Acute hypoxemia in a parturient with primary ciliary dyskinesia following the administration of intravenous oxytocin: a case report.

PURPOSE: We present the case of a parturient diagnosed with primary ciliary dyskinesia with secondary bronchiectasis who developed significant hypoxemia following administration of intravenous oxytocin during Cesarean delivery under spinal anesthesia. This case suggests that oxytocin can affect pulmonary vascular tone and interfere with the protective effects of hypoxic vasoconstriction. CLINICAL FEATURES: A 35-yr-old primigravida at 37 weeks gestation presented for a scheduled Cesarean delivery due to breech positioning and fetal abnormalities. The patient had a diagnosis of primary ciliary dyskinesia and had undergone a right middle lobectomy seven years earlier for resultant bronchiectasis. Pulmonary function testing in the month prior to delivery showed a 4% decline in her baseline FEV1 to 1.06 L (32% of predicted value) but she was functionally well. The patient initially had an uneventful spinal anesthetic and maintained an oxygen saturation of 97% on room air in the supine position until delivery of her baby. An intravenous infusion of oxytocin for uterine contraction was started following removal of the placenta. The patient then became acutely hypoxemic with a drop in room air saturation to 84% but with no other accompanying hemodynamic instability. Maternal oxygen saturation did not improve with the addition of supplemental oxygen, and the patient had a significant arterial-alveolar oxygen gradient suggesting an intrapulmonary shunt. No supporting clinical, radiologic, or laboratory evidence of a thrombotic, air, or amniotic fluid embolism or mucous plug was detected. The patient remained hypoxemic during the postoperative period with gradual improvement back to baseline saturation in approximately 48 hr. CONCLUSION: The vasodilatory effects of intravenous oxytocin on the pulmonary vasculature may worsen shunting and interfere with hypoxic pulmonary vasoconstriction, producing clinically significant hypoxemia in patients with comorbid lung disease. Oxytocin should be used with caution in patients with compromised lung function.

Life-threatening adverse events following therapeutic opioid administration in adults: is pharmacogenetic analysis useful?

BACKGROUND: Systemic approaches are needed to understand how variations in the genes associated with opioid pharmacokinetics and response can be used to predict patient outcome. The application of pharmacogenetic analysis to two cases of life-threatening opioid-induced respiratory depression is presented. The usefulness of genotyping in the context of these cases is discussed. METHODS: A panel of 20 functional candidate polymorphisms in genes involved in the opioid biotransformation pathway (CYP2D6, UGT2B7, ABCB1, OPRM1, COMT) were genotyped in these two patients using commercially available genotyping assays. RESULTS: In case 1, the patient experienced adverse outcomes when administered codeine and morphine, but not hydromorphone. Genetic test results suggested that this differential response may be due to an inherent propensity to generate active metabolites from both codeine and morphine. These active metabolites are not generated with hydromorphone. In case 2, the patient experienced severe respiratory depression during postoperative recovery following standard doses of morphine. The patient was found to carry genetic variations that result in decreased morphine efflux transporter activity at the blood-brain barrier and increased sensitivity to opioids. CONCLUSIONS: Knowledge of the relative contribution of pharmacogenetic biomarkers and their influence on opioid response are continually evolving. Pharmacogenetic analysis, together with clinical history, has the potential to provide mechanistic insight into severe respiratory depressive events in patients who receive opioids at therapeutic doses.

Regional anesthesia for the management of limb injuries in space.

Traumatic injuries continue to present a threat to the success of current and future spaceflight missions. The magnitude of this threat will grow as the frequency of extravehicular activities is increased and missions venture beyond low Earth orbit and further away from terrestrial medical support. The capability to render definitive treatment to crewmembers who suffer a serious traumatic injury while in space is relatively limited at present. While some research has focused on the development of specific surgical techniques for the microgravity environment, little attention has been given to how one might practically provide anesthetic care for injured crewmembers expected to undergo these procedures. While many logistical and practical obstacles exist to the provision of general anesthesia in microgravity, regional anesthesia could be used to overcome many of these problems. A regional anesthetic capability for spaceflight missions could be developed with minimal modifications to existing terrestrial techniques and would provide the ability to manage a wide range of potential injuries while in orbit. The capability to provide reliable regional anesthesia could be further augmented and improved using a range of imaging technologies currently in development; it is expected that these devices would have a range of terrestrial applications, including the ability to provide immediate, safe, and reliable anesthetic care to patients in remote locations, or under austere conditions such as the combat environment.