Adaptation and restructuring of an academic anesthesiology department during the COVID-19 pandemic in New York City: Challenges and lessons learned

The novel SARS-CoV-2 pandemic starting in 2019 profoundly changed the world, and thousands of residents of New York City were affected, leading to one of the most acute surges in regional hospital capacity. As the largest academic medical center in the Bronx, Montefiore Medical Center was immediately impacted, and the entire hospital was mobilized to address the needs of its community. In this article, we describe our experiences as a large academic anesthesiology department during this pandemic. Our goals were to maximize our staff's expertise, maintain our commitment to wellness and safety, and preserve the quality of patient care. Lessons learned include the importance of critical care training presence and leadership, the challenges of converting an ambulatory surgery center to an intensive care unit (ICU), and the management of effective communication. Lastly, we provide suggestions for institutions facing an acute surge, or subsequent waves of COVID-19, based on a single center's experiences.

Anesthesiology Training in the Time of COVID-19: Problems and Solutions

From March to June of 2020, Montefiore Medical Center faced one of the most acute surges in hospital admissions and critical illness ever experienced in the United States due to the severe acute respiratory syndrome coronavirus 2 pandemic. The pandemic had not yet spread to most of the country, and there was a relative deficit of knowledge regarding treatments, prognosis, and prevention of the virus, making this experience relatively unique and challenging. As part of a surge plan, our institution converted nonclinical spaces, such as conference rooms, to inpatient care settings and placed elective surgeries on hold to free up resources. A central deployment office suspended anesthesiology resident rotations and instead assigned them to intensive care settings based on need. For the Montefiore Medical Center Department of Anesthesiology, preserving its academic mission and commitment to Graduate Medical Education was essential. Adaptations included changing the residency rotation structure to biweekly, converting didactics online, ensuring adequate case numbers for graduating residents, actively pursuing wellness interventions, and prioritizing the safety of the residents caring for patients with coronavirus disease 2019 (COVID-19). In this brief report, the authors discuss solutions devised to maintain the quality of anesthesiology resident education and training as much as possible during the COVID-19 surge.

Assessment of Didactic Transesophageal Echocardiography Education During Anesthesia Residency

BACKGROUND

Transesophageal echocardiography can be a useful monitor during noncardiac surgery, in patients with comorbidities and/or undergoing procedures associated with substantial hemodynamic changes. The goal of this study was to investigate if transesophageal-echocardiography-related knowledge could be acquired during anesthesia residency.

METHODS

After institutional review board approval, a prospective observational study was performed in two anesthesiology residency programs. After a 41-week didactic transesophageal-echocardiography-education curriculum residents' exam scores were compared to baseline. The educators' examination was validated against the National Board of Echocardiography's Examination of Special Competence in Advanced Perioperative Transesophageal Echocardiography.

RESULTS

After the 41-week course, clinical anesthesia (CA)-3 exam scores increased 12% compared to baseline (P = .03), CA-2 scores increased 29% (P = .007), and CA-1 scores increased 25% (P = .002). Pearson correlation coefficient between the educators' exam score and the special competence exam percentile rank was 0.69 (P = .006). Pearson correlation coefficient between the educators' exam score and the special competence exam scaled score was 0.71 (P = .0045).

CONCLUSIONS

The 41-week course resulted in significant increases in exam scores in all 3 CA-classes. While didactic knowledge can be learned by anesthesiology residents during training, it requires significant time and effort. It is important to educate residents in echocardiography, to prepare them for board examinations and to care for the increasingly older and sicker patient population. Further work needs to be done to determine optimal methods to provide such education.

Measurement of resident fatigue using rapid number naming

OBJECTIVE

Sleep deprivation has a negative effect on neurocognitive performance. The King-Devick test (KDT), which tests speed and accuracy of number-reading, requires integrity of saccades, visual processing, and cognition. This study investigated effects of sleep deprivation in on-call residents using KDT.

METHODS

A prospective cohort study was conducted among 80 residents. KDT was performed at the beginning and end of an overnight call shift for the residents in the experimental group. A control group was tested at the beginning of 2 consecutive day shifts. Estimates of hours of sleep, Karolinska Sleepiness Scale (KSS)(1 = extremely alert, 9 = extremely sleepy), and time and accuracy of KDT were recorded.

RESULTS

42 residents were tested before and after overnight call shifts and 38 served as controls. Change in test time differed between the groups, with the experimental group performing 0.54(SD = 4.0) seconds slower after their night on call and the control group performing 2.32(SD = 3.0) seconds faster on the second day, p < 0.001. This difference was larger in surgical compared to medical residents.

CONCLUSIONS

Sleep deprivation was inversely correlated with neurocognitive performance as measured by KDT, with more effect on surgical than medical residents. Further research could investigate whether this test could help determine fatigue level and ability to continue working after a long shift.

Perioperative Efficiency vs. Quality of Care - Do We Always Have to Choose?

Introduction: ATTEMPTS to enforce optimization practices for operating room (OR) efficiency are often interpreted as a "pressure for production" which threatens patient safety. The aim of this study is to assess if and how improvements in OR efficiency affect patient safety and thus the quality of care. Methods: In an attempt to optimize OR efficiency, a new OR management approach "Integrated Practice Improvement Solutions" (IPIS) was developed at the Weiler Division of Montefiore Medical Center in 2011. IPIS is a flexible managerial system based on elements of multiple practice improvement methodologies incorporated into an open source framework. It was implemented in 2012. The data presented covers the period from 2012 through 2014 when the system was temporarily discontinued due to administrative restructuring. Data from 2011 was used as a baseline. The impact of IPIS on patient safety and quality of care was assessed based on quality improvement and patient safety (QIPS) Committee reports covering the same period of time. Results: IPIS implementation resulted in an increase in surgical workload by an average of 10.7%, an increase in OR and anesthesia revenues by 18.5% and 6.9%, respectively, and decreases in turnover time by 15% and overtime for the anesthesia staff by 26%. Based on QIPS reports, the total number of complications potentially attributable to "production pressure" was 0.25%, 0.2% and 0.16% in 2012, 2013 and 2014, respectively compared to 0.21% in 2011 (p = 0.56). Conclusions: Gradual implementation of a methodologically structured improvement in OR efficiency has no negative impact on patient safety and quality of care.

Intra-ventrolateral preoptic nucleus injection of γ-aminobutyric acid induces sedation in rats

The ventrolateral preoptic nucleus (VLPO) plays a critical role in regulating and maintaining sleep-awake cycle. It receives both excitatory and inhibitory inputs and regulates the activity of tuberomamillary nucleus and other monoaminergic nuclei, which in turn determines the alternation between wakefulness and non-rapid eye movement sleep. Although a previous study has shown that systematic administration of GABAergic anesthetic agents activated VLPO neurons, which is believed to be responsible for the sedative effects of these agents, it is unknown whether a direct administration of γ-Aminobutyric acid (GABA) into the VLPO can induce sedation. Here we report that rats that received intra-VLPO infusion of GABA demonstrated sustained reduction in locomotion, most significantly during the 10-40th min period after infusion. Conversely, rats that received intra-VLPO infusion of noradrenaline demonstrated a sustained increase in locomotion from 20(th) min after infusion. By contrast, no appreciable change was observed in rats that received intra-VLPO infusion of glycine. This result demonstrates that exogenous GABA may activate sleep-active neurons in the VLPO and promote sedation.

A prospective controlled study to determine the blood propofol concentration in anesthesiologists exposed to propofol vapor in the expired gases of patients receiving propofol-based intravenous sedation

STUDY OBJECTIVE

To determine the blood propofol concentration of anesthesiologists who were exposed to the expired gases of patients receiving propofol-based intravenous (IV) sedation.

DESIGN

Prospective controlled investigation and laboratory analysis.

SETTING

Operating room of a university hospital and an independent technical laboratory.

SUBJECTS

5 anesthesiologists who independently delivered propofol-based IV sedation to patients presenting for first trimester termination of pregnancy. In addition, a patient receiving propofol-based IV sedation was recruited as a positive control. A laboratory technician who never had previous exposure to propofol was recruited as a negative control.

INTERVENTIONS

Blood samples were obtained from each anesthesiologist before and after an 8-hour work period of anesthesia care of patients as described above. Blood samples were also obtained from the positive control, following propofol-based IV sedation, and the negative control.

MEASUREMENTS

An independent laboratory determined the blood propofol concentrations using a gas-liquid partition chromatograph and verified the results by repeated measurements in order to avoid a laboratory error. The gas-liquid partition chromatograph had an analytic capability that set the detection limit for propofol at 50 ng/mL.

MAIN RESULTS

None of the anesthesiologists had detectable blood propofol concentration in either the pre-exposure or post-exposure sample. The positive control and the negative control had detectable and non-detectable blood propofol concentration, respectively.

CONCLUSIONS

This experiment did not detect propofol in the blood of anesthesiologists who administered propofol-based IV sedation to patients.

Early postoperative cognitive dysfunction and postoperative delirium after anaesthesia with various hypnotics: study protocol for a randomised controlled trial--the PINOCCHIO trial

Background

Postoperative delirium can result in increased postoperative morbidity and mortality, major demand for postoperative care and higher hospital costs. Hypnotics serve to induce and maintain anaesthesia and to abolish patients' consciousness. Their persisting clinical action can delay postoperative cognitive recovery and favour postoperative delirium. Some evidence suggests that these unwanted effects vary according to each hypnotic's specific pharmacodynamic and pharmacokinetic characteristics and its interaction with the individual patient.

We designed this study to evaluate postoperative delirium rate after general anaesthesia with various hypnotics in patients undergoing surgical procedures other than cardiac or brain surgery. We also aimed to test whether delayed postoperative cognitive recovery increases the risk of postoperative delirium.

Methods/Design

After local ethics committee approval, enrolled patients will be randomly assigned to one of three treatment groups. In all patients anaesthesia will be induced with propofol and fentanyl, and maintained with the anaesthetics desflurane, or sevoflurane, or propofol and the analgesic opioid fentanyl.

The onset of postoperative delirium will be monitored with the Nursing Delirium Scale every three hours up to 72 hours post anaesthesia. Cognitive function will be evaluated with two cognitive test batteries (the Short Memory Orientation Memory Concentration Test and the Rancho Los Amigos Scale) preoperatively, at baseline, and postoperatively at 20, 40 and 60 min after extubation.

Statistical analysis will investigate differences in the hypnotics used to maintain anaesthesia and the odds ratios for postoperative delirium, the relation of early postoperative cognitive recovery and postoperative delirium rate. A subgroup analysis will be used to categorize patients according to demographic variables relevant to the risk of postoperative delirium (age, sex, body weight) and to the preoperative score index for delirium.

Discussion

The results of this comparative anaesthesiological trial should whether each the three hypnotics tested is related to a significantly different postoperative delirium rate. This information could ultimately allow us to select the most appropriate hypnotic to maintain anaesthesia for specific subgroups of patients and especially for those at high risk of postoperative delirium.

Registered at Trial.gov Number

ClinicalTrials.gov: NCT00507195

Low tidal volume and high positive end-expiratory pressure mechanical ventilation results in increased inflammation and ventilator-associated lung injury in normal lungs

BACKGROUND

Protective mechanical ventilation with low tidal volume (Vt) and low plateau pressure reduces mortality and decreases the length of mechanical ventilation in patients with acute respiratory distress syndrome. Mechanical ventilation that will protect normal lungs during major surgical procedures of long duration may improve postoperative outcomes. We performed an animal study comparing 3 ventilation strategies used in the operating room in normal lungs. We compared the effects on pulmonary mechanics, inflammatory mediators, and lung tissue injury.

METHODS

Female pigs were randomized into 3 groups. Group H-Vt/3 (n = 6) was ventilated with a Vt of 15 mL/kg predicted body weight (PBW)/positive end-expiratory pressure (PEEP) of 3 cm H(2)O, group L-Vt/3 (n = 6) with a Vt of 6 mL/kg PBW/PEEP of 3 cm H(2)O, and group L-Vt/10 (n = 6) with a Vt of 6 mL/kg PBW/PEEP of 10 cm H(2)O, for 8 hours. Hemodynamics, airway mechanics, arterial blood gases, and inflammatory markers were monitored. Bronchoalveolar lavage (BAL) was analyzed for inflammatory markers and protein concentration. The right lower lobe was assayed for mRNA of specific cytokines. The right lower lobe and right upper lobe were evaluated histologically.

RESULTS

In contrast to groups H-Vt/3 and L-Vt/3, group L-Vt/10 exhibited a 6-fold increase in inflammatory mediators in BAL (P < 0.001). Cytokines in BAL were similar in groups H-Vt/3 and L-Vt/3. Group H-Vt/3 had a significantly lower lung injury score than groups L-Vt/3 and L-Vt/10.

CONCLUSION

Comparing intraoperative strategies, ventilation with high PEEP resulted in increased production of inflammatory markers. Low PEEP resulted in lower levels of inflammatory markers. High Vt/low PEEP resulted in less histologic lung injury.

Teaching and evaluating group competency in systems-based practice in anesthesiology

BACKGROUND

Teaching and assessment of the systems-based practice competency has been problematic in hospital-based specialties such as anesthesiology. We developed a method to teach systems-based practice with collaborative team projects. The outcome was assessed with a tool that focused on group attributes.

METHODS

Resident teams chose projects that focused on the health care system. Projects included economic analyses, safety initiatives, process analyses, and policy revisions. Projects were presented by groups in poster discussion sessions. The educational program was evaluated using five criteria: implementation, awareness and acceptance in the organization, utility, sustainability, and diffusion to other programs.

RESULTS

The plan was implemented in 2005 and remains a required part of the resident curriculum. Key hospital and medical school leaders in our health care system participated in projects. Interdisciplinary collaboration occurred with multiple clinical departments. Nine projects performed economic analysis, 5 involved safety initiatives, 10 performed process analysis and recommended change, and 4 affected policy change in the institution. The program has been sustainable and has been effective in creating multidisciplinary institutional policy.

CONCLUSIONS

We developed an innovative method to teach systems-based practice through a team-based project initiative. The projects appear to have had a positive impact on our health care organization. Our assessment tool for the project evaluated team, rather than individual, performance, which is crucial in this competency.

Nanomolar propofol stimulates glutamate transmission to dopamine neurons: a possible mechanism of abuse potential?

Anesthesiologists among physicians are on the top of the drug abuse list, and the mechanism is unclear. Recent studies suggest occupation-related second-hand exposure to i.v. drugs, including propofol, may play a role. Growing evidence indicates that propofol is one of the choices of drugs being abused. In this study, we show that propofol at minute concentrations increases glutamatergic excitatory synaptic transmission and discharges of dopamine neurons in the ventral tegmental area (VTA). We found that acute application of propofol (0.1-10 nM) to the VTA in midbrain slices of rats increased the frequency but not the amplitude of spontaneous excitatory postsynaptic currents (EPSCs) mediated by alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors. We observed that propofol increased the amplitude but decreased the paired-pulse ratio of EPSCs evoked by stimulation in the absence and the presence of gabazine (SR 95531), a GABA(A) receptor antagonist. Moreover, the propofol-induced facilitation of EPSCs was mimicked by 6-phenyl-4-azabicyclo[5.4.0]undeca-7,9,11-triene-9,10-diol (SKF38393), an agonist of dopamine D(1) receptor, and by 1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)piperazine dihydrochloride (GBR 12935), a dopamine reuptake inhibitor, but blocked by (+/-)-7-bromo-8-hydroxy-3-methyl-1-phenyl-2,3,4, 5-tetrahydro-1H-3-benzazepine hydrochloride (SKF83566), a D(1) antagonist, or by depleting dopamine stores with reserpine. Finally, 1 nM propofol increased the spontaneous discharge rate of dopamine neurons. These findings suggest that propofol at minute concentrations enhances presynaptic D(1) receptor-mediated facilitation of glutamatergic synaptic transmission and the excitability of VTA dopamine neurons, probably by increasing extracellular dopamine levels. These changes in synaptic plasticity in the VTA, an addiction-related brain area might contribute to the development of propofol abuse and the increased susceptibility to addiction of other drugs.

Labetalol facilitates GABAergic transmission to rat periaqueductal gray neurons via antagonizing beta1-adrenergic receptors--a possible mechanism underlying labetalol-induced analgesia

Labetalol, a combined alpha1, beta1, and beta2 adrenoceptor-blocking drug, has been shown to have analgesic properties in vivo. To determine the underlying mechanisms, we examined its effects on GABAA receptor-mediated spontaneous inhibitory postsynaptic currents (sIPSCs) and spontaneous firings of rat ventrolateral periaqueductal gray (PAG) neurons, either mechanically dissociated, or in acute brain slices. These PAG neurons mediate opioid-mediated analgesia and pain transmission and are under tonic control of GABAergic interneurons. An increase in GABAergic transmission to these neurons yields an inhibitory hyperpolarized state and may interrupt pain signal transmission. Using patch clamp techniques, we found that labetalol reversibly increases the frequency of sIPSCs without changing their mean amplitude. This indicates that labetalol enhances GABAergic synaptic transmission by a presynaptic mechanism. Metoprolol, a specific beta1-adrenoceptor antagonist, also reversibly enhanced sIPSC frequency. In the presence of metoprolol, labetalol-induced increase in sIPSC frequency was significantly attenuated or even abolished. These results suggest that labetalol shares the same pathway as metoprolol in enhancing GABAergic transmission via an inhibition of presynaptic beta1-adrenoceptors. We further showed that labetalol reversibly reduced the firing rate of PAG neurons. This reduction was significantly attenuated in the presence of bicuculline, a selective antagonist of GABAA receptors. These data indicate that labetalol-induced inhibition of PAG cell firing is attributable to its potentiation of GABAergic transmission. Based on these data, we postulate that labetalol-induced analgesia is at least in part ascribed to its antagonistic effects on presynaptic beta1-adrenoceptors.

Sevoflurane Provides Earlier Tracheal Extubation and Assessment of Cognitive Recovery Than Isoflurane in Patients Undergoing Off-Pump Coronary Artery Bypass Surgery

OBJECTIVE

To determine whether sevoflurane, because of its lower blood/gas partition coefficient, compared with isoflurane as the primary anesthetic agent, allows earlier tracheal extubation and assessment of cognitive function after off-pump coronary artery bypass (OPCAB) surgery.

DESIGN

Prospectively, patients were randomly assigned to receive sevoflurane or isoflurane as their primary anesthetic. Intraoperative opioids were limited to 5 microg/kg of fentanyl.

SETTING

Two university hospitals with active cardiac surgery programs.

PARTICIPANTS

One hundred one OPCAB surgery patients who met inclusionary and exclusionary criteria participated with institutional review board approval.

INTERVENTIONS

Mini-Mental Status Examination, Memory Recall Test, and Observer Assessment of Anxiety and Sedation scales were administered preoperatively, postextubation, at 90 minutes, and between 12 to 24 hours. Pain scores were obtained every 15 minutes after extubation for 90 minutes.

MEASUREMENTS AND MAIN RESULTS

Sevoflurane patients were extubated earlier than isoflurane patients (Sevo, 176 +/- 217 minutes and Iso, 257 +/- 279 min, p = 0.02). Although both agents produced similar postanesthetic cognitive profiles, cognitive testing occurred approximately 90 minutes earlier in the sevoflurane group. Verbal rating scale for pain scores >5 were more frequent for sevoflurane than isoflurane patients (p = 0.03).

CONCLUSIONS

Both sevoflurane and isoflurane may be safely used as maintenance agents in OPCAB. Sevoflurane has the advantage of allowing earlier extubation and evaluation of cognitive and neurologic function after OPCAB.

Distraction with a hand-held video game reduces pediatric preoperative anxiety

BACKGROUND

Video games have received widespread application in health care for distraction and behavior modification therapy. Studies on the effect of cognitive distraction during the preoperative period are lacking. We evaluated the efficacy of an interactive distraction, a hand-held video game (VG) in reducing preoperative anxiety in children.

METHODS

In a randomized, prospective study of 112 children aged 4-12 years undergoing outpatient surgery, anxiety was assessed after admission and again at mask induction of anesthesia, using the modified Yale Preoperative Anxiety Scale (mYPAS). Postoperative behavior changes were assessed with the Posthospital Behavior Questionnaire (PHBQ). Patients were randomly assigned to three groups: parent presence (PP), PP+a hand-held VG, and PP+0.5 mg.kg-1 oral midazolam (M) given>20 min prior to entering the operating room.

RESULTS

There was a statistically significant increase in anxiety (P<0.01) in groups M and PP at induction of anesthesia compared with baseline, but not in VG group. VG patients demonstrated a decrease in anxiety from baseline (median change in mYPAS -3), the difference compared with PP (+11.8) was significant (P=0.04). The change in anxiety in the M group (+7.3) was not statistically different from other groups. Sixty-three percent of patients in VG group had no change or decrease in anxiety after treatment, compared with 26% in M group and 28% in PP group (P=0.01). There was no difference in anxiety changes between female and male patients.

CONCLUSIONS

A hand-held VG can be offered to most children as a low cost, easy to implement, portable, and effective method to reduce anxiety in the preoperative area and during induction of anesthesia. Distraction in a pleasurable and familiar activity provides anxiety relief, probably through cognitive and motor absorption.

Successful intraoperative use of recombinant tissue plasminogen activator during liver transplantation complicated by massive intracardiac/pulmonary thrombosis

During orthotopic liver transplantation a patient received epsilon-aminocaproic acid and clotting factors. Shortly after hepatic artery clamping the patient developed a massive intracardiac/intravascular thrombosis that resulted in cardiac arrest. After diagnosis by transesophageal echocardiography, the patient was treated with recombinant tissue plasminogen activator through a central venous catheter advanced into the right atrium. After treatment with recombinant tissue plasminogen activator, the patient's hemodynamic status improved, permitting the liver transplant to be completed. The patient was ultimately discharged to home. We report the successful intraoperative resuscitation of a patient with acute intracardiac/intravascular thrombosis during an orthotopic liver transplantation using thrombolytic therapy.

Sex-based differences in serum cardiac troponin I, a specific marker for myocardial injury, after cardiac surgery

BACKGROUND

Prevalence and causes of sex-based differences in morbidity and mortality secondary to cardiovascular disease remain controversial. Cardiac troponin I (cTnI) is a sensitive and specific marker for myocardial injury. Serial cTnI measurements have been used to identify perioperative myocardial cell injury.

OBJECTIVE

To determine whether sex influences the extent of myocardial injury during cardiac surgery, we measured perioperative cTnI in male and female patients.

DESIGN

A total of 17 male and 17 female patients were prospectively studied in an age- and case-matched manner. Arterial cTnI were obtained preinduction, 30 mins after the application of the aortic cross-clamp, at arrival to the intensive care unit, and on postoperative day 1.

SETTING

Tertiary cardiac surgery center at a major teaching hospital.

RESULTS

There was no difference between men and women in body mass index (kg/m2), duration of cardiopulmonary bypass, and aortic cross-clamp times. Preoperative cTnI measurements were similar in men (0.24 +/- 0.15 ng/mL) and women (0.25 +/- 0.13 ng/mL, mean +/- sem). The maximum serum cTnI occurred on postoperative day 1 in all patients, and it was 3-fold higher in men (18.5 +/- 5.7 ng/mL) compared with women (6.4 +/- 1.0 ng/mL).

CONCLUSIONS

Men had markedly higher serum cTnI compared with women, although they were case matched with respect to age and cardiac risk factors. Our results may suggest there may be sex-related differences in the myocardial response to ischemia and reperfusion injury or intrinsic differences between the male and female myocardium.

Photosystem II fluorescence quenching in the cyanobacterium Synechocystis PCC 6803: involvement of two different mechanisms

The structural changes associated to non-photochemical quenching in cyanobacteria is still a matter of discussion. The role of phycobilisome and/or photosystem mobility in this mechanism is a point of interest to be elucidated. Changes in photosystem II fluorescence induced by different quality of illumination (state transitions) or by strong light were characterized at different temperatures in wild-type and mutant cells, that lacked polyunsaturated fatty acids, of the cyanobacterium Synechocystis PCC 6803. The amplitude and the rate of state transitions decreased by lowering temperature in both strains. Our results support the hypothesis that a movement of membrane complexes and/or changes in the oligomerization state of these complexes are involved in the mechanism of state transitions. The quenching induced by strong blue light which was not associated to D1 damage and photoinhibition, did not depend on temperature or on the membrane state. Thus, the mechanism involved in the formation of this type of quenching seems to be unrelated to the movement of membrane complexes. Our results strongly support the idea that the mechanism involved in the fluorescence quenching induced by light 2 is different from that involved in strong blue light induced quenching.

Incidence of atrial fibrillation after mild or moderate hypothermic cardiopulmonary bypass

OBJECTIVES

Atrial fibrillation remains a significant source of morbidity after coronary artery bypass grafting (CABG). Whether cardiopulmonary bypass (CPB) temperature influences the occurrence of postoperative atrial fibrillation in CABG patients has not been specifically examined. In the present study, we reviewed postoperative data from patients who were prospectively randomized to mild or moderate hypothermic CPB for elective CABG to determine the incidence of postoperative atrial fibrillation.

DESIGN

Randomized, single center, observational study.

SETTING

Tertiary university medical center.

PATIENTS

Adults undergoing elective CABG surgery.

INTERVENTIONS

Enrolled patients were prospectively randomized to mild (34 degrees C [93.2 degrees F]) or moderate (28 degrees C [82.4 degrees F]) hypothermic CPB.

MEASUREMENTS AND MAIN RESULTS

The incidence of postoperative atrial fibrillation was determined by review of ICU and hospital records. There was a significantly higher incidence of atrial fibrillation in the moderate compared with the mild hypothermic CPB group. Patients who had postoperative atrial fibrillation were significantly older than those without atrial fibrillation. Furthermore, a significant increase in the relative risk of developing postoperative atrial fibrillation was found for both age and CPB temperature.

CONCLUSIONS

Our results indicate that the temperature of systemic cooling during CPB is an important factor in the development of atrial fibrillation after CABG surgery. In addition, this study confirms that increasing age is a significant determinant of postoperative atrial fibrillation.

DeltapH-dependent photosystem II fluorescence quenching induced by saturating, multiturnover pulses in red algae

We have previously shown that in the red alga Rhodella violacea, exposure to continuous low intensities of light 2 (green light) or near-saturating intensities of white light induces a DeltapH-dependent PSII fluorescence quenching. In this article we further characterize this fluorescence quenching by using white, saturating, multiturnover pulses. Even though the pulses are necessary to induce the DeltapH and the quenching, the development of the latter occurred in darkness and required several tens of seconds. In darkness or in the light in the presence of 2, 5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, the dissipation of the quenching was very slow (more than 15 min) due to a low consumption of the DeltapH, which corresponds to an inactive ATP synthase. In contrast, under far-red illumination or in the presence of 3-(3,4-dichlorophenyl)-1,1'-dimethylurea (only in light), the fluorescence quenching relaxed in a few seconds. The presence of N, N'-dicyclohexyl carbodiimide hindered this relaxation. We propose that the quenching relaxation is related to the consumption of DeltapH by ATP synthase, which remains active under conditions favoring pseudolinear and cyclic electron transfer.

Paediatric cardiac anaesthesia in a developing country. Guatemala Heart Team

During the week of October 15-24, 1995 a team of 65 medical, anaesthesiology, surgical, nursing and paramedical personnel travelled to Guatemala City, Guatemala to perform cardiac surgery on children with complex congenital and acquired valvular heart disease. During this mission 42 patients had their lesions surgically repaired. Cardiopulmonary bypass was required in 36 cases. There were no anaesthetic or surgical deaths. All six patients who did not require cardiopulmonary bypass were extubated in the operating room. Of the patients who required cardiopulmonary bypass, 23 were extubated in the operating room (64%). There was no intraoperative anaesthetic morbidity nor postoperative respiratory complications. No patients was reintubated after planned extubation. Cardiac surgery in paediatric age patients can safely be performed in developing countries if close attention is paid to proper patient selection and one maintains the standards of care practised in developed countries.

Sympathetic response during cardiopulmonary bypass: mild versus moderate hypothermia

OBJECTIVE

To determine the sympathetic response during cardiopulmonary bypass at mild (34 degrees C) and moderate (28 degrees C) hypothermia.

DESIGN

A randomized study.

SETTING

Tertiary university hospital.

PATIENTS

Adults undergoing elective coronary artery bypass graft surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma norepinephrine, epinephrine, and neuropeptide Y concentrations were measured. Moderate, but not mild, hypothermic cardiopulmonary bypass evoked a significant sympathetic response with increases in plasma norepinephrine and neuropeptide Y concentrations. A significantly higher incidence of postoperative atrial fibrillation was also observed in the moderate hypothermic compared with the mild hypothermic group.

CONCLUSIONS

Our results indicate that the degree of hypothermia significantly influences the sympathetic response during cardiopulmonary bypass. The higher incidence of postoperative atrial fibrillation in the moderate hypothermic group suggests that the enhanced sympathetic response might be one contributing factor in the development of atrial fibrillation.

Cerebral dysfunction after coronary artery bypass grafting done with mild or moderate hypothermia

OBJECTIVE

Ninety-nine patients undergoing elective coronary artery bypass grafting were enrolled in a prospective, randomized study to evaluate the incidence of cerebral dysfunction after "mild" or "moderate" hypothermia during cardiopulmonary bypass.

METHODS

Patients were evaluated before and after operation before hospital discharge and in some cases at follow-up at least 6 weeks later with a complete neurologic examination (85 patients) and a battery of standard neuropsychometric tests (86 patients).

RESULTS

Postoperative changes detected by neurologic examination consisted of the appearance of new primitive reflexes in both groups. No statistically significant differences in incidence were found. The neuropsychometric performances of the two groups were statistically similar by either event-rate or group-rate analysis.

CONCLUSIONS

There is no detectable difference in postoperative cerebral dysfunction in patients undergoing coronary artery bypass grafting who are supported by cardiopulmonary bypass with either mild or moderate hypothermia.

State transitions or delta pH-dependent quenching of photosystem II fluorescence in red algae

Fluorescence changes attributed to state transitions have been shown to exist in phycobilisome-containing organisms. Contradictory conclusions have been derived from studies about the mechanism of state transitions carried out either in cyanobacteria or in red algae. In this paper, fluorescence changes induced by light 1 and light 2 are reinvestigated in a unicellular red alga, Rhodella violacea, by performing 77 K fluorescence spectra and fluorescence yield measurements at room temperature in the presence of uncouplers and inhibitors of the electron transfer. We show that transfer of light 1-adapted cells to light 2 (green light) induces a large quenching of photosystem II which is suppressed by subsequent incubation in light 1 (far-red or blue light). The level of the photosystem I-related fluorescence does not change during these transfers. We demonstrate that the large quenching of photosystem II induced by low intensities of green light is completely suppressed by addition of NH4Cl, an uncoupler that inhibits ATP synthesis by canceling the delta pH across the membrane. DCCD, which is an inhibitor of the ATPase that swells the delta pH, maintains the quenched state even under light 1 illumination. The opposite effects of DCMU and DBMIB on state transitions are demonstrated to be due to a suppression (by DCMU) or maintenance (by DBMIB) of the delta pH and not to change in the redox state of the plastoquinone. We conclude that, in R. violacea, the fluorescence change commonly associated with state 2 transition is in fact a delta pH-dependent quenching. This type of quenching has always been associated with near-saturating light intensities. Here, we show that very low intensities of a light that activates only the photosystem II induce a delta pH across the membrane that is not dissipated since the ATPase is not activated. The delta pH is dissipated only under conditions in which the photosystem I turns, confirming that the thioredoxin must be reduced to activate the ATPase. We suggest that the fluorescence changes, induced by various light conditions, in cyanobacteria and red algae could be associated with different phenomena.

Jugular venous bulb oxyhemoglobin saturation during cardiac surgery: accuracy and reliability using a continuous monitor

Previous studies have demonstrated the feasibility of continuously monitoring jugular venous oxygen saturation (SjO2) with a fiberoptic catheter during hypothermic cardiopulmonary bypass (CPB). In the present study, with patients maintained at either moderate (28 degrees C) or mild (32-34 degrees C) hypothermia during CPB, SjO2 values obtained from a fiberoptic catheter were compared to intermittent samples analyzed by a co-oximeter. Twenty patients scheduled for elective coronary artery or valvular surgery had a 5.5 Fr Opticath catheter inserted into the left internal jugular bulb after induction of general anesthesia. The catheter was calibrated in vitro and in vivo according to the manufacturer's specifications. Catheter and co-oximetry SjO2 values obtained at four time points--1) pre-CPB, 2) target CPB temperature, 3) mid-rewarming, and 4) post-CPB--were compared using linear regression, Bland-Altman analysis, and Shrout-Fleiss interclass correlation coefficient analysis. These statistical methods revealed poor correlation between the catheter and co-oximetry SjO2 values: r = 0.44 by linear regression and 0.32 by interclass correlation coefficient analysis, and was unacceptably discrepant by Bland-Altman analysis. Oxyhemoglobin saturation values obtained continuously from a jugular venous bulb fiberoptic catheter during CPB may not accurately reflect true oxyhemoglobin saturation, and caution is warranted when interpreting SjO2 values obtained from a fiberoptic catheter during CPB.

Safety of repeat aprotinin administration for LVAD recipients undergoing cardiac transplantation

BACKGROUND

Anecdotal reports of allergic and anaphylactic reactions after aprotinin therapy have raised concern that its repeat use may be associated with substantial morbidity.

METHODS

To address this concern, we reviewed our experience with all patients who underwent implantation of a left ventricular assist device and subsequent cardiac transplantation with perioperative use of aprotinin.

RESULTS

Twenty-three patients received full-dose aprotinin during left ventricular assist device implantation and subsequent cardiac transplantation. All patients tolerated primary exposure to aprotinin without complication. One episode of anaphylaxis after secondary exposure was treated with rapid institution of cardiopulmonary bypass. Although renal dysfunction was observed shortly after cardiac transplantation in 30.4% of patients, the effect was transient and occurred in the presence of cyclosporine. The one perioperative death after secondary exposure was unrelated to bleeding complications. No clinically evident thromboembolic events were documented.

CONCLUSIONS

Primary and secondary exposure to aprotinin during operation with cardiopulmonary bypass is associated with limited intraoperative blood use, a low incidence of transient renal dysfunction and anaphylaxis, a rare need of reoperation for bleeding, and no clinical thromboembolic events.

Cerebral dysfunction after cardiac operations in elderly patients

BACKGROUND

Cerebral injury remains a significant complication of cardiac operations. We determined the incidence of cerebral dysfunction in a population of elderly patients undergoing open chamber cardiac operations (group 1) as compared with a younger population (group 2) and an age-matched group of elderly patients undergoing major noncardiac operations (group 3).

METHODS

Sixty-eight patients (55 for open chamber cardiac operations and 13 for noncardiac operations) were prospectively studied. Patients were evaluated preoperatively and postoperatively before hospital discharge using a complete neurologic examination and a battery of standard neuropsychometric tests, and at surgical follow-up with neuropsychometric tests only.

RESULTS

Postoperative changes detected by neurologic examination consisted of the appearance of new primitive reflexes in all groups. No statistically significant differences in incidence were found. The neuropsychometric performance of group 1 patients was statistically different from that of patients in groups 2 and 3 only in the early follow-up period.

CONCLUSIONS

Elderly patients having open chamber cardiac operations exhibit significantly more cerebral dysfunction in the early postoperative period than those undergoing major noncardiac operations and younger patients after open chamber procedures. These changes do not persist into the late follow-up period.

The reliability of quantitative electroencephalography as an indicator of cerebral ischemia

The electroencephalogram (EEG) has been used to detect episodes of cerebral ischemia during various surgical procedures. Recently, computerized systems for recording and interpreting the quantitative EEG (QEEG) have been used by anesthesiologists because of their ease of application, clarity of display, and reported ability to identify ischemic EEG changes. However, the extent to which automated techniques of QEEG interpretation reliably differentiate cerebral ischemia from the confounding effects of anesthetics and other sources of "artifact" is not completely established. In this study, EEGs were recorded before and after defibrillator testing in patients undergoing implantable cardioverter defibrillator (ICD) placement and during analogous time periods in control patients undergoing abdominal surgery. EEGs were subjected to standard visual inspection by an experienced electroencephalographer and QEEG analysis with a commercially available system was used for automated EEG interpretation in order to evaluate the reliability of this quantitative technique. The CIMON technique identified episodes which met previously defined criteria for QEEG cerebral dysfunction and ischemic pattern in both groups, despite the presumed absence of cerebral ischemia in the control patients. Since there was no evidence of cerebral ischemia in the raw EEGs of either the ICD patients or the controls, these QEEG changes were not confirmed by conventional techniques of EEG interpretation. Our results suggest that caution is warranted when using automated systems for intraoperative interpretation of EEG.

Implantable cardioverter-defibrillator. Evaluation of clinical neurologic outcome and electroencephalographic changes during implantation

During placement of implantable cardioverter-defibrillators, ventricular arrhythmias are induced to test the function of the devices. Although cerebral hypoperfusion and ischemic electroencephalographic changes occur in patients while implantable cardioverter-defibrillators are being tested, no investigation has assessed neurologic outcome in these patients. Nine patients having either implantation or change of an implantable cardioverter-defibrillator underwent neurologic examination and neuropsychometric tests before and after the operation. After induction of general anesthesia and insertion of implantable cardioverter-defibrillator leads (when needed), ventricular fibrillation, ventricular flutter, or ventricular tachycardia, was induced by means of programmed electrical stimulation. Implantable cardioverter-defibrillator testing continued until satisfactory lead placement was confirmed. The intraoperative electroencephalographic recording was analyzed for evidence of ischemic change. In all, an electroencephalogram was recorded during 50 periods of circulatory arrest. Mean duration of the arrest periods was 13.6 seconds. By means of conventional visual inspection of the raw electroencephalogram, high-amplitude rhythmic delta or theta, voltage attenuation, or loss of fast frequency activity was observed in 30 of the arrests. By means of an automated technique of electroencephalographic interpretation based on power spectral analysis, electroencephalographic changes were correctly identified in 26 of the arrests. The incidence of these electroencephalographic changes was dependent on the arrest duration. The mean interval from arrest onset to electroencephalographic change was 7.5 seconds (standard deviation +/- 1.8 seconds). In patients with electroencephalographic changes during multiple arrests, no downward trend in this interval was detected in later arrests and no evidence of persistent ischemic change was observed in electroencephalograms recorded after the conclusion of implantable cardioverter-defibrillator testing. Postoperative neurologic and neuropsychometric testing was completed in eight patients, none of whom exhibited a new neurologic deficit, exacerbation of a preexisting neurologic condition, or significant deterioration in neuropsychometric performance. We conclude that the brief arrest of cerebral circulation induced during insertion of an implantable cardioverter-defibrillator is not associated with permanent neurologic injury.

Noncardiac surgery in heart transplant recipients in the cyclosporine era

As survival and quality of life continue to improve for cardiac transplant recipients, there is an ever-increasing possibility that these patients will present for elective and/or emergency surgery outside of a transplantation center. Cyclosporine therapy has been a major factor in extending homograft survival, but recent studies have suggested that cyclosporine administration increases the duration of action of some anesthetics. The authors evaluated the influence on anesthetic management of cardiac transplantation and chronic cyclosporine therapy in a retrospective review of all postcardiac transplant patients who presented for noncardiac surgery at the study institution. The data suggest that a number of commonly used anesthetic techniques can be administered safely to these patients when no evidence of graft rejection is present. No clinically significant prolongation of anesthetic effect was encountered following the doses of anesthetics described.

Influence of temperature on in vitro metabolism of esmolol

Esmolol has been used to improve hemodynamic stability during sternotomy and aortic manipulation for coronary artery bypass graft surgery. In order to investigate the alterations of esmolol metabolism by hypothermic cardiopulmonary bypass (CPB), the effect of temperature on the metabolism of esmolol in vitro was determined. Samples of human whole blood were combined with esmolol solution (50 micrograms/mL in 0.9 mol/L NaCl) and incubated at 4 degrees C, 15 degrees C, 25 degrees C, and 37 degrees C. Aliquots were sampled at 1, 5, 10, 15, 30, 60, and 120 minutes; esmolol concentration was determined using high-pressure liquid chromatography. There was a temperature-dependent decrease in the degradation of esmolol. The half-life for esmolol in human blood was 19.6 +/- 3.8 minutes at 37 degrees C, 47 +/- 10.1 minutes at 25 degrees C, 152 +/- 46.6 minutes at 15 degrees C, and 226.7 +/- 60.1 minutes at 4 degrees C. This study clearly shows marked reduction of esmolol metabolism with hypothermia possibly leading to persistent beta-adrenergic blockade following the discontinuation of CPB. Persistent beta-blockade may provide additional protection to the ischemic myocardium during hypothermic arrest and/or result in difficulty in weaning from CPB.