1
|
Yoon S, Kim BR, Min SH, Lee J, Bahk JH, Seo JH. Repeated intermittent hypoxic stimuli to operative lung reduce hypoxemia during subsequent one-lung ventilation for thoracoscopic surgery: A randomized controlled trial. PLoS One 2021; 16:e0249880. [PMID: 33857201 PMCID: PMC8049270 DOI: 10.1371/journal.pone.0249880] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 03/23/2021] [Indexed: 11/18/2022] Open
Abstract
Background An intervention to potentiate hypoxic pulmonary vasoconstriction may reduce intrapulmonary shunt and hypoxemia during one-lung ventilation. Previous animal studies reported that repeated intermittent hypoxic stimuli potentiated hypoxic pulmonary vasoconstriction, but no clinical study has examined the effects of this intervention on hypoxemia during one-lung ventilation. We thus performed a single-center, parallel-group, double-blind, randomized controlled trial to investigate whether repeated intermittent hypoxic stimuli to the operative lung reduce hypoxemia during the subsequent one-lung ventilation for thoracoscopic surgery. Methods Patients undergoing one-lung ventilation were randomized into two groups (n = 68 each). Before one-lung ventilation, in the intermittent hypoxia group, the nondependent lung was not ventilated for 2 min and then ventilated for 2 min while the dependent lung was continuously ventilated. This was repeated five times. In the continuous normoxia group, both lungs were ventilated for 20 min. We measured SpO2, PaO2, FiO2, PaCO2, SaO2, and central venous oxygen saturation during one-lung ventilation. The primary outcome was the number of patients with hypoxemia defined as a SpO2 <95% during one-lung ventilation, which was analyzed with a chi-squared test. Results Hypoxemia was less frequent in the intermittent hypoxia group than in the continuous normoxia group during OLV [6/68 (8.8%) vs 17/68 (25.0%), risk ratio (95% CI) 0.35 (0.15–0.84), p = 0.012]. The PaO2 (p = 0.008 for 30 min and 0.007 for 60 min) and PaO2/FiO2 (p = 0.008 for both) were higher 30 and 60 min after starting one-lung ventilation, and the alveolar-arterial pressure gradient (p = 0.010) and shunt index (p = 0.008) were lower 30 min after starting one-lung ventilation in the intermittent hypoxia group than in the continuous normoxia group. Postoperative adverse events did not differ significantly between groups. Conclusions Repeated intermittent hypoxic stimuli to the operative lung seemed to potentiate hypoxic pulmonary vasoconstriction, and thus reduced hypoxemia during the subsequent one-lung ventilation.
Collapse
Affiliation(s)
- Susie Yoon
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Bo Rim Kim
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Se-Hee Min
- Department of Anesthesiology and Pain Medicine, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Jaehun Lee
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jae-Hyon Bahk
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jeong-Hwa Seo
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea
| |
Collapse
|
2
|
Abstract
It has been known for more than 60 years, and suspected for over 100, that alveolar hypoxia causes pulmonary vasoconstriction by means of mechanisms local to the lung. For the last 20 years, it has been clear that the essential sensor, transduction, and effector mechanisms responsible for hypoxic pulmonary vasoconstriction (HPV) reside in the pulmonary arterial smooth muscle cell. The main focus of this review is the cellular and molecular work performed to clarify these intrinsic mechanisms and to determine how they are facilitated and inhibited by the extrinsic influences of other cells. Because the interaction of intrinsic and extrinsic mechanisms is likely to shape expression of HPV in vivo, we relate results obtained in cells to HPV in more intact preparations, such as intact and isolated lungs and isolated pulmonary vessels. Finally, we evaluate evidence regarding the contribution of HPV to the physiological and pathophysiological processes involved in the transition from fetal to neonatal life, pulmonary gas exchange, high-altitude pulmonary edema, and pulmonary hypertension. Although understanding of HPV has advanced significantly, major areas of ignorance and uncertainty await resolution.
Collapse
Affiliation(s)
- J. T. Sylvester
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Larissa A. Shimoda
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Philip I. Aaronson
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Jeremy P. T. Ward
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| |
Collapse
|
3
|
Abstract
All cells respond to metabolic stress. However, a variety of specialized cells, commonly referred to as O2-sensing cells, are acutely sensitive to relatively small changes in PO2. Within a variety of organisms such O2-sensing cells have evolved as vital homeostatic mechanisms that monitor O2 supply and alter respiratory and circulatory function, as well as the capacity of the blood to transport O2. Thereby, arterial PO2 may be maintained within physiological limits. In mammals, for example, two key tissues that contribute to this process are the pulmonary arteries and the carotid bodies. Constriction of pulmonary arteries by hypoxia optimizes ventilation-perfusion matching in the lung, whilst carotid body excitation by hypoxia initiates corrective changes in breathing patterns via increased sensory afferent discharge to the brain stem. Despite extensive investigation, the precise mechanism(s) by which hypoxia mediates these responses has remained elusive. It is clear, however, that hypoxia inhibits mitochondrial function in O2-sensing cells over a range of PO2 that has no such effect on other cell types. This raised the possibility that AMP-activated protein kinase might function to couple mitochondrial oxidative phosphorylation to Ca2+ signalling mechanisms in O2-sensing cells and thereby underpin pulmonary artery constriction and carotid body excitation by hypoxia. Our recent investigations have provided significant evidence in support of this view.
Collapse
Affiliation(s)
- A Mark Evans
- Division of Biomedical Sciences, School of Biology, Bute Building, University of St Andrews, St Andrews, Fife KY16 9TS, UK.
| |
Collapse
|
4
|
Leach RM, Hill HS, Snetkov VA, Ward JPT. Hypoxia, energy state and pulmonary vasomotor tone. Respir Physiol Neurobiol 2002; 132:55-67. [PMID: 12126695 DOI: 10.1016/s1569-9048(02)00049-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Vasomotor responses to hypoxia constitute a fundamental adaptation to a commonly encountered stress. It has long been suspected that changes in cellular energetics may modulate both hypoxic systemic artery vasodilatation (HSV) and hypoxic pulmonary artery vasoconstriction (HPV). Although limitation of energy has been shown to underlie hypoxic relaxation in some smooth muscles, the response to hypoxia in vascular smooth muscle does not appear to be a simple function of energy stores, but instead may involve perturbations of ATP or energy delivery to mechanisms controlling muscle force, and/or changes associated with anaerobic metabolism. Recent work in pulmonary vascular smooth muscle has demonstrated that energy stores are maintained during hypoxic pulmonary vasoconstriction, and that this is dependent on glucose availability and up-regulation of glycolysis. There is increasing evidence that glycolysis is preferentially coupled to a variety of membrane associated ATP dependent processes, including the Na(+) pump, Ca(2+)-ATPase, and possibly some protein kinases. These and other mechanisms may influence excitation-contraction coupling in both systemic and pulmonary arteries by effects on intracellular Ca(2+) and/or Ca(2+) sensitivity. Hypoxia has also been postulated to have major effects on other cytosolic second messenger systems including phosphatidylinositol pathways, cell redox state and mitochondrial reactive oxygen species production. This review examines the relationship between energy state, anaerobic respiration and hypoxic vasomotor tone, with a particular emphasis on hypoxic pulmonary vasoconstriction.
Collapse
Affiliation(s)
- Richard M Leach
- Department of Respiratory Medicine and Allergy, Centre for Cardiovascular Biology and Medicine, Guy's, King's and St Thomas' School of Medicine, King's College London, Guy's Campus, London SE1 9RT, UK.
| | | | | | | |
Collapse
|
5
|
Yuan XJ, Sugiyama T, Goldman WF, Rubin LJ, Blaustein MP. A mitochondrial uncoupler increases KCa currents but decreases KV currents in pulmonary artery myocytes. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 270:C321-31. [PMID: 8772460 DOI: 10.1152/ajpcell.1996.270.1.c321] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Intracellular free Ca2+ concentration ([Ca2+]i) and ATP play important roles in the regulation of K- channels in pulmonary artery (PA) myocytes. Previous studies have demonstrated that hypoxia and the metabolic inhibitor, 2-deoxy-D-glucose, decrease voltage-gated K+ (KV) currents [IK(V)] and thereby depolarize PA myocytes; these effects lead to a rise in [Ca2+]i. Here, we used carbonyl cyanide p-trifluoromethoxyphenyl-hydrazone (FCCP), a protonophore that uncouples mitochondrial respiration from ATP production, to test whether the inhibition of oxidative phosphorylation affects K+ channel activities in rat PA myocytes. Patch-clamp and fluorescent-imaging microscopy techniques were used to measure K+ currents (IK) and [Ca2+]i, respectively. FCCP (3-5 microM) reversibly raised [Ca2-]i in the presence and absence of external Ca2+. This effect was prevented by pretreating the cells with the membrane-permeable Ca2+ chelator, 1,2-bis(2-amino-phenoxy) ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA-AM). This suggests that much of the FCCP-evoked rise in [Ca2-]i was due to Ca2+ release from intracellular stores. Brief exposure to FCCP (approximately 2 min) reversibly enhanced Ik. This augmentation was not influenced by glibenclamide, an ATP-sensitive K channel blocker, but was eliminated by pretreatment with BAPTA-AM. This implies that the FCCP-evoked rise in [Ca2+]i activated Ca(2+)-activated K- (Kca) channels. Furthermore, in BAPTA-treated cells, longer application (> or = 6 min) of FCCP reversibly decreased IK(V) in PA cells bathed in Ca(2+)-free solution. These results demonstrate that FCCP affects KCa and Kv channels by different mechanisms. FCCP increases IK[Ca] by raising [Ca2+]i primarily as a result of Ca2+ release, but decreases IK(V) by a Ca(2+)-independent mechanism, presumably the inhibition of oxidative ATP production.
Collapse
Affiliation(s)
- X J Yuan
- Department of Medicine, University of Maryland School of Medicine, Baltimore, USA
| | | | | | | | | |
Collapse
|
6
|
Zhao Y, Packer CS, Rhoades RA. The vein utilizes different sources of energy than the artery during pulmonary hypoxic vasoconstriction. Exp Lung Res 1996; 22:51-63. [PMID: 8838135 DOI: 10.3109/01902149609074017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Recent studies have shown that the contractile response to hypoxia is much greater in the pulmonary vein than in the artery. The purpose of this study was to investigate the effects of substrate utilization and oxidative phosphorylation on the responses of the pulmonary vein and artery to acute hypoxia. Isolated rat pulmonary arterial and venous rings were placed in tissue baths containing Earle's balanced salt solution (37 degrees C, 95% O2/5% CO2, pH 7.4), and attached to force transducers. The vascular rings were equilibrated for 1 h and then contracted maximally with 80 mM KCl to establish maximum active tension development (Po). Following washout and complete relaxation, the rings were incubated with the following substrates or metabolic inhibitors for 30-40 min: varying concentrations of glucose (0, 5.5, 10, or 20 mM), or glycolytic intermediates (4 mM pyruvate or 4 mM lactate), or inhibitors of glycolysis (50 mM 2-deoxyglucose or 0.1 mM iodoacetate), or an inhibitor of oxidative phosphorylation (0.1 microM rotenone). Vascular rings were then made hypoxic by lowering the bath Po2 to 30 torr. The pulmonary vein responded with a single contraction while the artery responded biphasically as previously reported. The pulmonary venous hypoxic response was not affected by the absence of glucose but was inhibited by high glucose concentrations. Neither glucose metabolic intermediates (pyruvate or lactate) nor the glycolysis inhibitor 2-deoxyglucose had any effect on the pulmonary venous response to hypoxia. However, inhibition of oxidative phosphorylation by rotenone inhibited the venous hypoxic response. In contrast, the pulmonary arterial phase 1 contraction to hypoxia was inhibited and phase 2 contraction was abolished in glucose-free solution. This effect was not due to the decreased production of glucose metabolic intermediates, since addition of pyruvate or lactate did not reverse the decreased arterial hypoxic response in glucose-free solution. Increasing the glucose concentration did not affect phase 1 contraction, but 20 mM glucose inhibited the phase 2 contraction. Inhibition of glycolysis with 2-deoxyglucose or iodoacetate decreased phase 1 contraction and abolished the phase 2 contraction. Inhibition of oxidative ATP production with rotenone abolished phase 1 but not phase 2 contraction. In conclusion, (1) the pulmonary venous response to hypoxia is unaffected by inhibition of glycolysis but is inhibited by high glucose and by inhibition of oxidative ATP production; (2) the pulmonary arterial hypoxic phase 1 contraction is dependent on oxidative ATP production; and (3) the phase 2 contraction of the pulmonary arterial hypoxic response depends on glycolytic ATP production but not on oxidative ATP production. These results indicate that the pulmonary vein and artery preferentially utilize different sources of energy for hypoxic contractions.
Collapse
Affiliation(s)
- Y Zhao
- Department of Physiology and Biophysics, Indiana University School of Medicine, Indianapolis 46202-5120, USA
| | | | | |
Collapse
|
7
|
Weissmann N, Grimminger F, Walmrath D, Seeger W. Hypoxic vasoconstriction in buffer-perfused rabbit lungs. RESPIRATION PHYSIOLOGY 1995; 100:159-69. [PMID: 7624617 DOI: 10.1016/0034-5687(94)00133-k] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Isolated rabbit lungs were buffer-perfused under constant flow-conditions with separate control of alveolar (PAO2) and mixed venous (PvO2) O2 tension. Alveolar hypoxia caused an increase in pulmonary artery pressure (PAP) with sigmoidal dose-dependency. Erythrocytes increased the strength of the hypoxic pulmonary vasoconstriction (HPV). The contractile and vasorelaxant responses to the onset and release of alveolar hypoxia, respectively, occurred within seconds. Kinetics of the PAP increase, but not the magnitude of response, were related to the velocity of PAO2 decline. In contrast, changes in PvO2, both in the absence and presence of erythrocytes, did neither provoke any pressor response nor amplify the response to concomitant alveolar hypoxia. Repeatedly performed HPV manoeuvres revealed excellent reproducibility, and long-term alveolar hypoxia (90 min) provoked a biphasic pressor response. We conclude that the isolated rabbit lung is a feasible model for the characterization of hypoxic vasoconstriction, with specific features hitherto not described for perfused lungs of other species.
Collapse
Affiliation(s)
- N Weissmann
- Department of Internal Medicine, Justus-Liebig-University, Giessen, Germany
| | | | | | | |
Collapse
|
8
|
Albarwani S, Robertson BE, Nye PC, Kozlowski RZ. Biophysical properties of Ca(2+)- and Mg-ATP-activated K+ channels in pulmonary arterial smooth muscle cells isolated from the rat. Pflugers Arch 1994; 428:446-54. [PMID: 7838666 DOI: 10.1007/bf00374564] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A novel class of Ca(2+)-activated K+ channel, also activated by Mg-ATP, exists in the main pulmonary artery of the rat. In view of the sensitivity of these "KCa,ATP" channels to such charged intermediates it is possible that they may be involved in regulating cellular responses to hypoxia. However, their electrophysiological profile is at present unknown. We have therefore characterised the sensitivity of KCa,ATP channels to voltage, intracellular Ca2+ ([Ca2+]i) and Mg-ATP. They have a conductance of 245 pS in symmetrical K+ and are approximately 20 times more selective for K+ ions than Na+ ions, with a K+ permeability (PK) of 4.6 x 10(-13) cm s-1.Ca2+ ions applied to the intracellular membrane surface of KCa,ATP channels causes a marked enhancement of their activity. This activation is probably the result of simultaneous binding of at least two Ca2+ ions, determined using Hill analysis, to the channel or some closely associated protein. This results in a shift of the voltage activation threshold to more hyperpolarized membrane potentials. The activation of KCa,ATP channels by Mg-ATP has an EC50 of approximately 50 microM. Although the EC50 is unaffected by [Ca2+]i, channel activation by Mg-ATP is enhanced by increasing [Ca2+]i. One possible interpretation of these data is that Mg-ATP increases the sensitivity of KCa,ATP channels to Ca2+. It is therefore possible that under hypoxic conditions, where lower levels of Mg-ATP may be encountered, the sensitivity of KCa,ATP channels to Ca2+ and therefore voltage is reduced.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- S Albarwani
- University Laboratory of Physiology, Oxford, UK
| | | | | | | |
Collapse
|
9
|
Hasséssian H, Bodin P, Burnstock G. Blockade by glibenclamide of the flow-evoked endothelial release of ATP that contributes to vasodilatation in the pulmonary vascular bed of the rat. Br J Pharmacol 1993; 109:466-72. [PMID: 8358546 PMCID: PMC2175668 DOI: 10.1111/j.1476-5381.1993.tb13592.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
1. The effect of step augmentation of flow rate on the level of adenosine -5'-triphosphate (ATP) measured in the Krebs perfusate was investigated, and the effect of glibenclamide on the release of ATP was tested in the rat pulmonary vascular bed. 2. For flow rates between 10.38 +/- 1.18 and 28.88 +/- 2.08 ml min-1 (n = 8) 1 microM suramin, a P2-purinoceptor antagonist, significantly (P < 0.05) increased vascular resistance under conditions of step augmentation of flow rate. This suggests that endogenous ATP released during increases in flow rate dilates pulmonary vessels. 3. In response to a step augmentation in flow rate from 9.13 +/- 0.97 to 18.3 +/- 1.69 ml min-1 (n = 4) ATP levels were up to 23 fold higher (P < 0.05) for 15 s, and gradually dropped to a level of about half the initial rise. Once the ATP levels had stabilized, another step augmentation of flow rate to 27.00 +/- 3.49 ml min-1 was able to evoke a corresponding increase of ATP release. The ability of the vascular bed to respond with increased ATP release after the initial ATP responses had tapered, demonstrates that the drop in ATP levels after the initial rise is not due to depletion of ATP. Furthermore, the maximal ATP response directly precedes the vasodilatation observed following each jump in perfusion pressure produced with each step increase in flow rate. 4. In response to two 3 fold step augmentations of flow rate (8.41-27.29 ml min-1) spaced 30 min apart there were two increases in the level of ATP which were not significantly different from each other.However, perfusion with 1 microM glibenclamide between the first and the second step augmentation of flow rate (8.08-24.67 ml min-1) significantly (P<0.05; n = 6) blocked the increase in ATP release. This suggests that the release of intracellular ATP is mediated by glibenclamide-sensitive K+ channels.5. A concentration of 1 microM glibenclamide perfused for 30 min was without effect on vascular pressure at constant flow. However, under conditions where flow was augmented in a stepwise manner (between 11.50 and 36.45 ml min-1) perfusing with 1 microM glibenclamide increased vascular resistance (P <0.10).6. It is concluded that flow-induced ATP release is mediated by a glibenclamide-sensitive K+ channel,and that the release of ATP from endothelial cells probably functions to vasodilate the pulmonary vascular bed of the rat.
Collapse
Affiliation(s)
- H Hasséssian
- Department of Anatomy and Developmental Biology, University College London
| | | | | |
Collapse
|
10
|
Marrone O, Bellia V, Pieri D, Salvaggio A, Bonsignore G. Acute effects of oxygen administration on transmural pulmonary artery pressure in obstructive sleep apnea. Chest 1992; 101:1023-7. [PMID: 1555416 DOI: 10.1378/chest.101.4.1023] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In order to investigate the role of hypoxia on the cyclic oscillation of transmural pulmonary artery pressure (PAP) in obstructive sleep apnea, oxygen was administered during one half of the night to six patients affected by obstructive sleep apnea syndrome during a nocturnal polysomnographic study. In each patient, transmural PAP measurements were performed on 15 randomly selected apneas recorded while breathing room air, and on 15 during O2 administration. During O2 administration in all patients, apneas were associated with a higher oxyhemoglobin saturation (SaO2), a smaller SaO2 swing, and a higher transcutaneous PCO2. The mean highest level of transmural PAP in the apneic episodes, commonly reached at their end, was significantly lower than while breathing room air in only two patients; however, due to a decrease in the mean lowest PAP level (at the beginning of apneas), the extent of the PAP increase within apneas did not differ between air and O2 breathing; these patients showed the smallest increase in transcutaneous PCO2 in our sample. End-apneic transmural PAP during O2 administration was significantly higher in one subject (for systolic values) and was not significantly different in the remaining three subjects. The extent of the increase in transmural PAP within apneas was greater in one patient; it was smaller in another one, but only for the diastolic values; and it did not differ significantly with respect to the value observed while breathing room air in all of the other subjects. The results suggest that hypoxia in obstructive apneas, at least in some patients, may lead to a steady increase in PAP, detectable both at the beginning and at the end of the episodes; conversely, the increase in PAP within apneas does not seem to be influenced by the simultaneous decrease in SaO2.
Collapse
Affiliation(s)
- O Marrone
- Istituto di Fisiopatologia Respiratoria del CNR, Palermo, Italy
| | | | | | | | | |
Collapse
|