Increasing comparability among coral bleaching experiments.

Coral bleaching is the single largest global threat to coral reefs worldwide. Integrating the diverse body of work on coral bleaching is critical to understanding and combating this global problem. Yet investigating the drivers, patterns, and processes of coral bleaching poses a major challenge. A recent review of published experiments revealed a wide range of experimental variables used across studies. Such a wide range of approaches enhances discovery, but without full transparency in the experimental and analytical methods used, can also make comparisons among studies challenging. To increase comparability but not stifle innovation, we propose a common framework for coral bleaching experiments that includes consideration of coral provenance, experimental conditions, and husbandry. For example, reporting the number of genets used, collection site conditions, the experimental temperature offset(s) from the maximum monthly mean (MMM) of the collection site, experimental light conditions, flow, and the feeding regime will greatly facilitate comparability across studies. Similarly, quantifying common response variables of endosymbiont (Symbiodiniaceae) and holobiont phenotypes (i.e., color, chlorophyll, endosymbiont cell density, mortality, and skeletal growth) could further facilitate cross-study comparisons. While no single bleaching experiment can provide the data necessary to determine global coral responses of all corals to current and future ocean warming, linking studies through a common framework as outlined here, would help increase comparability among experiments, facilitate synthetic insights into the causes and underlying mechanisms of coral bleaching, and reveal unique bleaching responses among genets, species, and regions. Such a collaborative framework that fosters transparency in methods used would strengthen comparisons among studies that can help inform coral reef management and facilitate conservation strategies to mitigate coral bleaching worldwide.

The frequency of perioperative vision loss.

UNLABELLED: The frequency of perioperative vision loss, especially for spinal surgery, has been increasing recently. We undertook a retrospective study to determine the frequency of this outcome in a large surgical population receiving general or central neuraxis regional anesthesia for noncardiac procedures from 1986 to 1998. Specific criteria were used to separate cases in which the surgical procedure likely directly contributed to the vision loss. Vision loss was present if any part of the visual field was affected. Initial database screening found 405 cases of new-onset vision loss or visual changes in 410,189 patients who underwent 501,342 anesthetics and who survived at least 30 days after their final procedures. Two hundred sixteen of these patients regained full vision or acuity within 30 days. Of the 189 patients who developed vision deficits for longer than 30 days, 185 underwent ophthalmologic or neurologic procedures in which ocular or cerebral tissues were surgically damaged or resected. The remaining 4 patients (1 per 125,234 overall; 0.0008%) developed prolonged vision loss without direct surgical trauma to optic or cerebral tissues. In this large study population of noncardiac surgical patients, including those who underwent spinal surgical procedures, the frequency of perioperative vision loss persisting for longer than 30 days was very small. IMPLICATIONS: Vision loss and blindness after surgery and anesthesia is a very rare event. In this study, only one per 125,234 patients undergoing noncardiac surgery developed vision loss persisting for longer than 30 days.

Perianaesthetic risks and outcomes of abdominal surgery for metastatic carcinoid tumours.

Patients with metastatic carcinoid tumours often undergo surgical procedures to reduce the tumour burden and associated debilitating symptoms. These procedures and anaesthesia can precipitate a life-threatening carcinoid crisis. To assess perioperative outcomes, we studied retrospectively the medical records of adult patients from 1983 to 1996 who underwent abdominal surgery for metastatic carcinoid tumours. Preoperative risk factors, intraoperative complications and complications occurring in the 30 days after surgery were recorded. Perioperative complications or death occurred in 15 of 119 patients (12.6%, exact confidence interval 7.2-19.9). None of the 45 patients who received octreotide intraoperatively experienced intraoperative complications compared with eight of the 73 patients (11.0%) who did not receive octreotide (P=0.023). The presence of carcinoid heart disease and high urinary output of 5-hydroxyindoleacetic acid preoperatively were statistically significant risk factors for perioperative complications.

Perianesthetic risks and outcomes of pheochromocytoma and paraganglioma resection.

UNLABELLED: Pheochromocytomas and paragangliomas are often surgically curable. However, resection of these tumors can be life threatening. We undertook this study to determine the frequency of, and risk factors for, perioperative complications in patients undergoing resection of pheochromocytoma or paraganglioma. We retrospectively reviewed the medical records of patients during 1983-1996 who underwent surgical resection of catecholamine-secreting pheochromocytoma or paraganglioma. Preoperative risk factors, adverse intraoperative events, and complications occurring in the 30 days after operation were recorded. Blood pressures were collected from manual records. The ranked sum test and Fisher's exact test were used for analyses. Adverse perioperative events or complications occurred in 45 of 143 patients (31.5%; exact 95% confidence interval, 24.0% to 39.8%). Of these 45 patients, 41 experienced one or more adverse intraoperative events. The most common adverse event was sustained hypertension (36 patients). There were no perioperative deaths, myocardial infarctions, or cerebrovascular events. Preoperative factors univariately associated with adverse perioperative events included larger tumor size (P: = 0.007), prolonged duration of anesthesia (P: = 0.015), and increased levels of preoperative urinary catecholamines and catecholamine metabolites: vanillylmandelic acid (P: = 0.019), metanephrines (P: = 0.004), norepinephrine (P: = 0. 014), and epinephrine (P: = 0.004). Despite premedication of most patients with phenoxybenzamine and a beta-adrenergic blocker, varying degrees of intraoperative hemodynamic lability occurred. IMPLICATIONS: Few patients who had pheochromocytoma or paraganglioma resection experienced significant perioperative morbidity and none died in the largest retrospective study on this topic to date. This study confirms the very good perioperative outcomes demonstrated in smaller studies on this high-risk population, and identifies several risk factors for adverse outcomes.

Damage to photosystem II in symbiotic dinoflagellates: a determinant of coral bleaching.

Coral bleaching has been defined as a general phenomenon, whereby reef corals turn visibly pale because of the loss of their symbiotic dinoflagellates and/or algal pigments during periods of exposure to elevated seawater temperatures. During the summer of 1997, seawater temperatures in the Florida Keys remained at or above 30 degrees C for more than 6 weeks, and extensive coral bleaching was observed. Bleached colonies of the dominant Caribbean reef-building species, Montastrea faveolata and Montastrea franksi, were sampled over a depth gradient from 1 to 17 m during this period of elevated temperature and contained lower densities of symbiotic dinoflagellates in deeper corals than seen in previous "nonbleaching" years. Fluorescence analysis by pulse-amplitude modulation fluorometry revealed severe damage to photosystem II (PSII) in remaining symbionts within the corals, with greater damage indicated at deeper depths. Dinoflagellates with the greatest loss in PSII activity also showed a significant decline in the D1 reaction center protein of PSII, as measured by immunoblot analysis. Laboratory experiments on the temperature-sensitive species Montastrea annularis, as well as temperature-sensitive and temperature-tolerant cultured symbiotic dinoflagellates, confirmed the temperature-dependent loss of PSII activity and concomitant decrease in D1 reaction center protein seen in symbionts collected from corals naturally bleached on the reef. In addition, variation in PSII repair was detected, indicating that perturbation of PSII protein turnover rates during photoinhibition at elevated temperatures underlies the physiological collapse of symbionts in corals susceptible to heat-induced bleaching.

Perianesthetic dental injuries: frequency, outcomes, and risk factors.

BACKGROUND: Dental injury is well-recognized as a potential complication of laryngoscopy and tracheal intubation. However, the frequency, outcomes, and risk factors for this problem have not been documented in a well-defined patient population. METHODS: The authors analyzed the dental injuries of 598,904 consecutive cases performed on patients who required anesthetic services from 1987 through 1997. Dental injuries were defined as perianesthetic events (those occurring within 7 days) that required dental interventions to repair, stabilize, or extract involved dentition or support structures. A 1:3 case-control study of 16 patient and procedural characteristics was performed for cases that occurred during the first 5 yr of the study. Conditional logistic regression was used for data analysis. RESULTS: There were 132 cases (1:4,537 patients) of dental injury. One half of these injuries occurred during laryngoscopy and tracheal intubation. The upper incisors were the most commonly involved teeth, and most injuries were crown fractures and partial dislocations and dislodgements. Multivariate risk factors for dental injury in the case control study included general anesthesia with tracheal intubation (odds ratio [OR] = 89), preexisting poor dentition (OR = 50), and increased difficulty of laryngoscopy and intubation (OR = 11). CONCLUSIONS: Based on these data from a large surgical population at a single training institution, approximately 1:4,500 patients who receive anesthesia services sustain a dental injury that requires repair or extraction. Patients most at risk for perianesthetic dental injury include those with preexisting poor dentition who have one or more risk factors for difficult laryngoscopy and tracheal intubation.

Perioperative pulmonary aspiration in infants and children.

BACKGROUND: Pulmonary aspiration of gastric contents during the perioperative period in infants and children may be associated with postoperative mortality or pulmonary morbidity. There has not been a recent determination of the frequency of this event and its outcomes in infants and children. METHODS: The authors prospectively identified all cases of pulmonary aspiration of gastric contents during the perioperative courses of 56,138 consecutive patients younger than 18 yr of age who underwent 63,180 general anesthetics for procedures performed in all surgical specialties from July 1985 through June 1997 at the Mayo Clinic. RESULTS: Pulmonary aspiration occurred in 24 patients (1: 2,632 anesthetics; 0.04%). Children undergoing emergency procedures had a greater frequency of pulmonary aspiration compared to those undergoing elective procedures (1:373 vs. 1:4,544, P < 0.001). Fifteen of the 24 children who aspirated gastric contents did not develop respiratory symptoms within 2 h of aspiration, and none of these 15 developed pulmonary sequelae. Five of these nine children who aspirated and in whom respiratory symptoms developed within 2 h subsequently had pulmonary complications treated with respiratory support (P < 0.003). Three children were treated with mechanical ventilation for more than 48 h, but no child died of sequelae of pulmonary aspiration. CONCLUSIONS: In this study population, the frequency of perioperative pulmonary aspiration in children was quite low. Serious respiratory morbidity was rare, and there were no associated deaths. Infants and children with clinically apparent pulmonary aspiration in whom symptoms did not develop within 2 h did not have respiratory sequelae.

Diabetes mellitus and difficult laryngoscopy in renal and pancreatic transplant patients.

UNLABELLED: Limited mobility of the cervical spine or temperomandibular joint may contribute to increased difficulty of laryngoscopy in patients who have severe diabetes mellitus. The frequency of difficult laryngoscopy in diabetics undergoing renal and/or pancreatic transplants has been reported to be as high as 32%. We retrospectively reviewed the anesthetic records of all adult patients who underwent renal and/or pancreatic transplant and endotracheal intubation from January 1, 1985 to October 31, 1995. Characteristics specifically reviewed included the presence of diabetes mellitus, type of organ donor, age, gender, body mass index, previous difficult laryngoscopy, known characteristics potentially related to difficult laryngoscopy, and degree of difficulty with laryngoscopy. Laryngoscopy was graded as easy, minimally to moderately difficult, and moderately to extremely difficult to perform. Factors associated with any degree of difficult intubation were univariately assessed by using Fisher's exact test. Of 725 patients, 15 (2.1%) were identified as having difficult laryngoscopies, although all underwent successful endotracheal intubations. Factors associated with difficult laryngoscopy were diabetes mellitus (P = 0.002) and characteristics known to be related to difficult laryngoscopy (P = 0.02). These findings confirm an increase in the frequency of difficult laryngoscopy in diabetic patients undergoing renal and/or pancreatic transplant, although no laryngoscopies were rated as moderately to extremely difficult. We conclude that the frequency of difficult laryngoscopy in these diabetic patients is much lower than previous reports have suggested. IMPLICATIONS: Previous studies have suggested that airway management of many diabetic patients may be difficult. Our medical record review of patients with severe diabetes undergoing organ transplants showed that extraordinary techniques were not required to successfully manage their airways.

Risks and outcomes of perioperative pulmonary aspiration.

A 95 kg, 34-year-old woman undergoes a laparoscopic tubal ligation. Shortly after endotracheal extubation and during transport to the PACU, she attempts to cough, and gags and vomits. As she is wheeled into the PACU, she is coughing and cyanotic. The anesthesiologist quickly reanesthetizes and reintubates her. Concerned that she may have aspirated the vomitus into her trachea, you suction her endotracheal tube and find thick bilious secretions. How important is pulmonary aspiration? What are the risk factors? When does aspiration occur during the perioperative period? How do you treat pulmonary aspiration? What went wrong here?

Outcomes of patients with no laboratory assessment before anesthesia and a surgical procedure.

OBJECTIVE: To estimate the frequency of perioperative morbidities in patients who underwent anesthesia and a surgical procedure with no preoperative laboratory testing. MATERIAL AND METHODS: We conducted an electronic database search of medical records of 56,119 patients who underwent surgical or diagnostic procedures and anesthesia at Mayo Clinic Rochester in 1994 and found 5,120 who had no laboratory tests done within 90 days before the procedure. From this group, we randomly selected 1,044 patients (87 from each month) to document the absence of preoperative tests, the presence of preexisting disease (by organ system), the type of anesthetic agent, and the outcomes and tests intraoperatively and postoperatively. RESULTS: The 1,044 patients ranged in age from 0 to 95 years (median age, 21). No deaths or major perioperative morbidities occurred (0.0%; exact 95% confidence interval, 0.00 to 0.35%). Although 10 patients underwent blood typing and screening for antibodies immediately preoperatively, no blood transfusions were necessary. Intraoperatively, 17 laboratory tests and 1 electrocardiogram were obtained, and 3 results were abnormal. Postoperatively, 42 blood tests and 2 electrocardiographic procedures were performed. Five of the 42 blood tests showed abnormal results (hemoglobin levels in 3, serum sodium in 1, and arterial blood gases in 1). One electrocardiogram showed normal findings, and the other revealed normal results except for premature ventricular contractions. No laboratory test done intraoperatively or postoperatively was found to change surgical or medical management substantially. One patient who had unanticipated blood loss during an outpatient procedure was admitted to the hospital for observation. CONCLUSION: All 1,044 patients, 97% of whom were relatively healthy, with no recent laboratory testing safely underwent anesthesia and an operation. We conclude that patients who have been assessed by history and physical examination and determined to have no preoperative indication for laboratory tests can safely undergo anesthesia and operation with tests obtained only as indicated intraoperatively and post-operatively. Current anesthetic and medical practices rapidly identify perioperative indications for laboratory evaluation as they arise.

Effect of intraoperative anesthetic events on postoperative patient satisfaction.

OBJECTIVE: To assess overall perioperative and anesthetic care-specific patient satisfaction. DESIGN: We mailed questionnaires postoperatively to three groups of surgical patients (those who underwent anesthesia without complications, those who experienced airway management difficulties, and those who had cardiovascular perturbations) and analyzed the responses. MATERIAL AND METHODS: All patients 18 to 75 years of age who underwent hospital-based surgical procedures in our acute-care hospitals during the interval from January to September 1993 were eligible for this investigation. We asked a total of 315 patients--105 in each of the three study groups--about their satisfaction with perioperative care. Specific positive or negative comments that the patients returned in their questionnaires were tabulated into the following sub-categories: physician, nurse, technique, time, and institution concerns. RESULTS: Of the 315 questionnaires sent to patients, 239 (75.9%) were returned. No difference in overall patient satisfaction (defined as very satisfied or a combination of very satisfied and satisfied) was noted among the groups. No patients identified themselves as dissatisfied or very dissatisfied with their overall care, although a small percentage expressed dissatisfaction because of time delays. The specific patient comments suggested that the positive interactions with physicians and nurses outweighed the concerns about time delays. CONCLUSION: This study showed that intraoperative anesthetic events did not affect patient satisfaction. Interactions with physicians and nurses dominated the decision about patient satisfaction, and time delays were the most frequently cited negative comment.

Bleaching Patterns of Four Species of Caribbean Reef Corals.

Bleaching of reef corals, involving loss of symbiotic algae (= zooxanthellae), loss of algal pigments, or both, has been linked to temperature stress. In this study the effects of high temperature and light on zooxanthellae living in the Caribbean reef corals Montastrea annularis, M. cavernosa, Agaricia agaricites, and A. lamarcki were studied. Pieces of coral colonies were incubated at ambient seawater temperature (26{deg} +/- 1{deg}C), and at 30{deg}, 32{deg}, and 34{deg}C. Symbiotic algae from M. annularis, a species of coral from the forereef that commonly bleaches, showed the following sequence of events when exposed to natural light at 32{deg}C; loss of photosynthetic potential measured as fluorescence yield, corresponding reduction of both oxygen production per zooxanthella and P:R (photosynthesis:respiration) ratio, and subsequent reduction in density of algae in relation to surface area of the coral. These parameters were not significantly reduced and no deaths occurred for M. annularis or any other coral species maintained at 26{deg} or 30{deg}C. However, the sequence of events was condensed to less than 24 h when M. annularis was subjected to 34{deg}C seawater, except that there was little if any reduction in algal density before tissue-sloughing and death occurred between 10 and 24 h. Loss of significant amounts of chlorophyll a per alga was not evident for any corals except those maintained at 34{deg}C longer than 10 h. In contrast, symbiotic algae in M. cavernosa, a species that rarely bleaches in nature, showed only slight reductions in photosynthesis and fluorescence yield, and no significant loss of algal cells or chlorophyll a, when maintained in seawater at 32{deg}C for 2 days. Thus zooxanthellae in M. cavernosa appeared to be less affected by sublethal high-temperature stress. Similar contrasting patterns of bleaching were seen in zooxanthellae from the plating coral Agaricia lamarcki, which often bleaches during the late summer and fall, compared with zooxanthellae from A. agaricites, a coral which bleaches less frequently. In addition, M. annularis exposed to sublethal high temperatures and ambient light bleached faster than those kept in dimmer light, supporting past field observations suggesting that light energy is an important component of bleaching in nature. When M. annularis was exposed to different wavelengths of natural light at 32{deg}C, the fluorescence yield declined more quickly in the presence of higher energy UV-A and blue light than with other photosynthetically active radiation. Natural levels of UV-B had little effect in this study. These data suggest that the patterns of bleaching seen in nature may be at least partially explained by different tolerances of the symbiotic algae in the corals, and that light plays a significant role in bleaching.

Ulnar neuropathy. Incidence, outcome, and risk factors in sedated or anesthetized patients.

BACKGROUND: Ulnar neuropathy is well-recognized as a potential complication of procedures performed on anesthetized patients. However, reported outcomes and risk factors for this problem are based on small series and anecdotes. METHODS: We retrospectively reviewed the perioperative courses of 1,129,692 consecutive patients who underwent diagnostic and noncardiac surgical procedures with concurrent anesthetic management at the Mayo Clinic from 1957 through 1991 (inclusive). The medical diagnoses of patients who had these procedures were scanned for 26 diagnoses associated with neuropathy. Persistent neuropathy of an ulnar nerve was defined as a sensory or motor deficit of greater than 3 months' duration. Risk factors anecdotally associated with persistent neuropathy were analyzed by comparing patients with an ulnar neuropathy with control subjects in a 1:3 case-control study. RESULTS: Persistent ulnar neuropathies were identified in 414 patients, a rate of 1 per 2,729 patients. Of these, 38 (9%) patients had bilateral neuropathies. Approximately equal numbers of the neuropathies included sensory loss only or mixed sensory and motor loss. Initial symptoms form most neuropathies were noted more than 24 h after the procedure. Factors associated with persistent ulnar neuropathy included male gender and a duration of hospitalization of more than 14 days (P < 0.01). Neuropathy was more likely to develop in very thin and obese patients than in patients with average body habitus. Neither the type of anesthetic technique nor the patient position was found to be associated with this neuropathy. Of the 382 patients who survived the 1st postoperative yr, 53% regained complete motor function and sensation and were asymptomatic. Of those with neuropathies persisting for more than 1 yr, most had moderate or greater disability from pain or weakness. CONCLUSIONS: These data suggest that perioperative ulnar neuropathies are associated with factors other than general anesthesia and intraoperative positioning. Men at the extremes of body habitus who have prolonged hospitalizations are particularly susceptible to development of ulnar neuropathies.

Clinical significance of pulmonary aspiration during the perioperative period.

BACKGROUND: Pulmonary aspiration of gastric contents during the perioperative period may be associated with postoperative mortality or pulmonary morbidity. Recent determination of the incidence of perioperative pulmonary aspiration and evaluation of factors related to clinical outcomes is lacking. METHODS: We retrospectively reviewed the perioperative courses of 172,334 consecutive patients 18 yr of age or older who underwent 215,488 general anesthetics for procedures performed in all surgical specialties from July 1985 to June 1991. Pulmonary aspiration was defined as either the presence of bilious secretions or particulate matter in the tracheobronchial tree or, in patients who did not have their tracheobronchial airways directly examined after regurgitation, the presence of an infiltrate on postoperative chest roentgenogram that was not identified by preoperative roentgenogram or physical examination. RESULTS: Pulmonary aspiration occurred in 67 patients (1:3,216 anesthetics). Fifteen aspirations occurred in 13,427 (1:895) anesthetics of patients undergoing emergency surgery, and 52 occurred in 202,061 (1:3,886) anesthetics of patients undergoing elective surgery (P < .001). Of the 66 patients who survived their surgery, 42 (64%) did not develop a cough or wheeze, a decrease in arterial hemoglobin oxygen saturation while breathing room air > 10% less than the preoperative value, or radiographic abnormalities within 2 h of aspiration. These 42 patients had no respiratory sequelae. Of the 24 patients who had one or more of these findings, 13 required mechanical ventilatory support for more than 6 h. Three of the six patients whose lungs required mechanical ventilation for more than 24 h died from pulmonary insufficiency (overall mortality = 1:71,829 anesthetics). CONCLUSIONS: This study suggests that patients with clinically apparent aspiration who do not develop symptoms within 2 h are unlikely to have respiratory sequelae.

Role of preoperative cessation of smoking and other factors in postoperative pulmonary complications: a blinded prospective study of coronary artery bypass patients.

The association between preoperative smoking cessation and postoperative pulmonary morbidity was studied prospectively in 200 consecutive patients undergoing an elective coronary artery bypass surgical procedure. Detailed respiratory, cardiovascular, and smoking histories were elicited. Preoperative arterial blood gas analyses and bedside spirometry were performed. Urinary cotinine levels were measured to verify smoking histories. During spirometry, severe angina developed in seven patients, who were hence excluded from the study; one patient died of hemorrhage intraoperatively. An observer unaware of patients' preoperative histories assessed the remaining 192 patients throughout the intraoperative and postoperative periods for pulmonary complications. Postoperative pulmonary complications occurred in a third of the current smokers. Patients who had stopped smoking for 2 months or less had a pulmonary complication rate almost 4 times that of patients who had stopped for more than 2 months (57.1% versus 14.5%). Patients who had stopped smoking for more than 6 months had rates similar to those who had never smoked (11.1% and 11.9%, respectively). Preoperative pulmonary dysfunction, increased pack-years of smoking, prolonged surgical time, and the use of enflurane were independently associated with postoperative pulmonary morbidity (P less than 0.05). We concluded that smoking cessation should occur at least 2 months preoperatively to maximize the reduction of postoperative respiratory complications.

Clinical efficacy of high frequency jet ventilation during extracorporeal shock wave lithotripsy of renal and ureteral calculi: a comparison with conventional mechanical ventilation.

The use of high frequency jet ventilation compared to conventional mechanical ventilation during general anesthesia for extracorporeal shock wave lithotripsy of renal or ureteral calculi can reduce stone movement. This decrease in stone movement theoretically lessens the total shock and energy requirements for stone fragmentation and perirenal tissue damage. To assess these theoretical advantages of high frequency jet ventilation, we studied patients undergoing extracorporeal shock wave lithotripsy to determine differences in stone movement during high frequency jet and conventional mechanical ventilation (30 patients), and in total shock requirements (1,174 patients). Mean stone movement in the 30 patients was 34.3 +/- 4.3 mm. during conventional mechanical ventilation compared to 4.1 +/- 1.9 mm. during high frequency jet ventilation (p less than 0.001). Mean total shocks were 1,542 +/- 212 (452 patients) during conventional mechanical ventilation compared to 1,217 +/- 165 (722 patients) during high frequency jet ventilation (p less than 0.001). Only 1 patient in the study had clinically significant perirenal tissue damage. We conclude that high frequency jet ventilation when compared to conventional mechanical ventilation results in clinically and economically beneficial decreases in total shocks for extracorporeal shock wave lithotripsy fragmentation of renal or ureteral calculi.