatostatin and parenteral nutrition was ineffective in this case. The course of the disease in our patient was not usual, as can be seen in a literature review underlining the specific features of Degos' disease. Laparoscopy and bowel biopsy should be avoided in this context. Degos' disease should be considered in the differential diagnosis of a primary ulceration of the small intestine.

Regeneration through long nerve grafts in the swine model.

We investigated regeneration across a long nerve defect in the swine model to study extensive neural loss and long nerve gap. Most experiments have been conducted in the rodent model that, while an appropriate immunological model, only allows short nerve gaps to be studied. Twelve outbred swine received either an 8-cm ulnar nerve autograft or an allograft without immunosuppression. At 6 and 10 months, histomorphometry of the autografts demonstrated excellent nerve regeneration, while very poor regeneration was noted across the allografts. This confirmed that 8 cm are an adequate challenge independent of the spontaneous regeneration potential of axons seen in rodents. The swine ulnar nerve graft model causes minimal morbidity and will now be used with immunological manipulation of inbred animals.