| 1. |
- Olegård, Cecilia, 1967, et al.
(författare)
-
Estimation of functional residual capacity at the bedside using standard monitoring equipment: a modified nitrogen washout/washin technique requiring a small change of the inspired oxygen fraction.
- 2005
-
Ingår i: Anesthesia and analgesia. - 0003-2999. ; 101:1
-
Tidskriftsartikel (refereegranskat)abstract
- We developed a modified nitrogen washin/washout technique based on standard monitors using inspiratory and end-tidal gas concentration values for functional residual capacity (FRC) measurements in patients with acute respiratory failure (ARF). For validation we used an oxygen-consuming lung model ventilated with an inspiratory oxygen fraction (Fio(2)) between 0.3 and 1.0. The respiratory quotient of the lung model was varied between 0.7 and 1.0. Measurements were performed changing Fio(2) with fractions of 0.1, 0.2, and 0.3. In 28 patients with ARF, duplicate measurements were performed. In the lung model, an Fio(2) change of 0.1 resulted in a value of 103 +/- 5% of the reference FRC value of the lung model, and the precision was equally good up to an Fio(2) of 1.0 with a value of 103 +/- 7%. In the patients, duplicate measurements showed a bias of -5 mL with a 95% confidence interval [-38; 29 mL ]. A comparison of a change in Fio(2) of 0.1 with 0.3 showed a bias of -9 mL and limits of agreement of [-365; 347 mL]. This study shows good precision of FRC measurements with standard monitors using a change in Fio(2) of only 0.1. Measurements can be performed with equal precision up to an Fio(2) of 1.0.
|
|
| 2. |
- Sand Bown, Lena, et al.
(författare)
-
Vasopressin-induced changes in splanchnic blood flow and hepatic and portal venous pressures in liver resection.
- 2016
-
Ingår i: Acta anaesthesiologica Scandinavica. - : Wiley. - 1399-6576 .- 0001-5172. ; 60:5, s. 607-615
-
Tidskriftsartikel (refereegranskat)abstract
- To minimize blood loss during hepatic surgery, various methods are used to reduce pressure and flow within the hepato-splanchnic circulation. In this study, the effect of low- to moderate doses of vasopressin, a potent splanchnic vasoconstrictor, on changes in portal and hepatic venous pressures and splanchnic and hepato-splanchnic blood flows were assessed in elective liver resection surgery.
|
|
| 3. |
- Berger, D., et al.
(författare)
-
Effect of PEEP, blood volume, and inspiratory hold maneuvers on venous return
- 2016
-
Ingår i: American Journal of Physiology. Heart and Circulatory Physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 311:3
-
Tidskriftsartikel (refereegranskat)abstract
- According to Guyton’s model of circulation, mean systemic filling pressure (MSFP), right atrial pressure (RAP), and resistance to venous return (RVR) determine venous return. MSFP has been estimated from inspiratory hold-induced changes in RAP and blood flow. We studied the effect of positive end-expiratory pressure (PEEP) and blood volume on venous return and MSFP in pigs. MSFP was measured by balloon occlusion of the right atrium (MSFPRAO), and the MSFP obtained via extrapolation of pressure-flow relationships with airway occlusion (MSFPinsp_hold) was extrapolated from RAP/pulmonary artery flow (QPA) relationships during inspiratory holds at PEEP 5 and 10 cmH2O, after bleeding, and in hypervolemia. MSFPRAO increased with PEEP [PEEP 5, 12.9 (SD 2.5) mmHg; PEEP 10, 14.0 (SD 2.6) mmHg, P = 0.002] without change in QPA [2.75 (SD 0.43) vs. 2.56 (SD 0.45) l/min, P = 0.094]. MSFPRAO decreased after bleeding and increased in hypervolemia [10.8 (SD 2.2) and 16.4 (SD 3.0) mmHg, respectively, P < 0.001], with parallel changes in QPA. Neither PEEP nor volume state altered RVR (P = 0.489). MSFPinsp_hold overestimated MSFPRAO [16.5 (SD 5.8) vs. 13.6 (SD 3.2) mmHg, P = 0.001; mean difference 3.0 (SD 5.1) mmHg]. Inspiratory holds shifted the RAP/QPA relationship rightward in euvolemia because inferior vena cava flow (QIVC) recovered early after an inspiratory hold nadir. The QIVC nadir was lowest after bleeding [36% (SD 24%) of preinspiratory hold at 15 cmH2O inspiratory pressure], and the QIVC recovery was most complete at the lowest inspiratory pressures independent of volume state [range from 80% (SD 7%) after bleeding to 103% (SD 8%) at PEEP 10 cmH2O of QIVC before inspiratory hold]. The QIVC recovery thus defends venous return, possibly via hepatosplanchnic vascular waterfall. © 2016 the American Physiological Society.
|
|
| 4. |
- Choncholas, Gary, et al.
(författare)
-
Validation and clinical application of a first order step response equation for nitrogen clearance during FRC measurement.
- 2008
-
Ingår i: Journal of clinical monitoring and computing. - : Springer Science and Business Media LLC. - 1387-1307 .- 1573-2614. ; 22:1, s. 1-9
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To derive a difference equation based on mass conservation and on alveolar tidal volumes for the calculation of Functional Residual Capacity. Derive an equation for the FRC from the difference equation. Furthermore, to derive and validate a step response equation as a solution of the difference equation within the framework of digital signal processing where the FRC is known a priori. METHODS: A difference equation for the calculation of Functional Residual Capacity is derived and solved as step response of a first order system. The step response equation calculates endtidal fractions of nitrogen during multiple breath nitrogen clearance. The step response equation contains the eigenvalue defined as the ratio of FRC to the sum of FRC and alveolar tidal ventilation. Agreement of calculated nitrogen fractions with measured fractions is demonstrated with data from a metabolic lung model, measurements from patients in positive pressure ventilation and volunteers breathing spontaneously. Examples of eigenvalue are given and compared between diseased and healthy lungs and between ventilatory settings. RESULTS: Comparison of calculated and measured fractions of endtidal nitrogen demonstrates a high degree of agreement in terms of regression and bias and limits of agreement (precision) in Bland & Altman analysis. Examples illustrate the use of the eigenvalue as a possible discriminator between disease states. CONCLUSION: The first order step response equation reliably calculates endtidal fractions of nitrogen during washout based on a Functional Residual Capacity. The eigenvalue may be a clinically valuable index alone or in conjunction with other indices in the analysis of respiratory states and may aid in the setting of the ventilator.
|
|
| 5. |
- Fagerberg, Anneli, 1964, et al.
(författare)
-
Electrical impedance tomography and heterogeneity of pulmonary perfusion and ventilation in porcine acute lung injury.
- 2009
-
Ingår i: Acta anaesthesiologica Scandinavica. - : Wiley. - 1399-6576 .- 0001-5172. ; 53:10, s. 1300-9
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The heterogeneity of pulmonary ventilation (V), perfusion (Q) and V/Q matching impairs gas exchange in an acute lung injury (ALI). This study investigated the feasibility of electrical impedance tomography (EIT) to assess the V/Q distribution and matching during an endotoxinaemic ALI in pigs. METHODS: Mechanically ventilated, anaesthetised pigs (n=11, weight 30-36 kg) were studied during an infusion of endotoxin for 150 min. Impedance changes related to ventilation (Z(V)) and perfusion (Z(Q)) were monitored globally and bilaterally in four regions of interest (ROIs) of the EIT image. The distribution and ratio of Z(V) and Z(Q) were assessed. The alveolar-arterial oxygen difference, venous admixture, fractional alveolar dead space and functional residual capacity (FRC) were recorded, together with global and regional lung compliances and haemodynamic parameters. Values are mean+/-standard deviation (SD) and regression coefficients. RESULTS: Endotoxinaemia increased the heterogeneity of Z(Q) but not Z(V). Lung compliance progressively decreased with a ventral redistribution of Z(V). A concomitant dorsal redistribution of Z(Q) resulted in mismatch of global (from Z(V)/Z(Q) 1.1+/-0.1 to 0.83+/-0.3) and notably dorsal (from Z(V)/Z(Q) 0.86+/-0.4 to 0.51+/-0.3) V and Q. Changes in global Z(V)/Z(Q) correlated with changes in the alveolar-arterial oxygen difference (r(2)=0.65, P<0.05), venous admixture (r(2)=0.66, P<0.05) and fractional alveolar dead space (r(2)=0.61, P<0.05). Decreased end-expiratory Z(V) correlated with decreased FRC (r(2)=0.74, P<0.05). CONCLUSIONS: EIT can be used to assess the heterogeneity of regional pulmonary ventilation and perfusion and V/Q matching during endotoxinaemic ALI, identifying pivotal pathophysiological changes.
|
|
| 6. |
- Kiss, Katalin, et al.
(författare)
-
Mannitol clearance for the determination of glomerular filtration rate-a validation against clearance of Cr-51-EDTA
- 2018
-
Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961. ; 38:1, s. 10-16
-
Tidskriftsartikel (refereegranskat)abstract
- We studied the agreement between plasma clearance of mannitol and the reference method, plasma clearance of Cr-51-EDTA in outpatients with normal to moderately impaired renal function. Forty-one patients with a serum creatinine <200moll(-1) entered the study. Cr-51-EDTA clearance was measured with the standard bolus injection technique and glomerular filtration rate (GFR) was calculated by the single-sample method described by Jacobsson. Mannitol, 025gkg(-1) body weight (150mgml(-1)), was infused for 4-14min and blood samples taken at 1-, 2-, 3- and 4-h (n=24) or 2-, 3-, 35- and 4-h after infusion (n=17). Mannitol in serum was measured by an enzymatic method. Plasma clearance for mannitol and its apparent volume of distribution (Vd) were calculated according to BrOchner-Mortensen. Mean plasma clearance (+/- SD) for Cr-51-EDTA was 597 +/- 188mlmin(-1). The mean plasma clearance for mannitol ranged between 570 +/- 201 and 611 +/- 167mlmin(-1) and Vd was 213 +/- 62% per kg b.w. The between-method bias ranged between -023 and 273mlmin(-1), the percentage error between 267 and 395% and the limits of agreement between -143/172 and -253/199mlmin(-1). The best agreement was seen when three- or four-sample measurements of plasma mannitol were obtained and when sampling started 60min after injection. Furthermore, accuracy of plasma clearance determinations was 88-96% (P30) and 41-63% (P10) and was highest when three- or four-sample measurements of plasma mannitol were obtained, including the first hour after the bolus dose. We conclude that there is a good agreement between plasma clearances of mannitol and Cr-51-EDTA for the assessment of GFR.
|
|
| 7. |
- Lindgren, Sophie, 1971, et al.
(författare)
-
Regional lung derecruitment after endotracheal suction during volume- or pressure-controlled ventilation: a study using electric impedance tomography
- 2007
-
Ingår i: Intensive care medicine. - 0342-4642. ; 33:1, s. 172-80
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To assess lung volume and compliance changes during open- and closed-system suctioning using electric impedance tomography (EIT) during volume- or pressure-controlled ventilation. DESIGN AND SETTING: Experimental study in a university research laboratory. SUBJECTS: Nine bronchoalveolar saline-lavaged pigs. INTERVENTIONS: Open and closed suctioning using a 14-F catheter in volume- or pressure-controlled ventilation at tidal volume 10 ml/kg, respiratory rate 20 breaths/min, and positive end-expiratory pressure 10 cmH2O. MEASUREMENTS AND RESULTS: Lung volume was monitored by EIT and a modified N2 washout/-in technique. Airway pressure was measured via a pressure line in the endotracheal tube. In four ventral-to-dorsal regions of interest regional ventilation and compliance were calculated at baseline and 30 s and 1, 2, and 10 min after suctioning. Blood gases were followed. At disconnection functional residual capacity (FRC) decreased by 58+/-24% of baseline and by a further 22+/-10% during open suctioning. Arterial oxygen tension decreased to 59+/-14% of baseline value 1 min after open suctioning. Regional compliance deteriorated most in the dorsal parts of the lung. Restitution of lung volume and compliance was significantly slower during pressure-controlled than volume-controlled ventilation. CONCLUSIONS: EIT can be used to monitor rapid lung volume changes. The two dorsal regions of the lavaged lungs are most affected by disconnection and suctioning with marked decreases in compliance. Volume-controlled ventilation can be used to rapidly restitute lung aeration and oxygenation after lung collapse induced by open suctioning.
|
|
| 8. |
- Löwhagen Hendén, Pia, et al.
(författare)
-
Can Baroreflex Sensitivity and Heart Rate Variability Predict Late Neurological Outcome in Patients With Traumatic Brain Injury?
- 2014
-
Ingår i: Journal of neurosurgical anesthesiology. - 1537-1921. ; 26:1, s. 50-59
-
Tidskriftsartikel (refereegranskat)abstract
- Previous studies have suggested that depressed heart rate variability (HRV) and baroreflex sensitivity (BRS) are associated with early mortality and morbidity in patients with acute brain injuries of various etiologies. The aim of the present study was to assess changes in HRV and BRS in isolated traumatic brain injury (TBI), with the hypothesis that measurement of autonomic nervous system dysfunction can provide prognostic information on late neurological outcome.
|
|
| 9. |
- Olegård, Cecilia, 1967, et al.
(författare)
-
Validation and clinical feasibility of nitrogen washin/washout functional residual capacity measurements in children.
- 2010
-
Ingår i: Acta anaesthesiologica Scandinavica. - : Wiley. - 1399-6576 .- 0001-5172. ; 54:3, s. 370-6
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The functional residual capacity (FRC) is an important parameter in pediatric respiratory monitoring but it is difficult to assess in the clinical setting. We have introduced a modified N(2) washout method utilizing a change of F(I)O(2) of 0.1 for FRC measurement in adult respiratory monitoring. This study validated the algorithm in a pediatric lung model and investigated the stability and feasibility in a pediatric peri-operative and intensive care setting. METHODS: The lung model was ventilated in combinations of ventilatory modes, CO(2) production, model FRC and respiratory rates. Sixteen children from 10 days to 5 years were studied peri-operatively with controlled ventilation using a Mapleson D system and in the intensive care unit using a Servo-i ventilator in a supported spontaneous mode. FRC was measured during stable metabolic, respiratory and circulatory periods at positive end expiratory pressure of 3-4 and 7-8 cmH(2)O. RESULTS: In the model and in the clinical setting, we found an excellent agreement between washout and washin measurements of FRC as well as acceptable coefficients of repeatability. CONCLUSION: FRC was satisfactorily measured by a modified N(2) algorithm and may be included as a monitoring variable in pediatric respiratory care. Pediatric FRC monitoring demands strictly stable conditions as measurements are performed close to the limits of the monitor's specifications.
|
|
| 10. |
- Pearse, Rupert M, et al.
(författare)
-
Mortality after surgery in Europe: a 7 day cohort study.
- 2012
-
Ingår i: Lancet. - 1474-547X. ; 380:9847, s. 1059-65
-
Tidskriftsartikel (refereegranskat)abstract
- Clinical outcomes after major surgery are poorly described at the national level. Evidence of heterogeneity between hospitals and health-care systems suggests potential to improve care for patients but this potential remains unconfirmed. The European Surgical Outcomes Study was an international study designed to assess outcomes after non-cardiac surgery in Europe.
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
- Söndergaard, Sören, 1951, et al.
(författare)
-
Central venous pressure: we need to bring clinical use into physiological context.
- 2015
-
Ingår i: Acta anaesthesiologica Scandinavica. - : Wiley. - 1399-6576 .- 0001-5172. ; 59:5, s. 552-60
-
Forskningsöversikt (refereegranskat)abstract
- The place of central venous pressure (CVP) measurement in acute care has been questioned during the past decade. We reviewed its physiological importance, utility and clinical use among anaesthetists and intensivists.
|
|
| 14. |
- Söndergaard, Sören, 1951
(författare)
-
Impeding the supply of expertise in Australian health care: actions of the Australian and New Zealand College of Anaesthetists.
- 2008
-
Ingår i: The Medical journal of Australia. - 0025-729X. ; 189:8, s. 460-2
-
Tidskriftsartikel (refereegranskat)abstract
- Australia is an attractive workplace for overseas-trained specialist (OTS) anaesthetists. The path to recognition of the qualifications and experience of OTS anaesthetists is, in my opinion, bogged down in an overzealous assessment procedure. The Australian and New Zealand College of Anaesthetists (ANZCA) is a self-proclaimed professional body that is not subject to regulation by the federal government. Medical authorities such as the Australian Medical Council and state medical boards have no influence on ANZCA's assessment criteria and procedures. In my opinion, the current state of affairs with regard to assessment of OTS anaesthetists can not be justified.
|
|
| 15. |
- Söndergaard, Sören, 1951
(författare)
-
Pavane for a pulse pressure variation defunct.
- 2013
-
Ingår i: Critical care (London, England). - : Springer Science and Business Media LLC. - 1466-609X .- 1364-8535. ; 17:6
-
Tidskriftsartikel (refereegranskat)abstract
- Hemodynamic management of critically ill patients in the ICU or high-risk patients in the operating room has paradoxically shown progress in terms of outcome after the systematic application of volume responsiveness/flow optimization based on pulse pressure variation and/or stroke volume variation during controlled, positive-pressure ventilation in patients without spontaneous respiratory efforts. This assessment of circulatory optimization should ideally be based on an exhaustive, predictive and coherent physiological understanding of the cardiovascular system model. This paper sketches the extremely complex physiological background of the concept of volume responsiveness, concluding that it is not a reliable means of guiding hemodynamic optimization because it is based on a nonexhaustive, nonpredictive and incoherent physiological model.
|
|
| 16. |
- Söndergaard, Sören, 1951
(författare)
-
The dynostatic algorithm in adult and paediatric respiratory monitoring
- 2002
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Positive pressure ventilation carries a risk of aggravating systemic and lung disease. Monitoring of ventilatory pressure and volume is important to minimize this risk. Conventionally, the pressure of the respiratory system is measured outside the patient. Tra-cheal pressure measurement is one step closer the alveoli and alveolar pressure can be cal-culated by an appropriate algorithm. Volume and pressure may possibly be reduced by using low-density gas mixtures of Helium and Oxygen.Methods: A small fibre optic pressure transducer was evaluated for tracheal pressure mea-surement in paediatric patients and a polyethylene catheter for pressure measurement in adult patients. The dynostatic algorithm (DSA) is based on the equation of motion and the assumption of equal inspiratory and expiratory resistance and compliance at isovolume. The DSA utilises flow and tracheal pressure signals to calculate an alveolar P/V- and an alveolar P/t-curve continuously during ongoing ventilation. The DSA was evaluated clini-cally and in lung models by comparison of calculated and measured alveolar pressure. A Pitot type venturimeter was calibrated for use with low-density gas mixtures; the calibra-tion may be incorporated in the DSA for a preliminary clinical study using He/O2. Results: The fibre optic pressure transducer and polyethylene catheter functioned satisfac-torily in clinical pressure measurement in intubated positive pressure ventilated children and adults, respectively. The tracheal pressure recording provided an improved possibility of detecting peak inspiratory pressure and intrinsic PEEP compared to proximal measure-ment. The DSA reliably calculated alveolar pressure in lung models and provided a number of interesting clinical observations concerning inflection points and overdistension.Conclusions: The Dynostatic Algorithm offers the clinician the option of improved respiratory monitoring in adult and paediatric intensive care patients.
|
|
