Physiological and anatomical changes of pregnancy: Implications for anaesthesia

Abstract

During pregnancy, the body goes through various anatomical and physiological changes to provide suitable environment for foetal development, to cater to the increased metabolic demands and to prepare for the childbirth. These changes have notable anaesthetic implications in determining the optimal anaesthetic technique, while also keeping in mind the gestational age, type of procedure and any coexisting medical condition. It is important to note that these changes revert to baseline (pre-pregnancy) levels at different time intervals during the postpartum period which is important while managing postpartum patients. None of the anaesthetic agents are known teratogens; however, there is concern regarding the effects of some agents on the developing brain.

Anaesthetic management of a parturient with spondylothoracic dysostosis

“…Intermittent monitoring of oxygen saturation is necessary and supplemental oxygen therapy may be required as oxygen demands increase after the first trimester 13. Mild-moderate relative hypercapnia results from limited ability of parturient to increase minute ventilation, as seen in our patient 7 8…”

“…Practitioners taking care of patients with STD perioperatively need to address difficulties posed by vertebral anatomy, airway and severe restrictive lung disease. In the context of pregnancy, these challenges are amplified secondary to perinatal physiological effects 7…”

Anaesthesia for emergency caesarean section in a patient with Gitelman syndrome

“…Regional anaesthetic techniques may be preferable over general anaesthesia to avoid polypharmacy and risk of failed intubation and aspiration, and it also provides better post-operative analgesia. [ 12 ] Epidural or combined spinal epidural anaesthesia could be used. Uneventful spinal anaesthesia for caesarean delivery in pregnant women with Gitelman syndrome have been reported.…”

Role of the Registered Nurse in the Care of the Pregnant Woman Receiving Analgesia and Anesthesia by Catheter Techniques

“…The pregnant woman differs physiologically and anatomically from the non-pregnant woman, and these differences can increase the risk for complications with use of regional analgesia and anesthesia. As a result of pregnancy, edema can develop in the oral and nasal pharynx, larynx, and trachea, which presents a challenge to maintaining the airway and to successful intubation during resuscitation should an emergency occur (American Heart Association, 2015; Bhatia & Chhabra, 2018;Kamcar & Gaiser, 2019). Oxygen consumption increases as pregnancy progresses, and this change coupled with the fact that functional residual lung capacity is often decreased by 10% to 25% (American Heart Association, 2015) means that the pregnant woman can decompensate much more rapidly during physiologic compromise or during resuscitation than a woman who is not pregnant.…”

“…Furthermore, pregnancy results in down-regulation of beta-adrenergic receptors that decreases responsiveness to chronotropic agents and vasopressors (Kamcar & Gaiser, 2019), which can threaten successful response to standard treatment for hypotension. Pregnant women are at greater risk for unintentional intravascular cannulation than women who are not pregnant (Bhatia & Chhabra, 2018;Wong, 2019). Epidural venous engorgement, which occurs with uterine enlargement and compression of the vena cava, can increase the potential for catheter migration (Nathan & Wong, 2019).…”