Ian Kaufman

Peripartum cardiomyopathy and thromboembolism; anesthetic management and clinical course of an obese, diabetic patient.

PurposeTo describe the anesthetic management and clinical course of a patient with peripartum cardiomyopathy. We highlight the frequent occurrence of thromboembolic morbidity in this group of parturients, emphasizing the need for early consideration of prophylactic anticoagulation.Clinical featuresA 38-yr-old, diabetic, obese parturient was admitted with pulmonary edema and severe orthopnea at 31 weeks gestation. The respiratory rate was 44 breaths· min−1, blood pressure 110/70 mmHg, pulse 120 beats· min−1 and rales were heard in both lung fields. The diagnosis of peripartum cardiomyopathy was made based on sinus tachycardia with no evidence of ischemia on the electrocardiogram, and global left ventricular hypokinesis with an ejection fraction of 40–45% noted on transthoracic echocardiography, Cesarean delivery was planned to improve maternal respiratory status and hemodynamics. General anesthesia with invasive monitoring was planned, and surgery and anesthesia proceeded uneventfully. Less than 24 hr postoperatively, she sustained a thrombotic cerebral infarct leaving her hemiparetic and dysarthric. Subsequent investigations revealed a thrombophilic state due to elevated anticardiolipin antibody.ConclusionGeneral anesthesia is an acceptable option in parturients with heart failure secondary to cardiomyopathy, Thromboembolic complications are common, and early consideration should be given to prophylactic anticoagulation.RésuméObjectifDécrire la prise en charge anesthésique et l’évolution clinique d’une patiente présentant une cardiomyopathie périnatale. Souligner l’occurrence fréquente de morbidité thromboembolique dans ce groupe de parturientes et insister sur la nécessité d’une prophylaxie avec des anticoagulants.Éléments cliniquesUne parturiente de 38 ans, obèse et diabétique, a été admise souffrant d’œdème pulmonaire et d’orthopnée sévère à 31 sem de grossesse. La fréquence respiratoire était de 44 respirations· min−1, la tension artérielle de 110/70 mmHg, le pouls de 120 battements· min−1 et des râles étaient perçus dans les deux champs pulmonaires. Le diagnostic de cardiomyopathie périnatale a été établi, fondé sur la tachycardie sinusaie, sans évidence d’ischémie à l’électrocardiogramme, et d’hypokinésie ventriculaire gauche comportant une fraction d’éjection de 40–45 % notée à l’échocardiographie transthoracique. Une césarienne a été décidée afin d’améliorer l’état respiratoire et l’hémodynamique de la mère. L’anesthésie générale accompagnée d’un monitorage effractif a été utilisée pendant l’opération qui s’est bien déroulée. Moins de 24 h après la césarienne, la mère a subi un infarctus cérébral thrombotique qui a entraîné hémiparésie et dysarthrie. Des examens ultérieurs ont révélé un état thrombophilique causé par des anticorps anticardiolipine élevés.ConclusionL’anesthésie générale constitue une option acceptable chez des parturientes présentant une insuffisance cardiaque secondaire à une cardiomyopathie. Des complications thromboemboliques sont fréquentes et il faudrait rapidement administrer des anticoagulants préventifs.

Autonomic Nervous System Response to Epidural Analgesia in Laboring Patients by Wavelet Transform of Heart Rate and Blood Pressure Variability

Background:Epidurals are effective in relieving labor pain but result in a sympathectomy that may compromise maternal hemodynamic stability and fetal perfusion. Decreases in blood pressure and heart rate can be corrected, but markers of autonomic activity would be useful to predict and prevent such changes. The goal of this study was to find markers describing the changes in autonomic nervous system activity with epidural anesthesia in laboring patients. Methods:The authors analyzed heart rate variability and blood pressure variability in 13 laboring patients using wavelet transform, a time-frequency analysis that accommodates rapid changes in autonomic activity. Heart rate and blood pressure variability were obtained 5 min before and 10 min after injection of 20 ml bupivacaine, 0.125%, and 50 &mgr;g fentanyl in the epidural space. Results:Blood pressure and heart rate were not affected by epidural analgesia. However, high-frequency power of heart rate variability increased after epidural (increase in parasympathetic drive). The ratio of low-frequency:high-frequency power of heart rate variability decreased. High- and low-frequency power of blood pressure variability decreased (decrease in sympathetic outflow). Conclusions:Indices of parasympathetic and sympathetic activity after neuraxial blockade in laboring patients can be obtained by analysis of both heart rate variability and blood pressure variability. The analysis by wavelet transform can discern changes in autonomic activity when values of blood pressure and heart rate do not vary significantly. Whether this technique could be used to predict and prevent hemodynamic compromise after neuraxial blockade merits further studies.

Maternal factors implicated in fetal bradycardia after combined spinal epidural for labour pain.

Background and objective: Combined spinal epidural analgesia is effective for fast relief of severe labour pain but has been associated with worrisome decreases in fetal heart rate. Since the reasons for this phenomenon remain elusive, some anaesthesiologists may abstain from using this technique. We postulated that factors unrelated to the neuraxial technique could play a role in the decrease in fetal heart rate. To our knowledge, no prospective study has previously looked into this possibility. Methods: We collected prospective data on 223 consecutive patients who received combined spinal epidural analgesia (123) or epidural analgesia (100). Maternal blood pressure, analogue pain scores, exogenous infusion of oxytocin, cervical dilatation, maternal age, parity and ethnicity were collected and correlated with the occurrence of decreases in fetal heart rate post combined spinal epidural. Results: Univariate analysis showed a correlation between the incidence of fetal bradycardia and higher maternal pain scores, older maternal age, and combined spinal epidural analgesia. Multivariate analysis revealed that only pain scores and maternal age were independent predictors of fetal bradycardia post neuraxial blockade. Conclusions: Maternal pain scores and older maternal age are factors unrelated to the neuraxial technique that are independent predictors of fetal bradycardia after neuraxial analgesia for labour.

Heart rate and blood pressure variability as markers of sensory blockade with labour epidural analgesia

PurposeTo evaluate the correlation between the progression of somatosensory blockade and changes in autonomic outflow following the onset of labour epidural analgesia.MethodsTwelve labouring parturients consented to participate in the study. Baseline electrocardiogram, blood pressure (BP) and respiratory rate were recorded for ten minutes. The epidural consisted of 0.125% bupivacaine with 50 μg of fentanyl (total volume 20 mL). Measurements were repeated for ten minutes after initiation of the block. The level of sensory block was measured bilaterally with loss of sensation to ice at two-minute intervals. Wavelet transform was used to obtain heart rate (HR) and BP variability every two minutes following the loading dose of epidural medication. High frequency power of HR variability was used to assess changes in parasympathetic activity. The total power of BP variability was used to assess changes in sympathetic activity. A nonparametric repeated measures ANOVA was used for the variability data, and a Spearman rank correlation test was used to evaluate the relationship between the sensory block and HR and BP variability.ResultsThe sensory block progressed to T9 at ten minutes post-epidural and was the mirror image of the decrease in total power of BP variability. High frequency power of HR variability increased to a plateau at six minutes post-epidural. A significant correlation was found between the increase in sensory block and the observed decrease in BP variability (r = -1.000,P = 0.0028).ConclusionIn this study of labouring parturients, BP variability correlated with the progression of both sympathetic and somatosensory block following epidural anesthesia, while HR variability was shown to be a surrogate marker of increased parasympathetic activity.RésuméObjectifÉvaluer la corrélation entre la progression du bloc somato-sensitif et les changements du débit autonome après le début de l’analgésie péridurale pour le travail obstétrical.MéthodeDouze parturientes en travail ont accepté de participer à cette étude. Les données de base d’électrocardiogramme, de tension artérielle (TA) et de fréquence respiratoire ont été enregistrées durant dix minutes. La péridurale était constituée de 0,125 % de bupivacaïne avec 50 μg de fentanyl (volume total 20 mL). Les mesures ont été reprises pendant dix minutes après le début du bloc. Le niveau du bloc sensitif a été mesuré bilatéralement par la perte de sensation au froid (glace) à des intervalles de deux minutes. La transformée par ondelettes a été utilisée pour obtenir la variabilité de la fréquence cardiaque (FC) et de la TA toutes les deux minutes après l’administration de la dose de péridurale. La puissance à haute fréquence de la variabilité de la TA a été utilisée pour évaluer les changements de l’activité parasympathique. La puissance totale de la variabilité de la TA a servi à évaluer les changements de l’activité sympathique. Une ANOVA pour mesures répétées non paramétriques a été utilisée pour les données de variabilité, et un test de corrélation de rang de Spearman a servi à l’évaluation de la relation entre le bloc sensitif et la variabilité de FC et de TA.RésultatsDix minutes après la péridurale, le bloc sensitif a progressé jusqu’à T9 et a reflété la diminution de la puissance totale de variabilité de TA. La puissance de la haute fréquence de la variabilité de FC a augmenté jusqu’à un plateau six minutes après la péridurale. Une corrélation importante a été notée entre l’augmentation du bloc sensitif et la diminution observée de variabilité de TA (r) = - 1,000, P = 0, 0028).ConclusionDans cette étude portant sur des parturientes en travail, la variabilité de la TA fut associée à la progression des blocs sympathique et somato-sensitif suite à l’anesthésie péridurale, et il a été démontré que la variabilité de la FC est un indicateur indirect d’une activité parasympathique accrue.