Journal of clinical monitoring and computing
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J Clin Monit Comput · Apr 2018
Letter Case ReportsAn abrupt reduction in end tidal carbon di oxide concentration in a mechanically ventilated patient in neurocritical care ward: a capnogram artifact.
In patients with normal lung and reasonable cardiac function such as head injury patients, the PETCo2 can be used as a surrogate for partial pressure of Carbon dioxide (PaCO2) in mechanically ventilated patients. Thus early interpretation and accurate assessment of capnogram is crucial in neurocritical care patients. Here we present and discuss a scenario where in connection of a jet nebulizer to the ventilator lead to abrupt decrease in end tidal carbon dioxide leading to a diagnostic dilemma. Also this report highlights and discusses the importance of the proper placement of breathing circuit components to ensure accurate CO2 readings in particular the use of a jet nebulizer.
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J Clin Monit Comput · Apr 2018
Performance of a capnodynamic method estimating effective pulmonary blood flow during transient and sustained hypercapnia.
The capnodynamic method is a minimally invasive method continuously calculating effective pulmonary blood flow (COEPBF), equivalent to cardiac output when intra pulmonary shunt flow is low. The capnodynamic equation joined with a ventilator pattern containing cyclic reoccurring expiratory holds, provides breath to breath hemodynamic monitoring in the anesthetized patient. Its performance however, might be affected by changes in the mixed venous content of carbon dioxide (CvCO2). ⋯ During prolonged hypercapnia, agreement remained good during changes in CO. The mean polar angle was -4.19° (-8.8° to 0.42°). Capnodynamic COEPBF is affected but recovers rapidly after transient large changes in PvCO2 and preserves good agreement and trending ability during states of prolonged hypercapnia at different levels of CO.
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J Clin Monit Comput · Apr 2018
A validation method for near-infrared spectroscopy based tissue oximeters for cerebral and somatic tissue oxygen saturation measurements.
We describe the validation methodology for the NIRS based FORE-SIGHT ELITE® (CAS Medical Systems, Inc., Branford, CT, USA) tissue oximeter for cerebral and somatic tissue oxygen saturation (StO2) measurements for adult subjects submitted to the United States Food and Drug Administration (FDA) to obtain clearance for clinical use. This validation methodology evolved from a history of NIRS validations in the literature and FDA recommended use of Deming regression and bootstrapping statistical validation methods. For cerebral validation, forehead cerebral StO2 measurements were compared to a weighted 70:30 reference (REF CXB) of co-oximeter internal jugular venous and arterial blood saturation of healthy adult subjects during a controlled hypoxia sequence, with a sensor placed on the forehead. ⋯ With informed consent, 24 subjects successfully completed the somatic validation study. The bias and precision of somatic StO2 compared to REF CXS was 0.04 ± 4.22% from the average of flank, quadriceps, and calf StO2 measurements to best represent the global whole body REF CXS. The NIRS validation methods presented potentially provide a reliable means to test NIRS monitors and qualify them for clinical use.
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J Clin Monit Comput · Apr 2018
Short term general anesthesia for retro-bulbar block in ophthalmic surgery generates no significant hypercapnia.
To assess the impact of short time hypnosis for retro-bulbar anesthesia on ventilation in patients undergoing ophthalmic surgery of the anterior eye chamber. In all patients, a combined continuous transcutaneous carbon dioxide tension (PtcCO2) and partial oxygen saturation (SpO2) measurement was applied in addition to routine monitoring. To enable unconscious application of retro-bulbar anesthesia, intravenous thiopental was given in one to multiple bolus doses. ⋯ Higher PtcCO2 values were associated with the presence of hypertension and smoking. Apnea (p < 0.001) and recovery (p = 0.003) time were significantly prolonged in the patients needing the Esmarch maneuver. Short term anesthesia with thiopental in ophthalmic surgery is associated with a mild but not clinically relevant hypercapnia.
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J Clin Monit Comput · Apr 2018
Randomized Controlled Trial Comparative StudyComparison of Univent tube and EZ blocker in one lung ventilation; airway pressures and gas exchange.
Univent tube (UT) and EZ-blocker were used for one-lung ventilation (OLV). UT is a single lumen tube with a small separate lumen containing a bronchial blocker. EZ-blocker differs with its unique y-shaped double-cuffed distal end. ⋯ ABG findings and haemodynamic variables were similar. EZ and Univent tube affected the airway pressures, oxygenation, ventilation and haemodynamic variables similarly during OLV in patients with normal respiratory function. These devices can be alternatives to each other based on clinical conditions.