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9 results

  • Periods of low renal perfusion pressure are associated with acute kidney injury following paediatric cardiac surgery

  • Jamie S. Penk, Katja M. Gist, Matthew Barhight, Karl Migally, Santiago Borasino, Wendy F. Torres, Siyuan Dong, Bradley S. Marino, Catherine D. Krawczeski
  • Journal:
    Cardiology in the Young , First View
    Published online by Cambridge University Press:
    16 May 2024, pp. 1-6
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  • Introduction:

    Acute kidney injury is associated with worse outcomes after cardiac surgery. The haemodynamic goals to ameliorate kidney injury are not clear. Low post-operative renal perfusion pressure has been associated with acute kidney injury in adults. Inadequate oxygen delivery may also cause kidney injury. This study evaluates pressure and oximetric haemodynamics after paediatric cardiac surgery and their association with acute kidney injury.

    Materials and Methods:

    Retrospective case–control study at a children’s hospital. Patients were < 6 months of age who underwent a Society of Thoracic Surgery-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery categories ≥ 3. Low renal perfusion pressure was time and depth below several tested thresholds. The primary outcome was serum creatine-defined acute kidney injury in the first 7 days.

    Results:

    Sixty-six patients (median age 8 days) were included. Acute kidney injury occurred in 36%. The time and depth of renal perfusion pressure < 42 mmHg in the first 24 hours was greater in acute kidney injury patients (94 versus 35 mmHg*minutes of low renal perfusion pressure/hour, p = 0.008). In the multivariable model, renal perfusion pressure < 42 mmHg was associated with acute kidney injury (aOR: 2.07, 95%CI: 1.25–3.82, p = 0.009). Mean arterial pressure, central venous pressure, and measures of inadequate oxygen delivery were not associated with acute kidney injury.

    Conclusion:

    Periods of low renal perfusion pressure (<42 mmHg) in the first 24 post-operative hours are associated with acute kidney injury. Renal perfusion pressure is a potential modifiable target that may mitigate the impact of acute kidney injury after paediatric cardiac surgery.

  • Chapter 17 - Haemodynamic Monitoring

  • Edited by Daniel Rodger, Kevin Henshaw, Paul Rawling, Scott Miller
  • Book:
    Fundamentals of Operating Department Practice
    Published online:
    18 August 2022
    Print publication:
    08 September 2022, pp 180-190

  • Summary

    Critical ill patients are often haemodynamically unstable and accurate continuous monitoring is vital. Haemodynamic monitoring describes the measurement of the cardiovascular stability of the patient. Invasive blood pressure monitoring and central venous pressure monitoring provide a ‘real time’ measurement of the patients haemodynamic status and better allows clinicians to pre-emptively treat a patient before a more serious problem arises. Although invasive blood pressure monitoring has several advantages compared to non-invasive blood pressure monitoring, it is not without risk. Central venous pressure monitoring is similarly beneficial in that it supports the clinical decision making regarding a patient’s fluid status but also comes with additional risks. This chapter explores invasive blood pressure and central venous pressure monitoring in detail.

  • P056: Non-invasive measurement of the central venous pressure using near-infrared spectroscopy versus point-of-care ultrasound

  • N. Goumeniouk, J. Newbigging, M. McDonnell, M.L.A. Sivilotti
  • Journal:
    Canadian Journal of Emergency Medicine / Volume 20 / Issue S1 / May 2018
    Published online by Cambridge University Press:
    11 May 2018, pp. S76-S77
    Print publication:
    May 2018
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  • Introduction: A fundamental hemodynamic parameter, the central venous pressure (CVP) is rarely available in the emergency patient due the delay and risks inherent to central vein cannulation. Recently, two non-invasive strategies have emerged: a) point-of-care ultrasound to supplement traditional inspection the internal jugular waveform ; or b) near-infrared spectroscopy (NIRS) of the external jugular vein. Methods: Five medical students underwent standardized training on both NIRS device (Venus 2000 CVP; Mespere Life Sciences, Waterloo ON) and ultrasound-assisted CVP assessment. During prescheduled, randomly permuted and balanced shifts, a pair of students obtained blinded independent measurements using each device within 10 minutes of each other. High priority subjects likely to have abnormal CVP (e.g. vomiting, dehydrated, heart failure, sepsis) were approached preferentially, followed by a convenience sample of other eligible patients in the emergency department. Secondary outcomes were stopwatch-recorded time from device ready to stable measurement, as well as operator ease, operator confidence and patient discomfort. The blinded treating physician rated each subjects volume status on an ordered scale: depleted, neutral and overloaded. Results: We enrolled 104 patients (median [IQR] age 68 [53, 78] years; 50% male; BMI 27.6 [17.0, 47.7] kg/m2; admission rate 27%) in June-August 2017. Treating physicians classified 17 as volume depleted and 12 overloaded. CVP measurements differed widely between techniques: ultrasound 8 [7, 9] cmH2O (3 cases unobtainable) vs NIRS 12 [8, 17] cmH2O (13 unobtainable). Agreement and correlation between the two devices was extremely low (R2=0.04). While neither technique demonstrated a strong association with the treating physicians estimate of volume status, only the ultrasound values increased monotonically with physician estimate. With regards to secondary outcomes, ultrasound measurements took less time (paired difference 50 seconds [95% CI 7, 93]), and operators were more confident (0.63 [0.02, 1.23] out of 10) and at ease (0.78, [0.13, 1.43]) with ultrasound; patients rated discomfort equally (-0.06 [-0.30, 0.18]). Conclusion: Non-invasive measurement of CVP remains a challenge in the emergency department. The external jugular pressure by NIRS has very high variability and poor agreement with ultrasound-enhanced inspection of the internal jugular, suggesting that this technique is not yet practical for use by non-experts.

  • 12 - Severe pelvic trauma

  • from Section 2 - Trauma
  • Edited by Kaushal Shah, Jarone Lee, Kamal Medlej, American University of Beirut, Scott D. Weingart
  • Book:
    Practical Emergency Resuscitation and Critical Care
    Published online:
    05 November 2013
    Print publication:
    24 October 2013, pp 90-95

  • Summary

    This chapter discusses the basic methods and principles of monitoring for proper management of the critically ill patient in the emergency setting. Pulse oximetry provides continuous measurement of a patient's oxygenation status in the case of respiratory monitoring. Capnography measures the partial pressure or concentration of expired carbon dioxide (CO2), the end-tidal carbon dioxide (EtCO2). Ultrasonography of the inferior vena cava (IVC) can be useful in determining fluid responsiveness during non-invasive hemodynamic monitoring. Invasive hemodynamic monitoring provides data via catheters inserted in central veins or arteries. Central venous pressure is obtained by placing a central venous catheter (CVC) in the internal jugular or subclavian vein. The CVP should be interpreted with caution in critically ill patients that have known heart disease or structural cardiac anomalies. Pulse pressure variation (PPV) and systolic pressure variation (SPV) can be used to determine fluid responsiveness in a mechanically ventilated patient.

  • Chapter 31 - Sepsis

  • from Section 4 - The pregnant patient with coexisting disease
  • Edited by Marc van de Velde, Helen Scholefield, Lauren A. Plante
  • Book:
    Maternal Critical Care
    Published online:
    05 July 2013
    Print publication:
    04 July 2013, pp 346-355

  • Summary

    Intensivists, physicians specially trained in critical care medicine, and other members of the ICU care team may have in-depth knowledge of monitors not available to the practitioner, who does not use them on a daily basis. The most commonly encountered non-invasive monitors are electrocardiography (ECG), pulse oximetry, blood pressure measurement by manometry, urine output, pulse oximetry and end-tidal carbon dioxide monitoring. Central venous pressure (CVP) is measured by placing a catheter into or near the right atrium or vena cava. Central venous pressure can be measured via a small microcatheter inserted into the frontal white matter. The physiological basis for intracranial pressure (ICP) monitoring is based on two separate but related mechanisms that contribute to cerebral ischemia. Fetal monitoring, in practice, is generally limited to the generation and interpretation of fetal heart rate patterns obtained through Doppler ultrasound.

  • Defining normal jugular venous pressure with ultrasonography

  • Steven J. Socransky, Ray Wiss, Ron Robins, Alexandre Anawati, Marc-Andre Roy, I. Ching Yeung
  • Journal:
    Canadian Journal of Emergency Medicine / Volume 12 / Issue 4 / July 2010
    Published online by Cambridge University Press:
    21 May 2015, pp. 320-324
    Print publication:
    July 2010
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  • Objective:

    Determination of jugular venous pressure (JVP) by physical examination (E-JVP) is unreliable. Measurement of JVP with ultrasonography (U-JVP) is easy to perform, but the normal range is unknown. The objective of this study was to determine the normal range for U-JVP.

    Methods:

    We conducted a prospective anatomic study on a convenience sample of emergency department (ED) patients over 35 years of age. We excluded patients who had findings on history or physical examination suggesting an alteration of JVP. With the head of the bed at 45°, we determined the point at which the diameter of the internal jugular vein (IJV) began to decrease on ultrasonography (“the taper”). Research assistants used 2 techniques to measure U-JVP in all participants: by measuring the vertical height (in centimetres) of the taper above the sternal angle, and adding 5 cm; and by recording the quadrant in the IJV's path from the clavicle to the angle of the jaw in which the taper was located. To determine interrater reliability, separate examiners measured the U-JVP of 15 participants.

    Results:

    We successfully determined the U-JVP of all 77 participants (38 male and 39 female). The mean U-JVP was 6.35 (95% confidence interval 6.11–6.59) cm. In 76 participants (98.7%), the taper was located in the first quadrant. Determination of interrater reliability found κ values of 1.00 and 0.87 for techniques 1 and 2, respectively.

    Conclusion:

    The normal U-JVP is 6.35 cm, a value that is slightly lower than the published normal E-JVP. Interrater reliability for U-JVP is excellent. The top of the IJV column is located less than 25% of the distance from the clavicle to the angle of the jaw in the majority of healthy adults. Our findings suggest that U-JVP provides the potential to reincorporate reliable JVP measurement into clinical assessment in the ED. However, further research in this area is warranted.

  • Chapter 16 - Multiple organ failure

  • from Section II: - Systemic disorders and management
  • Edited by Fang Gao Smith, University of Warwick
  • Edited in association with Joyce Yeung
  • Book:
    Core Topics in Critical Care Medicine
    Published online:
    06 July 2010
    Print publication:
    22 April 2010, pp 108-115

  • Summary

    This chapter focuses on invasive blood pressure monitoring, and components of the invasive blood pressure monitoring system. It explains the complications of invasive blood pressure monitoring, central venous pressure monitoring and cardiac output monitoring. Central venous pressure monitoring measures pressure in the great veins of the thorax usually the superior vena cava and the right atrium. It involves introducing a catheter into a vein so that the tip of the catheter lies at the junction of the superior vena cava and the right atrium. Haemodynamic monitoring is most informative when it is used to supplement clinical judgement. Clinical parameters may be used to determine cardiac output. Poor cerebral perfusion leads to agitation and confusion. A reduction in renal perfusion leads to decreased urine output and subsequently to anuria. Skin perfusion is a clinically useful sign and can be determined using the capillary refill time.

  • Respiratory variations in pulse oximeter waveform amplitude are influenced by venous return in mechanically ventilated patients under general anaesthesia

  • M. Cannesson, O. Desebbe, M. Hachemi, D. Jacques, O. Bastien, J.-J Lehot
  • Journal:
    European Journal of Anaesthesiology / Volume 24 / Issue 3 / March 2007
    Published online by Cambridge University Press:
    01 March 2007, pp. 245-251
    Print publication:
    March 2007
  • Background and objectives

    Respiratory variations in pulse oximetry plethysmographic waveform amplitude (ΔPOP) are related to respiratory variations in arterial pulse pressure (ΔPP) in the critical care setting. The aims of this study were to test the hypothesis that in mechanically ventilated patients undergoing general anaesthesia, ΔPOP calculation is feasible and can detect changes in preload.

    Methods

    Twenty-five mechanically ventilated patients were studied immediately after induction of general anaesthesia. Haemodynamic data (mean arterial pressure [MAP], central venous pressure [CVP], ΔPP and ΔPOP) were recorded at baseline, before and after tilting the patient from anti-Trendelenburg to Trendelenburg position in order to induce preload changes.

    Results

    Change from anti-Trendelenburg to Trendelenburg position induced changes in MAP (58 ± 9 to 67 ± 10 mmHg, P < 0.05), CVP (4 ± 4 to 13 ± 5 mmHg, P < 0.05), ΔPP (14 ± 8 to 7 ± 5%, P < 0.05) and ΔPOP (17 ± 12 to 9 ± 5%, P < 0.05). There was a significant relationship between ΔPOP in anti-Trendelenburg position and percent change in MAP after volume expansion (r = 0.82; P < 0.05).

    Conclusions

    ΔPOP can be determined in the operating room and is influenced by changes in preload. This new index has potential clinical applications for the prediction of fluid responsiveness.

  • Effects of positive end-expiratory pressure on systemic haemodynamics, with special interest to central venous and common iliac venous pressure in liver transplanted patients

  • F. H. Saner, G. Pavlakovic, Y. Gu, J. Gensicke, A. Paul, A. Radtke, M. Bockhorn, N. R. Fruhauf, S. Nadalin, M. Malagó, C. E. Broelsch
  • Journal:
    European Journal of Anaesthesiology / Volume 23 / Issue 9 / September 2006
    Published online by Cambridge University Press:
    24 May 2006, pp. 766-771
    Print publication:
    September 2006

  • Summary

    Background and objectives: Positive end-expiratory pressure may alter cardiac function and systemic haemodynamics. As transplanted livers may be sensitive to liver congestion, the aim of our study was to evaluate the effect of positive end-expiratory pressure on the cardiovascular system and in particular on central venous and iliac venous pressure in liver transplanted patients. Patients and methods: Seventy-two liver transplant patients were enrolled in this prospective, interventional study. On admission to our Intensive Care Unit all patients were ventilated in a biphasic positive airway pressure mode. Haemodynamic effects of three randomly set levels of end-expiratory pressures (0, 5 and 10 mbar) were studied in the immediate postoperative period in all patients. Mean arterial pressure, central venous pressure, pulmonary capillary wedge pressure, central iliac venous pressure and cardiac index were recorded and analysed at each of the three end-expiratory pressure levels. Results: The values of central- and wedge-pressure significantly increased with increased end-expiratory pressure. Central venous pressure increased by 24% and wedge pressure showed a 6% increase at 10 mbar in comparison to 0 mbar. The values for cardiac index and mean arterial pressure showed no statistically significant difference at 10 mbar as compared to 0 and 5 mbar. The mean pulmonary arterial and common iliac venous pressure were unaffected by different positive end-expiratory pressure levels. Conclusions: Short-term pressure controlled ventilation with end-expiratory pressure up to 10 mbar does not significantly impair systemic haemodynamics in liver-transplanted patients. Further studies are needed to determine whether these findings could be confirmed with higher pressure levels and/or over a longer period of ventilation time.