Randomised controlled trial assessing the impact of a nurse delivered, flow monitored protocol for optimisation of circulatory status after
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《英国医生杂志》
1 Bloomsbury Institute of Intensive Care Medicine, Department of Medicine and Wolfson Institute of Biomedical Research, University College London, Middlesex Hospital, London W1T 3AA, 2 Intensive Care National Audit and Research Centre, BMA House, London WC1H 9JR
Correspondence to: M Singer m.singer@ucl.ac.uk
Abstract
Hypovolaemia and tissue hypoperfusion can pass undetected during and after major surgery.1 The resulting systemic inflammatory response and organ dysfunction, often not clinically apparent for several days, may lead to increased morbidity and mortality and prolonged hospital stay.
Several perioperative studies have used invasive (pulmonary artery catheterisation) or minimally invasive (oesophageal Doppler flowmetry) monitoring technologies to optimise circulatory variables such as stroke volume, cardiac output, arterial lactate concentration, or oxygen delivery and consumption.2 Although a similar approach proved unsuccessful in improving outcomes in critically ill patients with organ failure, these studies showed major improvements in postoperative complications and stay in intensive care or hospital. By comparison, a recent Canadian study found no improvement in outcomes in patients allocated to pulmonary artery catheterisation but in whom a protocol for haemodynamic optimisation was not followed perioperatively.3
To our knowledge, only one randomised study (403 patients) has specifically investigated optimisation of circulatory status after cardiac surgery.4 This study reported a reduction in median duration of hospital stay from seven to six days (P < 0.05) in patients targeted to achieve a mixed venous saturation in excess of 70% and a plasma lactate concentration below 2 mmol/l in the first eight hours postoperatively. We previously reported that a low stroke volume index (< 35 ml/m2) and a high heart rate on admission to intensive care after cardiac surgery and at four hours were the best prognostic factors for the development of subsequent complications.5 We therefore studied the optimisation of circulatory status in patients in the first four hours after admission to intensive care after cardiac surgery. Half the patients were randomised to receive treatment (fluid with or without vasodilators and inotropes) guided by oesophageal Doppler flowmetry to achieve a stroke volume index above 35 ml/m2. This trial differs from the previous study in two major respects.4 Firstly, cardiac output was monitored using minimally invasive technology (oesophageal Doppler flowmetry) and, secondly, nurses conducted the study using a protocol driven approach with minimal additional input from medical staff.
Participants and methods
Overall, 179 patients were recruited between April 2000 and January 2003 (fig 2). Five patients who provided consent before surgery did not fulfil the postoperative entry criteria. Four of these five patients were erroneously randomised but are not included in subsequent analyses, leaving 89 patients in the protocol group and 85 in the control group. The groups were well matched for age, sex, weight, Parsonnet cardiac risk score, and type of surgery (table 1).7 The median first 24 hour acute physiological and chronic health evaluation II score was similar in both groups (10 protocol, 11 control). These patients are representative of the total cardiac surgical population of the hospital, whose Parsonnet score averaged 9.0 (SD 7.4), with a similar frequency of coronary artery bypass grafting with or without valve replacement.
Fig 2 Flow of participants through trial
Table 1 Baseline characteristics of patients randomised after cardiac surgery to conventional management or protocol for optimising cardiac variables. Values are numbers (percentages) unless stated otherwise
Table 2 shows the haemodynamic data and fluid requirements over the initial four hour postoperative period. Although stroke volume index, cardiac index, and use of colloid were well matched at baseline (within 10 minutes of admission), they were significantly greater in the protocol group at four hours; use of inotropes was similar between the two groups. Colloid was given to all but one of the control patients. None of the control patients had pulmonary artery catheters in situ or had Doppler probes placed because of perceived clinical need. Inotropes were not instituted as per protocol to increase stroke volume index values to 35 ml/m2 or greater owing to the short duration of the study and the frequent need for repeated fluid challenges in the study period. At four hours, 35 (39%) protocol patients and 48 (56%) control patients had values below 35 ml/m2.
Table 2 Management of patients in four hours after cardiac surgery. Values are means (standard deviations)
In the protocol group, the mean number of days in intensive care, although not statistically significant, was reduced from 3.2 to 2.5 (23% reduction, 95% confidence interval -8% to 59%; fig 3). The mean duration of hospital stay in this group was reduced from 13.9 to 11.4 days (18% reduction, -12% to 47%), with a significant reduction in median duration of stay from nine to seven days (P = 0.02). Delayed hospital discharge for non-medical reasons affected four protocol patients (total delay 23 days) and one control patient (three days).
Fig 3 Duration of stay in intensive care and hospital in patients receiving strategy to optimise circulatory status after cardiac surgery (protocol) or conventional management (control). Six hospital stays beyond 50 days not shown
Four deaths occurred in the protocol group and two in the control group, the causes of which were not considered directly attributable to early postoperative care (table 3). Comparisons of length of stay in survivors only were similar to those for all patients. The protocol group showed a trend towards fewer major postoperative complications and deaths than the control group (table 4).
Table 3 Details of deaths after cardiac surgery
Table 4 Number of patients with complications after cardiac surgery
Discussion
Shoemaker WC, Wo CC, Thangathurai D, Velmahos G, Belzberg H, Asensio JA, et al. Haemodynamic patterns of survivors and non survivors during high risk elective surgical operations. World J Surg 1999;23: 1264-70.
Kern JW, Shoemaker WC. Meta analysis of hemodynamic optimisation in high risk patients. Crit Care Med 2002;30: 1686-9.
Sandham JD, Hull RD, Brant RF, Knox L, Pineo GF, Doig CJ, et al. A randomised, controlled trial of the use of pulmonary artery catheters in high risk surgical patients. N Engl J Med 2003;348: 5-14.
Polonen P, Ruokonen E, Hippelainem M, Poyhonen M, Takala J. A prospective randomised study of goal oriented hemodynamic therapy in cardiac surgical patients. Anaesth Analg 2000;90: 1052-9.
Poeze M, Ramsay G, Greve JWM, Singer M. Prediction of post operative cardiac surgical morbidity and organ failure within 4 hours of ICU admission using esophageal Doppler ultrasonography. Crit Care Med 1999;27: 1288-94.
Thompson SG, Barber JA. How should cost data in pragmatic randomised trials be analysed? BMJ 2000;320: 1197-200.
Parsonnet V, Dean D, Bernstein AD. A method of uniform stratification of risk for evaluating the results of surgery in acquired adult heart disease. Circulation 1989;79: I3-12.
Mythen MG, Webb AR. Intra-operative gut mucosal hypoperfusion is associated with increased post-operative complications and cost. Intensive Care Med 1994;20: 99-104.
Shoemaker WC, Thangathurai D, Wo CC, Kuchta K, Canas M, Sullivan MJ, et al. Intra-operative evaluation of tissue perfusion in high-risk patients by invasive and noninvasive hemodynamic monitoring. Crit Care Med 1999;27: 2147-52.
Maillet JM, Le Besnerais P, Cantoni M, Nataf P, Ruffenach A, Lessana A, et al. Frequency, risk factors, and outcome of hyperlactatemia after cardiac surgery. Chest 2003;123: 1361-6.
Shoemaker WC, Appel PL, Kram HB. Role of oxygen debt in the development of organ failure sepsis, and death in high-risk surgical patients. Chest 1992;102: 208-15.
Welsby IJ, Bennett-Guerrero E, Atwell D, White WD, Newman MF, Smith PK, et al. The association of complication type with mortality and prolonged stay after cardiac surgery with cardiopulmonary bypass. Anesth Analg 2002;94: 1072-8.
Shoemaker WC, Appel PL, Kram HB, Waxman K, Lee TS. Prospective trial of supranormal values of survivors as therapeutic goals in high-risk surgical patients. Chest 1988;94: 1176-86.
Boyd O, Grounds RM, Bennett ED. A randomized clinical trial of the effect of deliberate perioperative increase of oxygen delivery on mortality in high-risk surgical patients. JAMA 1993;270: 2699-707.
Wilson J, Woods I, Fawcett J, Whall R, Dibb W, Morris C, et al. Reducing the risk of major elective surgery: randomised controlled trial of preoperative optimisation of oxygen delivery. BMJ 1999;318: 1099-103.
Polanczyk CA, Rohde LE, Goldman L, Cook EF, Thomas EJ, Marcantonio ER, et al. Right heart catheterization and cardiac complications in patients undergoing noncardiac surgery: an observational study. JAMA 2001;286: 309-14.
Mythen MG, Webb AR. Perioperative plasma volume expansion reduces the incidence of gut mucosal hypoperfusion during cardiac surgery. Arch Surg 1995;130: 423-9.
Sinclair S, James S, Singer M. Intraoperative intravascular volume optimisation and length of hospital stay after repair of proximal femoral fracture: randomised controlled trial. BMJ 1997;315: 909-12.
Gan TJ, Soppitt A, Maroof M, el-Moalem H, Robertson KM, Moretti E, et al. Goal-directed intraoperative fluid administration reduces length of hospital stay after major surgery. Anesthesiology 2002;97: 820-6.
Venn R, Steele A, Richardson P, Poloniecki J, Grounds M, Newman P. Randomized controlled trial to investigate influence of the fluid challenge on duration of hospital stay and perioperative morbidity in patients with hip fractures. Br J Anaesth 2002;88: 65-71.
Valtier B, Cholley BP, Belot JP, de la Coussaye JE, Mateo J, Payen DM. Noninvasive monitoring of cardiac output in critically ill patients using transesophageal Doppler. Am J Respir Crit Care Med 1998;158: 77-83.
Singer M, Bennett ED. Noninvasive optimization of left ventricular filling using esophageal Doppler. Crit Care Med 1991;19: 1132-7.
Singer M, Allen MJ, Webb AR, Bennett ED. Effects of alterations in left ventricular filling, contractility and systemic vascular resistance on the ascending aortic blood velocity waveform of normal subjects. Crit Care Med 1991;19: 1138-45.
Older P, Smith R, Courtney P, Hone R. Preoperative evaluation of cardiac failure and ischemia in elderly patients by cardiopulmonary exercise testing. Chest 1993;104: 701-4.(Moira McKendry, research )
Correspondence to: M Singer m.singer@ucl.ac.uk
Abstract
Hypovolaemia and tissue hypoperfusion can pass undetected during and after major surgery.1 The resulting systemic inflammatory response and organ dysfunction, often not clinically apparent for several days, may lead to increased morbidity and mortality and prolonged hospital stay.
Several perioperative studies have used invasive (pulmonary artery catheterisation) or minimally invasive (oesophageal Doppler flowmetry) monitoring technologies to optimise circulatory variables such as stroke volume, cardiac output, arterial lactate concentration, or oxygen delivery and consumption.2 Although a similar approach proved unsuccessful in improving outcomes in critically ill patients with organ failure, these studies showed major improvements in postoperative complications and stay in intensive care or hospital. By comparison, a recent Canadian study found no improvement in outcomes in patients allocated to pulmonary artery catheterisation but in whom a protocol for haemodynamic optimisation was not followed perioperatively.3
To our knowledge, only one randomised study (403 patients) has specifically investigated optimisation of circulatory status after cardiac surgery.4 This study reported a reduction in median duration of hospital stay from seven to six days (P < 0.05) in patients targeted to achieve a mixed venous saturation in excess of 70% and a plasma lactate concentration below 2 mmol/l in the first eight hours postoperatively. We previously reported that a low stroke volume index (< 35 ml/m2) and a high heart rate on admission to intensive care after cardiac surgery and at four hours were the best prognostic factors for the development of subsequent complications.5 We therefore studied the optimisation of circulatory status in patients in the first four hours after admission to intensive care after cardiac surgery. Half the patients were randomised to receive treatment (fluid with or without vasodilators and inotropes) guided by oesophageal Doppler flowmetry to achieve a stroke volume index above 35 ml/m2. This trial differs from the previous study in two major respects.4 Firstly, cardiac output was monitored using minimally invasive technology (oesophageal Doppler flowmetry) and, secondly, nurses conducted the study using a protocol driven approach with minimal additional input from medical staff.
Participants and methods
Overall, 179 patients were recruited between April 2000 and January 2003 (fig 2). Five patients who provided consent before surgery did not fulfil the postoperative entry criteria. Four of these five patients were erroneously randomised but are not included in subsequent analyses, leaving 89 patients in the protocol group and 85 in the control group. The groups were well matched for age, sex, weight, Parsonnet cardiac risk score, and type of surgery (table 1).7 The median first 24 hour acute physiological and chronic health evaluation II score was similar in both groups (10 protocol, 11 control). These patients are representative of the total cardiac surgical population of the hospital, whose Parsonnet score averaged 9.0 (SD 7.4), with a similar frequency of coronary artery bypass grafting with or without valve replacement.
Fig 2 Flow of participants through trial
Table 1 Baseline characteristics of patients randomised after cardiac surgery to conventional management or protocol for optimising cardiac variables. Values are numbers (percentages) unless stated otherwise
Table 2 shows the haemodynamic data and fluid requirements over the initial four hour postoperative period. Although stroke volume index, cardiac index, and use of colloid were well matched at baseline (within 10 minutes of admission), they were significantly greater in the protocol group at four hours; use of inotropes was similar between the two groups. Colloid was given to all but one of the control patients. None of the control patients had pulmonary artery catheters in situ or had Doppler probes placed because of perceived clinical need. Inotropes were not instituted as per protocol to increase stroke volume index values to 35 ml/m2 or greater owing to the short duration of the study and the frequent need for repeated fluid challenges in the study period. At four hours, 35 (39%) protocol patients and 48 (56%) control patients had values below 35 ml/m2.
Table 2 Management of patients in four hours after cardiac surgery. Values are means (standard deviations)
In the protocol group, the mean number of days in intensive care, although not statistically significant, was reduced from 3.2 to 2.5 (23% reduction, 95% confidence interval -8% to 59%; fig 3). The mean duration of hospital stay in this group was reduced from 13.9 to 11.4 days (18% reduction, -12% to 47%), with a significant reduction in median duration of stay from nine to seven days (P = 0.02). Delayed hospital discharge for non-medical reasons affected four protocol patients (total delay 23 days) and one control patient (three days).
Fig 3 Duration of stay in intensive care and hospital in patients receiving strategy to optimise circulatory status after cardiac surgery (protocol) or conventional management (control). Six hospital stays beyond 50 days not shown
Four deaths occurred in the protocol group and two in the control group, the causes of which were not considered directly attributable to early postoperative care (table 3). Comparisons of length of stay in survivors only were similar to those for all patients. The protocol group showed a trend towards fewer major postoperative complications and deaths than the control group (table 4).
Table 3 Details of deaths after cardiac surgery
Table 4 Number of patients with complications after cardiac surgery
Discussion
Shoemaker WC, Wo CC, Thangathurai D, Velmahos G, Belzberg H, Asensio JA, et al. Haemodynamic patterns of survivors and non survivors during high risk elective surgical operations. World J Surg 1999;23: 1264-70.
Kern JW, Shoemaker WC. Meta analysis of hemodynamic optimisation in high risk patients. Crit Care Med 2002;30: 1686-9.
Sandham JD, Hull RD, Brant RF, Knox L, Pineo GF, Doig CJ, et al. A randomised, controlled trial of the use of pulmonary artery catheters in high risk surgical patients. N Engl J Med 2003;348: 5-14.
Polonen P, Ruokonen E, Hippelainem M, Poyhonen M, Takala J. A prospective randomised study of goal oriented hemodynamic therapy in cardiac surgical patients. Anaesth Analg 2000;90: 1052-9.
Poeze M, Ramsay G, Greve JWM, Singer M. Prediction of post operative cardiac surgical morbidity and organ failure within 4 hours of ICU admission using esophageal Doppler ultrasonography. Crit Care Med 1999;27: 1288-94.
Thompson SG, Barber JA. How should cost data in pragmatic randomised trials be analysed? BMJ 2000;320: 1197-200.
Parsonnet V, Dean D, Bernstein AD. A method of uniform stratification of risk for evaluating the results of surgery in acquired adult heart disease. Circulation 1989;79: I3-12.
Mythen MG, Webb AR. Intra-operative gut mucosal hypoperfusion is associated with increased post-operative complications and cost. Intensive Care Med 1994;20: 99-104.
Shoemaker WC, Thangathurai D, Wo CC, Kuchta K, Canas M, Sullivan MJ, et al. Intra-operative evaluation of tissue perfusion in high-risk patients by invasive and noninvasive hemodynamic monitoring. Crit Care Med 1999;27: 2147-52.
Maillet JM, Le Besnerais P, Cantoni M, Nataf P, Ruffenach A, Lessana A, et al. Frequency, risk factors, and outcome of hyperlactatemia after cardiac surgery. Chest 2003;123: 1361-6.
Shoemaker WC, Appel PL, Kram HB. Role of oxygen debt in the development of organ failure sepsis, and death in high-risk surgical patients. Chest 1992;102: 208-15.
Welsby IJ, Bennett-Guerrero E, Atwell D, White WD, Newman MF, Smith PK, et al. The association of complication type with mortality and prolonged stay after cardiac surgery with cardiopulmonary bypass. Anesth Analg 2002;94: 1072-8.
Shoemaker WC, Appel PL, Kram HB, Waxman K, Lee TS. Prospective trial of supranormal values of survivors as therapeutic goals in high-risk surgical patients. Chest 1988;94: 1176-86.
Boyd O, Grounds RM, Bennett ED. A randomized clinical trial of the effect of deliberate perioperative increase of oxygen delivery on mortality in high-risk surgical patients. JAMA 1993;270: 2699-707.
Wilson J, Woods I, Fawcett J, Whall R, Dibb W, Morris C, et al. Reducing the risk of major elective surgery: randomised controlled trial of preoperative optimisation of oxygen delivery. BMJ 1999;318: 1099-103.
Polanczyk CA, Rohde LE, Goldman L, Cook EF, Thomas EJ, Marcantonio ER, et al. Right heart catheterization and cardiac complications in patients undergoing noncardiac surgery: an observational study. JAMA 2001;286: 309-14.
Mythen MG, Webb AR. Perioperative plasma volume expansion reduces the incidence of gut mucosal hypoperfusion during cardiac surgery. Arch Surg 1995;130: 423-9.
Sinclair S, James S, Singer M. Intraoperative intravascular volume optimisation and length of hospital stay after repair of proximal femoral fracture: randomised controlled trial. BMJ 1997;315: 909-12.
Gan TJ, Soppitt A, Maroof M, el-Moalem H, Robertson KM, Moretti E, et al. Goal-directed intraoperative fluid administration reduces length of hospital stay after major surgery. Anesthesiology 2002;97: 820-6.
Venn R, Steele A, Richardson P, Poloniecki J, Grounds M, Newman P. Randomized controlled trial to investigate influence of the fluid challenge on duration of hospital stay and perioperative morbidity in patients with hip fractures. Br J Anaesth 2002;88: 65-71.
Valtier B, Cholley BP, Belot JP, de la Coussaye JE, Mateo J, Payen DM. Noninvasive monitoring of cardiac output in critically ill patients using transesophageal Doppler. Am J Respir Crit Care Med 1998;158: 77-83.
Singer M, Bennett ED. Noninvasive optimization of left ventricular filling using esophageal Doppler. Crit Care Med 1991;19: 1132-7.
Singer M, Allen MJ, Webb AR, Bennett ED. Effects of alterations in left ventricular filling, contractility and systemic vascular resistance on the ascending aortic blood velocity waveform of normal subjects. Crit Care Med 1991;19: 1138-45.
Older P, Smith R, Courtney P, Hone R. Preoperative evaluation of cardiac failure and ischemia in elderly patients by cardiopulmonary exercise testing. Chest 1993;104: 701-4.(Moira McKendry, research )