Transcutaneous oxygen tension and ankle brachial pressure index as predictors of outcome in diabetic foot

Background: Diabetic foot ulcer poses a serious threat to patients with Diabetes as the presence of an ulcer further significantly increases the risk of an amputation. Aim and Objectives: The present study was undertaken to assess: Correlation of transcutaneous oxygen tension (TcpO2) and ankle brachial pressure index (ABI) in outcome of diabetic foot and severity of neuropathy by grades. Materials and Methods: About 30 patients of Type 2 Diabetes Mellitus with foot lesions and 30 healthy controls were selected after obtaining informed consent and ethical committee clearance. Subjects were recruited taking into consideration various inclusion and exclusion criteria. The subjects were assessed for the following parameters: Vibration perception, hot, and cold perception along with TcpO2 and ankle brachial pressure index (ABI). The test results were compared within the two groups of cases, that is, Group I: Healed ulcer and Group II-Non-healed ulcer. The results of the two groups were compared with 30 healthy controls also. Results: Males were predominant (66.67%) compared to females (33.33%) in the diabetic foot patients. Severe derangements in the sensory modalities were found as observed by the bilaterally reduced values of vibration perception, hot perception and cold perception tests when diabetic foot patients were compared to controls. The values, however, were not significantly different between the two groups of patients of diabetic foot. The values of TcPO2 and ABI were bilaterally reduced in the cases as compared to controls and amongst the Group I and Group II comparison these values showed a significant difference. A highly significant positive correlation was observed between the TcPO2 and ABI test results in the diabetic foot patients that indicates both are complimentary tests for diabetic foot outcome prediction. Conclusion: Increased duration of diabetes, high value of Hba1c and presence of neuropathy were found to be important risk predictors for diabetic foot. Early and severe derangement of vibration perception indicated early involvement of large nerve fibers. Heat and cold perception is affected late and less severely, indicating late involvement of small nerve fibers in diabetic polyneuropathy. The positive correlation between TcPO2 and ABI indicates both are complementary tests for predicting the outcome of diabetic foot. However, TcPO2 being a better predictor maybe incorporated as a routine screening test for diabetic foot risk and outcome predictor in the diabetic foot clinic.

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.

Cambios morfológicos, proteicos, glicoproteicos y antigénicos de Trypanosoma cruzi cultivado en medio axénico con tensiones de oxígeno diferentes / Morphological, protein, glycoprotein and antigenic changes of Trypanosoma cruzi cultured in axenic medium with different oxygen tensions

Se ha reportado cultivo axénico de amastigotas de Trypanosoma cruzi derivados de epimastigotas. Se cuestiona si formas redondas en cultivos axénicos son verdaderos amastigotas. Aquí se compararon los cambios biológicos y moleculares de epimastigotas creciendo en alta y baja tensión de oxígeno. T. cruzi (EPm6) se creció en frascos con diferentes alturas de medio LITB (condición horizontal 3 mm y vertical 83 mm). Se colectaron masas de parásitos de diferentes tiempos de crecimiento para análisis proteico, glicoproteico y antigénico. Se estudiaron los cambios morfológicos, incremento de inóculo y resistencia al complemento por microscopia de fases y tinción con Giemsa. Los cambios proteicos y glicoproteicos se compararon por SDS-PAGE. Los cambios antigénicos se analizaron por Western blot con suero de conejo y anticuerpos IgY contra formas amastigotas. En condición vertical, los epimastigotas mantuvieron su morfología típica a lo largo de la curva de crecimiento y no mostraron cambios moleculares significativos. En condición horizontal al 4to y 6to día predominaron formas redondas con capacidad de resistir la lisis por complemento. A partir del 4to día se observaron cambios en los perfiles proteicos y glicoproteicos, concomitantemente con los cambios morfológicos. El suero anti-amastigotas reveló un antígeno amastigota-específico transitorio de 55 kDa en parásitos de 4 días en la condición horizontal, mientras el anticuerpo IgY anti-amastigotas no reveló diferencias entre parásitos creciendo en ambas condiciones. Estas evidencias sugieren que epimastigotas de T. cruzi condicionados a sobrevivir en alta tensión de oxígeno puede mimetizar propiedades biológicas y antigénicas propias del estadio amastigota.

Axenic culture of epimastigote-derived amastigotes of Trypanosoma cruzi has been reported. Have been inquired why round forms appear in culture media and if are true amastigotes. Our proposal was study molecular and biological changes in epimastigotes growing in high and low oxygen tension. T. cruzi (EPm6) were grown in flasks with different height of LITB medium (horizontal condition 3 mm and vertical 83 mm). Parasites were collected masses of different times of growth for proteins, glycoproteins and antigenic analysis. Morphological changes, increase of inoculum and resistance to complement lyses were studied in phase’s microscopy and Giemsa-stained smears. Protein and glycoprotein changes were compared by SDS-PAGE. Antigenic changes were analyzed by Western blot with rabbit serum and IgY antibody against amastigote forms. In vertical condition, the epimastigote maintained its typical morphology along the growth curve and not showed significant molecular changes. In horizontal condition round forms prevailed at 4 and 6 days with capacity to resist lyses by complement. From the 4th day changes in proteins and glycoproteins profiles were observed, concomitantly with the morphological changes. Anti-amastigotes serum revealed a 55 kDa transitory amastigote-specific antigen in four day parasites’ from horizontal condition, while IgY antibody anti-amastigotes don’t revealed differences between parasites grown in both conditions. These evidences suggest that epimastigotes of T. cruzi conditioned to survive in high oxygen tension can mimic biological and antigenic properties own the amastigote-stage.

Study on the safety and effectiveness of an exercise prescription for patients with diabetic foot ulcer and peripheral arterial disease / 中华内分泌代谢杂志

Objective To investigate the effect of exercise prescription on foot perfusion and ulcer healing in patients with diabetic foot ulcer (DFU) accompanied with peripheral arterial disease (PAD).Methods Sixty patients with DFU and PAD were divided into exercise group and control group.The patients in the exercise group took exercise therapy training,ensuring that they could follow the exercise prescription.The patients in the control group had no exercise requirements.After the treatment for 12 weeks,ankle brachial index (ABI),transcutaneous oxygen tension (TcPO2),skin temperature,body mass index (BMI),HbA1C,and the ulcer healing rate in the two groups were compared,the satisfaction and compliance in the exercise group were evaluated,and the adverse events of the treatment were recorded.Results After the treatment for 12 weeks,the ABI,TcPO2,and foot skin temperature in the two groups increased and HbA1C decreased(P＜0.05 or P＜0.01).TcPO2 increased 5.25 mm Hg(1 mm Hg=0.133kPa),skin temperature increased 0.45℃,and BMI decreased 0.69 kg/m2 in the exercise group,while TcPO2 increased 2.59 mm Hg,skin temperature increased 0.28℃,and BMI increased 0.02 kg/m2 in the control group,showing significant differences in the three index changes between two groups (P＜0.01).The healing rate in the exercise group was higher than that in the control group (53.6％ vs 25.9％,P ＜0.05).The patients'compliance and satisfaction to the exercise therapy were 90％ and 94％,respectively.The incidence of adverse events in the exercise group had no causal relationship with the exercise prescription.Conclusion The exercise prescription in the study can improve the foot perfusion,and promote ulcer healing.It has the advantage of high safety,patients'compliance and satisfaction.

Effect of arterial oxygen tension during reperfusion on myocardial recovery in patients undergoing valvular heart surgery / 대한마취과학회지

BACKGROUND: Valvular heart surgery (VHS) utilizing cardiopulmonary bypass (CPB) is inevitably associated with ischemic-reperfusion injury, which is known to depend on oxygen tension during reperfusion. The aim of this study was to evaluate the effect of arterial oxygen tension during reperfusion on myocardial recovery in patients undergoing VHS. METHODS: Fifty-six patients undergoing isolated VHS were randomly exposed to an oxygen fraction of 0.7 (hyperoxic group, n = 28) or 0.5 (normoxic group, n = 28) during reperfusion. All patients received an oxygen fraction of 0.7 during CPB. In the normoxic group, the oxygen fraction was lowered to 0.5 from the last warm cardioplegia administration to 1 minute after aortic unclamping, and was then raised back to 0.7. Hemodynamic data were measured after induction of anesthesia, weaning from CPB, and sternum closure. The frequency of cardiotonic medications used during and after weaning from CPB, and the short-term outcomes during the hospital stay were also assessed. RESULTS: The frequency of vasopressin and milrinone use during weaning from CPB, but not norepinephrine, was significantly less in the normoxic group. The post-operative cardiac enzyme levels and short-term outcomes were not different between the groups. CONCLUSIONS: Normoxic reperfusion from the last cardioplegia administration to 1 minute after aortic unclamping in patients undergoing VHS resulted in significantly less frequent use of vasopressin and inotropics during weaning from CPB than hyperoxic reperfusion, although it did not affect the post-operative myocardial enzyme release or short-term prognosis.

Blood flow control in the brain: possible biphasic mechanism of functional hyperemia.

Background: About 120 years ago, Roy and Sherrington hypothesized that the cerebral blood flow (CBF) is closely coupled to metabolism, and metabolism is closely coupled to function. This concept has colored all subsequent inquiries. However, recent studies have revealed a temporal and spatial mismatch between changes in CBF and metabolism. Objective: This article aims to reappraise the nature of functional hyperemia in response to somatosensory stimuli. Method: Firstly, the author discusses what is known and unknown about the control of CBF, reviewing the traditional concepts of autoregulation, neurogenic control, metabolic control and the role of endothelial cells. Secondly, recent papers showing a mismatch or uncoupling between function, metabolism and flow are considered. Thirdly, the reviewer uses his own published and unpublished data to point out the intrinsic and largely unrecognized limitations of spectroscopic techniques for evaluation of oxygen metabolism. Finally, a novel hypothesis is presented concerning the nature of functional hyperemia. Results and conclusion: The reviewer deduces that the initial flow increase in functional hyperemia is elicited by central neural systems, since it is reported that the central cholinergic pathway increases CBF immediately after the onset of somatosensory stimuli. The flow increase occurs concurrently with neuronal activation, but is much faster than the increase of neuronal metabolism. The novel hypothesis is proposed that functional hyperemia is biphasic: an initial flow increase under central neural control and a delayed increase is under traditional metabolic control. The metabolic phase may supply more blood than is needed, and may last even after discontinuation of the stimulation (overcompensation). These two phases of hyperemia are suggested to be well mixed, presumably in glial processes, which coordinate blood redistribution in the surrounding microvascular network. Many stimuli from the environment might be managed simply by the neurogenic control of functional hyperemia, without the metabolic change.

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.

Does Propofol Improve Postischemic Myocardial Dysfunction by Reducing the Postischemic Adhesion of Polymorphonuclear Neutrophils? / 대한마취과학회지

BACKGROUND: Fluid replacement after hemorrhage usually results in hemodilution, and hemodilution leads to increased cerebral blood flow, which is known to be beneficial to the outcome of ischemic brain damage. However, the effect of hemodilution may be different in patients with head injuries and increased intracranial pressure (ICP). The aim of this study was to evaluate the effects of normovolemic hemodilution on cerebral blood flow (CBF), brain tissue oxygen tension (PbtO2), and the severity of cryogenic brain injury, and to determine the acceptable limit of hemodilution during cryogenic brain injury. METHODS: Thirty New Zealand white rabbits were anesthetized with O2-N2O-isoflurane. Cryogenic brain injury (1 cm in diameter) was produced by applying liquid nitrogen on the surface of the right parietal bone for 90 seconds. Sixty minutes after cryogenic brain injury, acute normovolemic hemodilution was induced with 10% pentastarch for 30 minutes. In group I (n = 7), hemodilution was not induced. In groups II (n = 7), III (n = 8), and IV (n = 8), the hemoglobin concentrations were adjusted to 9-10, 6-7 and 3-4 g/dl, respectively. Mean arterial pressure, central venous pressure and ICP were measured, and local CBF and PbtO2 of the right parietal subcortex were continuously monitored. The rabbits were euthanized 150 minutes after brain injury, and the brains were removed and sectioned coronally through the center of the lesion. The extent of brain injury in the coronal plane was measured by light microscopic examination. The posterior part of the brain was divided into two halves and the water fraction of each part was measured by the dry-weight method. Data obtained were compared by the Kruskal-Wallis test or by repeated measures ANOVA. The difference was considered significant when P <0.05. RESULTS: No differences were observed in mean arterial pressure, central venous pressure or rectal temperature. However, significant differences were found in ICP, CBF and PbtO2 among the groups. ICP was significantly higher in group IV than in groups I and II. The CBF values of groups III and IV were higher than those of group I. The values of PbtO2 of group IV were lower than those of groups I and II. Normovolemic hemodilution, of up to 6-7 g/dl of hemoglobin, led to an abrupt increase in CBF and a subsequent increase in ICP. Hemodilution, of up to 3-4 g/dl of hemoglobin, decreased brain tissue oxygen tension significantly. No differences in the brain water fractions and the extent of cryogenic injury were found among the groups. CONCLUSIONS: It is concluded that the acceptable limit of acute normovolemic hemodilution in cryogenic brain injury is 9-10 g/dl of hemoglobin, as ICP and CBF do not increase and PbtO2 does not deteriorate.

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 Effects of High Frequency Jet Ventilation to the Collapsed Lung on Systemic Oxygenation during One Lung Ventilation / 대한마취과학회지

BACKGROUND: In some cases of one-lung ventilation (OLV), hypoxemia may occur secondarily to the obligatory right to left transpulmonary shunt through the collapsed lung. We investigated the efficacy of high frequency jet ventilation (HFJV) to the non-dependent lung which rendered to be manually collapsed by surgeon and not to be reinflated, in improving systemic oxygenation and ventilation during OLV while ventilating the dependent lung with intermittent positive pressure ventilation. METHODS: Investigation was carried out on 20 ASA 2 or 3 patients who underwent thoracotomy in lateral decubitus position. The patients were randomly allocated into HFJV group (n = 11) or CPAP group (n = 9). In HFJV group, 20 minutes after OLV began, HFJV with driving pressure 1.0 bar, Ti 30%, and frequency 150 cycles/min, was applied to the non-dependent lung. In CPAP group, 5 cmH2O of CPAP was applied to the non-dependent lung without re-inflation. We compared the changes of PaO2, PaCO2, AaDO2 and pulmonary shunt, before and after HFJV or CPAP was applied to the non-dependent lung during OLV. RESULTS: AaDO2 and pulmonary shunt were decreased significantly and therefore, PaO2 was increased significantly when HFJV was applied to the non-dependent lung (P < 0.05, respectively). PaO2, AaDO2 and pulmonary shunt were not improved after 5 cmH2O of CPAP was applied to the non-dependent lung without re-inflation. In HFJV group, PaCO2 measured after HFJV was not decreased significantly compared with that before HFJV. CONCLUSIONS: HFJV to the non-dependent lung during OLV improved systemic oxygenation, even after the non-dependent lung collapsed completely but did not enhance CO2 elimination. 5 cmH2O of CPAP to the non-dependent lung, which was completely collapsed and not re-inflated, did not improve systemic oxygenation.

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 High Frequency Jet Ventilation alone or with Positive End Expiratory Pressure on the Arterial Oxygenation during One Lung Ventilation / 대한마취과학회지

BACKGROUND: Hypoxemia during one lung ventilation (OLV) may occur in spite of high inspired oxygen concentration. The purpose of this study was to evaluate the effect of highfrequency jet ventilation (HFJV) alone to the non-ventilated lung or in combination with 5 cmH2O of positive end expiratory pressure (PEEP) to the ventilated lung on arterial oxygenation (PaO2) during OLV for thoracic surgery. METHODS: After endotracheal intubation with double lumen tube, arterial blood gases were measured 20 minutes after stabilization had occurred following onset of OLV, HFJV, and HFJV with 5 cmH2O of PEEP. RESULT: The mean PaO2 during OLV was 257.5+/-81.7 mmHg, and application of HFJV alone or with PEEP resulted in a significant increase in PaO2 to 356.6+/-79.1 mmHg and 354.9+/-66.6 mmHg, respectively (p<0.001). Alveolar-arterial oxygen differences were significantly decreased as compared to OLV. CONCLUSION: Both HFJV alone or in combination with 5cmH2O of PEEP are effective to improve oxygenation during OLV.

The Comparison of the Effect of Enflurane and Propofol on Arterial Oxygenation during One-Lung Ventilation / 대한마취과학회지

BACKGROUND: Controversy exists as to whether or not inhalation anesthetics and intravenous anesthetics impair arterial oxygenation (PaO2) during one lung ventilation (OLV). Accordingly, we examined the effect of enflurane and propofol on PaO2 and pulmonary vascular resistance (PVR) during OLV. METHODS: Forty patients, who had prolonged periods of OLV anesthesia with minimal trauma to the nonventilated lung were studied in a cross over design. Patients were randomized to four groups; Group 1 received 1 MAC of enflurane and oxygen from induction until the first 20 min after complete lung collapse, then were switched to propofol 100 g/kg/min (P100). In group 2, the order of the anesthetics was reversed. Group 3, Group 4 received the same order of the anesthetics as Group 1, Group 2, respectively but received propofol 200 g/kg/min (P200). RESULTS: During OLV, the PaO2 values were lower than those with two lung ventilation (TLV), there were no significant differences among each groups and between propofol and enflurane in PaO2, but in the selected patients (n=10, PaO2<120 mmHg during OLV), PaO2 in propofol group was higher than that of enflurane group (p<0.05). Conversion from TLV to OLV caused a significant increase in PVR, but there were no difference in PVR between propofol and enflurane group. CONCLUSIONS: These results suggest that the usual clinical dose of propofol affords no advantage over 1 MAC of enflurane anesthesia except low PaO2 patients during OLV. Propofol might be of value in risk patients of hypoxemia during thoracic surgery when OLV is planned.

Comparison of Gas Exchange Indices after Open Heart Surgery / 대한마취과학회지

BACKGROUND: The objectives of the study were to determine how gas exchanges indices including alveolar-arterial oxygen tension difference(A-aDO2), PaO2/PAO2, PaO2/FIO2 and pulmonary shunt ratio (QS/QT) were changed after open heart surgery according to the change of inspired fraction of oxygen(FIO2) and to identify the reliable parameters for postoperative respiratory care in the intensive care unit. METHODS: Blood gases were measured from radial and pulmonary arterial blood for arterial and mixed venous blood in 15 patients, with a mean age of 45.1 yr, after open heart surgery, in mechanically ventilated states with 1.0, 0.6 and 0.4 of FIO2 with normocarbia maintained (PaCO2 30~40 mmHg). Above mentioned gas exchange indices were calculated and compared. RESULTS: After decreasing the FIO2 from 1.0 to 0.6 and 0.4 in order, the major changes were significant decrease in pulmonary shunt ratio : 24+/-3%, 17+/-3% and 11+/-3% at FIO2 1.0, 0.6 and 0.4, respectively and A-aDO2 : 347+/-34 mmHg, 184+/-16 mmHg and 94+/-11 mmHg at FIO2 1.0, 0.6 and 0.4 respectively, while PaO2/PAO2 showed the only significant increase at FIO2 0.4 compared with those at FIO2 1.0 and PaO2/FIO2 was unchanged. CONCLUSIONS: In cases of open heart surgical patient with cardiovascular stability, pulmonary shunt ratio and A-aDO2 appear to be more sensitive on gas exchange, but the oxygen tension indices such as PaO2/PAO2 as well as PaO2/FIO2 might be suggested as possible alternatives for the shunt measurement.

Is There Any Difference in Arterial Oxygenation between the Right and Left Thoracic Surgery under the Different One Lung Ventilation Mode? / 대한마취과학회지

BACKGROUND: Use of one lung anesthesia for thoracic surgery may compromize PaO2. The aim of this study was to compare the shunt and oxygenation effects of the application of CPAP and CPAP/PEEP between right and left thoracic surgery under one lung anesthesia. METHODS: 10 patients for right thoracic surgery were selected as group 1, and 10 patients for left thoracic surgery were selected as group 2. Measurements in each group, were made during each of the following stage. First 30 minutes, One lung anesthesia alone with 50% oxygen (control value), next 30 minutes, CPAP 10 cmH2O to upper lung with 50% oxygen (CPAP), and then CPAP 10 cmH2O to upper lung and PEEP 10 cmH2O to down lung with 50% oxygen for 30 minutes (CPAP/PEEP). RESULTS: PaO2 in CPAP and CPAP/PEEP were significantly increased as compare to control value at both group (P<0.05). Shunt percentage in CPAP and CPAP/PEEP were significantly decreased as compare to control value at both group (P<0.05). But, no statistically significant differences were observed between right and left thoracic surgery group in the PaO2 and shunt percentage. CONCLUSIONS: We confirmed that CPAP and CPAP/PEEP during one lung ventilation is thought to be effective method in preventing hypoxemia, but no differences were observed between right and left thoracic surgery group.

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 Effect of Dissolved Oxygen Tension on the Fermentation of D-ribose / 微生物学通报

After comparing the varieties of parameters in batch culture under different dissolved oxygen tension by Bacillus pumilus, we found that the demand of cell on oxygen in different phase isn' t consistent. Based on the analys is of the metabolic pathway of oxygen and the mechanism of the effect of dissolved oxygen tension on fermentation of D-ribose, a two-stage oxygen-supply control mode was proposed and experimentally proved to be available. High ribose yield and high glucose consumption rate were achieved during whole process for 44h, and the ultimate ribose concentration and cell concentration were 5.0% and 18.8% higher than former respectively.

Influence of Changes in Mixed Venous Oxygen Tension(PvO2) by Extracorporeal Membrane Oxygenation(ECMO) on Hypoxic Pulmonary Vasoconstriction / 대한마취과학회지

Blood flow generally decreases to areas of the lung that become hypoxie, thereby reducing pulmonary shunt and preventing arterial hypoxemia. The mechanism of blood flow reduction in the hypoxic area is believed to be hypoxic pulmonary vasoconstriction(HPV). Over the years, serious attention has been given to the question of whether hypoxia of the airway(alveolar hypoxia) is the only way to elicit pulmonary vasoconstriction. the current consensus favors this traditional view. Even though the usual experiments have succeeded in proving that a large drop in alveolar PO2(PAO2) does elicit pulmonary vasoconstriction, they have not excluded the possibility that a sufficient drop in mixed venous PO(PvO2) may have the same eonsequenee. The purpose of this study is to test the hypothesis that a decrease in PvO2 may elicit hypoxic pulmonary vasoconstriction. For the selective change of PvOwe used venovenous extracorporeal circulation(VVECMO), a technique which had been tested for adequacy in hemodynamics and oxygenation in preliminary studies on 6 mongrel dogs. In eight pentobarbital-anesthetized, mechanically ventilated mongrel dogs, stepwise reductions in oxygen concentration(F1O2,) from 0.21 to 0.15 and 0.10 caused remarkable HPV. The mean pulmonary arterial pressure(MPAP) and the pulmonary vascular resistance(PVR) were increased from 17.3+/-3 mmHg and 185+/-64 dyne sec cm(-5) in normoxia(F1O2=0.21) to 30+/-6 mmHg and 401+/-257 dyne sec cm in severe hypoxia(F1O2=0.10, P(A)O2=30+/-9 mmHg), respectively ; while, in moderate hypoxia(F1OP2=0.15, P(A)O2=53+/-12 mmHg), only the MPAP increased and the increase was from 17.3+/-3 mmHg to 23+/-3 mmHg. The selective increase in PvO2without any change in P(A)O2 by extracorporeal veno-venous bypass from 37+/-6 mmHg and 22+/-4 mmHg to 54+/-8 mmHg and 45+/-5 mnHg in moderate and severe hypoxia, respectively, depressed HPV: decrease in MPAP in moderate hypoxia(MPAP=21+/-4 mmHg) and decrease in MPAP and PVR in severe hypoxia(MPAP=23+/-5 mmHg, PVR=319+/-228 dyne sec * cm(-5)). This study indicates that the mixed venous oxygen tension is an important determinant of the magnitude of hypoxic pulmonary vasoconstriction in diffuse alveolar hypoxia. Moreover, the method used in this study and the result might be useful other pulmonary pathophysiological studies and clinical situations with acute diffuse alveolar hypoxia, such as acute respiratory failure and chronic obstructive pulmonary diseases.