Professor, University of Texas Rio Grande Valley School of Medicine
As with spinal anesthesia bacteria h pylori infection generic 100 mg minomycin with mastercard, epidurals are ideally performed with the patient awake virus definition biology cheap 50mg minomycin visa. Chapter 17 Spinal antibiotics to treat lyme disease order generic minomycin, Epidural, and Caudal Anesthesia A variety of different needle approaches exist: midline, paramedian, modified paramedian (Taylor approach), and caudal. A midline approach, in which the angle of approach is only slightly cephalad, is commonly chosen for lumbar and low thoracic approaches. In the midthoracic region, the approach should be more cephalad because of the significant downward angulation of the spinous processes. The needle should be advanced in a controlled fashion with the stylet in place through the supraspinous ligament and into the interspinous ligament, at which point the stylet can be removed and the syringe attached. This method may increase the chance of a false loss-of-resistance, possibly because of defects in the interspinous ligament. Air or saline (or a combination) is commonly used to detect a loss-of-resistance when identifying the epidural space. Each involves intermittent (for air) or constant (for saline) gentle pressure applied to the bulb of the syringe with the dominant thumb while the needle is advanced with the nondominant hand. Usually the ligamentum flavum is identified as a tougher structure with increased resistance, and when the epidural space is subsequently entered, the pressure applied to the syringe plunger allows the solution to flow without resistance into the epidural space. Air is likely less reliable in identifying the epidural space, results in a possible chance of incomplete block, and may cause both pneumocephalus (which can result in headaches) and even venous air embolism in rare cases. Nevertheless, adverse outcomes in obstetric patients do not vary when air versus saline was studied. With the hanging-drop technique, a drop of solution such as saline is placed within the hub of the needle after the needle is placed in the ligamentum flavum. When the needle tip reaches the epidural space, the solution is "sucked in" as a result of subatmospheric pressure inside the epidural space. When a lumbar midline approach is used, the depth from skin to the ligamentum flavum in most (80%) patients is between 3. When the epidural space is identified, the depth should be noted, the syringe removed, and a catheter gently threaded to leave 4 to 6 cm in the space. Less than 4 cm in length in the epidural space may increase the risk of catheter dislodgement and inadequate analgesia. Threading more catheter increases the likelihood of catheter malposition or complications. The needle is inserted into the ligamentum flavum, and a syringe containing saline and an air bubble is attached to the hub. After compression of the air bubble is obtained by applying pressure on the syringe plunger, the needle is carefully advanced until its entry into the epidural space is confirmed by the characteristic loss of resistance to syringe plunger pressure, and the fluid enters the space easily. The needle is then advanced horizontally until the lamina is reached and then redirected medially and cephalad to enter the epidural space. The Taylor approach is a modified paramedian approach via the L5-S1 interspace, which may be useful in trauma patients who cannot tolerate or are not able to maintain a sitting position. The needle is inserted 1 cm medial and 1 cm inferior to the posterior superior iliac spine and is angled medially and cephalad at a 45- to 55-degree angle. Before initiating an epidural local anesthetic infusion, a test dose may be administered. The purpose of this is to exclude intrathecal or intravascular catheter placement.
If hemorrhage is not controlled with standard pharmacologic measures bacteria fighting drug order generic minomycin on line, the obstetric team can consider (1) uterine artery ligation treatment for sinus infection from mold cheap 100mg minomycin visa, (2) B-Lynch sutures infection nursing care plan discount minomycin 100mg without a prescription, (3) an intrauterine balloon, (4) use of arterial embolization by interventional radiology if the patient is stable for transport, or (5) hysterectomy. Placenta Previa Placenta previa results from an abnormal uterine implantation of the placenta in front of the presenting fetus. Risk factors include advanced age, multiparity, assisted reproductive techniques, prior hysterotomy, and prior placenta previa. Historically, the classic presentation of placenta previa is painless vaginal bleeding that typically occurs preterm in the third trimester. A trial of labor is acceptable if the placenta edge is further than 2 cm from the internal os. For placentas that lie between 1 cm and 2 cm from the cervical os, the optimal management remains uncertain and delivery management is currently individualized. Risk factors include advanced age, hypertension, trauma, smoking, cocaine use, chorioamnionitis, premature rupture of membranes, placenta previa, and history of prior abruption. Placental abruption is associated with 10% to 20% of all perinatal deaths, and although maternal death is rare, maternal mortality rate is increased sevenfold. Alternatively, large volumes of blood loss (>2 L) can remain entirely concealed in the uterus. Ultrasound is specific if abruption is noted but has poor sensitivity, and a normal examination does not exclude abruption. The anesthetic plan is based on both the delivery urgency and the abruption severity. If there are no signs of maternal hypovolemia, active bleeding, clotting abnormalities, or fetal distress, epidural analgesia can be used for labor and vaginal delivery. However, severe hemorrhage necessitates emergency cesarean delivery and the use of a general anesthetic similar to that described for placenta previa. It is predictable that neonates born under these circumstances will be acidotic and hypovolemic. Massive Hemorrhage For emergency situations with active hemorrhage, general anesthesia may be required. If a massive hemorrhage occurs, activation of a massive transfusion protocol with aggressive use of fresh frozen plasma, platelets, and fibrinogen 574 Chapter 33 Obstetrics Uterine Rupture Uterine rupture is poorly defined and includes cases ranging from scar dehiscence to those with catastrophic uterine wall rupture. In addition to prior uterine scar, uterine rupture is associated with rapid spontaneous delivery, motor vehicle trauma, trauma from instrumented vaginal delivery, large or malpositioned fetus, and excessive oxytocin stimulation. The presentation is variable with no finding being 100% sensitive but may include fetal bradycardia, persistent abdominal pain, vaginal bleeding, cessation of contractions, loss of station, and breakthrough pain with epidural analgesia. Immediate evaluation, aggressive resuscitation, and general anesthesia for emergent cesarean delivery are normally required for management. Often uterine repair by the obstetrician can occur following cesarean delivery if a minor scar dehiscence is present, but hysterectomy is needed for most cases of uterine wall rupture of an unscarred uterus. Appropriate staffing considerations include obstetric, anesthesia, pediatric, and nursing personnel. Uterine Atony Uterine atony is a common cause of postpartum hemorrhage and can occur immediately after delivery or several hours later. Risk factors for postpartum uterine atony include retained products, long labor, high parity, macrosomia, polyhydramnios, excessive oxytocin augmentation, and chorioamnionitis.
The obstruction produces an increase in left atrial and pulmonary venous pressure antibiotic 50s buy minomycin 50 mg on-line. Distention of the left atrium predisposes to atrial fibrillation antibiotics for uti intravenous order minomycin pills in toronto, which can result in stasis of blood antibiotics for sinus infection didn't work 100 mg minomycin amex, the formation Box 25. Chronic anticoagulation or antiplatelet therapy (or both) of patients with atrial fibrillation can reduce the risk of systemic embolic events. Mitral stenosis is commonly due to the fusion of the mitral valve leaflets during the healing process of acute rheumatic carditis. Symptoms of mitral stenosis do not usually develop until about 20 years after the initial episode of rheumatic fever. A sudden increase in the demand for cardiac output as produced by pregnancy or sepsis, however, may unmask previously asymptomatic mitral stenosis. Patients with mitral stenosis who are being chronically treated with digitalis for the control of heart rate should continue to take this drug throughout the perioperative period. Adequate digitalis effect for heart rate control is generally reflected by a ventricular rate less than 80 beats/min. Because diuretic therapy is common in these patients, the serum potassium concentration should be measured preoperatively. Other common antiarrhythmic drugs such as -adrenergic blockers should also be continued. The discontinuation of anticoagulant or antiplatelet therapy should be discussed with the surgeon and cardiologist. Patients should be switched from warfarin (Coumadin) therapy to heparin therapy prior to surgery depending on the type of case. Also, patients with mitral stenosis can be more susceptible than normal individuals to the ventilatory depressant effects of sedative drugs used for preoperative medication. If patients are given sedative drugs, supplemental oxygen may increase the margin of safety. Most medications that patients are taking, except anticoagulants, antiplatelet drugs, and oral hypoglycemic agents, should be continued throughout the preoperative period. Management of Anesthesia Preinduction of anesthesia placement of an intra-arterial pressure monitoring line can speed the identification and treatment of hemodynamic changes in patients with clinically significant valvular disease. Induction of anesthesia in the presence of mitral stenosis can be achieved with intravenous drugs, with the possible exception of ketamine, which may be avoided because of its propensity to increase the heart rate. Tracheal intubation is facilitated by the administration of a neuromuscular blocking drug. These goals can be achieved with combinations of an opioid and low concentrations of a volatile anesthetic or intravenous anesthetics such as propofol or dexmedetomidine. Rapid increases in the concentration of desflurane may cause tachycardia, bronchospasm, and pulmonary hypertension and should be avoided. Nondepolarizing neuromuscular blocking drugs with minimal circulatory effects are useful in patients with mitral stenosis. The adverse effects of drug-induced tachycardia in response to drug-assisted antagonism of nondepolarizing neuromuscular blocking drugs should be avoided (Box 25. If cases are prolonged and neuromuscular blockade is not required for the conduct of the case, allowing the nondepolarizing neuromuscular blockade to be eliminated through metabolism may reduce the risk of tachycardia with drug-assisted antagonism. Intraoperative intravenous fluid therapy must be carefully titrated because these patients are susceptible to intravascular volume overload and to the development of left ventricular failure and pulmonary edema. Likewise, the head-down position may not be well tolerated because the pulmonary blood volume is already increased. If central pressures are measured, an increase in right atrial pressure could also reflect pulmonary vasoconstriction, suggesting the need to check for causes, which may include nitrous oxide, desflurane, acidosis, hypoxia, increased mitral regurgitation, or light anesthesia.
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