INTRODUCTION

High-resolution esophageal manometry (HRM) is a diagnostic tool to evaluate esophageal motility dysfunction (1). Currently, HRM is the gold standard to diagnose esophageal motility disorders such as various types of achalasia, esophagogastric junction outflow obstruction, ineffective motility, and aperistalsis (2). The procedure consists of transnasal insertion of a catheter to measure the intraluminal pressure along the esophagus, which is then converted into dynamic esophageal pressure topography plots (3). On these plots, real-time measurements of contractility, sphincter amplitude, and bolus transit are computed, resulting in an overall assessment of esophageal motility using a standardized algorithm such as the Chicago classification system (4). Recent advancements in high-resolution catheters and refinements of the Chicago classification have resulted in significant improvements in diagnosing, prognosticating, and treating esophageal motility disorders (5). With the continued rise in the prevalence of esophageal motility disorders, approximately 32,000 HRM procedures were performed in 2019 under Medicare insurance, with an estimated growth rate of 6.45% annually since 2013 (6).

Generally, HRM is considered a safe procedure with minimal adverse events including mild sore throat, sinus irritation, nosebleed, tachycardia, and increase in blood pressure. A single-center survey study reported that no patients experienced any serious side effects, and 48% had only mild-to-moderate soreness of the throat or nose for several hours after the procedure (7). There have been a few reports of rare complications such as choking from misplacement of catheter through the larynx or a surgical emergency due to perforation (8). Furthermore, previous studies reported only on the safety profile of technically related procedures, such as transnasal manometry before the placement of capsule for esophageal pH monitoring (9), which concluded that transnasal manometry is a safer and more well-tolerated alternative to endoscopy.

Given the high prevalence of esophageal dysfunction in the general population, it is important to understand the safety and tolerability of this gold standard diagnostic tool. While HRM is widely accepted as a safe procedure with various diagnostic uses and high prognostic value, no previous studies have assessed the definite tolerability of the procedure in clinical practice. This study aimed to determine the safety and tolerability of HRM and to investigate reasons for and risk factors of intolerability to help in identifying appropriate patients for HRM and in delivering better counseling to reduce procedure-related anxiety and discomfort.

METHODS Study design and study population

This was a retrospective study that assessed patients' tolerability of HRM tests between January 2005 and February 2022 at Cedars-Sinai Medical Center, a tertiary center in Los Angeles, CA. Participants of all ages were enrolled in the study. This study was approved by the institutional review board of Cedars-Sinai Medical Center (Pro00034154).

Procedure details

Before the scheduled date, patients were given instructions and details on the procedure. Patients were expected to have watched the introductory video and have taken nothing by mouth overnight. All HRM studies were performed in an outpatient setting without sedation, only by gastroenterologists specialized in gastrointestinal motility. One trained nurse was also present in the room to assist with the procedure. Using a long cotton swab, 2% lidocaine was initially applied to the nasal mucosa. The manometry catheter was then guided transnasally into the esophagus and ultimately positioned past the lower esophageal sphincter. Standard solid-state catheters with 4.2-mm outer and 36 circumferential sensors at 1-cm intervals were used for each patient (Medtronic, Ireland).

A manometry study included at least 30 seconds of baseline recording and ten 5 mL saline swallows. Depending on the study findings of patients and severity of esophageal disorder, additional evaluations including provocative testing, solid-food (crackers or apple sauce) swallows, and/or positional changes were performed. Each procedure varied per patient and was untimed. After completion of all tests or on encountering technical difficulties, the manometry catheters were promptly removed.

Data extraction and exclusion criteria

We obtained the procedure reports, demographic information, and relevant clinical data from January 2005 to February 2022 using electronic chart review. Before April 2013, paper procedure reports were scanned onto an online storage system, requiring partial manual input of the data. HRM visits that were scheduled but never started because of logistical, clerical, or technical issues were excluded. For patients who underwent multiple HRM procedures in the study period, only their first manometry was included in the study. Endoscopic placement of the manometry catheter or other methodical variations have been excluded from the study because the primary aim was to assess the tolerance of a standard HRM manometry study conducted in an outpatient setting.

Study outcomes, covariates, and statistical analyses

Our primary outcome of interest was the tolerability of the HRM procedure. Tolerability was determined as a binary variable: tolerated or not tolerated. The reasons for early termination of the procedure included independent patient decision due to discomfort or pain, adverse event, and procedural difficulty, which was defined as the inability to pass the catheter into correct test position. For those who had procedures terminated, we also collected qualitative information on the elements of discomfort, pain, and procedural difficulty that patients experienced. Presumed severe complications of HRM or any adverse events that occurred were also assessed.

We conducted descriptive analysis to investigate the demographic distribution of HRM tolerability among our study population. The relevant covariates gathered from electronic chart review included age during HRM, sex, race, ethnicity, body mass index (BMI), indication diagnoses, comorbidities, and prior surgical history. Race and ethnicity groups were categorized based on the US Census Office of Management and Budget standards (10). Physician-diagnosed comorbidities of anxiety, panic disorder, schizophrenia, depression, post-traumatic stress disorder, cognitive disorders, achalasia, irritable bowel syndrome, and foregut surgical history were found using International Classification of Diseases, Ninth Edition, International Classification of Diseases, Tenth Edition, and CPT codes (11,12). Only diagnoses and surgeries before HRM were included in the study. The χ2 statistic or Fisher test was used for independent univariable analysis for each covariate. Furthermore, we performed multivariable logistic regression to identify any associations between the primary outcome and significant covariates. A 2-tailed P value of less than 0.05 was considered statistically significant. All statistical analyses were performed using Stata/IC version 16.1 (StataCorp LLC) and SAS software, version 9.4 (SAS Institute).

RESULTS

A total of 5,282 HRM procedure reports from January 2005 to February 2022 were accessed using electronic medical records. Of these, 175 repeated procedures were excluded, such that HRM procedures for 5,107 patients were included in the study. As summarized in Table 1, the study population was predominantly female (60.3%), White (80.1%), and non-Hispanic (85.0%). Patients were also categorized by age as children (younger than18 years, 6–17 years of age; n = 52), adults (age 18–79 years; n = 4,767) and seniors (age 80 years or older; n = 288) (Table 1). Of those with recorded BMI measurements (n = 1,617; 31.7% of total), 70.1% had body types that ranged from normal to overweight. Furthermore, in a randomized sample of 400 patients from the study population, most common indications for manometry included refractory gastroesophageal reflux disease (31.8%), dysphagia (29.3%), evaluation for hiatal hernia repair (8.0%), chest pain (5.8%), and achalasia (5.3%) (see Supplementary Table 1, https://links.lww.com/CTG/A914).

Table 1. - Characteristics and demographics of study cohort (N = 5,107) Variable Study cohort n (% of total) Age, yr  <18 52 (1.0)  18–79 4,767 (93.3)  ≥ 80 288 (5.6) Gender  Male 2,030 (39.7)  Female 3,077 (60.3) Racea  White 4,091 (80.1)  Black or African American 429 (8.4)  Asian 222 (4.3)  American Indian/Alaska Native 10 (0.2)  Native Hawaiian/other Pacific islander 14 (0.3)  Other/unknown 341 (6.7) Ethnicitya  Hispanic 687 (13.5)  Non-Hispanic 4,343 (85.0)  Patient declined/unknown 77 (1.5) Body mass index (BMI), kg/m2  <18.5 79 (1.5)  18.5–24.9 588 (11.5)  25–29.9 545 (10.7)  ≥30 405 (7.9)  Unknown 3,490 (68.3)

Data are presented as n (% of total).

aGroups were defined by US Census Office of Management and Budget standards.

Overall, 5,050 patients (98.9%) tolerated the HRM procedure well, and 57 patients (1.1%) did not tolerate the procedure due to procedural difficulties or patient discomfort. As summarized in Table 2, termination rates in female patients were higher than in male patients, but this did not reach statistical significance (1.30% vs 0.84%, P = 0.12) (Table 2). Neither race nor ethnicity had any statistically significant impact on the tolerance of HRM (P values > 0.05). When stratified by BMI, intolerability of HRM was fairly equal in distribution, and there was no significant relationship between BMI of patients and tolerance of the procedure (P = 0.50).

Table 2. - Tolerability of high-resolution esophageal manometry (N = 5,107) Variable Subgroup, n Tolerated, n (%) Not tolerated, n (%) Odds ratioa
Not tolerating HRM [95% CI] P valueb Age, yr 0.003  18–79 4,767 4,720 (99.0) 47 (1.0) Reference  <18 52 49 (94.2) 3 (5.8) 6.15 [1.85–20.43]  ≥ 80 288 281 (97.6) 7 (2.4) 2.50 [1.12–5.59] Gender 0.12  Female 3,077 3,037 (98.7) 40 (1.3) Reference  Male 2030 2,013 (99.2) 17 (0.8) 0.64 [0.36–1.13] Race 0.52  White 4,091 4,047 (98.9) 44 (1.1) Reference  Black or African American 429 423 (98.6) 6 (1.4) 1.31 [0.55–3.08]  Asian 222 221 (99.6) 1 (0.5) 0.42 [0.06–3.04]  American Indian and Alaska Native (AIAN)/Native Hawaiian/Pacific Islander/other/unknown 365 359 (98.4) 6 (1.6) 1.54 [0.65–3.63] Ethnicity 0.65  Hispanic 687 681 (99.1) 6 (0.9) Reference  Non-Hispanic 4,343 4,293 (98.8) 50 (1.2) 1.32 [0.56–3.09]  Patient declined/unknown 77 76 (98.7) 1 (1.3) 1.49 [0.18–12.57] Body mass index (BMI) 0.50  <18.5 79 78 (98.7) 1 (1.3) Reference  18.5–24.9 588 583 (99.2) 5 (0.8) 0.67 [0.08–5.80]  25–29.9 545 542 (99.4) 3 (0.6) 0.43 [0.04–4.20]  ≥30 405 402 (99.3) 3 (0.7) 0.58 [0.06–5.67]  Unknown 3,490 3,444 (98.7) 45 (1.3) 1.02 [0.14–7.49] Comorbiditiesc  Achalasia 158 155 (98.9) 3 (1.9) 1.76 [0.54–55.67] 0.26  Anxiety 321 317 (98.8) 4 (1.3) 1.13 [0.41–3.13] 0.78  Prior foregut surgeryd 40 37 (92.5) 3 (7.5) 7.53 [2.25–25.2] 0.01

Data are presented as n (% of subgroup total).

CI, confidence interval; HRM, high-resolution manometry.

aχ2 statistic was used for univariable comparison analysis. The Fisher exact test was used if cell counts were less than 5 (n ≤ 5).

bP value < 0.05 was considered significant.

cInternational Classification of Diseases,Ninth and Tenth Edition codes: Achalasia (530/K22.0); Anxiety (29,384, 3,000, 3,002, 30,921/F064, F40, F41, F930). Irritable bowel syndrome, cognitive disorders, and other psychological disorders were also included in the analysis: irritable bowel syndrome (564.1/K58.0, K58.9); panic disorder, schizophrenia, depression, post-traumatic stress disorder (295, 297, 298/F20, F22, F23, F24, F28, F29); cognitive disorders of unspecified dementia, Alzheimer disease, Parkinson disease (290, 294/F01, F02, F03).

dCurrent Procedural Terminology (CPT) codes: prior foregut surgery–hiatal hernia repair, paraesophageal hernia repair, Toupet/Nissen fundoplication, Collis gastroplasty (43280–43283, 43325, 43327, 43328, 43330–43338).

Notably, patient age was significantly associated with HRM intolerability (P = 0.003). Both children (6–17 years of age) and seniors (80 years or older) had higher rates of terminated HRM (5.77% and 2.43%, respectively) compared with adults aged 18–79 years (0.99%) (Figure 1). Furthermore, as listed in Table 3, children younger than 18 years had a more than 5-fold increase in not tolerating HRM compared with adults aged 18–79 years, odds ratio (OR) = 5.44, 95% confidence interval (CI) 1.60–18.45; P = 0.007. Similarly, seniors aged 80 years and older were also twice more likely to terminate HRM compared with adults aged 18–79 years, OR = 2.56, 95% CI 1.13–5.76; P = 0.024.

Figure 1.:

Histograms of high-resolution manometry tolerability by age distribution of tolerated high-resolution manometry by age. Y axis ranges from 90.0% to 100.0%, given high tolerability rates across all age groups.

Table 3. - Predictors of not tolerating high-resolution manometry (N = 5,107) Variable Odds ratio
Not tolerating HRM [95% CI] P valuea Age, yr  18–79 Reference Reference  <18 5.44 [1.60–18.45] 0.007  ≥80 2.56 [1.13–5.76] 0.024 Gender  Female Reference Reference  Male 0.67 [0.38–1.20] 0.18 Race  White Reference Reference  Black or African American 1.12 [0.46–2.71] 0.80  Asian 0.41 [0.06–3.04] 0.39  American Indian and Alaska Native (AIAN)/Native Hawaiian/Pacific Islander/other/unknown 1.69 [0.67–4.23] 0.26 Race/ethnicity  Hispanic Reference Reference  Non-Hispanic 1.36 [0.56–3.28] 0.50  Declined/unknown 1.47 [0.17–13.07] 0.73 Body mass index (BMI), kg/m2  <18.5 Reference Reference  18.5–24.9 0.80 [0.09–7.11] 0.85  25–29.9 0.52 [0.05–5.19] 0.58  ≥30 0.65 [0.06–6.45] 0.71  Unknown 1.23 [0.16–9.18] 0.84 Comorbiditiesb  Achalasia 1.73 [0.52–5.72] 0.37  Anxiety 1.31 [0.46–3.70] 0.61 Prior foregut surgery 8.06 [2.29–28.39] 0.001

The multivariable logistic regression model adjusted for all variables listed in the table.

CI, confidence interval; HRM, high-resolution manometry.

aP value < 0.05 was considered significant.

bIrritable bowel syndrome, cognitive disorders, and other psychological disorders were not included in the multivariable regression analysis because there were 0 patients in the corresponding “not tolerated” subgroups.

As for comorbidities, there were 321 patients (6.29%) with anxiety, 12 (0.23%) with panic disorder, and 6 (0.12%) with other psychological disorders such as schizophrenia. For gastrointestinal-related comorbidities, 158 patients (3.09%) were previously diagnosed with achalasia and 105 (2.06%) with irritable bowel syndrome. Cognitive disorders including unspecified dementia, Alzheimer disease, and Parkinson disease were found in 12 patients (0.23%). No medical comorbidities were found to have a statistically significant effect on HRM tolerance in our study population because every patient in the irritable bowel syndrome, cognitive disorder, panic disorder, other psychological disorder subgroups tolerated HRM. However, prior foregut surgery had a significant effect on HRM tolerance because those with prior foregut surgeries had more than 8-fold increase in not tolerating HRM compared with those without previous foregut surgeries (OR 8.06, 95% CI 2.29–28.39; P = 0.001).

Among the 57 patients who did not tolerate HRM, nearly half (47.6%) had procedure reports that documented reasons for early termination of the procedure. Common reasons included excessive swallows during the study, discomfort after catheter placement, and inability to pass the catheter intranasally. Some documentations suggested associations with anatomical abnormalities. For example, catheters were not able to pass the upper esophageal sphincter in 2 patients with Zenker diverticulum. Three patients with hiatal hernias experienced coiling of catheters in the hernia, while the catheter could not pass through the tightened lower esophageal sphincter in 3 patients with a surgical history of Nissen fundoplication. Other cases were found to have increased esophageal edema (n = 2), esophageal web (n = 1), and distal esophageal diverticula (n = 1). After a failed manometry procedure, at least 21 patients (36.8%) underwent an endoscopic placement of the catheter, 3 (5.2%) proceeded with EndoFlip, and 28 (49.1%) did not follow-up or had another assessment that was documented in our network. Five patients (8.8%) repeated HRM, of whom 80% tolerated the procedure on the second attempt. No severe complications were documented (Table 4).

Table 4. - Outcomes of HRM procedure tolerance (N = 5,107) Outcomes n (%) Tolerated 5,050 (98.9) Not tolerated 57 (1.1)  Endoscopic placement 21  Repeat HRM 5  EndoFlip 3  No follow-up/attempt 28 Complications  Severe epistaxis 0  Sinusitis 0  Esophageal perforations 0  Cribriform plate injury 0  Intracranial placement 0  Pneumothorax 0

HRM, high-resolution manometry.

DISCUSSION

This is the first study to describe the tolerance of HRM procedures in a large patient population at a tertiary center. Among more than 5,000 patients, we found that approximately 98% of the patients tolerated the procedure well. Demographic factors such as sex, race, and ethnicity were not significantly associated with HRM tolerance. Other comorbidities of psychological, cognitive, and functional gastrointestinal disorders also did not have statistically significant impact on tolerability. However, age had a significant effect on tolerance of HRM, with further findings suggesting that children (aged younger than 18 years) and seniors (aged 80 years or older) were more likely to not tolerate the procedure compared with adults aged 18 to 79 years. The study also demonstrated an increase in HRM intolerance in those with prior esophageal or gastric surgery (P = 0.001). This is consistent with a 2011 study comprising 2,000 participants, which found incomplete esophageal pressure topography studies in 22 patients (9%) with a history of foregut surgery (13). In all, this study provides crucial data points for health economists for cost-benefit analyses, along with healthcare providers and patients to facilitate informed decision-making.

It is difficult to make definitive overall conclusions about the effect of age on tolerance of HRM due to the small sample size of children and seniors compared with that of the adult group in our study. However, the observed higher rates of termination in children and seniors compared with adults (aged 18–79 years) in our study may be explained by the effects of increased pain sensitivity in children (14) and age-related changes in oropharyngeal and esophageal swallowing in the elderly population (15). Studies have demonstrated clear differences in the availability of nociceptors and neuromediators between children and adults, resulting in higher sensitivity and longer duration of pain in children compared with that in adults (14). Based on our qualitative data, the placement of the catheter can cause discomfort and pain at any level from the entry of nares to the lower esophageal sphincter, which may not have been well tolerated by our pediatric patients. Second, presbyphagia and age-related loss of motor and neurosensory function with swallowing may be associated with decrease tolerance of HRM in the elderly population (16). Intranasal catheter placement for HRM requires simultaneous patient deglutition to prevent entry of the catheter into the trachea. Elderly patients develop age-related changes such as decrease in strength and amplitude of swallows, sarcopenia of the oropharyngeal structures, and prolonged reaction time with swallowing to cognitive stimuli (17,18). Thus, the elderly population may be less able to either perform synchronized swallows with catheter insertion or suppress excessive swallows during measurements, leading to early termination of the HRM study.

Although this is the first study to assess the tolerability and safety of HRM, many studies have investigated the patient safety of nasogastric tube (NGT) placements, which have some similarities in procedural techniques (19). Studies reported up to 1% of major complications such as pneumothorax or perforation in some multidisciplinary intensive care units (19,20). NGT placements are at a higher risk of major complications because placements mostly occur in inpatient settings for patients who are more likely to be noncooperative, cognitively impaired, or even unconscious. Misplacement of NGT insertions into the trachea and lungs can occur in up to 2% of cases, leading to serious complications including pleural effusions and pneumonitis (21). Due to events of significant harm or mortality from NGT insertion complications, there have been substantial efforts in the past decade to develop standardized protocols for insertion and confirmation (22). However, the results of our study suggest that we cannot use the safety profile of NGT placement for HRM. We believe HRM is a safer procedure because it is typically performed on conscious functional patients in outpatient settings, such that any discomfort or pain can be communicated to quickly halt further advancement of the catheter to avoid serious complications. Furthermore, insertion of the catheter is performed with a display of the real-time pressure measurement of the pharyngeal and esophageal contractions on the topography plots. The pharyngeal and upper esophageal contraction pressure pattern can be assessed by the healthcare professional during the insertion process to assure that the catheter is not advancing into the trachea and the pulmonary system. In this study of more than 5,000 HRM procedures, no case of visceral perforation was identified. Although the rate of perforation during HRM is unknown, we believe our data reflect the true lower complication rate of HRM when compared with NGT in clinical practice.

There are some limitations to this study. It is a single-center study at a tertiary academic institution with providers who are highly trained in manometry. All HRM procedures and catheter insertions were exclusively performed by experienced gastroenterologists at our institution. Although we do not believe the primary occupation of the proceduralist will affect the safety or tolerability of HRM, the intolerance rates may change based on the techniques and experience level of healthcare providers. On the contrary, more complex clinical cases are seen at a tertiary center with a diverse patient population, which could conversely increase intolerance rates. Another limitation is the lack of diversity in our population and small sample sizes of demographic and comorbidity subgroups. This may have been limiting in revealing significant relationships between demographic factors and intolerance of HRM. However, because the tolerability rate was markedly high, we believe that the overall conclusions of this study would not have changed.

In conclusion, HRM is safe and well-tolerated, with approximately 1 in every 100 patients not tolerating the procedure. Intolerance of HRM was more commonly seen in children and seniors compared with adults aged 18–79 years and was due to minor symptoms of discomfort without any serious complications. As the use of HRM in diagnosing esophageal motility disorders grows, there is a need to address intolerability risks with solutions such as implementing educational videos of a real subject undergoing manometry (23) or using medications such as oral viscous lidocaine. Future development of pediatric-sized HRM catheters can also be suggested, given nearly 40% of those who failed manometry required endoscopic interventions. Future studies should obtain more qualitative data to build on these ideas to improve HRM outcomes in population groups with higher risks of intolerance.

CONFLICTS OF INTEREST

Guarantors of the article: Janice E. Oh, MD, MSc, Ali Rezaie, MD, MSc.

Specific author contributions: J.E.O.: study concept and design; acquisition of data; analysis and interpretation of data; drafting of the manuscript; critical revision of the manuscript for important intellectual content; statistical analysis; and technical or material support. L.H.: acquisition of data; critical revision of the manuscript for important intellectual content. W.T.: acquisition of data; critical revision of the manuscript for important intellectual content. K.K.: acquisition of data; technical or material support. J.W.: analysis and interpretation of data; statistical analysis; technical or material support. E.K.: acquisition of data; technical or material support. S.-C.H.: acquisition of data; technical or material support. B.C.: acquisition of data; critical revision of the manuscript for important intellectual content. M.P.: acquisition of data; critical revision of the manuscript for important intellectual content. A.R.: study concept and design; acquisition of data; analysis and interpretation of data; critical revision of the manuscript for important intellectual content; technical or material support; and study supervision.

Financial support: None to report.

Potential competing interests: None to report.

IRB approval: This study was approved by the institutional review board of Cedars-Sinai Medical Center (Pro00034154).

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