[Correlation between the inspired fraction of oxygen, maternal partial oxygen pressure, and fetal partial oxygen pressure during cesarean section of normal pregnancies]. / Correlação entre a fração inspirada de oxigênio, a pressão parcial de oxigênio materno e a pressão parcial de oxigênio fetal durante parto cesáreo em gestações normais.

BACKGROUND AND OBJECTIVES: Despite changes in pulmonary function, maternal oxygenation is maintained during obstetric regional blocks. But in those situations, the administration of supplementary oxygen to parturients is a common practice. Good fetal oxygenation is the main justification; however, this has not been proven. The objective of this randomized, prospective study was to test the hypothesis of whether maternal hyperoxia is correlated with an increase in fetal gasometric parameters in elective cesarean sections. METHODS: Arterial blood gases of 20 parturients undergoing spinal block with different inspired fractions of oxygen were evaluated and correlated with fetal arterial blood gases. RESULTS: An increase in maternal inspired fraction of oxygen did not show any correlation with an increase of fetal partial oxygen pressure. CONCLUSIONS: Induction of maternal hyperoxia by the administration of supplementary oxygen did not increase fetal partial oxygen pressure. Fetal gasometric parameters did not change even when maternal parameters changed, induced by hyperoxia, during cesarean section under spinal block.

Tako-Tsubo syndrome secondary to residual neuromuscular blockade. Case report.

BACKGROUND AND OBJECTIVES: Tako-Tsubo syndrome is a rare postoperative complication with a 5% mortality rate. The objective of this report was to present residual neuromuscular blockade as a trigger for this syndrome, discuss this disorder, and call attention to the risks of residual neuromuscular blockade. CASE REPORT: A 61-year old female, physical status ASA I, who underwent general anesthesia associated with paravertebral cervical block for arthroscopic repair of a rotator cuff lesion. Physical exam after extubation detected residual neuromuscular blockade. In the post-anesthetic care unit the patient developed somnolence, tachycardia, hypertension, and severe respiratory acidosis. After reintubation the patient evolved for cardiac arrest with electrical activity without a pulse, which was reverted with the administration of adrenaline and external cardiac massage. In the postoperative period the patient presented elevation of the ST segment, increased troponin, and left ventricular medial-apical akinesia with an estimated ejection fraction of 30%. Cardiac catheterization showed absence of significant atheromatous lesions in the coronary vessels, and severe disruption of the systolic function with inferior and antero-septo-apical akinesia and compensatory basal hypercontractility. The patient had complete functional recovery with the treatment instituted. CONCLUSIONS: Residual neuromuscular blockade associated with diaphragmatic paralysis and possible pulmonary atelectasis leading to respiratory failure, hypercapnia, and adrenergic discharge triggered the Tako-Tsubo syndrome with severe clinical repercussion.