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Diederik Gommers

Publications and source records attributed to Diederik Gommers.

10 recordsLinked to original sources
PubMed2006

The effect of open lung ventilation on right ventricular and left ventricular function in lung-lavaged pigs.

INTRODUCTION: Ventilation according to the open lung concept (OLC) consists of recruitment maneuvers, followed by low tidal volume and high positive end-expiratory pressure, aiming at minimizing atelectasis. The minimization of atelectasis reduces the right ventricular (RV) afterload, but the increased intrathoracic pressures used by OLC ventilation could increase the RV afterload. We hypothesize that when atelectasis is minimized by OLC ventilation, cardiac function is not affected despite the higher mean airway pressure. METHODS: After repeated lung lavage, each pig (n = 10) was conventionally ventilated and was ventilated according to OLC in a randomized cross-over setting. Conventional mechanical ventilation (CMV) consisted of volume-controlled ventilation with 5 cmH2O positive end-expiratory pressure and a tidal volume of 8-10 ml/kg. No recruitment maneuvers were performed. During OLC ventilation, recruitment maneuvers were applied until PaO2/FiO2 > 60 kPa. The peak inspiratory pressure was set to obtain a tidal volume of 6-8 ml/kg. The cardiac output (CO), the RV preload, the contractility and the afterload were measured with a volumetric pulmonary artery catheter. A high-resolution computed tomography scan measured the whole lung density and left ventricular (LV) volumes. RESULTS: The RV end-systolic pressure-volume relationship, representing RV afterload, during steady-state OLC ventilation (2.7 +/- 1.2 mmHg/ml) was not significantly different compared with CMV (3.6 +/- 2.5 mmHg/ml). Pulmonary vascular resistance (OLC, 137 +/- 49 dynes/s/cm5 versus CMV, 130 +/- 34 dynes/s/cm5) was comparable between groups. OLC led to a significantly lower amount of atelectasis (13 +/- 2% of the lung area) compared with CMV (52 +/- 3% of the lung area). Atelectasis was not correlated with pulmonary vascular resistance or end-systolic pressure-volume relationship. The LV contractility and afterload during OLC was not significantly different compared with CMV. Compared with baseline, the LV end-diastolic volume (66 +/- 4 ml) decreased significantly during OLC (56 +/- 5 ml) ventilation and not during CMV (61 +/- 3 ml). Also, CO was significantly lower during OLC ventilation (OLC, 4.1 +/- 0.3 l/minute versus CMV, 4.9 +/- 0.3 l/minute). CONCLUSION: In this experimental study, OLC resulted in significantly improved lung aeration. Despite the use of elevated airway pressures, no evidence was found for a negative effect of OLC on RV afterload or LV afterload, which might be associated with a loss of hypoxic pulmonary vasoconstriction due to alveolar recruitment. The reductions in the CO and in the mean pulmonary artery pressure were consequences of a reduced preload.

Animals↗
PubMed2006

Open lung ventilation does not increase right ventricular outflow impedance: An echo-Doppler study.

OBJECTIVE: Ventilation according to the open lung concept (OLC) consists of recruitment maneuvers, followed by low tidal volume and elevated positive end-expiratory pressure (PEEP). Elevated PEEP is associated with an increased right ventricular afterload. We investigated the effect of OLC ventilation on right ventricular outflow impedance during inspiration and expiration in patients after cardiac surgery using transesophageal echo-Doppler. DESIGN: A prospective, single-center, crossover, randomized, controlled clinical study. SETTING: Cardiothoracic intensive care unit of a university hospital. PATIENTS: Twenty-eight patients scheduled for elective cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: In the intensive care unit, each patient was ventilated for approximately 30 mins according to both OLC and conventional ventilation. During OLC ventilation, recruitment maneuvers were applied until PaO2/FiO2 was >375 torr (50 kPa); during conventional ventilation no recruitment maneuvers were performed. MEASUREMENTS AND MAIN RESULTS: Transesophageal echo-Doppler measurements were performed at end-inspiration and end-expiration in a steady-state condition, 20 mins after initiation of a ventilation strategy. Mean acceleration of flow was determined in the long axis of the pulmonary artery in a transverse axis view. During OLC ventilation, a total PEEP of 14 +/- 4 cm H2O was applied vs. 5 cm H2O during conventional ventilation. Mean acceleration during expiration was comparable between groups. During inspiration, OLC ventilation did not cause a decrease of mean acceleration compared with expiration, whereas this did occur during conventional ventilation. CONCLUSIONS: Despite the use of elevated PEEP levels, ventilation according to OLC does not change right ventricular outflow impedance during expiration and decreases right ventricular outflow impedance during inspiration.

Blood Flow Velocity↗
PubMed2006

Intravenous nitroglycerin does not preserve gastric microcirculation during gastric tube reconstruction: a randomized controlled trial.

INTRODUCTION: Complications of oesophagectomy and gastric tube reconstruction include leakage and stenosis, which may be due to compromised microvascular blood flow (MBF) in gastric tissue. We recently demonstrated that decreased MBF could be improved perioperatively by topical administration of nitroglycerin. The aim of the present study was to investigate whether nitroglycerin, administered intravenously during gastric tube reconstruction, could preserve tissue blood flow and oxygenation in the gastric fundus, and reduce the incidence of postoperative leakage. METHODS: In this single-centre, prospective, double-blinded study, we randomized 32 patients scheduled for oesophagectomy into two groups. The intervention group received intravenous nitroglycerin during gastric tube reconstruction, and the control group received normal saline. Baseline values for MBF, microvascular haemoglobin oxygen saturation and microvascular haemoglobin concentration were determined at the gastric fundus before and after gastric tube construction and after pulling up the gastric tube to the neck. RESULTS: MBF and microvascular haemoglobin oxygen saturation decreased similarly in both groups during gastric tube reconstruction and were comparable. The oesophageal anastomosis was controlled by contrast radiography before discharge from the hospital; leakage was observed in two patients (13%) in the nitroglycerin group and five patients (31%) in the control group (not significant). CONCLUSION: Under stable systemic haemodynamic conditions, continuous intravenous administration of nitroglycerin could not prevent deterioration in gastric microvascular perfusion and microvascular haemoglobin saturation during gastric tube reconstruction.

Aged↗
PubMed2005

Ventilation according to the open lung concept attenuates pulmonary inflammatory response in cardiac surgery.

OBJECTIVE: Cardiac surgery with cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response, which is correlated with outcome. We hypothesized that ventilation according to the open lung concept (OLC) attenuates cytokine release. METHODS: A prospective, single center randomized controlled clinical study containing 62 patients scheduled for elective coronary artery bypass graft and/or valve surgery with cardiopulmonary bypass. Before surgery, patients were randomly assigned to three groups: (1) conventional mechanical ventilation (CV), (2) OLC started after arrival on the ICU (late open lung, LOL), and (3) OLC started directly after intubation (early open lung, EOL). In both OLC groups, recruitment maneuvers were applied until PaO(2)/FiO(2)>50. The CV group received no recruitment maneuvers. Interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma were measured preoperatively, immediately after cessation of CPB, and 3h, 5h, 24h, 2, and 3 days after cessation of CPB. RESULTS: CPB caused a significant increase of IL-6, IL-8, and IL-10 in all groups. Thereafter, IL-8 decreased significantly more rapidly in both OLC groups compared to CV. IL-10 decreased significantly more rapidly after CPB only in the EOL group, compared with CV. Three hours after cessation of the CPB, IL-10 was already comparable with preoperative levels in the EOL group, but not in the LOL or CV group. IL-6, TNF-alpha, and IFN-gamma did not differ significantly between groups. CONCLUSIONS: OLC ventilation leads to an attenuated inflammatory response, presumably by reducing additional lung injury after cardiac surgery. Studies on cytokines after cardiac surgery should take these findings into account.

Aged↗
PubMed2005

Open lung ventilation improves functional residual capacity after extubation in cardiac surgery.

OBJECTIVE: After cardiac surgery, functional residual capacity (FRC) after extubation is reduced significantly. We hypothesized that ventilation according to the open lung concept (OLC) attenuates FRC reduction after extubation. DESIGN: A prospective, single-center, randomized, controlled clinical study. SETTING: Cardiothoracic operating room and intensive care unit of a university hospital. PATIENTS: Sixty-nine patients scheduled for elective coronary artery bypass graft and/or valve surgery with cardiopulmonary bypass. INTERVENTIONS: Before surgery, patients were randomly assigned to three groups: (1) conventional ventilation (CV); (2) OLC, started after arrival in the intensive care unit (late open lung); and (3) OLC, started directly after intubation (early open lung). In both OLC groups, recruitment maneuvers were applied until Pao2/Fio2 was >375 Torr (50 kPa). No recruitment maneuvers were applied in the CV group. MEASUREMENTS AND MAIN RESULTS: FRC was measured preoperatively and 1, 3, and 5 days after extubation. Peripheral hemoglobin saturation (Spo2) was measured daily till the third day after extubation while the patient was breathing room air. Hypoxemia was defined by an Spo2 value < or =90%. Averaged over the 5 postoperative days, FRC was significantly higher in the early open lung group and tended to be higher in the late open lung group, in comparison with the CV group (mean +/- sem: CV, 1.8 +/- 0.1; late open lung,1.9 +/- 0.1; and early open lung, 2.2 +/- 0.1l). In the CV group, 37% of the patients were hypoxic on the third day after extubation, compared with none of the patients in both OLC groups. CONCLUSIONS: After cardiac surgery, earlier application of OLC resulted in a significantly higher FRC and fewer episodes of hypoxemia than with CV after extubation.

Adult↗
PubMed2005

The effect of nitroglycerin on microvascular perfusion and oxygenation during gastric tube reconstruction.

Esophagectomy followed by gastric tube reconstruction is the surgical treatment of choice for patients with esophageal cancer. Complications of the cervical anastomosis are associated with impaired microvascular blood flow (MBF) and ischemia in the gastric fundus. The aim of the present study was to differentiate whether the decrease in MBF is a result of arterial insufficiency or of venous congestion. To do this we assessed MBF, microvascular hemoglobin oxygen saturation (muHbSo(2)), and microvascular hemoglobin concentration (muHbcon) simultaneously during different stages of gastric tube reconstruction. In 14 patients, MBF was determined with laser Doppler flowmetry, and muHbSo(2) and muHbcon were determined with reflectance spectro- photometry. After completion of the anastomosis, nitroglycerin was applied at the fundus. Although MBF did not change significantly in the pylorus, MBF decreased progressively during surgery in the fundus from 210 +/- 18 Arbitrary Units at baseline (normal stomach) to 52 +/- 9 Arbitrary Units after completion of reconstruction (mean +/- sem; P < 0.05). There was no change in muHbSo(2) and muHbcon during the reconstruction. After application of nitroglycerin, MBF doubled. We conclude that MBF decreases during gastric tube reconstruction but that muHbSo(2) and muHbcon do not. This decrease might be the result of venous congestion, which can partly be counteracted by application of nitroglycerin.

Adult↗
PubMed2003

Effects of simultaneous aortocaval occlusion on oxygen consumption in patients.

The effects of simultaneous occlusion of the thoracic aorta and inferior vena cava on oxygen consumption (V O 2) have not yet been reported in humans. Ten patients (all ASA II) needed such simultaneous occlusion to allow hypoxic abdominal perfusion in the treatment of pancreatic cancer. With the development of the PhysioFlex anaesthesia machine for closed-circuit anaesthesia, intra-operative real-time curves of V O 2 became available. Thus, we can continuously measure F I O 2, V E, V O 2, and air consumption. By placing a pulmonary artery catheter, we could also intermittently calculate D O 2 during the several phases of the perfusion procedure. Immediately after the simultaneous aortocaval occlusion started, V O 2 decreased by 35% (68 ml min-1 m-2) and D O 2 decreased below the critical value of 330 ml min-1 m-2. At reperfusion, repayment of the oxygen debt was by a two-stage pattern: a fast repayment stage with an increase of about 65% was followed by a slow repayment stage of 14% increase (values compared to steady state). Oxygen consumption in women was found to be significantly lower than in men (P = 0.02), with significant variation between the sexes during different stages of the procedure. The oxygen debt was not completely repaid by the end of the procedure. We conclude that the significant variation found in oxygen consumption will have consequences while performing low-flow anaesthesia, that additional oxygen supply during the recovery period because of the initially incomplete repayment of oxygen debt may be useful and that studies on oxygen consumption must present gender-specific data because of the gender-dependent variation found in oxygen consumption.

Antineoplastic Agents↗
PubMed2002

Antidiuretic hormone release during laparoscopic donor nephrectomy.

BACKGROUND: During laparoscopic procedures, increased intra-abdominal pressure may cause transient renal dysfunction due to impaired renal blood flow and induction of neurohormones. However, the relationship between antidiuretic hormone (ADH) secretion and increased intra-abdominal pressure is poorly understood. HYPOTHESIS: Laparoscopic donor nephrectomy (LDN) is associated with an increase in plasma ADH concentration, which influences renal function in both the donor and transplanted graft. OBJECTIVES: To evaluate plasma ADH levels during LDN and to correlate ADH levels with graft function. DESIGN AND INTERVENTIONS: In 30 patients who underwent LDN, plasma ADH levels were collected before insufflation, during surgery, after desufflation, and 24 hours after the procedure. In 6 patients who had open donor nephrectomy, blood samples were obtained as controls. Furthermore, graft function, operative characteristics, and clinical outcome were compared. SETTING: University hospital. RESULTS: In the LDN group, mean ADH levels during pneumoperitoneum and 30 minutes postinsufflation were significantly higher compared with preinsufflation values (P<.001). Twenty-four hours after LDN, mean ADH levels had returned to normal values. There were no significant differences in ADH levels in the open donor nephrectomy group. No significant differences in either intraoperative diuresis, blood pressure readings, or postoperative graft function were documented among the 2 groups. CONCLUSIONS: In this study, LDN was associated with an increase in plasma ADH that appeared to be related to increased intra-abdominal pressure. We conclude that the increased ADH concentrations during LDN are not associated with clinically significant changes in either the kidney donor or the transplanted graft.

Adult↗
PubMed2002

Impact of intraoperative donor management on short-term renal function after laparoscopic donor nephrectomy.

OBJECTIVE: To determine whether intraoperative diuresis, postoperative recovery, and early graft function differ between laparoscopic open nephrectomy (LDN) and open donor nephrectomy (ODN). SUMMARY BACKGROUND DATA: Laparoscopic donor nephrectomy can reduce donor complications in terms of decreased pain and shorter convalescence. Although its technical feasibility has been established, concerns have been raised about the impaired renal function resulting from pneumoperitoneum and short- and long-term function of kidneys removed by LDN. METHODS: Between December 1997 and December 2000, 89 LDNs were performed at the authors' institution. These were compared with 83 conventional ODNs performed between January 1994 and December 1997. Graft function, intraoperative variables, and clinical outcome were compared. RESULTS: Laparoscopic donor nephrectomy was attempted in 89 patients and completed in 91% (81/89). Length of hospital stay was significantly shorter in the laparoscopic group. During kidney dissection, the amount of fluids administered and intraoperative diuresis were significantly lower for LDN. In recipients, mean serum creatinine was higher after LDN compared with ODN 1 day after surgery. From postoperative days 2 until 28, there were no differences in serum creatinine. Graft survival rates were similar for LDN and ODN. CONCLUSIONS: Donors can benefit from an improvement in postoperative recovery after LDN. Assessment of an adequate perioperative hydration protocol is mandatory to ensure optimal kidney quality during laparoscopic procurement. The initial graft survival and function rates justify continued development and adoption of LDN.

Adult↗