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Biomedical subjects

R David Warters

Publications and source records attributed to R David Warters.

8 recordsLinked to original sources
PubMed2003

Increased body mass index per se is not a predictor of difficult laryngoscopy.

PURPOSE: We investigated the association between morbid obesity and difficult laryngoscopy (DL). METHODS: In a prospective, controlled study we evaluated the impact of different variables on the prediction of DL in 200 morbidly obese (study group-SG), and 1272 non-obese (control group-CG) patients undergoing elective surgery. Variables assessed included age, sex, body mass index (BMI), protruding, loose, and missing upper teeth, thyro-mental distance, temporo-mandibular joint (TMJ) function, neck extension, and Mallampati class. A Cormack grade III or IV was considered DL. RESULTS: The SG patients were younger (P < 0.000), there were more females in the SG (P < 0.000) and more in the SG had teeth problems (P = 0.026). More patients in the SG (10% vs 1%), had obstructive sleep apnea (P < 0.001) with 90% of them in the SG having a grade III laryngoscopy. High BMI did not affect the laryngoscopy difficulty (P = 0.56). Multivariable regression analysis revealed that morbid obesity, increased age, male sex, pathology of TMJ, and higher Mallampati class, were independent predictors of DL. When interaction between the predictors and the group was added to the multivariable model, the SG was no longer a predictor by itself, rather its association with abnormal upper teeth turned to be significant for prediction of DL. CONCLUSIONS: Increased age, male sex, TMJ pathology, Mallampati 3 and 4, a history of obstructive sleep apnea and abnormal upper teeth were associated with a higher incidence of DL. The magnitude of BMI had no influence on difficulty with laryngoscopy.

Adult↗
PubMed2003

Difficult airway management practice patterns among anesthesiologists practicing in the United States: have we made any progress?

STUDY OBJECTIVE: To determine the extent instruction and practice in the use of airway devices and techniques varies among anesthesiologists practicing in the United States. DESIGN: Survey questionnaire. SETTING: University medical center. MEASUREMENTS: Questionnaires were completed by American-trained anesthesiologists who attended the 1999 American Society of Anesthesiologists (ASA) Annual Meeting. Data collected included demographics, education, skills with airway devices/techniques, management of clinical difficult airway scenarios, and the use of the ASA Difficult Airway Algorithm. MAIN RESULTS: 1) DEMOGRAPHICS: 452 questionnaires were correctly completed; 62% attending anesthesiologists, 70% <50 years, 81% males, 44% from academic institutions, 63% >10 years of practice, 81% night duty, 77% board certified. 2) Education: 71% had at least one educational modality: difficult airway rotation, workshops, conferences, books, and simulators. 3) Skills: Miller blade 61%, Bullard laryngoscope 32%, LMA 86%, Combitube 43%, bougie 43%, exchangers 47%, cuffed oropharyngeal airway (COPA) 34%, retrograde 41%, transtracheal needle jet ventilation 34%, cricothyrotomy 21%, fiberoptics 59%, and blind nasal intubation 78%. The average reported use of special airway devices/techniques was 47.5%. 4) Management choices: failed intubation/ventilation: LMA (81%) and for all other situations: fiberoptic intubation. Use of ASA Difficult Airway Algorithm in clinical practice (86%). CONCLUSION: Fiberoptic intubation and the LMA are most popular in management of the difficult airway.

Anesthesia, Conduction↗
PubMed2002

The simultaneous measurement of ionized and total calcium and ionized and total magnesium in intensive care unit patients.

PURPOSE: This study was undertaken to determine the relationship between total magnesium and ionized magnesium in critically ill and injured patients. METHODS: Eighty consecutive intensive care unit (ICU) admissions were evaluated and 34 patients were enrolled in the study. Patients were enrolled who had indwelling arterial catheters and were within 4 days of ICU admission. Six milliliters of blood was collected and assayed simultaneously for total and ionized magnesium, total and ionized calcium, and albumin level. An Acute Physiology and Chronic Health Evaluation (APACHE II) score was calculated at the time of blood collection. RESULTS: The results of our study show a strong correlation between ionized and total magnesium (R =.903) that was not seen between ionized and total calcium (R =.748). We found total hypomagnesemia in 18% and ionized hypomagnesemia in 21% of ICU patients. We also found that 14.7% (5 of 34) of our patients had ionized hypermagnesemia whereas none displayed total hypermagnesemia. We did not find a correlation between APACHE II, sex, race, albumin level, and any electrolyte level. The mortality rate in the subjects studied was 21% (7 of 34). CONCLUSIONS: Based on our results we would recommend that intensivists directly measure ionized calcium whereas ionized magnesium can be inferred from total magnesium.

APACHE↗
PubMed2002

Endotracheal intubation with a gum-elastic bougie in unanticipated difficult direct laryngoscopy: comparison of a blind technique versus indirect laryngoscopy with a laryngeal mirror.

UNLABELLED: We evaluated the efficacy of intubation over a gum-elastic bougie by using either a blind technique or indirect laryngoscopy with a laryngeal mirror in patients with unexpected difficult direct laryngoscopy. In a prospective study, 60 consecutive patients with an unexpected Grade III or IV direct laryngoscopy were randomly allocated for intubation with a gum-elastic bougie either blindly (Group 1) or by indirect laryngoscopy with a laryngeal mirror (Group 2). We evaluated the failure rate of each method of intubation, complications related to either method, and the time required for intubation. Out of 725 patients evaluated over a 2-mo period, 60 patients (8.3%) had a Grade III laryngoscopy, and 30 of these were randomized into each group. There were 8 failed intubations in Group 1 compared with 1 failed intubation in Group 2 (P < 0.05). All eight failures in the blind intubation group ended with esophageal intubation. No additional complications were noted in either group. The time required for endotracheal intubation with each group was not significantly different (45 +/- 10 s versus 44 +/- 11 s). We conclude that intubation with a gum-elastic bougie had a lower failure rate using indirect laryngoscopy with a laryngeal mirror than a traditional blind technique. IMPLICATIONS: We evaluated the efficacy of intubation over a gum-elastic bougie by using either a blind technique or a laryngeal mirror. Intubation with a gum-elastic bougie had a lower failure rate using indirect laryngoscopy with a laryngeal mirror (P < 0.05) than a traditional blind technique.

Aged↗
PubMed2002

Impact of cardiopulmonary bypass management on postcardiac surgery renal function.

OBJECTIVE: Cardiac surgery on cardiopulmonary bypass (CPB) is associated with postoperative renal dysfunction and up to 4% of patients with normal preoperative renal function develop acute renal failure (ARF) requiring dialysis. According to recent investigations, CPB management is not evidence-based and, thus, current clinical CPB practice may favor renal dysfunction. The purpose of our study was to investigate if postcardiac surgery renal dysfunction is influenced by CPB management. METHODS: We selected three groups of patients with normal preoperative renal function who had been subjected to cardiac surgical procedures on CPB: 44 patients with postoperative ARF requiring hemofiltration/dialysis (ARF group), 51 patients with postoperative renal dysfunction not requiring hemofiltration/dialysis (serum creatinine increase > 0.5 mg/dl within 48 h postsurgery: CREA group), and 48 patients with normal postoperative renal function (Control group). The patients' on-line CPB records were analyzed for CPB duration, CPB perfusion pressure, CPB flow, and periods on CPB at a perfusion pressure <60 mmHg. On-CPB diuretic and vasoconstrictor medication was recorded. RESULTS: Patient demographics were similar for the three groups. In the ARF group, CPB duration was longer (166 +/- 77 [standard deviation, SD] min) compared to CREA (115 +/- 41 min; p < 0.001) and to Control groups (107 +/- 40 min; p < 0.001), and mean CPB flow was lower (2.35 +/- 0.36 l/min/m2) compared to CREA (2.61 +/- 0.35 l/min/m2; p = 0.0015) and to Control groups (2.51 +/- 0.33 l/min/m2; p = 0.09). Mean arterial pressure on CPB (ARF: 61 +/- 10; CREA: 60 +/- 7; CONTROL: 63 +/- 9 mmHg; p = 0.19) as well as furosemide and norepinephrine medication on CPB were similar for the groups. Compared to Control (46 +/- 26 min), CPB duration at arterial pressures <60 mmHg was longer in ARF (78 +/- 60 min; p = 0.034) and in CREA (62 +/- 36 min;p = 0.048). CONCLUSIONS: Our data suggest that current clinical CPB management impacts postoperative renal function. We found that patients with normal preoperative renal function who developed postoperative ARF had longer CPB duration, lower CPB perfusion flow, and longer periods on CPB at pressures < 60 mmHg compared to patients with no post CPB ARF. However, our data do not allow us to separate these CPB-related factors from the potential influence of perioperative low cardiac output syndrome as a cause for postoperative ARF. Thus, future clinical studies are required to elucidate CPB-induced ARF and to optimize CPB management for ARF prevention.

Acute Kidney Injury↗