Anesthesia for manual vacuum aspiration (MVA) is a hot topic in research in gyneco-obstetrical. It is indicated in incomplete abortion for hemostatic purposes as it’s a health problem throughout the world [1] . As reported by the World Health Organisation (WHO), it concerns 20 million pregnancies and approximately 78,000 maternal deaths due to it each year around the world [2] .

Approximately 5 million pregnancies are complicated each year by 34.000 maternal deaths in Africa [3] . To reduce the morbi-mortality, WHO recommends MVA as gynecological practice [4] and narcosis and paracervical block as anesthetics practices [5] for incomplete abortion. A study done in South Kivu (DRC) in 2020 on “inventory of anesthetic practice for endo-uterine evacuation” concluded that WHO current recommendations are respected but the morbi-mortality is relatively high and that opened a necessity of proposal for another anesthetic practice which could solve the problem. It’s in that order that intrathecal spinal analgesia with a posological formula based on weight and height of patients, of 0.1% bupivacaine and fentanyl was proposed as an alternative [6] .

It was necessary to compare that to objective judgment criteria, the efficacy of ketamine narcosis (KET) and intrathecal spinal analgesia (RAS) with main objective to contribute to the improvement anesthetic ECP of incomplete abortion by MVA and specific objectives to determine the sociodemographic, epidemiological and clinical profile of patients, to compare the two practices in terms of analgesic effectiveness, comfort, financial cost and risk of complications occurred and at last to present the levels of satisfaction of patients and practitioners in relation to the two protocols (KET and RAS).

1) Type of Study

This is a prospective comparative study with an analytical aim on 2 parts:

•Descriptive observational aspect with analytical aim (KET): Ketamine Narcosis observation and data collection.

•Experimental component as double-blind randomized non-inferiority clinical trial (RAS): Application of the RAS protocol to improve their practice.

2) Sampling

We want to have exhaustive probability samples for both phases of data collection. The samples will be grouped into 2 study groups:

•KET group: (Neutral): All patients benefiting from endo-uterine aspiration under ketamine narcosis in the selected hospitals will be concerned by this observational phase.

•RAS group: (Witness): All consenters after being informed to do part of the study adhering to the RAS protocol will be affected by this experimental phase.

But, to calculate the estimated size of the sample which should give us statistically reliable results, we proceeded to the average of the results of the sample sizes obtained using the software OpenEpi, XLSTAT and which statistical calculation by the formula of the size of the sample recommended for comparisons of proportions (here our two randomized arms KET and RAS). For all these calculations by software and through the formula, we took the standard power of 80% and a standard error of 5% with a prevalence of KET patients of 32.5% and RAS of 60% in accordance with the literature results for MVA post-abortum.

Thus, the sample sizes were:

(1) For the Open Epi software: N' = 116.

(2) For the XLSTAT software: N" = 268.

(3) For the formula comparing proportions $\text{N}=\frac{2\times \stackrel{\rightharpoonup }{P}\left(1-\stackrel{\rightharpoonup }{P}\right){\left(\text{Z}\alpha /2+\text{Z}\beta \right)}^2}{{\left(P_1-P_2\right)}^2}$ =162 cases or 81 cases per randomized arm.

With:

•P₁: Proportion of patients for whom the judgment criteria are equal to 1 (100%) in group 1 (KET).

•P₂: Proportion for which the judgment criteria are worth 1 (100%) in group 2 (RAS).

•P: Average proportion of patients for whom the judgment criteria are equal to 1 (100%) in the 2 groups (KET and RAS).

•Z/2 and Z: Constants determined by and therefore (Z/2 and Z)² is also a constant determined by the power (1-) and the type I error allowing the null hypothesis to be rejected (H₀).

$\begin{array}{l}N=\frac{N\text{'}+N\text{'}\text{'}+N\text{'}\text{'}\text{'}}{3}=\frac{116+268+100}{3}\\ \text{=}162casesor81casesperrandomizedarm\end{array}$

Taking into account the cluster effect linked to the multicentricity of our study, the inflation factor (IF) allows us to have a sample size to circumvent this flu effect by maintaining as follows

$\text{FI}=\left[1+\left(n-1\right)\right]$

With: n = Average size of a cluster (81 for our study)

p = Interclass correlation coefficient (0.01 for our study because our main judgment criteria are results type)

$\text{FI}=\left[1+\left(81-1\right)\cdot 0.01\right]=1.8$

Hence, the size of our sample after eliminating the flu effect becomes:

${\text{N}}_{\text{cor}}=\text{N}\cdot \text{FI}=162\cdot 1.8=291.6$

And adding 10% loss:

$\begin{array}{l}{\text{N}}_{\text{+at}}:{\text{N}}_{\text{cor}}+10\%{\text{N}}_{\text{cor}}=291.6+29.16=320.32\\ \approx 320casesor160cases/randomizedarm\end{array}$

3) Inclusion Criteria

•KET phase: All patients who received post-abortion endo-uterine aspiration in the selected hospitals during the observational period.

•RAS phase: All patients who, after informed consent, agreed to try the RAS protocol for post-abortion endo uterine aspiration in selected hospitals.

4) Exclusion and Non-Inclusion Criteria

(a) Exclusion criteria: Patient refusal.

(b) Non-inclusion criteria: Any patient, who has benefited from post-abortion endo-uterine aspiration using protocols other than KET and RAS, Patients who received post-abortion endo-uterine aspiration by KET or RAS outside the data collection period.

5) Data Collection and Analysis

The descriptive analysis was carried out using proportion calculations for qualitative variables (frequencies, percentages) and means with their standard deviation (SD) for quantitative variables. Sociodemographic and clinical characteristics as well as patient morbidity were compared between the two anesthetic protocols administered (KET and RAS) using chi-square tests for categorical variables and Student’s t-test for continuous variables. The data were encoded in an Excel 2022 software mask and analyzed using STATA statistical software (version 16.0). P-values less than 0.05 were considered statistically significant.

6) Variables Studied and Judgment Criteria

(a) Variables

•Independent variables: Age, profession, province, hospital of care, ASA class.

Dependent variables: Temperature, Heart rate, respiratory rate, anesthetic protocol, SPO2, nausea, vomiting, delay in waking up, cost of hospital stay post uterine aspiration, Simple verbal pain scale, preparation time, anesthesia time, site of puncture, level of sensory block, modified Aldrete score.

(b) Judging Criteria

•Main: Analgesic effectiveness, patient and practitioner comfort.

•Secondary: Cost, morbi-mortality, complication, duration of post-MVA surveillance.

7) Ethical Considerations

The human materials and data were performed in accordance with the declaration of Helsinki and we received the ethical committee approval referenced UOB/CEM/09/2022.

8) Expected Impact

Adoption and popularization of the RAS protocol with hypobaric Bupivacaine 0.1% and microdose fentanyl adapted to weight and size according to the formulas proposed by this study to contribute to the reduction of morbidity and mortality of post-arbotum endometrial aspirations (incomplete spontaneous abortion) in DRC and elsewhere.

The size of our final sample retained and analyzed is 161 KET cases and 161 RAS cases) or 100.6% of the calculated sample size of 320 cases that were attended. This satisfactory percentage will therefore be able to give us reliable results to compare the 2 protocols KET and RAS according to the set objectives ( Figure 1 ).

At the end of this study, which had the general objective of contributing to the improvement of the anesthetic protocol for incomplete abortions by MVA and specifically to determine the sociodemographic, epidemiological and clinical profile of patients benefiting from MVA post-abortion in DRC, to compare the anesthetic techniques RAS and KET to deduce the effectiveness and finally to present the degrees of satisfaction of patients and practitioners of MVA post-abortion, the results come out that:

•A total of 322 cases were retained and analyzed, or 161 cases were randomized. The majority age group was between 18 - 50 years in the 2 groups KET and RAS and there was no correlation between the two protocols with the sociodemographic characteristics studied, the ASA class, the type of intervention, the history of MVA, the variation of heart rate, of the temperature, the appearance of hypotension, the cost of the anesthetic act and the intensive care unit admission.

•Efficacy of the RAS protocol: judged easier by the anesthetists in 99.38% against 93.79% for KET with significant difference (p = 0.0104), it allows them to be more mobile during the act in 98.76% against 68.32% with a significant difference (p < 0.0001) and the global appreciation was in favor of the RAS protocol in 32.92% against 5.58% for the anaesthetists, 90.68% for patients and 100% for gynecologists who find it excellent in relation to the KET protocol with a significant difference (p < 0.0001)

•KET protocol weaknesses: unconsciousness in all patients during the act and more tachypnea (17.39%) compared to the RAS protocol with difference p = 0.0008, moderate bleeding (55.28%), severe (9.94%) with p = 0.0006, higher material cost with p = 0.0018, the occurrence of vomiting (10.56%), delayed awakening (22.36%), pain after MVA (21.74% ), and a weak change in the modified Abortion score at 30 minutes post-MVA (70.19%) in relation to RAS (81.61%) p = 0.0002.