Journal of the New Zealand Medical Association, 22-August-2008, Vol 121 No 1280
Post-procedure surveillance in liver biopsy: how long is long enough?
Rowena Howard, George Karageorge, Kate van Harselaar, Melanie Bell, Pete Basford, Michael Schultz, Sarah Derrett
Liver biopsy is the current gold standard for assessing chronic liver disease. It is, however, an invasive and costly procedure associated with complications. Research into less invasive methods of assessing liver fibrosis1 is still inconclusive, and these methods have not yet been routinely implemented.
The most common indications for liver biopsy are viral hepatitis and abnormal liver function tests.2 Other indications include haemochromatosis, methotrexate monitoring, and assessment for malignancy.3
Major complications of liver biopsy such as bleeding and visceral perforation are rare—occurring in less than 1% of patients—but the procedure is associated with an overall mortality rate of 0.01–0.17%.2,3,4–7 Minor complications such as pain, vasovagal episode, nausea, and vomiting occur more frequently in up to 35% of patients.4,8,9
Shorter observation periods after biopsy have been suggested.10 In a recent American study of more than 3000 patients, the post-procedure observation was consecutively reduced from 6 hours to 1 hour over a 9-year period, as the majority of complications were found to occur within 1 hour of the procedure.11 Economic advantages of shorter observation periods have been reported.10,11
To our knowledge, an ideal observation time before discharge has not been studied in New Zealand. The situation in New Zealand is unique as the population being served by secondary and tertiary hospitals is often rural and many patients do not have ready access to health care providers once discharged.
This study aims to:
Percutaneous liver biopsy—At Dunedin Public Hospital (DPH), a single consultant has been overseeing the liver biopsies during the observation period. Current blood results (full blood count and INR) were reviewed and informed consent obtained one day prior to the procedure. For the procedure, patients were placed in the supine position, and the ideal location for the liver biopsy on the lateral lower aspect of the right thorax was established both by percussion as well as immediately prior to the investigation by means of a 3.5MHz sector ultrasound probe (Sonolayer-LS SAL 5AS, Toshiba Medical Systems Corporation, Japan).
From 2005 onwards following disinfection of the skin with iodine, pethidine (50 mg iv, Mayne Pharma [NZ] Limited, Wellington, NZ) was given for pain control. The skin and various layers of the thoracic wall were then locally anaesthetised with 5–10 ml of 1% lignocaine containing 1:100,000 adrenaline (Astra Zenica, Auckland, NZ). A small incision into the skin was made using a disposable scalpel (Swann-Morton, Sheffield, UK) before the biopsy was performed using a modified Menghini biopsy set (17/16 G, TSK Laboratory, Japan).
After the procedure, patients were placed on their right-hand-side to rest on a sandbag for 1 hour, followed by 4 hours lying flat and a final 1 hour sitting. Blood pressure, pulse, and wound site were checked every 15 minutes for the first hour and thereafter hourly until the time of discharge. If pain was experienced, based on the severity, either pethidine 50mg i.v. or paracetamol 1g p.o. was administered. Patients living beyond a 40-minute driving radius of DPH were asked to stay close to DPH overnight after discharge.
Study population—Following ethical approval, a retrospective audit of percutaneous liver biopsies was undertaken at DPH. DPH is a tertiary teaching hospital with 350 inpatient beds. For specialised services such as gastroenterology it serves a population of more than 190,000 people usually resident in Otago province.12 Otago is the second largest province of New Zealand and covers approximately 32,000 square kilometres of land in the lower South Island.
Data collection—Unique patient identifiers (National Health Index numbers) of patients having a liver biopsy between 1 January 2001 and 31 December 2006 were extracted from the DPH Information Services. Medical files were then obtained and analysed. Patients having CT or ultrasound-guided biopsies organised by other teams, and biopsies undertaken during abdominal operations, were excluded from analysis.
Data collected included age, sex, indication for biopsy, and date of biopsy. Also, data was collected from patients’ files regarding the administration, type, and timing of post-procedural analgesia. Peri- and post-procedural complications, and the timing of their occurrence, were recorded for analysis if pain was noted in the patient file, analgesia was administered, or any other complication was noted.
Statistical methods—Descriptive statistics were computed for patient characteristics. Chi-squared tests of proportions were used to compare various outcomes for those who had pre-biopsy analgesia with those who did not. All statistical analyses were carried out in SAS v9.1 software.13
493 liver biopsies were carried out between 2001 and 2006. Of these, 447 were included in the study. Reasons for exclusion of biopsies from the study are presented in Table 1. There were 428 patients included in the study, of whom 15 patients received more than one biopsy (to a maximum of four biopsies per patient) during the study period.
Table 1. Reasons for exclusion from study
Patient characteristics—The majority of patients were aged between 40 and 60 years (see Table 2), with more men than women undergoing biopsies. The main indication for percutaneous biopsy was hepatitis C, followed by abnormal liver function tests and methotrexate therapy.
Complications—Table 3 shows complications and the timing of post-procedure analgesia administration. No complications were reported for 69% of the biopsies performed. Two patients had two complications (pain and hypotension) and one patient had pain, hypotension, and nausea.
There were 139 biopsies (134 patients) where analgesia was administered at least once post-procedurally; 4 patients were given analgesia twice post-procedurally; and 1 patient was given analgesia three times. Opiates were administered 68% of the time post-procedurally.
A greater proportion of females had complications than males: 47% and 31% respectively (95% CI for the difference: 6% to 25%, p=0.0009).
Only 11 complications other than pain were recorded. Of these, the time period of complication occurrence was unreported for 3 patients; for the remaining 8, complications occurred within 2 hours of biopsy.
Table 2. Patient characteristics and indications for percutaneous biopsy
*All biopsies shown, including repeats; †e.g. sarcoidosis, metabolic syndrome, systemic lupus erythmatosis, raised ferritin, portal hypertension.
Table 3. Complications and the timing of post-procedural analgesia administration
*One record is missing pre-procedural analgesia; **All complications are shown.
Effects of pre-procedural pethidine—Pre-procedural pethidine was given to 130 patients (29.2%). The proportion of those that experienced complications with and without pre-procedural pethidine were 34% and 39% respectively (95% CI for the difference -4% to 15%, p=0.29). The rates of pre-biopsy pethidine was 31% for females and 28% for males (95% CI for the difference -6% to 11%, p=0.52).
The proportion of those who required analgesia with and without pre-procedural pethidine were 31% and 32% respectively (95% CI for the difference -10% to 9%, p=0.92).
Of those who received postoperative analgesia, a smaller proportion of patients received opiates post-procedure when given pre-procedural pethidine compared to the group not receiving pre-procedural pethidine, 49% and 77% respectively (95% CI for the difference 10% to 45%, p=0.0014).
Despite recent advances in non-invasive tests to determine the stage of liver fibrosis, percutaneous liver biopsy remains the gold standard. The invasive nature of this procedure carries the risk of complications necessitating a period of observation after biopsy. Determining the ideal length of this observation period has not yet been ascertained, particularly in countries with a large rural population.
This retrospective study of 493 biopsies demonstrated that patient characteristics and indications for biopsy are similar in New Zealand when compared with international studies.2,4 No major complications were experienced. The use of pre-procedural ultrasound to identify the ideal location for all biopsies, and the less traumatic low-gauge Menghini technique in combination with a single consultant overseeing the liver biopsies at our unit, may contribute to this.14 Minor complications, predominantly pain, were recorded for less than one third of patients, which is comparable to similar international studies.4,8,9
Administration of pre-procedural pethidine did not affect the rate of complications. A smaller proportion of patients receiving pre-procedural pethidine received post-procedural opiates as compared to those who did not receive pre-procedural pethidine. Clinically, pethidine is reported to reduce pre-procedural anxiety. Further research is required to determine the best use of prophylactic opiates for percutaneous liver biopsy.
The post-procedural observation period is a major factor in the overall cost of biopsy to the health system; but cost savings need to be weighed against risks to patients. Our study found that the majority of complications occurred within two hours of the procedure.
In summary, based on our retrospective findings, we suggest reducing the post-procedure observation period for percutaneous liver biopsies to 2 hours warrants consideration. It remains unclear if early discharge and therefore mobilisation of patients will lead to an increase of pain or other complications, but the overall practicality of this management is supported by the finding that no late major complications or early re-admissions occurred during the study periods.
We did not identify any major complications in our study, and cannot therefore comment on the timing of such. Nevertheless, in Otago, because of the rural environment, the current policy of patients from rural areas remaining within a 40-minute driving radius of the hospital overnight ought to be maintained.
Competing interests: None known.
Author information: Rowena Howard, George Karageorge, and Kate van Harselaar: Trainee Interns, Department of Preventive and Social Medicine, University of Otago, Dunedin; Melanie Bell, Senior Lecturer, Department of Preventive and Social Medicine, University of Otago, Dunedin; Pete Basford, Registrar, Department of Gastroenterology, Otago District Health Board, Dunedin; Michael Schultz, Senior Lecturer and Consultant Gastroenterologist, Department of Medical and Surgical Sciences, University of Otago, Dunedin; Sarah Derrett: Senior Research Fellow, Department of Preventive and Social Medicine, University of Otago, Dunedin
Acknowledgements: We are most grateful to the other members of the trainee intern group who contributed to the design and data collection (Ivor Cormack, Lara Colbourne, Michael Hamilton, Victor Kong, and Ben La Hood) as well as Dr Ralf Lubcke (Gastroenterologist at the Otago District Health Board) for his helpful comments.
Correspondence: Dr Michael Schultz, Department of Medical and Surgical Sciences, University of Otago, PO Box 913, Dunedin, New Zealand. Fax: +64 (0)3 4747724; email: email@example.com
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