Intra-Dialytique Hypotension: Prevalence and Associated Factors in 2 Haemodialysis Centres in Senegal ()
1. Introduction
Intra-dialytic hypotension (IDH) has a variable definition depending on the learned academies. There are liberal definitions that require only a minimal fall in systolic blood pressure (SBP) [1] [2] and strict definitions that require a combination of clinical event and nursing intervention [3] [4] [5]. For example, the European Best Practice Guidelines (EBPG) and the Kidney Disease Improving Global Outcomes (KDOQI) have defined it as a fall in SBP ≥ 20 mmHg or a fall in mean arterial pressure (MAP) of at least 10 mmHg associated with a clinical event and the need for nursing intervention [3] [4] [5].
Clinical events are defined as the presence of nausea, dizziness, fatigue, cramps, loss of consciousness or any other complaint related to the dialysis procedure, as judged by the patient and/or the nurse and/or physician [3] [4] [5]. Nursing interventions have been defined as temporary or permanent interruption of ultrafiltration, Trendelenburg position, administration of intravenous fluids and/or discontinuation of the haemodialysis session [3] [4] [5]. IDH is a common complication in haemodialysis with a prevalence ranging from 20% to 50% depending on the study [5] [6]. It is an important cause of morbidity and mortality, especially cardiovascular [3] [7]. It occurs mainly during dialysis when the elimination of plasma fluid by ultrafiltration exceeds the vascular filling rate [8]. It is associated with several risk factors such as: large ultrafiltration volume, age over 65 years, female gender, diabetes, Hispanic ethnicity, longer dialysis time, increased body mass index (BMI), low pre-dialysis SBP [8] [9] … In Senegal, a study conducted by Fotso (2015) defining IDH by a drop in SBP > 20 mmHg, reported a prevalence of 31.4% [10]. This study aimed to assess the prevalence of IDH according to the EBPG definition and to identify its associated factors.
2. Patients and Methods
We carried out an observational, multicentre and looking-forward study of descriptive and analytical purposes over a 4-week period (16 November to 12 December 2020) at hemodialysis center of Ziguinchor in the southern of Senegal. All chronic haemodialysis patients with at least 2 sessions per week and a duration of 180 minutes, who consented to participate in the study and aged over 15 years were included. Data collection was done with pre-established forms. The first form provided information on epidemiological, medical history and comorbidities, initial kidney disease, paraclinical and therapeutic data. These data were considered as potential factors associated with IDH. The second form provided information on blood pressures (before each session, at 30, 60, 120, 180 and 240 minutes of each session), dialysis data, clinical manifestations of IDH, and nursing interventions. HID was defined according to the EBPG [3]. A patient was considered to be hypotensive when they experienced hypotensive episodes during more than 25% of their haemodialysis sessions. Inter-dialytic weight gain (IDWG) was defined as low if <4% and high if >4% of baseline weight. The Kidney Disease Improving Glogal Outcomes (KDIGO) guidelines were used for anaemia, calcemia, phosphoremia [11].
The variables were entered and analysed with Epi-info version 7.2.2.2 and SPSS software version 23.0.0. Descriptive results are presented as means and standard deviations for quantitative variables and as proportions for qualitative variables. The Chi-2 independent test allowed to compare quantitative variables by univariate analysis. The significance threshold was retained for a p-value < 0.05.
The protocol was approved by the Research Ethics Committee of the Faculty of Medicine, Pharmacy and Dentistry of Sheikh Anta Diop University. The ethical approval was registered under the number CER/UCAD/AD/MsN/10/2020.
3. Results
Fifty patients were included in the study with 1955 measurements recorded during 568 haemodialysis sessions performed (Figure 1). The mean age of the patients was 43.84 ± 12.10 years with a sex ratio of 0.85. The mean duration of dialysis was 68.78 ± 46.66 months. The other quantitative and qualitative data of the patients are given in Table 1 and Table 2 respectively.
IDH was noted during 12 out of 568 haemodialysis sessions, accounting for a prevalence of 2.11%. Four (4) patients underwent episodes of IDH standing for 8%. One patient was hypotensive (IDH episode during 6 haemodialysis sessions). Fatigue was noted in 41.66% (5/12) and yawning in 25% (3/12) of the sessions with IDH (Figure 2). Trendelenburg position and normal saline infusion were
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Table 1. Distribution of the 50 patients of the study population according to sociodemographic data and dialysis parameters.
CGN: Chronic Glomerulonephritis; CTNI: Chronic Tubulo-Interstitial Nephropathy; IDWG: Interdialytic Weigh Gain.
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Table 2. Distribution of the 50 patients of the study population according to paraclinical data.
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Figure 2. Distribution of the 12 haemodialysis sessions with hypotensive episodes according to clinical hallmarks.
performed during all IDH episodes. Discontinuation of haemodialysis was required in one patient. Permanent or temporary discontinuation was required in 2 patients each.
Hypertension, Interdialytic weigh gain (IDWG) > 3 kg, anemia and hypoalbuminemia were significantly associated with the occurrence of HID with respective p values of 0.047, 0.044, 0.042.
4. Discussion
Using the EBPG definition, IDH was noted in 2.11% of 568 haemodialysis sessions. In the literature, the prevalence of IDH varies depending on the definition used. In 2014, V. Bergur et al., using the same definition, reported a prevalence of 31.1% [8] which is much higher than in our study. Unlike, the studies conducted by Bossola and Akhmouch and their co-workers reported a prevalence of 5% and 11.5% respectively [4] [11]. In Mali, Boubacar et al. reported a prevalence of 3.78% [12] which is almost similar to ours. The low prevalence of IDH in our study can be explained by the small sample size and our short follow-up time compared to the studies of Bergur and Bossola [4] [8]. Our study population was younger (43.84 ± 12.10 years Vs 64.1 ± 15.7 years), with fewer comorbidities and lower IDWG (1.8 ± 0.86 kg Vs 4.25 ± 2.24 kg). In our study, HBP, IDWG > 3 kg, anaemia and hypoalbuminemia were significantly associated with the occurrence of IDH. Johanna et al. reported that female gender, obesity, hypoalbuminemia and high ultrafiltration rate were associated with the occurrence of IDH [13]. Bergur et al. noted that age > 65 years, female gender and high IDwg were associated with the occurrence of IDH [8]. High IDWG sometimes explains why the recommended ultrafiltration rate in patients (10 ml/kg/H) is exceeded, thus partly favouring the occurrence of IDH, also hypoalbimunaemia leads to a decrease in plasma refeeling, thus resulting on IDH.
Fatigue was noted in 41.66% followed by yawning in 25%, nausea ± vomiting and cramps in 16.16% each. Johanna et al. reported the same symptoms but in different proportions with cramps (41.24%), followed by dizziness and yawning (29.53%), fatigue (16.03%) and nausea ± vomiting (14.56%) [14]. All these clinical hallmarks reflect contraction of the extracellular fluid, most often secondary to excessive ultrafiltration. Trendelenburg position and normal saline infusion were performed in all episodes of IDH. Our results differ from those of Johanna et al. [13] with Trendelenburg position and fluid administration being performed in 81.9% and 54.49% of their IDH sessions respectively.
Prevention is an important part of the management of IDH and has been a problem for a long time with the lack of consensus. With the improvement of haemodialysis techniques, prevention strategies for IDH are better known. Preventive measures include increasing blood pressure during dialysis can be achieved by lowering the temperature of the dialysate, using BVM biofeedback, whereby the dialysis monitor-generator automatically adjusts the ultrafiltration rate according to the relative blood volume, limitation of the IDWG by respecting the measures recommended by the nephrologists, the respect of the therapeutic compliance especially the hydrosodic restriction to limit the IDWG, the respect of the hourly ultrafiltration rate which should not exceed 10 ml/kg/H…
Our study has limitations, notably the small size of our population and the short follow-up time of our patients (4 weeks).
5. Conclusion
The prevalence of IDH according to the EBPG definition was low. However, it is an important cause of morbidity and mortality, especially cardiovascular involvement, and the factors associated with its presence have been clearly identified. Prevention is an important part of management.