Definitions and Measurements for Atypical Presentations at Risk for Diagnostic Errors in Internal Medicine: Protocol for a Scoping Review.

BACKGROUND: Atypical presentations have been increasingly recognized as a significant contributing factor to diagnostic errors in internal medicine. However, research to address associations between atypical presentations and diagnostic errors has not been evaluated due to the lack of widely applicable definitions and criteria for what is considered an atypical presentation. OBJECTIVE: The aim of the study is to describe how atypical presentations are defined and measured in studies of diagnostic errors in internal medicine and use this new information to develop new criteria to identify atypical presentations at high risk for diagnostic errors. METHODS: This study will follow an established framework for conducting scoping reviews. Inclusion criteria are developed according to the participants, concept, and context framework. This review will consider studies that fulfill all of the following criteria: include adult patients (participants); explore the association between atypical presentations and diagnostic errors using any definition, criteria, or measurement to identify atypical presentations and diagnostic errors (concept); and focus on internal medicine (context). Regarding the type of sources, this scoping review will consider quantitative, qualitative, and mixed methods study designs; systematic reviews; and opinion papers for inclusion. Case reports, case series, and conference abstracts will be excluded. The data will be extracted through MEDLINE, Web of Science, CINAHL, Embase, Cochrane Library, and Google Scholar searches. No limits will be applied to language, and papers indexed from database inception to December 31, 2023, will be included. Two independent reviewers (YH and RK) will conduct study selection and data extraction. The data extracted will include specific details about the patient characteristics (eg, age, sex, and disease), the definitions and measuring methods for atypical presentations and diagnostic errors, clinical settings (eg, department and outpatient or inpatient), type of evidence source, and the association between atypical presentations and diagnostic errors relevant to the review question. The extracted data will be presented in tabular format with descriptive statistics, allowing us to identify the key components or types of atypical presentations and develop new criteria to identify atypical presentations for future studies of diagnostic errors. Developing the new criteria will follow guidance for a basic qualitative content analysis with an inductive approach. RESULTS: As of January 2024, a literature search through multiple databases is ongoing. We will complete this study by December 2024. CONCLUSIONS: This scoping review aims to provide rigorous evidence to develop new criteria to identify atypical presentations at high risk for diagnostic errors in internal medicine. Such criteria could facilitate the development of a comprehensive conceptual model to understand the associations between atypical presentations and diagnostic errors in internal medicine. TRIAL REGISTRATION: Open Science Framework; www.osf.io/27d5m. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/56933.

Measurement accuracy of a microwave doppler sensor beneath the mattress as a continuous respiratory rate monitor: a method comparison study.

PURPOSE: Non-contact continuous respiratory rate monitoring is preferred for early detection of patient deterioration. However, this technique is under development; a gold standard respiratory monitor has not been established. Therefore, this prospective observational method comparison study aimed to compare the measurement accuracy of a non-contact continuous respiratory rate monitor, a microwave Doppler sensor positioned beneath the mattress, with that of other monitors. METHODS: The respiratory rate of intensive care unit patients was simultaneously measured using a microwave Doppler sensor, capnography, thoracic impedance pneumography, and a piezoelectric sensor beneath the mattress. Bias and 95% limits of agreement between the respiratory rate measured using capnography (standard reference) and that measured using the other three methods were calculated using Bland-Altman analysis for repeated measures. Clarke error grid (CEG) analysis evaluated the sensor's ability to assist in correct clinical decision-making. RESULTS: Eighteen participants were included, and 2,307 data points were analyzed. The bias values (95% limits of agreement) of the microwave Doppler sensor, thoracic impedance pneumography, and piezoelectric sensor were 0.2 (- 4.8 to 5.2), 1.5 (- 4.4 to 7.4), and 0.4 (- 4.0 to 4.8) breaths per minute, respectively. Clinical decisions evaluated using CEG analyses were correct 98.1% of the time for the microwave Doppler sensor, which was similar to the performance of the other devices. CONCLUSION: The microwave Doppler sensor had a small bias but relatively low precision, similar to other devices. In CEG analyses, the risk of each monitor leading to inadequate clinical decision-making was low. TRIAL REGISTRATION NUMBER: UMIN000038900, February 1, 2020.

Effects of Combinational Use of Additional Differential Diagnostic Generators on the Diagnostic Accuracy of the Differential Diagnosis List Developed by an Artificial Intelligence-Driven Automated History-Taking System: Pilot Cross-Sectional Study.

BACKGROUND: Low diagnostic accuracy is a major concern in automated medical history-taking systems with differential diagnosis (DDx) generators. Extending the concept of collective intelligence to the field of DDx generators such that the accuracy of judgment becomes higher when accepting an integrated diagnosis list from multiple people than when accepting a diagnosis list from a single person may be a possible solution. OBJECTIVE: The purpose of this study is to assess whether the combined use of several DDx generators improves the diagnostic accuracy of DDx lists. METHODS: We used medical history data and the top 10 DDx lists (index DDx lists) generated by an artificial intelligence (AI)-driven automated medical history-taking system from 103 patients with confirmed diagnoses. Two research physicians independently created the other top 10 DDx lists (second and third DDx lists) per case by imputing key information into the other 2 DDx generators based on the medical history generated by the automated medical history-taking system without reading the index lists generated by the automated medical history-taking system. We used the McNemar test to assess the improvement in diagnostic accuracy from the index DDx lists to the three types of combined DDx lists: (1) simply combining DDx lists from the index, second, and third lists; (2) creating a new top 10 DDx list using a 1/n weighting rule; and (3) creating new lists with only shared diagnoses among DDx lists from the index, second, and third lists. We treated the data generated by 2 research physicians from the same patient as independent cases. Therefore, the number of cases included in analyses in the case using 2 additional lists was 206 (103 cases × 2 physicians' input). RESULTS: The diagnostic accuracy of the index lists was 46% (47/103). Diagnostic accuracy was improved by simply combining the other 2 DDx lists (133/206, 65%, P<.001), whereas the other 2 combined DDx lists did not improve the diagnostic accuracy of the DDx lists (106/206, 52%, P=.05 in the collective list with the 1/n weighting rule and 29/206, 14%, P<.001 in the only shared diagnoses among the 3 DDx lists). CONCLUSIONS: Simply adding each of the top 10 DDx lists from additional DDx generators increased the diagnostic accuracy of the DDx list by approximately 20%, suggesting that the combinational use of DDx generators early in the diagnostic process is beneficial.

Stomach position evaluated using computed tomography is related to successful post-pyloric enteral feeding tube placement in critically ill patients: a retrospective observational study.

BACKGROUND: Post-pyloric enteral feeding reduces respiratory complications and shortens the duration of mechanical ventilation. Blind placement of post-pyloric enteral feeding tubes (EFT) in patients with critical illnesses is often the first-line method because endoscopy or fluoroscopy cannot be easily performed at bedside; however, difficult placements regularly occur. We reported an association between the stomach position caudal to spinal level L1-L2, evaluated by abdominal radiographs after placement, and difficult placement; however, this method could not indicate difficulty before EFT placement. The aim of our study was to evaluate the association between stomach position, estimated using computed tomography (CT) images taken before the blind placement of the post-pyloric EFT, and the difficulty of EFT placement. METHODS: Data from patients aged ≥ 20 years who underwent post-pyloric EFT in our intensive care unit were obtained retrospectively. Logistic regression analysis was used to evaluate the association between successful initial EFT placement and explanatory variables, including stomach position estimated by CT. Two cut-off values were used: caudal to L1-L2 based on a previous study and the best cut-off value calculated by the receiver operating characteristic curve. Variable selection was performed backward stepwise using Akaike's Information Criterion. RESULTS: Of the total of 453 patients who were enrolled, the success rate of the initial EFT placement was 43.5%. The adjusted odds ratio for successful initial EFT placement of the stomach position caudal to L1-L2 was 0.61 (95% confidence interval: 0.41-1.07). Logistic regression analysis, including the stomach position caudal to L2-L3, calculated as the best cut-off value, indicated that stomach position was an independent factor for failure of initial EFT placement (adjusted odds ratio, 0.55; 95% confidence interval: 0.33-0.91). CONCLUSIONS: Stomach position evaluated using CT images was associated with successful initial post-pyloric EFT placement. The best cut-off value of the greater curvature of the stomach to predict the success or failure of the first attempt was spinal level L2-L3. Trial registration University Hospital Medical Information Network Clinical Trials Registry (UMIN000046986; February 28, 2022). https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000052151.

Survey of Inpatient Consultations with General Internal Medicine Physicians in a Tertiary Hospital: A Retrospective Observational Study.

Purpose: The general internal medicine (GIM) department can be an effective diagnostic coordinator for undiagnosed outpatients. We investigated the contribution of GIM consultations to the diagnosis of patients admitted to specialty departments in hospitals in Japan that have not yet adopted a hospitalist system. Patients and Methods: This single-center, retrospective observational study was conducted at a university hospital in Japan. GIM consultations from other departments on inpatients aged ≥20 years, from April 2016 to March 2021, were included. Data were extracted from electronic medical records, and consultation purposes were categorized into diagnosis, treatment, and diagnosis and treatment. The primary outcome was new diagnosis during hospitalization for patients with consultation purpose of diagnosis or diagnosis and treatment. The secondary outcomes were the purposes of consultation with the Diagnostic and Generalist Medicine department. Results: In total, 342 patients were included in the analysis. The purpose of the consultations was diagnosis for 253 patients (74%), treatment for 60 (17.5%), and diagnosis and treatment for 29 patients (8.5%). In 282 consultations for diagnosis and diagnosis and treatment, 179 new diagnoses were established for 162 patients (57.5%, 95% confidence interval [CI], 51.5-63.3). Conclusion: The GIM department can function as a diagnostic consultant for inpatients with diagnostic problems admitted to other specialty departments in hospitals where hospitalist or other similar systems are not adopted.

The utility of phonocardiograms in real-time remote cardiac auscultation using an internet-connected electronic stethoscope: Open-label randomized controlled pilot trial.

Background: We have shown classical cardiac auscultation was superior to remote auscultation. We developed a phonocardiogram system to visualize sounds in remote auscultation. Objective: This study aimed to evaluate the effect of phonocardiograms on the diagnostic accuracy in remote auscultation using a cardiology patient simulator. Methods: In this open-label randomized controlled pilot trial, we randomly assigned physicians to the real-time remote auscultation group (control group) or the real-time remote auscultation with the phonocardiogram group (intervention group). Participants attended a training session in which they auscultated 15 sounds with the correct classification. After that, participants attended a test session where they had to classify 10 sounds. The control group auscultated the sounds remotely using an electronic stethoscope, an online medical program and a 4-K TV speaker without watching the TV screen. The intervention group performed auscultation like the control group but watched the phonocardiogram on the TV screen. The primary and secondary outcomes were the total test scores and each sound score, respectively. Results: A total of 24 participants were included. The total test score in the intervention group (80/120, 66.7%) was higher than that in the control group (66/120, 55.0%), although the difference was statistically insignificant (P = .06). The correct answer rates of each sound were not different. Valvular/irregular rhythm sounds were not misclassified as normal sounds in the intervention group. Conclusions: Using a phonocardiogram improved the total correct answer rate by more than 10% in remote auscultation, although statistically insignificant. The phonocardiogram could help physicians screen valvular/irregular rhythm sounds from normal sounds. Trial registration: UMIN-CTR UMIN000045271; https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000051710.

Acute-on-Chronic Pattern of Isolated Upper Back Pain in a Patient With Acute Coronary Syndrome.

The aim of this case report is to describe the diagnostic pitfalls of acute coronary syndrome in patients with relatively atypical presentation and how we can prevent diagnostic errors in such a patient, particularly focusing on occupational information. A 66-year-old male, a professional taxi driver, presented with severely deteriorated chronic upper back pain on the left side. Furthermore, the upper back pain was exacerbated by changes in position. An orthopedist examined the patient and arrived at a provisional diagnosis of musculoskeletal pain. However, as the patient was concerned about his cardiopulmonary diseases, he visited another physician. Although musculoskeletal pain was still considered as the most possible diagnosis, the physician advised him additional tests for cardiovascular diseases because he had some risk factors such as smoking, hypertension, and dyslipidemia, and the physician thought that "taxi driving" was a high-risk occupation for cardiovascular diseases. Finally, the patient was diagnosed with acute coronary syndrome, and the pain abated soon after percutaneous coronary intervention. Musculoskeletal pain is very common in professional drivers, and isolated upper back pain worsened by changes in position is a characteristic of musculoskeletal disease. However, since professional drivers also have a higher risk of cardiovascular diseases, physicians should consider the coexistence of two types of conditions. This case underscores that if physicians could utilize occupational information to assess patients' risks, diagnostic accuracy would improve, particularly in patients presenting with atypical symptoms and signs, which are at risk of diagnostic errors.

Diagnostic Accuracy of Differential-Diagnosis Lists Generated by Generative Pretrained Transformer 3 Chatbot for Clinical Vignettes with Common Chief Complaints: A Pilot Study.

The diagnostic accuracy of differential diagnoses generated by artificial intelligence (AI) chatbots, including the generative pretrained transformer 3 (GPT-3) chatbot (ChatGPT-3) is unknown. This study evaluated the accuracy of differential-diagnosis lists generated by ChatGPT-3 for clinical vignettes with common chief complaints. General internal medicine physicians created clinical cases, correct diagnoses, and five differential diagnoses for ten common chief complaints. The rate of correct diagnosis by ChatGPT-3 within the ten differential-diagnosis lists was 28/30 (93.3%). The rate of correct diagnosis by physicians was still superior to that by ChatGPT-3 within the five differential-diagnosis lists (98.3% vs. 83.3%, p = 0.03). The rate of correct diagnosis by physicians was also superior to that by ChatGPT-3 in the top diagnosis (53.3% vs. 93.3%, p < 0.001). The rate of consistent differential diagnoses among physicians within the ten differential-diagnosis lists generated by ChatGPT-3 was 62/88 (70.5%). In summary, this study demonstrates the high diagnostic accuracy of differential-diagnosis lists generated by ChatGPT-3 for clinical cases with common chief complaints. This suggests that AI chatbots such as ChatGPT-3 can generate a well-differentiated diagnosis list for common chief complaints. However, the order of these lists can be improved in the future.

Creatinine Reduction Ratio Is a Prognostic Factor for Acute Kidney Injury following Cardiac Surgery with Cardiopulmonary Bypass: A Single-Center Retrospective Cohort Study.

Acute kidney injury (AKI) after cardiac surgery is a common complication that can lead to death. We previously reported that the creatinine reduction ratio (CRR) serves as a useful prognostic factor for AKI. The primary objective of this study was to determine the predictors of AKI after surgery. The secondary objective was to determine the reliability of the CRR for short- and long-term outcomes. We retrospectively collected information about cardiac surgery patients who underwent cardiopulmonary bypass. Patients were divided into AKI and non-AKI groups based on the AKIN and RIFLE criteria. We analyzed the two groups regarding the preoperative patient data and operative information. The CRR was calculated as follows: (preoperative creatinine-postoperative creatinine)/preoperative creatinine. The prognostic factors of AKI-CS were surgery time, CPB time, aorta clamp time, platelet transfusion, and CRR < 20%. In the multivariate logistical analysis, CRR was an independent predictor of AKI (adjusted odds ratio: 0.90 [0.87-0.93], p < 0.001). However, there were no significant differences in CRR in terms of the rate of new onset chronic kidney disease (CKD). After cardiac surgery with cardiopulmonary bypass, CRR has good diagnostic power for predicting perioperative AKI. However, we cannot use it as a prognostic factor over a long-term period.

Outcomes of General Internal Medicine Consultations for Diagnosis from Specialists in a Tertiary Hospital: A Retrospective Observational Study.

Purpose: The data on the diagnostic contribution of general internal medicine (GIM) consultations for undiagnosed health problems from specialists are scarce. This study aims to explore the role of generalists as diagnostic medicine consultants in tertiary care settings. Patients and Methods: We conducted a retrospective observational study at a Japanese university hospital. GIM consultations for diagnosis from other departments on outpatients aged ≧ 20 years from January 2018 to December 2020 were included. Data were extracted from electronic medical records. The primary outcome was new diagnosis rates. The secondary outcomes were new diagnosis rates with clinical significance and clinical outcomes at 90 days from the index visit. Results: A total of 328 patients were included. The top five consulting departments were orthopedics (17.0%), cardiovascular (10.3%), otorhinolaryngology (8.8%), neurology (8.8%), and gastroenterology (7.9%). GIM identified 456 chief complaints (CCs), and the top five were fever (10.9%), abnormal laboratory results (8.3%), fatigue (5.9%), and pain (7.4%) or numbness (4.6%) in the extremities. There were 139 (104/328 patients: 31.8%) specialty consultations from GIM, and the top five departments were rheumatology (21.1%), gastroenterology (19.2%), orthopedics (9.6%), psychiatry (9.6%), and neurology (9.6%). In total, 277 new diagnoses were established in 232 patients (70.7%), and 203 patients had new diagnoses with clinical significance (61.8%). Clinical outcomes at 90 days from the time of the index visit were resolution/improvement (60.7%), unchanged/worsened (22.3%), and unknown (17.0%). Conclusion: Over 70% of GIM consultations from other departments established new diagnoses with favorable outcomes in >60% of the patients.

Hypotension after general anesthesia induction using remimazolam in geriatric patients: Protocol for a double-blind randomized controlled trial.

INTRODUCTION: In geriatric patients, hypotension is often reported after general anesthesia induction using propofol. Remimazolam is a novel short-acting sedative. However, the incidence of hypotension after general anesthesia induction using remimazolam in geriatric patients remains unclear. This study aims to compare the incidence of hypotension associated with remimazolam and propofol in patients aged ≥80 years. METHODS: This single-center, double-blind, randomized, two-arm parallel group, standard treatment-controlled, interventional clinical trial will include 90 patients aged ≥80 years undergoing elective surgery under general anesthesia who will be randomized to receive remimazolam or propofol for induction. The primary outcome is the incidence of hypotension after general anesthesia induction, occurring between the start of drug administration and 3 min after intubation. We define hypotension as mean blood pressure <65 mmHg. The primary outcome will be analyzed using the full analysis set. The incidence of hypotension in the two groups will be compared using the Mantel-Haenszel χ2 test. Subgroup analysis of the primary outcome will be performed based on the Charlson comorbidity index, clinical frailty scale, hypertension in the ward, and age. Secondary outcomes will be analyzed using the Fisher's exact test, Student's t test, and Mann-Whitney U test, as appropriate. Logistic regression analysis will be performed to explore the factors associated with the incidence of hypotension after anesthesia induction. DISCUSSION: Our trial will determine the efficacy of remimazolam in preventing hypotension and provide evidence on the usefulness of remimazolam for ensuring hemodynamic stability during general anesthesia induction in geriatric patients. TRIAL REGISTRATION: The study has been registered with UMIN Clinical Trials Registry (UMIN000042587), on June 30, 2021.

An autopsy case of pulmonary arterial hypertension in an elderly patient with multimorbidity: a case report.

BACKGROUND: There is an increasing number of elderly patients with pulmonary arterial hypertension (PAH), and their characteristics differ from those of young or middle-aged patients with this condition. CASE SUMMARY: A 73-year-old woman with a history of myocardial infarction and cardiovascular risk factors was admitted to the hospital with 2-week exertional dyspnoea. Her initial diagnosis was heart failure with preserved ejection fraction, but the symptoms persisted despite receiving treatment with diuretics. Additional tests showed a significant decrease in diffusing capacity of carbon monoxide and findings suggestive of severe pulmonary hypertension (PH). Contrast-enhanced computed tomography of the chest, and pulmonary angiography, showed no narrowing or obstruction of the pulmonary arteries. Right heart catheterization revealed haemodynamic data implying pre-capillary PH. Her condition gradually deteriorated to World Health Organization functional class IV, and sequential combination therapy with tadalafil, macitentan, and selexipag was initiated with a PAH diagnosis; however, she died 1 month later. Pathological findings in autopsy were consistent with PAH, and some parts of the lungs revealed the presence of obstructive and interstitial lung disease. DISCUSSION: The majority of elderly patients with PAH might have multimorbidity. However, there is no specific treatment strategy. It is associated with diagnostic delay and worse prognosis; therefore, early suspicion and comprehensive tests, including right heart catheterization, are essential for better management.

Evaluation of respiratory rate monitoring using a microwave Doppler sensor mounted on the ceiling of an intensive care unit: a prospective observational study.

Continuous monitoring of the respiratory rate is crucial in an acute care setting. Contact respiratory monitoring modalities such as capnography and thoracic impedance pneumography are prone to artifacts, causing false alarms. Moreover, their cables can restrict patient behavior or interrupt patient care. A microwave Doppler sensor is a novel non-contact continuous respiratory rate monitor. We compared respiratory rate measurements performed with a microwave Doppler sensor mounted on the ceiling of an intensive care unit with those obtained by conventional methods in conscious and spontaneously breathing patients. Participants' respiratory rate was simultaneously measured by visual counting of chest wall movements for 60 s; a microwave Doppler sensor; capnography, using an oxygen mask; and thoracic impedance pneumography, using electrocardiogram electrodes. Bland-Altman analysis for repeated measures was performed to calculate bias and 95% limits of agreement between the respiratory rate measured by visual counting (reference) and that measured by each of the other methods. Among 52 participants, there were 336 (microwave Doppler sensor), 275 (capnography), and 336 (thoracic impedance pneumography) paired respiratory rate data points. Bias (95% limits of agreement) estimates were as follows: microwave Doppler sensor, 0.3 (- 6.1 to 6.8) breaths per minute (bpm); capnography, - 1.3 (- 8.6 to 6.0) bpm; and thoracic impedance pneumography, 0.1 (- 4.4 to 4.7) bpm. Compared to visual counting, the microwave Doppler sensor showed small bias; however, the limits of agreement were similar to those observed in other conventional methods. Our monitor and the conventional ones are not interchangeable with visual counting.Trial registration number: UMIN000032021, March/30/2018.

Multivariate analysis of factors associated with first-pass success in blind placement of a post-pyloric feeding tube: a retrospective study.

BACKGROUND: Trans-jejunal nutrition via a post-pyloric enteral feeding tube has a low risk of aspiration or reflux; however, placement of the tube using the blind method can be difficult. Assistive devices, such as fluoroscopy or endoscopy, are useful but may not be suitable for patients with hemodynamic instability or severe respiratory failure. The aim of this study was to explore factors associated with first-pass success in the blind placement of post-pyloric enteral feeding tubes in critically ill patients. METHODS: Data were obtained retrospectively from the medical records of adult patients who had a post-pyloric enteral feeding tube placed in the intensive care unit between January 1, 2012, and December 31, 2018. Logistic regression analysis was performed to assess the association between first-pass success and the independent variables. For logistic regression analysis, the following 13 variables were defined as independent variables: age, sex, height, fluid balance from baseline, use of sedatives, body position during the procedure, use of cardiac assist devices, use of prokinetic agents, presence or absence of intestinal peristalsis, postoperative cardiovascular surgery, use of renal replacement therapy, serum albumin levels, and position of the greater curvature of the stomach in relation to spinal levels L1 - L2. RESULTS: Data obtained from 442 patients were analyzed. The first-pass success rate was 42.8% (n = 189). Logistic regression analysis demonstrated that the position of the greater curvature of the stomach cephalad to L1 - L2 was only associated with successful placement (odds ratio for first-pass success, 0.62; 95% confidence interval: 0.40 - 0.95). CONCLUSIONS: In critically ill patients, the position of the greater curvature of the stomach caudal to L1 - L2 may be associated with a lower first-pass success rate of the blind method for post-pyloric enteral feeding tube placement. Further studies are needed to verify our results because the position of the stomach was estimated by radiographs after enteral feeding tube placement. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry (UMIN000036549; April 20, 2019).

A question is "what are the optimal targets for anticoagulant therapies?"

A high mortality rate is found among septic patients with disseminated intravascular coagulation (DIC). Anticoagulants have been used for treating septic DIC especially in Japanese clinical settings; however, their effectiveness is quite controversial across studies. According to several randomized controlled trials and meta-analyses, antithrombin and recombinant thrombomodulin had no therapeutic benefit in the treatment of sepsis. However, the majority of the previous research did not discuss "septic DIC" but simply "sepsis", and some reviews showed that anticoagulants were benefit only in septic DIC. Although immunothrombosis plays an important role in early host defense, it can lead to DIC and organ failure if dysregulated. Therefore, we advocate anticoagulant therapies might have beneficial effects, but research on optimal patient selection is currently lacking.

The perfusion index measured by the pulse oximeter affects the agreement between ClearSight and the arterial catheter-based blood pressures: A prospective observational study.

BACKGROUND: ClearSight is a noninvasive arterial blood pressure monitor, but it remains unknown whether it is affected by the state of perfusion to the fingers. We investigated whether the lower perfusion index (PI) measured with a pulse oximeter, which reflects finger perfusion, would affect the agreement between arterial pressures measured with ClearSight versus those obtained with an arterial catheter. METHODS: Paired arterial pressure data (ClearSight and arterial catheter-based pressures) and PI values were prospectively obtained from 30 patients undergoing major abdominal surgery. The primary outcome was standard deviation (SD) of the bias (precision) of blood pressure between ClearSight and arterial catheter. The ratio of the adjusted SD of the bias between PI≤1 and PI>1 was calculated using the linear mixed-effects model. The secondary outcomes were the bias and the limits of agreement (LOA) between the two devices (repeated measures Bland-Altman analysis). RESULTS: We analyzed 6312 paired data points. The adjusted SD of bias in PI ≤1 compared with those in PI >1 was 1.4-fold (95% confidence interval: 1.3- to 1.4-fold) for systolic arterial pressure, 1.5-fold (95% confidence interval: 1.3- to 1.6-fold) for diastolic arterial pressure, and 1.3-fold (95% confidence interval: 1.2- to 1.5-fold) for mean arterial pressure. The bias (LOA) were as follows: systolic arterial pressure in the PI ≤1 and PI >1 groups, -3.5 (-35.4 to 28.4) mmHg and 2.2 (-19.9 to 24.3) mmHg, respectively; diastolic arterial pressure in the PI ≤1 and PI >1 groups, 13.1 (-5.1 to 31.3) mmHg and 9.0, (-2.6 to 20.6) mmHg, respectively; and mean arterial pressure in the PI ≤1 and PI >1 groups, 8.7 (-11.3 to 28.7) mmHg and 7.6 (-6.2 to 21.3) mmHg, respectively. CONCLUSIONS: PI ≤1 was associated with a large SD of the bias between the devices. The PI value could be a real-time indicator of ClearSight precision.