The impact of bolus versus continuous infusion of intravenous ketamine on bispectral index variations and desflurane administration during major surgery: The KETABIS study.

BACKGROUND: Although ketamine, a NMDA-receptor antagonist, tends to increase the bispectral index (BIS), it remains a widely used analgesic whenever administered in low doses during major surgery. OBJECTIVE: The objective of this study was to compare the impact of intravenous ketamine (given either as a continuous infusion or as a bolus) on BIS and to compare desflurane administration and postoperative outcomes between the groups. DESIGN: Prospective, randomised, parallel-group, open-label study. SETTING: University hospital, operating room. PARTICIPANTS: Fifty patients, scheduled for major abdominal surgery. INTERVENTIONS AND MAIN OUTCOMES MEASURES: Patients were randomised into two groups: ketamine by intravenous continuous infusion - group (KI) and ketamine by i.v. bolus - group (KB). In the KI group, ketamine at a rate of 0.25 mg kg-1 h-1 was commenced at skin incision (T0) and maintained at this rate for the duration of surgery. In group KB, a ketamine bolus of 0.25 mg kg-1was administered at T0 and repeated every hour. The difference in BIS between the groups was compared from T0 onwards. The amount of desflurane administered to keep BIS within the usual recommended range (40-60) was compared, as were the doses of phenylephrine and remifentanil. Postoperative pain and recovery outcomes were also assessed. RESULTS: After T0, the BIS increased significantly from baseline in group KB compared with group KI: the rise in BIS was 20 ±â€Š8 vs. 11 ±â€Š6, respectively (P = 0.0001). The between-group mean difference (95% confidence interval (CI), was 9 (5 to 13). In group KB, desflurane administration significantly increased for the first 15 min after T0: 6.3 ±â€Š1.8 vs. 3.8 ±â€Š1.3 ml (P < 0.0001) with a mean intergroup group difference (95% CI) of 2.4 (1.5 to 3.4) ml. There was no difference in desflurane administration when considering the full hour from T0 to T60 min: 16 ±â€Š9 vs. 15 ±â€Š5 ml (P = 0.63) with a mean intergroup difference (95% CI) of 1 (-3 to 5) ml. After surgery, pain scores, opioid consumption, incidence of nausea and vomiting and recovery scores were similar between groups. CONCLUSION: Compared with a continuous ketamine infusion, a ketamine bolus significantly increased the BIS after T0. In order to keep the BIS below 60, significantly more desflurane was administered from T0 to T15 min in group KB. To prevent such higher desflurane administration and its related atmospheric pollution, our results suggest administering intra-operative intravenous ketamine as an infusion rather than a bolus. TRIAL REGISTRATION: Clinicaltrials.gov registration identifier: NCT03781635.

Chronic periodontitis is associated with platelet factor 4 (PF4) secretion: A pilot study.

AIM: Platelets contribute to chronic inflammation, but their role in periodontitis is not well understood. The aim of this study was to compare platelet recruitment and activation in healthy and inflamed periodontium. MATERIALS AND METHODS: Gingival crevicular fluid (GCF) samples were obtained from sites of healthy periodontium, gingivitis and periodontitis. Platelets were quantified in the GCF by staining and microscopy. GCF concentrations of platelet factor 4 (PF4) [PF4]GCF and glycoprotein IIbIIIa ([GPIIbIIIa]GCF ) were determined by ELISA. Blood samples were obtained from the three patient groups. Platelets were isolated from whole blood and stimulated with lipopolysaccharide (LPS) from Porphyromonas gingivalis to evaluate and compare the LPS-induced PF4 release. RESULTS: Compared to controls, platelet recruitment was increased at gingivitis and periodontitis sites, based on platelet counts and [GPIIbIIIa]GCF . [PF4]GCF was elevated in periodontal pockets but not at gingivitis or healthy sites. Circulating plasma levels of PF4 were higher in patients with generalized severe periodontitis (SP), compared to patients with gingivitis or healthy periodontium. Platelets isolated from SP patients contained and released more PF4 in response to P. gingivalis LPS than platelets from gingivitis or periodontally healthy patients. CONCLUSIONS: Periodontitis is associated with increased platelet activation and PF4 release, both locally and systemically.