BACKGROUND: An excessive endotracheal cuff pressure can cause tracheal injury, and insufficient cuff pressure may not generate an effective cuff seal. The peak inspiratory pressure influences the minimal occlusion pressure of the endotracheal tube cuff. However, the relationship between the minimal occlusion pressure and the tidal volume has not been investigated. This study was conducted to estimate the relationship between the tidal volume and the minimal occlusion pressure of the cuff. METHODS: Ten mechanically ventilated patients were included. The minimal occlusion pressure of the cuff was measured using a pressure gauge. The basal tidal volume was increased and decreased as much as 10% whilst maintaining the same peak inspiratory pressure. The, minimal occlusion pressures were then measured in the high and low tidal volume state, respectively. RESULTS: The peak inspiratory pressure was 32.6+/-.72 cmH2O and the minimal occlusion pressure was 19.0+/-2.26 mmHg in the basal ventilator setting. There was a significant relationship between the peak inspiratory pressure and the minimal occlusion pressure(r=0.77, p<0.01). The minimal occlusion pressure of the cuff was increased to 20.3+/-2.4 mmHg in the high tidal volume state(p<0.05), and decreased to 16.8+/-3.01 mmHg in the low tidal volume state (p<0.001). CONCLUSION: The minimal occlusion pressure of the cuff can be influenced by changes in the tidal volume as well as by the peak inspiratory pressure.
Humans ; Tidal Volume* ; Ventilators, Mechanical

BACKGROUND: The objective of this study was to observe that the effect on the elimination of apparatus dead space was different according to modes of ventilation. METHODS: In 30 patients undergoing esophageal surgery, we placed a double-lumen endobronchial tube in the midtrachea and used the bronchial lumen with a conventional Y connector while the tracheal lumen was clamped for conventional ventilation (CV) or used both lumens with special connectors that separated the inspiratory limb and the expiratory limb for separated ventilation (SV). Four ventilation modes were used in each patient. Type CV10 is a mode with 10 ml/kg of tidal volume, and a frequency of 10/min, and type CV5 is a mode with 5 ml/kg of tidal volume, and a frequency of 20/min. Except for the special connectors, type SV10 and SV5 are the same as CV10 and CV5, respectively. RESULTS: The means standard deviations of PaCO2 in CV10, SV10, CV5, and SV5 were 34.8 +/- 5.7 mmHg, 32.3 +/- 5.1 mmHg, 39.2 +/- 6.6 mmHg, and 34.9 +/- 5.9 mmHg, respectively. The PaCO2 in SV10 and SV5 decreased significantly when compared with that seen in CV10 and CV5, respectively (P <0.001), showing the effect of the elimination of apparatus dead space. Moreover, the PaCO2 difference observed between CV5 and SV5 (4.4 +/- 4.1 mmHg) was significantly greater than that observed between CV10 and SV10 (2.5 2.4 mmHg) (P = 0.014). CONCLUSIONS: The elimination of apparatus dead space to improve CO2 removal can be more beneficial in a ventilation mode with 5 ml/kg of tidal volume, and a frequency of 20/min rather than in 10 ml/kg of tidal volume, and a frequency of 10/min.
Extremities ; Humans ; Tidal Volume ; Ventilation*

With low-flow oxygen administration, one of the methods of oxygen therapy, the concentration of oxygen depends on the flow rate and on the tidal volume of the patient. It is often casually referred to as 100% oxygen, though in fact it is usually 30-60%, and rarely exceeds 70%. A patient who receiving 6l/min of oxygen flow by nasal cannula is receiving an FiO2 of 44%, nasal cannula with more than 6l flow does little to increase inspired oxygen concentrations. Patients in control group received 0.11/min/kg of oxygen flow by modified T-piece in PAR,in low flow group received 0.11/min/kg of oxygen flow and in high group received 0.2Vmin/kg of oxygen flow. Blood pressure,heart rate, ABGA, SaO2, PAR score were measured in PAR with 5 minutes interval. PaO2 and SaO2 of low flow group were significantly (p<0.05) lower than control group with 5 of PAR score, PaO2 of low flow group was significantly (p<0.05) lower than control group with 10 of PAR score and PaO2 and SaO2 of high flow group were significantly (p<0.05) higher than low flow group with 10 of PAR score. These result suggest that patient who were taken Ravitch's operation receive a higher oxygen flow than others who were taken operation except Ravitch's operation for the same effect of oxygen therapy.
Catheters ; Humans ; Oxygen* ; Tidal Volume

In the volume-cycled ventilator, the actual tidal volume delivered to the patient is influenced by the compression volume and elasticity of the circuit. The purpose of the present study is to compare the set tidal volume with the measured tidal volume, and calculate the compression factor of the ventilator. We studied twenty pediatric patients weighting above 10 kg. The set tidal volume ( V(r)), the exhaled volume displayed in the ventilator ( V(exh)) and the actual tidal volume measured by the Wright spirometer ( V(sp)) were compared. The results were as follows: 1) Mean tidal volume was 248+/-92 ml, mean exhaled volume was 233+/-102 ml and mean spirometer volume was 19+/-97 ml. Thus the set and the measured tidal volume were different significantly (p<0.05). but we may calculate the actual tidal volume by the relationship with the set tidal volume ( Vsp-1.03V(T) - 56 ) 2) Mean compression factor was 1.35+/-0.92 ml/cmH2O.
Adult* ; Elasticity ; Humans ; Tidal Volume* ; Ventilators, Mechanical*

BACKGROUND: The aim of this study was to determine whether the end-tidal concentration of desflurane would be affected by a breathing circuit system filter attached at two different positions in anesthetic breathing circuit systems. METHODS: An artificial lung was ventilated under five different conditions. The first group was without any filter or desflurane (n = 5, sham), the second was with desflurane but without any filter (n = 10, control), the third group had a bacterial filter on the expiratory limb (n = 10), and the fourth and fifth groups had a viral/bacterial filter added on the expiratory limb (n = 10) or at the Y-piece of the breathing circuit (n = 10), respectively. In all groups except the sham, administration of 10% desflurane was performed for 5 minutes and then stopped for 5 minutes. RESULTS: The mean (SD) end-tidal concentration of desflurane for the groups described above peaked at 0 (0), 9.8 (0.1), 9.8 (0.1), 8.5 (0.1), and 6.7% (0.1) (P < 0.001), respectively. There was no difference in the desflurane concentrations and the expired tidal volume over time between the control and bacterial group, but there was a significant difference between the control and the fourth and fifth groups (P < 0.001). CONCLUSIONS: Filters can affect the expiratory desflurane concentration during anesthesia.
Anesthesia ; Extremities ; Lung ; Respiration ; Tidal Volume

This paper describes to design and to examine the mechanical characteristics of high frequency jet ventilator. The device consists of Phase lock loop (PLL) system, solenoid valve driving control part and Air regulating system. This study is carried out by changing several factors such as endotracheal tube (E.T. tube) diameter, injector cannula diameter, 1%, and frequency (breaths/min.) having direct effects on the gas exchange as well as parameters of the entrained gas by venturi effect, so as to measure the tidal volume and minute volume. This system characteristics were as follows: 1) Frequency: 6-594 bpm 2) Inspiration time: 1-99% 3) Variance of input air pressure: 1-30 PSI
Air Pressure ; Catheters ; Tidal Volume ; Ventilators, Mechanical*

Anesthesia machine is an important equipment of clinical surgery. This paper introduces several abnormal conditions of the anesthesia machine, especially the judgment and the common fault check of the tidal volume for reference.
Anesthesia ; methods ; Anesthesiology ; instrumentation ; Humans ; Tidal Volume

No abstract available.
Carbon Dioxide* ; Carbon* ; Respiratory Rate* ; Tidal Volume*

Respiratory effects of acute coronary embolism were studied in mongrel dogs. Coronary embolism was produced by Agress's method and respirtory effects were observed for two hours. In the experimental group, in which coronary embolism was produced, there were relative decreases in respiratory rate and arterial oxygen saturation along with relative increases in tidal volume, minute ventilation, ventilation equivalent and arteriovenous oxygen difference compared to those in the control group. However, differences in these various measurements between tow groups, those in tidal volume and arterial oxygen saturation, have greatly diminished in two hours. These facts suggest that changes in respiratory rate, minute ventilation, ventilation equivalent and arteriovenous oxygen difference in the experimental group are early but short-lasting responses to acute coronary embolism, whereas changes in tidal volume and arterial oxygen saturation occur early and last longer.
Animals ; Dogs ; Embolism* ; Oxygen ; Respiratory Rate ; Tidal Volume ; Ventilation

Plasma CO2 gas tension, tidal volume and peak inspiratory airway pressure were investigated before CO2gas insufflation, 30 minutes and 60 minutes after gas insufflation in 32 laparoscopic surgery patients to study the effects of intraabdominal CO2 gas insufflation during laparoscopic surgery under general endotracheal anesthesia with controlled ventilation. Our results were as follows 1) Arterial CO2 gas tension values were significantly higher 30 minutes after CO2 gas insufflation compared to before gas insufflation(36.8+/-4.2 mmHg vs. 28.3+/-6.8 mmHg). 2) Tidal volume was increased 30 minutes after CO2 gas insufflation compared to before gas insufflation(505.1+/-78.2 ml vs. 462.0+/-83.2 ml). 3) Peak inspiratory airway pressure was significantly increased 30 minutes after CO2 gas insufflation compared to before gas insufflation(16.4+/-1.7 cmH2O vs. 9.8+/-1.0 cmH2O). And these increasing states were maintained during laparoscopic surgery. As the above results show, during laparoscopic surgery using CO2 gas insufflation under general anesthesia with controlled ventilation, arterial CO2 gas tension, tidal volume and peak inspiratory airway pressure were significantly increased 30 minutes after CO2 gas insufflation. Cautions may be advised if laparoscopic surgery, by whatever operation, is indicated in subjects who are affected by increasing PaCO2 and peak inspiratory airway pressure.
Anesthesia ; Anesthesia, General* ; Humans ; Insufflation* ; Laparoscopy* ; Plasma ; Tidal Volume* ; Ventilation