Comparison of Postoperative Pulmonary Outcomes in Patients Undergoing Cesarean Section under General and Spinal Anesthesia: A Single-Center Audit.

Introduction: Regional anesthesia (RA), i.e., spinal or epidural anesthesia when performed for lower segment cesarean section (LSCS) provides excellent surgical conditions, avoiding manipulation of the maternal airway, maternal satisfaction, and good postoperative analgesia. However, in situations like fetal distress (fetal heart rate abnormalities), obstetric indications (abruption of placenta, antenatal placental bleeding, cord prolapse), maternal refusal for RA, contraindications to neuraxial anesthesia (anticoagulation, coagulopathy), and at times failed RA general anesthesia (GA) is administered. Several studies have demonstrated greater mortality and morbidity when LSCS is done under GA when compared to neuraxial block.
Methods: After necessary approval, we retrospectively reviewed data over a period of 1 year (January 1, 2020-December 31, 2020) of LSCS under GA versus RA. The aim was to compare immediate postoperative complications, postoperative pulmonary complications up to 4 weeks from the time of elective and emergency LSCS under either RA or GA.
Results: Of the 753 patients who underwent LSCS in one calendar year, there were 272 (36.12%) elective and 481 (63.87%) emergency LSCS. The number of elective LSCS under neuraxial block was 219 (29.09%) and under GA were 53 (7.03%). Emergency LSCS done under neuraxial block were 268 (35.59%) and under GA were 213 (28.28%). There were no adverse pulmonary complications at the end of 4 weeks in either group.
Conclusion: RA provides maternal satisfaction and excellent perioperative analgesia in LSCS. Safe GA can be achieved with proper airway planning, if case is attended by at least two anesthesiologist with adequate preoperative fasting, and postoperative monitoring. Copyright:

INTRODUCTION

Central neuraxial block (subarachnoid block or lumbar epidural) also called as regional anesthesia (RA) is the gold standard technique of anesthesia for elective and at times even urgent or emergency lower segment cesarean section (LSCS).[1] The advantages are excellent surgical conditions, avoiding manipulation of the maternal airway, maternal satisfaction, and good postoperative analgesia. However, there are situations where general anesthesia (GA) for LSCS is inevitable. These conditions are fetal distress (fetal heart rate abnormalities based on cardiotocography), obstetric indications (abruption of placenta, antenatal placental bleeding, cord prolapse), maternal refusal for central neuraxial block, contraindications to neuraxial anesthesia (anticoagulation, coagulopathy), and at times failed neuraxial block.[2]

The Society for Obstetric Anesthesia and Perinatology recommends that the overall rate of GA for LSCS should be lower than 5%.[3] Similarly, the Royal College of Anaesthetists’ recommends a rate lower than 1% for elective LSCS and <5% for emergency LSCS.[4] Several studies have demonstrated greater mortality and morbidity when LSCS is done under GA when compared to neuraxial block. The common problems encountered are increased blood loss, increased chances of thromboembolism, postoperative pulmonary complications (airway mishaps, aspiration), and surgical site infections. Other issues of concern are less maternal satisfaction, poor quality of postoperative analgesia, postoperative nausea/vomiting, prolonged hospitalization, intraoperative awareness, and adverse neonatal outcomes such as admission to neonatal intensive care unit, assisted ventilation, lower Apgar scores.[56]

In this study, the primary outcome was to compare postoperative pulmonary complications in patients undergoing elective or emergency LSCS under RA or GA. The secondary outcomes were to estimate percentage of RA and GA that was offered for elective and emergency LSCS.

METHODS

This retrospective audit was conducted at Ibra Hospital, North Sharqiya Governorate, Sultanate of Oman. After obtaining an institutional approval, we retrospectively reviewed data over a period of 1 year (January 1, 2020–December 31, 2020) of LSCS under GA versus RA. Being a retrospective study, informed consent was not applicable. The data were collected from Al Shifa patient information portal which is an electronic medical record system available for all hospitals under Ministry of Health, Oman. By searching using keywords: cesarean section, elective, emergency, anesthesia for the time frame from January 1, 2021, to December 31, 2021 data was retrieved. The aim was to compare postoperative pulmonary complications up to 4 weeks from the time of elective and emergency LSCS under either RA or GA. Other parameters that were retrieved and compared were duration of postoperatively, percentage of patients who were offered RA or GA for elective or emergency LSCS, timing of hospital discharge. Demographic data like age, gravida, parity were also retrieved and compared. Appropriate statistical test was used to compare various variables. For continuous data like age, gravida, parity, mean ± standard deviation or median (interquartile range) was used as applicable. The categorical data were compared using Fisher exact test. The statistical tests were performed using the online statistical tool GraphPad (https://www.graphpad.com/). A P < 0.05 was considered as statistically significant.

RESULTS

We retrieved data of 753 patients who underwent LSCS from January 1, 2020, to December 31, 2020. The data were entered in a Microsoft Excel sheet (Microsoft Corporation, Redmond, Washington, United States). The relevant demographic data are depicted in Table 1. There were 272 (36.12%) elective and 481 (63.87%) emergency LSCS. Number of elective LSCS under neuraxial block were 219 (29.09%) and under GA were 53 (7.03%). Emergency LSCS done under neuraxial block were 268 (35.59%) and under GA were 213 (28.28%) [Figure 1 and Table 2]. As depicted in Table 2, there were no adverse pulmonary complications at the end of 4 weeks both in RA and GA group irrespective of whether it was elective or emergency.

Table 1

Comparison of demographic data and pulmonary outcomes

Variables	Elective		P	Emergency		P
	RA (n=219)	GA (n=53)		RA (n=268)	GA (n=213)
Age (years)	35 (30-38)	35 (31.5-39)	0.1954	32.5 (27-37)	30 (26-35)	0.0012
Gravida	4 (3-6)	5 (3-6)	0.1015	3 (2-6)	3 (2-5)	0.2432
Parity	3 (2-4)	3 (2-4)	0.7652	2 (1-4)	3 (1-4)	0.1841
Immediate postoperative pulmonary events	0	0	-	0	0	-
Day of discharge	2	2 (2-2.5)	0.0096	2 (2-3)	2 (2-3)	0.1334
Pulmonary events in 4 weeks	0	0	-	0	0	-

RA=Regional anesthesia, GA=General anesthesia

Figure 1

Comparison of cesarean sections (elective and emergency) under general anesthesia and Regional anesthesia

Table 2

Details of various categories of lower segment cesarean section

Nature of surgery	Type of anaesthesia	Number of patients (%)	Total
Elective (272)	RA	219 (80.5)	272
	GA	53 (19.5)
Emergency (481)	RA	268 (55,7)	481
	GA	213 (44.2)

RA=Regional anesthesia, GA=General anesthesia

DISCUSSION

From this single institute retrospective cohort study, we inferred that there were no postoperative pulmonary complications in patients undergoing elective or emergency LSCS under RA or GA. In our center, LSCS under GA was 35.32% (elective: 7.03% and emergency: 28.28%) which was several times higher than that suggested by various societies. This was slightly lesser than that mentioned by Nafisi et al. which was an observational study from the Middle East involving 465 LSCS under GA. The authors also mentioned that type of anesthesia practiced and offered to the parturient for LSCS also depends on the ethnicity, race, and socioeconomic characteristics and that GA for LSCS is safe with minimal risk.[7]

In a retrospective analysis of LSCS over 10 years, Palanisamy et al. reported that the percentage of cases performed under GA was 0.5%–1%. For GA, maternal factors responsible were from 11.1% to 42.9%, failures of RA were <4% of the GA cases with only one case of difficult intubation and no anesthesia-related mortality. The rate of GA was acceptable during this decade.[8] However, in a survey conducted by Stourac et al. in Czech Republic, authors found that although there was an increase in neuraxial anesthesia for LSCS, the use of GA was still higher when compared to western countries (emergency procedure-67%, refusal of neuraxial blockade by parturient-30%, failure of neuraxial anesthesia-6%, and preoperative use of low-molecular-weight heparin-3%.[9] At our center, the use of GA was much lesser compared to the findings of Stourac et al.

In a retrospective study involving patients undergoing LSCS from the year 2003–2014, Guglielminotti et al. revealed that avoidable general anesthetics were associated with significantly increased risk of anesthesia complications (adjusted odds ratio, 1.6; 95% confidence interval [CI], 1.4–1.9), severe complications (adjusted odds ratio, 2.9; 95% CI, 1.6–5.2), surgical site infection (adjusted odds ratio, 1.7; 95% CI, 1.5–2.1), and venous thromboembolism (adjusted odds ratio, 1.9; 95% CI, 1.3–3.0).[10] As per information available from electronic data system, we did not experience any anesthesia-related or perioperative pulmonary complications. Ikeda et al. highlighted the fact that with the formation of an obstetric anesthesia team in their hospital, there was a significant decrease in LSCS under GA as there were stringent evidence-based protocols.[11]

The potential difficulties of GA for LSCS are anticipated difficult airway, possibilities of aspiration, problems with extubation, emergence, and recovery from GA. A rapid sequence induction is considered standard of care for GA in LSCS. Having two anesthesiologists is therefore mandatory during induction of GA for LSCS. Clinicians can choose between thiopentone sodium or propofol for intravenous induction and rocuronium bromide or succinylcholine for facilitating neuromuscular blockade for endotracheal intubation.[12] Technological advances made in airway management equipment's, better understanding of obstetric airway, and simulation-based teaching of failed airway management in obstetrics could have possibly led to better outcomes and lesser adverse events when GA is employed for LSCS.[13]

Mushambi et al. reviewed 138 publications (152 cases) to gather evidence on the management of the anticipated difficult airway in the pregnant woman.[14] The authors laid special emphasis on antenatal multidisciplinary planning and awake tracheal intubation. The authors concluded that multidisciplinary approach and teamwork is important when dealing with maternal airway so as to avoid catastrophe. The advantages and safety of RA for LSCS have been established beyond doubt. However, there arises a situation when RA fails or is patchy and is not enough for performing LSCS. In such situation, GA is inevitable. In a 5-year audit of obstetric anesthesia for LSCS, Kinsella reported that 63% patients received SAB, 26% received epidural (top-ups), combined subarachnoid block-epidural anesthesia (SAB-EA) in 5% and GA in 5% cases.[15] At the same time, Afolabi and Lesi concluded in a systematic review in Cochrane Database that there was no evidence to show that RA is superior to GA in terms of major maternal or neonatal outcomes.[16]

A category 1 LSCS is a situation when there is an immediate threat to mother or baby's life. In presence of a favorable maternal airway, a rapid sequence induction of GA with an experienced anesthesiologist could be faster than a spinal anesthesia.[17] Krom et al. demonstrated that the mean time to induction with rapid sequence induction was 100 s (87–114) compared with 9 min (7–11) min for awake fibreoptic intubation (P < 0.0001) and 6.3 min (5.4–7.2) for spinal anesthesia (P < 0.0001).[18] Although GA provided faster surgical conditions for LSCS than RA for category 1 LSCS in spite of higher morbidity and mortality, rapid sequence spinal anesthesia is now gaining momentum in many centers.[1920] Patients undergoing LSCS under GA had more blood loss and had a larger proportion of newborns with 5-min Apgar scores <7 for spinal group.[21] Fernandes and Dyer emphasized that urgent LSCS required an individualized approach and the type of anesthesia should be based not only upon urgency of LSCS but also patient factors.[22]

This study has several limitations. First, it was a retrospective analysis due to which bias could not be addressed. We followed by all patients for 4 weeks after LSCS assuming that in case, there were any postoperative issues including respiratory complications, they would report to the same hospital or some hospital under the Ministry of Health. If this was true, any visit would be documented in the electronic medical records system that is standard all over the country. In case the patient visits a private hospital, we would not know any details. We divided patients who underwent LSCS under GA versus neuraxial anesthesia. The category of urgency of LSCS was not compared because as per the records, the entries were incomplete, did not gather definitive data of indication of emergency LSCS such as placenta accreta, abruptio placenta, and fetal distress. We broadly analyzed the data as GA for emergency situation or GA on maternal request. Moreover, we did not compare the fetal outcomes after GA or RA. This is a major limitation of this study.

CONCLUSION

RA for LSCS is indeed safe, provides maternal satisfaction, excellent perioperative analgesia, and lesser incidence of postoperative nausea/vomiting. GA for LSCS could be safer without any pulmonary complications if there is proper airway planning, if case is attended by at least two Anesthesiologist's, if adequate fasting period is observed for elective LSCS, and patients are monitored after surgery. The anesthetic technique should be planned based on genuine maternal and fetal indication, should be individualized, with focus on safe maternal and fetal outcomes.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.