An observational study to find out changes in arterial oxygen tension during fiberoptic bronchoscopy

Background:Arterialhypoxaemiaisthecommonestcomplication,sincerespiratory depressantdrugsareusedforpremedication,andtheairwayisalsopartially occludedbythebronchoscope.Thestudyisthereforedesignedtofindoutthechangesinarterialoxygen tensionduring (FOB)alongwitheffectoncentral hemodynamics, pre andpost procedure ECGand PFT.Objectives were tofind out thechanges in arterial oxygentension during FOB, to study the effects of FOBon central hemodynamics, electrocardiographicallyand pulmonaryfunction tests.Methods:One hundred patients aged above 20 years undergoing FOB were evaluated for the arterial oxygen tension and cardiac rhythm changes at KNCH, Jodhpur during 12 months study period from 2019 to 2020.Results:All patients developed a fall in PaO2following FOB but hypoxaemia was noted only in 18 cases. Bronchial washing, punch biopsy and brush biopsy did contribute to hypoxaemia significantly. There was a uniform rise in heart rate in all the patients after FOB which was statistically significant. There was slight sinus tachycardia inmostofthecases although ECG indicated no major arrhythmias.ThepulmonaryfunctionswhichincludechangeinVC,FVC, FEV1andPEFR after FOB, on statisticallycomparisonnostatistical difference could be observed. Therewasnosignificantchangein PaCO2level and pH level.MeanofSBP andmeanofDBPwasstatistically significant.Conclusions:All patients showed a decline in arterial PaO2after FOB which was highly significant. There was slight sinus tachycardia in most of cases. FOB itself does not endanger the patients with any significant or serious complications.

Effect of nasal continuous positive airway pressure and Bi-phase positive airway pressure on oxygen exchange indexes in newborns with mild to moderate neonatal respiratory distress syndrome / 中华实用儿科临床杂志

Objective To observe the effect of nasal continuous positive airway pressure (nCPAP) and Biphase positive airway pressure (BIPAP) on the oxygen exchange indexes in newborns with mild to moderate neonatal respiratory distress syndrome (NRDS).Methods After infusion of pulmonary suffactant into lung bilaterally,116 cases with mild to moderate NRDS were treated with nCPAP(nCPAP group,n =75) and BIPAP(BIPAP group,n =41) respectively.Oxygen exchange indexes including arterial partial pressure of oxygen [pa (O2)],modified oxygenation index (P/F),alveolar-arterial oxygen tension difference (A-aDO2),respiratory index (RI),artery/alveolar oxygen partial pressure ratio[pa (O2)/pA (O2)] and pulmonary shunt fraction (Qs/Qt) were measured or calculated at 0 (before treatment),2,8 and 24 h after being treated with nCPAP or BIPAP.Results Six different oxygen exchange indexes of Pa (O2),P/F,A-aDO2,RI,pa (O2)/pA(O2) and Qs/Qt in both groups didn't show statistical significance at 0 hour:pa(O2) (kPa) (6.1 ±0.6 vs 6.1 ±0.6,t =0.11,P ＞0.05),P/F(kPa) (15.59 ± 1.45 vs 15.71 ± 1.45,t =1.59,P ＞ 0.05),A-aDO2(kPa)(6.04 ±0.64 vs 6.24 ±0.69,t =1.59,P ＞0.05),RI(6.0 ± 1.0 vs 6.2 ± 1.1,t =1.35,P ＞ 0.05),p,(O2)/pA(O2) (0.24 ±0.02 vs 0.25 ±0.03,t =1.63,P ＞0.05)and Qs/Qt(％)(11.9±1.6 vs 11.6 ± 1.6,t =1.10,P ＞ 0.05).A-aDO2,RI,pa (O2)/pA (O2) and Qs/Qt of BIPAP group had more improvement than those of nCPAP at 2 and 24 h,and oxygen exchange indexes at 2 h of BIPAP group and those of nCPAP group were:A-aDO2 (kPa) (3.83 ±0.49 vs 4.24 ± 0.67,t =18.26,P ＜ 0.05),RI(2.7 ± 0.5 vs 3.3 ±0.7,t =20.59,P ＜ 0.05),p,(O2)/pA(O2) (0.35 ±0.03 vs 0.32 ±0.04,t =15.35,P ＜0.05) and Qs/Qt(％) (8.8 ± 1.6 vs 9.8 ±2.0,t =7.68,P ＜ 0.05) ; 24 h indexes in BIPAP group and the indexes of nCPAP group were:A-aDO2 (kPa) (2.29 ± 1.19 vs 3.07 ± 1.67,t=18.43,P ＜0.05),RI(1.4 ±1.4 vs 2.3 ± 1.6,t=25.02,P ＜0.05),pa(O2)/pA(O2) (0.49 ±0.10 vs 0.42 ±0.11,t =14.96,P ＜0.05) and Qs/Qt(％) (6.5 ±3.0 vs 8.5 ±4.4,t =9.59,P ＜0.05).pa(O2) and P/F of both groups didn't show statistical difference significantly [Pa (O2)(kPa) (12.6 ± 1.0 vs 12.7 ± 1.0,t =3.76,P ＞ 0.05),P/F(28.49 ± 3.17 vs 31.85 ± 2.85,t =3.76.P ＞ 0.05)].Nineteen cases in nCPAP group needed invasive mechanical ventilation,and only 3 cases in BIPAP group underwent the procedure;there was a significant difference (x2 =4.01,P ＜ 0.05).Oxygen exchange indexes in both groups were gradually improved from 2 h,8 h to 24 h,but 22 deteriorated cases showed no improvement,who underwent invasive ventilation.Positive end-expiratory pressure (PEEP) positive airway pressure (EPAP) was (0.42 ± 0.19) kPa in BIPAP group,and (0.56 ± 0.23) kPa in nCPAP group (t =3.45,P ＜ 0.01).Conclusions 1.BIPAP and nCPAP can improve the ability of oxygen exchange in newborns with mild to moderate NRDS,but BIPAP is more effective than nCPAP,which can shorten the possibility of invasive ventilation and reduce the PEEP level.2.p,(O2),P/F,pa (O2)/pA (O2) and RI may be more suitable for evaluating oxygen exchange for neonatal NRDS.

Effects of Difference in Arterial Oxygen Tension on Ischemia/Reperfusion Injury of Spinal Cord in Rabbits / 대한마취과학회지

BACKGROUND: In the milieu of the postischemic nerve system, oxygen plays an important, but different role on the ischemia/reperfusion injury. Oxygen is needed in newly restored oxidative phosphorylation to reenergize neurons depleted of ATP and membrane potential. Alternatively, oxygen may also be used as substrate for the destructive free radical-mediated processes that seem to be common final pathways in numerous mechanisms of ischemia/reperfusion injury. Several investigators have reported decreasing inspired oxygen concentration was neuroprotective. But, others have demonstrated hyperbaric oxygen was useful for reducing the ischemia/reperfusion injury. Our study aims first to evaluate the effects of difference in arterial oxygen tension on early phase of ischemia/reperfusion injury and to outline practical use of oxygen to reduce ischemic/reperfusion injury. METHODS: A rabbit spinal cord ischemia model of infrarenal aortic occlusion for 17 mins was employed. Rabbits were randomly assigned to three groups. The rabbits in control group (n = 3) did not undergo ischemic insult. The rabbits in group A (n = 5) and B (n = 5) underwent ischemic insult for 17 mins and then breathed oxygen (6 L/min) via facial mask or room air, respectively. We observed neurologic function for 2 days. The sections of the spinal cords were stained with hematoxylin and eosin, and the number of spinal motor neurons in ventral region was counted by light microscopy. RESULTS: All rabbits in control group did not have neurologic dysfunction whereas all rabbits in group A and B had neurologic dysfunction at same degree. Spinal motor neurons in ventral gray matter in group A and B decreased significantly compared with those in control group (P < 0.05). But, difference in number between group A and B was not significant. CONCLUSIONS: The result indicated that the level of arterial oxygen tension within the clinical range had little effect on early phase of ischemia/reperfusion injury.

Effects of Desflurane and Isoflurane on Arterial Oxygenation and Hemodynamics during One-lung Ventilation / 대한마취과학회지

BACKGROUND: Potent inhalational agents are widely used for thoracic anesthesia. They have several desirable properties, including ease of administration, rapid onset and offset, and bronchodilation. One potential drawback is their ability to directly inhibit hypoxic pulmonary vasoconstriction. Desflurane does not directly inhibit hypoxic pulmonary asoconstriction in vivo, in contrast to isoflurane using the same animal model. In this study, we compared the effects of desflurane and isoflurane on arterial oxygenation and hemodynamics during one lung ventilation in a humans. METHODS: Thirty five patients scheduled for coronary artery bypass graft were randomly assigned to one of group D/I and I/D. Group D/I consisted of four steps. Hemodynamics and oxygenation parameters were checked in each step. Step 1 was checked when they received desflurane to an end tidal concentration of 6% in 93% oxygen from induction until the end of 30 min of two lung ventilation. Step 2 was checked at the end of 30 min after starting one lung ventilation. Step 3 was checked at the end of 30 min after receiving isoflurane to an end tidal concentration of 1.2% in 93% oxygen during one lung ventilation. Step 4 was checked at the end of 30 min after restarting two lung ventilation. Group I/D received the two anesthetic agents in reverse order. We used the simple cross-over design methodology for treatment and period effect. RESULTS: We found no significant difference in hemodynamic and oxygenation parameters between the two inhalational agents except for a significant increase in mean pulmonary arterial pressure and pulmonary capillary wedge pressure caused by desflurane. CONCLUSIONS: During one lung ventilation, the choice between desflurane and isoflurane does not significantly influence arterial oxygenation and shunt fraction but desflurane should be administered with great caution if it is used as an alternative anesthetic in patients with ischemic heart disease.

The Effect of Positioning with Mechanically Ventilatory Acute Respitatory Failure Patients on Arterial Oxygen Partial Pressure and Alveolar-arterial Oxygen tension / 성인간호학회지

It is widely recognized that manipulation of body position takes advantage of the influences of gravity for improving oxygenation. The study aims to determine the effects of positioning(supine, prone, right lateral decubitus and left lateral decubitus positions) applied to the mechanically ventilatory acute respiratory failure patients on arterial oxygen partial pressure(PaO2), alveolar arterial oxygen tension difference(AaDO2), mean aterial pressure, peak inspiratory pressure and plateau pressure. Thirty two acute respiratory failure patients admitted to the medical intensive care unit at Kangnam St. Mary's Hospital, The Catholic University of Korea from March 1997 to January 1998, were divided into three groups by radiographic evidence of unilateral or bilateral lung disease. In group 1 with dominant right lung disease were twelve subjects, group 2 with dominant left lung disease had eight subjects and group 3 had twelve subjects with bilateral lung disease. The variables were measured in 30 minutes after each position of supine, prone, good lung down lateral decubitus and sick lung down lateral decubitus position. The position order was done at random by Latin squre design. The results are as follows; 1) With group 1 patients, the PaO2 in the left lateral decubitus and prone position were 126.8+/-30.8 mmHg and 106.7+/-36.8 mmHg, respectively(p=0.0001). 2) With group 2 patients, the PaO2 in the prone and the right lateral decubitus position were 121.7+/-44.7 mmHg and 118.5+/-31.7 mmHg, respectively (p=0.0018). 3) With group 3 patients, the PaO2 was 143.6+/-36.6 mmHg in the prone position (p=0.0001). 4) With group 1 patients, the AaDO2 in the left lateral decubitus and the right lateral decubitus position were 178.1+/-29.7 mmHg and 233.1+/-24.4 mmHg, respectively(p=0.0001). 5) With group 2 patients, the AaDO2 in the prone and the left lateral decubitus postion were 184.0+/-39.5 mmHg and 231.0+/-23.9 mmHg, respectively(p=0.0019). 6) With group 3 patients, the AaDO2 in the prone and the supine postion were 377.1+/-35.6 mmHg and 435.7+/-13.1 mmHg, respectively (p=0.0001). 7) There were no differences among the mean arterial pressure, peak inspiratory pressure and plateau pressure for each of the supine, prone, left lateral decubitus and right lateral decubitus position. The results suggest that oxygenation may improve in mechanically ventilatory patients with unilateral lung disease when the position is good lung dependent and prone, and patients with bilateral lung disease when the position is prone without any effects on the mean arterial pressure and airway pressure. It is suggested that body positions improve ventilation/perfusion matching and oxygenation need to be specified in patient care plans.

Effect of Changes in Fraction of Inspired Oxygen(F1O2) on Pulmonary Shunt Ratio in Respiratory Intensive Care / 대한마취과학회지

For the purpose of recommending appropriate fraction of inspired oxygen(F1O2) for long term mechanical ventilation support by evaluating the effect of changes in F1O2 on pulmonary shunt ratio in respiratory intensive care, the effects of various F1O2 on pulmonary shunt ratio were investigated and analysed with 20 pediatric intensive care patients who had received open heart surgeries for their congenital heart diseases in the department of Pediatrics, Seoul National University Hospital. The results were as follows ; 1. Through the whole process of control of mechanical ventilation the arterial CO2 tension(PaCO2) showed hyperventilation with the average of 31-34mmHg and pH showed pure respiratory alkalosis with the average of 7.45-7.51. As the fraction of inspired oxygen decreased, the arterial oxygen tension decreased. 2. Inspite of the change of F1O2, analysis of central venous blood gas showed no significant change. 3. The alveolar-arterial oxygen tension difference(AaDO2) was positively related to F1O2. 4. The pulmonary shunt ratio(Q's/Q'T) showed no significant difference in the F1O2 range of 0.6 to 1.0. But the Q's/Q'T in the F1O2 range of 0.3 to 0.4 decreased significantly comparing to that of 0.6 to 1.0 F1O2 range. Linear regression analysis of Q's/Q'T showed that the Q's/Q'T was positively related to F1O2 and AaDO2, respectively.

Arterial Oxygen Tension Measurements during Nitrous Oxide - Oxygen Anesthesia / 대한마취과학회지

In 30 ASA class I patients aged 15-30 undergoing peripheral operations, PaO2 and SaO2 were determined while the mixture of nitrous oxide and oxygen was administered at the inspired oxygen concentration of 21%. Anesthesia was maintained with 75% or so nitrous oxide and small dose fentanyl, and ventilation was adjusted to maintain normoventilation with tidal volume increased to 15 ml/kg. PaO2 and SaO2 during anesthesia were increased significantly when compared to those which were measured immediately prior to anesthetic induction, that is to say, no one developed hypoxemia despite administration of the same inspired oxygen concentration as that of room air. These results indicate that, in case rapid emergence from anesthesia is required, balanced anesthesia with high concentration nitrous oxide and small dose fentanyl should be very useful and safe so long as we make good selections of patients and deliver large tidal volumes to them during artificial ventilation.

The Changes in Arterial Oxygen Tension ( PaO2 ) after Application of Selective Continuous Positive Airway Pressure ( CPAP ) to Nondenpendent Lung during One - Lung Ventilation / 대한마취과학회지

Anesthesia for thoracic surgery is most commonly performed with the patient in the lateral decubitus position, with nondependent hemithorax comprising the operation field. When one-lung ventilation is employed, the nondependent lung is nonventilated and collapsed, while the dependent lung is ventilated. Consequently one-lung ventilation creates an obligatory right to left transpulmonary shunt through the nondependent nonventilated lung. Therefore one-lung ventilation results in a much larger alveolar-arterial oxygen tension-difference P(A-a)O2 and lower PaO2 than does two-lung ventilation. The present study was to evaluate oxygenation effect of selective CPAP to nondependent lung in the 17 thoracic surgical patients. Arterial blood gases were analysed, systolic blood pressures and heart rates were measured at following stages. Stage I; lateral decubitus position before chest opening Stage II; 15 min after chest opening and one lung ventilation stage III; 15 min after application of selective CPAP 5 cmHO to the nondependent lung stage IV; 40 min after application of selective CPAP 5 cmHO to the nondependent lung The results were as follows: 1) In stage II, the value of PaO2 was significantly lower as compared to that in stage I(224.9+/-78.0 vs 418.2+/-63.1 mmHg, P<0.01). 2) In stage III and IV, the values of PaC4 were significantly higher.as compared to that in stage II(333.8+/-97.1, 364.5+/-88.6 vs 224,9+/-78.0 mmHg, P<0.01). 3) In stage III, the value of PaCO2 was significantly lower as compared to that in stage II(37.1+/-2.9 vs 38.2+/-2.7 mmHg, P<0.05). 4) In stage IV, the value of pH was significantly lower as compared to that in stage III(7.37+/-0.05 vs 7.38+/-0.05 P<0.05). 5) Systolic blood pressures and heart rates remained unchanged at all times. We concluded that application of 5 cmHO CPAP to the nondependent lung during one-lung ventilation is one of most efficacious maneuvers to increase PaO2, accompanying less surgical interference.

Effect of Extreme Leukocytosis on Arterial Oxygen Tension / 대한마취과학회지

Arterial blood gas analysis has become an integral part of the clinical evaluation of the patient with known or suspected pulmonary disease. However, when the results of the measurements show arterial hypoxemia which is out of proportion to the clinical and X-ray evidence of lung disease, we may consider potential errors in measurement involving the blood gas analyzer or methods of blood sample storage. We experienced spurious hypoxemia in a patient with extreme leukocytosis (220.0 X 10(3)/mm3) secondary to leukemia. The degree of PaO2 decay was blunted by placing the blood on ice.

Acute Respiratory Failure following Anesthesia / 대한마취과학회지

We define acute respiratory failure(ARF) as present whenever the ratio of arterial oxygen tension (PaO2) and inspired oxygen concentrarion(FiO2) is below the normal predicted range for the patient's age and/or the arterial carbon dioxide tension(PaCO2) is above 45 in the absence of respiratory compention for metabolic alkalosis. Adult respiratory distress syndrome(ARDS) which is associated with shock, trauma, infection, inhalation of toxic gas, aspiration of gastric content and drugs etc, first received wide-spread attention in 1967. ARDS is a descriptive term that is characterized by a combination of refractory hypoxemia and severly decreased lung compliance. Numerous specific incidents or illnesses may be complicated by, or associated with ARDS. Early diagnosis and improvement in physiological therapy including PEEP therapy have been successful in treating the early and mild episodes of ARDS. This report describes three cases of ARF following anesthesia and reviews the literature.