Noradrenaline and dobutamine effects on the volume expansion with normal saline in rabbits subjected to hemorrhage.

PURPOSE:: To evaluate the effects of dobutamine (DB), noradrenaline (NA), and their combination (NADB), on volume retention in rabbits submitted to hemorrhage. METHODS:: Thirty six rabbits were randomly divided into 6 groups: SHAM, Control, Saline, DB, NA, DB+NA. All the animals, except for SHAM, were subjected to hemorrhage of 25% of the calculated blood volume. Control animals were replaced with their own blood. The other groups received NSS 3 times the volume withdrawn. The intravascular retention, hematocrit, diuresis, central venous pressure, mean arterial pressure, NGAL, dry-to-wet lung weight ratio (DTWR) and the lung and kidney histology were analyzed. RESULTS:: Replacement with NSS and NA, DB or NA+DB did not produce differences in the intravascular retention. After hemorrhage, the animals presented a significant decrease in the MAP and CVP, which were maintained until volume replacement. Regarding NGAL, dry-to-wet-lung-weight ratio, lung and kidney histology, there were no statistical differences between the groups. CONCLUSION:: The use of noradrenaline, dobutamine or their combination did not increase the intravascular retention of volume after normal saline infusion.

Effects of catecholamines on volemic replacement with saline solution and the impact on heart rate variability in rabbits subjected to hemorrhage. A study by spectral analysis.

PURPOSE: To verify the effects of different catecholamines on volemic expansion and on the autonomic nervous system in rabbits that were subjected to hemorrhage. METHODS: Twenty four rabbits subjected to hemorrhage (with a 25% loss of blood volume) and were randomly divided into four experimental groups: 1) HEMO Group underwent replacement with their own blood in an equal volume; 2) SS Group underwent replacement with saline solution (SS) in a volume that corresponded to three times the removed blood volume; 3) ISP Group underwent replacement with SS and isoprenaline; 4) FNL Group underwent replacement with SS and phenylephrine. Spectral Analysis of the heart rate and heart rate variability were performed from the recorded data. Hematocrit was measured throughout the experiment. RESULTS: Replacement with SS and an α- or ß-agonist did not produce differences in the intravascular retention compared to replacement with SS alone. An analysis of HRV showed that the FNL group maintained the LF/HF ratio better than ISP and SS. CONCLUSIONS: No difference in vascular retention when α- or ß- agonists were added to SS during post-hemorrhagic recovery. The animals in the FNL group maintained the integrity of the autonomic response within normal physiological standards during hemorrhagic stress.

Noradrenaline and dobutamine effects on the volume expansion with normal saline in rabbits subjected to hemorrhage

ABSTRACT PURPOSE: To evaluate the effects of dobutamine (DB), noradrenaline (NA), and their combination (NADB), on volume retention in rabbits submitted to hemorrhage. METHODS: Thirty six rabbits were randomly divided into 6 groups: SHAM, Control, Saline, DB, NA, DB+NA. All the animals, except for SHAM, were subjected to hemorrhage of 25% of the calculated blood volume. Control animals were replaced with their own blood. The other groups received NSS 3 times the volume withdrawn. The intravascular retention, hematocrit, diuresis, central venous pressure, mean arterial pressure, NGAL, dry-to-wet lung weight ratio (DTWR) and the lung and kidney histology were analyzed. RESULTS: Replacement with NSS and NA, DB or NA+DB did not produce differences in the intravascular retention. After hemorrhage, the animals presented a significant decrease in the MAP and CVP, which were maintained until volume replacement. Regarding NGAL, dry-to-wet-lung-weight ratio, lung and kidney histology, there were no statistical differences between the groups. CONCLUSION: The use of noradrenaline, dobutamine or their combination did not increase the intravascular retention of volume after normal saline infusion.

Effects of catecholamines on volemic replacement with saline solution and the impact on heart rate variability in rabbits subjected to hemorrhage. A study by spectral analysis

PURPOSE: To verify the effects of different catecholamines on volemic expansion and on the autonomic nervous system in rabbits that were subjected to hemorrhage. METHODS: Twenty four rabbits subjected to hemorrhage (with a 25% loss of blood volume) and were randomly divided into four experimental groups: 1) HEMO Group underwent replacement with their own blood in an equal volume; 2) SS Group underwent replacement with saline solution (SS) in a volume that corresponded to three times the removed blood volume; 3) ISP Group underwent replacement with SS and isoprenaline; 4) FNL Group underwent replacement with SS and phenylephrine. Spectral Analysis of the heart rate and heart rate variability were performed from the recorded data. Hematocrit was measured throughout the experiment. RESULTS: Replacement with SS and an α- or β-agonist did not produce differences in the intravascular retention compared to replacement with SS alone. An analysis of HRV showed that the FNL group maintained the LF/HF ratio better than ISP and SS. CONCLUSIONS: No difference in vascular retention when α- or β- agonists were added to SS during post-hemorrhagic recovery. The animals in the FNL group maintained the integrity of the autonomic response within normal physiological standards during hemorrhagic stress. .

[Postoperative analgesia for cesarean section: does the addiction of clonidine to subarachnoid morphine improve the quality of the analgesia?]. / Analgesia pós-operatória para cesariana: a adição de clonidina à morfina subaracnóidea melhora a qualidade da analgesia?

BACKGROUND AND OBJECTIVES: The mechanism of action of alpha2-adrenergic analgesia has been explored for more than one hundred years. The increased duration of the sensitive and motor blockades caused by clonidine is dose-dependent and has antinociceptive properties. The objective of this study was to evaluate whether the addition of 15 to 30 microg of clonidine to spinal anesthesia for cesarean sections with 0.5% hyperbaric bupivacaine (12.5 mg) and morphine (100 microg) improves the quality of postoperative analgesia. METHODS: We realized a prospective, randomized study that included 60 patients divided in 3 groups: BM - 0.5% hyperbaric bupivacaine (12.5 mg) and morphine (100 microg), BM15 - 0.5% hyperbaric bupivacaine (12.5 mg), morphine (100 microg), and clonidine (15 mg), and BM30 - 0.5% hyperbaric bupivacaine (12.5 mg), morphine (100 microg), and clonidine (30 microg), administered separately. In the perioperative period the use of ephedrine and the newborn's Apgar score were recorded. In the postoperative period, the pain was evaluated in the 12th h by the VAS, the length of time it took the patient to ask for analgesics, and the postoperative side effects, such as pruritus, nausea, vomiting, bradycardia, hypotension, and sedation. The values were considered significant when p < 0.05. RESULTS: The groups were homogenous. The use of ephedrine and the evaluation by the Apgar score did not show statistically significant differences among the different groups. The pain scores and the average time to start analgesia showed differences among the groups BM and BM15/BM30, and there were no differences regarding the incidence of postoperative side effects. CONCLUSIONS: The addition of clonidine to spinal anesthesia with 0.5% hyperbaric bupivacaine (12.5 mg) and morphine (100 microg) for cesarean section improved the quality of the postoperative analgesia without increasing the incidence of side effects. We suggest that the dose of 15 microg of clonidine should be used.

Analgesia pós-operatória para cesariana: a adição de clonidina à morfina subaracnóidea melhora a qualidade da analgesia? / Postoperative analgesia for cesarean section: does the addiction of clonidine to subarachnoid morphine improve the quality of the analgesia?

JUSTIFICATIVA E OBJETIVOS: O mecanismo de ação analgésica a2-adrenérgico tem sido explorado há mais de 100 anos. A clonidina aumenta de maneira dose-dependente a duração dos bloqueios sensitivo e motor e tem propriedades antinociceptivas. O objetivo desse estudo foi avaliar se a adição de clonidina na dose de 15 e 30 µg à raquianestesia, para cesariana, com bupivacaína hiperbárica a 0,5 por cento (12,5 mg) e morfina (100 µg), melhora a qualidade da analgesia pós-operatória. MÉTODO: Foi realizado um estudo prospectivo e aleatório com 60 pacientes divididas em três grupos: BM - bupivacaína hiperbárica a 0,5 por cento (12,5 mg) e morfina (100 µg), BM15 - bupivacaína hiperbárica a 0,5 por cento (12,5 mg), morfina (100 µg) e clonidina (15 µg) e BM30 - bupivacaína hiperbárica a 0,5 por cento (12,5 mg), morfina (100 µg) e clonidina (30 µg), administradas separadamente. No peri-operatório, foram anotados o consumo de efedrina e a avaliação do recém-nascido pelo índice de Apgar. No pós-operatório, a dor foi avaliada na 12ª h pela Escala Analógica Visual, o tempo para solicitação de analgésicos e efeitos colaterais pós-operatórios, como prurido, náuseas, vômitos, bradicardia, hipotensão arterial e sedação. Os valores foram considerados significativos quando p < 0,05. RESULTADOS: Os grupos foram homogêneos. O consumo de efedrina e a avaliação pelo índice de Apgar não exibiram diferença estatística significativa entre os grupos. Os escores de dor e o tempo médio de analgesia mostraram diferença entre os grupos BM e BM15/BM30 e não houve diferença com relação à incidência de efeitos colaterais pós-operatórios. CONCLUSÕES: A adição de clonidina na raquianestesia com bupivacaína hiperbárica a 0,5 por cento (12,5 mg) e morfina (100 µg) para cesariana, melhorou a qualidade da analgesia pós-operatória, sem aumentar a incidência de efeitos colaterais, sendo 15 µg de clonidina a dose sugerida.

Efeitos das catecolaminas sobre a reposição volêmica com solução fisiológica. Repercussão sobre a variabilidade da frequência cardíaca de coelhos submetidos à hemorragia: estudo por análise espectral / The effect of catecholamines over volemic reposition with saline solution and its effects on the heart rate variability on rabbits subjected to hemorrhage: research through spectral analysis

Efeitos das catecolaminas sobre a reposição volêmica com solução fisiológica. Repercussão sobre a variabilidade da frequência cardíaca de coelhos submetidos à hemorragia. Estudo por análise espectral. Verificar os efeitos de diferentes catecolaminas sobre a expansão volêmica e sobre o sistema nervoso autonômico em coelhos submetidos à hemorragia. Foram estudados 24 coelhos, submetidos à hemorragia (25% da volemia), distribuídos aleatoriamente em quatro grupos experimentais, conforme o tipo de reposição volêmica realizada. Grupo HEMO - reposição com o próprio sangue com volume igual ao retirado. Grupo SF - reposição com solução fisiológica (SF) em volume correspondente a três vezes o volume de sangue retirado. Grupo ISP - reposição com SF em volume correspondente a três vezes o volume de sangue retirado, e Isoprenalina na dose de 0,1g.kg-1.min-1, e Grupo FNL – reposição com SF em volume correspondente a três vezes o volume de sangue retirado, e Fenilefrina na dose de 3,0g.kg-1.min-1. Durante o experimento, foram monitoradas as seguintes variáveis: hematócrito (para avaliação da retenção intravascular da solução cristaloide), diurese, pressção venosa central (PVC) e pressão arterial média (PAM). Também foi feito o registro contínuo da onda da pressão arterial donde analisando-se o pico sistólico aferiu-se a variabilidade da frequência cardŠíaca (VFC) nos períodos correspondentes à: basal, hemorrágico, infusção de catecolaminas e controle pós-reposição volêmica...

The effect of catecholamines over volemic reposition with saline solution and its effects on the heart rate variability on rabbits subjected to hemorrhage. Research through Spectral Analysis. To check the effects of different catecholamines on the volemic expansion and on the autonomic nervous system of rabbits subjected to hemorrhage. 24 rabbits were studied, subjected to hemorrhage (25% volemia), randomly distributed in four experimental groups, according to the type of volemic reposition done. HEMO Group: Reposition administered with the animal’s own blood, in the same amount of blood taken out. Saline Solution (SS) Group: Reposition with SS, three times the amount of blood withdrawn. Isoprenaline (ISP) Group: Reposition with SS, three times the amount of blood taken out, and Isoprenaline at 0,1g.kg-1.min-1; and Phenylephrine (PHN) Group: Reposition with SS three times the amount of blood withdrawn, and Phenylephrine at 3,0g.kg-1.min- 1. During the experiment, the following variables were monitored: hematocrit (to evaluate intravascular retention of the crystalloid solution), diuresis, central venous pressure and medium blood pressure. The blood pressure curve was also checked and by examining the systolic peak, the heart rate variability was verified during these different stages: basal, hemorrhagic, catecholamine infusion and post volemic reposition control. The reposition done with SS mixed in agonist α or β catecholamine did not demonstrate differences in intravascular retention, when comparing to isolated reposition with SS...

Uso de morfina peridural para analgesia pós-operatória em cesarianas / The use of morphine for postoperative analgesia in cesarean section

No presente estudo foram analisadas a eficácia e a ocorrência de efeitos colaterais na associaçäo da bupivacaína com morfina, por via epidural, objetivando o controle do quadro álgico pós-operatório em pacientes submetidas a cesarianas eletivas. Sessenta pacientes ASA I e II, foram divididas em 4 grupos: A-bupivacaina, B-bupivacaína e morfina 1 mg, C-bupivacaína e morfina 3 mg. Foram analisados o tempo de analgesia pós-operatória (momento após a anestesia em que os analgésicos eram solicitados pelas pacientes) e a ocorrência de efeitos colaterais. A necessidade de analgésicos foi significativamente diferente (p<0,05) entre o grupo-controle A e os grupos C e D. Näo aconteceu depressäo respiratória, nem diferença significativa com relaçäo a náuseas e vômitos. O aparecimento de prurido foi maior nos pacientes do grupo D. Os autores concluem que a administraçäo de morfina com anestésicos locais, por via peridural, é um método promissor de analgesia pós-operatória. No entanto, os resultados obtidos näo permitem preconizar uma dose ideal, sugerindo a necessidade do uso de doses maiores.

Uso de morfina peridural em doses de 4 e 5 mg para analgésia pós-operatória em cesarianas / The use of epidural morphine in doses of 4 and 5 mg to postoperative analgesia for cesarian section

O presente estudo, tem por finalidade avaliar o uso da morfina em doses de 4 e 5 mg, associada à bupivacaína 125 mg com adrenalina 1/200000, administrada por via peridural, com objetivo de controlar o quadro álgico pós-operatório em cesariana. O estudo foi realizado em 90 pacientes, ASA I e II, submetidas a cesarianas eletivas, sob anestesia peridural com bupivacaína (125 mg a 0,5 por cento com adrenalina 1/200000) e morfina. As pacientes foram divididas em três grupos: A (Controle), B (Morfina 4 mg) e C (Morfina 5 mg). No pós-operatório, as pacientes foram observadas por um per[iodo de 48 horas, avaliando-se a necessidade de anlgésicos (momento em que os mesmos eram solicitados após a anestesia) e a presen;a de efeitos colaterais como: náuseas, vômitos, prurido, e depressäo respiratória (FR<10 incursöes por minuto(IRM)). A necessidade de analgésicos mostrou diferenças significativas (p<0,05) entre o grupo controle e os grupos B e C. Em relaçäo a efeitos colaterais, chama atençäo a menor incidência de prurido nas pacientes do grupo C. Näo ocorreu depressäo respiratória. Os autores concluem que 4 mg de morfina por via peridural mostram-se eficazes para analgesia pós-operatória em cesarianas. No entanto, como a técnica foi ineficaz no controle da dor em 100 por cento das pacientes, sugere-se que a associaçäo com outros métodos analgésicos possa ser mais eficiente.