A 26-year old primigravida with severe rheumatic heart disease (mitral stenosis with mitral regurgitation) is in early labour. The obstetrician wants to try a normal labour. Which of the following is the ideal intervention for labour analgesia?
Ans. is Neuraxial analgesia Pain and anxiety during labour and delivery provoke catecholamine surge resulting in tachycardia, hypertension increased cardiac output and increased systemic vascular resistance.This may prove to be catastrophic for patients with heart disease who may develop ischemia or heart failure.* This can be prevented by providing adequate labour analgesia.Earlier spinal neuraxial blockade was used for this purpose.It was believed that sympathetic neuraxial blockade will provide adequate analgesia. However, sympathetic blockade caused by standard neuraxial techniques can produce dramatic cardiovascular changes with decrease in cardiac output secondary to a reduction in preload following sympathetic blockade.Standard spinal blockade is considered a cardiovascular risk due to the sympathetic blockade that decreases cardiac preload by causing arteriolar dilatation. Arteriolar dilatation will reduce systemic vascular resistance and may cause reflex tachycardia.Standard spinal block may produce following changes: -Low systemic vascular resistance can reverse the pressure gradient across a left to right intracardiac shunt, leading to catastrophic decrease in pulmonary blood flow.These changes are usually more severe with a single shot spinal anaesthesia compared with central neuraxial blockade. However, in the last few years, neuraxial blockade has benefitted from important technical and pharmacological improvements that allow it to be tailored to the patients' needs and obstetric course.Safe neuraxial techniques avoid standard techniques with fixed doses and instead should tailor the anaesthetic to the patient.Single shot spinal anaesthesia is not recommended for the cardiac pregnant patient, in contrast a well-controlled epidural or spinal anaesthesia is beneficial even for the most severe cardiac disease.If a rapid decrease in preload and afterload are likely to compromise cardiac status then local anaesthetic is eliminated from the intrathecal portion of the spinal epidural (CSE) and only intrathecal opioid is administered.In these patients the epidural should be dosed slowly with local anaesthetic to maintain stable hemodynamics and adequate uteroplacental blood flow.The technique carries the risk of potential delay in the discovery of poorly placed epidural catheter after a combined spinal epidural (CSE): however, epidural catheters placed during a CSE are less likely to fail.If neuraxial analgesia is not an option for a high-risk cardiac patient, then the advisability of vaginal delivery may need to be considered.Although patient controlled analgesia (PCA) via intravascular opioid infusion with remifantil or fentanyl is performed in many patients, this may not be good alternative for the cardiac patient.Pain control is typically suboptimal leading to increased catecholamine release. Furthermore to achieve, even moderately effective analgesia, the dose of opioid required could suppress ventilation. The resultant carbon di-oxide retention can cause respiratory acidosis, further catecholamine release and increase pulmonary hypertension leading to arrhythmias, ischemia, or heart, failure.Mitral stenosisThe main goal of anaesthetic technique is to avoid "tachycardia" as the time required for left ventricular diastolic filling is prolonged.Segmental epidural anaesthesia is recommended early during labour, avoiding significant decrease in systemic vascular resistance with reflex tachycardia.Cesarean section is also managed with segmental epidural anaesthesia.Phenylephrine is the vasopressor of choice.Patients with prominent symptoms are at significant risk in peripartum period and should receive peripheral and pulmonary artery catheter monitoring continued for a minimum of 24 hour after delivery since tolerance to postpartum fluid shifts may be poor.Mitral regurgitationMitral insufficiency as well as mitral value prolapsed are well tolerated by the pregnant patient since a decrease in SVR will reduce the regurgitant flow.Atrial arrhythmias and risk of embolism from atrial thrombi are important complications.Pain will automatically increase systemic vascular resistance and adequate labour analgesia should minimize peripheral vasoconstriction and thus avoid an increase in left ventricular after load associated with labour pain.Additional sympathetic blockade further decreases systemic vascular resistance.Neuraxial techniques are indicated for labour, vaginal delivery and cesarean section.
Parenteral opioids
Neuraxial analgesia
Inhalational analgesia
Spinal anaesthesia
Pathology of Conception