Flow-related techniques for preoperative goal-directed fluid optimization
ABSTRACT Improved postoperative outcome has been demonstrated by perioperative maximization of cardiac stroke volume (SV) with fluid challenges, so-called goal-directed therapy. Oesophageal Doppler (OD) has been the most common technique for goal-directed therapy, but other flow-related techniques and parameters are available and they are potentially easier to apply in clinical practice. The objective of this investigation was therefore to use OD for preoperative SV maximization and compare the findings with a Modelflow determined SV, with an OD estimated corrected flow time (FTc), with central venous oxygenation ( Svo2 ) and with muscle and brain oxygenation assessed with near infrared spectroscopy (NIRS).
Twelve patients scheduled for radical prostatectomy were anaesthetized before optimization of SV estimated by OD. A fluid challenge of 200 ml colloid was provided and repeated if at least a 10% increment in OD SV was obtained. Values were compared with simultaneously measured values of Modelflow SV, FTc, Svo2 and muscle and cerebral oxygenation estimated by NIRS.
Based upon OD assessment, optimization of SV was achieved after the administration of 400-800 ml (mean 483 ml) of colloid. The hypothetical volumes administered for optimization based upon Modelflow and Svo2 differed from OD in 10 and 11 patients, respectively. Changes in FTc and NIRS were inconsistent with OD guided optimization.
Preoperative SV optimization guided by OD for goal-directed therapy is preferable compared with Modelflow SV, FTc, NIRS and Svo2 until outcome studies for the latter are available.
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ABSTRACT: Patients with limited cardiopulmonary reserve are at risk of mortality and morbidity after major surgery. Augmentation of oxygen delivery index (DO2I) with i.v. fluids and inotropes (goal-directed therapy, GDT) has been shown to reduce postoperative mortality and morbidity in high-risk patients. Concerns regarding cardiac complications associated with fluid challenges and inotropes may prevent clinicians from performing GDT in patients who need it most. We hypothesized that GDT is not associated with an increased risk of cardiac complications in high-risk, non-cardiac surgical patients. We performed a systematic search of Medline, Embase, and CENTRAL databases for randomized controlled trials (RCTs) of GDT in high-risk surgical patients. Studies including cardiac surgery, trauma, and paediatric surgery were excluded. We reviewed the rates of all cardiac complications, arrhythmias, myocardial ischaemia, and acute pulmonary oedema. Meta-analyses were performed using RevMan software. Data are presented as odds ratios (ORs), [95 confidence intervals (CIs)], and P-values. Twenty-two RCTs including 2129 patients reported cardiac complications. GDT was associated with a reduction in total cardiovascular (CVS) complications [OR0.54, (0.380.76), P0.0005] and arrhythmias [OR0.54, (0.350.85), P0.007]. GDT was not associated with an increase in acute pulmonary oedema [OR0.69, (0.431.10), P0.12] or myocardial ischaemia [OR0.70, (0.381.28), P0.25]. Subgroup analysis revealed the benefit is most pronounced in patients receiving fluid and inotrope therapy to achieve a supranormal DO2I, with the use of minimally invasive cardiac output monitors. Treatment of high-risk surgical patients GDT is not associated with an increased risk of cardiac complications; GDT with fluids and inotropes to optimize DO2I during early GDT reduces postoperative CVS complications.BJA British Journal of Anaesthesia 01/2014; 112(4). DOI:10.1093/bja/aet466 · 4.35 Impact Factor
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ABSTRACT: /st>Phenylephrine and ephedrine affect frontal lobe oxygenation () differently when assessed by spatially resolved near infrared spectroscopy. We evaluated the effect of phenylephrine and ephedrine on extra- vs intra-cerebral blood flow and on . /st>In 10 healthy males (age 20-54 yr), phenylephrine or ephedrine was infused for an ∼20 mm Hg increase in mean arterial pressure. Cerebral oxygenation (SavO2) was calculated from the arterial and jugular bulb oxygen saturations. Blood flow in the internal carotid artery (ICAf) and blood flow in the external carotid artery (ECAf) were assessed by duplex ultrasonography. Invos-5100c (SinvosO2) and Foresight (SforeO2) determined while forehead skin oxygenation (SskinO2) was assessed. /st>Phenylephrine reduced SforeO2 by 6.9% (95% confidence interval: 4.8-9.0%; P<0.0001), SinvosO2 by 10.5 (8.2-12.9%; P<0.0001), and ECAf (6-28%; P=0.0001), but increased ICAf (5-21%; P=0.003) albeit with no consequence for SskinO2 or SavO2. In contrast, SforeO2 was maintained with administration of ephedrine while SinvosO2 and SavO2 decreased [by 3.1 (0.7-4.5%; P=0.017) and 2.1 (0.5-3.3%; P=0.012)] as arterial carbon dioxide pressure decreased (P=0.003). ICAf was stable and ECAf increased by 11 (4-18%; P=0.005) with administration of ephedrine while SskinO2 did not change. /st>The effect of phenylephrine on is governed by a decrease in external carotid blood flow since it increases cerebral blood flow as determined by flow in the internal carotid artery. In contrast, is largely maintained with administration of ephedrine because blood flow to extracerebral tissue increases.BJA British Journal of Anaesthesia 02/2014; 113(3). DOI:10.1093/bja/aet481 · 4.35 Impact Factor
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ABSTRACT: Near-infrared spectroscopy (NIRS) is used to monitor regional cerebral oxygenation (rScO2) during cardiac surgery but is less established during non-cardiac surgery. This systematic review aimed (i) to determine the non-cardiac surgical procedures that provoke a reduction in rScO2 and (ii) to evaluate whether an intraoperative reduction in rScO2 influences postoperative outcome. The PubMed and Embase database were searched from inception until April 30, 2013 and inclusion criteria were intraoperative NIRS determined rScO2 in adult patients undergoing non-cardiac surgery. The type of surgery and number of patients included were recorded. There was included 113 articles and evidence suggests that rScO2 is reduced during thoracic surgery involving single lung ventilation, major abdominal surgery, hip surgery, and laparoscopic surgery with the patient placed in anti-Tredelenburg's position. Shoulder arthroscopy in the beach chair and carotid endarterectomy with clamped internal carotid artery (ICA) also cause pronounced cerebral desaturation. A >20% reduction in rScO2 coincides with indices of regional and global cerebral ischemia during carotid endarterectomy. Following thoracic surgery, major orthopedic, and abdominal surgery the occurrence of postoperative cognitive dysfunction (POCD) might be related to intraoperative cerebral desaturation. In conclusion, certain non-cardiac surgical procedures is associated with an increased risk for the occurrence of rScO2. Evidence for an association between cerebral desaturation and postoperative outcome parameters other than cognitive dysfunction needs to be established.Frontiers in Physiology 03/2014; 5:93. DOI:10.3389/fphys.2014.00093