Dose equivalence between metaraminol and norepinephrine in critical care.

AIMS: The aim of this study was to determine the conversion dose ratio between continuous infusion metaraminol and norepinephrine in critically ill patients with shock. METHODS: A retrospective cohort study was conducted in adult patients with shock admitted to an intensive care unit from 29 October 2018 to 30 October 2019 and who transitioned from metaraminol monotherapy to norepinephrine monotherapy. Mean arterial pressure (MAP) and infusion doses for both drugs were collected at hourly intervals; 2 hours before to 5 hours after switching from metaraminol monotherapy to norepinephrine monotherapy. The conversion dose ratio was defined as the ratio of metaraminol (µg.kg-1 .min-1) : norepinephrine (µg.kg-1 .min-1 ) required to achieve a similar MAP. RESULTS: A total of 43 out of 144 eligible patients were included. The median age was 68 years (IQR 56-76) and 22 (51%) were male. There was no significant difference between the baseline MAP during metaraminol monotherapy (median 71 mm Hg, IQR 66-76) and the post-transition MAP during norepinephrine monotherapy (median 70 mm Hg, IQR 66-73) (P = .09). The median conversion dose ratio between metaraminol and norepinephrine was 13 (IQR 7-24). In the sensitivity analyses, the median conversion dose ratio using the maximum and the mean norepinephrine infusion dose was 8 (IQR 5-16) and 12 (IQR 8-23), respectively. CONCLUSION: A conversion dose ratio of 10:1 (metaraminol µg.kg-1 .min-1 :norepinephrine µg.kg-1 .min-1 ) may be used in critically ill patients with shock to account for ease of calculations and variability of the conversion ratio in the primary and sensitivity analyses.

Predrawn prehospital medications are microbiologically safe for up to 48 hours.

BACKGROUND: Prehospital medical teams are commonly required to administer a range of medications for urgent stabilisation and treatment. The safe preparation of medications during resuscitation requires attention, time and resources, and can be a source of medication error. In our two road and HEMS (Helicopter Emergency Medical Service) prehospital services, medication errors are mitigated by predrawing commonly used medications to set concentrations daily (Hunter Retrieval Service, HRS) or second-daily (CareFlight Sydney, CFS). However, there are no published data confirming that such practice is microbiologically safe. METHODS: A convenience sample of 299 predrawn medication syringes with syringe dwell times up to 48 hours were collected at the end of their operational deployment. Predrawn medication syringes collected for culture were ketamine, midazolam, fentanyl, thiopentone, rocuronium, suxamethonium, metaraminol and normal saline. The samples were incubated and cultured at a tertiary hospital pathology laboratory using best-practice methodology for non-tissue samples. The samples were collected from June 2017 to February 2018. RESULTS: The mean dwell times ranged from 30.7 hours (fentanyl at HRS) to 48.5 hours (rocuronium at CFS). None of the 299 cultured samples yielded significant micro-organisms. One sample of suxamethonium with a syringe dwell time of 34 hours grew Bacillus cereus but was likely a contaminant introduced during sample collection. CONCLUSION: Predrawing of the eight studied medications for urgent prehospital procedures appears to be a microbiologically safe practice with syringe dwell times up to 48 hours.

The use of vasopressors during spinal anaesthesia for caesarean section.

PURPOSE OF REVIEW: Hypotension remains one of the most researched subjects in obstetric anaesthesia. The purpose of this study is to review the most recent published articles on the use of vasopressors during spinal anaesthesia for caesarean section. RECENT FINDINGS: Despite continued research indicating advantages of phenylephrine over ephedrine, practitioners in some countries continue to favour ephedrine. Recent research has continued to compare the two drugs with some work emerging on high-risk patients. Concern about reflexive bradycardia during phenylephrine use has led to consideration of alternatives. Norepinephrine which has mild ß-adrenergic activity has been shown to have equivalent pressor activity but with less depressant effect on heart rate and cardiac output versus phenylephrine. Research continues to focus on methods of vasopressor administration. Prophylactic infusions of phenylephrine have been shown to be effective and may require less physician intervention compared with intermittent boluses. Automated computer-controlled systems have been further investigated using multiple agents and continuous noninvasive blood pressure monitoring. SUMMARY: Evidence continues to support phenylephrine as the first-line vasopressor in obstetrics. However, recent research is emerging to suggest that low-dose norepinephrine may be a better alternative. Prophylactic infusions are effective and automated systems have potential for the future.

Comparison of metaraminol, phenylephrine and ephedrine in prophylaxis and treatment of hypotension in cesarean section under spinal anesthesia / Avaliação comparativa entre metaraminol, fenilefrina e efedrina na profilaxia e no tratamento da hipotensão em cesarianas sob raquianestesia / Evaluación comparativa entre el metaraminol, la fenilefrina y la efedrina en la profilaxis y en el tratamiento de la hipotensión en cesáreas bajo anestesia espinal

Maternal hypotension is a common complication after spinal anesthesia for cesarean section, with deleterious effects on the fetus and mother. Among the strategies aimed at minimizing the effects of hypotension, vasopressor administration is the most efficient. The aim of this study was to compare the efficacy of phenylephrine, metaraminol, and ephedrine in the prevention and treatment of hypotension after spinal anesthesia for cesarean section. Ninety pregnant women, not in labor, undergoing cesarean section were randomized into three groups to receive a bolus followed by continuous infusion of vasopressor as follows: phenylephrine group (50 μg + 50 μg/min); metaraminol group (0.25 mg + 0.25 mg/min); ephedrine group (4 mg + 4 mg/min). Infusion dose was doubled when systolic blood pressure decreased to 80% of baseline and a bolus was given when systolic blood pressure decreased below 80%. The infusion dose was divided in half when systolic blood pressure increased to 120% and was stopped when it became higher. The incidence of hypotension, nausea and vomiting, reactive hypertension, bradycardia, tachycardia, Apgar scores, and arterial cord blood gases were assessed at the 1st and 5th minutes. There was no difference in the incidence of hypotension, bradycardia, reactive hypertension, infusion discontinuation, atropine administration or Apgar scores. Rescue boluses were higher only in the ephedrine group compared to metaraminol group. The incidence of nausea and vomiting and fetal acidosis were greater in the ephedrine group. The three drugs were effective in preventing hypotension; however, fetal effects were more frequent in the ephedrine group, although transient.

Hipotensão materna é uma complicação comum após raquianestesia em cirurgia cesariana, trazendo efeitos deletérios para o feto e a mãe. Entre as estratégias com o objetivo de minimizar os efeitos da hipotensão, a administração de vasopressores é a mais eficiente. O objetivo deste estudo foi comparar a eficácia da fenilefrina, metaraminol e efedrina na prevenção e tratamento de hipotensão após raquianestesia em cirurgia cesariana. Noventa gestantes que não estavam em trabalho de parto submetidas à cesariana eletiva foram randomizadas em três grupos para receber um bolus, seguido de infusão contínua de vasopressor da seguinte forma: Grupo Fenilefrina (50 μg + 50 μg/min); Grupo Metaraminol (0,25 mg + 0,25 mg/min); Grupo Efedrina (4 mg + 4 mg/min). A dose da infusão foi dobrada quando a pressão arterial sistólica (PAS) decresceu até 80% dos valores basais e um bolus foi dado quando a PAS decresceu para valores abaixo de 80%. A dose da infusão foi dividida ao meio quando a PAS aumentou até 120% e foi interrompida quando mais elevada. Foram analisadas as incidências de hipotensão, náuseas e vômitos, hipertensão reativa, bradicardia, taquicardia e escores de Apgar no primeiro e quinto minutos e gases de sangue arterial do cordão umbilical. Não houve diferenças nas incidências de hipotensão, bradicardia, hipertensão reativa, interrupção da infusão, administração de atropina ou escores de Apgar. A administração de bolus de resgate foram superiores apenas no Grupo Efedrina em comparação com Metaraminol. A incidência de náuseas e vômitos e acidose fetal foram superiores no Grupo Efedrina. Os três fármacos foram eficazes na prevenção de hipotensão, mas repercussões fetais foram mais frequentes no Grupo Efedrina, embora transitórias.

La hipotensión materna es una complicación común posterior a la anestesia espinal en cirugía de cesárea, lo que trae efectos perjudiciales para el feto y la madre. Entre las estrategias cuyo objetivo es minimizar los efectos de la hipotensión, la administración de vasopresores es la más eficaz. El objetivo de este estudio fue comparar la eficacia de la fenilefrina, del metaraminol y de la efedrina en la prevención y el tratamiento de la hipotensión posterior a la aplicación de la anestesia espinal en cirugía de cesárea. Noventa gestantes que no estaban de parto y sometidas a la cesárea electiva, fueron aleatorizadas en 3 grupos para recibir un bolo, seguido de infusión continua de vasopresor de la siguiente forma: grupo fenilefrina (50 μg + 50 μg/min); grupo metaraminol (0,25 mg + 0,25 mg/min); grupo efedrina (4 mg + 4 mg/min). La dosis de la infusión se duplicó cuando la presión arterial sistólica cayó al 80% de los valores basales y un bolo se administró cuando la presión arterial sistólica cayó a valores por debajo del 80%. La dosis de la infusión se dividió en 2 cuando la presión arterial sistólica aumentó alcanzando los 120% y fue interrumpida cuando se elevó. Se analizaron las incidencias de hipotensión, náuseas y vómitos, hipertensión reactiva, bradicardia, taquicardia y puntuaciones de Apgar en el primer y en el quinto minutos, y gases de sangre arterial del cordón umbilical. No hubo diferencias en las incidencias de hipotensión, bradicardia, hipertensión reactiva, interrupción de la infusión, administración de atropina o puntuaciones de Apgar. La administración de bolos de rescate fue superior solo en el grupo efedrina en comparación con el metaraminol. La incidencia de náuseas y vómitos y la acidosis fetal fueron superiores en el grupo efedrina. Los 3 fármacos fueron eficaces en la prevención de la hipotensión y las repercusiones fetales fueron más frecuentes en el grupo efedrina, aunque hayan sido transitorias.

Serum oxytocin concentrations in elective caesarean delivery: a randomized comparison of three infusion regimens.

BACKGROUND: The aim of this study was to determine serum oxytocin concentrations following different regimens of prophylactic oxytocin administration in women undergoing elective caesarean delivery. METHODS: Thirty healthy pregnant patients were randomized, after clamping of the umbilical cord, to receive intravenous oxytocin in one of the following groups: G1 (n=9), 10 IU of oxytocin infused over 30 min (0.33 IU/min); G2 (n=11), 10 IU of oxytocin infused over 3 min and 45 s (2.67 IU/min); and G3 (n=10), 80 IU of oxytocin infused over 30 min (2.67 IU/min). Both patient and surgeon were blinded to allocation. Uterine tone was assessed by surgical palpation. Serum oxytocin concentration was determined by enzyme immunoassay before anaesthesia (T0) and at 5 (T5), 30 (T30) and 60 (T60) min after the start of oxytocin infusion. RESULTS: Serum oxytocin concentrations (mean±standard error, ng/mL) were not significantly different in the groups at T0 (0.06±0.02, 0.04±0.02 and 0.07±0.04, respectively, P=0.76), and T60 (0.65±0.26, 0.36±0.26 and 0.69±0.26, respectively, P=0.58). G3 showed higher concentrations than G1 at T5 (3.65±0.74 versus 0.71±0.27, P=0.01) and at T30 (6.19±1.19 versus 1.17±0.37, P<0.01), and were higher than G2 at T30 (6.19±1.19 versus 0.41±0.2, P<0.01). Haemodynamic data and uterine tone were considered satisfactory and similar in all groups. No additional uterotonic agents were needed. CONCLUSION: Serum oxytocin measurements made using enzyme immunoassay in healthy pregnant women undergoing elective caesarean delivery showed that administration of 80 IU oxytocin over 30 min resulted in higher serum oxytocin levels after 5 and 30 min than the two other regimens. The concentrations did not differ between groups at 60 min.

Vasopressores em bloqueios do neuroeixo para cesariana / Vasopressors in neuraxial anesthesia at cesarean sections

Justificativa e objetivos: Os fármacos vasopressores sempre apresentaram um lugar de destaque no controle da hipotensão arterial relacionada aos bloqueios do neuroeixo em anestesia obstétrica. Este artigo tem o objetivo de discutir os diversos fármacos utilizados na prática clínica e as inúmeras estratégias descritas na literatura para a prevenção e tratamento da hipotensão arterial pós-raquianestesia para cesariana. Conteúdo: Com a popularização da raquianestesia como técnica mais utilizada em anestesia para cesariana, os vasopressores tornaram-se pedra angular para a melhoria dos resultados maternos e fetais. Várias mudanças de paradigmas se apresentam nos dias atuais, destacando-se a segurança na utilização de fármacos alfa-agonistas, particularmente a fenilefrina. A efedrina já não tem sido mais considerada a primeira escolha em anestesia obstétrica, pois pode causar redução no pH fetal. Conclusões: A administração pro-filática e/ou terapêutica de agonistas alfa-adrenérgicos mostra-se segura e eficaz para o controle da hipotensão arterial pós-raquianestesia, otimizando os resultados maternos e fetais. Portanto, sugere-se revisão de conceitos.

Justification and objectives: vasopressor drugs have always been highlighted for the control of hypotension related to neuraxial blockade in obstetrical anesthesia. This article purpose is arguing the several drugs used in the clinical practice and the countless strategies described in the literature for the prevention and treatment of arterial hypotension after spinal anesthesia for caesarian section. Content: With the popularization of spinal anesthesia as the technique most used in anesthesia for caesarian section, vasopressors became the angular stone for the improvement of the maternal and fetal outcomes. Several changes of paradigms are introduced currently, highlighting the safe use of alpha-agonist drugs, particularly phenylephrine. Ephedrine has no longer been considered the unique first choice in obstetrical anesthesia, because it may cause reduction in fetal pH. Conclusions: The alpha adrenergic prophylactic and/or therapeutic administration proved to be a safe and effective option for the hypotension control after spinal anesthesia, optimizing the maternal and fetal outcomes. Therefore, that is the time for reviewing old concepts.

Myocardial infarction associated with the administration of intravenous ephedrine and metaraminol for spinal-induced hypotension.

A 31-year-old female with no risk factors for cardiac disease suffered a peri-operative myocardial infarction during an elective gynaecological procedure under spinal anaesthesia. The timing and nature of cardiac symptoms suggest that the myocardial infarction was caused by coronary artery vasospasm secondary to ephedrine and/or metaraminol, which were administered to treat spinal-induced hypotension. We review the recent literature and case reports on myocardial infarction attributed to sympathomimetic drugs, and recommend the use of sublingual or intravenous nitrates when signs or symptoms of coronary arterial vasospasm become evident during their use.

Which vasopressor for caesarean section?

One of the longest running debates in obstetric anaesthesia surrounds the prevention and treatment of maternal hypotension during caesarean section. Anaesthetic techniques have evolved and maternal mortality and morbidity is markedly reduced, but hypotension remains a problem, particularly following neuraxial blockade. Despite over 30 years of research no definitive consensus has been reached on the best treatment strategy and particular controversy surrounds the use of vasopressive agents. This article explores the evidence relating to the three most commonly used agents in the UK: ephedrine, phenylepherine and metaraminol.

Effect of dopamine and metaraminol on the renal function of patients with septic shock.

BACKGROUND: Vasoactive drugs are often necessary for reversing hypotension in patients with severe infection. The standard for evaluating effects of vasoactive drugs should not only be based on the increase of arterial blood pressure, but also on the blood flow perfusion of internal organs. The effects of dopamine and metaraminol on the renal function of the patients with septic shock were investigated retrospectively in this study. METHODS: Ninety-eight patients with septic shock were divided into three groups according to the highest infusing rate of metaraminol, with the lightest infusing rate of (0.1 - 0.5, 0.6 - 1.0, > 1.0) microgxkg(-1)xmin(-1) in group A, B and C respectively. Urine output, mean arterial blood pressure (MAP), heart rate (HR), urine output, blood urea nitrogen (BUN), creatinine (CRE), urine albumin (U-ALB), urine beta(2)-microglubulin (Ubeta(2)-MG) and Apache III scores were recorded. RESULTS: Before antishock therapy, hypotension, tachycardia and oliguria occurred to all the 98 patients with septic shock and CRE, BUN, U-ALB, Ubeta(2)-MG and Apache III scoring were abnormal in most cases. With the antishock therapy, MAP, HR, urine output, BUN and CRE in all patients returned gradually to normal (P < 0.05 or < 0.01 compared to those before antishock therapy). U-ALB, Ubeta(2)-MG output and Apache III scoring also reverted but remained abnormal (P < 0.01 compared to those before antishock therapy). No statistically significant differences in the changes of these indices with the time existed among the three groups (P > 0.05). CONCLUSION: Dopamine and metaraminol when applied to the patients with septic shock could effectively maintain the circulatory stability and promote restoration of renal function.

Vasoactive drugs in the intensive care unit.

PURPOSE OF THE REVIEW: Vasoactive drugs are the mainstay of hemodynamic management of vasodilatory shock when fluids fail to restore tissue perfusion. In this review, studies published during the past year that increase our understanding of the use of vasoactive drugs in the intensive care unit are discussed. RECENT FINDINGS: In septic shock, there is no benefit in increasing mean arterial pressure from 65 to 85 mmHg. Norepinephrine did not worsen renal function. Epinephrine induced visceral hypoperfusion and hyperlactatemia, and worsened organ function and survival compared with norepinephrine and vasopressin. There are a number of reports of the safety and efficacy of vasopressin but it is not currently recommended as first line therapy, and if used, should be given as a continuous low dose infusion. Terlipressin is showing promise but decreases cardiac output. Metaraminol is being investigated as an alternative to norepinephrine. Dopamine may improve splanchnic flow mainly by increasing cardiac output. Dobutamine improves oxygen delivery and may improve mesenteric blood flow. SUMMARY: Over the last 40 years, there have been few controlled clinical trials to guide clinicians on the use of vasoactive drugs of treating shock states. It is not known whether the currently favored combination of norepinephrine and dobutamine is superior to traditional therapy with dopamine. Epinephrine is not recommended as the first-line therapy. The role of vasopressin and terlipressin remains unknown. Three large ongoing clinical trials will be completed soon and the results should clarify the role of these various agents.

Metaraminol (Aramine) in the management of a significant amlodipine overdose.

OBJECTIVE: To report a patient with a significant amlodipine self-poisoning who failed to clinically respond to conventional treatment and was managed with metaraminol (Aramine). PATIENT: A 43-year old male presenting after ingestion of 560 mg amlodipine, who failed to respond clinically to treatment with fluid resuscitation, calcium salts, glucagon and norepinephrine/epinephrine inotropic support. MAIN RESULTS: Following a loading bolus of 2 mg and intravenous infusion (83 microg/min) of metaraminol (Aramine) there was improvement in his blood pressure, cardiac output and urine output. CONCLUSIONS: This is the first case report of the beneficial use of metaraminol (aramine) in the management of significant amlodipine poisoning unresponsive to conventional therapy.

Use of alpha-agonists for management of anaphylaxis occurring under anaesthesia: case studies and review.

Anaphylaxis is an uncommon but serious complication of anaesthesia. Most current guidelines for the management of anaphylaxis list only epinephrine as a vasopressor to use in the event of cardiovascular collapse. We present two cases of anaphylaxis under anaesthesia where return of spontaneous circulation was refractory to epinephrine, but occurred following the administration of the alpha-agonist metaraminol. Potential advantages and disadvantages of using epinephrine in this setting, the role of alpha-agonists and some potential mechanisms accounting for their role in successful management are reviewed.

Expansão volêmica em raquianestesia para cesariana: como realizá-la? / Fluid preload in obstetric patients: how to do it?

JUSTIFICATIVA E OBJETIVOS: Em pacientes não obstétricas, demonstrou-se que a expansão volêmica rápida realizada imediatamente após a injeção subaracnóidea do anestésico local era mais efetiva que a expansão volêmica lenta, realizada previamente à instalação do bloqueio para se reduzir a incidência e a gravidade da hipotensão arterial após raquianestesia. O objetivo do estudo foi comparar a incidência de hipotensão arterial e o consumo de vasopressores em gestantes submetidas à cesariana sob raquianestesia com diferentes regimes de expansão volêmica. MÉTODO: Foram avaliadas prospectivamente 60 gestantes de termo submetidas à cesariana sob raquianestesia. As pacientes receberam expansão volêmica com 10 ml.kg-1 de solução de Ringer com lactato como segue: Grupo 1 (n = 20), antes da raquianestesia através de cateter 18G; Grupo 2 (n = 20), após a raquianestesia e com cateter 18G e Grupo 3 (n = 20) após a raquianestesia com cateter 16G sob ação de pressurizador. A pressão arterial (PA) foi monitorizada a cada minuto e administrou-se 0,2 mg de metaraminol para qualquer diminuição de PA, a partir do valor de controle e 0,4 mg para diminuição > 20 por cento. A PA controle foi definida como a média de três valores sucessivos de pressão arterial sistólica obtidos antes da expansão volêmica e do bloqueio. Estudou-se a velocidade de infusão de fluidos, incidência de hipotensão arterial materna, náusea e vômito, consumo de metaraminol, índice de Apgar e pH da artéria umbilical. RESULTADOS: A velocidade de administração de fluidos foi maior no Grupo 3 do que nos Grupos 1 e 2 (201 ± 61 vs 56 ± 13 e 59 ± 21 ml.min-1, p < 0,05). Os grupos foram semelhantes em relação à incidência de hipotensão arterial, náusea, vômito, consumo de metaraminol, índice de Apgar e pH da artéria umbilical. CONCLUSÕES: A expansão volêmica, realizada antes ou após a instalação da raquianestesia, de maneira rápida ou lenta, não modifica o consumo de vasopressor, a ocorrência de hipotensão arterial mat...

BACKGROUND AND OBJECTIVES: In has been shown in non-obstetric patients, that a fast acute fluid preload immediately after spinal anesthesia was more effective than a slow preload before regional block to decrease the incidence and severity of arterial hypotension after spinal anesthesia. This study aimed at comparing the incidence of arterial hypotension and vasopressants consumption in parturients submitted to C-section under spinal anesthesia with different fluid preload regimens. METHODS: Sixty term pregnant women submitted to C-section under spinal anesthesia. Patients were randomly distributed in three groups receiving acute preload (10 ml.kg-1 lactated Ringer's) as follows: Group 1 (n = 20), before spinal anesthesia through 18G catheter; Group 2 (n = 20), after spinal anesthesia through 18G catheter and Group 3 (n = 20), after spinal anesthesia through 16G catheter with pressurizer. Blood pressure (BP) was monitored at 1-minute intervals until delivery and 0.2 mg bolus metaraminol was administered for any BP decrease from baseline values; 0.4 mg was administered for BP decrease > 20%. Control blood pressure was defined as the mean of three successive SBP values obtained before acute preload and spinal block. Variables studied were: preload rate, incidence of maternal arterial hypotension, nausea, vomiting, vasopressants consumption, Apgar scores and umbilical artery pH. RESULTS: Acute preload was faster in Group 3 as compared to Groups 1 and 2 (201 ± 61 vs 56 ± 13 and 59 ± 21 ml.min-1, p < 0.05). Groups were similar regarding the incidence of arterial hypotension, nausea and vomiting, metaraminol consumption, Apgar scores and umbilical artery pH. CONCLUSIONS: Acute preload before or after spinal anesthesia performance, in a slow or fast rate, does not change vasopressants consumption, the incidence of maternal arterial hypotension, nausea and vomiting, as well as fetal wellbeing.

JUSTIFICATIVA Y OBJETIVOS: En pacientes no obstétricas, se demostró que la expansión volémica rápida realizada inmediatamente después de la inyección subaracnoidea del anestésico local era más efectiva que la expansión volémica lenta, realizada previamente a la instalación del bloqueo para reducir la incidencia y la gravedad de la hipotensión arterial después de raquianestesia. El objetivo del estudio fue comparar la incidencia de hipotensión arterial y el consumo de vasopresores en embarazadas sometidas a cesárea bajo raquianestesia con diferentes regímenes de expansión volémica. MÉTODO: Fueron evaluadas prospectivamente 60 embarazadas de término sometidas a cesárea bajo raquianestesia. Las pacientes recibieron expansión volémica con 10 ml.kg-1 de solución de Ringer con lactato como sigue: Grupo 1 (n = 20), antes de la raquianestesia a través de catéter 18G; Grupo 2 (n = 20), después de raquianestesia y con catéter 18G y Grupo 3 (n = 20) después de raquianestesia con catéter 16G bajo acción de un presurizador. La presión arterial (PA) fue monitorizada a cada minuto y se administró 0,2 mg de metaraminol para cualquier diminución de PA, a partir del valor de control y 0,4 mg para diminución > 20%. La PA control fue definida como la media de tres valores sucesivos de PAS obtenidos antes de la expansión volémica y del bloqueo. Se estudió la velocidad de infusión de fluidos, incidencia de hipotensión arterial materna, náusea y vómito, consumo de metaraminol, índice de Apgar y pH de la arteria umbilical. RESULTADOS: La velocidad de administración de fluidos fue mayor en el Grupo 3 de que en los Grupos 1 y 2 (201 ± 61 vs 56 ± 13 y 59 ± 21 ml.min-1, p < 0,05). Los grupos fueron semejantes en relación a la incidencia de hipotensión arterial, náusea, vómito, consumo de metaraminol, índice de Apgar y pH de la arteria umbilical. CONCLUSIONES: La expansión volémica, realizada antes o después de la instalación de la raquianestesia, de manera rápida o lenta, no modifica el...

The incidence and management of priapism in Western Australia: a 16 year audit.

The objective of the study was to conduct a retrospective audit of patients who presented with priapism in Western Australia during the years 1985-2000. We searched the records of the teaching hospitals in metropolitan Perth and those of the Keogh Institute for Medical Research for the diagnostic code for priapism. A total of 82 episodes of priapism in 63 patients occurred over this 16 year period. In all, 62 episodes occurred after intracavernosal injections (ICI) and 20 were due to other causes. Treatment of priapism included simple aspiration of blood, intracavernosal injection of alpha-adrenergic agents and surgical shunt procedures. Priapism occurring outside the setting of ICI was more likely to require surgery; seven of 20 episodes. After ICI therapy, eight of 62 episodes required shunts. The use of prostaglandin E1 as the drug of choice in ICI therapy in 1989 led to a fall in the incidence of ICI-induced priapism. Priapism is a major side effect of ICI therapy and an uncommon, although important, side effect of other conditions. The incidence of priapism has fallen with the introduction of prostaglandin E1 monotherapy as the favoured drug for ICI therapy of erectile failure.

Anaphylactic or anaphylactoid reactions in patients undergoing cardiac surgery.

OBJECTIVE: To examine the clinical features, treatment, and outcome of anaphylactic and anaphylactoid reactions during cardiac surgery. DESIGN: Retrospective descriptive study. SETTING: A specialized referral anesthetic allergy clinic at a university teaching hospital. PARTICIPANTS: Twenty-three cardiac surgical patients referred after reactions resembling anaphylaxis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The database of the anesthetic allergy clinic was examined, and the data for patients who developed anaphylactic or anaphylactoid reactions were collated and summarized. Twenty-three cardiac surgical patients who experienced signs of anaphylactic or anaphylactoid reactions during anesthesia and surgery from 8 cardiac surgical centers in a major city were referred to the clinic. Cephalosporin antibiotics (30%) and gelatin solutions (Hemaccel) (26%) were the most common (56%) causes of the reactions. Most reactions occurred before the start of cardiopulmonary bypass. Although metaraminol was the first vasopressor used in 18 of 23 patients, it was not effective in 14 patients. Response to epinephrine was immediate and effective in 88% of cases. Rapid placement onto cardiopulmonary bypass facilitated a good outcome and permitted all but one operation to proceed as planned. No intraoperative or postoperative deaths were recorded. CONCLUSION: Of the anaphylactic and anaphylactoid reactions, 60% occurred before cardiopulmonary bypass, and these were caused by antibiotics and gelatin solution. The results from this limited database showed that cardiac surgery proceeded without complications after cardiovascular collapse caused by anaphylactic or anaphylactoid reactions. Rapid institution of cardiopulmonary bypass may be life-saving and should be considered.

The effect of prophylactic metaraminol on systemic hypotension caused by induction of anaesthesia with propofol in patients over 55 years old.

We conducted a double-blind, randomised, placebo-controlled study evaluating the efficacy of prophylactic metaraminol for preventing propofol-induced hypotension. Thirty patients aged 55-75 years undergoing general anaesthesia were randomly allocated to receive either metaraminol 0.5 mg or saline before administration of fentanyl 1 microg.kg(-1) and propofol 2 mg.kg(-1). Induction of anaesthesia was associated with a decrease in mean and systolic arterial pressure in both groups (p = 0.0001). However, there was no significant difference between the two groups. These results show that prophylactic use of metaraminol 0.5 mg does not prevent the decrease in blood pressure following fentanyl and propofol induction in older patients.