Subject(s)
Brain/diagnostic imaging , Cerebrovascular Circulation/physiology , Post-Dural Puncture Headache/diagnostic imaging , Puerperal Disorders/diagnostic imaging , Ultrasonography, Doppler, Transcranial/methods , Blood Patch, Epidural , Brain/blood supply , Brain/physiopathology , Female , Humans , Pilot Projects , Post-Dural Puncture Headache/physiopathology , Post-Dural Puncture Headache/therapy , Pregnancy , Prospective Studies , Puerperal Disorders/physiopathology , Puerperal Disorders/therapy , Treatment OutcomeABSTRACT
Venous thromboembolic disease accounts for 9% of all maternal deaths in the United States. In patients at risk for thrombosis, common practice is to start prophylactic doses of low-molecular-weight heparin and transition to unfractionated heparin during the third trimester, with the perception that administration of neuraxial anesthesia will be safer while on unfractionated heparin, as spinal/epidural hematomas have been associated with recent use of low-molecular-weight heparin. In patients receiving prophylactic doses of unfractionated heparin, neuraxial anesthesia may be placed, provided the dose used is 5,000 units twice a day. The American Society of Regional Anesthesia and Pain Medicine guidelines recognize that the safety of neuraxial anesthesia in patients receiving more than 10,000 units per day or more than 2 doses per day is unknown, limiting the theoretical benefit of unfractionated heparin at doses higher than 5,000 units twice a day.
Subject(s)
Anticoagulants/therapeutic use , Heparin, Low-Molecular-Weight/therapeutic use , Heparin/therapeutic use , Pregnancy Complications, Hematologic/prevention & control , Venous Thromboembolism/prevention & control , Anesthesia, Obstetrical/adverse effects , Drug Substitution , Female , Hematoma, Epidural, Spinal/etiology , Hematoma, Epidural, Spinal/prevention & control , Humans , Pregnancy , Pregnancy Trimester, ThirdSubject(s)
Anesthesia, Epidural , Anesthesia, Obstetrical , Cesarean Section , Heart Defects, Congenital , Heart Valve Prosthesis , Labor, Obstetric , Pregnancy Complications, Cardiovascular , Adult , Female , Heart Atria/surgery , Heart Defects, Congenital/surgery , Humans , Pregnancy , Pulmonary Artery/surgeryABSTRACT
BACKGROUND: Studies in experimental animals show that endogenous Arg-vasopressin (AVP) and the renin-angiotensin system support blood pressure when the sympathetic system is impaired pharmacologically or after epidural anesthesia. However, extrapolation to humans is uncertain. Therefore, we administered an AVP type V1 receptor antagonist and an angiotensin-converting enzyme inhibitor to volunteers and measured the effect on blood pressure after epidural anesthesia. METHODS: Healthy volunteers in whom epidural catheters were placed were randomly assigned to receive 1.25 mg intravenous enalapril or saline placebo followed by 0.5 mg AVP type V1 antagonist beta-mercapto-beta, beta-cyclopentamethylene-propionyl-o-Met-Tyr-Arg-vasopressin (AVPA) or saline placebo. Finally, 2% lidocaine was injected to obtain a T2 level. Controls received intramuscular lidocaine. RESULTS: Blood pressure did not significantly change after T-2 epidural anesthesia in subjects treated with saline placebo, AVPA or enalapril alone (n = 10, for each treatment). In contrast, combined treatment with enalapril and AVPA resulted in a 36 +/- 11% decrease in blood pressure after epidural dosing (n = 6). Controls given intramuscular lidocaine, in place of the epidural did not develop hypotension after AVPA and enalapril treatment (n = 10). CONCLUSIONS: Endogenous AVP and the renin-angiotensin system play important roles in maintaining blood pressure after epidural anesthesia in healthy subjects.
