Anesthetic requirements measured by bilateral bispectral analysis and femoral blockade in total knee arthroplasty / Necessidade de anestésicos avaliada com a análise do índice bispectral bilateral e bloqueio femoral em artroplastia total de joelho

Abstract Background and objectives A continuous peripheral nerve blockade has proved benefits on reducing postoperative morphine consumption; the combination of a femoral blockade and general anesthesia on reducing intraoperative anesthetic requirements has not been studied. The objective of this study was to determine the relevance of timing in the performance of femoral block to intraoperative anesthetic requirements during general anesthesia for total knee arthroplasty. Methods A single-center, prospective cohort study on patients scheduled for total knee arthroplasty, were sequentially allocated to receive 20 mL of 2% mepivacaine throughout a femoral catheter, prior to anesthesia induction (Preoperative) or when skin closure started (Postoperative). An algorithm based on bispectral values guided intraoperative anesthetic management. Postoperative analgesia was done with an elastomeric pump of levobupivacaine 0.125% connected to the femoral catheter and complemented with morphine patient control analgesia for 48 hours. The Kruskall Wallis and the chi-square tests were used to compare variables. Statistical significance was set at p < 0.05. Results There were 94 patients, 47 preoperative and 47 postoperative. Lower fentanyl and sevoflurane were needed intraoperatively in the Preoperative group; median values and range: 250 (100-600) vs 450 (200-600) µg and 21 (12-48) vs 32 (18-67) mL p = 0.001, respectively. There were no differences in the median verbal numeric rating scale values 4 (0-10) vs 3 (0-10); and in median morphine consumption 9 (2-73) vs 8 (0-63) mg postoperatively. Conclusions A preoperative femoral blockade is useful in decreasing anesthetic requirements in total knee arthroplasty surgery but no added effect in the postoperative analgesic control.

Resumo Justificativa e objetivos O bloqueio contínuo de nervos periféricos provou ser benéfico para reduzir o consumo de morfina no pós-operatório. A combinação de um bloqueio femoral e anestesia geral para reduzir a necessidade de anestésicos no intraoperatório ainda não foi avaliada. O objetivo deste estudo foi determinar a relevância do momento propício durante o bloqueio femoral para a necessidade de anestésicos no intraoperatório durante a anestesia geral para artroplastia total de joelho (ATJ). Métodos Estudo prospectivo de coorte de pacientes agendados para ATJ. Os pacientes foram sequencialmente alocados em grupos para receber mepivacaína a 2% (20 mL) durante a inserção do cateter femoral, antes da indução da anestesia (pré-operatório) ou no início do fechamento da pele (pós-operatório). Um algoritmo com base nos valores do BIS orientou o manejo da anestesia no intraoperatório. Analgesia no pós-operatório foi administrada via bomba elastomérica de levobupivacaína a 0,125% conectada ao cateter femoral e complementada com analgesia (morfina) controlada pelo paciente durante 48 horas. Os testes de Kruskall-Wallis e do qui-quadrado foram usados para comparar as variáveis. A significância estatística foi estabelecida em p < 0,05. Resultados Foram estudados 94 pacientes, 47 no pré-operatório e 47 no pós-operatório. Houve menos necessidade de fentanil e sevoflurano durante o período intraoperatório no grupo pré-operatório; medianas e variações dos valores: 250 (100-600) vs. 450 (200-600) µg e 21 (12-48) vs. 32 (18-67) mL p = 0,001, respectivamente. Não houve diferenças nas medianas dos valores das escalas de classificação numérica e verbal, 4 (0-10) vs. 3 (0-10), e nas medianas do consumo de morfina, 9 (2-73) vs. 8 (0-63) mg no pós-operatório. Conclusões O bloqueio femoral no pré-operatório é útil para diminuir a necessidade de anestésicos em ATJ, mas não tem efeito adicional no controle da analgesia no pós-operatório.

[Anesthetic requirements measured by bilateral bispectral analysis and femoral blockade in total knee arthroplasty]. / Necessidade de anestésicos avaliada com a análise do índice bispectral bilateral e bloqueio femoral em artroplastia total de joelho.

BACKGROUND AND OBJECTIVES: A continuous peripheral nerve blockade has proved benefits on reducing postoperative morphine consumption; the combination of a femoral blockade and general anesthesia on reducing intraoperative anesthetic requirements has not been studied. The objective of this study was to determine the relevance of timing in the performance of femoral block to intraoperative anesthetic requirements during general anesthesia for total knee arthroplasty. METHODS: A single-center, prospective cohort study on patients scheduled for total knee arthroplasty, were sequentially allocated to receive 20mL of 2% mepivacaine throughout a femoral catheter, prior to anesthesia induction (Preoperative) or when skin closure started (Postoperative). An algorithm based on bispectral values guided intraoperative anesthetic management. Postoperative analgesia was done with an elastomeric pump of levobupivacaine 0.125% connected to the femoral catheter and complemented with morphine patient control analgesia for 48hours. The Kruskall Wallis and the chi-square tests were used to compare variables. Statistical significance was set at p<0.05. RESULTS: There were 94 patients, 47 preoperative and 47 postoperative. Lower fentanyl and sevoflurane were needed intraoperatively in the Preoperative group; median values and range: 250 (100-600) vs 450 (200-600)µg and 21 (12-48) vs 32 (18-67)mL p=0.001, respectively. There were no differences in the median verbal numeric rating scale values 4 (0-10) vs 3 (0-10); and in median morphine consumption 9 (2-73) vs 8 (0-63)mg postoperatively. CONCLUSIONS: A preoperative femoral blockade is useful in decreasing anesthetic requirements in total knee arthroplasty surgery but no added effect in the postoperative analgesic control.

Protocolized hyperventilation enhances electroconvulsive therapy.

BACKGROUND: Hyperventilation is recommended in electroconvulsive therapy (ECT) to enhance seizures and to increase patients' safety. However, more evidence is needed regarding its effects and the optimum method of application. METHODS: This prospective study involving 21 subjects compared two procedures, protocolized hyperventilation (PHV) and hyperventilation as usual (HVau), applied to the same patient in two consecutive sessions. Transcutaneous partial pressure of carbon dioxide (TcPCO2) was measured throughout all sessions. Ventilation parameters, hemodynamic measures, seizure characteristics, and side effects were also explored. RESULTS: PHV resulted in lower TcPCO2 after hyperventilation (p=.008) and over the whole session (p=.035). The lowest TcPCO2 was achieved after voluntary hyperventilation. Changes in TcPCO2 from baseline showed differences between HVau and PHV at each session time-point (all p<.05). Between- and within-subjects factors were statistically significant in a general linear model. Seizure duration was greater in PHV sessions (p=.028), without differences in other seizure quality parameters or adverse effects. Correlations were found between hypocapnia induction and seizure quality indexes. LIMITATIONS: Secondary outcomes could be underpowered. CONCLUSIONS: PHV produces hypocapnia before the stimulus, modifies patients' TcPCO2 values throughout the ECT session and lengthens seizure duration. Voluntary hyperventilation is the most important part of the PHV procedure with respect to achieving hypocapnia. A specific ventilation approach, CO2 quantification and monitoring may be advisable in ECT. PHV is easy to apply in daily clinical practice and does not imply added costs. Ventilation management has promising effects in terms of optimizing ECT technique.

Acute bilateral ECT in a depressed patient with a hip-aztreonam-spacer and subsequent maintenance ECT after prosthesis collocation.

ABSTRACT Electroconvulsive Therapy (ECT) has been demonstrated to be a safe and effective treatment for geriatric depression, although its application might be challenging when medical comorbidities exist. The present case reports a 78-year-old man diagnosed with recurrent unipolar major depressive disorder (MDD), who presented with a severe depressive episode with psychotic features (DSM IV). He successfully received a course of bitemporal (BT) ECT with a hip-aztreonam-spacer due to a hip fracture that occurred during hospitalization. This was followed by maintenance ECT (M-ECT) with a recent prosthesis collocation. This particular case illustrates the importance of a multidisciplinary approach in geriatric patients with somatic complications receiving ECT.