Randomized clinical trial
Randomized clinical trial on the effect of coffee on
postoperative ileus following elective colectomy
S. A. Müller1 , N. N. Rahbari1 , F. Schneider1 , R. Warschkow2 , T. Simon1 , M. von Frankenberg1 ,
U. Bork1 , J. Weitz1 , B. M. Schmied1 and M. W. Büchler1
1
Department of General, Visceral and Transplant Surgery, University Hospital Heidelberg, and 2 Institute of Medical Biometry and Informatics,
University of Heidelberg, Heidelberg, Germany
Correspondence to: Dr S. A. Müller, Department of Surgery, Kantonsspital St Gallen, 9007 St Gallen, Switzerland (e-mail: [email protected])
Background: Postoperative ileus is a common problem after abdominal surgery. It was postulated that
coffee intake would decrease postoperative ileus after colectomy.
Methods: This was a multicentre parallel open-label randomized trial. Patients with malignant or benign
disease undergoing elective open or laparoscopic colectomy were assigned randomly before surgery to
receive either coffee or water after the procedure (100 ml three times daily). The primary endpoint was
time to first bowel movement; secondary endpoints were time to first flatus, time to tolerance of solid
food, length of hospital stay and perioperative morbidity.
Results: A total of 80 patients were randomized, 40 to each group. One patient in the water arm was
excluded owing to a change in surgical procedure. Patient characteristics were similar in both groups.
In intention-to-treat analysis, the time to the first bowel movement was significantly shorter in the
coffee arm than in the water arm (mean(s.d.) 60·4(21·3) versus 74·0(21·6) h; P = 0·006). The time to
tolerance of solid food (49·2(21·3) versus 55·8(30·0) h; P = 0·276) and time to first flatus (40·6(16·1)
versus 46·4(20·1) h; P = 0·214) showed a similar trend, but the differences were not significant. Length of
hospital stay (10·8(4·4) versus 11·3(4·5) days; P = 0·497) and morbidity (8 of 40 versus 10 of 39 patients;
P = 0·550) were comparable in the two groups.
Conclusion: Coffee consumption after colectomy was safe and was associated with a reduced time to
first bowel action. Registration number: NCT01079442 (http://www.clinicaltrials.gov).
Paper accepted 12 June 2012
Published online in Wiley Online Library (www.bjs.co.uk). DOI: 10.1002/bjs.8885
Introduction
Postoperative ileus is common after abdominal surgery,
especially after procedures involving the colon1,2 . Symptoms commonly associated with ileus include abdominal
distension, pain, nausea, vomiting and intestinal cramps3 .
Postoperative ileus contributes to prolonged hospital stay
and has a major economic impact on healthcare services4,5 .
It has been estimated to account for additional hospital
costs of US $750 million per year in the USA5,6 . Ileus
delays oral food intake and may require treatment, including nasogastric tube decompression, electrolyte replacement and analgesia.
Owing to the significant implications of ileus after
colectomy and the lack of effective therapies, surgeons
have devised various preventive strategies7 . Multimodal
 2012 British Journal of Surgery Society Ltd
Published by John Wiley & Sons Ltd
approaches used to treat ileus after colorectal surgery
include the use of laparoscopy to minimize surgical trauma,
an early return to solid food intake and mobilization,
avoidance of nasogastric tubes, use of thoracic epidural
analgesia and restrictive fluid management8 . The aim of
these so-called ‘fast-track programmes’ has been to provide
pain- and stress-free operations with lower rates of organ
dysfunction, thereby reducing morbidity and enhancing
recovery9 .
The intake of coffee might offer a simple approach
to alleviating or preventing ileus after elective colectomy.
Coffee is a popular beverage, and its effects on general wellbeing, the central nervous system and the cardiovascular
system are well known10 . Although coffee may stimulate
bowel function in certain healthy volunteers11 , there
is limited scientific evidence regarding its effects on
British Journal of Surgery 2012; 99: 1530–1538
Effect of coffee on postoperative ileus following elective colectomy
gastrointestinal function. In particular, there has been no
prospective evaluation of its impact on intestinal function
after elective colectomy. The aim of this randomized
clinical trial was to assess whether coffee consumption
accelerates the recovery of bowel function after elective
colectomy.
Methods
This multicentre open-label randomized clinical trial was
undertaken at one university hospital (University of Heidelberg, Germany, enrolment from March 2010) and two
affiliated teaching hospitals (Krankenhaus Salem, Heidelberg, Germany, enrolment from October 2010; GRN
Krankenhaus Sinsheim, Sinsheim, Germany, enrolment
from May 2010). The departments of surgery of all three
centres are headed by M.W.B., and patients are distributed
to the centres according to operative complexity. Adult
patients (aged at least 18 years) scheduled for elective open
or laparoscopic colonic resection for malignant or benign
diseases were eligible for inclusion in the study. Written informed consent was obtained on the day before
surgery. Preoperative data, including coffee drinking and
smoking habits, were obtained from a standardized, selfadministered patient questionnaire. Patients were excluded
if rectal resection was intended, a stoma was required or
multivisceral resection was planned. Further exclusion criteria were known hypersensitivity or distaste for coffee,
expected lack of compliance, and an impaired mental state.
Randomized patients were excluded if the intended colonic
surgery was not performed. The independent ethics committee of the University of Heidelberg approved the study.
Randomization and masking
A randomization list for 80 patients with an allocation
ratio of 1 : 1 was generated with SAS version 9.1
software (SAS Institute, Cary, North Carolina, USA),
without stratification by centre. Allocation assignments
were deposited in consecutively numbered, opaque, sealed
envelopes and stored in the study office. For allocation
the study manager was called the day before surgery
after informed consent had been obtained. Patients were
informed about the treatment assignment before surgery.
Neither the physician nor the patient was blinded to the
treatment assignment.
Objectives and endpoints
The primary objective of this trial was to investigate
whether postoperative coffee intake reduces the duration of
 2012 British Journal of Surgery Society Ltd
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1531
postoperative ileus after elective colectomy. The primary
endpoint was time to the first postoperative bowel
movement (time from the end of surgery until the first
passage of stool recorded by nursing staff) as a surrogate
endpoint for the duration of ileus. Secondary endpoints
were time to tolerance of solid food (no vomiting), time
to first flatus, need for additional laxatives, safety, and
length of hospital stay (interval from day of operation until
day of discharge). The time to first postoperative bowel
movement, tolerance of solid food and first flatus was
recorded in hours after the end of the operation. Safety
was measured by the rate and degree of postoperative
complications12 . Anastomotic leakage was defined as the
communication between intraluminal and extraluminal
compartments owing to a defect in the intestinal wall
at the site of the anastomosis, which was confirmed by
imaging or relaparotomy13 . Perioperative mortality was
defined as any death within 30 days after surgery. All study
endpoints were predefined in the study protocol.
Surgical technique and perioperative care
After enrolment, the same evidence-based protocol of
perioperative management was applied to all patients,
following the principles of fast-track surgery7 . In brief,
patients did not undergo mechanical bowel preparation
and no oral antibiotic preparation was used. Patients
scheduled for left hemicolectomy or rectosigmoid resection
received one enema before surgery. All patients received
a single dose of antibiotic prophylaxis consisting of
4 g mezlocillin and 0·5 g metronidazole at the time of
anaesthesia induction. Low molecular weight heparin
was administered and venous compression stockings were
used, starting the night before surgery. Unless the
patient refused, participants in both study arms received
a thoracic epidural catheter (TEC) that was removed
on day 3 after surgery or thereafter. Epidural catheters
were filled with 0·2 per cent ropivacaine hydrochloride
plus 0·25–0·5 µg/ml sufentanil, administered at a rate
of 8–10 ml/h, with the rate reduced as quickly as
possible. Peripheral non-steroidal analgesics (metamizole
or paracetamol) formed the basis of the analgesic
therapy. After the TEC had been removed, non-steroidal
analgesics were combined with opioids (2 mg oxycodon
intravenously or 10 mg Targin (Mundipharma Medical,
Hamilton, Bermuda) intramuscularly for breakthrough
pain if necessary. Postoperative pain was assessed at least
three times daily by means of a visual analogue scale and
the pain regimen was adapted accordingly.
All operations were performed by, or under the close
supervision of, a consultant surgeon, either laparoscopically
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S. A. Müller, N. N. Rahbari, F. Schneider, R. Warschkow, T. Simon, M. von Frankenberg et al.
or by an open approach via a midline laparotomy. A doublelayer, handsewn anastomosis was performed in open
surgery. During hand-assisted laparoscopic procedures, a
circular stapler was used to achieve end-to-end or endto-side colorectal anastomosis. Nasogastric tubes were
removed during extubation.
The postoperative feeding regimen was standardized.
In summary, water was offered 6 h after surgery, liquid
food from the first day after surgery, and solid food
from the second day. The postoperative feeding regimen
was determined by the patient’s ability and willingness
to consume food and was not dependent on intestinal
function, such as passage of flatus or bowel movements.
Except for oral magnesium (1200 mg/day) and macrogol
(polyethylene glycol; 3 bags, equivalent to 39·3 g/day)
according to a fixed regimen in both study arms, no further
laxative/prokinetic therapy was allowed. In the event
of postoperative nausea and vomiting, patients received
parenteral fluids and dimenhydrinate (62 mg in 10 ml
injection solution) or granisetron (3 mg in 50 ml injection
solution). The postoperative mobilization schedule was
standardized according to in-house protocols and was the
same for both study groups. Criteria for hospital discharge
included stable vital signs with no febrile morbidity for at
least 24 h, passage of stool, toleration of a regular diet, and
the absence of other complications.
Trial interventions
Patients in the treatment (coffee) arm had to drink three
cups of coffee daily (100 ml at 08.00 12.00 and 16.00 hours),
beginning on the morning after surgery. In the control arm
coffee was replaced by warm water. Patients randomized
to water were not allowed coffee at all until the first bowel
movement had occurred. The beverages were served at
50–60° C, and the patients were asked to drink the entire
volume within 10 min under the supervision of a nurse. No
additives (such as milk or sugar) were allowed. All patients
were instructed not to consume black tea or additional
coffee. However, they were free to drink any amount
of still mineral water. No further restrictions on food
consumption (for example chocolate) or smoking were
imposed. Coffee was prepared with a conventional coffee
machine using the same brand and type of coffee capsules
(Lavazza Blue Espresso Dolce 100 per cent Arabica coffee,
8 g coffee per capsule; Lavazza Germany, Frankfurt,
Germany).
Statistical analysis
For the power calculation, superiority of the primary
endpoint, time to first bowel movement, in the treatment
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arm was assumed (H1 hypothesis). Previous studies on
postoperative ileus after colectomy showed a mean time
to the first bowel movement of 89·4–93·6 h for control
patients, with a standard deviation of 24–36 h14,15 . To
detect a clinically relevant absolute difference of 24 h
in time to the first bowel movement with a two-sided
significance level of 0·05 and a power of 80 per cent, it
was calculated that 36 patients per study arm would be
required assuming a standard deviation of 36 h. With
an estimated dropout rate of 10 per cent (postoperative
refusal or protocol violations), a total of 80 patients were
needed for the study. No interim analysis was planned or
performed, and no early stopping rules were implemented.
Continuous data are presented as mean(s.d.). Time to
first bowel movement, time to tolerance of solid food
and time to first flatus were assessed by means of t
test and ANOVA, as appropriate. Other continuous data
were compared using the Mann–Whitney U test, and
categorical data with the χ2 test. Ninety-five per cent
confidence intervals (c.i.) of proportions were calculated
by the Wilson score method. All endpoints were analysed
on an intention-to-treat (ITT) basis. For confirmation,
per-protocol (PP) analysis was also carried out. In an
ancillary analysis, the primary endpoint (mean ranks)
was assessed by multivariable regression analysis with
backward variable selection. P values were estimated with
likelihood ratio tests. Two-sided P < 0·050 was considered
statistically significant. Statistical analyses were performed
using SPSS version 17.0 (SPSS, Chicago, Illinois, USA)
and the R Project for Statistical Computing version 2.12.2
(http://www.r-project.org).
Results
Patients were recruited between March 2010 and March
2011. Of 103 eligible patients, 80 were randomized, 40
to each study arm (University Hospital Heidelberg 45,
Salem 17, Sinsheim 18). Five patients randomized to
receive coffee did not receive the allocated intervention:
two were unable to drink coffee in the days after surgery
and two could drink less than the scheduled amount (all
four patients usually drink coffee). One patient received
water owing to an allocation error. The mean amount of
coffee consumed until the first bowel movement in the
coffee group was 497(287) ml (excluding the five patients
who did not receive the scheduled amount). One patient
in the control arm underwent palliative enteric bypass
surgery and was excluded from the study. A further four
patients in this group did not comply with the protocol
and drank 30–300 ml coffee. For ITT analysis patients
were grouped according to the randomization, apart from
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British Journal of Surgery 2012; 99: 1530–1538
Effect of coffee on postoperative ileus following elective colectomy
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Assessed for eligibility n = 103
Enrolment
Excluded n = 23
Did not meet inclusion criteria
n = 16
Declined to participate n = 5
Other reason n = 2
Fig. 1
Allocated to coffee arm n = 40
ITT analysis
Allocated to control (water) arm n = 40
Analysed n = 39
Excluded from analysis n = 1
Intraoperative change to bypass
surgery n = 1
Analysed n = 40
Excluded from analysis n = 0
PP analysis
Allocation
Randomized n = 80
Analysed n = 36
Excluded from analysis n = 5
Intraoperative change to bypass n = 1
Non-compliance (off-protocol coffee
consumption) n = 4
Included from coffee arm n = 1
Allocation error n = 1
Analysed n = 35
Excluded from analysis n = 5
Completely refused coffee n = 2
Partially refused coffee n = 2
Allocation error n = 1
CONSORT diagram for the trial. ITT, intention-to-treat; PP, per-protocol
Table 1
Patient characteristics
Age (years)*
Sex ratio (M : F)
ASA grade
I
II
III
Type of colonic disease
Malignant
Benign
Diagnosis
Colonic cancer
Diverticular disease
Inflammatory bowel disease
Other
Coffee drinker before surgery
Preop. coffee intake (ml/day)*†
Smoker
Co-morbidities
Cardiovascular
Pulmonary
Renal
Diabetes mellitus
Table 2
Total
(n = 79)
Water
(n = 39)
Coffee
(n = 40)
61(14)
44 : 35
59(15)
19 : 20
62(12)
25 : 15
8 (10)
48 (61)
23 (29)
3 (8)
24 (62)
12 (31)
5 (13)
24 (60)
11 (28)
45 (57)
34 (43)
22 (56)
17 (44)
23 (58)
17 (43)
44 (56)
22 (28)
10 (13)
3 (4)
69 (87)
375(354)
14 (18)
20 (51)
11 (28)
6 (15)
2 (5)
34 (87)
315(220)
9 (23)
24 (60)
11 (28)
4 (10)
1 (3)
35 (88)
433(443)
5 (13)
36 (46)
10 (13)
5 (6)
14 (18)
18 (46)
4 (10)
1 (3)
5 (13)
18 (45)
6 (15)
4 (10)
9 (23)
Values in parentheses are percentages unless indicated otherwise; *values
are mean(s.d.). ASA, American Society of Anesthesiologists. †Only in
coffee drinkers before surgery, according to patient questionnaire.
 2012 British Journal of Surgery Society Ltd
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Surgical procedures and perioperative results
Surgical procedure
Ileocaecal resection
Right hemicolectomy
Left hemicolectomy
Sigmoid/rectosigmoid
resection
Surgical approach
Open
Laparoscopic
Duration of operation (min)*
Epidural analgesia
Blood loss (ml)*
Patient received PRBC
ICU admission
Total
(n = 79)
Water
(n = 39)
Coffee
(n = 40)
10 (13)
26 (33)
9 (11)
34 (43)
6 (15)
15 (38)
5 (13)
13 (33)
4 (10)
11 (28)
4 (10)
21 (53)
48 (61)
31 (39)
179(56)
68 (86)
176(162)
10 (13)
15 (19)
24 (62)
15 (38)
183(57)
34 (87)
202(211)
7 (18)
8 (21)
24 (60)
16 (40)
173(56)
34 (85)
150(87)
3 (8)
7 (18)
P†
0·392
0·889
0·410‡
0·780
0·487‡
0·163
0·733
Values in parentheses are percentages unless indicated otherwise; *values
are mean(s.d.). PRBC, packed red blood cells; ICU, intensive care unit.
†χ2 test, except ‡Mann–Whitney U test.
the excluded patient for whom no primary endpoint was
available. For the PP analysis, all patients who followed the
protocol were considered (Fig. 1). Patient characteristics
(Table 1), surgical procedures, duration of operation and
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S. A. Müller, N. N. Rahbari, F. Schneider, R. Warschkow, T. Simon, M. von Frankenberg et al.
perioperative results did not differ significantly between
the two study groups in ITT analysis (Table 2).
Reinsertion of a nasogastric tube was required in 16
patients (20 per cent). The time to first bowel movement
was significantly shorter in the coffee arm (ITT: 60·4(21·3)
versus 74·0(21·6) h, P = 0·006; PP: 62·1(21·5) versus
73·7(22·0) h, P = 0·028) (Tables 3 and 4). The absolute
difference was 13·6 (95 per cent c.i. 4·0 to 23·2) h in
ITT analysis and 11·6 (1·3 to 21·9) h in PP analysis.
Univariable analysis demonstrated that time to first bowel
movement was also significantly associated with the
American Society of Anesthesiologists grade (Table 5). In
multivariable regression analysis, coffee consumption and
ASA grade were the only significant co-variables for the
time to first bowel movement (Table 5). Sex and type of
operation had some influence, but were not statistically
significant. Anastomotic leakage had no effect.
Table 3
As anastomotic leakage could hypothetically prolong
the time to first bowel movement and more patients in the
water group experienced an anastomotic leak (Table 3), a
subgroup analysis was carried out on patients without a leak.
Time to bowel movement remained significantly shorter
in the coffee arm (ITT: 60·4 versus 74·0 h; P = 0·004).
The secondary endpoints – time to tolerance of solid
food, time to first flatus (reported by 61 patients), need
for laxatives and length of hospital stay – were reduced in
the coffee arm, but there were no significant differences
except for time to tolerance of solid food in PP analysis
(P = 0·038) (Tables 3 and 4).
No patient died within 30 days of operation and the
overall morbidity rate was 22 per cent, with no significant
difference between the two groups. The rate of anastomotic
leak (12·8 (95 per cent c.i. 5·6 to 26·7) versus 2·5 (0·4 to
12·9) per cent) and reoperations was higher in the control
Outcome data: intention-to-treat analysis
Time to first bowel movement (h)
Time to tolerance of solid food (h) (n = 76)
Time to first flatus (h) (n = 61)
Use of any laxative*
Enema
Prokinetics
Enteral laxative
Length of hospital stay (days)
Reinsertion of nasogastric tube*
Abdominal reoperation*
Total morbidity*
Grade of complications12 *
I
II
IIIB
IVA
Anastomotic leakage*
Grade of anastomotic leakage13 *
A
B
C
Total (n = 79)
Water (n = 39)
Coffee (n = 40)
Absolute difference†
P‡
67·2(22·4)
52·5(24·9)
43·3(18·2)
34 (43)
15 (19)
5 (6)
19 (24)
11·1(4·4)
16 (20)
5 (6)
18 (23)
74·0(21·6)
55·8(30·0)
46·4(20·1)
21 (54)
10 (26)
3 (8)
11 (28)
11·3(4·5)
10 (26)
4 (10)
10 (26)
60·4(21·3)
49·2(21·3)
40·6(16·1)
13 (33)
5 (13)
2 (5)
8 (20)
10·8(4·4)
6 (15)
1 (3)
8 (20)
13·6 (4·0, 23·2)
6·6 (−5·4, 18·4)
5·8 (−3·5, 15·2)
0·006§
0·276§
0·214§
0·055
0·137
0·623
0·394
0·497¶
0·239
0·157
0·550
0·344¶
8 (10)
4 (5)
5 (6)
1 (1)
6 (8)
3 (8)
3 (8)
4 (10)
0 (0)
5 (13)
5 (13)
1 (3)
1 (3)
1 (3)
1 (3)
2 (3)
1 (1)
3 (4)
1 (3)
1 (3)
3 (8)
1 (3)
0 (0)
0 (0)
0·5 (−1·5, 2·6)
0·083
0·206¶
Values are mean(s.d.) unless indicated otherwise; values in parentheses are *percentages and †95 per cent confidence intervals. ‡χ2 test, except §t test and
¶Mann–Whitney U test.
Table 4
Outcome data: per-protocol analysis
Time to first bowel movement (h)
Time to tolerance of solid food (h) (n = 68)
Time to first flatus (h) (n = 55)
Use of any laxative*
Length of hospital stay (days)
Total (n = 71)
Water (n = 36)
Coffee (n = 35)
Absolute difference†
P‡
68·0(22·4)
51·4(24·5)
43·8(18·4)
30 (42)
10·8(4·0)
73·7(22·0)
57·3(29·3)
47·1(20·5)
19 (53)
11·6(4·6)
62·1(21·5)
45·1(16·4)
40·6(15·9)
11 (31)
10·0(3·2)
11·6 (1·3, 21·9)
12·3 (0·7, 23·8)
6·5 (−3·4, 16·4)
0·028
0·038
0·191
0·069§
0·129¶
1·6 (−0·3, 3·5)
Values are mean(s.d.) unless indicated otherwise; values in parentheses are *percentages and †95 per cent confidence intervals. ‡t test, except §χ2 test and
¶Mann–Whitney U test.
 2012 British Journal of Surgery Society Ltd
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British Journal of Surgery 2012; 99: 1530–1538
Effect of coffee on postoperative ileus following elective colectomy
Table 5
1535
Analysis of co-variables for the primary outcome
Univariable analysis
Time to first bowel movement (h)*
Treatment arm
Water
Coffee
Sex
M
F
Age (years)
< 65
≥ 65
ASA grade
I
II
III
Smoker
No
Yes
Coffee drinker
No
Yes
Type of colonic disease
Malignant
Benign
Epidural analgesia
No
Yes
Surgical procedure
Ileocaecal resection
Right hemicolectomy
Left hemicolectomy
Sigmoid/rectosigmoid resection
Surgical approach
Open
Laparoscopic
Anastomotic leakage
No
Yes
Full regression model¶
P‡
β-coefficient†
P**
0·006
74·0(21·6)
60·4(21·3)
0·674
0·065
Reference
−8·7 (−18·4, 1·1)
0·474
Reference
4·1 (−8·6, 16·8)
0·020§
46·6(16·4)
68·9(21·3)
70·7(23·4)
0·009
Reference
25·0 (7·0, 42·9)
27·2 (6·0, 48·4)
0·702
67·6(23·3)
65·1(18·4)
0·004
Reference
25·0 (8·8, 41·1)
29·2 (10·7, 47·7)
0·747
Reference
−2·1 (−16·5, 12·3)
0·559
71·1(20·2)
66·6(22·8)
0·779
Reference
−2·0 (−17·6, 13·6)
0·701
66·3(21·4)
68·3(23·9)
0·531
Reference
3·5 (−8·8, 15·8)
0·750
65·1(25·3)
67·5(22·1)
0·838
Reference
−2·2 (−18·0, 13·0)
0·605§
59·9(20·3)
65·6(18·4)
72·1(25·2)
69·2(25·2)
0·131
Reference
4·4 (−16·7, 25·5)
12·8 (−9·6, 35·2)
15·0 (−2·2, 32·2)
0·842
66·8(20·2)
67·8(26·0)
0·074
Reference
2·2 (−13·7, 18·1)
12·0 (−7·0, 31·0)
14·9 (−0·1, 29·9)
0·769
Reference
1·2 (−11·9, 14·3)
0·156
66·1(21·2)
79·7(33·5)
< 0·001
0·068
0·163
P**
Reference
−16·0 (−25·5, −6·4)
Reference
−9·1 (−20·0, 1·9)
63·9(20·1)
71·0(24·6)
β-coefficient†
0·002
Reference
−15·2 (−25·7, −4·7)
68·1(21·4)
66·0(23·9)
Regression model#
0·651
Reference
4·2 (−16·3, 24·6)
*Values are mean(s.d.); †values in parentheses are 95 per cent confidence intervals. ASA, American Society of Anesthesiologists. ‡t test, except §ANOVA.
¶Full regression model; #backward variable selection regression model; **likelihood ratio test.
arm than in the coffee arm, but the differences were not
significant.
Discussion
In this randomized trial the time to first bowel movement
was significantly shorter after regular coffee consumption
during the postoperative period after elective colectomy.
Although about 10 per cent of the patients did not want
to drink strong coffee at this time, coffee consumption
was well accepted by the patients and no coffee-related
complications were noted.
Postoperative ileus is defined as the delayed return
of physiological coordinated gastrointestinal motility
and commonly occurs after intra-abdominal surgery,
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but also after retroperitoneal or even extra-abdominal
surgery16,17 . It is usually self-resolving. The inhibition
of small bowel motility is transient, and the stomach
recovers within 24–38 h, whereas colonic function takes
48–72 h to recover6,18,19 . The mechanisms involved
in postoperative ileus include inhibitory sympathetic
input, release of hormones, neurotransmitters and other
mediators, inflammatory reactions, the effects of analgesics
and the effects of surgical manipulation20 . A timely
return of bowel mobility is highly relevant clinically
as a delay causes discomfort to the patient, prolongs
hospital stay and increases healthcare expenditure5,21 .
Sarawate and colleagues22 reported that hospital stay was
on average 3 days longer for patients with postoperative
ileus than for those without, leading to increased costs
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S. A. Müller, N. N. Rahbari, F. Schneider, R. Warschkow, T. Simon, M. von Frankenberg et al.
of US $4000–9000 per hospital stay for intra-abdominal
operations22 .
Multimodal approaches have been developed to reduce
the incidence of postoperative ileus and the length
of hospital stay, including the use of drugs, epidural
anaesthesia, surgical techniques and early feeding23 .
Laparoscopic colonic surgery has been studied widely
in recent years and has been shown consistently to
improve many short-term outcomes compared with open
surgery24,25 . Carli and co-workers26 reported that thoracic
epidural analgesia has distinct advantages over patientcontrolled morphine analgesia in providing superior
quality of analgesia and shortening the duration of
postoperative ileus26 . On the other hand, a recently
published multicentre trial showed that epidural analgesia
and laparoscopy had no influence on the rate of ileus after
sigmoid resection for diverticular disease27 . These factors
were also found to have no effect on time to first bowel
movement in the present study, even though all types of
elective colonic resection were included, for malignant as
well as benign diseases.
Another approach is medical treatment with µ-receptor
antagonists (such as alvimopan), particularly to target
opioid-induced postoperative ileus28 . In a study by Bell
and colleagues29 , use of alvimopan was associated with a
significantly shorter mean time to gastrointestinal recovery
(18·8 (95 per cent c.i. 13·2 to 24·4) h) and decrease of 1
full day in hospital stay compared with placebo, saving
around US $900 per patient. The mean costs of coffee
in the present study (on average five cups to first bowel
movement) were US $2·80 for each patient. Compared with
the costs of alvimopan (mean 8·9 12-mg doses, US $558
per patient)29 , drinking coffee is a considerably cheaper
treatment with a similar effect.
New medications for the treatment of postoperative
ileus, such as ghrelin receptor agonists, are currently being
tested in clinical studies. Another way of stimulating bowel
function after colonic resection is sham feeding in the
form of gum chewing. Asao and co-workers2 reported
an earlier return of bowel function and a trend towards
earlier hospital discharge in patients who chewed gum
after laparoscopic colectomy. Chewing gum is postulated
to activate the cephalic vagal reflex, which is usually
enhanced by food, and to increase the production of
gastrointestinal hormones that are associated with bowel
motility2 . However, none of these treatments has gained
general acceptance in clinical practice.
Although there is a vast literature on the effects of
coffee, little is known about its effect on the bowel. In a
study in which healthy volunteers reported their desire to
defaecate after consuming coffee, the rectosigmoidal motor
responses to coffee consumption were measured using
multiport manometry11 . The authors found an increase in
colonic motor activity 4 min after the ingestion of regular
as well as decaffeinated coffee in the responders, but not
among non-responders. None of the volunteers showed a
response after the ingestion of water. In an investigation
of the effects of 240 ml regular coffee, decaffeinated
coffee, water and a 1000-kcal (approximately 4000 kJ)
meal on colonic motility, Rao and colleagues30 performed
ambulatory manometry with a catheter positioned from the
rectum up to the mid-transverse colon3 . Regular coffee,
decaffeinated coffee and a meal induced more colonic
activity and more propagated contractions than water.
It was concluded that caffeinated coffee stimulates colonic
motor activity to a magnitude comparable to that of a highcalorie meal. These previous studies examined the effect of
coffee on colonic motility in healthy volunteers, whereas
the present trial demonstrated that coffee can stimulate
bowel activity in patients after elective colectomy. Thus,
coffee consumption offers a simple strategy to shorten the
time to first bowel movement.
Neither this nor previous studies can explain the
mechanisms by which coffee stimulates intestinal motility.
Although the most obvious stimulatory agent is caffeine,
in a previous study decaffeinated coffee had an effect on
bowel peristalsis30 . Thus, components other than caffeine
must play a role. Decaffeinated coffee was not used in
the present trial, and it would be interesting to evaluate
its effect in further studies. Alternatively, the effect of
coffee could be physical instead of chemical in nature. For
instance, acidity, osmolality or volume load could stimulate
the gastrointestinal system. However, water did not show
an effect in the present study and the physical properties
of water are very similar to those of coffee, so a physical
effect is less likely.
The study has several limitations. As there were no
previous studies to rely on, the assumptions for the sample
size calculation (difference () 24 h, s.d. 36 h) were rather
arbitrary. The study did not reach its intended goal as the
difference in time to first bowel movement between the
study arms was just under 14 h. However, the standardized
effect size (/s.d.) of 0·64 is very close to the anticipated
value of 0·67. Considering that coffee consumption is part
of the lifestyle of many patients and its side-effects are well
known, the effect of 14 h might still be of clinical interest.
One might question the surrogate endpoint of time to
first bowel movement as an indicator of ileus, but it is
commonly used in similar studies27 . Use of the incidence
of ileus instead would have required a much larger
patient cohort, making this initial trial unfeasible. Another
limitation was the heterogeneity of the patient population,
 2012 British Journal of Surgery Society Ltd
Published by John Wiley & Sons Ltd
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British Journal of Surgery 2012; 99: 1530–1538
Effect of coffee on postoperative ileus following elective colectomy
but this reflects the actual clinical situation. Although
bias resulting from heterogeneity cannot be ruled out
entirely, randomization and the results of the multivariable
and subgroup analyses make this unlikely. The rate of
protocol violation (particularly coffee consumption in the
water arm) was relatively high, but not when the special
circumstance of this study is considered. In contrast to
typical pharmacological studies, all patients had free access
to the test agent (coffee). Although patients were clearly
instructed not to consume coffee if randomized to the
control arm, they did not all comply. Furthermore, blinding
was not feasible even though it would have been desirable
in a randomized trial. Hospital stay in the present study
was relatively long for patients in a fast-track programme.
However, social and insurance issues made it necessary to
prolong hospital stay beyond medical necessity.
Postoperative coffee consumption is a cheap and safe way
to activate bowel motility after elective colonic surgery.
Acknowledgements
S.A.M. and N.N.R. contributed equally to this study. The
authors thank Ulrich Beutner for checking all numbers as
well as critically reviewing the manuscript.
Disclosure: The authors declare no conflict of interest.
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Snapshot Quiz
Snapshot Quiz 12/19
Question: This semi-professional mountain biker injured his left iliac fossa with a handlebar during a jump
stunt. What injury is depicted at operation?
a
b
The answer to the above question is found on page 1583 of this issue of BJS.
Tan MLH, Cheek C, Corder A: Department of General Surgery, The County Hospital, Stonebow Road, Hereford HR1 2BN, UK
(e-mail: [email protected])
Snapshots in Surgery: to view submission guidelines, submit your snapshot and view the archive, please
visit www.bjs.co.uk
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