The impact of novel coronavirus infection on blood pressure variability in patients undergoing painless gastrointestinal endoscopy

Abstract

Objective

This study aims to examine the impact of COVID-19 infection on blood pressure variability among patients undergoing painless gastrointestinal endoscopy.

Materials and methods

We conducted an analysis on a cohort of 53 patients who received painless gastroscopy at the First Affiliated Hospital of Zhengzhou University between November 2022 to January 2023. Non-invasive cuff pressure measurements were taken every minute upon the patient's arrival. Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP), and Pulse Pressure (PP) were recorded both 5 min before and after induction. The variability in these parameters was calculated as the standard deviation (SD) over the mean, multiplied by 100%. Patients were grouped based on their history of COVID-19 infection.

Results

Our findings revealed significant differences in blood pressure variability between patients with a history of COVID-19 infection and those without. Prior to, substantial increases in variability were observed in DBP, MAP, and PP, while no significant change was in SBP. Following induction, COVID-19 positive patients exhibited heightened variability in all parameters. The most pronounced changes were seen in Pulse Pressure both before and after induction, suggesting a heightened cardiovascular response in patients with a history of COVID-19. These differences were statistically significant, indicating a clear impact of COVID-19 on cardiovascular stability during endoscopic procedures.

Conclusion

The study underscores the influence of COVID-19 on increased blood pressure variability in patients undergoing painless gastrointestinal endoscopy. These findings highlight the need for vigilant cardiovascular monitoring in COVID-19 affected individuals during similar medical procedures.

Introduction

The COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has triggered a global public health crisis.¹ Over time, the post-acute sequelae of SARS-CoV-2 infection have garnered increasing attention.² T he term "long COVID" has been officially recognized by the US National Institutes of Health to depict the scenario where symptoms persist or new ones emerge for a minimum of 3 weeks after the onset of acute SARS-CoV-2 infection.³ Common symptoms of long COVID include fatigue, insomnia, and fluctuations in blood pressure variability, characterized by postural tachycardia syndrome and orthostatic hypotension.³ Previous research has indicated that patients might continue to experience increased blood pressure variability, even after the resolution of symptoms, following SARS-CoV-2 infection.3, 4, 5 The clinical characteristics of patients undergoing anesthesia after recovering from COVID-19, along with the underlying mechanisms of long COVID, merit further exploration. This study endeavors to explore alterations in blood pressure variability among patients undergoing painless gastrointestinal endoscopy post SARS-CoV-2 infection. By offering insights into clinical practices, it also aims to discuss potential mechanisms linking long COVID with its impact on blood pressure variability.

Materials and methods

Based on existing literature and preliminary experimental results, the significance level was set at 0.05, and the test power at 0.9. Based on calculations using SPSS, it was determined that each group would require 25 patients. Accounting for an expected attrition rate of 20%, an additional 5 patients were included in each group, resulting in a total estimated sample size of 30 patients per group.

The study enrolled patients who underwent painless gastrointestinal endoscopy at the First Affiliated Hospital of Zhengzhou University from January to March. Inclusion criteria encompassed patients with ASA grades I and II, aged 18 to 65, who underwent painless gastroscopy, colonoscopy, or both under general anesthesia without intubation, regardless of their COVID-19 status. Exclusion criteria involved patients with severe cardiac, pulmonary, hepatic, or renal abnormalities, uncontrolled hypertension, or those who had not recovered from COVID-19 during the infection period.

Upon entering the examination room, non-invasive arterial blood pressure was monitored every minute. After five blood pressure measurements, anesthesia was administered following the routine practice of the anesthesiologist. The induction protocol typically involved Ciprofol at 0.2–0.4 mg/kg combined with alfentanil at 5–10 ug/kg, or Ciprofol at 0.2–0.4 mg/kg combined with sufentanil at 0.1–0.2 ug/kg. An additional five non-invasive arterial blood pressure measurements were taken after anesthesia administration and loss of consciousness. Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP), and Pulse Pressure (PP) were recorded throughout the anesthesia process. Mean and standard deviation (SD) were calculated for SBP, DBP, MAP, and PP, with Blood Pressure Variability (BPV) computed as SD/mean×100%.

Patients meeting the diagnostic criteria for COVID-19 according to the ninth edition of the Diagnosis and Treatment Protocol for Novel Coronavirus Pneumonia in China between December 2022 and January 2023 were considered to have a history of COVID-19 infection.

Patients were categorized into two groups according to their history of novel coronavirus infection for comparative purposes. The data recorder was blinded to patients’ COVID-19 history. The records of COVID-19 infection were only added after data collection and analysis had concluded, ensuring an unbiased data collection process.

The experiment has been registered with the China Clinical Trial Center.

Results

During the period from November 2022 to January 2023, a total of 60 eligible patients were initially chosen. Among them, 25 individuals had no history of COVID-19 infection. Within this non-COVID-19 group, 5 patients were subsequently excluded for not meeting the inclusion criteria. Among the 35 patients who had experienced a COVID-19 infection in the past, 2 participants were excluded as a result of requiring pressor support due to post-induction hypotension. This information is visually presented in Fig. 1.

Fig. 1.

Patients included and excluded.

Table 1 illustrates that there were no notable differences in baseline characteristics among all the patients included in the analysis.

Table 1.

Comparison of patient baseline characteristics.

	COVID-19	Non-COVID-19	P value
Number	33	20	/
Age	44.94 ± 14.04	47.65 ± 9.94	0.21
gender(male%)	57.89	51.42	0.55
BMI	23.50 ± 3.50	22.69 ± 2.77	0.39
History of hypertension(true%)	20.00%	17.14%	0.71
equivalent dose of opioid analgesics (morphine)	2.994 ± 1.07	3.350 ± 4.01	0.93
Intraoperative dosage of Ciprofol	20.10 ± 7.08	22.39 ± 7.19	0.928

P ≤ 0.05 is considered to be statistically significant.

As presented in Table 2, significant differences were observed in all aspects of blood pressure variability before induction, except for SBP.

Table 2.

Comparison of blood pressure variability before induction.

	Non-COVID-19	COVID-19	t	P value	Difference (CI95%)
SBP	4.54 ± 3.24	5.68 ± 2.53	-1.45	0.154	-1.14(0.79/−2.73)
DBP	4.49 ± 2.21	6.78 ± 4.25	-2.6	0.012	-2.29(0.89/−4.06)
MAP	3.28 ± 1.98	5.12 ± 2.88	-2.77	0.008	-1.84(0.66/−3.17)
PP	6.09 ± 3.55	9.94 ± 5.91	-3	0.004	-3.85(1.28/−6.43)

P ≤ 0.05 is considered to be statistically significant.

SBP: systolic blood pressure, DBP: diastolic blood pressure, MAP: mean arterial pressure, PP: pulse pressure.

Table 3 displays significant differences in SBP, DBP, MAP, and PP variability after induction between the two groups of patients.

Table 3.

Comparison of blood pressure variability after induction.

	Non-COVID-19	COVID-19	t	P value	Difference (CI95%)
SBP	4.56 ± 1.99	6.59 ± 3.67	-2.63	0.011	-2.03(−3.58/−0.48)
DBP	7.20 ± 3.37	11.20 ± 6.84	-2.87	0.006	-4.00(−6.80/−1.20)
MAP	5.78 ± 2.31	8.08 ± 4.60	-2.42	0.019	-2.30(−4.22/−0.39)
PP	9.96 ± 4.42	14.24 ± 10.23	-2.1	0.041	-4.28(−8.38/−0.18)

P ≤ 0.05 is considered to be statistically significant.

SBP: systolic blood pressure, DBP: diastolic blood pressure, MAP: mean arterial pressure, PP: pulse pressure.

Table 4 illustrates noteworthy significant differences in SBP, DBP, MAP, and PP variability during the overall procedure between the two groups of patients.

Table 4.

Comparison of overall blood pressure variability during overall procedure.

	Non-COVID-19	COVID-19	t	P value	Difference (CI95%)
SBP	8.24 ± 3.08	10.72 ± 3.93	-2.577	0.013	-2.48(−4.42/−0.55)
DBP	9.35 ± 3.15	12.93 ± 4.72	-3.341	0.002	-3.58(−5.74/−1.43)
MAP	8.24 ± 2.45	10.92 ± 3.85	-3.089	0.003	-2.68(−4.42/−0.94)
PP	15.44 ± 6.67	19.78 ± 7.44	-2.198	0.033	-4.34(−8.32/−0.36)

P ≤ 0.05 is considered to be statistically significant.

SBP: systolic blood pressure, DBP: diastolic blood pressure, MAP: mean arterial pressure, PP: pulse pressure.

Table 5 indicates that there were no statistically significant differences in blood pressure changes before and after induction.

Table 5.

The changes in blood pressure before to after induction.

	Covid-19	Non-Covid-19	P
SBP	16.90 ± 9.08	18.28 ± 13.54	0.657
DBP	23.13 ± 5.93	22.40 ± 9.11	0.744
MAP	27.97 ± 5.96	26.88 ± 9.97	0.835
PP	6.05 ± 9.11	6.67 ± 11.18	0.661

P ≤ 0.05 is considered to be statistically significant.

SBP: systolic blood pressure, DBP: diastolic blood pressure, MAP: mean arterial pressure, PP: pulse pressure.

Discussion

Patients with COVID-19 frequently experience persistent symptoms that endure even after respiratory symptoms subside and a negative nucleic acid test is obtained. This condition is often referred to as "long COVID". The World Health Organization defines "post-COVID-19 condition" (long COVID) as symptoms persisting for a minimum of two months, which cannot be attributed to an alternate diagnosis, following the acute phase of SARS-CoV-2 infection. Long COVID patients often endure symptoms such as insomnia, anxiety, fatigue, and an elevation in blood pressure variability.3, 4 In this study, with the exception of BPV of SBP prior to induction, all BPV indicators in COVID-19 patients exceeded those in non-COVID-19 patients. This trend is consistent with the majority of prior research. Although some studies have suggested a decline in blood pressure variability after COVID-19 infection.⁶ we do not view these findings as contradictory to our results, as we will elucidate in the subsequent section.

The novel coronavirus stands apart from other common respiratory viruses due to its distinct feature of having a high affinity for nerve cells, enabling its invasion into the central nervous system where it can persist and inflict damage.5, 7 This unique characteristic is largely attributed to the virus's spike protein (S protein) and its interaction with angiotensin-converting enzyme 2 (ACE2), facilitating its entry into nerve cells.7, 8 The mechanisms driving nerve damage by the virus likely involve direct viral effects, immune responses, inflammation, and other factors. The anatomical locations of such damage could be associated with the hypothalamus or brainstem.1, 9, 10

One outcome of nerve system impairment is the disruption of the autonomic nervous system, marked by inappropriate regulation of heightened sympathetic nervous system activity, as well as diminished activity.5, 9, 10 This dysfunction is evidenced by altered blood pressure variability (BPV) and heart rate variability (HRV), as well as occurrences like orthostatic hypotension and postural tachycardia syndrome.5, 6, 11, 12 Elevated sympathetic nervous system activity results in vasoconstriction, increased heart rate, and relatively elevated blood pressure levels. During less pronounced environmental changes, such as during sleep, blood pressure may fail to adequately decrease, leading to a reduction in blood pressure variability⁶，In more pronounced environmental changes, such as rapid shifts in body position, blood pressure fluctuations tend to amplify, leading to increased blood pressure variability, commonly termed orthostatic hypotension.⁵

In this study, the induction of general anesthesia represented a substantial environmental alteration, resulting in significant blood pressure decrease after induction and a notable surge in blood pressure variability.

This finding corroborates previous research outcomes and can be illuminated through the prior discussion. Consequently, the outcomes of this study do not contradict research that explores decreased blood pressure variability. In this experiment, aside from SBP before induction, the blood pressure variability (BPV) of COVID-19 patients was consistently higher than that of non-COVID-19 patients—whether prior to induction (Table 2), post-induction (Table 3), or across the entire process (Table 4). The heightened BPV observed throughout the process implies that anesthesia induction induces more pronounced circulatory fluctuations in COVID-19 patients. This underscores the importance of anesthesiologists being adequately prepared to manage potential hemodynamic changes, including readying vasopressors and closely monitoring blood pressure, before administering anesthesia to individuals with COVID-19.

Moreover, the absence of a significant difference in blood pressure changes before and after induction (as depicted in Table 5) suggests that blood pressure variability serves as a more sensitive indicator of circulatory changes.

In parallel, our findings revealed that the BPV of DBP surpassed that of SBP and MAP. Specifically, pre-induction values were −2.29 (0.89/−4.06) for DBP compared to −1.14 (0.79/−2.73) for SBP and −1.84 (0.66/−3.17) for MAP. Post-induction values were −4.00 (−6.80/−1.20) for DBP compared to −2.03 (−3.58/−0.48) for SBP and −2.30 (−4.22/−0.39) for MAP. Throughout the entire process, values were −3.58 (−5.74/−1.43) for DBP compared to −2.48 (−4.42/−0.55) for SBP and −2.68 (−4.42/−0.94) for MAP. Generally, DBP is regarded as an indicator of peripheral vascular resistance or tension within blood vessels. The increased variability in DBP aligns with our earlier theoretical discourse.

This study revealed higher blood pressure variability among COVID-19 patients, suggesting that during the anesthesia induction of these patients, it is advisable to consider the use of medications with lesser impact on blood pressure, enhance the meticulous monitoring of blood pressure, and be prepared with vasopressor agents. This approach aims to prevent the occurrence of severe hypotension and its associated adverse consequences following induction.

This study offers valuable insights for clinical practice by further exploring the clinical characteristics of blood pressure variability during anesthesia in COVID-19 patients. Additionally, it provides a reference point for understanding the clinical attributes of COVID-19 patients, especially those with persistent symptoms, and the implications thereof.

However, there are certain limitations to this research. Firstly, the study is conducted within a single center and reflects the medication practices of anesthetic physicians within that specific center. Secondly, non-invasive cuff pressure is employed to represent blood pressure rather than invasive arterial pressure, which could introduce some degree of error. Nonetheless, the trends in blood pressure changes still provide meaningful reference value. Furthermore, it's important to note that data collection is limited to painless gastrointestinal endoscopy procedures in patients without intubation. Complex gastrointestinal endoscopy treatments and cases involving general anesthesia with intubation might yield different results.

At the conclusion of data collection, most patients had been in the recovery phase for a span of 3–6 weeks post-infection. Further research is essential to ascertain the blood pressure variability of patients who were more recently infected or have recovered for a more extended period. This research avenue will be explored in our upcoming observations.

Conclusion

COVID-19 is linked to elevated blood pressure variability among individuals undergoing painless gastrointestinal endoscopy.

CRediT authorship statement

Conceptualization, Z.L.; methodology, D.T.; software, Z.L.; validation, F.Q.; formal analysis, Z.L.; investigation, F.Q.; data curation, Y.H.; writing – original draft preparation, Z.L.; writing – review and editing, J.-j.Y. and D.T.; supervision, J.-j.Y.; project administration, D.T.; All authors have read and agreed to the published version of the manuscript.

Disclosure statement

Informed consent was obtained from all subjects involved in the study.

Ethical statement

The study was conducted in accordance with the Declaration of Helsinki, and approved by the Ethics Committee of First Affiliated Hospital of Zhengzhou University (protocol code 2022-KY-0809-002). This study has been registered in the Chinese Clinical Trial Registry (registration number: ChiCTR2200058488).

Funding

This research received no external funding.

Conflict of interest

Jian-jun Yang and Dandan Tian hold the position of Editor-in-Chief and Editorial Board Member for JATM respectively. They were blinded from reviewing or making decisions for the manuscript. The authors declare that they have no conflicts of interest.

Data availability statement

All study data are included in the article.