The epidural electric stimulation test does not predict local anesthetic spread or consumption in labour epidural analgesia.

PURPOSE: The epidural electrical stimulation test (EEST) is a highly specific and sensitive test for confirming placement of the epidural catheter in the epidural space. The purpose of this study was to investigate if the EEST could predict the spread and consumption of local anesthetic solutions during labour epidural analgesia. METHODS: This observational study was conducted in labouring parturients requesting epidural analgesia. The EEST was performed after the epidural catheter placement (T0) and repeated five minutes after a test dose with 2% lidocaine 3 mL (T1). The minimum current required to elicit the motor response at each time point was recorded. A loading dose of 0.125% bupivacaine 10 mL and fentanyl 50 µg was administered and followed by patient-controlled epidural analgesia with 0.0625% bupivacaine and fentanyl 2 µg·mL(-1) (baseline infusion 10 mL·hr(-1), bolus dose 5 mL, lockout interval ten minutes, maximum dose 20 mL·hr(-1)). The primary outcome was the correlation between the current required to elicit motor responses at T0 and T1 and the consumption of bupivacaine in the first two hours of epidural administration. The secondary outcomes included the muscle contraction patterns determined by the EEST and the incidence of failed, inadequate, or asymmetric blocks. RESULTS: The study was conducted in 102 parturients. The mean electric current required to elicit muscle response was 4.43 mA (range 1-10 mA) at T0, 5.97 mA (range 1-14 mA) at T1, and the mean Δ (T1-T0) current was 1.54 mA (range 0-8 mA). There was no correlation between either the mean baseline current required or the Δ (T1-T0) current and the total bupivacaine consumption at two hours. The incidence of inadequate blocks at two hours was 18%; however, none of the catheters required replacement. Unilateral left (34%) or right (31%) leg contraction was the most frequent pattern elicited by the EEST. CONCLUSIONS: The EEST shows a wide range of electrical current requirements and elicits a variety of muscle twitch patterns on the lower limbs. Although it confirms the epidural placement of the catheter, the EEST cannot be used to predict the spread or consumption of the local anesthetic solution during labour epidural analgesia.

Non-invasive hemodynamic assessment of non-pregnant, healthy pregnant and preeclamptic women using bioreactance. [corrected].

BACKGROUND AND OBJECTIVES: We compared hemodynamic profiles of healthy and mildly preeclamptic pregnant women at term, as well as those of non-pregnant controls, using a new non-invasive cardiac output monitor (NICOM) based on bio-reactance. METHODS: We studied healthy term pregnant women at term (Preg, n = 10), mildly preeclamptic pregnant women at term (PregPE, n = 10), and healthy non-pregnant female volunteers (NonPreg, n = 10). With the subjects in the semi left lateral position, 4 electrodes of the NICOM device were applied to their chest wall, followed by a 15-minute rest period. Hemodynamic variables, including the systolic (SBP), diastolic (DPB) and mean arterial (MAP) pressures, as well as the heart rate (HR), stroke volume (SV), total peripheral resistance (TPR), cardiac output (CO), cardiac power output (CPO), and ventricular ejection time (VET) were then monitored for 15 minutes. RESULTS: The Preg and NonPreg groups showed similar hemodynamic profiles, except for a shorter VET in the Preg group (213.3 ± 19.3 ms versus 265.0 ± 28.8 ms, p < 0.001). The PregPE group showed higher SBP, DBP and MAP, as well as CPO (145.5 ± 12.6 mmHg; 94.5 ± 9.1 mmHg; 111.5 ± 9.8 mmHg; 1.6 ± 0.3 watts), compared to both the Preg (114 ± 12.1 mmHg; 71.7 ± 8.4 mmHg; 85.9 ± 9.3 mmHg; 1.1 ± 0.3 watts) and NonPreg (101.2 ± 11.9 mmHg; 66.7 ± 10.4 mmHg; 78.1 ± 10.6 mmHg; 1.0 ± 0.2 watts) groups. The PregPE group showed higher HR, CO, and TPR, and shorter VET (85.4 ± 8.4 beats.min⁻¹; 6.6 ± 0.7 L.min⁻¹; 1,369.9 ± 173.5 dyne.sec.cm⁻5, 221.6 ± 22.4 ms) compared to the NonPreg group (67.9 ± 9.5 beats.min⁻¹; 5.6 ± 0.7 L.min⁻¹; 1,136.9 ± 149.8 dyne.sec.cm⁻5, 265.0 ± 28.8 ms). CONCLUSIONS: The NICOM device is simple to use, operator independent, and provides clear and consistent monitoring signals. The output identified distinct hemodymamic profiles that are consistent with the findings of more invasive existing methods.

Avaliação hemodinâmica não invasiva de mulheres não grávidas, gestantes saudáveis e gestantes com pré-eclâmpsia usando biorreatância / Non-invasive hemodynamic assessment of non-pregnant, healthy pregnant and preeclamptic women using bio-reactance / Evaluación hemodinámica no invasiva de mujeres no embarazadas, embarazadas sanas y embarazadas con preeclampsia usando biorreactancia

JUSTIFICATIVA E OBJETIVOS: Comparamos os perfis hemodinâmicos de gestantes saudáveis e com pré-eclâmpsia leve, a termo, assim como de controles saudáveis não grávidas, usando um novo monitor de débito cardíaco não invasivo (NICOM, do inglês) baseado na biorreatância. MÉTODOS: Estudamos gestantes saudáveis a termo (Preg, n = 10), gestantes a termo com pré-eclâmpsia leve (PregPE, n = 10) e mulheres saudáveis não grávidas (NonPreg, n = 10). Com as pacientes na posição de semidecúbito lateral esquerdo, 4 eletrodos do NICOM foram colocados na parede do tórax. Essa colocação foi seguida de um período de descanso de 15 minutos. Variáveis hemodinâmicas, incluindo pressão arterial sistólica (PAS), diastólica (PAD) e média (PAM), assim como frequência cardíaca (FC), volume sistólico (VS), resistência periférica total (RPT), débito cardíaco (DC), potência cardíaca (PC) e tempo de ejeção ventricular (TEV) foram monitorados por 15 minutos. RESULTADOS: Os grupos Preg e NonPreg apresentaram perfis hemodinâmicos semelhantes, exceto por um TEV mais curto no grupo Preg (213,3 ± 19,3 ms versus 265,0 ± 28,8 ms, p < 0,001). O grupo PregPE apresentou PAS, PAD e PAM mais elevadas, assim como PC (145,5 ± 12,6 mmHg; 94,5 ± 9,1 mmHg; 111,5 ± 9,8 mmHg; 1,6 ± 0,3 watts) quando comparado com os grupos Preg (114 ± 12,1 mmHg; 71,2 ± 8,4 mmHg; 85,9 ± 9,3 mmHg; 1,1 ± 0,3 watts) e NonPreg (101,2 ± 11,9 mmHg; 66,7 ± 10,4 mmHg; 78,1 ± 10,6 mmHg; 1,0 ± 0,2 watts). O grupo Preg apresentou FC, DC e RPT maiores e TEV mais curto (85,4 ± 8,4 batimentos.min-1; 6,6 ± 0,7 L.min-1; 1.369,9 ± 173,5 dina.seg.cm-5, 221,6 ± 22,4 ms) quando comparado ao grupo NonPreg (67,9 ± 9,5 batimentos.min-1; 5,6 ± 0,7 L.min-1; 1.136,9 ± 149,8 dina.seg.cm-5, 265,0 ± 28,8 ms). CONCLUSÕES: O NICOM é um equipamento fácil de ser usado, que independe do operador e fornece sinais de monitoramento claros e consistentes. A avaliação identificou perfis hemodinâmicos distintos e consistentes com os achados obtidos com métodos mais invasivos.

BACKGROUND AND OBJECTIVES: We compared hemodynamic profiles of healthy and mildly preeclamptic pregnant women at term, as well as those of non-pregnant controls, using a new non-invasive cardiac output monitor (NICOM) based on bio-reactance. METHODS: We studied healthy term pregnant women at term (Preg, n = 10), mildly preeclamptic pregnant women at term (PregPE, n = 10), and healthy non-pregnant female volunteers (NonPreg, n = 10). With the subjects in the semi left lateral position, 4 electrodes of the NICOM device were applied to their chest wall, followed by a 15-minute rest period. Hemodynamic variables, including the systolic (SBP), diastolic (DPB) and mean arterial (MAP) pressures, as well as the heart rate (HR), stroke volume (SV), total peripheral resistance (TPR), cardiac output (CO), cardiac power output (CPO), and ventricular ejection time (VET) were then monitored for 15 minutes. RESULTS: The Preg and NonPreg groups showed similar hemodynamic profiles, except for a shorter VET in the Preg group (213.3 ± 19.3 ms versus 265.0 ± 28.8 ms, p < 0.001). The PregPE group showed higher SBP, DBP and MAP, as well as CPO (145.5 ± 12.6 mmHg; 94.5 ± 9.1 mmHg; 111.5 ± 9.8 mmHg; 1.6 ± 0.3 watts), compared to both the Preg (114 ± 12.1 mmHg; 71.7 ± 8.4 mmHg; 85.9 ± 9.3 mmHg; 1.1 ± 0.3 watts) and NonPreg (101.2 ± 11.9 mmHg; 66.7 ± 10.4 mmHg; 78.1 ± 10.6 mmHg; 1.0 ± 0.2 watts) groups. The PregPE group showed higher HR, CO, and TPR, and shorter VET (85.4 ± 8.4 beats.min-1; 6.6 ± 0.7 L.min-1; 1,369.9 ± 173.5 dyne.sec.cm-5, 221.6 ± 22.4 ms) compared to the NonPreg group (67.9 ± 9.5 beats.min-1; 5.6 ± 0.7 L.min-1; 1,136.9 ± 149.8 dyne.sec.cm-5, 265.0 ± 28.8 ms). CONCLUSIONS: The NICOM device is simple to use, operator independent, and provides clear and consistent monitoring signals. The output identified distinct hemodymamic profiles that are consistent with the findings of more invasive existing methods.

JUSTIFICATIVA Y OBJETIVOS: Comparamos los perfiles hemodinámicos de embarazadas sanas y con preeclampsia ligera a término, como también los controles sanos de las no embarazadas, usando un nuevo monitor de débito cardíaco no invasivo (NICOM, del inglés), con base en la biorreactancia. MÉTODOS: Estudiamos embarazadas sanas a término (Embarazadas, n = 10), embarazadas a término con preeclampsia ligera (EmbarazadasPE, n = 10) y mujeres sanas no embarazadas (No Embarazadas, n = 10). Con las pacientes en posición de semidecúbito lateral izquierdo, 4 electrodos del NICOM fueron colocados en la pared del tórax. Esa colocación fue secundada por un período de descanso de 15 minutos. Variables hemodinámicas, incluyendo presión arterial sistólica (PAS), diastólica (PAD) y promedio (PAM), como también la frecuencia cardíaca (FC), volumen sistólico (VS), resistencia periférica total (RPT), débito cardíaco (DC), potencia cardíaca (PC) y tiempo de eyección ventricular (TEV), fueron monitorizados por 15 minutos. RESULTADOS: Los grupos Embarazada y No Embarazada, presentaron perfiles hemodinámicos parecidos, excepto por un TEV más corto en el grupo Embar. (213,3 ± 19,3 ms versus 265,0 ± 28,8 ms, p < 0,001). El grupo Embar.PE presentó PAS, PAD y PAM más elevados, y PC (145,5 ± 12,6 mmHg; 94,5 ± 9,1 mmHg; 111,5 ± 9,8 mmHg; 1,6 ± 0,3 watts), cuando se comparó con los grupos Embar. (114 ± 12,1 mmHg; 71,2 ± 8,4 mmHg; 85,9 ± 9,3 mmHg; 1,1 ± 0,3 watts) y No Embarazadas (101,2 ± 11,9 mmHg; 66,7 ± 10,4 mmHg; 78,1 ± 10,6 mmHg; 1,0 ± 0,2 watts). El grupo Embarazada presentó FC, DC y RPT más altos y TEV más corto (85,4 ± 8,4 latidos.min-1; 6,6 ± 0,7 L.min-1; 1.369,9 ± 173,5 dina.seg.cm5, 221,6 ± 22,4 ms) cuando se le comparó con el grupo No Embarazadas (67,9 ± 9,5 latidos.min-1; 5,6 ± 0,7 L.min-1; 1.136,9 ± 149,8 dina.seg.cm5, 265,0 ±28,8 ms). CONCLUSIONES: El NICOM es un equipo fácil de ser usado, que no depende del operador y que suministra señales de monitoreo claras y consistentes. La monitorización identificó perfiles hemodinámicos distintos y consistentes con los hallazgos de los métodos más invasivos existentes.