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Introduction Laboratory testing is done before surgery to identify body abnormalities that cannot be detected through clinical evaluation alone. Patients going in for low- or intermediate-risk surgeries are often encouraged to undergo a battery of tests as usual. This cross-sectional observational study evaluated the status of routine pre-operative laboratory tests in American Society of Anaesthesiologists (ASA) Grade I, II, and III adults undergoing elective surgery at a maternity hospital, as well as the impact of these tests on the outcome of the pre-anaesthetic check-up (PAC). Methods The present observational study was conducted on 500 patients scheduled for elective surgery under anaesthesia. The procedures included routine gynaecological and obstetric surgeries like abdominal hysterectomy, suction evacuation, laparotomy for ectopic pregnancy, diagnostic biopsy, and lower segment caesarean section, among others. A designated anaesthesiologist gathered information from the completed PAC sheets. As per the standard departmental policy, each patient underwent a clinical examination and routine investigations at the PAC clinic. In addition to demographic and other variables, laboratory test results and any peri-operative interventions performed due to abnormalities were assessed. Investigations already done, asked by anaesthesiologists, and referral services sought were noted. The impact of these investigations on anaesthetic decision-making was noted. Data were expressed in frequencies and percentages and statistically analysed using INSTAT software (GraphPad Prism Software Inc., La Zolla, USA). Results The age and weight of the patients range from 20 to 70 years and 55 to 95 kg. Most patients belonged to ASA Grade II (n=348, 69.6%). Hypothyroidism was the most common abnormal finding (n=122, 22.4%). Anaemia, hypertension, and diabetes were detected in n=8 (1.6%), n=82 (16.4%), and n=34 (6.8%) of patients, respectively. In 488 (97.6%) patients, one or more of the investigations from the list were pending. Based on the results of various preoperative laboratory investigations, 87 (17.4%) patients were advised of multiple specialty opinions before surgery. A total of 453 (90.6%) patients attending the clinic were recommended to review their PACs after their pending investigations and specialist consultations were completed. At the same time, n=41 (8.2%) was found to be fit for surgery, and n=6 (1.2%) was found unfit for surgery and was postponed. Conclusions The incidence of tests with abnormal results was a little high in our study. One reason could be that a particular group of patients is included in the study. Preoperative laboratory investigations substantially increase the costs. Not many patients with abnormal tests may require changes in their peri-anaesthetic management. Nonetheless, laboratory tests can help ensure the patient is in an ideal preoperative condition. Pre-operative laboratory investigations should be advised on a case-by-case basis to avoid inconveniencing the patient, delaying the surgical procedure, and driving up the cost of surgical treatment.
RESUMO
The estimation of electrolytes like sodium (Na(+)), potassium (K(+)) and chloride (Cl(-)) using direct and indirect ion-selective electrodes (ISE) is a routine laboratory practice. Interferents like proteins, triglycerides, drugs etc. are known to affect the results. The present study was designed to look into the effect of increasing glucose concentrations on estimation of Na(+), K(+) and Cl(-) by direct and indirect ISE. Pooled sera was mixed with glucose stock solution (20 g/dL) prepared in normal saline to obtain glucose concentrations ranging from ~100 to ~5000 mg/dL. Na(+), K(+) and Cl(-) levels were estimated by direct and indirect ISE analyzers and results were statistically analysed using ANOVA and Pearson's correlation. Similar experiment was also performed in 24 h urine sample from healthy subjects. Significant difference was observed between Na(+) and Cl(-) measurements by direct and indirect ISE, with indirect ISE values being consistently higher than direct ISE. Besides this, significant difference was observed amongst Na(+) and Cl(-) values from baseline values obtained by indirect ISE at glucose concentrations ≥2486 mg/dL. However, no such difference was observed with direct ISE. Na(+) and Cl(-) estimation by indirect ISE showed significant negative correlation with glucose concentration, more so, above ~2000 mg/dL. K(+), however, showed no significant difference with varying glucose. Similar results were observed in 24 h urine samples with a significant difference observed amongst Na(+) and Cl(-) values at ≥2104 mg/dL glucose. Thus we conclude that high glucose concentrations interfere significantly in estimation of Na(+) and Cl(-) by indirect ISE in serum as well as urine.