RESUMEN
BACKGROUND: It is common clinical practice to add diamorphine to heavy bupivacaine when performing spinal anaesthesia for either obstetric or general surgical procedures. If pre-filled syringes were available potential problems arising due to the wrong mixture being administered could be reduced, whilst also providing greater assurances of sterility and accuracy of dosage. It is therefore necessary to establish whether diamorphine 100 microg/mL is stable in solution with 0.5% hyperbaric bupivacaine, to allow production of pre-filled syringes for use in spinal anaesthesia. METHOD: Diamorphine hydrochloride was dissolved in water for injection, and added to hyperbaric bupivacaine then stored in 5-mL plastic syringes. Eleven syringes were stored at 40 degrees C/75% relative humidity, 25 degrees C/60% relative humidity and 7 degrees C for 90 days. Samples were taken at five time points for measurement of diamorphine and bupivacaine concentrations using high performance liquid chromatography. RESULTS: Diamorphine concentrations fell over the study period. No significant changes were observed the bupivacaine content of the samples. There was 10% degradation of diamorphine after 4 days at 40 degrees C, after 7 days at 25 degrees C, and after 26 days at 7 degrees C. CONCLUSION: Diamorphine is stable in hyperbaric bupivacaine at 7 degrees C for long enough to allow preparation of pre-filled syringes in advance (by hospital pharmacy aseptic units) for use in spinal anaesthesia.
Asunto(s)
Analgésicos Opioides , Anestésicos Combinados , Anestésicos Locales , Bupivacaína , Heroína , Jeringas , Anestesia Raquidea , Cromatografía Líquida de Alta Presión , Estabilidad de Medicamentos , Almacenaje de Medicamentos , TemperaturaRESUMEN
Intranasal administration of lipophilic opioids has been shown to be an effective method of administration which is devoid of major side-effects. Whether it is as effective as intravenous administration for patient-controlled analgesia (PCA) has been investigated for fentanyl and pethidine, but not for diamorphine. This study reports a randomised controlled trial designed to compare the effectiveness of diamorphine administered as PCA utilising either the intranasal or intravenous routes. We investigated 52 consecutive patients undergoing primary lower limb joint replacement surgery. Patients were randomly allocated to receive PCA diamorphine, administered either intravenously (0.5 mg bolus, 3 min lockout) or intranasally (1.0 mg bolus, 3 min lockout). Pain was assessed using a Visual Analogue Score (VAS) at rest and on movement on five occasions over the first 36 h postoperatively. The results demonstrated that patients in the intranasal PCA group had significantly higher VAS scores than the intravenous group, both at rest (intranasal median 35.5 vs. intravenous median 20; p = 0.030) and on movement (intranasal median 64 vs. intravenous median 50; p = 0.016). However, significantly fewer patients in the intranasal group compared with the intravenous group suffered episodes of vomiting (intranasal 0/24 vs. intravenous 6/24 patients; p = 0.022). We suggest that if a maximal reduction in pain score is considered the goal of PCA management, the intravenous route is preferable to the intranasal route.
Asunto(s)
Analgesia Controlada por el Paciente/métodos , Analgésicos Opioides/administración & dosificación , Heroína/administración & dosificación , Dolor Postoperatorio/tratamiento farmacológico , Administración Intranasal , Adulto , Anciano , Artroplastia de Reemplazo de Cadera , Artroplastia de Reemplazo de Rodilla , Femenino , Humanos , Inyecciones Intravenosas , Masculino , Persona de Mediana Edad , Dimensión del DolorRESUMEN
We studied the laryngoscopic view in 167 patients with their head and necks held in the neutral position with manual in-line stabilisation and cricoid pressure to simulate the patient with a suspected cervical spine injury. Each patient underwent laryngoscopy using both a McCoy and a Macintosh laryngoscope. The best view obtained by each larngoscope was graded according to standard guidelines. The results showed that the McCoy was never worse than the Macintosh. It improved the Macintosh grade by 1 grade in 41% and by 2 grades in 8% (p < 0.001). Difficult laryngoscopy, defined as the inability to see the glottis (grade 3 or 4), was found in 56 (33%) with the Macintosh laryngoscope and only eight (5%) (P < 0.001) with the McCoy laryngoscope. We suggest that patients with a suspected cervical spine injury and a full stomach should be intubated using a McCoy in preference to a Macintosh laryngoscope.