Nausea and vomiting after fast-track cardiac anaesthesia

A. Kogan*,1, L. A. Eidelman2, E. Raanani1, B. Orlov1, O. Shenkin2 and B. A. Vidne1

1 Department of Cardiothoracic Surgery and 2 Department of Anesthesiology, Rabin Medical Center, Beilinson Campus, Petah-Tiqva 49100, Israel.Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel

Corresponding author. E-mail: akogan@clalit.org.il

Accepted for publication: March 13, 2003


    Abstract
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 Abstract
 Introduction
 Methods
 Results
 Discussion
 References
 
Background. The aim of this study was to determine the prevalence of postoperative nausea and vomiting (PONV) after fast-track cardiac anaesthesia, risk factors for PONV and its influence on the length of stay in the intensive care unit (ICU).

Methods. A prospective study was performed in the cardiothoracic ICU (CTICU) of a university hospital; 1221 consecutive patients undergoing fast-track anaesthesia (FTCA) in cardiac surgery were enrolled in the study. Severity of PONV was assessed immediately after extubation and then every hour until discharge from the CTICU. Metoclopramide 10 mg i.v. was used as a first-line rescue medication and ondansetron 4 mg i.v. as second-line rescue medication for PONV.

Results. Nausea was reported in 240 (19.7%) patients, and vomiting in 53 (4.3%). A total of 269 (22%) patients were treated with metoclopramide and 38 (3.1%) with metoclopramide and ondansetron. The latter was effective in all cases. Risk factors for PONV were age less than 60 yr, female gender and previous history of PONV. Discharge from the CTICU was delayed for a few hours because of PONV in eight patients, all of whom were discharged the same day.

Conclusions. The incidence of PONV is relatively low after FTCA and does not prolong ICU stay. Prophylactic administration of anti-emetic drugs before FTCA is not necessary.

Br J Anaesth 2003; 91: 214–17

Keywords: anaesthesia, cardiac ‘fast-track’; surgery, cardiovascular; vomiting, nausea, postoperative


    Introduction
 Top
 Abstract
 Introduction
 Methods
 Results
 Discussion
 References
 
There has recently been much interest in early extubation following cardiac surgery or fast-track cardiac anaesthesia (FTCA), mainly because it has resulted in a significant reduction in the length of stay in both the intensive care unit (ICU) and the hospital, better resource utilization and lower costs without adversely affecting mortality and morbidity.1 2 Postoperative nausea and vomiting (PONV) are common and distressing symptoms during recovery from anaesthesia and surgery3 and are considered an important cause of postoperative morbidity in non-cardiac surgery.4 While studies of PONV have concentrated on non-cardiac surgical procedures,5 6 limited data suggest that the incidence of PONV in patients undergoing cardiac surgery may be as high as 45–50%.79 We therefore prospectively evaluated the incidence of PONV, risk factors, and its influence on the length of ICU stay after FTCA.


    Methods
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 Abstract
 Introduction
 Methods
 Results
 Discussion
 References
 
After obtaining institutional ethics committee approval and patients’ consent, we prospectively studied all patients undergoing FTCA, which was defined as perioperative anaesthetic management aimed at facilitating tracheal extubation within 8–10 h after surgery and discharge from the ICU on postoperative day 1. Fast-track pathway was defined as a process of care, including a multidisciplinary approach aimed at improving the efficiency of care in cardiac surgical patients.10 Patients who underwent coronary artery bypass grafting, valve-related and combined procedures were included. Patients who had received anti-emetic medication before surgery were excluded. Preoperative, intraoperative and ICU-related data were collected. Preoperative variables included age, sex, obesity, history of diabetes, renal insufficiency and previous PONV and/or motion sickness. All patients were assessed by the modified Parsonnet Score.11 Intraoperative variables included type and urgency of procedure, anaesthesia time and cardiopulmonary bypass (CPB) time. ICU-related data included duration of ventilation, ICU length of stay, need for inotropic support at the time of extubation, total morphine consumption, number of episodes of PONV and need for rescue medication.

Anaesthesia was standardized. Patients were premedicated with midazolam syrup 0.1 mg kg–1. Anaesthesia was induced with fentanyl 10–15 µg kg–1 and midazolam 0.02–0.04 mg kg–1. Pancuronium bromide was administered to facilitate tracheal intubation. A gastric tube was inserted in all patients. The lungs were ventilated with an oxygen/air mixture (FIO2 0.5–0.6) with a tidal volume of 8–10 ml kg–1 to maintain normocapnia. Anaesthesia was maintained with isoflurane, fentanyl and midazolam. Total dose of fentanyl was 20–40 µg kg–1, which was higher than previously reported for fast-track anaesthesia by Cheng and colleagues,12 and of midazolam was 0.15–0.2 mg kg–1. After completion of surgery, patients were transferred to the ICU, where they were treated with warm air heaters to ensure normothermia. Inotropic drugs were continued when needed. Sedation with i.v. midazolam was allowed before extubation. No propofol was used for postoperative seda tion. Analgesia was provided by i.v. morphine injections. Midazolam and morphine were given by intermittent boluses according to patient status. Weaning from the ventilator and extubation were performed according to the protocol proposed by the fast-track cardiac care team.13 Episodes of PONV (nausea, retching and vomiting) were recorded by the nurses every hour, beginning from time of extubation until discharge from the ICU. For the purpose of this study, both actual vomiting and retching were considered as vomiting. I.V. metoclopramide 10 mg was prescribed for all patients as a first-line rescue anti-emetic medication and given as required by the nurse caring for the patient. I.V. ondansetron 4 mg was prescribed by an attending intensivist as a second-line medication in patients who continued to vomit or experienced persistent nausea 30 min after metoclopramide administration. No other anti-emetic medication, including dexamethasone, was used.

Statistical analysis
Numerical data are expressed as mean (SD). Univariate analysis was initially performed to identify risk factors associated with PONV using {chi}2 analyses. P<0.05 was considered statistically significant and odds ratio was calculated. Variables associated with PONV with a P value <0.05 in the univariate analyses were entered into multiple logistic regression analyses to identify independent risk factors. The odds ratio, 95% confidence interval and P values were calculated for each risk factor. P <0.05 was considered statistically significant. Differences in complication rates and lactate concentrations between PONV and non-PONV groups were calculated using Student’s t-test. Differences were considered statistically significant at P <0.05. Statistical analysis was performed using SPSS 8.0 for Windows.


    Results
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 Introduction
 Methods
 Results
 Discussion
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During a 24-month period from March 2000 to March 2002, 2244 open-heart procedures were performed in our department, 1357 (60.5%) of which were defined as FTCA. A total of 136 patients were excluded from the study (134 because of incomplete data and two because they received anti-emetic medication before surgery). Data from 1221 patients were analysed. Pre- and intraoperative data are shown in Table 1. The overall incidence of PONV during the ICU stay after FTCA was 22% (269 patients). Nausea was reported in 240 (19.7%) patients and vomiting in 53 (4.3%). All patients with PONV were treated with i.v. metoclopramide 10 mg and 38 (3.1%) with PONV refractory to metoclopramide were treated with i.v. ondansetron 4 mg. Three patients received ondansetron twice because of severe nausea. No adverse reactions were reported.


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Table 1 Pre- and intraoperative data. AVR, aortic valve replacement; CABG, coronary artery bypass grafting; PONV, postoperative nausea and vomiting
 
ICU-related data are shown in Table 2. Discharge from the ICU was delayed for 5.5 (SD 2.7) h because of severe PONV in only eight patients, all of whom were transferred to the ward the same day. No signs of hypoperfusion were recorded and no differences were found in postoperative lactate concentrations between PONV and non-PONV groups (2.3 (0.9) and 2.4 (1.1) mmol litre–1, respectively). No complications related to PONV were observed. Forty patients (3.3%) required re-admission to the ICU for various complications, mainly respiratory problems and haemodynamic instability. No differences in complication rates between PONV and non-PONV group were found (Table 3). Risk factors associated with PONV by univariate analysis were age less 60 yr, female gender, previous history of PONV, and non-insulin-dependent diabetes (Table 4). From multiple logistic regression analyses (Table 5), risk factors for PONV were age less than 60 yr, female gender and previous history of PONV.


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Table 2 Data relating to the stay in the intensive care unit
 

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Table 3 Complications requiring re-admission to the intensive care unit after fast-track cardiac surgery
 

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Table 4 Risk factors for postoperative nausea and vomiting (PONV) from univariate analyses
 

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Table 5 Risk factors for postoperative nausea and vomiting (PONV) from multiple logistic regression analyses
 

    Discussion
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 Abstract
 Introduction
 Methods
 Results
 Discussion
 References
 
PONV is considered an important and undesirable outcome of anaesthesia and surgery.14 In non-cardiac surgery, PONV may prolong recovery room stay and is one of the most common causes of unplanned hospital admission following ambulatory surgery. While PONV is an unpleasant experience for every patient, vomiting or retching following cardiac surgery may have detrimental effects such as increased myocardial oxygen consumption and postoperative bleeding. Furthermore, troublesome PONV can prolong ICU stay and delay discharge after FTCA, and reduces patient satisfaction and the efficiency of services.

Grebenic and Allman7 and Woodwarg and colleagues8 have previously reported a 46–49% incidence of nausea and 37–42% incidence of vomiting in their patients after cardiac surgery. In our study, the incidence of PONV was considerably lower: 19.7% of patients had nausea and 4.3% had vomiting. This may be related to our practice of using low-to-moderate doses of fentanyl (20–40 µg kg–1) and relatively low doses of morphine (5–15 mg) during the postoperative period. Doses of fentanyl for FTCA used in our study are higher than reported by Cheng and colleagues12 and Silbert and colleagues13 (15 µg kg–1).

Nausea can be associated with a high concentration of cathecholamines.15 However, inotropic support was stopped a few hours before extubation in most cases. Only 108 (8.8%) patients received mild inotropic support at the time of extubation. Gan and colleagues9 consider the use of gut hypoperfusion during CPB as another possible cause of PONV. The duration of CPB in our patients was relatively short: 67.2 (11.3) min. No signs of hypoperfusion were recorded.

Anti-emetics may be administered before, during or after surgery to prevent PONV or may be given after surgery to treat established PONV. The latter approach is a satisfactory option for patients undergoing surgical procedures with a low frequency of PONV, such as FTCA. It is considered reasonable to employ rescue perioperative anti-emetic as needed and to avoid routine prophylactic administration. This strategy avoids side-effects and the cost of unneeded anti-emetic therapy while still providing reasonable control of emesis.16 According to our regimen, metoclopramide 10 mg i.v. is effective in most cases, while ondansetron 4 mg i.v. can be added when complete resolution of PONV is necessary.


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 Discussion
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