Predicting Arterial Oxygen Desaturation Events Via Patient Journal and Pulse Oximetry Data in Postoperative Ambulatory Surgery Patients

Associations between patient and procedural factors on the nature and quality of the immediate in-home recovery from anesthesia following ambulatory orthopedic surgery are unknown. Further, there is a paucity of outcomes research quantitatively categorizing in-home patient recovery and safety following discharge from same-day orthopedic procedures. Tools are available, however, to shed light on outcomes in this population, and integration of such available measures is critical. Ambulatory orthopedic surgery is a burgeoning specialty, with growth expected over the foreseeable future. The expected increased patient caseload subsequent to implementation of the Affordable Care Act and aging Baby Boom generation suggests greater morbidity and mortality is on the horizon unless aggressive measures are taken at mitigating risk. Similarly, as the obesity epidemic expands, obesity-related comorbid conditions including obstructive sleep apnea (OSA) are likely to grow. The purpose of this research was to explore the relationship between ambulatory orthopedic patient-reported activities (quality of life metrics) and diagnostic factors (physical and perioperative care data) in the immediate postoperative period that are predictive of arterial oxygen desaturation. Data was obtained using a novel patient journal exploring sleep, pain, nausea, tobacco use, alcohol use, and appetite in conjunction with a valid and reliable portable, wrist-worn pulse oximeter. Additional assessment data was taken from the preanesthetic assessment. All participants were scored according to the STOP-Bang questionnaire, an accepted survey of OSA risk. Patients were recruited from a busy metropolitan ambulatory surgery center in Richmond, Virginia that sees approximately 500 cases monthly, and a 309-bed tertiary care hospital in West Burlington, Iowa. The target sample included 52 individual patients with data collected over the first two post-operative nights following discharge. Two patients were excluded. Negative binomial regression, log10 transformation, and least-squares regression examined the relationships the STOP-Bang questionnaire, quality of life data, and physical perioperative data had on postoperative desaturation events. Results suggested the STOP-Bang score predicted desaturation events and that age and BMI were significant individual predictors. Opiate pain medication treatment, a happy mood, and home CPAP use were associated with decreased events. This study provided a unique perspective in patient safety research, relating human behaviors and experiences with postoperative oxygen desaturation. Future research projects aligned with postoperative monitoring, pulse oximetry, patient safety, and obstructive sleep apnea are potential following the findings of this study

Breathing Rate Estimation From the Electrocardiogram and Photoplethysmogram: A Review.

Breathing rate (BR) is a key physiological parameter used in a range of clinical settings. Despite its diagnostic and prognostic value, it is still widely measured by counting breaths manually. A plethora of algorithms have been proposed to estimate BR from the electrocardiogram (ECG) and pulse oximetry (photoplethysmogram, PPG) signals. These BR algorithms provide opportunity for automated, electronic, and unobtrusive measurement of BR in both healthcare and fitness monitoring. This paper presents a review of the literature on BR estimation from the ECG and PPG. First, the structure of BR algorithms and the mathematical techniques used at each stage are described. Second, the experimental methodologies that have been used to assess the performance of BR algorithms are reviewed, and a methodological framework for the assessment of BR algorithms is presented. Third, we outline the most pressing directions for future research, including the steps required to use BR algorithms in wearable sensors, remote video monitoring, and clinical practice

Étude des altérations du contrôle cardiorespiratoire chez des modèles ovins de pathologies néonatales

Introduction : L'implication des RGO dans les événements cardiorespiratoires des prématurés reste controversée. Bien que quelques études réalisées sur des animaux nouveau-nés à terme ou adultes aient montré que la stimulation des récepteurs œsophagiens entraine des réflexes cardiorespiratoires inhibiteurs, l’impact d’une naissance prématurée sur ces derniers demeure inconnu. L’article 1 vise à tester l’hypothèse selon laquelle la naissance prématurée augmente l'inhibition cardiorespiratoire lors d’une stimulation oesophagienne. Le sepsis néonatal est à l’origine d’une mortalité substantielle, en partie en raison de ses conséquences sur le contrôle cardiorespiratoire. Les réponses au sepsis néonatal sont variables et peuvent expliquer un faible diagnostic pendant la phase initiale de l'infection. L'implication du sepsis néonatal sur le contrôle cardiorespiratoire reste mal connue. L’article 2 vise à comprendre davantage le lien entre l’inflammation accompagnant un sepsis néonatal et les altérations cardiaques et respiratoires. Méthodes : Article 1. Huit agneaux nés à terme et dix agneaux nés 14 jours prématurément ont été étudiés. Une polysomnographie a été réalisée pour suivre en continu l’ECG, la respiration, la pression artérielle systémique, les stades de conscience et la saturation en O2. Cinq stimulations de l'œsophage supérieur et/ou inférieur, incluant l'inflation rapide par ballonnet et/ou l'injection d’HCl, ont été effectuées dans un ordre aléatoire. Article 2. Deux polysomnographies de six heures ont été réalisées sur deux jours consécutifs chez huit agneaux. La première a été effectuée suivant une injection IV de solution saline, et la deuxième après une injection IV de 2,5 μg/kg de lipopolysaccharides (LPS). La température, les gaz du sang artériel, les stades de conscience, l'activité locomotrice, les fréquences respiratoire et cardiaque (FR et FC), la variabilité cardiaque et respiratoire (VFC et VFR), la pression artérielle systémique, les apnées et les ralentissements cardiaques ont été évalués. Résultats : Les stimulations œsophagiennes induisent des réflexes cardiorespiratoires inhibiteurs (apnées, bradycardies, désaturations en oxygène) qui sont amplifiés par la naissance prématurée. L'inhibition cardiorespiratoire la plus importante est observée suite à une stimulation simultanée de l'œsophage inférieur et supérieur. L’injection de LPS induit des altérations cliniques (augmentation biphasique de la température et diminution de la mobilité et de l’éveil agité) et cardiorespiratoires (augmentation de la FR et de la FC et diminution de la VFC et de la VFR) en plus d’une inflammation du tronc cérébral. Conclusion : La stimulation œsophagienne entraine une augmentation des événements cardiorespiratoires chez les agneaux prématurés, probablement en raison de l'immaturité globale du système nerveux. L'injection de LPS entraine une inflammation systémique mimant un sepsis bactérien chez les agneaux avec de multiples conséquences, y compris des altérations cardiorespiratoires

Clinical investigation of plethysmographic variability index: A derivative index of pulse oximetry in anesthetized dogs

Plethysmographic Variability Index (PVI) is a derivative index of pulse oximetry that allows evaluating an individual\u27s intravascular volume status. Perfusion Index (PI) represents the strength of pulse signal at the anatomic site of measurement from which PVI is calculated using changes in PI over respiratory cycles. Plethysmographic Variability Index has been used to detect hypovolemia and predict fluid responsiveness in mechanically ventilated human patients however, fewer studies are available in spontaneously breathing patients. The use of PVI has not been explored extensively in dogs so far. The goals of this study were to establish a common range for PVI and assess relationship of the PVI, PI and various clinical variables in the anesthetized spontaneously breathing dogs. Values of PVI and PI derived from Masimo pulse oximetry were obtained at 5, 10, 15 and 20 minutes after anesthetic induction but before surgical stimulation together with cardiorespiratory variables that included heart rate, blood pressures (systolic, mean and diastolic blood pressures), respiratory rate and hemoglobin saturation of oxygen (SpO2) in 73 dogs with ASA 1-3 status admitted to the Purdue Teaching Hospital.^ Other clinical variables like body temperature, anesthetic protocol used, pre-induction packed cell volume (PCV) and total protein (TP) values, recumbency positions (sternal, lateral or dorsal recumbency) and rate of crystalloid fluids administration (5 vs 10 ml/kg/hr) were also obtained. Data were analysed using non-parametric Spearman\u27s rho coefficient and Kruskal Wallis one-way ANOVA by ranks to assess temporal relationship of PVI with all the clinical variables and with significant level set at P\u3c0.05. A common range of PVI was 5-43% with a median 18%. There was no significant correlation found between PVI and PI. Plethysmographic Variability Index positively correlated with the systolic blood pressure (rs=0.25; P\u3c0.001), mean blood pressure (rs=0.26; P\u3c0.001), diastolic blood pressure (rs=0.36; P\u3c0.001) and body temperature (rs=0.166; P=0.004). The other cardiorespiratory variables, recumbency positions, rate of crystalloid fluid administration, pre-operative PCV and TP values had no relationship with PVI. Premedication containing dexmedetomidine resulted in higher PVI (Kruskal-Wallis Test; P=0.001) and lower PI values (Kruskal-Wallis Test; P=0.004) and the opposite was true with protocols that contained acepromazine. It was concluded that while evaluating PVI for fluid response in the anesthetized dogs, various clinical factors should be taken into consideration