A comparison of the temperature difference according to the placement of a nasopharyngeal temperature probe

Evaluation of pulse oximeter at the nasal septum during general anesthesia: comparison with finger oximeter

PURPOSE

Though the finger is generally recommended for pulse oxygen saturation (SpO2) monitoring site, its reliability may be compromised in conditions of poor peripheral perfusion. Therefore, we compared the performance of nasal septum SpO2 monitoring with finger SpO2 monitoring relative to simultaneous arterial oxygen saturation (SaO2) monitoring in generally anesthetized patients.

METHODS

In 23 adult patients, comparisons of SpO2 measured at the nasal septum and finger with simultaneous SaO2 were made at four time points during the 90 min study period. A pulse oximetry monitoring failure was defined as a > 10 s continuous failure of in an adequate SpO2 data acquisition. Core temperature as well as finger-tip and nasal septum temperatures were simultaneously measured at 10 min intervals.

RESULTS

A total of 92 sets of SpO2 and SaO2 measurements were obtained in 23 patients. The bias and precision for SpO2 measured at the nasal septum were - 0.8 ± 1.3 (95% confidence interval: - 1.1 to - 0.6), which was similar to those for SpO2 measured at the finger (- 0.6 ± 1.4; 95% confidence interval: - 0.9 to - 0.4) (p = 0.154). Finger-tip temperatures were consistently lower than other two temperatures at all time points (p < 0.05), reaching 33.5 ± 2.3 °C at 90 min after induction of anesthesia. While pulse oximetry monitoring failure did not occur for nasal septum probe, two cases of failure occurred for finger probe.

CONCLUSIONS

Considering the higher stability to hypothermia with a similar accuracy, nasal septum pulse oximetry may be an attractive alternative to finger pulse oximetry. Trail registration This study was registered with Clinical Research Information Service (CRIS: https://cris.nih.go.kr/cris/en/ ; ref: KCT0008352).

Optimal Positioning of Nasopharyngeal Temperature Probes in Infants and Children: A Prospective Cohort Study

BACKGROUND

The nasopharynx is an easily accessible core-temperature monitoring site, but insufficient or excessive nasopharyngeal probe insertion can underestimate core temperature. Our goal was to estimate optimal nasopharyngeal probe insertion depth as a function of age.

METHODS

We enrolled 157 pediatric patients who had noncardiac surgery with endotracheal intubation in 5 groups: (1) newborn to 6 months old, (2) infants 7 months to 1 year old, (3) children 13 to 23 months old, (4) children 2 to 5 years old, and (5) children 6 to 12 years old. A reference esophageal temperature probe was inserted at an appropriate depth based on each patient's height. A nasopharyngeal temperature probe was inserted from the naris at 10 cm in newborn and infants, 15 cm in children aged 1 to 5 years old, and 20 cm in children who were 6 years or older. The study nasopharyngeal probes were withdrawn 1, 2.5, or 2 cm (depending on age) 10 times at 5-minute intervals. Optimal probe insertion distances were defined by limits of agreement (LOAs) between nasopharyngeal and esophageal temperatures <0.5 °C.

RESULTS

Optimal nasopharyngeal temperature probe position ranged from 6 to 10 cm in infants up to 6 months old, 7 to 8 cm in infants 7 to 12 months old, 7.5 to 12 cm in children 13 to 23 months old, and 10 to 12 cm in children aged 6 years and older. The 95% LOAs were <0.5 °C for all age categories except the 2- to 5-year-old group where the limits extended from -0.67 °C to 0.52 °C at 9 cm. At the optimal position within each age range, the bias (average nasopharyngeal-to-esophageal temperature difference) was ≤0.1 °C.

CONCLUSIONS

Nasopharyngeal thermometers accurately measure core temperature, but only when probes are inserted a proper distance, which varies with age. As with much in pediatrics, nasopharyngeal thermometer insertion depths should be age appropriate.

Neuroprotective effect of selective hypothermic cerebral perfusion in extracorporeal cardiopulmonary resuscitation: A preclinical study

Objective

Neurologic complications seriously affect the survival rate and quality of life in patients with extracorporeal cardiopulmonary resuscitation (ECPR) undergoing cardiac arrest. This study aimed to repurpose selective hypothermic cerebral perfusion (SHCP) as a novel approach to protect the brains of these patients.

Methods

Rats were randomly allocated to Sham, ECPR, and SHCP combined ECPR (CP-ECPR) groups. In the ECPR group, circulatory resuscitation was performed at 6 minutes after asphyxial cardiac arrest by extracorporeal membrane oxygenation. The vital signs were monitored for 3 hours, and body and brain temperatures were maintained at the normal level. In the CP-ECPR group, the right carotid artery catheterization serving as cerebral perfusion was connected with the extracorporeal membrane oxygenation device to achieve selective brain cooling (26-28 °C). Serum markers of brain injury and pathomorphologic changes in the hippocampus were evaluated. Three biological replicates further received RNA sequencing in ECPR and CP-ECPR groups. Microglia activation and inflammatory cytokines in brain tissues and serum were detected.

Results

SHCP rapidly reduced the brain-targeted temperature and significantly alleviated nerve injury. This was evident from the reduced brain injury serum biomarker levels, lower pathologic scores, and more surviving neurons in the hippocampus in the CP-ECPR group. Furthermore, more differentially expressed genes for inflammatory responses were clustered functionally according to Kyoto Encyclopedia of Genes and Genomes pathway analysis. And SHCP reduced microglia activation and the release of proinflammatory mediators.

Conclusions

Our preliminary data indicate that SHCP may serve as a potential therapy to attenuate brain injury via downregulation of neuroinflammation in patients with ECPR.

Accidental Hypothermia: 2021 Update

Accidental hypothermia is an unintentional drop of core temperature below 35 °C. Annually, thousands die of primary hypothermia and an unknown number die of secondary hypothermia worldwide. Hypothermia can be expected in emergency patients in the prehospital phase. Injured and intoxicated patients cool quickly even in subtropical regions. Preventive measures are important to avoid hypothermia or cooling in ill or injured patients. Diagnosis and assessment of the risk of cardiac arrest are based on clinical signs and core temperature measurement when available. Hypothermic patients with risk factors for imminent cardiac arrest (temperature < 30 °C in young and healthy patients and <32 °C in elderly persons, or patients with multiple comorbidities), ventricular dysrhythmias, or systolic blood pressure < 90 mmHg) and hypothermic patients who are already in cardiac arrest, should be transferred directly to an extracorporeal life support (ECLS) centre. If a hypothermic patient arrests, continuous cardiopulmonary resuscitation (CPR) should be performed. In hypothermic patients, the chances of survival and good neurological outcome are higher than for normothermic patients for witnessed, unwitnessed and asystolic cardiac arrest. Mechanical CPR devices should be used for prolonged rescue, if available. In severely hypothermic patients in cardiac arrest, if continuous or mechanical CPR is not possible, intermittent CPR should be used. Rewarming can be accomplished by passive and active techniques. Most often, passive and active external techniques are used. Only in patients with refractory hypothermia or cardiac arrest are internal rewarming techniques required. ECLS rewarming should be performed with extracorporeal membrane oxygenation (ECMO). A post-resuscitation care bundle should complement treatment.

Regression model for predicting core body temperature in infrared thermal mass screening

With fever being one of the most prominent symptoms of COVID-19, the implementation of fever screening has become commonplace around the world to help mitigate the spread of the virus. Non-contact methods of temperature screening, such as infrared (IR) forehead thermometers and thermal cameras, benefit by minimizing infection risk. However, the IR temperature measurements may not be reliably correlated with actual core body temperatures. This study proposed a trained model prediction using IR-measured facial feature temperatures to predict core body temperatures comparable to an FDA-approved product. The reference core body temperatures were measured by a commercially available temperature monitoring system. Optimal inputs and training models were selected by the correlation between predicted and reference core body temperature. Five regression models were tested during the study. The linear regression model showed the lowest minimum-root-mean-square error (RSME) compared with reference temperatures. The temple and nose region of interest (ROI) were identified as optimal inputs. This study suggests that IR temperature data could provide comparatively accurate core body temperature prediction for rapid mass screening of potential COVID cases using the linear regression model. Using linear regression modeling, the non-contact temperature measurement could be comparable to the SpotOn system with a mean SD of ± 0.285 °C and MAE of 0.240 °C.

Gossypiboma during orthognathic surgery: A case report

INTRODUCTION

Dislodgment of nasopharyngeal temperature probes and/or unretrieved device fragments (UDFs) or gossypibome at a patient's hypopharynx is rare complication after orthognathic surgery that may occur as a result of surgical manipulation or may be a consequence of factors related to the insertion and handling of the probe after extubation. However, the exact mechanism of this complication is unknown. To the best of our knowledge, this is the 1st reported case of a missing temperature probe after orthognathic surgery.

CASE PRESENTATION

We report the case of a patient who suffered from dislodgment of a 12-cm temperature probe after orthognathic surgery. The surgery was uneventful. At the end of the surgery, the probe was believed to have been completely removed from the nasal cavity. The nasopharyngeal cavity was visually inspected while the patient was still under anaesthesia and the trachea was still intubated. Extubation was successful, and the patient was moved to the recovery area. The patient was discharged from the hospital one day after resuming an oral fluid diet. At the follow-up visit on the 4th postoperative day, the patient presented with mild symptoms of a sore throat and cough. At the follow-up visit in the 3rd postoperative week, the patient reported one episode of vomiting and severe coughing, and the patient ultimately retrieved the 12-cm temperature probe from her mouth.

DISCUSSION

After conducting a systematic literature review, we discuss surgical cases involving UDFs or gossypiboma. We also describe changes in our clinical practice after this event, and we envision that these modifications will have a positive influence on patient care. We believe that alternative routes for inserting temperature probes with covers would be suitable for orthognathic surgery.

CONCLUSION

Vigilance should be maintained during patient extubation by both teams (surgeons and anaesthetists) to assure that part of the probe always remains visible outside the oral/nasal cavity as well as complete removal of the device to avoid this life-threating complication.

Reliability of alternative devices for postoperative patient temperature measurement: two prospective, observational studies

Peri-operative hypothermia is associated with significant morbidity, yet limitations exist regarding non-invasive temperature assessment in the post-anaesthesia care unit (PACU). In this prospective study of 100 patients, we aimed to determine the reliability of two commonly used temperature measurement devices, forehead temporal artery temperature and tympanic measurement, in addition to an indwelling urinary catheter with temperature probe, in comparison with the final nasopharyngeal core temperature at the end of surgery. Agreement of forehead measurement with nasopharyngeal temperature showed a mean bias (±95% limits of agreement) of 0.15 °C (±1.4 °C), with a steep slope of the relationship on the Bland-Altman plot of -0.8, indicating a tendency to normalise patient temperature readings to 36.4 °C. Only 54% of hypothermic cases were correctly detected by the forehead measurement device. Agreement of tympanic measurement with nasopharyngeal core temperature measurement was marginally improved with a mean bias of 0.13 °C (95% limits of agreement ±1.15 °C). In contrast, agreement of bladder temperature with nasopharyngeal temperature showed a mean (SD) bias of 0.19 (0.28) °C (95% limits of agreement ±0.54 °C), with a relatively flat line of best fit. We demonstrated that two commonly used temperature measurement devices, forehead temporal artery temperature and tympanic measurement, compared with nasopharyngeal core temperature, were imprecise and unreliable following major surgery. However, the indwelling catheter with temperature sensor was precise and acceptable for continuous core temperature measurement in the PACU.

Accuracy and precision of zero-heat-flux temperature measurements with the 3M™ Bair Hugger™ Temperature Monitoring System: a systematic review and meta-analysis

Zero-heat-flux thermometers provide clinicians with the ability to continuously and non-invasively monitor body temperature. These devices are increasingly being used to substitute for more invasive core temperature measurements during surgery and in critical care. The aim of this review was to determine the accuracy and precision of zero-heat-flux temperature measurements from the 3M™ Bair Hugger™ Temperature Monitoring System. Medline and EMBASE were searched for studies that reported on a measurement of core or peripheral temperature that coincided with a measurement from the zero-heat-flux device. Study selection and quality assessment was performed independently using the Revised Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2). The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach was used to summarize the strength of the evidence. Pooled estimates of the mean bias and limits of agreement with outer 95% confidence intervals (population limits of agreement) were calculated. Sixteen studies were included. The primary meta-analysis of zero-heat-flux versus core temperature consisted of 22 comparisons from 16 individual studies. Data from 952 participants with 314,137 paired measurements were included. The pooled estimate for the mean bias was 0.03 °C. Population limits of agreement, which take into consideration the between-study heterogeneity and sampling error, were wide, spanning from - 0.93 to 0.98 °C. The GRADE evidence quality rating was downgraded to moderate due to concerns about study limitations. Population limits of agreement for the sensitivity analysis restricted to studies rated as having low risk of bias across all the domains of the QUADAS-2 were similar to the primary analysis. The range of uncertainty in the accuracy of a thermometer should be taken into account when using this device to inform clinical decision-making. Clinicians should therefore consider the potential that a temperature measurement from a 3M™ Bair Hugger™ Temperature Monitoring System could be as much as 1 °C higher or lower than core temperature. Use of this device may not be appropriate in situations where a difference in temperature of less than 1 °C is important to detect.

Zero-heat-flux core temperature monitoring system: an observational secondary analysis to evaluate agreement with naso-/oropharyngeal probe during anesthesia

General anesthesia impairs thermoregulation and contributes to perioperative hypothermia; core body temperature monitoring is recommended during surgical procedures lasting > 30 min. Zero-heat-flux core body temperature measurement systems enable continuous non-invasive perioperative monitoring. During a previous trial evaluating the benefits of preoperative forced-air warming, intraoperative temperatures were measured with both a zero-heat-flux sensor and a standard naso-/oropharyngeal temperature probe. The aim of this secondary analysis is to evaluate their agreement. ASA I-III patients, scheduled for elective, non-cardiac surgery under general anesthesia, were enrolled. A zero-heat-flux sensor was placed on the participant's forehead preoperatively. Following induction of anesthesia, a "clinical" temperature probe was placed in the nasopharynx or oropharynx at the anesthesiologist's discretion. Temperature measurements from both sensors were recorded every 10 s. Agreement was analyzed using the Bland-Altman method, corrected for repeated measurements, and Lin's concordance correlation coefficient, and compared with existing studies. Data were collected in 194 patients with a median (interquartile range) age of 60 (49-69) years, during surgical procedures lasting 120 (89-185) min. The zero-heat-flux measurements had a mean bias of - 0.05 °C (zero-heat-flux lower) with 95% limits of agreement within - 0.68 to + 0.58 °C. Lin's concordance correlation coefficient was 0.823. The zero-heat-flux sensor demonstrated moderate agreement with the naso-/oropharyngeal temperature probe, which was not fully within the generally accepted ± 0.5 °C limit. This is consistent with previous studies. The zero-heat-flux system offers clinical utility for non-invasive and continuous core body temperature monitoring throughout the perioperative period using a single sensor.