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2.
Br J Anaesth ; 113(4): 540-8, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25204695

RESUMEN

BACKGROUND: Accidental awareness during general anaesthesia (AAGA) with recall is a potentially distressing complication of general anaesthesia that can lead to psychological harm. The 5th National Audit Project (NAP5) was designed to investigate the reported incidence, predisposing factors, causality, and impact of accidental awareness. METHODS: A nationwide network of local co-ordinators across all the UK and Irish public hospitals reported all new patient reports of accidental awareness to a central database, using a system of monthly anonymized reporting over a calendar year. The database collected the details of the reported event, anaesthetic and surgical technique, and any sequelae. These reports were categorized into main types by a multidisciplinary panel, using a formalized process of analysis. RESULTS: The main categories of accidental awareness were: certain or probable; possible; during sedation; on or from the intensive care unit; could not be determined; unlikely; drug errors; and statement only. The degree of evidence to support the categorization was also defined for each report. Patient experience and sequelae were categorized using current tools or modifications of such. CONCLUSIONS: The NAP5 methodology may be used to assess new reports of AAGA in a standardized manner, especially for the development of an ongoing database of case reporting. This paper is a shortened version describing the protocols, methods, and data analysis from NAP5--the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home.


Asunto(s)
Anestesia General/efectos adversos , Despertar Intraoperatorio/epidemiología , Cognición/fisiología , Recolección de Datos/métodos , Interpretación Estadística de Datos , Bases de Datos Factuales , Medicina Basada en la Evidencia , Encuestas de Atención de la Salud , Paro Cardíaco/etiología , Humanos , Despertar Intraoperatorio/clasificación , Despertar Intraoperatorio/mortalidad , Complicaciones Intraoperatorias/etiología , Irlanda/epidemiología , Errores Médicos/estadística & datos numéricos , Bloqueo Neuromuscular/efectos adversos , Trastornos por Estrés Postraumático/etiología , Trastornos por Estrés Postraumático/psicología , Resultado del Tratamiento , Reino Unido/epidemiología
3.
Br J Anaesth ; 113(4): 560-74, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25204696

RESUMEN

The 5th National Audit Project (NAP5) of the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland into accidental awareness during general anaesthesia (AAGA) yielded data related to psychological aspects from the patient, and the anaesthetist, perspectives; patients' experiences ranged from isolated auditory or tactile sensations to complete awareness. A striking finding was that 75% of experiences were for <5 min, yet 51% of patients [95% confidence interval (CI) 43-60%] experienced distress and 41% (95% CI 33-50%) suffered longer term adverse effect. Distress and longer term harm occurred across the full range of experiences but were particularly likely when the patient experienced paralysis (with or without pain). The patient's interpretation of what is happening at the time of the awareness seemed central to later impact; explanation and reassurance during suspected AAGA or at the time of report seemed beneficial. Quality of care before the event was judged good in 26%, poor in 39%, and mixed in 31%. Three-quarters of cases of AAGA (75%) were judged preventable. In 12%, AAGA care was judged good and the episode not preventable. The contributory and human factors in the genesis of the majority of cases of AAGA included medication, patient, and education/training. The findings have implications for national guidance, institutional organization, and individual practice. The incidence of 'accidental awareness' during sedation (~1:15,000) was similar to that during general anaesthesia (~1:19,000). The project raises significant issues about information giving and consent for both sedation and anaesthesia. We propose a novel approach to describing sedation from the patient's perspective which could be used in communication and consent. Eight (6%) of the patients had resorted to legal action (12, 11%, to formal complaint) at the time of reporting. NAP5 methodology provides a standardized template that might usefully inform the investigation of claims or serious incidents related to AAGA.


Asunto(s)
Anestesia General/efectos adversos , Anestesia General/psicología , Anestesiología/legislación & jurisprudencia , Sedación Consciente/efectos adversos , Sedación Consciente/psicología , Despertar Intraoperatorio/psicología , Anestesiología/instrumentación , Comunicación , Encuestas de Atención de la Salud , Humanos , Consentimiento Informado , Despertar Intraoperatorio/epidemiología , Despertar Intraoperatorio/prevención & control , Irlanda/epidemiología , Errores Médicos/legislación & jurisprudencia , Errores Médicos/psicología , Memoria/efectos de los fármacos , Médicos , Calidad de la Atención de Salud , Trastornos por Estrés Postraumático/etiología , Trastornos por Estrés Postraumático/psicología , Encuestas y Cuestionarios , Reino Unido/epidemiología
4.
Br J Anaesth ; 113(4): 549-59, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25204697

RESUMEN

We present the main findings of the 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia (AAGA). Incidences were estimated using reports of accidental awareness as the numerator, and a parallel national anaesthetic activity survey to provide denominator data. The incidence of certain/probable and possible accidental awareness cases was ~1:19,600 anaesthetics (95% confidence interval 1:16,700-23,450). However, there was considerable variation across subtypes of techniques or subspecialities. The incidence with neuromuscular block (NMB) was ~1:8200 (1:7030-9700), and without, it was ~1:135,900 (1:78,600-299,000). The cases of AAGA reported to NAP5 were overwhelmingly cases of unintended awareness during NMB. The incidence of accidental awareness during Caesarean section was ~1:670 (1:380-1300). Two-thirds (82, 66%) of cases of accidental awareness experiences arose in the dynamic phases of anaesthesia, namely induction of and emergence from anaesthesia. During induction of anaesthesia, contributory factors included: use of thiopental, rapid sequence induction, obesity, difficult airway management, NMB, and interruptions of anaesthetic delivery during movement from anaesthetic room to theatre. During emergence from anaesthesia, residual paralysis was perceived by patients as accidental awareness, and commonly related to a failure to ensure full return of motor capacity. One-third (43, 33%) of accidental awareness events arose during the maintenance phase of anaesthesia, mostly due to problems at induction or towards the end of anaesthesia. Factors increasing the risk of accidental awareness included: female sex, age (younger adults, but not children), obesity, anaesthetist seniority (junior trainees), previous awareness, out-of-hours operating, emergencies, type of surgery (obstetric, cardiac, thoracic), and use of NMB. The following factors were not risk factors for accidental awareness: ASA physical status, race, and use or omission of nitrous oxide. We recommend that an anaesthetic checklist, to be an integral part of the World Health Organization Safer Surgery checklist, is introduced as an aid to preventing accidental awareness. This paper is a shortened version describing the main findings from NAP5--the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home.


Asunto(s)
Anestesia General/efectos adversos , Despertar Intraoperatorio/epidemiología , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Periodo de Recuperación de la Anestesia , Anestesia General/métodos , Anestesia Intravenosa/estadística & datos numéricos , Anestesia Obstétrica/efectos adversos , Peso Corporal , Niño , Preescolar , Sedación Consciente/efectos adversos , Sedación Consciente/psicología , Monitores de Conciencia , Cuidados Críticos/estadística & datos numéricos , Resistencia a Medicamentos , Femenino , Encuestas de Atención de la Salud , Humanos , Incidencia , Lactante , Despertar Intraoperatorio/terapia , Irlanda/epidemiología , Masculino , Errores Médicos/estadística & datos numéricos , Persona de Mediana Edad , Bloqueo Neuromuscular , Obesidad/complicaciones , Obesidad/epidemiología , Transferencia de Pacientes , Embarazo , Factores de Riesgo , Jeringas , Reino Unido/epidemiología , Adulto Joven
5.
Br J Anaesth ; 113(4): 575-84, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25236896

RESUMEN

BACKGROUND: Details of current UK anaesthetic practice are unknown and were needed for interpretation of reports of accidental awareness during general anaesthesia (GA) within the 5th National Audit Project. METHODS: We surveyed NHS anaesthetic activity to determine numbers of patients managed by anaesthetists and details of 'who, when, what, and where': activity included GA, local anaesthesia, sedation, or patients managed awake. Anaesthetists in NHS hospitals collected data on all patients for 2 days. Scaling enabled estimation of annual activity. RESULTS: Hospital response rate was 100% with 20,400 returns. The median return rate within departments was 98% (inter-quartile range 0.95-1). Annual numbers (% of total) of general anaesthetics, sedation, and awake cases were 2,766,600 (76.9%), 308,800 (8.6%), and 523,100 (14.5%), respectively. A consultant or career grade anaesthetist was present in more than 87% of cases. Emergency cases accounted for 23.1% of workload, 75% of which were undertaken out of hours. Specialties with the largest workload were orthopaedics/trauma (22.1%), general surgery (16.1%), and gynaecology (9.6%): 6.2% of cases were non-surgical. The survey data describe: who anaesthetized patients according to time of day, urgency, and ASA grade; when anaesthesia took place by day and by weekday; the distribution of patient types, techniques, and monitoring; where patients were anaesthetized. Nine patients out of 15 460 receiving GA died intraoperatively. CONCLUSIONS: Anaesthesia in the UK is currently predominantly a consultant-delivered service. The low mortality rate supports the safety of UK anaesthetic care. The survey data should be valuable for planning and monitoring anaesthesia services.


Asunto(s)
Anestesia/tendencias , Anestesiología/tendencias , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Anestesia/estadística & datos numéricos , Periodo de Recuperación de la Anestesia , Anestesia de Conducción , Anestésicos , Niño , Preescolar , Sedación Consciente/estadística & datos numéricos , Monitores de Conciencia , Consultores , Servicios Médicos de Urgencia/estadística & datos numéricos , Femenino , Cirugía General/estadística & datos numéricos , Cirugía General/tendencias , Encuestas de Atención de la Salud , Humanos , Lactante , Recién Nacido , Masculino , Auditoría Médica , Persona de Mediana Edad , Monitoreo Intraoperatorio , Monitoreo Fisiológico , Admisión del Paciente , Periodo Perioperatorio/mortalidad , Embarazo , Especialización , Medicina Estatal , Reino Unido , Adulto Joven
6.
Anaesthesia ; 69(10): 1078-88, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25204235

RESUMEN

Accidental awareness during general anaesthesia with recall is a potentially distressing complication of general anaesthesia that can lead to psychological harm. The 5th National Audit Project was designed to investigate the reported incidence, predisposing factors, causality and impact of accidental awareness. A nationwide network of local co-ordinators across all UK and Irish public hospitals reported all new patient reports of accidental awareness to a central database, using a system of monthly anonymised reporting over a calendar year. The database collected the details of the reported event, anaesthetic and surgical technique, and any sequelae. These reports were categorised into main types by a multidisciplinary panel, using a formalised process of analysis. The main categories of accidental awareness were: certain or probable; possible; during sedation; on or from the intensive care unit; could not be determined; unlikely; drug errors; and statement only. The degree of evidence to support the categorisation was also defined for each report. Patient experience and sequelae were categorised using current tools or modifications of such. The 5th National Audit Project methodology may be used to assess new reports of accidental awareness during general anaesthesia in a standardised manner, especially for the development of an ongoing database of case reporting. This paper is a shortened version describing the protocols, methods and data analysis from 5th National Audit Project - the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home#pt.


Asunto(s)
Anestesia General/efectos adversos , Protocolos Clínicos , Interpretación Estadística de Datos , Despertar Intraoperatorio/epidemiología , Auditoría Médica , Humanos
7.
Anaesthesia ; 69(10): 1089-101, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25204236

RESUMEN

We present the main findings of the 5th National Audit Project on accidental awareness during general anaesthesia. Incidences were estimated using reports of accidental awareness as the numerator, and a parallel national anaesthetic activity survey to provide denominator data. The incidence of certain/probable and possible accidental awareness cases was ~1:19 600 anaesthetics (95% CI 1:16 700-23 450). However, there was considerable variation across subtypes of techniques or subspecialties. The incidence with neuromuscular blockade was ~1:8200 (1:7030-9700), and without it was ~1:135 900 (1:78 600-299 000). The cases of accidental awareness during general anaesthesia reported to 5th National Audit Project were overwhelmingly cases of unintended awareness during neuromuscular blockade. The incidence of accidental awareness during caesarean section was ~1:670 (1:380-1300). Two thirds (82, 66%) of cases of accidental awareness experiences arose in the dynamic phases of anaesthesia, namely induction of and emergence from anaesthesia. During induction of anaesthesia, contributory factors included: use of thiopental; rapid sequence induction; obesity; difficult airway management; neuromuscular blockade; and interruptions of anaesthetic delivery during movement from anaesthetic room to theatre. During emergence from anaesthesia, residual paralysis was perceived by patients as accidental awareness, and commonly related to a failure to ensure full return of motor capacity. One third (43, 33%) of accidental awareness events arose during the maintenance phase of anaesthesia, most due to problems at induction or towards the end of anaesthesia. Factors increasing the risk of accidental awareness included: female sex; age (younger adults, but not children); obesity; anaesthetist seniority (junior trainees); previous awareness; out-of-hours operating; emergencies; type of surgery (obstetric, cardiac, thoracic); and use of neuromuscular blockade. The following factors were not risk factors for accidental awareness: ASA physical status; race; and use or omission of nitrous oxide. We recommend that an anaesthetic checklist, to be an integral part of the World Health Organization Safer Surgery checklist, is introduced as an aid to preventing accidental awareness. This paper is a shortened version describing the main findings from 5th National Audit Project - the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home#pt.


Asunto(s)
Anestesia General/efectos adversos , Despertar Intraoperatorio/etiología , Auditoría Médica , Humanos , Incidencia , Despertar Intraoperatorio/epidemiología , Factores de Riesgo
8.
Anaesthesia ; 69(10): 1102-16, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25204237

RESUMEN

The 5th National Audit Project of the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland into accidental awareness during general anaesthesia yielded data related to psychological aspects from the patient, and the anaesthetist, perspectives; patients' experiences ranged from isolated auditory or tactile sensations to complete awareness. A striking finding was that 75% of experiences were for < 5 min, yet 51% of patients (95% CI 43-60%) experienced distress and 41% (95% CI 33-50%) suffered longer-term adverse effect. Distress and longer-term harm occurred across the full range of experiences but were particularly likely when the patient experienced paralysis (with or without pain). The patient's interpretation of what is happening at the time of the awareness seemed central to later impact; explanation and reassurance during suspected accidental awareness during general anaesthesia or at the time of report seemed beneficial. Quality of care before the event was judged good in 26%, poor in 39% and mixed in 31%. Three quarters of cases of accidental awareness during general anaesthesia (75%) were judged preventable. In 12% of cases of accidental awareness during general anaesthesia, care was judged good and the episode not preventable. The contributory and human factors in the genesis of the majority of cases of accidental awareness during general anaesthesia included medication, patient and education/training. The findings have implications for national guidance, institutional organisation and individual practice. The incidence of 'accidental awareness' during sedation (~1:15 000) was similar to that during general anaesthesia (~1:19 000). The project raises significant issues about information giving and consent for both sedation and anaesthesia. We propose a novel approach to describing sedation from the patient's perspective which could be used in communication and consent. Eight (6%) of the patients had resorted to legal action (12, 11%, to formal complaint) at the time of reporting. The 5th National Audit Project methodology provides a standardised template that might usefully inform the investigation of claims or serious incidents related to accidental awareness during general anaesthesia.


Asunto(s)
Anestesia General/efectos adversos , Despertar Intraoperatorio/etiología , Auditoría Médica , Sedación Profunda , Humanos , Despertar Intraoperatorio/psicología , Memoria , Trastornos por Estrés Postraumático/etiología
11.
Transfus Med ; 16(2): 137-42, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16623920

RESUMEN

An important percentage of patients undergoing total hip replacement (THR) receive allogeneic blood transfusion (ABT) to avoid the risks of acute anaemia. However, concerns about the risks of ABT have led to the search for alternatives, such as stimulation of erythropoiesis. We prospectively investigated the effect of postoperative administration of 300 mg of intravenous iron sucrose on ABT requirements in THR patients (group 2; n = 24). A previous series of 22 THR patients served as the control group (group 1). All patients were operated on by the same surgeon, using the same implant, and a set of clinical data was gathered. No adverse reactions to iron administration were observed. The group-given iron showed a trend to a lower transfusion rate (46 vs. 73%; P = 0.067) and lower transfusion index (0.96 vs. 1.68 units/patient; P = 0.038). Moreover, amongst the non-transfused patients, admission haemoglobin levels were lower in those coming from the iron group than those from the control group (12.7 +/- 0.9 vs. 14.0 +/- 1.2 g dL(-1), respectively; P = 0.017). Postoperative parenteral iron administration could be a safe and effective way to reduce ABT requirements in the THR patients. A large, randomized controlled trial to confirm these results is warranted.


Asunto(s)
Anemia/prevención & control , Artroplastia de Reemplazo de Cadera , Transfusión Sanguínea , Compuestos Férricos/administración & dosificación , Anciano , Anciano de 80 o más Años , Anemia/etiología , Artroplastia de Reemplazo de Cadera/efectos adversos , Femenino , Sacarato de Óxido Férrico , Ácido Glucárico , Humanos , Infusiones Parenterales/métodos , Masculino , Proyectos Piloto , Estudios Retrospectivos
12.
Urol Int ; 75(1): 62-6, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16037710

RESUMEN

OBJECTIVES: Currently no consensus exists about the role of the foreskin or the effect circumcision has on penile sensitivity and overall sexual satisfaction. Our study assesses the effect of circumcision on sexually active men and the relative impact this may have on informed consent prior to surgery. MATERIALS AND METHODS: One hundred and fifty men between the ages of 18 and 60 years were identified as being circumcised for benign disease between 1999 and 2002. Patients with erectile dysfunction were excluded from the study. The data was assessed using the abridged, 5-item version of the International Index of Erectile Function (IIEF-5). Questions were also asked about libido, penile sensitivity, premature ejaculation, pain during intercourse and appearance before and after circumcision. IIEF-5 data was analysed using two-tailed paired t test to compare pre-operative and post-operative score changes across the study group. For the rest of the questions, data was analysed using 'Sign Test', calculating two-sided p values and 95% confidence intervals. RESULTS: Fifty-nine percent of patients (88/150) responded. The total mean IIEF-5 score was 22.41 +/- 0.94 and 21.13 +/- 3.17 before and after circumcision, respectively (p = 0.4). Seventy-four percent of patients had no change in their libido levels, 69% noticed less pain during intercourse (p < 0.05), and 44% of the patients (p = 0.04) and 38% of the partners (p = 0.02) thought the penis appearance improved after circumcision. Penile sensation improved after circumcision in 38% (p = 0.01) but got worse in 18%, with the remainder having no change. Overall satisfaction was 61%. CONCLUSIONS: Penile sensitivity had variable outcomes after circumcision. The poor outcome of circumcision considered by overall satisfaction rates suggests that when we circumcise men, these outcome data should be discussed during the informed consent process.


Asunto(s)
Circuncisión Masculina/psicología , Libido/fisiología , Satisfacción del Paciente , Erección Peniana/psicología , Pene/fisiología , Sensación/fisiología , Sexualidad/psicología , Adolescente , Adulto , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Encuestas y Cuestionarios , Resultado del Tratamiento
13.
Int Urol Nephrol ; 36(1): 41-4, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15338671

RESUMEN

OBJECTIVES: To review our experience with early radical cystectomy in patients with T1G3 Transitional Cell Carcinoma of bladder (TCC). PATIENTS AND METHODS: Thirty patients, who underwent early radical cystectomy over a 10-year period for clinical stage T1G3 TCC bladder, were studied. Of these 21 (70%) had radical cystectomy without treatment with intravesical chemo/immunotherapy. The number of tumours, presence or absence of Carcinoma In-Situ (CIS) and the pathological stage of the cystectomy specimen were recorded in each patient. Disease specific survival was determined in the subgroups using Kaplan-Meier estimates. RESULTS: Seventeen patients underwent radical surgery for a single tumour without concomitant CIS (Group A). The other 13 had multiple tumours with or without concomitant CIS or a single tumour with CIS (Group B). The disease was upstaged after cystectomy in 1 (6%) patient in Group A compared to 7 (55%) in Group B, (p = 0.009). Nine (53%) had pT0 disease in Group A compared to 0% in Group B, (p = 0.0017). The 5-year cancer specific survival rates were 92% in Group A and 82% in Group B. CONCLUSIONS: In patients with multiple T1G3 tumours with or without associated CIS, or in those with single T1G3 tumour with associated CIS the incidence of the disease being already muscle invasive at the time of clinical diagnosis is 55%. Early radical cystectomy should be advocated in this group. Conversely, for a single T1G3 tumour without associated CIS, conservative bladder preserving strategy with immuno-chemotherapy and close surveillance is justified.


Asunto(s)
Carcinoma de Células Transicionales/cirugía , Cistectomía , Neoplasias de la Vejiga Urinaria/cirugía , Anciano , Anciano de 80 o más Años , Carcinoma in Situ/patología , Carcinoma in Situ/cirugía , Carcinoma de Células Transicionales/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Vejiga Urinaria/patología
14.
Int J Clin Pract ; 57(9): 773-4, 2003 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-14686566

RESUMEN

The aim of this study was to elicit similarities and differences in transrectal ultrasound guided prostatic biopsy regimens in the UK and the Republic of Ireland. A telephone survey of 60 centres was conducted and information collected on the operator, the anaesthesia used, antibiotic prophylaxis and number of biopsies taken. Most prostatic biopsies were performed by urologists and most procedures involved six cores. There was a marked variation in the use of antibiotic prophylaxis, and anaesthesia was used sparingly. Our survey has shown a diversity in protocols used in transrectal ultrasound guided biopsies in the UK and Ireland. It seems sensible to standardise the technique for optimal patient satisfaction, as well as clinical efficiency. A national co-ordinated, prospective trial is needed.


Asunto(s)
Biopsia con Aguja/métodos , Pautas de la Práctica en Medicina , Próstata/patología , Neoplasias de la Próstata/patología , Anestesia Local , Biopsia con Aguja/efectos adversos , Encuestas de Atención de la Salud , Humanos , Irlanda , Masculino , Guías de Práctica Clínica como Asunto , Próstata/diagnóstico por imagen , Neoplasias de la Próstata/diagnóstico por imagen , Ultrasonografía Intervencional , Reino Unido
16.
Br J Plast Surg ; 55(5): 434-5, 2002 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12372375

RESUMEN

Snakebite envenomation is an uncommon condition in the UK, but requires vigilance with regard to both the systemic effects of the venom and the locoregional impact on the soft tissues. We describe a case requiring delayed fasciotomies for closed compartment syndrome of the leg and thigh, and discuss in detail the controversies surrounding decompression in such a case. Adder bites are uncommon in the UK, but can result in envenomation of varying severity. Apart from the numerous possible systemic effects that require attention, there are local effects that, very rarely, can be limb threatening. Of these, elevated limb compartment pressures are of paramount importance, and recognition of closed compartment ischaemia is vital if the limb is to be saved by surgical decompression. Guidelines on threshold compartment pressures and fasciotomies are indistinct regarding snakebite, with diagnostic emphasis still placed on clinical signs and symptoms. In the paediatric setting, measurement of compartment pressures is a valuable adjunct to clinical suspicion in the diagnosis of acute compartment syndrome secondary to snakebite.


Asunto(s)
Síndromes Compartimentales/etiología , Mordeduras de Serpientes/complicaciones , Viperidae , Animales , Niño , Síndromes Compartimentales/cirugía , Femenino , Humanos , Mordeduras de Serpientes/cirugía , Venenos de Víboras/envenenamiento
18.
Cytobios ; 104(407): 145-56, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11318510

RESUMEN

Butyl-methylmethacrylate resin mixtures were tested for brittleness-inducing factors in polymerised resin using a rapid quantitative scoring technique. The major source of brittleness was identified as the reducing agent dithiothreitol, which is commonly included in resin mixtures at 10 mM, to protect against tissue oxidation. Lowering the dithiothreitol content to 5 mM substantially reduced brittleness. Changing the 4:1 ratio of butyl- to methylmethacrylate to 9:1 or 3:2, and reducing the concentration of the catalyst, benzoin ethyl ether, to 0.25% also reduced dithiothreitol-induced brittleness. Polymerisation at temperatures close to 0 degrees C increased dithiothreitol-induced brittleness, but this was controlled in the 4:1 and 9:1 resin mixtures by lowering the catalyst concentration from 0.5 to 0.25%. Degassing the resin mixture with nitrogen gas prior to polymerisation did not reduce brittleness. Immunolabelled onion roots which were embedded using the 3:2 resin mixture ratio, 5 mM dithiothreitol and the 0.25% catalyst concentration, showed excellent preservation of cortical microtubule arrays.


Asunto(s)
Metilmetacrilatos/síntesis química , Resinas de Plantas/síntesis química , Resinas de Plantas/normas , Ditiotreitol/farmacología , Técnica del Anticuerpo Fluorescente/métodos , Metilmetacrilatos/química , Metilmetacrilatos/normas , Microscopía Fluorescente/métodos , Cebollas , Raíces de Plantas/ultraestructura , Docilidad/efectos de los fármacos , Resinas de Plantas/química , Adhesión del Tejido
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