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H Wrigge

Publications and source records attributed to H Wrigge.

16 recordsLinked to original sources
PubMed2005

Influence of intra-aortic balloon pumping on cerebral blood flow pattern in patients after cardiac surgery.

BACKGROUND AND OBJECTIVE: The effects of intra-aortic balloon pumping (IABP) on cerebral perfusion are still a matter of debate. End-diastolic reversal of blood flow in cerebral arteries has been observed in a small number of patients. We prospectively investigated the incidence and the amount of transient cerebral artery blood flow reversal during balloon pumping in patients recovering from cardiac surgery. METHODS: In 23 patients receiving IABP support, blood flow velocities in the right middle cerebral artery were assessed by transcranial Doppler-sonography. Additionally, systemic haemodynamics were monitored. In each patient, measurements were performed at three different pump settings: without support, assist ratio 1 : 1 and assist ratio 1 : 2. RESULTS: In 8 of 23 patients, balloon pumping caused a transient diastolic reversal of blood flow in the middle cerebral artery during balloon deflation. Antegrade mean flow velocity in the middle cerebral artery significantly increased from 57 +/- 27 to 61 +/- 26 (assist ratio 1 : 1) and 61 +/- 29 cm s(-1) (assist ratio 1 : 2) (P < 0.05). Taking transient blood flow reversal into account, net mean flow velocity did not increase with balloon pump support. Systemic haemodynamic parameters remained unchanged. CONCLUSION: Left ventricular support with IABP significantly changed flow patterns in basal cerebral arteries of our patients. In 35% of patients, support resulted in a transient reversal of intracranial blood flow which counterbalanced a slight increase in mean antegrade flow.

Aged↗
PubMed2003

[Proportional assist ventilation combined with automatic tube compensation. A promising concept of augmented spontaneous breathing?].

The combination of proportional assist ventilation (PAV) and automatic tube compensation (ATC) is a promising concept for partial ventilatory support. In contrast to conventional pressure support ventilation (PSV), PAV+ATC provides dynamic pressure support depending on the patient's initial inspiratory effort. PAV+ATC should selectively unload the respiratory muscles from the additional workload imposed by increased respiratory system resistance and elastance as well as by endotracheal tube resistance. Patients have the ability to modify the tidal volume in response to changes in ventilatory demand, thereby improving patient-ventilator interaction and breathing comfort when compared with PSV. However, since routine measurements of respiratory mechanics during augmented spontaneous breathing are currently unavailable but would be necessary for setting the support level as a function of respiratory system mechanics during PAV, this mode cannot yet be generally recommended for routine clinical use.

Air Pressure↗
PubMed2002

Kinetic and reversibility of mechanical ventilation-associated pulmonary and systemic inflammatory response in patients with acute lung injury.

OBJECTIVE: To investigate the kinetic and reversibility of mechanical ventilation-associated pulmonary and systemic inflammatory response in patients with acute lung injury (ALI). DESIGN: Prospective observational cross-over study. SETTING: Intensive care unit of a university hospital. PATIENTS: Twelve mechanically ventilated patients with ALI. INTERVENTIONS: Mechanical ventilation was transiently changed from a lung protective setting with PEEP of 15 cmH(2)O and a V(T) of 5 ml/kg predicted body weight to a more conventional ventilatory setting with PEEP of 5 cmH(2)O and V(T) of 12 ml/kg predicted body weight for a period of 6 h. MEASUREMENTS AND RESULTS: We examined the profile of interleukin (IL)-1beta, IL-1 receptor antagonist, IL-6, IL-10, and tumor necrosis factor in the plasma of all patients, and in the bronchoalveolar lavage (mini-BAL) fluid of six of these patients. Measurements were performed at baseline, 1 h, and 6 h after each change of the ventilatory setting. Switching to conventional mechanical ventilation was associated with a higher PaO(2) ( P < 0.05) and a marked increase ( P < 0.05) of measured plasma cytokines in patients with and without mini-BAL with a maximum after 1 h. Similarly, intraalveolar cytokine concentrations increased with conventional mechanical ventilation. While plasma cytokine levels returned to baseline values, intraalveolar cytokine concentrations further increased when lung protective mechanical ventilation was reestablished. CONCLUSIONS: In patients with ALI, initiation of low PEEP and high V(T) mechanical ventilation is associated with cytokine release into circulation which occurred within 1 h. It is independent from BAL procedures and can be reversed by reinstitution of lung protective mechanical ventilation.

Bronchoalveolar Lavage Fluid↗
PubMed2001

Long-term effects of spontaneous breathing during ventilatory support in patients with acute lung injury.

Improved gas exchange has been observed during spontaneous breathing with airway pressure release ventilation (APRV) as compared with controlled mechanical ventilation. This study was designed to determine whether use of APRV with spontaneous breathing as a primary ventilatory support modality better prevents deterioration of cardiopulmonary function than does initial controlled mechanical ventilation in patients at risk for acute respiratory distress syndrome (ARDS). Thirty patients with multiple trauma were randomly assigned to either breathe spontaneously with APRV (APRV Group) (n = 15) or to receive pressure-controlled, time-cycled mechanical ventilation (PCV) for 72 h followed by weaning with APRV (PCV Group) (n = 15). Patients maintained spontaneous breathing during APRV with continuous infusion of sufentanil and midazolam (Ramsay sedation score [RSS] of 3). Absence of spontaneous breathing (PCV Group) was induced with sufentanil and midazolam (RSS of 5) and neuromuscular blockade. Primary use of APRV was associated with increases (p < 0.05) in respiratory system compliance (CRS), arterial oxygen tension (PaO2), cardiac index (CI), and oxygen delivery (DO2), and with reductions (p < 0.05) in venous admixture (QVA/QT), and oxygen extraction. In contrast, patients who received 72 h of PCV had lower CRS, PaO2, CI, DO2, and Q VA/Q T values (p < 0.05) and required higher doses of sufentanil (p < 0.05), midazolam (p < 0.05), noradrenalin (p < 0.05), and dobutamine (p < 0.05). CRS, PaO2), CI and DO2 were lowest (p < 0.05) and Q VA/Q T was highest (p < 0.05) during PCV. Primary use of APRV was consistently associated with a shorter duration of ventilatory support (APRV Group: 15 +/- 2 d [mean +/- SEM]; PCV Group: 21 +/- 2 d) (p < 0.05) and length of intensive care unit (ICU) stay (APRV Group: 23 +/- 2 d; PCV Group: 30 +/- 2 d) (p < 0.05). These findings indicate that maintaining spontaneous breathing during APRV requires less sedation and improves cardiopulmonary function, presumably by recruiting nonventilated lung units, requiring a shorter duration of ventilatory support and ICU stay.

Adult↗
PubMed2001

The effects of prone positioning on intraabdominal pressure and cardiovascular and renal function in patients with acute lung injury.

UNLABELLED: To detect any harmful effects of prone positioning on intraabdominal pressure (IAP) and cardiovascular and renal function, we studied 16 mechanically ventilated patients with acute lung injury randomly in prone and supine positions, without minimizing the restriction of the abdomen. Effective renal blood flow index and glomerular filtration rate index were determined by the paraaminohippurate and inulin clearance techniques. Prone positioning resulted in an increase in IAP from 12 +/- 4 to 14 +/- 5 mm Hg (P < 0.05), PaO(2)/fraction of inspired oxygen from 220 +/- 91 to 267 +/- 82 mm Hg (P < 0.05), cardiac index from 4.1 +/- 1.1 to 4.4 +/- 0.7 L/min (P < 0.05), mean arterial pressure from 77 +/- 10 to 82 +/- 11 mm Hg (P < 0.01), and oxygen delivery index from 600 +/- 156 to 648 +/- 95 mL. min(-)(1). m(-)(2) (P < 0.05). Renal fraction of cardiac output decreased from 19.1% +/- 12.5% to 15.5% +/- 8.8% (P < 0.05), and renal vascular resistance index increased from 11762 +/- 6554 dynes. s. cm(-)(5). m(2) to 15078 +/- 10594 dynes. s. cm(-)(5). m(2) (P < 0.05), whereas effective renal blood flow index, glomerular filtration rate index, filtration fraction, urine volume, fractional sodium excretion, and osmolar and free water clearances remained constant during prone positioning. Prone positioning, when used in patients with acute lung injury, although it is associated with a small increase in IAP, contributes to improved arterial oxygenation and systemic blood flow without affecting renal perfusion and function. Apparently, special support to allow free chest and abdominal movement seems unnecessary when mechanically ventilated, hemodynamically stable patients without abdominal hypertension are proned to improve gas exchange. IMPLICATIONS: Prone positioning is increasingly used to improve gas exchange in patients with acute lung injury. However, during prone positioning an increase in intraabdominal pressure in these critically ill patients may promote dysfunction of other organs. Therefore, we performed a randomized study in mechanically ventilated patients with acute lung injury to investigate the cardiovascular and renal effects of prone positioning.

Abdomen↗
PubMed2001

Cardiorespiratory effects of automatic tube compensation during airway pressure release ventilation in patients with acute lung injury.

BACKGROUND: Spontaneous breaths during airway pressure release ventilation (APRV) have to overcome the resistance of the artificial airway. Automatic tube compensation provides ventilatory assistance by increasing airway pressure during inspiration and lowering airway pressure during expiration, thereby compensating for resistance of the artificial airway. The authors studied if APRV with automatic tube compensation reduces the inspiratory effort without compromising cardiovascular function, end-expiratory lung volume, and gas exchange in patients with acute lung injury. METHODS: Fourteen patients with acute lung injury were breathing spontaneously during APRV with or without automatic tube compensation in random order. Airway pressure, esophageal and abdominal pressure, and gas flow were continuously measured, and tracheal pressure was estimated. Transdiaphragmatic pressure time product was calculated. End-expiratory lung volume was determined by nitrogen washout. The validity of the tracheal pressure calculation was investigated in seven healthy ventilated pigs. RESULTS: Automatic tube compensation during APRV increased airway pressure amplitude from 7.7+/-1.9 to 11.3+/-3.1 cm H2O (mean +/- SD; P < 0.05) while decreasing trans-diaphragmatic pressure time product from 45+/-27 to 27+/-15 cm H2O x s(-1) x min(-1) (P < 0.05), whereas tracheal pressure amplitude remained essentially unchanged (10.3+/-3.5 vs. 10.1+/-3.5 cm H2O). Minute ventilation increased from 10.4+/-1.6 to 11.4+/-1.5 l/min (P < 0.001), decreasing arterial carbon dioxide tension from 52+/-9 to 47+/-6 mmHg (P < 0.05) without affecting arterial blood oxygenation or cardiovascular function. End-expiratory lung volume increased from 2,806+/-991 to 3,009+/-994 ml (P < 0.05). Analysis of tracheal pressure-time curves indicated nonideal regulation of the dynamic pressure support during automatic tube compensation as provided by a standard ventilator. CONCLUSION: In the studied patients with acute lung injury, automatic tube compensation markedly unloaded the inspiratory muscles and increased alveolar ventilation without compromising cardiorespiratory function and end-expiratory lung volume.

Adult↗
PubMed2000

Effects of mechanical ventilation on release of cytokines into systemic circulation in patients with normal pulmonary function.

BACKGROUND: Mechanical ventilation with high tidal volumes (V(T)) in contrast to mechanical ventilation with low V(T) has been shown to increase plasma levels of proinflammatory and antiinflammatory mediators in patients with acute lung injury. The authors hypothesized that, in patients without previous lung injury, a conventional potentially injurious ventilatory strategy with high V(T) and zero end-expiratory pressure (ZEEP) will not cause a cytokine release into systemic circulation. METHODS: A total of 39 patients with American Society of Anesthesiologists physical status I-II and without signs of systemic infection scheduled for elective surgery with general anesthesia were randomized to receive mechanical ventilation with either (1) V(T) = 15 ml/kg ideal body weight on ZEEP, (2) V(T) = 6 ml/kg ideal body weight on ZEEP, or (3) V(T) = 6 ml/kg ideal body weight on positive end-expiratory pressure of 10 cm H2O. Plasma levels of proinflammatory and antiinflammatory mediators tumor necrosis factor, interleukin (IL)-6, IL-10, and IL-1 receptor antagonist were determined before and 1 h after the initiation of mechanical ventilation. RESULTS: Plasma levels of all cytokines remained low in all settings. IL-6, tumor necrosis factor, and IL-1 receptor antagonist did not change significantly after 1 h of mechanical ventilation. IL-10 was below the detection limit (10 pg/ml) in 35 of 39 patients. There were no differences between groups. CONCLUSIONS: Initiation of mechanical ventilation for 1 h in patients without previous lung injury caused no consistent changes in plasma levels of studied mediators. Mechanical ventilation with high V(T) on ZEEP did not result in higher cytokine levels compared with lung-protective ventilatory strategies. Previous lunge damage seems to be mandatory to cause an increase in plasma cytokines after 1 h of high V(T) mechanical ventilation.

Adult↗
PubMed1999

Severe accidental hypothermia: rewarming strategy using a veno-venous bypass system and a convective air warmer.

OBJECTIVE: To study a rewarming strategy for patients with severe accidental hypothermia using a simple veno-venous bypass in combination with a convective air warmer. SETTING: Eighteen beds in a university hospital intensive care unit. PATIENTS: Four adults admitted with a core temperature less than 30 degrees C. Hypothermia was caused by alcoholic intoxication in three patients and by drug overdose in one patient. MEASUREMENTS AND MAIN RESULTS: All patients were rewarmed by a venovenous bypass and in three cases a convective air warmer was also used. At a bypass flow rate of 100-300 ml/min the mean increase in core temperature was 1.15 degrees C/h (Range: 1.1-1.2 degrees C/h). One patient died 2 days after rewarming as a consequence of a reactivated pancreatitis. The other three patients survived without neurological sequelae. CONCLUSION: This rewarming technique seems safe and effective and allowed the controlled rewarming of our patients who suffered from severe accidental hypothermia

Adult↗
PubMed1999

Proportional assist versus pressure support ventilation: effects on breathing pattern and respiratory work of patients with chronic obstructive pulmonary disease.

OBJECTIVE: To investigate the breathing pattern and the inspiratory work of breathing (WOB(I)) in patients with chronic obstructive pulmonary disease (COPD) assisted with proportional assist ventilation (PAV) and conventional pressure support ventilation (PSV). DESIGN: Prospective controlled study. SETTING: Intensive care unit of a university hospital. PATIENTS: Thirteen COPD patients being weaned from mechanical ventilation. INTERVENTIONS: All patients were breathing PSV and two different levels of PAV. MEASUREMENTS AND MAIN RESULTS: During PAV (EVITA 2 prototype, Dräger, Germany), the resistance of the endotracheal tube (R(et)) was completely compensated while the patients' resistive and elastic loads were compensated for by approximately 80 % and 50 % (PAV(80) and PAV(50)), respectively. PSV was adjusted to match the same mean inspiratory pressure (Pinsp(mean)) as during PAV(80). Airway pressure, esophageal pressure and gas flow were measured over a period of 5 min during each mode. Neuromuscular drive (P(0.1)) was determined by inspiratory occlusions. Mean tidal volume (V(T)) was not significantly different between the modes. However, the coefficient of variation of V(T) was 10 +/- 4.%, 20 +/- 13 % and 15 +/- 8 % during PSV, PAV(80) and PAV(50), respectively. Respiratory rate (RR) and minute ventilation (V(E)) were significantly lower during PAV(80) as compared with both other modes, but the differences did not exceed 10 %. PAV(80) and PSV had comparable effects on WOB(I) and P(0.1), whereas WOB(I) and P(0.1) increased during PAV(50) compared with both other modes. CONCLUSION: Mean values of breathing pattern did not differ by a large amount between the investigated modes. However, the higher variability of V(T) during PAV indicates an increased ability of the patients to control V(T) in response to alterations in respiratory demand. A reduction in assist during PAV(50) resulted in an increase in WOB and indices of patient effort.

Aged↗
PubMed1998

Determination of functional residual capacity (FRC) by multibreath nitrogen washout in a lung model and in mechanically ventilated patients. Accuracy depends on continuous dynamic compensation for changes of gas sampling delay time.

OBJECTIVE: Validation of an open-circuit multibreath nitrogen washout technique (MBNW) for measurement of functional residual capacity (FRC). The accuracy of FRC measurement with and without continuous viscosity correction of mass spectrometer delay time (TD) relative to gas flow signal and the influence of baseline FIO2 was investigated. DESIGN: Laboratory study and measurements in mechanically ventilated patients. SETTING: Experimental laboratory and anesthesiological intensive care unit of a university hospital. PATIENTS: 16 postoperative patients with normal pulmonary function (NORM), 8 patients with acute lung injury (ALI) and 6 patients with chronic obstructive pulmonary disease (COPD) were included. INTERVENTIONS: Change of FIO2 from baseline to 1.0. MEASUREMENTS AND MAIN RESULTS: FRC was determined by MBNW using continuous viscosity correction of TD(TDdyn), a constant TD based on the viscosity of a calibration gas mixture (TD0) and a constant TD referring to the mean viscosity between onset and end of MBNW (TDmean). Using TDdyn, the mean deviation between 15 measurements of three different lung model FRCs (FRCmeasured) and absolute volumes (FRCmodel) was 0.2%. For baseline FIO2 ranging from 0.21 to 0.8, the mean deviation between FRCmeasured and FRCmodel was -0.8%. However, depending on baseline FIO2, the calculation of FRC using TDmean and TD0 increased the mean deviation between FRCmeasured and FRCmodel to 2-4% and 8-12%, respectively. In patients (n = 30) the average repeatability coefficient was 6.0%. FRC determinations with TDmean and TD0 were 0.8-13.3% and 4.2-23.9% (median 2.7% and 8.7%) smaller than those calculated with TDdyn. CONCLUSION: A dynamic viscosity correction of TD improves the accuracy of FRC determinations by MBNW considerably, when gas concentrations are measured in a sidestream. If dynamic TD correction cannot be performed, the use of constant TDmean might be suitable. However, in patient measurements this can cause an FRC underestimation of up to 13%.

Adult↗