It is estimated that postpartum hemorrhage affects 10% of deliveries. Oxytocic drugs are used to increase uterine tone and for the prevention of postpartum hemorrhage and its treatment. They are divided into three groups: oxytocin, prostaglandins, and methylergonovine. Oxytocin can be used in prevention and treatment, and it is considered the first-line treatment for postpartum hemorrhage. It can be given intravenously and intramuscularly. The most common side effect is hypotension. Second-line drugs include Carboprost (IM, intrauterine), which is contraindicated in asthma due to its ability to induce bronchospasm; Misoprostol (per rectum, sublingually) is safe in asthma; and methylergonovine (IM), which is contraindicated in hypertension.
Diabetes mellitus (DM) is a common chronic disorder associated with cardiovascular disease and microvascular complications, often necessitating surgical intervention. These patients are at an increased risk of perioperative infection and postoperative morbidity and mortality. The complex interplay of stress from surgery, anesthesia, and fasting, along with additional postoperative factors such as infection, altered nutritional intake, hyperalimentation, and emesis, can lead to labile blood glucose levels. There is a clear association between perioperative hyperglycemia and adverse clinical outcomes, although the exact mechanism(s) underlying this remains unclear. Perioperative DM management focuses on glycemic control. Substantial evidence indicates that the correction of hyperglycemia with insulin administration reduces complication rates and decreases mortality in cardiac and general surgery patients.
The α2-receptors bind with norepinephrine (NE) and epinephrine (E) and inhibit the release of further NE and subsequent neural firing. The two potent α2-agonists used in practice are dexmedetomidine and clonidine. Dexmedetomidine is a specific α2-adrenoceptor agonist with sedative, anxiolytic, analgesic, and sympatholytic properties. It has minimal effect on respiratory drive, which is a key advantage. It has a quick onset and short duration of action. Currently, it has only been licensed for use in intravenous infusions in the intensive care unit (ICU) for 24 hours. If used more than 24 hours, rebound hypertension is common. Following a rapid intravenous bolus (especially a high dose), it shows biphasic blood pressure response of the initial short phase of hypertension (HTN) and subsequent hypotension. Usually, the bradycardia produced by dexmedetomidine is clinically insignificant but may be significant in elderly patients, patients with heart blocks or severe cardiac diseases, and patients using heart rate–slowing medications. It is useful as a premedication, adjunct in general anesthesia (GA) and regional anesthesia (RA), ICU and procedural sedation, monitored anesthesia care (MAC) sedation, treatment and prevention of emergence delirium and postoperative shivering, and chronic pain. Clonidine has been traditionally used as an antihypertensive agent but has been found useful as an adjunct in GA and RA because of its similar properties of sedation, anxiolysis, analgesia, and sympatholysis. Other uses include treatment of opioid-induced hyperalgesia; ethyl alcohol, opioid, and nicotine withdrawal, treatment, and prevention of emergence delirium; and postanesthetic shivering. Rebound HTN and biphasic responses are seen with clonidine as well.
Pregnancy affects almost every organ system in a parturient’s body. Various anatomical and physiological changes in pregnancy that have significant implications for an anesthesiologist caring for a pregnant patient. Pregnant patients are more likely to present with a difficult airway and a high risk of aspiration during anesthesia. The incidence of difficult mask ventilation and difficult intubation is higher than in nonpregnant patients. All patients should be considered as having a full stomach from 16 weeks of pregnancy to 48 hours postpartum. There are significant cardiovascular changes, such as supine hypotension syndrome, which mandates left uterine displacement when a parturient is supine. There is an increase in plasma volume more than red cell volume, resulting in physiological anemia of pregnancy and an increase in both cardiac output and heart rate with a decrease in systolic and diastolic blood pressures—all changes designed for coping with blood loss during delivery. There is a reduction in functional residual capacity (FRC) due to the gravid uterus pushing the diaphragm up. The increased oxygen consumption, along with reduced FRC, can lead to faster desaturation, and adequate preoxygenation is vital. Pregnancy is also a hypercoagulable state meant for minimizing blood loss during delivery, and the incidence of deep vein thrombosis and pulmonary embolism is higher than for nonpregnant patients, so these patients will routinely receive thromboprophylaxis. The minimum alveolar concentration 50 is reduced by about 30%–40% in pregnant patients, and the dose of local anesthetic for neuraxial blocks should be reduced by 25%–40%.
Cesarean delivery is the most common surgical procedure performed worldwide. There are various indications related to maternal, fetal, uterus, or placental pathology. Preoperative evaluation includes review of past medical and obstetric history, including physical examination of airway, heart, and lungs. A blood type and crossmatch, intravenous access, aspiration prophylaxis, postoperative nausea and vomiting (PONV) management, and prophylactic antibiotics are integrals part of a preoperative plan. Neuraxial anesthesia is the preferred method of anesthesia for caesarian section unless there is an absolute contraindication. Advantages of neuraxial anesthesia include decreasing maternal mortality, limited neonatal drug transfer, ability of the parents to be awake and take part in the delivery during the birth of their child, and avoiding airway manipulation in patients who have both a potentially difficult airway and an aspiration risk. Different neuraxial techniques used for caesarian section include epidural, single-shot spinal, combined spinal-epidural, and spinal catheter. In case of general anesthesia, all equipment should be readily available with standard American Society of Anesthesiologist monitoring, including pulse oximetry, electrocardiography (ECG), capnography, and noninvasive blood pressure (NIBP). Rapid sequence induction and intubation with cricoid pressure are preferred after preoxygenation. All airway instruments should be available for a potential difficult airway, including an awake intubation plan if indicated. Anesthetic complications include intraoperative awareness and recall, dyspnea following neuraxial anesthesia, hypotension, failure of neuraxial blockade, high neuraxial blockade, difficult airway/trauma to the airway, and nausea and vomiting. Some of the important aspects of postoperative management include postoperative pain, pruritus, hypothermia, hemorrhage, and thromboembolic events.
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