Relationship among oxygen flow or the amount of wetting liquid and oxygen noise / 现代临床护理

Objective To investigate the relationship among the oxygen flow or the amount of wetting liquid in humidification bottle and oxygen noise.Method Distilled water were added to one third or half of two sets of oxygen humidification bottle device as the humidification fluid,the noise value generated in the flow rate of 2 L/min,5L/min by two set of inspired oxygen apparatus were recorded.Results Different noise value with same capacity humidifying fluid but different oxygen flow was statistically significant(all P<0.01),the more flow of oxygen the greater the noise; Different noise value generated by the same oxygen flow but different capacity humidifying liquid oxygen was statistically significant(all P<0.01),more humidification fluid,greater the noise. Conclusion Noise generated with the increasing oxygen flow rate and the amount of wetting liquid.

Development and application of the digital wireless network billing system in oxygen flow / 中国实用护理杂志

Objective To investigate the development of the digital wireless network billing system of oxygen flow in clinical application. Methods By random 220 cases of patients who need to absorb oxygen were divided into the observation group(108 cases)and the control group(112 cases), the observation group used the digital wireless network billing system of oxygen flow, and the control group adopted the traditional buoy type oxygen gauge instrument. The following items were compared between the two groups: dispute rates between nurses and patients for different amount of absorbed oxygen, the average time cost for nurses in measuring the duration of oxygen absorbing, total income per barrel for recycling oxygen. Results For the dispute rates between nurses and patients for different amount of absorbed oxygen were 0.93% in the observation group, and 75.89% in the control group. The average time cost for nurses in measuring the duration of oxygen absorbing was 2.03 minutes for the observation group, and 12.54 minutes for the control group; total income per barrel for recycling oxygen was 42.68 yuan per barrel of the observation group, and 28.23 yuan in the control group. The statistical analysis between the two groups was supported by 95% confidential level. Conclusions Using the digital wireless network billing system of oxygen flow in clinical can reduce the dispute rates between the nurses and patients, improve patients' satisfaction degree, reduce the total time cost for nurses in measuring the duration of oxygen absorbing, raise efficiency, build a clear scientific charge system of oxygen flow, and restore economic loss.

The effects of the oxygen flow rate on heart rate variability in the PACU after TIVA

BACKGROUND: Oxygen increases the cardiac vagal tone, blood pressure, systemic vascular resistance and vascular tone in healthy adults.This study assessed the autonomic tone according to different oxygen flow rates via different types of masks with using the heart rate variability (HRV) in the PACU after total intravenous anesthesia (TIVA). METHODS: We prospectively studied 27 patients after TIVA in the PACU.The 5 L group received oxygen via a simple mask with an oxygen rate of 5 L/min and the 10 L group received oxygen via a mask with a reservoir bag at a rate of 10 L/min in the PACU. We evaluated the HRV at the point of stabilization before anesthesia (BL), 5 min in the PACU (PACU 5), 30 min in the PACU (PACU 30) and 60 min in the PACU (PACU 60). RESULTS: In the 5 L group, the nuHF was increased to 42.4 +/- 24.2 at 60 min in the PACU as compared with 27.1 +/- 19.1 at 5 min in the PACU.In the 5 L group, the LFHFr was decreased to 2.3 +/- 2.1 at PACU 60 as compared with 6.6 +/- 9.7 at PACU 5 and the nuLF was decreased to 56.9 +/- 23.2 at PACU 60 as compared with 72.9 +/- 19.0 at PACU 5.There were no significant changes between the two groups at PACU 5, PACU 30 and PACU 60.The oxygen saturation was increased at PACU 60 compared with PACU 5 in the two groups. CONCLUSIONS: These finding indicates that 1 h of oxygen administration with 5 L/min during emergence from anesthesia increased the relative vagal tone, and the arterial blood pressure is stable irrespective of the oxygen flow rate.

The Effect of Different Oxygen Flow Rates on Arterial Oxygenation and End-Tidal CO2 Measurements via a Nasal Cannula in Spinal Anesthesia / 대한마취과학회지

BACKGROUND: The monitoring of end-tidal carbon dioxide tension (PETCO2) and oxygen supply may be required in spontaneously breathing patients during spinal anesthesia, particulary in cases involving high spinal block, underlying pulmonary disease, and use of a sedative drug. We investigated changes in PETCO2 and arterial oxygen tension versus oxygen flow rate via a nasal cannula, and the correlation between arterial carbon dioxide tension (PaCO2) and PETCO2 in spontaneously breathing patients during spinal anesthesia. METHODS: Thirty adult patients participated in this study. We performed spinal anesthesia with an optimal dose of heavy marcaine. After determining the sensory blockade level, PETCO2 was sampled from hub of a 14-gauge central catheter piercing one of the two nasal oxygen prongs, and oxygen flow rates (2, 3, 4 or 5 L/min) were measured by on-line capnography. The oxygen flow rates were varied every 5 minutes, and PETCO2 values and arterial samples for PaCO2 and arterial oxygen tension (PaO2) analysis were obtained at the end of each 5-minute period. RESULTS: No significant difference in PETCO2 was observed at the different oxygen flow rates. The results show that PETCO2 correlates closely with PaCO2 irrespective of oxygen flow rate. The PaO2 values were; 155.7 +/- 26.3, 192.7 +/- 36.6, 217.0 +/- 40.6 and 241.4 +/- 51.3 mmHg at nasal oxygen flow rates of 2, 3, 4 and 5 L/min, respectively. CONCLUSIONS: The measurement of PETCO2 via this nasal cannula was useful for continuous, noninvasive monitoring during spinal anesthesia irrespective of oxygen flow rate.

The Effect of Oxygen Inflow Rate and Tidal Volume on Excretion of Nitrous Oxide by Pharmacokinetic Study / 대한마취과학회지

BACKGROUND: There are few literatures which show the role of tidal volume on the excretion of nitrous oxide(N2O). The purpose of this study is to pharmacokinetically evaluate the effect of varying oxygen inflow rates and tidal volumes on the excretion of N2O. METHODS: Ten patients undergoing general anesthesia on supine position were selected. Administering N2O 3 L/min and oxygen 2 L/min with enflurane, ventilatory pattern was tidal volume 10 mL/kg and respiratory rate 11/min. Administration of N2O was stopped after 30 minutes, when end-tidal N2O concentration(ETN2O) were near 60% at steady state. Oxygen was given at 4 L/min with tidal volume(VT) 8 mL/kg(treatment 1), 4 L/min with VT 16 mL/kg (treatment 2), 8 L/min with VT 8 mL/kg(treatment 3) and 8 L/min with VT 16 mL/kg(treatment 4). ETN2O was measured every 15 seconds for first 3 minutes and every 1 minute thereafter. The order of 4 treatments were determined with bloc randomization. The time interval between treatments was 30 minutes. Pharmacokinetic parameters were obtained using PKCALC data program. RESULTS: Area under curve and clearance in treatments 1 and 2 were significantly larger than those in treatments 3 and 4. Mean residence time and half-life in treatment 4 were significantly shorter than those in other treatments. CONCLUSIONS: The oxygen inflow rate enhances the excretion of N2O more than the tidal volume does, and the tidal volume does so when the oxygen inflow rate is 8 L/min.

The Effects of Different Oxygen Flow on End-Tidal N2O after Nitrous Oxide/Oxygen Anesthesia / 대한마취과학회지

Nitrous oxide is the most commonly used inhaled anesthetic in the part of anesthesia and used up to 75% of concentrations. Diffusion hypoxia among the disadvantages or harmful damages due to nitrous oxide exposure must be prevented by moderate flow (4-6 liters/minute) of oxygen for a few minutes. This study was investigated the effect of the amount of oxygen flow on the speed of removal of exposed nitrous oxide followed by oxygen flow rate of 2, 4, and 6 liters/minute when halted the administration of nitrous oxide. These variables were taken in 57 patients of 16 to 60 years old, who were performed the elective surgery. All patients were anesthetized with the 0.5-1.5 MAC of enflurane or isoflurane combined with nitrous oxide(2 liters/minute) and oxygen(2 liters/minute), and paralyzed with IV route pancuronium 0.07-0.08 mg/kg. Ventilation was controlled with Ohmeda 7000 ventilator (BOC Health Care Inc, Madison, USA), using a constant tidal volume of 10 ml/Kg of ideal body weight. Ventilatory rate was adjusted 12 times/minute to maintain the end-tidal CO2 of 20-35 mmHg. After 60 to 90 minutes of anesthesia, the nitrous oxide/oxygen mixture was changed to 100% oxygen, but ventilation being held constant. The results were as follows; 1) After the first 30 seconds, the end-tidal nitrous oxide concentration was 39.6+/-+3.7% in 2 liters/minute of oxygen flow, 28.2+/-5% in 4 liters/minute and 23.4+/-6.3% in 6 liters/minute. 2) After the 2 minutes, the end-tidal nitrous oxide concentration was 29.1+/-3.6% in 2 liters/minute of oxygen flow, 14.4+/-3.2% in 4 liters/minute and 10.13+/-2% in 6 liters/minute. 3) After the 5 minutes and 30 seconds, the end-tidal nitrous oxide concentration was 16.4+/-3.3% in 2 liters/minute of oxygen flow, 5.5+/-1.9% in 4 liters/minute and 4.0+/-1.7% in 6 liters/minute. 4) After 15 minutes, the end tidal nitrous oxide was 7.5+/-2.1% in 2 liters/minute of oxygen flow, 2.3+/-0.7% in 4 liters/minute and 2.0+/-0.8% in 6 liters/minute. In conclusion, the larger size of oxygen flow, the more rapid elimination of nitrous oxide. The removal rate of nitrous oxide was greatest at first 30 seconds after halting the nitrous oxide administration in all cases.

Effects of Oxygen Flow and the Length of Corrugate Tube as a Reservoir on the Resuscitation Bag / 대한마취과학회지

Resuscitation bag (RB) is widely used for artificial ventilation and adequate ventilation during resuscitation, or for patient transport, when high concentration of inspired oxygen (70-100%) must be supplied. The purpose of this study was to investigate the effect of oxygen flow and the length of corrugated tube as a reservoir on the oxygen concentration in the adult type and pediatric type resuseitation bag. Each 24 mm corrugated tube (0, 20,40, 60, 80, 100 cm) was attached to the inlet valve, oxygen flow of 1, 3, 5, 7, 9, 11, 13 or 15 L/min was delivered to oxygen inlet site of RB. and oxygen concentration was measured for 10 times. To eliminate the possibility that ventilatory pattern affect the oxygen concentration, RB was manually handled with normal ventilatory pattern ; in advlt type, tidal volume was 800 cc, respiratory rate was 10/min and 1:E ratio was 1:2, in pediatric type, tidal volume was 100 cc, respiratory rate was 20/min and 1:E ratio was 1:2. In adult RB, a 15 L oxygen flow without reservoir delivered less than 50% oxygen. To get more than 70% oxygen, one must administer more than a 15 L oxygen flow with reservoir of 60 cm corrugated tube, oxygen flow of 9 L/min with 80 cm corrugated tube or a 7 L flow of oxygen with 100 cm corrugated tube. And to provide more than 80%, oxygen of more than a 11 L flow with reservoir of 100 cm should be delivered. In pediatric RB, a 15 L oxygen flow without reservoir get more than 70% oxygen. A 20 cm corrugated tube as a reservoir increased abruptly oxygen concentration, and A 40 cm tube with more than a 7 L flow delivered more than 95% oxygen, but above 60cm tube there is little increase in the oxygen concentration. These results indicated that to get more than 70% oxygen, 60 cm and 40 cm corrugated tube is required in adult type RB and pediatric type RB respectively as an oxygen reservoir.

The Study of Oxygen Therapy with Modified T - piece in Pediatric Patients after Open Heart Surgery / 대한마취과학회지

Oxygen therapy is the important method of critical care especially to pediatric patients of post-open heart surgery. The purpose of this study is to investigate the effect of oxygen therspy with modified T-piece in pediatric patients. We supply oxygen via modified T-piece after ventilatory weaning as following rates in turn : group 1; 0.05L/min/kg, group 2; 0.1L /min/kg, group 3; 0.3L/nun/kg, group 4; 0.5L/min/kg. Arterial blood gas analysis was done and heart rate, systolic and diastolic blood pressure, body temperature and oxygen sat uration were recorded. We defined absolute oxygen flow as oxygen flow/weight x weight. The relationshiop between oxygen flow/weight or absolute oxygen flow and PaO2 SaO2, was statistically significant. We got the regression equation as following : PaO2,=119.7xoxygen flow/weight+132.7 (R2=0.13), SaO2=3.2xoxygen flow/weight+97.9 (R2=0.11), PaO2=6.7Xabsolute oxygen flow+141.6 (R2=0.11), SaO2=0.16Xabsolute oxygen flow+96.2 (R2= 0.1). There were significant factors, by which PaO2, was influenced, such as oxygen flow/ weight(Pearson correlation coefficient, r=0.34), absolute oxygen flow(r=0.37), SaO2(r= 0.57), heart rate(r=-0.35), body temperature(r=0.21). As the result of mutiple regression analysis of these factors, we got the regression equation as following : PaO2=-1254.8+67.1Xoxygen flow/weight+14.5XSa0-1.6XPaCO2-0.5XheartXrate+ 2.7Xbody tempersture (R2= 0.44), PaO2=-1240+5.4Xabsolute oxygen flow+14.0XSaO2-1.4 PaCO2-0.6Xheart rate+4.0 body temperature-2.1Xweight (R2=0.46) It were group 1; 0.66, group 2; 0.69, group 3; 0.71, group 4; 0.75 that were calculated FIO2 using AaDO2 in case of FIO2=1.0 and increased significantly. However, because R2 that we got in the regression equation is too small, even though there is statistical significance, we think that clinical application of the result of our study is difficult.

The Study of Oxygen Therapy with Modified T - piece in Pediatric Patients after Open Heart Surgery / 대한마취과학회지

Oxygen therapy is the important method of critical care especially to pediatric patients of post-open heart surgery. The purpose of this study is to investigate the effect of oxygen therspy with modified T-piece in pediatric patients. We supply oxygen via modified T-piece after ventilatory weaning as following rates in turn : group 1; 0.05L/min/kg, group 2; 0.1L /min/kg, group 3; 0.3L/nun/kg, group 4; 0.5L/min/kg. Arterial blood gas analysis was done and heart rate, systolic and diastolic blood pressure, body temperature and oxygen sat uration were recorded. We defined absolute oxygen flow as oxygen flow/weight x weight. The relationshiop between oxygen flow/weight or absolute oxygen flow and PaO2 SaO2, was statistically significant. We got the regression equation as following : PaO2,=119.7xoxygen flow/weight+132.7 (R2=0.13), SaO2=3.2xoxygen flow/weight+97.9 (R2=0.11), PaO2=6.7Xabsolute oxygen flow+141.6 (R2=0.11), SaO2=0.16Xabsolute oxygen flow+96.2 (R2= 0.1). There were significant factors, by which PaO2, was influenced, such as oxygen flow/ weight(Pearson correlation coefficient, r=0.34), absolute oxygen flow(r=0.37), SaO2(r= 0.57), heart rate(r=-0.35), body temperature(r=0.21). As the result of mutiple regression analysis of these factors, we got the regression equation as following : PaO2=-1254.8+67.1Xoxygen flow/weight+14.5XSa0-1.6XPaCO2-0.5XheartXrate+ 2.7Xbody tempersture (R2= 0.44), PaO2=-1240+5.4Xabsolute oxygen flow+14.0XSaO2-1.4 PaCO2-0.6Xheart rate+4.0 body temperature-2.1Xweight (R2=0.46) It were group 1; 0.66, group 2; 0.69, group 3; 0.71, group 4; 0.75 that were calculated FIO2 using AaDO2 in case of FIO2=1.0 and increased significantly. However, because R2 that we got in the regression equation is too small, even though there is statistical significance, we think that clinical application of the result of our study is difficult.

Gas Exchange during Apneic Oxygenation / 대한마취과학회지

Arterial and mixed venous blood gases were investigated during apnea in anesthetized paralyzed mongrel dogs. Dogs were ventilated with 100% oxygen after endotracheal intubation by intermittent positive pressure ventilation over 30 minutes before apnea. Femoral artery was cannulated for arterial blood gas analysis and Swan-Ganz catheter was inserted through femoral vein to draw mixed venous blood for gas analysis. In group 1 (n=6), the endotracheal tube was left open to room air during apnea and blood gas analysis were measured at 1 minute interval. In group 2 (n=6), the endotracheal tube was left connected to the respirator with 100% oxygen with 1 L/kg/min flow during apnea and blood gas analysis were checked at 5 minute interval. Blood sampling was continued until cardiac problem occured. In group1, PaO2,fall rapidly below 100 mmHg in 5 minutes and PaCO2, increased by the rate of 5.2 mmHg/min, In group 2, PaO2, fall slowly in proportion to increase of PaCO2, that rised in the rate of 4.1 mmHg/min, but hypoxemia does not occured until 45 minutes. In conclusion, arterial oxygenation can be maintained for long duration with oxygen flow through endotracheal tube but arterial carbon dioxide tension increase continuously during apnea. Useful methods to avoid carbon dioxide accumulation should be sought and investigated for clinical use of apneic oxygenation.

Gas Exchange during Apneic Oxygenation / 대한마취과학회지

Arterial and mixed venous blood gases were investigated during apnea in anesthetized paralyzed mongrel dogs. Dogs were ventilated with 100% oxygen after endotracheal intubation by intermittent positive pressure ventilation over 30 minutes before apnea. Femoral artery was cannulated for arterial blood gas analysis and Swan-Ganz catheter was inserted through femoral vein to draw mixed venous blood for gas analysis. In group 1 (n=6), the endotracheal tube was left open to room air during apnea and blood gas analysis were measured at 1 minute interval. In group 2 (n=6), the endotracheal tube was left connected to the respirator with 100% oxygen with 1 L/kg/min flow during apnea and blood gas analysis were checked at 5 minute interval. Blood sampling was continued until cardiac problem occured. In group1, PaO2,fall rapidly below 100 mmHg in 5 minutes and PaCO2, increased by the rate of 5.2 mmHg/min, In group 2, PaO2, fall slowly in proportion to increase of PaCO2, that rised in the rate of 4.1 mmHg/min, but hypoxemia does not occured until 45 minutes. In conclusion, arterial oxygenation can be maintained for long duration with oxygen flow through endotracheal tube but arterial carbon dioxide tension increase continuously during apnea. Useful methods to avoid carbon dioxide accumulation should be sought and investigated for clinical use of apneic oxygenation.