通过气泡式湿化器和鼻导管输送氧气的准确性。

Accuracy of oxygen delivery through bubble humidifiers and nasal catheters.

机构信息

Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA.

出版信息

Vet Anaesth Analg. 2020 May;47(3):356-367. doi: 10.1016/j.vaa.2020.01.004. Epub 2020 Feb 8.

DOI:10.1016/j.vaa.2020.01.004

PMID:32223959

Abstract

OBJECTIVE

To evaluate the equipment used for nasal insufflation of oxygen and determine its accuracy.

STUDY DESIGN

Original study.

METHODS

Oxygen delivery assemblies consisting of a flowmeter, bubble humidifier, oxygen delivery tubing and nasal insufflation catheters were assembled. Single and double catheter assemblies were made for four sizes of nasogastric feeding tubes (3.5 Fr, 5.0 Fr, 8.0 Fr and 10.0 Fr) resulting in 64 individual assemblies. A gas flow analyzer measured oxygen flow at the tip of the nasal catheter assemblies and from the pressure relief valve (PRV) of the bubble humidifiers. Statistical analyses were conducted to assess the functionality of assemblies. For functional assemblies, the accuracy of oxygen flow relative to the prescribed flow settings was determined.

RESULTS

Catheter size was significantly associated with the functionality of assemblies. Probability (95% confidence interval) of 3.5 Fr, 5.0 Fr and 8.0 Fr assemblies being functional was estimated at 0.53 (0.14, 0.89), 0.83 (0.36, 0.98) and 0.98 (0.76, 0.99), respectively. All 10.0 Fr assemblies were functional. Functional assemblies, in general, consistently under-delivered the prescribed flow because a large portion of set flow was diverted through the bubble humidifier PRV.

CONCLUSIONS

Leaks through the PRV cause significant diversion of oxygen prior to it reaching the catheter tips. Smaller patients are particularly susceptible, as small catheters limit oxygen delivery creating proportionally greater leaks through the PRV.

CLINICAL RELEVANCE

It was not possible to accurately deliver oxygen because of leaks through the PRV. Targeting a specific outcome (e.g., oxyhemoglobin saturation > 94%, PaO 80-120 mmHg; 11-16 kPa) and avoiding unnecessarily high fractions of inspired oxygen cannot be done if flow delivery cannot be accurately assured. One possible solution would be to use a bubble humidifier with a 6 psi PRV that does not leak prior to reaching the opening pressure.

摘要

目的

评估用于鼻内给氧的设备并确定其准确性。

研究设计

原始研究。

方法

组装由流量计、气泡式湿化器、给氧管和鼻内给氧导管组成的给氧装置。为 4 种规格的鼻胃管（3.5Fr、5.0Fr、8.0Fr 和 10.0Fr）制作单导管和双导管组件，共 64 个组件。气体流量分析仪测量鼻导管组件尖端和气泡式湿化器减压阀（PRV）的氧气流量。进行统计学分析以评估组件的功能。对于功能组件，确定相对于规定流量设置的氧气流量的准确性。

结果

导管尺寸与组件的功能显著相关。3.5Fr、5.0Fr 和 8.0Fr 组件的功能概率（95%置信区间）估计分别为 0.53（0.14，0.89）、0.83（0.36，0.98）和 0.98（0.76，0.99）。所有 10.0Fr 组件均具有功能。功能组件通常会输送低于规定流量的氧气，因为大部分设定流量会通过气泡式湿化器 PRV 分流。