Asian Cardiovasc Thorac Ann 2004;12:250-253
© 2004 Asia Publishing EXchange Ltd
What Influences the Results in Critical Patients After Cardiovascular Surgery?
Susumu Ishikawa, MD,
Tetsuya Koyano, MD,
Toru Takahashi, MD,
Yasushi Sato, MD,
Yutaka Hasegawa, MD,
Satoshi Ohki, MD,
Kiyohiro Oshima, MD,
Shigeru Oki, MD,
Fumio Kunimoto, MD1,
Yasuo Morishita, MD
Second Department of Surgery
1 Intensive Care Unit, Gunma University Hospital, Maebashi, Japan
For reprint information contact: Susumu Ishikawa, MD Tel: 81 27 220 8245 Fax: 81 27 220 8255 Email: skyishikawa{at}cronos.ocn.ne.jp Second Department of Surgery, Gunma University Faculty of Medicine, 1905–3 Showa-machi, Maebashi, Gunma 371–8511, Japan.
 |
ABSTRACT
|
|---|
The predictive factors of surgical outcome were evaluated in compromised patients following cardiovascular surgery. Of 608 patients undergoing cardiovascular surgery between 1991 and 1999, 55 stayed in the intensive care unit for 2 weeks or longer. The mean age of these 55 patients was 56 years. There were 35 survivors and 20 nonsurvivors. Postoperative respiratory failure and gastrointestinal complications were significantly more frequent in those who died. The survival rate was significantly higher in patients who had enteral feeding compared to those who did not (88% versus 43%). Serum cholinesterase and total cholesterol concentrations were higher in the survivors. It was concluded that postoperative respiratory and gastrointestinal conditions influenced the surgical outcome, and serum cholinesterase and total cholesterol concentrations were valuable predictors of survival.
|
INTRODUCTION
|
|---|
The period of intensive care unit (ICU) stay following cardiovascular surgery has been actively shortened due to the use of new anesthetic drugs, advances in operative techniques, and improved postoperative management.1–3 Prolonged postoperative ICU stay associated with morbidity sometimes results in a poor prognosis. The aim of this study was to investigate the predictive factors of surgical outcome in patients needing long-term ICU stay following cardiovascular surgery.
|
PATIENTS AND METHODS
|
|---|
Of 608 patients undergoing cardiovascular surgery between 1991 and 1999, 55 stayed in the ICU for 2 weeks or longer. The mean age of these 39 males and 16 females was 56 years, ranging from 3 to 81 years. Valve replacement was performed in 18 patients, coronary artery bypass grafting in 16, grafting of the thoracic aorta in 13, and radical correction of complex congenital heart diseases in 8. The patients were divided into two groups according to the operative outcome: the survivors (n = 35) and the nonsurvivors (n = 20). A membrane oxygenator and a roller pump were used to establish extracorporeal circulation, and moderate hypothermia was maintained during aortic crossclamping. Cold blood cardioplegia and topical cooling were used for myocardial protection during aortic crossclamping. The mean ages of the survivors and the nonsurvivors were 50 and 57 years, respectively. The survivors comprised of 26 males and 9 females; the nonsurvivors included 13 males and 7 females. There were no significant differences between the two groups in either surgical procedures or operative factors such as operation time, extracorporeal circulation time, aortic crossclamp time, and intraoperative volume overload (Table 1
). Values of hematological and biochemical tests on admission to the ICU were assessed as data before treatment (Table 2). Enteral feeding was tried in all patients as early as possible after surgery, with 5% glucose initially, followed by elemental diets. Postoperative morbidity that necessitated long-term ICU stay is listed in Table 3.
Statistical analyses were conducted with SAS version 5.0 software (SAS Institute, Inc., Cary, NC, USA). The values were expressed as mean ± standard error of the mean. The chi-square test and Student’s t test were used for statistical analysis, and a p-value of less than 0.05 was considered to be significant.
|
RESULTS
|
|---|
All patients in the nonsurvivors group died of multiorgan failure with or without systemic infection. At the start of ICU management, there were no significant differences in hematological and biochemical parameters between the two groups. However, levels of glutamic oxaloacetic transaminase and glutamic pyruvic transaminase were slightly higher in nonsurvivors than in survivors (Table 2
). Gastrointestinal complications were significantly more frequent ( p < 0.01) among the nonsurvivors than the survivors. There were no significant differences between the two groups in other causes of morbidity. However, the percentages of patients with cardiac failure, infection, and renal failure were slightly higher in the nonsurvivors than in the survivors (Table 3). The ICU stay of the survivors and nonsurvivors was 27 ± 2 days and 36 ± 4 days, respectively ( p > 0.05). The period of respiratory support was significantly shorter in the survivors than in the nonsurvivors (18 ± 2 versus 32 ± 4 days; p < 0.01). Twenty-five (45%) of the 55 patients tolerated enteral feeding with elemental diets on postoperative day 14. The total calorie intake aimed for was 30 and 70 calories per kg per day in adults and infants, respectively. Significantly more patients on enteral feeding on day 14 survived compared to those without enteral feeding (22/25 versus 13/30; 88% versus 43%; p < 0.01). The mean serum levels of cholinesterase and total cholesterol on postoperative day 7 and especially on day 14 were higher in survivors than nonsurvivors (Table 4), but there were no significant differences between the two groups in terms of the other biochemical parameters.
|
DISCUSSION
|
|---|
Prolonged postoperative ICU stay is generally associated with underlying morbidity. In this study, cardiac failure, infection, renal failure, liver dysfunction and gastrointestinal complications were the major causes of morbidity. Among these incidences of morbidity, gastrointestinal complications were significantly associated with postoperative mortality. Prolonged bypass time, intraoperative hypotension, and postoperative low cardiac output requiring intraaortic balloon pump support have been reported to lead to gastrointestinal complications, which relate to splanchnic hypoperfusion secondary to ischemia of the visceral organs.4–7 In our previous clinical study, splanchnic perfusion recovered within 24 hours postoperatively in patients with normal cardiac output, however, it remained low in those with low cardiac output syndrome.8 Berger and colleagues9 reported that intestinal absorption was not suppressed but only delayed due to decreased pyloric motility during low cardiac output, and early enteral nutrition was tolerated. In this study, 88% of patients on enteral feeding survived. The initiation of enteral feeding may play an important role not only for nutrition but also in the recovery of the enterohepatic circulation, especially in patients in an immunosuppressive state following cardiac surgery.10 The levels of glutamic oxaloacetic transaminase and glutamic pyruvic transaminase were slightly higher in the nonsurvivors than in the survivors just after surgery, which might lead to a paralytic condition. The percentages of patients with cardiac failure and renal failure were slightly higher among nonsurvivors, nevertheless, there were no significant differences, probably due to the small number of cases. Thus, recovery from underlying cardiac failure was also indispensable for the initiation of enteral nutrition. The prevention and treatment of postoperative gastrointestinal complications seems to be critical for patients with prolonged ICU stay.
Serum albumin concentration, body mass index, and some risk stratification scoring systems have been reported as preoperative predictors of postoperative outcome in cardiac surgical patients.11–13 Postoperative predictors of outcome in patients with prolonged ICU stay following cardiac surgery have not yet been defined. Thompson and colleagues14 described the Edinburgh Cardiac Surgery Score, which indicated that extent of inotropic support, duration of mechanical ventilation, and units of platelets were valuable predictors of postoperative outcome. In our study, serum cholinesterase and total cholesterol concentrations significantly decreased after day 7 in the nonsurvivors, leading us to consider that these might be factors that could strengthen the clinical decision-making process. A low value of serum cholinesterase has been reported as a preoperative predictor of poor outcome in cardiac surgical patients with severe liver dysfunction, however, it has not been used for postoperative evaluation.15 We believe that the decreases of serum cholinesterase and total cholesterol reveal the onset of secondary postoperative cachexia associated with a decline of liver synthetic function. These two values were maintained in the survivors in this study. It was concluded that the introduction of enteral feeding, besides management of underlining cardiac failure, is critical for improved splanchnic perfusion and systemic condition following cardiac surgery, resulting in good operative outcomes.
|
REFERENCE
|
|---|
- Myles PS, Buckland MR, Weeks AM, Bujor MA, McRae R, Langley M, et al. Hemodynamic effects, myocardial ischemia, and timing of tracheal extubation with propofol-based anesthesia for cardiac surgery. Anesth Analg
1997;84:12–9.[Abstract]
- Foster GH, Conway WA, Pamulkov N, Lester JL, Magilligan DJ Jr. Early extubation after coronary artery bypass: brief report. Crit Care Med
1984;12:994–6.[Medline]
- Ishikawa S, Ohtaki A, Takahashi T, Koyano T, Hasegawa Y, Ohki S, et al. Availability of nasal mask BiPAP systems for treatment of respiratory failure after cardiac surgery. J Cardiovasc Surg (Torino)
1998;38:611–3.
- Ohri SK, Desai JB, Gaer JA. Intraabdominal complications after cardiopulmonary bypass. Ann Thorac Surg
1991;52:826–31.[Abstract]
- Aranha GV, Pickleman J, Pifarre R, Scanlon PJ, Gunnar RM. The reasons for gastrointestinal consultation after cardiac surgery. Am Surg
1984;50:301–4.[Medline]
- Welling RE, Rath R, Albers JE, Glaser RS. Gastrointestinal complications after cardiac Surgery. Arch Surg
1986;121:1178–80.[Abstract/Free Full Text]
- Christenson JT, Schmuziger M, Maurice J, Simonet F, Velebit V. Postoperative visceral hypotension the common cause for gastrointestinal complications after cardiac surgery. Thorac Cardiovasc Surg
1994;42:152–7.[Medline]
- Takahashi T, Kunimoto F, Ichikawa H, Ishikawa S, Sato Y, Hasegawa Y, et al. Gastric intramucosal pH and hepatic venous oxymetry in patients with valve replacement. Cardiovasc Surg
1996;4:308–10.[Medline]
- Berger MM, Berger-Gryllaki M, Wiesel PH, Revelly JP, Hurni M, Cayeux C, et al. Intestinal absorption in patients after cardiac surgery. Crit Care Med
2000;28:2217–23.[Medline]
- Navarro M, Lozano R, Larrad L, Roman A, Suarez J, Armijo J. Variation in helper cell/T cytotoxic-suppressor cell index during cardiac operations. J Thorac Cardiovasc Surg
1988;96:962–6.[Abstract]
- Engelman DT, Adams DH, Byrne JG, Aranki SF, Collins JJ, Couper GS, et al. Impact of body mass index and albumin on morbidity and mortality after cardiac surgery. J Thorac Cardiovasc Surg
1999;118:866–73.[Abstract/Free Full Text]
- Rich MW, Keller AJ, Schechtman KB, Marshall WG, Kouchoukos NT. Increased complications and prolonged hospital stay in elderly cardiac surgical patients with low serum albumin. Am J Cardiol
1989;63:714–8.[Medline]
- Geissler HJ, Holzl P, Marohl S, Kuhn-Regnier F, Mehlhorn U, Sudkamp M, et al. Risk stratification in heart surgery: comparison of six score systems. Eur J Cardio-thorac Surg
2000;17:400–6.[Abstract/Free Full Text]
- Thompson MJ, Elton RA, Sturgeon KR, Manclark SL, Fraser AK, Walker WS, et al. The Edinburgh Cardiac Surgery Score survival prediction in the long-stay ICU cardiac surgical patient. Eur J Cardio-thorac Surg
1995;9:419–25.[Abstract]
- Hirata N, Sawa Y, Matsuda H. Predictive value of preoperative serum cholinesterase concentration in patients with liver dysfunction undergoing cardiac surgery. J Card Surg
1999;14:172–7.[Medline]
TOP
ABSTRACT
INTRODUCTION
