ABSTRACT
Abstract I report a case of hypotension and bradycardia before spinal anesthesia in a pregnant woman with mild to moderate hypertension treated with nifedipine and methyldopa, scheduled for an elective cesarean delivery. She had the history of neurally-mediated syncopes. Two main factors (increased vagal tone and adverse effects of antihypertensive drugs) could explain the hypotension and bradycardia before spinal anesthesia. Monitoring allowed recognizing the problem and corrected it. Thus, it was avoided a disaster in anesthesia, as hemodynamic changes after spinal anesthesia, they would have joined to previous hypotension and bradycardia, which would have caused even a cardiac arrest.
Resumo Relato de um caso de hipotensão e bradicardia antes da raquianestesia em uma mulher grávida com hipertensão leve a moderada tratada com nifedipina e metildopa, programada para parto cesáreo eletivo. A paciente apresentava história de síncopes neuralmente mediadas. Dois fatores principais (aumento do tônus vagal e efeitos adversos de medicamentos anti-hipertensivos) poderiam explicar a hipotensão e bradicardia antes da raquianestesia. O monitoramento permitiu reconhecer o problema e corrigi-lo. Dessa forma, foi evitado um desastre em anestesia; assim como as alterações hemodinâmicas após a raquianestesia, esses fatores teriam se juntado à hipotensão e bradicardia anterior, o que poderia até ter causado uma parada cardíaca.
Subject(s)
Humans , Female , Pregnancy , Adult , Pregnancy Complications, Cardiovascular/diagnosis , Bradycardia/complications , Bradycardia/diagnosis , Cesarean Section , Elective Surgical Procedures , Hypertension, Pregnancy-Induced , Hypotension/complications , Hypotension/diagnosis , Anesthesia, Obstetrical , Anesthesia, Spinal , Preoperative PeriodABSTRACT
BACKGROUND: Oxygen increases the cardiac vagal tone, blood pressure, systemic vascular resistance and vascular tone in healthy adults.This study assessed the autonomic tone according to different oxygen flow rates via different types of masks with using the heart rate variability (HRV) in the PACU after total intravenous anesthesia (TIVA). METHODS: We prospectively studied 27 patients after TIVA in the PACU.The 5 L group received oxygen via a simple mask with an oxygen rate of 5 L/min and the 10 L group received oxygen via a mask with a reservoir bag at a rate of 10 L/min in the PACU. We evaluated the HRV at the point of stabilization before anesthesia (BL), 5 min in the PACU (PACU 5), 30 min in the PACU (PACU 30) and 60 min in the PACU (PACU 60). RESULTS: In the 5 L group, the nuHF was increased to 42.4 +/- 24.2 at 60 min in the PACU as compared with 27.1 +/- 19.1 at 5 min in the PACU.In the 5 L group, the LFHFr was decreased to 2.3 +/- 2.1 at PACU 60 as compared with 6.6 +/- 9.7 at PACU 5 and the nuLF was decreased to 56.9 +/- 23.2 at PACU 60 as compared with 72.9 +/- 19.0 at PACU 5.There were no significant changes between the two groups at PACU 5, PACU 30 and PACU 60.The oxygen saturation was increased at PACU 60 compared with PACU 5 in the two groups. CONCLUSIONS: These finding indicates that 1 h of oxygen administration with 5 L/min during emergence from anesthesia increased the relative vagal tone, and the arterial blood pressure is stable irrespective of the oxygen flow rate.
Subject(s)
Humans , Anesthesia , Anesthesia, Intravenous , Arterial Pressure , Blood Pressure , Heart , Heart Rate , Masks , Oxygen , Prospective Studies , Vascular ResistanceABSTRACT
The aim of the study was to investigate the role of spectral analysis of heart rate variability (HRV) for assessing the type and degree of sympathovagal imbalance (SVI) and their link to cardiovascular morbidities in thyroid dysfunctions. Forty-five female subjects (15 control subjects and freshly diagnosed untreated 15 hypothyroid and 15 hyperthyroid patients) were recruited for the study. Thyroid profile, body mass index (BMI), basal heart rate (BHR), blood pressure (BP) and spectral indices of HRV (TP, LFnu, HFnu and LF-HF ratio, mean RR, SDNN and RMSSD) were assessed in all the three groups. LF-HF ratio was correlated with thyroid profile, BMI, BHR and BP. SVI was more prominent in hyperthyroid (P<0.001) compared to hypothyroid (P<0.05) subjects. LF-HF ratio was correlated with thyroid profile in both hypo and hyperthyroid subjects; but correlation with BHR and BP was significant only in hyperthyroidism. Though the SVI was found to be due to both vagal withdrawal and sympathetic activation, especially in hyperthyroidism, contribution by vagal inhibition was prominent. Vagal inhibition contributes significantly to SVI in thyroid dysfunctions, especially in hyperthyroidism. As the present study indicates poor cardiovascular health due to vagal inhibition in patients suffering from thyroid dysfunctions, attempt should be made to improve vagal tone especially in hyperthyroid subjects to attain a stable sympathovagal and cardiovascular homeostasis.
ABSTRACT
BACKGROUND: This study was designed to assess the effects of rilmenidine on the autonomic nervous system, and to evaluate whether it prevents bupivacaine-induced cardiovascular toxicity during intravenous bupivacaine infusion in anesthetized cats. METHODS: Thirty male cats were randomly divided into a control group (n = 15) and a rilmenidine group (n = 15). Following the injection of rilmenidine (10microgram/kg), systolic blood pressures (SBP) and R-R intervals (RRI) were recorded for 5 minutes. Then power spectral analyses of the SBP and RRI, and transfer function analysis were conducted to evaluate the autonomic nervous system. During the infusion of bupivacaine (0.5 mg/kg/min), blood pressures, heart rates, times to reach each events, and bupivacaine doses were measured at the first QRS modification, the first dysrhythmia, at 25% (HR25) and 50% reductions in baseline heart rate, and at 25% and 50% reductions in baseline mean arterial pressure and at final systole. RESULTS: The high frequency (HF) power of heart rate variability (HRV) was significantly elevated in the rilmenidine group versus the control group. Magnitude HF was significantly higher in the rilmenidine group than in the control group. The onset of dysrhythmia correlated significantly with the HFs of HRV and baroreflex sensitivity (BRS). Except for HR25, the rilmenidine group showed significantly higher bupivacaine doses and delayed event onsets versus the control group. CONCLUSIONS: We suggest that pretreatment with rilmenidine delays the onset of dysrhythmia by increasing vagal tone and BRS and by reducing cardiovascular toxicity when bupivacaine is infused continuously to isoflurane anesthetized cats.
Subject(s)
Animals , Cats , Humans , Male , Arterial Pressure , Autonomic Nervous System , Baroreflex , Bupivacaine , Heart Rate , Isoflurane , SystoleABSTRACT
BACKGROUND: A poincare plot of the heart rate variability (HRV) allows for the quantitative display of the vagal tone in conscious humans. However, relatively little is known about standard deviation 1 (SD1) from the poincare plot reflecting the vagal tone and correlating with the high frequency (HF) spectral power of the HRV during general anesthesia. Thus, the association of SD1 from the poincare plot was examined, along with the HF spectral power of the HRV during general anesthesia. METHODS: Beat-to-beat electrocardiograms were recorded for 5 min in 23 patients (isoflurane group, n = 13; sevoflurane group, n = 10) before, during and after general anesthesia. The low frequency (LF) and HF spectral powers, the LF/HF ratio of the HRV and the SD1 and standard deviation 2 (SD2) from the poincare plot were calculated. RESULTS: Both the HF spectral power of the HRV and SD1 from the poincare plot were reduced following general anesthesia, but recovered thereafter. The recovery of both the HF spectral power and SD1 from the poincare plot in the sevoflurane group was faster than those in the isoflurane group. There were strong correlations between the HF spectral power and SD1 before, during and after anesthesia. CONCLUSIONS: These data suggest that the SD1 from the poincare plot is a useful and valid parameter for analysis of the vagal tone during general anesthesia.
Subject(s)
Humans , Anesthesia , Anesthesia, General , Electrocardiography , Heart Rate , Heart , IsofluraneABSTRACT
A descriptive exploratory design was used in this study to evaluate the effects of sponge bathing on physiological(heart rate, heart period, vagal tone, oxygen saturation, respiration) and behavioral responses in newly born 40 preterm infants from intensive care unit of S University Hospital in Seoul. Data has been collected from October, 1997 to March, 1999. The infants were between 27-33 weeks gestational age at birth, and were free of congenital defects. The subjects entered the protocol when they were medically stable (determined by initiation of feeding and discontinuation of all respiratory support) but still receiving neonatal intensive care. The infants' physiologic parameters were recorded a 10 - minute before, during, and after bathing. Continuous heart rate data were recorded on a notebook computer from the infant's EKG monitor. The data were digitized off-line on software(developed by Lee and Chang in Wavelet program) which detected the peak of the R wave for each heart beat and quantified sequential R-R intervals in msec(i.e. heart periods). Heart period data were edited to remove movement artifact. Heart period data were quantified as : 1) mean heart period; 2) vagal tone. Vagal tone was quantitfied with a noninvasive measure developed by Porges(1985) in Mxedit software. To determine behavioral status, tools were developed by Scafidi et al(1990) were used. Collected data were analyzed with the SPSS program using paried t-test, ANOVA, and Pearson correlation. The result were as follow. 1.The results of the ANOVAs indicated that vagal tone were signifcantly lower during bathing than baseline and post-bathing. There were significant differences in heart period and heart rate levels across the bathing. But the mean oxygen saturations and respirations were no differences. Also, there were no significant differences on behavioral sign, motor activity, behavioral distress, weight changes, morbidity, and hospitalization period. 2. To evaluate the relation between vagal tone and subsequent parameters, the two groups (the high group had 19 subjects and low group had 21subjects) were divided by the mean baseline vagal tone. Vagal tone measured prior to bathing were significantly associated with respiration before bathing, vagal tone during bathing, and the magnitude of change in both vagal tone. But, other subsequent reactivities were no differences in two groups. 3.Correlations were also calculated between vagal tone and the subsequent physiological reactivities from baseline through after- bathing. Correlations were significant between baseline vagal tone and baseline heart rate, between baseline vagal tone and baseline heart period, between baseline vagal tone and oxygen saturation after bathing. In summary, the bathing in this study showed a stressful stimulus on premature infants through there was significance in the physiological parameters. In addition, our study represents the documentation that vagal tone reactivity in response to clearly defined external stimulation provides an index of infant's status.
Subject(s)
Humans , Infant , Infant, Newborn , Artifacts , Baths , Congenital Abnormalities , Electrocardiography , Gestational Age , Heart , Heart Rate , Hospitalization , Infant, Premature , Intensive Care Units , Intensive Care, Neonatal , Motor Activity , Oxygen , Parturition , Porifera , Respiration , Seoul , Child HealthABSTRACT
Objetivo - Identificar os critérios mais valorizados par ao diagnóstico eletrocardiográfico de vagotomia na opiniäo de cardiologistas. Métodos - Questionário distribuído a 40 cardiologistas durante o 9§ Congresso brasileiro de Arritmias Cardíacas (Säo José do Rio Preto, SP). A amostra representou cerca de 15 por cento dos participantes e foi propositalmente viesada para incluir 70 por cento dos palestrantes e apresentadores de temas-livres, e excluir profissionais näo-médicos, a fim de aumentar a validade de conteúdo das respostas. Foi dividido em duas partes: 1ª de resposta espontânea, preenchida sem conhecimento da seguinte; e 2ª, de resposta induzida, onde foram apresentados, em ordem randômica, critérios de eletrocardiograma (ECG) da literatura. Nas duas partes, foi solicitado que as respostas seguissem uma escala decrescente de importância. Resultados - Na 1ª arte. 35 diferentes critérios foram apontados, mas somente 3 foram citados por mais de 25 por cento dos entrevistados: bradicardia sinusal (95 por cento), presença de onda T apiculada (30 por cento) e repolarizaçäo precoce (27,5 por cento). Na 2ª parte, o critério melhor classificado foi a bradicardia sinusal, seguido pelo supradesnível do ponto J e pelo supradesnível do segmento ST. Conclusäo. Entre cardiologistas com interesse em eletrocardiografia e arritmias cardíacas, com exceçäo da bradicardia sinusal, näo existe um claro consenso quanto ao grupo de critérios a serem valorizados para a identificaçäo vagotonia no ECG. Estudos adicionais säo necessários para validar objetivamente os critérios mais comuns identificados nesta pesquisa