Intraoperative hypotension and delirium after on-pump cardiac surgery
Delirium is a common complication after cardiac surgery and may be as a result of inadequate cerebral perfusion. We studied delirium after cardiac surgery in relation to intraoperative hypotension (IOH).
This observational single-centre, cohort study was nested in a randomized trial, on a single intraoperative dose of dexamethasone vs placebo during cardiac surgery. During the first four postoperative days, patients were screened for delirium based on the Confusion Assessment Method (CAM) for Intensive Care Unit on the intensive care unit, CAM on the ward, and by inspection of medical records. To combine depth and duration of IOH, we computed the area under the curve for four blood pressure thresholds. Logistic regression analyses were performed to investigate the association between IOH and the occurrence of postoperative delirium, adjusting for confounding and using a 99% confidence interval to correct for multiple testing.
Of the 734 included patients, 99 patients (13%) developed postoperative delirium. The adjusted Odds Ratio for the Mean Arterial Pressure <60 mm Hg threshold was 1.04 (99% confidence interval: 0.99–1.10) for each 1000 mm Hg2 min2 AUC2 increase. IOH, as defined according to the other three definitions, was not associated with postoperative delirium either. Deep and prolonged IOH seemed to increase the risk of delirium, but this was not statistically significant.
Independent of the applied definition, IOH was not associated with the occurrence of delirium after cardiac surgery.
Impact of intraoperative hypotension and blood pressure fluctuations on early postoperative delirium after non-cardiac surgery
Postoperative delirium is common in older patients. Despite its prognostic significance, the pathophysiology is incompletely understood. Although many risk factors have been identified, no reversible factors, particularly ones potentially modifiable by anaesthetic management, have been identified. The goal of this prospective cohort study was to investigate whether intraoperative hypotension was associated with postoperative delirium in older patients undergoing major non-cardiac surgery.
Study subjects were patients >65 years of age, undergoing major non-cardiac surgery, who were enrolled in an ongoing prospective observational study of the pathophysiology of postoperative delirium. Intraoperative blood pressure was measured and predefined criteria were used to define hypotension. Delirium was measured by the Confusion Assessment Method on the first two postoperative days. Data were analysed using t-tests, two-sample proportion tests and ordered logistic regression multivariable models, including correction for multiple comparisons.
Data from 594 patients with a mean age of 73.6 years (
sd6.2) were studied. Of these 178 (30%) developed delirium on day 1 and 176 (30%) on day 2. Patients developing delirium were older, more often female, had lower preoperative cognitive scores, and underwent longer operations. Relative hypotension (decreases by 20, 30, or 40%) or absolute hypotension [mean arterial pressure (MAP)<50 mm Hg] were not significantly associated with postoperative delirium, nor was the duration of hypotension (MAP<50 mm Hg). Conversely, intraoperative blood pressure variance was significantly associated with postoperative delirium. Discussion
These results showed that increased blood pressure fluctuation, not absolute or relative hypotension, was predictive of postoperative delirium.
- Stoelting's Pharmacology and Physiology in Anesthetic Practice
- NAP5: aware of the limitations
Peripheral nerve catheters in children: an analysis of safety and practice patterns from the pediatric regional anesthesia network (PRAN)
Peripheral nerve catheters (PNCs) are used with increasing frequency in children. Although adult studies have demonstrated safety with this technique, there have been few safety studies in children. The main objective of the current investigation was to examine the incidence of PNC complications in children undergoing surgery.
This is an observational, multi-institutional study using the Pediatric Regional Anesthesia Network (PRAN) database. Data pertaining to PNCs were entered prospectively into a secure, online database by each participating centre. Patient characteristics, anatomic location, localization techniques, medications used, and complications were recorded for each catheter. All complications and any sequelae were followed until resolution.
There were 2074 PNCs included in the study. 251 adverse events and complications were recorded, resulting in an overall incidence (95% CI) of complications of 12.1% (10.7–13.5%). The most common complications were catheter malfunction, block failure, infection, and vascular puncture. There were no reports of persistent neurologic problems, serious infection, or local anaesthetic systemic toxicity, resulting in an estimated incidence (95% CI) of 0.04% (0.001–0.2%). Patients who developed an infection had used the catheters for a greater number of days, median (IQR) of 4.5 (3–7) days compared with 3 (1–3) days in the patients who did not develop an infection, P<0.0001.
Our data support the safety of placing PNCs in children, with adverse event rates similar to adult studies. Catheter problems are common, yet minor, in severity.
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- Practical details, confirmed safety and new targets
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Fentanyl-induced cough is a risk factor for postoperative nausea and vomiting
Postoperative nausea and vomiting (PONV) and fentanyl-induced cough (FIC) are two common anaesthesia-related events, which seem to have common risk factors. In this prospective cohort study, we investigate whether patients who have FIC during induction of anaesthesia have an increased incidence of PONV.
We studied adult non-smoking gynaecological surgical patients enrolled between July 1, 2011 and July 30, 2012. The presence of FIC during induction and the occurrence of PONV were recorded. Fentanyl-induced cough and other perioperative variables were subjected to multivariate analysis to determine the association between FIC and PONV.
All 502 patients enrolled in this study had at least two risk factors for PONV, and 154 (31%) developed FIC. The incidence of PONV in the FIC group was higher than in the non-FIC group (56.5 vs 38.2%; P<0.0001). Multivariate logistic regression analysis found FIC to be a predictive risk factor for the development of PONV (adjusted odds ratio 2.08, 95% confidence interval 1.41–3.07).
Non-smoking women undergoing gynaecological surgery who develop FIC during induction of anaesthesia have a higher incidence of PONV.
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