The absence of teratogenic effects of some analgesics used in anaesthesia

Opioid effect on the autonomic nervous system in a fetal sheep model

PURPOSE

Opioid use during labour can interfere with cardiotocography patterns. Heart rate variability indirectly reflects a fluctuation in the autonomic nervous system and can be monitored through time and spectral analyses. This experimental study aimed to evaluate the impact of nalbuphine administration on the gasometric, cardiovascular, and autonomic nervous system responses in fetal sheep.

METHODS

This was an experimental study on chronically instrumented sheep fetuses (surgery at 128 ± 2 days of gestational age, term = 145 days). The model was based on a maternal intravenous bolus injection of nalbuphine, a semisynthetic opioid used as an analgesic during delivery. Fetal gasometric parameters (pH, pO₂, pCO₂, and lactates), hemodynamic parameters (fetal heart rate and mean arterial pressure), and autonomic nervous system tone (short-term and long-term variation, low-frequency domain, high-frequency domain, and fetal stress index) were recorded. Data obtained at 30-60 min after nalbuphine injection were compared to those recorded at baseline.

RESULTS

Eleven experiments were performed. Fetal heart rate, mean arterial pressure, and activities at low and high frequencies were stable after injection. Short-term variation decreased at T30 min (P = 0.02), and long-term variation decreased at T60 min (P = 0.02). Fetal stress index gradually increased and reached significance at T60 min (P = 0.02). Fetal gasometric parameters and lactate levels remained stable.

CONCLUSION

Maternal nalbuphine use during labour may lead to fetal heart changes that are caused by the effect of opioid on the autonomic nervous system; these fluctuations do not reflect acidosis.

Safety of endoscopic retrograde cholangiopancreatography during pregnancy for disease diagnosis and treatment

At present, endoscopic retrograde cholangiopancreatography (ERCP) is one of the most commonly used methods for diagnosis and treatment of biliopancreatic diseases. However, over the years, ERCP has been avoided in pregnancy given the concerns regarding the adverse effects, such as the safety of sedative drugs, the impact of radiation on the developing fetus, and the complications of ERCP. However, years of research has shown that it is safe and effective to perform ERCP during pregnancy, and the postponement or rejection of ERCP in pregnant women may lead to a higher risk for mother and fetus, especially when the indication is unequivocal (e.g., cholangitis, biliary pancreatitis, and symptomatic choledocholithiasis). This article gives an overview of the safety of ERCP during pregnancy for disease diagnosis and treatment.

Risks versus benefits of gastrointestinal endoscopy during pregnancy

Although gastrointestinal endoscopy is generally safe, its safety must be separately analyzed during pregnancy with regard to fetal safety. Fetal risks from endoscopic medications are minimized by avoiding FDA category D drugs, minimizing endoscopic medications, and anesthesiologist attendance at endoscopy. Esophagogastroduodenoscopy seems to be relatively safe for the fetus and may be performed when strongly indicated during pregnancy. Despite limited clinical data, endoscopic banding of esophageal varices and endoscopic hemostasis of nonvariceal upper gastrointestinal bleeding seems justifiable during pregnancy. Flexible sigmoidoscopy during pregnancy also appears to be relatively safe for the fetus and may be performed when strongly indicated. Colonoscopy may be considered in pregnant patients during the second trimester if there is a strong indication. Data on colonoscopy during the other trimesters are limited. Therapeutic endoscopic retrograde cholangiopancreatography seems to be relatively safe during pregnancy and should be performed for strong indications (for example, complicated choledocholithiasis). Endoscopic safety precautions during pregnancy include the performance of endoscopy in hospital by an expert endoscopist and only when strongly indicated, deferral of endoscopy to the second trimester whenever possible, and obstetric consultation.

Gastrointestinal medications in pregnancy

Management of the pregnant patient presents unique challenges to the treating physician. Current Food and Drug Administration classifications do not necessarily reflect clinical experience or recent literature. Ideally, one should use the lowest-risk drug possible, with attention to the appropriate level of efficacy for the patient's condition, the stage of pregnancy and dose adjustment. Every treatment decision should be fully discussed with the patient and a multidisciplinary team that should include the obstetrician and, if appropriate, the paediatrician. This review will cover the medications commonly used to treat gastrointestinal disease. The majority of medications can be categorised as 'low risk' or 'should be avoided'. The following medications should never be used during pregnancy due to the clear risk of teratogenicity or adverse events: bismuth, castor oil, sodium bicarbonate, methotrexate, ribavirin, doxycycline, tetracycline, and thalidomide.

American gastroenterological association institute technical review on the use of gastrointestinal medications in pregnancy

This literature review and the recommendations therein were prepared for the American Gastroenterological Association Institute Clinical Practice and Economics Committee. The paper was approved by the Committee on February 22, 2006 and by the AGA Institute Governing Board on April 20, 2006.

Cardiopulmonary bypass and mitral valve replacement during pregnancy

Gravid patient cardiopulmonary bypass remains a high-risk procedure with regard to fetal preservation. Maternal mortality is similar to that of the nonpregnant female at 1.5-5%. However, fetal mortality remains high at 16-33%, with an average of 19% over the past 25 years, with no correlation to gestational age. Teratogenesis is a major consideration in the first trimester. Variations in the timing of surgical intervention, gestational age, maternal health status, type of procedure, pre- or postorganogenesis, perfusion protocol, and pharmaceutical therapy are all factors that can influence fetomaternal outcome. In this report, we present a literature review along with our experience of a 26-year-old female who developed complications with her pregnancy at approximately 17 weeks gestation, with adverse neurological sequelae. The patient was 152 cm in height and weighed 48 kg, with a calculated body surface area of 1.40 M2. She had no prior history of cardiac disease and, upon admission to our institution, presented with a declining health status in pulmonary edema and was treated medically, with an ultimate requirement for mitral valve replacement. The total cardiopulmonary bypass time was 99 min with an aortic crossclamp time of 83 min. The literature, as expected, is limited to case reports and reviews since a controlled clinical trial during pregnancy is nonexistent, using extracorporeal circulation. This greatly challenges the medical staff in managing such difficult cases, with an incidence of heart disease during pregnancy of 1.2-3.7%.

Sedation and analgesia for gastrointestinal endoscopy during pregnancy

Endoscopy during pregnancy raises the unique issue of fetal safety. Endoscopic medications comprise a significant component of fetal risks from endoscopy. Before endoscopy, the gastroenterologist or anesthesiologist should evaluate the potential fetal risks of sedation and analgesia, identify any contraindications to endoscopy, stabilize the maternal medical status as necessary, and correct maternal hypoxia or hypotension. The mother should be informed about the potential teratogenic risks of endoscopic medications during pregnancy. Patients who receive sedation and analgesia should be monitored during endoscopy by continuous electrocardiography, continuous pulse oximetry, and intermittent sphygmomanometry, as well as by the pulse and respiratory rate. General principles of sedation and analgesia during pregnancy include use of the minimal effective dose, avoidance of unnecessary medications, and preferable use of Food and Drug Administration category B medications.

The fetal safety and clinical efficacy of gastrointestinal endoscopy during pregnancy

More than 12,000 pregnant patients in the United States per annum have conditions that are normally evaluated by EGD. More than 6000 pregnant patients in the United States per annum have conditions that are normally evaluated by sigmoidoscopy or colonoscopy. About one thousand more have symptomatic choledocholithiasis during pregnancy, which is a strong indication for endoscopic sphincterotomy in nonpregnant patients. Endoscopy during pregnancy raises the unique issue of fetal safety. Endoscopic medications comprise a significant component of fetal endoscopic risks. Safety of EGD during pregnancy has been examined in a case-controlled study of 83 patients, a mailed survey of 73 patients, and 28 case reports. Safety of sigmoidoscopy during pregnancy has been examined in a case-controlled study of 46 patients, a mailed survey of 13 patients, and 10 case reports. Safety of therapeutic ERCP during pregnancy has been analyzed in studies of 23, 10, 6, and 5 patients, and in 32 case reports. These studies suggested that EGD, sigmoidoscopy, and ERCP should be performed when strongly indicated: EGD for significant upper gastrointestinal bleeding, sigmoidoscopy for nonhemorrhoidal rectal bleeding, and ERCP for symptomatic choledocholithiasis when sphincterotomy is contemplated. PEG and colonoscopy are currently considered experimental during pregnancy because of insufficient data on fetal safety. Several cases of PEG and colonoscopy were successfully performed during pregnancy. Performance of endoscopy during pregnancy should increase with further technical refinements, and greater awareness of procedure safety.

Antiarrhythmic drugs in pregnancy

During pregnancy a number of rhythm disturbances can occur in both the mother and fetus; these may range from benign ectopy to life-threatening arrhythmias. With a clear understanding of the maternal hemodynamic changes associated with pregnancy, and the appropriate antiarrhythmic therapies available, almost all such cases can be treated successfully. Although no drug is completely safe, most are well tolerated and can be given with relatively low risk. Drug therapy should be avoided during the first trimester of pregnancy if possible and drugs with the longest record of safety should be used as first-line therapy. Conservative therapies should be used when appropriate. Several drug options exist for most maternal and fetal arrhythmias.