Nicole M. Zimmerman

Pharyngeal Oxygen Insufflation During Airtraq Laryngoscopy Slows Arterial Desaturation in Infants and Small Children

BACKGROUND:The extent to which insufflation of oxygen into the posterior pharynx during laryngoscopy prolongs adequate saturation in infants and small children remains unknown. Therefore, we compared oxygen saturation over time in preoxygenated small children with and without posterior pharynx oxygen insufflation. METHODS:After induction of anesthesia with sevoflurane and propofol, infants and small children were preoxygenated with 100% oxygen for 3 minutes. An AirTraq laryngoscope size 0 or 1 with an appropriately sized cuffed endotracheal tube positioned in the side channel was prepared. Oxygen tubing was connected to the endotracheal U-shaped tube. However, oxygen at a flow of 4 L/min was provided only to half of the randomly selected participating patients. The trachea was intubated, the tube cuff was inflated, and the laryngoscope was removed from the mouth. The oxygen tubing was disconnected from the endotracheal tube and left exposed to ambient air until oxygen saturation decreased to 95%. Thereafter, patients’ lungs were manually ventilated with 100% oxygen until SpO2 returned to 100%. Subsequent anesthetic management was at the discretion of the attending anesthesiologist. RESULTS:Laryngoscopy took a median of 60 (Q1–Q3, 40–90) seconds. The mean time to 95% oxygen saturation was (mean ± SD) 166 ± 47 seconds in the oxygen insufflation group and 131 ± 39 seconds in small children without insufflation. Oxygen insufflation prolonged the mean time for saturation to decrease from 100% to 95% by an estimated 35 (95% confidence interval, 10–60) seconds, P = 0.01. CONCLUSIONS:Adding posterior pharyngeal oxygen insufflation to conventional preoxygenation prolonged the period of adequate oxygen saturation in infants and small children by an amount that is potentially clinically important.

Period-dependent Associations between Hypotension during and for Four Days after Noncardiac Surgery and a Composite of Myocardial Infarction and DeathA Substudy of the POISE-2 Trial

Background: The relative contributions of intraoperative and postoperative hypotension to perioperative morbidity remain unclear. We determined the association between hypotension and a composite of 30-day myocardial infarction and death over three periods: (1) intraoperative, (2) remaining day of surgery, and (3) during the initial four postoperative days. Methods: This was a substudy of POISE-2, a 10,010-patient factorial-randomized trial of aspirin and clonidine for prevention of myocardial infarction. Clinically important hypotension was defined as systolic blood pressure less than 90 mmHg requiring treatment. Minutes of hypotension was the exposure variable intraoperatively and for the remaining day of surgery, whereas hypotension status was treated as binary variable for postoperative days 1 to 4. We estimated the average relative effect of hypotension across components of the composite using a distinct effect generalized estimating model, adjusting for hypotension during earlier periods. Results: Among 9,765 patients, 42% experienced hypotension, 590 (6.0%) had an infarction, and 116 (1.2%) died within 30 days of surgery. Intraoperatively, the estimated average relative effect across myocardial infarction and mortality was 1.08 (98.3% CI, 1.03, 1.12; P < 0.001) per 10-min increase in hypotension duration. For the remaining day of surgery, the odds ratio was 1.03 (98.3% CI, 1.01, 1.05; P < 0.001) per 10-min increase in hypotension duration. The average relative effect odds ratio was 2.83 (98.3% CI, 1.26, 6.35; P = 0.002) in patients with hypotension during the subsequent four days of hospitalization. Conclusions: Clinically important hypotension—a potentially modifiable exposure—was significantly associated with a composite of myocardial infarction and death during each of three perioperative periods, even after adjustment for previous hypotension.

Clonidine Does Not Reduce Pain or Opioid Consumption After Noncardiac Surgery.

BACKGROUND: Clonidine is an &agr;2-adrenoceptor agonist, which has analgesic properties. However, the analgesic efficacy of perioperative clonidine remains unclear. We, therefore, tested the hypothesis that clonidine reduces both pain scores and cumulative opioid consumption during the initial 72 hours after noncardiac surgery. METHODS: Six hundred twenty-four patients undergoing elective noncardiac surgery under general and spinal anesthesia were included in this substudy of the PeriOperative ISchemia Evaluation-2 trial. Patients were randomly assigned to 0.2 mg oral clonidine or placebo 2 to 4 hours before surgery, followed by 0.2 mg/d transdermal clonidine patch or placebo patch, which was maintained until 72 hours after surgery. Postoperative pain scores and opioid consumption were assessed for 72 hours after surgery. RESULTS: Clonidine had no effect on opioid consumption compared with placebo, with an estimated ratio of means of 0.98 (95% confidence interval, 0.70–1.38); P = 0.92. Median (Q1, Q3) opioid consumption was 63 (30, 154) mg morphine equivalents in the clonidine group, which was similar to 60 (30, 128) mg morphine equivalents in the placebo group. Furthermore, there was no significant effect on pain scores, with an estimated difference in means of 0.12 (95% confidence interval, −0.02 to 0.26); 11-point scale; P = 0.10. Mean pain scores per patient were 3.6 ± 1.8 for clonidine patients and 3.6 ± 1.8 for placebo patients. CONCLUSIONS: Clonidine does not reduce opioid consumption or pain scores in patients recovering from noncardiac surgery.

Degree of obesity is not associated with more than one intubation attempt: a large centre experience

Background: The role of obesity as a risk factor for difficult intubation remains controversial. We primarily assessed the association between body mass index (BMI) and difficult tracheal intubation. Methods: We analysed electronic records of more than 67 000 adults having elective non‐cardiac surgery requiring tracheal intubation at the Cleveland Clinic between 2011 and 2015. The association between BMI and difficult intubation, defined as more than one intubation attempt, was assessed using multivariable logistic regression adjusting for pre‐specified confounders. Results: Amongst 40 183 patients with BMI <30 kg m−2 and 27 519 with BMI ≥30 kg m−2, 9% required more than one intubation attempt. Increasing BMI up to 30 kg m−2 was significantly associated with increased odds of more than one intubation attempt [odds ratio (OR): 1.03; 97.5% confidence interval (CI): 1.02, 1.04] per unit increase in BMI, P < 0.001. However, the odds of difficult intubation remained unchanged once BMI exceeded 30 kg m−2 (P = 0.08). The results were similar when analysis was restricted to patients without history of airway abnormalities in whom intubation was attempted using a standard direct laryngoscope (OR: 1.03; 99.4% CI: 1.01, 1.04) per kg m−2 increase in BMI <30 kg m−2). Conclusions: Increasing BMI was associated with increasing odds of difficult intubation in the lean range. At higher BMI, the odds of difficult intubation remain elevated, but there is no additional increase in odds with further increase in BMI. Obese patients were thus harder to intubate than lean ones, but difficult intubation was no more likely in morbidly obese patients than in those who were only slightly obese.

Are perioperative therapeutic doses of statins associated with postoperative pain and opioid consumption after hip surgery under spinal anaesthesia

Background The anti-inflammatory effects of statins have been suggested to relieve postoperative pain. This retrospective study tested the association between the perioperative routine use of statins in therapeutic doses, and opioid requirements and pain scores, after hip replacement surgery. Methods With IRB approval, data was obtained for adult patients who had elective hip replacement surgery under spinal anaesthesia at Cleveland Clinic between 2005 and 2015. Patients were compared using a joint hypothesis framework. We used the inverse probability of treatment weighting method to control for observed confounding factors (a total of 26). Results We included 611 statin users and 780 non-statin users. Pain score during the initial 72 h after surgery was 0.07 higher (95% CI: -0.02, 0.17) in statin users (noninferiority test in both directions P<0.001). The estimated ratio of geometric means in the cumulative i.v. morphine equivalent opioid consumption was 1.01 (95% CI: 0.93, 1.10) for statin vs non-statin users (noninferiority test P=0.001 in the hypothesized direction and<0.001 in the other direction) during the initial 72 h after surgery. The statin and non-statin patients were deemed equivalent on postoperative opioid consumption and pain score. Conclusions This is the first large retrospective clinical study that investigates the effects of statin use on postoperative pain and opioid consumption. We observed no difference between statin users and non-users during the initial 72 h after hip surgery. Our findings do not support the routine use of statins as part of an analgesic regimen.

Association Between Intraoperative Low Blood Pressure and Development of Surgical Site Infection After Colorectal Surgery: A Retrospective Cohort Study

Objective: We tested the primary hypothesis that surgical site infections (SSIs) are more common in patients who had longer periods of intraoperative low blood pressure. Our secondary hypothesis was that hospitalization is prolonged in patients experiencing longer periods of critically low systolic blood pressure (SBP) and/or mean arterial pressure (MAP). Background: Hypotension compromises local tissue perfusion, thereby reducing tissue oxygenation. Hypotension might thus be expected to promote infection, but the extent to which low blood pressure contributes remains unclear. Methods: We considered patients who had colorectal surgery lasting at least 1 hour at the Cleveland Clinic between 2009 and 2013. The duration of hypotensive exposure and development of SSI was assessed with logistic regression; the association between hypotensive exposure and duration of hospitalization was assessed with Cox proportional hazard regression. Results: A total of 2521 patients were eligible for analysis. There was no adjusted association between SBP hypotension < 80 mm Hg and SSI, with an estimated odds ratio (95% confidence interval) of 0.97 (0.81, 1.17) per 5-minute increase in SBP hypotension (P = 0.54). There was also no adjusted association between MAP hypotension time and SSI, with estimated odds ratio of 0.97 (0.81, 1.17) for a 5-minute increase in MAP hypotension < 55 mm Hg time (P = 0.71). There was no association between duration of hypotension and time to discharge. Conclusions: Intraoperative hypotension does not seem to be a clinically important predictor of SSI after colorectal surgery, probably because the outcomes are overwhelmingly determined by other baseline and surgical factors—and perhaps postoperative hypotension.

Novel needle guide reduces time to perform ultrasound-guided femoral nerve catheter placement: A randomised controlled trial

BACKGROUND Ultrasound-guided nerve blocks have become the standard when performing regional nerve blocks in anaesthesia. Infiniti Plus (CIVCO Medical Solutions, Kalona, Iowa, USA) is a needle guide that has been recently developed to help clinicians in performing ultrasound-guided nerve blocks. OBJECTIVES We tested the hypothesis that femoral nerve catheter placement carried out with the Infiniti Plus needle guide will be quicker to perform than without the Infiniti Plus. Secondary aims were to assess whether the Infiniti Plus needle guide decreased the number of block attempts and also whether it improved needle visibility. DESIGN A randomised, controlled trial. SETTING Cleveland Clinic, Cleveland, Ohio, USA. PATIENTS We enrolled adult patients having elective total knee arthroplasty with a femoral nerve block and femoral nerve catheter. Patients, who were pregnant or those who had preexisting neuropathy involving the surgical limb, coagulopathy, infection at the block site or allergy to local anaesthetics were excluded. INTERVENTIONS Patients were randomised into two groups to receive the ultrasound-guided femoral nerve catheter placement with or without the Infiniti Plus needle guide. MAIN OUTCOME MEASURES The time taken to place the femoral nerve catheter, the number of attempts, the success rate and needle visibility were recorded. We used an overall &agr; of 0.05 for both the primary and secondary analyses; the secondary analyses were Bonferroni corrected to control for multiple comparisons. RESULT The median (interquartile range Q1 to Q3) time to perform the femoral nerve catheter placement was 118 (100 to 150) s with Infiniti Plus and 177 (130 to 236) s without Infiniti Plus. Infiniti Plus significantly reduced the time spent performing femoral nerve catheterisation, with estimated ratio of means [(95% confidence interval), P value] of 0.67 [(0.60 to 0.75), P < 0.001] with Infiniti Plus compared with no Infiniti Plus. However, Infiniti Plus had no effect on the odds of a successful femoral nerve catheter placement, number of attempts or percentage of perfect needle visibility. CONCLUSION We found that the use of Infiniti Plus decreased the median time to successfully place a femoral nerve catheter by 33% compared with not using Infiniti Plus. This difference may be more apparent to clinicians undertaking this procedure less often or by those in training as our team was very experienced, had been trained in the technique and was working in a hospital with a large caseload. TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT02080481.

Epidural compared with non-epidural analgesia and cardiopulmonary complications after colectomy: A retrospective cohort study of 20,880 patients using a national quality database

STUDY OBJECTIVE Epidural analgesia may be associated with fewer postoperative complications and is associated with improved survival after colon cancer resection. This study used the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) to assess any association between epidural analgesia (versus non-epidural) and complications after colectomy. DESIGN Retrospective cohort study. SETTING 603 hospitals in the United States reporting data to NSQIP. PATIENTS From 2014-15 data, 4176 patients undergoing colectomy with records indicating epidural analgesia were matched 1:4 via propensity scores to 16,704 patients without. INTERVENTIONS None (observational study). MEASUREMENTS Primarily, we assessed the association between epidural analgesia and a composite of cardiopulmonary complications using an average relative effect generalized estimating equations model. Secondary outcomes included neurologic, renal, and surgical complications and length of hospitalization. Sensitivity analyses repeated the analyses on a subgroup of only open colectomies. MAIN RESULTS We found no association between epidural analgesia and the primary outcome: average relative effect (95% CI) 0.87 (0.68, 1.11); P = 0.25. We found no significant associations with any secondary outcomes. In the 8005 open colectomies, however, there was a significant association between epidural analgesia and fewer cardiopulmonary complications (average relative effect odds ratio [95% CI] of 0.58 [0.35, 0.95]; P = 0.03) and shortened hospital stay (HR for time to discharge [98.75% CI] of 1.10 [1.02, 1.18]; P < 0.001). CONCLUSIONS We found no overall association between epidural analgesia and reduced complications after colectomy. In open colectomies, however, epidural analgesia was associated with fewer cardiopulmonary complications and shorter hospitalization. This may inform analgesic choice when planning open colectomy.

A Comparison of Global Longitudinal, Circumferential, and Radial Strain to Predict Outcomes after Cardiac Surgery

OBJECTIVE Myocardial strain measured by speckle-tracking echocardiography detects subtle regional and global left ventricular dysfunction. Myocardial strain is measured in the longitudinal, circumferential, and radial dimensions; however, it is unclear which dimension of strain is the best predictor of postoperative outcomes. DESIGN A secondary analysis of prospectively collected data from a clinical trial (NCT01187329). SETTING The cardiothoracic surgical operating rooms of an academic tertiary-care center. PARTICIPANTS Cardiothoracic surgery patients with aortic stenosis having aortic valve replacement (AVR) with or without coronary artery bypass grafting enrolled in a clinical trial. INTERVENTIONS Myocardial deformation analysis from standardized investigative transesophageal echocardiographic examinations performed after induction of anesthesia. MEASUREMENTS AND MAIN RESULTS The authors compared the ability of intraoperative global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) strain to predict adverse postoperative outcomes, including prolonged hospitalization and the need for pharmacologic hemodynamic support after cardiac surgery. The association of GLS, GCS, and GRS with prolonged hospitalization (>7 days) and the need for pharmacologic hemodynamic support, with epinephrine or norepinephrine after cardiopulmonary bypass, were assessed using separate multivariable logistic regression models with adjustment for multiple comparisons. Of 100 patients, 86 had acceptable measurements for GLS analysis, 73 for GCS, and 72 for GRS. Worse GLS was associated with prolonged hospitalization [odds ratio [OR] (98.3% confidence interval [CI]) of 1.21 (1.01-1.46) per-unit worsening in strain (p = 0.01, significance criterion <0.0167)] and the need for inotropic support with epinephrine [OR (99.2% CI) of 1.81 (1.10-2.97) per-unit worsening in strain (p = 0.002, significance criterion <0.0083)], but not norepinephrine. GCS and GRS were not associated with adverse outcomes. CONCLUSION GLS, but not GCS or GRS, predicts prolonged hospitalization and the requirement for inotropic support with epinephrine after AVR.