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Bihari S, Wiersema UF. Changes in Respiratory Mechanics With Trunk Inclination Differs Between Patients With ARDS With and Without Obesity. Chest 2024; 165:583-589. [PMID: 37832782 DOI: 10.1016/j.chest.2023.09.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND Studies investigating the effect of trunk inclination on respiratory mechanics in mechanically ventilated patients with ARDS have reported postural differences in partition respiratory mechanics. Compared with more upright positions, the supine-flat position provided lower lung and chest wall elastance, allowing reduced driving pressures and end-inspiratory transpulmonary pressure. However, the effect of trunk inclination on respiratory mechanics in patients with obesity and ARDS is uncertain. RESEARCH QUESTION Does the effect of change in posture on partition respiratory mechanics differ between patients with ARDS with and without obesity? STUDY DESIGN AND METHODS In this single-center study, patients with ARDS with and without obesity were randomized into two 15-minute steps in which trunk inclination was changed from semi-recumbent (40° head up) to supine-flat (0°), or vice versa. At the end of each step partition respiratory mechanics, airway opening pressure and arterial blood gases were measured. Paired t test was used to examine respiratory mechanics and blood gas variables in each group. RESULTS Forty consecutive patients were enrolled. Twenty were obese (BMI, 38.4 [34.5-42.3]), and 20 were non-obese (BMI, 26.6 [25.2-28.5]). In the patients with obesity, lung and chest wall elastance, driving pressure, inspiratory transpulmonary pressure, Paco2, and ventilatory ratio were lower supine than semi-recumbent (P < .001). Airways resistance was greater supine (P = .006). In the patients without obesity, only chest wall elastance was lower in supine vs semi-recumbent (P < .001). INTERPRETATION In mechanically ventilated patients with ARDS and obesity, supine posture provided lower lung and chest wall elastance, and better CO2 clearance, than the semi-recumbent posture. CLINICAL TRIAL REGISTRATION This study was registered with Australian New Zealand Clinical Trials Registry (ACTRN12623000794606).
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Affiliation(s)
- Shailesh Bihari
- Department of ICCU, Flinders Medical Centre, Bedford Park, SA, Australia; College of Medicine and Public Health, Flinders University, Bedford Park, SA, Australia.
| | - Ubbo F Wiersema
- Department of ICCU, Flinders Medical Centre, Bedford Park, SA, Australia
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Maher D, Larcombe R, Potts SD, Wiersema UF. Antimicrobial stewardship in intensive care: identifying areas for improvement. J Pharm Pract Res 2020. [DOI: 10.1002/jppr.1667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Dorsa Maher
- Pharmacist Flinders Medical Centre SA Pharmacy Bedford Park Australia
- PhD Candidate Clinical and Health Sciences University of South Australia Adelaide Australia
| | - Rebecca Larcombe
- Deputy Director Pharmacy Flinders Medical Centre SA Pharmacy Bedford Park Australia
| | - Simon D. Potts
- Senior Pharmacist, Intensive and Critical Care Unit Flinders Medical Centre SA Pharmacy Bedford Park Australia
| | - Ubbo F. Wiersema
- Consultant, Intensive and Critical Care Unit Flinders Medical Centre Bedford Park Australia
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Khan KS, Wiersema UF. Transcranial Doppler waveform changes due to increased cerebrovascular resistance and raised intracranial pressure in a patient with cirrhosis: A difference in shapes, not in numbers. J Clin Ultrasound 2020; 48:59-63. [PMID: 31774180 DOI: 10.1002/jcu.22799] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/18/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
We report and discuss a case that illustrate the clinical utility of transcranial Doppler (TCD) ultrasound in a patient with cirrhosis. A 43-year-old female presented with acute decompensation of cirrhosis with hepatic encephalopathy, requiring mechanical ventilation. TCD showed low diastolic flow velocities and high pulsatility index (PI) consistent with increased cerebrovascular resistance (CVR). The flow velocities and PI normalized over a period of few days and correlated well with neurological improvement after treatment. Subsequently, the patient developed a large intracerebral hemorrhage with mass effect. The TCD measurements in intracranial hypertension were similar to those with cirrhosis and hepatic encephalopathy. However, the windkessel notch in the systolic phase of TCD waveform, related to the distensibility of arterial wall, was absent during raised intracranial pressure (ICP). The absence of a windkessel notch may help to differentiate a high downstream resistance due to raised ICP from increased CVR.
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Affiliation(s)
- Khurram S Khan
- Intensive and Critical Care Unit, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - Ubbo F Wiersema
- Intensive and Critical Care Unit, Flinders Medical Centre, Bedford Park, South Australia, Australia
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Bihari S, Wiersema UF, Perry R, Schembri D, Bouchier T, Dixon D, Wong T, Bersten AD. Efficacy and safety of 20% albumin fluid loading in healthy subjects: a comparison of four resuscitation fluids. J Appl Physiol (1985) 2019; 126:1646-1660. [DOI: 10.1152/japplphysiol.01058.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Recently, buffered salt solutions and 20% albumin (small volume resuscitation) have been advocated as an alternative fluid for intravenous resuscitation. The relative comparative efficacy and potential adverse effects of these solutions have not been evaluated. In a randomized, double blind, cross-over study of six healthy male subjects we compared the pulmonary and hemodynamic effects of intravenous administration of 30 ml/kg of 0.9% saline, Hartmann's solution and 4% albumin, and 6 ml/kg of 20% albumin (albumin dose equivalent). Lung tests (spirometry, ultrasound, impulse oscillometry, diffusion capacity, and plethysmography), two- to three-dimensional Doppler echocardiography, carotid applanation tonometry, blood gases, serum/urine markers of endothelial, and kidney injury were measured before and after each fluid bolus. Data were analyzed with repeated measures ANOVA with effect of fluid type examined as an interaction. Crystalloids caused lung edema [increase in ultrasound B line ( P = 0.006) and airway resistance ( P = 0.009)], but evidence of lung injury [increased angiopoietin-2 ( P = 0.019)] and glycocalyx injury [increased syndecan ( P = 0.026)] was only observed with 0.9% saline. The colloids caused greater left atrial stretch, decrease in lung volumes, and increase in diffusion capacity than the crystalloids, but without pulmonary edema. Stroke work increased proportionally to increase in preload with all four fluids ( R2 = 0.71). There was a greater increase in cardiac output and stroke volume after colloid administration, associated with a reduction in afterload. Hartmann’s solution did not significantly alter ventricular performance. Markers of kidney injury were not affected by any of the fluids administrated. Bolus administration of 20% albumin is both effective and safe in healthy subjects. NEW & NOTEWORTHY Bolus administration of 20% albumin is both effective and safe in healthy subjects when compared with other commonly available crystalloids and colloidal solution.
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Affiliation(s)
- Shailesh Bihari
- Intensive and Critical Care Unit, Flinders Medical Centre, Bedford Park, South Australia, Australia
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Ubbo F Wiersema
- Intensive and Critical Care Unit, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - Rebecca Perry
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
- Department of Cardiovascular Medicine, Flinders Medical Centre, Bedford Park, South Australia, Australia
- Department of Heart Health, South Australian Health and Medical Research Institute, Adelaide, Australia
| | - David Schembri
- Department of Respiratory Medicine, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - Tara Bouchier
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Dani Dixon
- Intensive and Critical Care Unit, Flinders Medical Centre, Bedford Park, South Australia, Australia
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Teresa Wong
- Intensive and Critical Care Unit, Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - Andrew D Bersten
- Intensive and Critical Care Unit, Flinders Medical Centre, Bedford Park, South Australia, Australia
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
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Bihari S, Wiersema UF, Schembri D, De Pasquale CG, Dixon DL, Prakash S, Lawrence MD, Bowden JJ, Bersten AD. Bolus intravenous 0.9% saline, but not 4% albumin or 5% glucose, causes interstitial pulmonary edema in healthy subjects. J Appl Physiol (1985) 2015; 119:783-92. [PMID: 26228998 DOI: 10.1152/japplphysiol.00356.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 07/23/2015] [Indexed: 01/08/2023] Open
Abstract
Rapid intravenous (iv) infusion of 0.9% saline alters respiratory mechanics in healthy subjects. However, the relative cardiovascular and respiratory effects of bolus iv crystalloid vs. colloid are unknown. Six healthy male volunteers were given 30 ml/kg iv 0.9% saline, 4% albumin, and 5% glucose at a rate of 100 ml/min on 3 separate days in a double-blinded, randomized crossover study. Impulse oscillometry, spirometry, lung volumes, diffusing capacity (DLCO), and blood samples were measured before and after fluid administration. Lung ultrasound B-line score (indicating interstitial pulmonary edema) and Doppler echocardiography indices of cardiac preload were measured before, midway, immediately after, and 1 h after fluid administration. Infusion of 0.9% saline increased small airway resistance at 5 Hz (P = 0.04) and lung ultrasound B-line score (P = 0.01) without changes in Doppler echocardiography measures of preload. In contrast, 4% albumin increased DLCO, decreased lung volumes, and increased the Doppler echocardiography mitral E velocity (P = 0.001) and E-to-lateral/septal e' ratio, estimated blood volume, and N-terminal pro B-type natriuretic peptide (P = 0.01) but not lung ultrasound B-line score, consistent with increased pulmonary blood volume without interstitial pulmonary edema. There were no significant changes with 5% glucose. Plasma angiopoietin-2 concentration increased only after 0.9% saline (P = 0.001), suggesting an inflammatory mechanism associated with edema formation. In healthy subjects, 0.9% saline and 4% albumin have differential pulmonary effects not attributable to passive fluid filtration. This may reflect either different effects of these fluids on active signaling in the pulmonary circulation or a protective effect of albumin.
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Affiliation(s)
- Shailesh Bihari
- Intensive and Critical Care Unit, Flinders Medical Centre, Adelaide, Australia; Department of Critical Care Medicine, Flinders University, Adelaide, Australia;
| | - Ubbo F Wiersema
- Intensive and Critical Care Unit, Flinders Medical Centre, Adelaide, Australia
| | - David Schembri
- Department of Respiratory Medicine, Flinders Medical Centre, Adelaide, Australia
| | - Carmine G De Pasquale
- Cardiology, Flinders Medical Centre, Adelaide, Australia; and Department of Medicine, Flinders University, Adelaide, Australia
| | - Dani-Louise Dixon
- Intensive and Critical Care Unit, Flinders Medical Centre, Adelaide, Australia; Department of Critical Care Medicine, Flinders University, Adelaide, Australia
| | - Shivesh Prakash
- Intensive and Critical Care Unit, Flinders Medical Centre, Adelaide, Australia
| | - Mark D Lawrence
- Department of Critical Care Medicine, Flinders University, Adelaide, Australia
| | - Jeffrey J Bowden
- Department of Respiratory Medicine, Flinders Medical Centre, Adelaide, Australia
| | - Andrew D Bersten
- Intensive and Critical Care Unit, Flinders Medical Centre, Adelaide, Australia; Department of Critical Care Medicine, Flinders University, Adelaide, Australia
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Laver RD, Wiersema UF, Bersten AD. Echocardiographic estimation of mean pulmonary artery pressure in critically ill patients. Crit Ultrasound J 2014; 6:9. [PMID: 25024842 PMCID: PMC4086993 DOI: 10.1186/2036-7902-6-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 06/24/2014] [Indexed: 11/25/2022] Open
Abstract
Background Indirect assessment of mean pulmonary arterial pressure (MPAP) may assist management of critically ill patients with pulmonary hypertension and right heart dysfunction. MPAP can be estimated as the sum of echocardiographically derived mean right ventricular to right atrial systolic pressure gradient and right atrial pressure; however, this has not been validated in critically ill patients. Methods This prospective validation study was conducted in patients undergoing pulmonary artery catheterisation during intensive care admission. Pulmonary artery catheter (PAC) measurements of MPAP were contemporaneously compared to MPAP estimated utilising transthoracic echocardiography (TTE)-derived mean right ventricular to right atrial systolic pressure gradient added to invasively measured right atrial pressure. Results Of 53 patients assessed, 23 had estimable MPAP using TTE. The mean difference between TTE- and PAC-derived MPAP was 1.9 mmHg (SD 5.0), with upper and lower limits of agreement of 11.6 and −7.9 mmHg, respectively. The median absolute percentage difference between TTE- and PAC-derived MPAP was 7.5%. Inter-rater reliability assessment was performed for 15 patients, giving an intra-class correlation coefficient of 0.96 (95% confidence intervals, 0.89 to 0.99). Conclusions This echocardiographic method of estimating MPAP in critically ill patients was not equivalent to invasively measured MPAP, based on our predefined clinically acceptable range (±5 mmHg). The accuracy of this method in critically ill patients was similar to the results obtained in ambulatory patients and compared favourably with regard to the accuracy with echocardiographic estimation of systolic pulmonary arterial pressure. The utility of this technique is limited by frequent inability to obtain an adequate tricuspid regurgitant time-velocity integral in critically ill patients.
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Affiliation(s)
- Russell D Laver
- Intensive and Critical Care Unit, Flinders Medical Centre, Flinders Drive, Bedford Park, SA 5042, Australia
| | - Ubbo F Wiersema
- Intensive and Critical Care Unit, Flinders Medical Centre, Flinders Drive, Bedford Park, SA 5042, Australia
| | - Andrew D Bersten
- Intensive and Critical Care Unit, Flinders Medical Centre, Flinders Drive, Bedford Park, SA 5042, Australia ; School of Medicine, Flinders University, Sturt Road, Bedford Park, SA 5042, Australia
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