Jean Guglielminotti

Risk factors for postoperative pneumonia after cardiac surgery and development of a preoperative risk score

Objectives:The aims of this study were, first, to identify risk factors for microbiology-proven postoperative pneumonia after cardiac surgery and, second, to develop and validate a preoperative scoring system for the risk of postoperative pneumonia. Design and Setting:A single-center cohort study. Patients:All consecutive patients undergoing cardiac surgery between January 2006 and July 2011. Interventions:None. Measurements and Main Results:Multivariate analysis of risk factors for postoperative pneumonia was performed on data from patients operated between January 2006 and December 2008 (training set). External temporal validation was performed on data from patients operated between January 2009 and July 2011 (validation set). Preoperative variables identified in multivariate analysis of the training set were then used to develop a preoperative scoring system that was validated on the validation set. Postoperative pneumonia occurred in 174 of the 5,582 patients (3.1%; 95% CI, 2.7–3.6). Multivariate analysis identified four risk factors for postoperative pneumonia: age (odds ratio, 1.02; 95% CI, 1.01–1.03), chronic obstructive pulmonary disease (odds ratio, 2.97; 95% CI, 1.8–4.71), preoperative left ventricular ejection fraction (odds ratio, 0.98; 95% CI, 0.96–0.99), and the interaction between RBC transfusion during surgery and duration of cardiopulmonary bypass (odds ratio, 2.98; 95% CI, 1.96–4.54). A 6-point score including the three preoperative variables then defined two risk groups corresponding to postoperative pneumonia rates of 1.8% (score < 3) and 6.5% (score ≥ 3). Conclusion:Assessing preoperative risk factors for postoperative pneumonia with the proposed scoring system could help to implement a preventive policy in high-risk patients with a risk of postoperative pneumonia greater than 4% (i.e., patients with a score ≥3).

The effect of preoperative heart rate and anxiety on the propofol dose required for loss of consciousness.

BACKGROUND: Conflicting results have been reported on the effect of anxiety on the propofol dose required for inducing loss of consciousness (LOC). The hemodynamic effects of anxiety, increased heart rate (HR), and cardiac output may account for these discrepancies. We therefore designed this study to address, first, the effect of perioperative HR on propofol dose required for LOC and, second, the effect of perioperative anxiety on HR. METHODS: Forty-five ASA physical status I-II female patients undergoing gynecological surgery were studied. Anxiety was assessed in the operating room with the State-Trait Anxiety Inventory (STAI)-state Spielberger scale (situational anxiety). After HR recording, anesthesia was induced with a 200-mL/h 1% propofol infusion with the Base Primea® pump (Fresenius-Vial, Brezins, France) until LOC. The propofol dose was recorded at the time of LOC. Relationships between STAI-state and HR versus propofol dose at LOC were tested with the Spearman test with a P value of 0.01. RESULTS: A significant relationship was observed between HR and propofol dose at LOC (&rgr; = 0.487, P = 0.0012) but not between STAI-state and propofol dose (&rgr; = 0.330, P = 0.0306). However, a significant relationship was observed between STAI-state and HR (&rgr; = 0.462 and P = 0.0054). CONCLUSION: Increased perioperative HR is associated with increased propofol dose required for LOC. Perioperative anxiety accounts for increased HR.

Prediction of Movement to Surgical Stimulation by the Pupillary Dilatation Reflex Amplitude Evoked by a Standardized Noxious Test

Background: Individual assessment of the amplitude of a physiologic reflex evoked by a standardized noxious test (SNT) before surgical stimulation has been suggested to predict movement upon the forthcoming surgical stimulation. This study aimed to compare the ability of pupillary dilatation reflex amplitude (PDRA) evoked by an SNT and estimated remifentanil effect-site concentration (Ce) to predict movement upon surgical stimulation. Methods: Eighty female patients were anesthetized for vacuum aspiration with propofol (Ce 4 &mgr;g/ml) and remifentanil. Remifentanil Ce was randomized to 0, 1, 3, or 5 ng/ml. SNT was a 60-mA, 5-s, 100-Hz tetanus applied on median nerve before cervix dilatation. PDRA was calculated as the difference in pupillary diameter after and before SNT. Movement upon cervix dilatation was recorded by an independent observer. Ability of PDRA and estimated remifentanil Ce to discriminate movers from non-movers during cervix dilatation was measured as the area under the receiver operating characteristics curve. Results: Twenty-one of the 76 patients analyzed moved during cervix dilatation. Mean PDRA (±1 SD) evoked by SNT was 2.0 ± 1.2 mm in movers and 0.6 ± 0.7 in non-movers (P < 0.0001). Remifentanil Ce was 0.2 ± 0.4 ng/ml in movers and 3.0 ± 1.7 in non-movers (P < 0.0001). Area under the receiver operating characteristics curve for PDRA was 0.90 (95% CI, 0.83 to 0.96) and for remifentanil Ce 0.94 (0.89 to 0.98), without any significant difference between the two areas. Conclusions: PDRA evoked by an SNT is as accurate as the estimated remifentanil Ce to predict movement upon cervix dilatation. PDRA could be valuable when estimated opioid Ce is not available or reliable.

Assessment of pain during labor with pupillometry: a prospective observational study.

BACKGROUND:Pain intensity is usually self-rated by patients with a numeric rating scale (NRS) but this scale cannot be used for noncommunicating patients. In anesthetized patients, experimental noxious stimulus increases pupillary diameter (PD) and pupillary light reflex amplitude (PLRA), the difference between PD before and after light stimulation. Labor pain is an intense acute nonexperimental stimulus, effectively relieved by epidural analgesia. In this prospective observational study, we therefore describe the effects of labor pain and pain relief with epidural analgesia on PD and PLRA, determine their association with pain intensity and determine the ability of a single measurement of PD or PLRA to assess pain. METHODS:In the first stage, pain (11-point NRS), PD, and PLRA were measured in 4 conditions in 26 laboring women: before and after epidural analgesia and in the presence and absence of a uterine contraction. Pupillometry values among the 4 conditions were compared, and the strength of the association between absolute values of pain and PD or PLRA and between pain and changes in PD or PLRA brought about by uterine contraction was assessed with r2. In the second stage, 1 measurement was performed in 104 laboring women. The strength of the association between pain and PD or PLRA was assessed with r2. The ability of PD or PLRA to discriminate pain (NRS > 4) was also assessed. RESULTS:In the first stage, a statistically significant increase in pain, PD, and PLRA was observed during a contraction, and this change was abolished after epidural analgesia. The r2 for the association between pain and changes in PD (r2 = 0.25 [95% confidence interval, 0.07–0.46] or PLRA (r2 = 0.34 [0.14–0.56]) brought about by a uterine contraction was higher than the r2 for the association between pain and absolute values of PD (r2 = 0.14 [0.04–0.28]) or PLRA (r2 = 0.22 [0.10–0.37]) suggesting a stronger association for changes than for absolute values. In the second stage, r2 was 0.23 [0.10–0.38] for PD and 0.26 [0.11–0.40] for PLRA and the area under the receiver operating characteristics curve was 0.82 [0.73–0.91] and 0.80 [0.71–0.89], respectively. CONCLUSIONS:Changes in PD and PLRA brought about by a uterine contraction may be used as a tool to assess analgesia in noncommunicating patients.

Temporal trends in anesthesia-related adverse events in cesarean deliveries, New York State, 2003-2012

Background: Cesarean delivery (CD) is associated with significantly increased risks of anesthesia-related adverse events (ARAEs) and nonanesthetic perioperative morbidity compared with vaginal delivery. Temporal trends in these adverse outcomes remain unknown despite efforts to improve maternal safety. This study examines temporal trends in ARAEs and nonanesthetic perioperative complications in CDs in New York hospitals. Methods: Data are from the State Inpatient Database for New York, 2003–2012. ARAEs, including minor and major ARAEs, and nonanesthetic perioperative complications were identified through International Classification of Diseases, Ninth Revision, Clinical Modification codes. Statistical significance in time trends was assessed using the Cochran–Armitage test and multivariable logistic regression. Results: Of the 785,854 CDs studied, 5,715 (730 per 100,000; 95% CI, 710 to 750) had at least one ARAE and 7,040 had at least one perioperative complication (890 per 100,000; 95% CI, 870 to 920). The overall annual rate of ARAEs decreased from 890 per 100,000 in 2003 to 660 in 2012 (25% decrease; 95% CI, 16 to 34; P < 0.0001). The rate of minor ARAEs decreased 23% (95% CI, 13 to 32) and of major ARAEs decreased 43% (95% CI, 23 to 63). No decrease was observed in the rate of ARAEs for CDs performed under general anesthesia. The rate of nonanesthetic complications increased 47% (95% CI, 31 to 63; P < 0.0001). Conclusions: Anesthesia-related outcomes in cesarean deliveries appear to have improved significantly across hospitals in New York in the past decade. Perioperative nonanesthetic complications remain a serious healthcare issue.

Marfan's syndrome during pregnancy: anesthetic management of delivery in 16 consecutive patients.

BACKGROUND:Marfan’s syndrome is characterized by progressive dilatation of the aortic root. This dilatation is accelerated by pregnancy, exposing patients to an increased risk of aortic dissection. Literature on the anesthetic management of delivery in patients with Marfan’s syndrome consists only of case reports. We therefore conducted a retrospective review of medical records focusing on anesthetic management of delivery in patients with Marfan’s syndrome in a national referral center. METHODS:We reviewed the medical records of all pregnant women with Marfan’s syndrome who were followed at their institution over a 6-year period. RESULTS:Sixteen pregnancies in 15 patients were analyzed. The initial aortic root diameter was larger than 40 mm in 9 patients and larger than 45 mm in 1 patient. Two patients did not receive &bgr;-blockers throughout pregnancy because of poor tolerance. One patient with an aortic root diameter of 47 mm did not receive &bgr;-blocker before 33 weeks’ gestation because of late referral. This woman developed acute type 1 aortic dissection at 37 weeks, requiring emergency cesarean delivery under general anesthesia followed by aortic repair. Thirteen other patients underwent cesarean delivery, 1 under spinal anesthesia and 12 under general anesthesia. General anesthesia management included close arterial blood pressure monitoring, avoidance of high blood pressure, administration of opioids before delivery, and titrated nicardipine administration. Two patients (including one with intrauterine fetal death) underwent vaginal delivery under epidural analgesia. There were no maternal deaths. CONCLUSIONS:Pregnant women with Marfan’s syndrome who received care in a multidisciplinary tertiary care setting that included active peripartum involvement of anesthesiologists had good clinical outcomes.

Pain assessment in the postanaesthesia care unit using pupillometry: A cross-sectional study after standard anaesthetic care.

BACKGROUND Patients assess their own pain with a numerical rating scale (NRS). In the postanaesthesia care unit (PACU), NRS helps to determine and monitor analgesic administration, but is useless in patients who are unable to communicate. In non-PACU patients, acute pain increases pupillary diameter and pupillary light reflex amplitude (PLRA), the difference between pupillary diameter before and after light stimulation. OBJECTIVES To study the association between postoperative pain (NRS) and pupillary diameter or PLRA in PACU patients after routine anaesthetic care. DESIGN Cross-sectional cohort study. SETTING Bichat-Claude Bernard Hospital, Paris. PATIENTS One hundred and forty-five patients undergoing planned surgery under general anaesthesia. INTERVENTIONS NRS, pupillary diameter and PLRA were measured on arrival in the PACU. When NRS was more than 4, intravenous morphine titration was started and a second measurement performed. MAIN OUTCOME MEASURES Association between NRS and pupillary diameter or PLRA was assessed with Pearson correlation coefficient (r) as was association between changes in these variables after morphine titration. RESULTS Mean NRS was 4.7, and was more than 4 in 79 patients (55%). No statistically significant association was observed between NRS and pupillary diameter (r = 0.10, P = 0.54) or PLRA (r = 0.03, P = 0.72). Twenty-seven patients (19%) received morphine titration with significant decreases in NRS, pupillary diameter and PLRA afterwards. No association was observed between NRS changes and pupillary diameter or PLRA changes. CONCLUSION Acute postoperative pain is not associated with pupillary diameter or PLRA. Further research is required to develop tools to assess pain in the PACU.

Hyponatremia after hip arthroplasty may be related to a translocational rather than to a dilutional mechanism.

ObjectivePostoperative hyponatremia is a frequent metabolic disturbance that may cause life-threatening complications. It results from both a positive electrolyte-free water (EFW) balance and an antidiuretic hormone release. During surgery, intracellular solutes may leak out of cells because of an increased membrane permeability leading to increased osmolality, cellular water shift, and redistribution hyponatremia, a concept coined the sick cell syndrome. Because of release of osmotically active solutes, plasma or urinary osmolar gap should increase. Therefore, we tested the hypothesis that postoperative hyponatremia may be related to a translocational mechanism evidenced by a postoperative increase of the osmolar gap rather than to a positive EFW balance. SettingAn anesthesiology department in a 1,200-bed university hospital. DesignA 5-month prospective observational study. SubjectsThirty-three consecutive patients undergoing elective hip arthroplasty under general anesthesia. They were divided into two groups whether the postoperative plasma sodium concentration decrease was ≥2 mmol/L (group 1) or <2 mmol/L (group 2). MeasurementsPlasma sodium concentration ([Na+]p) and plasma osmolality were measured before induction of anesthesia and at skin closure. Osmolality was calculated at the same times. Plasma osmolar gap (OGp) was calculated as the difference between measured and calculated osmolality. Postoperative urinary osmolar gap (OGu) was calculated in the same way. EFW balance was calculated as the ratio of (infused EFW − excreted urinary EFW) to total body water. ResultsIn 33 patients, a significant [Na+]p decrease of −2.0 was observed. No relationship was demonstrated between EFW balance and perioperative [Na+]p variation (r = .28;p = .12). A relationship was observed between perioperative OGp variation and perioperative [Na+]p variation (r = .74;p < .0001). In the 19 group 1 patients, [Na+]p decreased by −3.0 mmol/L. EFW balance did not differ between group 1 and group 2 patients. No statistical relationship was observed between EFW balance and perioperative [Na+]p variation in group 1 (r = .20;p = .40) and in group 2 (r = .43;p = .14). OGp increased only in group 1 but not in group 2 patients, and postoperative OGu was greater in group 1 than in group 2 patients. A relationship was observed between perioperative OGp variation and perioperative [Na+]p variation in group 1 (r = .53;p = .02) but not in group 2 (r = .32;p = .26). ConclusionHyponatremia after hip arthroplasty may not be related to a positive EFW balance. The postoperative increase of the OGp and the greater postoperative OGu in patients developing postoperative hyponatremia suggest the release of osmotically active solutes leading to cellular water shift from intracellular to extracellular spaces. These data may support the clinical relevance of the sick cell syndrome in the postoperative context.

Monitoring Obstetric Anesthesia Safety across Hospitals through Multilevel Modeling

Background:The rate of anesthesia-related adverse events (ARAEs) is recommended for monitoring patient safety across hospitals. To ensure comparability, it is adjusted for patients’ characteristics with logistic models (i.e., risk adjustment). The rate adjusted for patient-level characteristics and hospital affiliation through multilevel modeling is suggested as a better metric. This study aims to assess a multilevel model-based rate of ARAEs. Methods:Data were obtained from the State Inpatient Database for New York 2008–2011. Discharge records for labor and delivery and ARAEs were identified with International Classification of Diseases, Ninth Revision, Clinical Modification codes. The rate of ARAEs for each hospital during 2008–2009 was calculated using both the multilevel and the logistic modeling approaches. Performance of the two methods was assessed with (1) interhospital variability measured by the SD of the rates; (2) reclassification of hospitals; and (3) prediction of hospital performance in 2010–2011. Rankability of each hospital was assessed with the multilevel model. Results:The study involved 466,442 discharge records in 2008–2009 from 144 hospitals. The overall observed rate of ARAEs in 2008–2009 was 4.62 per 1,000 discharges [95% CI, 4.43 to 4.82]. Compared with risk adjustment, multilevel modeling decreased SD of ARAE rates from 4.7 to 1.3 across hospitals, reduced the proportion of hospitals classified as good performers from 18% to 10%, and performed similarly well in predicting future ARAE rates. Twenty-six hospitals (18%) were nonrankable due to inadequate reliability. Conclusion:The multilevel modeling approach could be used as an alternative to risk adjustment in monitoring obstetric anesthesia safety across hospitals.

Reporting and Methodology of Multivariable Analyses in Prognostic Observational Studies Published in 4 Anesthesiology Journals: A Methodological Descriptive Review.

BACKGROUND: Prognostic research studies in anesthesiology aim to identify risk factors for an outcome (explanatory studies) or calculate the risk of this outcome on the basis of patients’ risk factors (predictive studies). Multivariable models express the relationship between predictors and an outcome and are used in both explanatory and predictive studies. Model development demands a strict methodology and a clear reporting to assess its reliability. In this methodological descriptive review, we critically assessed the reporting and methodology of multivariable analysis used in observational prognostic studies published in anesthesiology journals. METHODS: A systematic search was conducted on Medline through Web of Knowledge, PubMed, and journal websites to identify observational prognostic studies with multivariable analysis published in Anesthesiology, Anesthesia & Analgesia, British Journal of Anaesthesia, and Anaesthesia in 2010 and 2011. Data were extracted by 2 independent readers. First, studies were analyzed with respect to reporting of outcomes, design, size, methods of analysis, model performance (discrimination and calibration), model validation, clinical usefulness, and STROBE (i.e., Strengthening the Reporting of Observational Studies in Epidemiology) checklist. A reporting rate was calculated on the basis of 21 items of the aforementioned points. Second, they were analyzed with respect to some predefined methodological points. RESULTS: Eighty-six studies were included: 87.2% were explanatory and 80.2% investigated a postoperative event. The reporting was fairly good, with a median reporting rate of 79% (75% in explanatory studies and 100% in predictive studies). Six items had a reporting rate <36% (i.e., the 25th percentile), with some of them not identified in the STROBE checklist: blinded evaluation of the outcome (11.9%), reason for sample size (15.1%), handling of missing data (36.0%), assessment of colinearity (17.4%), assessment of interactions (13.9%), and calibration (34.9%). When reported, a few methodological shortcomings were observed, both in explanatory and predictive studies, such as an insufficient number of events of the outcome (44.6%), exclusion of cases with missing data (93.6%), or categorization of continuous variables (65.1%.). CONCLUSIONS: The reporting of multivariable analysis was fairly good and could be further improved by checking reporting guidelines and EQUATOR Network website. Limiting the number of candidate variables, including cases with missing data, and not arbitrarily categorizing continuous variables should be encouraged.