Table 1 Summary of extraction articles

2015

USA

Prospective survey

25 intensive care units across 17 institutions

Caffeine intake minimisation was used in 32% of intensive care units as a pharmacological method to reduce delirium

21

2017

Iran

Prospective RCT

80 patients;

40 coffee, 40 placebo

3.5 g coffee given via nasogastric tube in the mechanically ventilated patients increases the spontaneous respiratory rate and tidal volume but does not significantly affect other respiratory indicators.

22

1987

Germany

Prospective observational

12 male patients

Quinolones can inhibit the metabolism of caffeine and may cause higher levels of circulating caffeine and side effects

23

1995

Spain

Prospective cohort

Liver impaired 33; normal liver 40

healthy individuals metabolise 3 mg IV caffeine faster than those with liver disease

24

2017

Greece

Prospective cohort

446 elective surgery patients

In patients with no previous history of headache, caffeine consumption was an additional independent factor for postoperative headache

25

1994

Denmark

Prospective observational

219 elective patients

The risk of postoperative headache was significantly greater in individuals with a daily caffeine intake > 400 mg/day

26

2003

United Kingdom

Prospective observational

208 day-casepatients

Caffeine is not a risk factor for perioperative headache

27

1989

New Zealand

Prospective survey

150 day-case patients

Patient who consume > 200 mg caffeine/day were 3-fold more likely to have a headache postoperatively compared to those who did not

28

1990

Netherlands

Prospective survey

334 GA + 75 LA

There was no difference between incidence of headache between GA or LA alone. Caffeine intake was not a risk factor for developing headache postoperatively.

29

1991

New Zealand

Prospective survey

287 patients undergoing minor elective surgery

postoperative headache is related to caffeine intake and that this relationship is explained at least in part, by a perioperative caffeine withdrawal syndrome

30

1993

USA

Prospective survey

233 surgical outpatients

Among daily caffeine drinkers, those who drank caffeinated beverages on the day of the surgical procedure had a lower incidence of postoperative headaches than did those who abstained (17% versus 28%; P < 0.04)

31

1994

Switzerland

Case report

Elective open abdominal surgery for oophorectomy

28F with postoperative headache, hemihypaesthesia, cerebral oedema on CT-Head which resolved with caffeine/ergometrine

32

1995

Switzerland

Prospective RCT

40 patients;

20 caffeine, 20 placebo

Surgical patients who have high caffeine intake were randomised to taking oral caffeine tablets or placebo. No patients on caffeine supplements develop headaches while 10 (50%) on placebo developed headaches which lasted up to 7 days.

33

1997

USA

Prospective RCT

234 elective surgical patients

prophylactic postoperative 200 mg IV caffeine decreased the incidence of headache

34

2019

United Kingdom

Prospective observational

40 ASA 1 individuals

high daily caffeine intake is associated with lower propofol requirements for induction. We hypothesise that those with high daily caffeine intake have lower arousal levels before surgery, because of a relative caffeine deficit secondary to being nil-by-mouth

39

1984

USA

Prospective RCT

60 patients undergoing CABG

Patients who drank > 3 cups of coffee/day, smoke > 40 cigarettes/day and drank 1–3 oz of alcohol required more fentanyl at induction for their CABG operation

40

1984

Australia

Prospective observational

23 patients + 23 controls

High caffeine intake resulted in worse cognitive functioning post anaesthetic compared to low caffeine intake

46

2011

USA

Case report

Elective tumour resection

The use of 500 mg IV caffeine intraoperatively to ensure the patient is responsive enough to perform intraoperative language mapping. Frequent stimulation-induced seizures thereafter limited further testing.

41

2017

USA

Case report

Elective dental procedure

Use of 60 mg IV caffeine in an 16yo male with trisomy 10 with a history of slow emergence from anaesthesia to speed up emergence from anaesthesia and as a respiratory stimulant

42

2010

Egypt

Prospective RCT

60 patients

30 caffeine, 30 control

Administration of 500 mg IV caffeine decreases the number of patients who developed adverse post extubation respiratory events and hastens recovery from sevoflurane anaesthesia.

45

2018

USA

Prospective RCT

8 male patients

15 mg/kg IV caffeine is able to accelerate emergence from isoflurane anaesthesia in healthy males without any apparent adverse effects

43

2018

USA

Retrospective observational

151 heavily sedated patients in the post-anaesthesia recovery area

Median of 150 mg IV caffeine may enhance the speed of recovery following general anaesthesia without any respiratory or cardiovascular changes

44

1996

USA

Prospective survey

882 nurses surveyed

85% of responders would withhold caffeine in patients after an acute myocardial infarction as a part of coronary precautions

35

2013

USA

Prospective RCT

30 patients

Ingestion of 102 mg of caffeine (drip coffee) can increase spontaneous voiding post indwelling bladder catheter removal

36

2013

USA

Prospective RCT

62 patients

500 mg IV caffeine given intraoperatively resulted in increased nausea, and there was no difference in postoperative headache, fatigue, time to discharge

37

2018

France

Prospective RCT

110 patients booked for heart valve surgery

400 mg caffeine q8h does not affect postoperative AF but does increase the risk of nausea and vomiting

38