The study took place in the medical emergency unit, the medical intensive care unit and the multipurpose intensive care unit of the Sylvanus OLYMPIO University Hospital Center in Lomé, Togo (CHU-SO). The CHU-SO is, according to the health pyramid, a level 3 reference center. It has five major departments: Medicine and medical Specialties; Surgery and surgical specialties; Gynecology and obstetrics; Pediatrics; and Diagnostic assistance (the laboratory and the radiology and imaging department).

This was a cross-sectional and descriptive study with retrospective collection of data over a period of 24 months from January 1, 2022 to December 31, 2023 in the medical intensive care units, the multipurpose intensive care unit and in the emergency unit medical emergencies at CHU-SO.

We included in the study all medical records of hospitalized patients found in the department archives and having:

- Age 18 and over during our study period;

- A renal biological exploration;

- Carried out the first hemodialysis session in an emergency situation.

Not all files of patients who did not have renal biological exploration and/or who performed hemodialysis outside of an emergency situation were included in the study.

Concerning the collection, we first consulted the registers of the departments of the medical emergency unit, medical intensive care unit and multipurpose intensive care unit and selected the medical files of cases of renal pathologies from these departments. We documented these medical files and retained files that had benefited from hemodialysis in emergency situations. The data was collected using a pre-established survey form after reading the files.

The variables studied were:

- Sociodemographic data;

- Clinical data: comorbidities and pathological history, lifestyle, functional signs, duration of progression, general signs and physical signs, regular or irregular medical follow-up;

- Paraclinical data: biological and imaging data;

- Treatments received;

- Indications and location of the first dialysis session (public or private);

- Evolving data: evolving modalities, output mode.

Statistical analysis of the data was carried out with KoBoCollect software version 2.024.12. Processing was done with Word, Microsoft Excel version 2021 and Jamovi 1.6.3 software. The Chi² test was used for the comparison of qualitative variables and the One-Way ANOVA, Godness of Fit tests were used for the comparison of quantitative variables. The significance threshold was set at 5%.

Some operational definitions related to our study:

Blood ionogram standards:

Hospital prevalence

During the study period, 210 cases of kidney failure patients at the dialysis stage were identified, including 120 in medical intensive care, 25 in multipurpose intensive care and 65 in medical emergencies. Among these files, 116 met the inclusion criteria of the study, i.e., a frequency of performing emergency hemodialysis estimated at 55.24%.

This frequency is related to the different services in the study ( Table 1 ).

The average age of the patients was 45.08 years with extremes of 18 and 80 years. The most represented age group was [52 - 68 years] at 37.07% for 43 patients ( Figure 1 ).

Men were represented at 61.21% and women at 38.79% for a sex ratio of 1.58 men to women.

Patients in 84.48% (98) did not have health insurance.

The most common reasons for admission were repeated nausea and vomiting at 21.55% and asthenia at 19.82% ( Figure 2 ). The main signs observed on admission were: dyspnea, edematous-ascitic syndrome in 13.73%, anuria in 11.76%.

Arterial hypertension (HTA) represented 49.14% of the history ( Table 2 ).

The risk factors for kidney disease were represented by: Alcohol at 33.62%, taking infusions 24.14%, self-medication 14.66%, tobacco 10.34% and a sedentary lifestyle at 3.45%.

The most used anti-hypertensive medications before admission were ( Table 3 ).

Renal failure was chronic in 68.97% of patients and acute in 31.03% of cases. The associated signs and pathologies were mainly alteration of general condition, anemic syndrome and alteration of consciousness ( Table 4 ).

The average was 172.79 ± 71 mg/l with extremes of 84 and 724 mg/l. The range of [123 - 223 mg/l] was the most represented in 43.97% (51) of patients ( Table 5 ).

The glomerular filtration rate in patients with chronic renal failure was less than 15 ml/min/kg/m² in 78.45% of patients ( Table 6 ).

The average hemoglobin level was 8.04 g/dl with extremes of 3 and 14 g/dl.

Anemia was noted in 91 patients. This anemia was microcytic in 34 patients, normocytic in 47 patients and macrocytic in 10 patients.

Hyperleukocytosis and leukopenia were found respectively in 25.86% and 8.62% of our patients and 87.5% of the latter were predominantly polynuclear neutrophils.

Thrombocytopenia and thrombocytosis were found in 8.62% and 3.45% of patients respectively.

Hypocalcemia was found in 55.17% of patients and hyperphosphatemia was found in 50.00% of patients ( Table 7 ).

The average proteinuria was 899.96 mg/24 h with extremes of 208.8 mg/24 h and 2010.12 mg/24 h; 55% of proteinuria was between 200 and 1000 mg; 40% between 1000 and 2000 mg; 5% were greater than 2000 mg.

Renal atrophy was the most represented at 66.67% among patients. In 30% of cases, the size of the kidneys was normal and was increased in 3.33%.

Severe malaria and prostate cancer were the main causes of AKI respectively at 8.62% and 3.45%; organic and infectious causes were the main etiologies of AKI respectively at 4.31% and 1. 72%.

Arterial hypertension and HIV were the main etiologies found in CKD in 8.62% and 6.89% of patients respectively ( Table 8 ).

Anuria was found in 5.17% of patients. Urea was greater than 3 g/l in 39.66% of patients; it was between [2.1 - 3 g/l] in 32.76% of patients and between [0.46 - 2 g/l] in 27.58% of patients. Altered consciousness was found in 72.42% of these patients.

Acute lung edema (APO) was found in 34.48% of patients.

Mean serum potassium of 6.37mmol/l ± 2.1 with extremes of 1.79 and 8.17 mmol/l. Threatening hyperkalemia greater than or equal to 7.5 mmol/l was found in 25.86% of patients ( Table 9 ).

The main indication for emergency hemodialysis was poorly tolerated uremia (48.45%); uremic encephalopathy (15.55%); acute lung edema (APO) in 13.58%; threatening hyperkalemia (13.42%) and anuria of 24 hours or more (9%).

Emergency hemodialysis was performed within the first six hours in 7.75% of patients after its indication ( Figure 3 ). The average number of sessions was 3.5 with extremes of 1 and 7 sessions in our hemodialysis patients. The centers carrying out the first emergency dialysis session were private centers in 80.34% and the CHU-SO hemodialysis center in 19.66%. The approach used was the jugular route in 56.03% and the femoral route in 43.97%.

Solutes based on isotonic saline (SSI) and diuretics in general were more widely used at 73.28% ( Table 10 ).

*Low molecular weight heparin.

The clinical evolution of patients after emergency hemodialysis was favorable in 69.83% and unfavorable in 30.17%. The OAP declined to 91.25%.

Paraclinically, uremia was greater than or equal to 2 g/l in 46.55% of patients after the first hemodialysis session. Serum sodium, serum chloride and serum potassium had normalized respectively in 34.48%; 55.17%; 51.72% of cases.

After the hemodialysis sessions, 39.66% of patients were released. The recorded death rate was 37.07%. The causes of death were sudden death and septic shock in 46.51% and 20.93% of patients, respectively.

Poorly tolerated uremia and hyperphosphatemia were linked to the occurrence of death with respectively (P-value of 0.01; P-value of 0.03).

Our study has strengths, limitations and biases to take into account for a proper interpretation of the results.

The main strength of our study is that it is the first of its kind to be carried out in an emergency, intensive care and resuscitation department in Togo.

The limitations were: the study framework, the poor conservation and maintenance of medical records on the one hand and the lack of many additional examinations necessary for the proper monitoring of patients over time. The study setting was monocentric and therefore could not be generalized to the entire Togolese population.

Hospital prevalence

Out of a total of 210 emergency hemodialysis patients, 116 met the inclusion criteria for a hospital prevalence of 55.24%.

This prevalence was higher than that of Selly et al. in Senegal which was 40.68% in 2020 [2] and lower than that of Didier et al. in Ivory Coast which was 68.54% [8] in 2020. This high prevalence rate could be explained by the fact that the CHU SO is the reference hospital with the only public hemodialysis center.

They were dominated by high blood pressure at 49.14% followed by diabetes at 34.48%. Non-dialysis CKD at 28.48% then HIV infection at 6.89%.

These results were similar to those of Ilboudo et al. in Burkina Faso in 2021 in whom hypertension, diabetes and CKD were respectively at 46.15%, 4.62% and 15.38% [9] . Didier et al. in Ivory Coast in 2020 found hypertension, CKD and HIV at 63.9%, 24% and 6.68% respectively [8] .

This rate of CKD patients not on dialysis in our study could be explained by the high cost of treatment and/or the non-accessibility of dialysis centers in our regions. To this we could associate the refusal or non-acceptance of the illness in certain cases.

In our study the most frequent clinical signs in the different departments were: alteration of general condition 85.34% in medical emergencies, alteration of consciousness 53.45% and respiratory distress syndrome 41.38 % in medical intensive care and multipurpose intensive care.

These results were different from those of Didier et al. in whom hypertensive emergencies 64.3%, and neurological disorders 30.1% were the most represented [8] . This could be explained by the delay in consultation, poor follow-up and late initiation of hemodialysis. Some patients are resigned to the high cost of hemodialysis and refuse this treatment. Therefore, they are only taken care of in cases of vital distress.

Chronic renal failure (68.97%) was more represented in our study and acute renal failure was 31.03%.

These results were similar to those of Didier et al. in 2020 in whom: the CRI was 75.3% and the AKI 24.6% [8] ; Rovamalala et al. in Madagascar had higher results with the CRI which was 82.7% [10] . Chronic kidney disease in sub-Saharan Africa progresses silently to become severe and terminal, explaining the discovery sometimes with complications requiring immediate recourse to hemodialysis. Systematic screening seems necessary.

The main causes were: high blood pressure at 8.62% and HIV (HIVAN) at 6.89% were the main causes of CKD. These results were consistent with those of Didier et al. [8] in Ivory Coast in 2020 where chronic glomerulonephritis (CNG) was the main cause of CKD and those of Selly et al. in Senegal in 2020 where nephroangiosclerosis was the main cause at 25.2% [2] . This could be explained by the high rate of history of hypertension and HIV at 49.14% and 6.89% respectively in our study.

In our study, the main indication for emergency hemodialysis was poorly tolerated uremia (48.45%); uremic encephalopathy (15.55%); acute lung edema (APO) in 13.58%; threatening hyperkalemia (13.42%) and anuria of 24 hours or more (9%).

These results varied from one study to another. Thus Lazrak et al. in Morocco in 2011 found a predominance of hyperkalemia (58%) and hyperazotaemia (49.9%) [8] ; Selly et al. [2] in Senegal in 2020 found uremia poorly tolerated (50.47%) and hyperkalemia threatening (40.19%). For Amékoudi et al. in northern Togo in 2022 [11] , these indications were dominated by uremic encephalopathy at 74.19%.

This difference in results in our study can be explained by the predominance of CKD cases not on dialysis due to lack of financial means or refusal to accept the disease, the delay in consultation of our patients who come to admission with a GFR < 15 ml/min associated with signs of uremic intoxication and other complications of CKD on the one hand, and on the other hand the lack of dialysis centers in other regions outside Lomé; patients from these regions therefore came to Lomé at a late stage.

The central venous catheter (jugular 56.03% and femoral 43.97%) was the most used vascular access. This trend was similar in the series of Rova Malala et al. at 100% [10] , Didier et al. at 97.2% [8] , and Selly et al. at 91.5% [2] . These results were consistent with clinical practice where in the context of the urgency of performing hemodialysis, the possible vascular access remains central venous catheterization. Creating an arteriovenous fistula requires planned surgical intervention.

Death was recorded in 37.07% of patients and appears to be very high. This mortality in our context would be related to the late stage of admission of patients with very urgent hemodialysis indications such as cardiogenic OAP, threatening hyperkalemia and uremic encephalopathy. The mortality of hemodialysis patients according to the DOPPS study remains high despite technical progress [4] . This is linked to the vulnerability of patients with renal failure in whom multiorgan failure seems to set in early, putting life at risk. It would be wise for the authorities to require the installation of dialysis units in emergency departments for rapid treatment of these patients.