Can Prep for Colonoscopy Cause High Blood Pressure

J Gastrointestin Liver Dis. Writer manuscript; available in PMC 2013 Mar 22.

Published in final edited form as:

PMCID: PMC3605721

NIHMSID: NIHMS439827

Anti-Hypertensive Therapy and Gamble Factors Associated with Hypotension during Colonoscopy under Conscious Sedation^*

Abstruse

Background & Aims

Pre-operative employ of select antihypertensive therapy has been associated with peri-operative hypotension in the surgical setting. Our aim was to determine the effect of anti-hypertensive medications on blood force per unit area (BP) and procedural outcomes in gastrointestinal endoscopy.

Methods

Our study was a prospective, cross-sectional survey of outpatients undergoing colonoscopy with conscious sedation. We enrolled patients with hypertension that took anti-hypertensive medications within 24 hours of the process and patients without hypertension that were non on BP-lowering agents. We recorded mean BP prior to, during, and afterward the procedure.

Results

626 patients (338 males; hateful age 56.0 ± x.4 years) were enrolled, and 158 patients were on anti-hypertensive therapy. There were 57 patients who developed hypotension, defined as systolic BP <90 mmHg and/or diastolic BP <60 mmHg, during the colonoscopy. Taking a BP medication, regardless of class, was not associated with an increased risk of procedural hypotension (all p >0.05). Historic period, trunk mass index, gender, duration, fentanyl dose, midazolam dose, and co-morbidities (asthma, chronic obstructive pulmonary disease, congestive eye failure, coronary artery affliction) were also non associated (all p >0.05). Instead, a lower pre-process systolic BP (OR=0.97, 95% CI=0.95–0.99; p=0.004) and diastolic BP (OR=0.95, 95% CI=0.92–0.97; p<0.001) were identified as the only run a risk factors.

Conclusion

Patients should go along their anti-hypertensive therapy leading up to endoscopy. A lower pre-procedure BP is the main gamble factor for procedural hypotension in patients undergoing colonoscopy with conscious sedation. Hereafter studies should explore other factors, such equally bowel preparation, that can affect pre-procedure BP.

Keywords: Colonoscopy, blood pressure, cardiopulmonary status, sedation

Introduction

Patient sedation is standard do for gastrointestinal endoscopy. In the Usa, 98% of upper and lower endoscopic examinations are performed with sedative medications [1]. Three quarters of these procedures are washed nether conscious sedation, while the remaining are performed using deep sedation [one, 2]. The apply of allaying agents is on the ascension worldwide, although rates vary greatly across continents [3]. Sedation is generally safe, but associated cardiopulmonary events remain a leading cause of morbidity and mortality [4]. Cardiac and pulmonary complications related to sedation, such as hypotension and hypoxemia [5–8] have been reported with an overall frequency of 90 per ane,000 procedures [iv].

There are currently no prove-based guidelines in endoscopy regarding whether anti-hypertensive therapy should be continued prior to test. The American Higher of Cardiology, American Heart Association, and the European Society of Cardiology suggest caution in the continuation of angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) in the morning of not-cardiac surgery under anesthesia [9, 10]. Other authors believe that diuretics should be held as well pre-operatively [11]. Patients on ACE inhibitors and ARBs appear to be at college gamble of intra-operative hypotension [12–xv], while patients on diuretics can develop cardiac arrhythmias from electrolyte imbalances [xi]. Recommendations that are endorsed for surgery have non been fully evaluated for gastrointestinal endoscopy. Therefore, the goal of this prospective study is to determine the touch on of anti-hypertensive medications on blood pressure and procedural outcomes.

Patients and methods

Overview

This study was a prospective, cantankerous-exclusive survey of outpatients undergoing colonoscopy for any indication at Temple Academy Hospital'south Digestive Diseases Centre (Fig. 1). We did not include inpatients or any patient felt past the investigators to have an urgent or emergent need for colonoscopy. We only studied examinations performed under the administration of conscious sedation with fentanyl and midazolam (Versed, Baxter, Deerfield, IL). Patients who had a history of hypertension or had taken an anti-hypertensive medication within 24 hours of the process were identified. Patients who were on anti-hypertensive medications, simply were non-compliant or had non taken them within 24 hours of the colonoscopy, were considered to be off therapy and excluded. Patients undergoing multiple procedures (east.1000. colonoscopy with upper endoscopy), receiving propofol or supplemental sedatives (e.g. diphenhydramine), or who had had an incomplete colonoscopy (due east.grand. aborted endoscopic exam due to poor bowel grooming) were excluded from assay. Patients with current benzodiazepine or narcotic medication use, decompensated liver affliction, diarrhea, inflammatory bowel disease, or stop phase renal affliction on dialysis were also excluded. All patients received a bowel preparation with polyethylene glycol solution (Golytely, Braintree Laboratories Inc., Braintree, MA) in the day prior to colonoscopy.

Patient enrollment into the study over eight months.

Blood pressure medications

Upon arrival at the pre-procedure area, all patients were evaluated by a registered nurse and dr. to analyze by medical history and to reconcile current medications. Co-morbidities, which included asthma, chronic obstructive pulmonary disease (COPD), congestive centre failure, and coronary artery illness, were documented. For patients taking anti-hypertensive medications, farther details (name, dose, final time medication taken) were gathered. If a patient did not recollect the name or dose of an anti-hypertensive drug, review of electronic medical records and a call to the patient's pharmacy were performed. We restricted our inclusion criteria to patients taking anti-hypertensive therapy to the following classes: ACE inhibitor, ARB, beta blocker (BB), calcium channel blocker (CCB), and diuretic. Drugs from other classes were rarely used in our patients, and we anticipated besides few patients for a meaningful assay.

Pre-procedure

Patients were affixed with a Masimo SET pulse oximeter (Masimo Corporation, Irvine, CA), cardiac leads for continuous electrocardiographic monitoring, and an automatic blood pressure gage. These were connected to a Datascope Passport 2 monitor (Datascope Corporation, Fairfield, NJ) throughout the patient's stay. Vital signs (blood pressure, heart charge per unit, respiratory rate, oxygen saturation) were charted automatically in Provation MD software (Provation Medical, Minneapolis, MN) every iv minutes. Pre-procedure vital signs were defined as all readings from the time the patient was connected to the Datascope Passport 2 monitor in the pre-procedure area until the starting time of sedation in the endoscopy room.

Procedure & post-procedure

During colonoscopy, total doses of fentanyl and midazolam were documented. Intravenous normal saline was co-administered with sedation and afterwards run at a rate of 150 mL per hour throughout the examination. Procedure vital signs were all readings betwixt the commencement of sedation and the "scope out" time documented past the nurse. Mail service-procedure vital signs were all readings later on the colonoscope had been withdrawn until the patient was discharged from the recovery area.

Hypotension & adverse events

The hateful of the vital sign readings for the pre-, peri-, and post-procedure periods were used for assay. Hypotension was defined as a systolic blood pressure <90 mmHg and/or a diastolic claret force per unit area <60 mmHg. These parameters were selected because other authors have used these in the past when studying physiologic changes during colonoscopy with conscious sedation [16, 17]. There is otherwise no standard definition for intraoperative hypotension [18]. Agin cardiopulmonary events were instances in which either the patient became symptomatic (e.g. chest pain, palpitations, shortness of jiff) or required medical intervention (e.yard. early termination of the procedure, pharmacotherapy) in the judgment of the attending dr..

Statistical analysis

Univariate comparisons of categorical and continuous predictor variables were accomplished using the chi-square test or independent samples t-test respectively. Nosotros performed binary logistic regression analyses to await for variables associated with the presence or absence of procedural hypotension. To create the model, we used sequential forward conditional assay by entering predictor variables from the univariate analysis with a p-value <0.05. From this analysis, the odds ratios and 95% conviction intervals of the odds ratios were determined. Information was recorded in Microsoft Excel (Microsoft Corporation, Redmond, WA), and SPSS version nineteen (IBM, Armonk, NY) was used for data analysis. All p-values were from 2-tailed calculations.

Results

Overall study population

During the consecutive viii month period, 626 outpatients (mean age 56.0 ± 10.four years) were prospectively enrolled into the study (Table I). The bulk of our report population was male (54.0%), black (59.6%), and had an American Society of Anesthesiologists (ASA) class Two physical status (83.9%). Overall, mean pre-process systolic blood pressure (135.0 ± sixteen.7 mmHg), diastolic blood pressure (79.3 ± 12.0 mmHg), middle rate (73.6 ± 11.6 beats per minute), respiratory charge per unit (fifteen.7 ± 3.1 breaths per minute), and oxygen saturation (98.vii ± one.6%) were within normal range.

Table 1

Characteristics of 626 report patients.

Demographics/Pre-Procedure Variables
Age (mean years ± SD)	56.0 ± 10.4
Body Mass Index (kg/chiliadii ± SD)	28.9 ± 5.3
due north (%)
Males	338 (54.0)
Ethnicity
White	114 (eighteen.two)
Blackness	373 (59.6)
Hispanic	110 (17.six)
Asian	21 (3.4)
Other	8 (ane.iii)
ASA Physical Status Form
I	84 (thirteen.4)
II	525 (83.nine)
III	12 (one.ix)
IV	0 (0.0)
Blood Pressure Medication Class
≥1 Medication	158 (25.2)
Multiple (≥2 Medications)	133 (21.2)
ACE inhibitor	78 (12.5)
CCB	69 (11.0)
Diuretic	69 (eleven.0)
BB	47 (7.5)
ARB	28 (four.5)
Co-Morbidities
Asthma/COPD	45 (7.2)
Coronary Avenue Illness	12 (ane.9)
Congestive Middle Failure	6 (1.0)

There were 158 patients who had a known diagnosis of hypertension and had taken an anti-hypertensive medication within 24 hours of the colonoscopy. Fifty ix of these patients (37.iii%) had taken their medications within 6 hours of the process. In that location were 133 patients (84.1%) on two or more than agents for blood pressure control. The three most common anti-hypertensive medications were ACE inhibitors (12.5%), calcium channel blockers (11.0%), and diuretics (eleven.0%).

There were 468 individuals who did non have a known diagnosis of hypertension and were non on any medications that could potentially lower their claret pressure. In this grouping, one procedural complication was documented – a 57 year onetime male developed bradycardia during the colonoscopy that responded to atropine. His pre-, process, and post-procedure blood pressures ranged from 118–140 mmHg over 64–90 mmHg. His respiratory rate and oxygen saturation were within normal limits. The patient otherwise completed the endoscopic examination.

The comparison of cardiopulmonary condition and procedural variables in patients with and without hypertension yielded two statistically significant differences (Table II). The 158 patients with hypertension had a college pre-process systolic claret force per unit area (p<0.001) and required less fentanyl during the colonoscopy (p=0.02) than the 468 patients without hypertension. There were otherwise no differences in other pre-procedure vital signs and procedural variables.

Table Ii

Cardiopulmonary status and procedural variables of 626 study patients.

	Patients with Hypertension (n = 158)	Patients without Hypertension (northward = 468)	P Value
Pre-Process Vital Signs (mean ± SD)
Systolic Blood Pressure (mmHg)	143.half dozen ± 16.eight	132.1 ± 15.7	<0.001
Diastolic Blood Pressure (mmHg)	80.8 ± 12.2	78.8 ± 12.0	0.08
Center Charge per unit (beats per minute)	75.0 ± 11.8	73.1 ± 11.5	0.07
Respiratory Rate (breaths per minute)	15.7 ± iii.ii	15.vii ± iii.one	0.91
Oxygen Saturation (%)	98.6 ± 1.v	98.7 ± 1.6	0.34
Process Variables (mean ± SD)
Duration (minutes)	23.iii ± 9.0	23.0 ± 9.iv	0.73
Fentanyl Dose (mcg)	100.5 ± 30.5	107.iii ± 32.3	0.02
Intravenous Fluids (mL)	353.3 ± 207.4	347.seven ± 185.0	0.75
Midazolam Dose (mg)	5.4 ± ane.9	5.vii ± 2.1	0.17

Anti-hypertensive therapy in procedural hypotension

Of the overall population of 626 patients, there were 57 patients (twoscore females; mean historic period 54.5 ± 11.9 years) who developed hypotension, which was defined as systolic blood pressure level <90 mmHg and/or diastolic claret force per unit area <sixty mmHg, during the colonoscopy (Table 3). There were no differences (all p >0.05) in the use of anti-hypertensive therapy amid the five medication classes between the 2 groups. Of the 57 patients who developed procedural hypotension, 12 patients (21%) were on blood pressure-lowering medications. Vii patients were on a single antihypertensive agent, and each of the medication classes was represented. Four patients were on either a two or iii drug combination therapy, while one patient was on a regimen that included medications from all five anti-hypertensive classes.

Table Iii

Variables associated with procedural hypotension.

	Univariate			Multivariate*
Mean ± SD	Procedural hypotension (n=57)	No procedural hypotension (n=569)	P Value	Slope	Odds Ratio	95% CI	P Value
Age (years)	54.5 ± 11.9	56.2 ± 10.two	0.23
Torso Mass Index (kg/m2)	27.vii ± 5.1	29.0 ± five.iii	0.08
Female Gender (%)	70.2	52.four	0.01	0.58	0.56	0.thirty–ane.05	0.07
Procedure (hateful ± SD)
Duration (minutes)	23.iv ± viii.4	23.1 ± 9.4	0.89
Fentanyl dose (mcg)	106.i ± 33.5	105.5 ± 31.9	0.73
Midazolam dose (mg)	v.7 ± 2.3	v.half dozen ± two.0	0.78
Pre-procedure SBP (mmHg)	123.two ± 15.viii	136.2 ± 16.iii	<0.001	−0.03	0.97	0.95–0.99	0.004
Pre-procedure DBP (mmHg)	68.9 ± xi.0	80.iv ± 11.seven	<0.001	−0.06	0.95	0.92–0.97	<0.001
Medications (%)
ACE inhibitor	10.5	12.7	0.64
ARB	5.three	4.4	0.76
BB	8.8	7.four	0.70
CCB	7.0	11.four	0.31
Diuretic	5.3	11.6	0.xv
Co-morbidities (%)
Asthma/COPD	10.five	half dozen.9	0.31
Congestive heart failure	one.8	0.9	0.52
Coronary artery disease	ane.eight	ane.9	0.93

Univariate factors in procedural hypotension

Univariate analysis (Tabular array III) revealed an association betwixt the female gender and procedural hypotension (p=0.01). In addition, patients who developed procedural hypotension had a lower systolic blood pressure (123.2 ± 15.8 vs. 136.ii ± sixteen.3 mmHg; p<0.001) and lower diastolic claret pressure (68.9 ± 11.0 vs. fourscore.4 ± xi.7 mmHg; p<0.001) prior to colonoscopy than those who did not develop procedural hypotension. There were no differences (all p>0.05) in the remaining demographics (historic period, body mass alphabetize), elapsing of colonoscopy, fentanyl dose, midazolam dose, or the prevalence of co-morbidities (asthma, COPD, congestive heart failure, coronary artery affliction) betwixt the two groups.

Multivariate factors in procedural hypotension

When controlling for other model variables and factors using multivariate logistic analysis (Table III), only pre-procedural systolic blood pressure level (OR=0.97, 95% CI=0.95–0.99; p=0.004) and diastolic blood pressure (OR=0.95, 95% CI=0.92–0.97; p<0.001) were inversely associated with the development of procedural hypotension. After decision-making for other model variables, gender was not associated with hypotensive episodes (OR=0.56, 95% CI=0.30–1.05; p=0.07).

Intravenous fluid administration

The 57 patients who developed hypotension during the endoscopic examination received a greater volume of intravenous normal saline than the remaining 569 patients (383.3 ± 182.viii vs. 345.7 ± 191.3 mL; p=0.16). The departure was not statistically significant.

Discussion

Our study of a large sample of outpatients undergoing colonoscopy with witting sedation found that taking an anti-hypertensive medication prior to test was non associated with procedural hypotension. Moreover, age, body mass index, gender, duration, fentanyl dose, midazolam dose, and the presence of co-morbidities (asthma, COPD, congestive heart failure, coronary artery illness) were also not significant predictors. Instead, lower pre-procedure systolic and diastolic blood pressures were the primary contributing variables. Our findings add together to the literature available on the effect of anti-hypertensive therapy on blood pressure, in addition to the identification of adventure factors for hypotension, during gastrointestinal endoscopy.

Blood pressure-lowering medications seem to play less of a role in procedural hypotension. In fact, the majority of our patients who experienced a hypotensive episode were non on anti-hypertensive agents. Findings from our study suggest that taking anti-hypertensive therapy prior to the examination, regardless of medication course, did not increase the risk of developing hypotension during the colonoscopy. However, the use of anti-hypertensive medications, particularly ACE inhibitors and ARBs, in the pre-operative setting has been shown to increase the incidence of intraoperative hypotension in a variety of surgeries under anesthesia [12–xv]. These particular agents, in add-on to the blood force per unit area-lowering effect of sedation, antagonize the renin-angiotensin system (RAS) that is vital in maintaining intra-operative arterial pressure level [19, 20].

1 prospective study of 308 patients showed that patients who took an ACE inhibitor or ARB within x hours of not-cardiac surgery developed more frequent hypotension during the first 30 minutes of coldhearted induction [xiii]. These medication classes were found to be more responsible for the fall in blood pressure in a subsequent study, when the hypotension responded to a vasopressin arrangement agonist rather than a conventional pressor [12]. The contrast in our results from the surgical literature is likely due to differences in class of sedative agents and duration of the procedure. The longer duration of the procedure and the use of full general anesthesia for surgical cases are likely to intensify the suppression of the RAS, and therefore, disrupt the body's power to maintain a stable blood pressure.

Results from our study demonstrate that doses of fentanyl and midazolam are not significant contributors of hypotension. Midazolam can have greater effects on the cardiovascular system than fentanyl [6, 21] and has been linked to a reject in blood pressure during colonoscopy [vii, 17, 22]. The difference in these results may be attributed to the employ of another offshoot sedative or dissimilarities in the monitoring of cardiopulmonary status. Our findings further identify that having a lower initial blood pressure prior to endoscopy potentially increases the take a chance of procedural hypotension. Since this association appears less related to anti-hypertensive medications, i likely explanation is that a lower pre-process blood pressure could exist a consequence of the colonoscopy bowel training [23]. Fluid deficits that lead to dehydration and hypotension are an increasingly prevalent complication amid bowel purgatives [24]. A future study could explore this possibility.

Our study has several limitations. Our results apply to patients receiving conscious sedation with fentanyl and midazolam, merely we did not include patients who received deep sedation with propofol. Nonetheless, we excluded these cases, because propofol is usually reserved for patients with substantial cardiovascular or pulmonary disorders. For like reasons, we excluded inpatient procedures. Secondly, in that location is a potential for recall bias concerning medication history, although this should exist non-differential. Some other limitation is the assistants of intravenous fluids at a standard rate in all patients without respect to blood pressure. Fluid resuscitation is performed with the goals of hydration and maintenance of blood pressure, just it has been shown in a previous study to non preclude hypotension in patients undergoing colonoscopy [25].

Conclusion

Our data propose that patients should keep their claret pressure medications, including ACE inhibitors and ARBs, in the morning time leading up to endoscopy. We found that anti-hypertensive therapy taken prior to examination was not associated with procedural hypotension, even afterwards controlling for factors such as sedative dose. Instead, a lower pre-procedure blood pressure is the primary risk factor for the evolution of hypotension during colonoscopy nether conscious sedation. Future studies should focus on other groups of endoscopic patients, such equally inpatients, those undergoing circuitous lengthy procedures, and those with severe co-morbidities. Another potential expanse of interest is the relationship between bowel purgatives and their effect on BP earlier colonoscopy.

Footnotes

^*Preliminary data was presented as an oral presentation at the Annual Scientific Coming together of the American College of Gastroenterology in Washington, DC on Nov two, 2011.

Conflicts of interests

None to declare.

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