Biomedical subjects

Michael J Tessler

Publications and source records attributed to Michael J Tessler.

5 recordsLinked to original sources

PubMed2006

Audio spectrum and sound pressure levels vary between pulse oximeters.

PURPOSE: The variable-pitch pulse oximeter is an important intraoperative patient monitor. Our ability to hear its auditory signal depends on its acoustical properties and our hearing. This study quantitatively describes the audio spectrum and sound pressure levels of the monitoring tones produced by five variable-pitch pulse oximeters. METHODS: We compared the Datex-Ohmeda Capnomac Ultima, Hewlett-Packard M1166A, Datex-Engstrom AS/3, Ohmeda Biox 3700, and Datex-Ohmeda 3800 oximeters. Three machines of each of the five models were assessed for sound pressure levels (using a precision sound level meter) and audio spectrum (using a hanning windowed fast Fourier trans-form of three beats at saturations of 99%, 90%, and 85%). RESULTS: The widest range of sound pressure levels was produced by the Hewlett-Packard M1166A (46.5 +/- 1.74 dB to 76.9 +/- 2.77 dB). The loudest model was the Datex-Engstrom AS/3 (89.2 +/- 5.36 dB). Three oximeters, when set to the lower ranges of their volume settings, were indistinguishable from background operating room noise. Each model produced sounds with different audio spectra. Although each model produced a fundamental tone with multiple harmonic overtones, the number of harmonics varied with each model; from three harmonic tones on the Hewlett-Packard M1166A, to 12 on the Ohmeda Biox 3700. There were variations between models, and individual machines of the same model with respect to the fundamental tone associated with a given saturation. CONCLUSION: There is considerable variance in the sound pressure and audio spectrum of commercially-available pulse oximeters. Further studies are warranted in order to establish standards.

Equipment Design↗

PubMed2006

Documentation on the anesthetic record: Correlation with clinically important variables.

PURPOSE: A survey was undertaken at a single Academic Health Sciences Centre to document the opinions of anesthesiologists regarding what variables are important to document on the anesthetic record. A subsequent chart review of anesthetic records was undertaken to determine the extent to which these anesthesiologists record the variables they consider important. METHODS: A survey form was mailed to all practicing staff anesthesiologists at the four adult McGill University affiliated hospitals. Anesthesiologists were asked to rank 23 preoperative and 33 intraoperative variables on a scale from 1-5: (1 = essential; 2 = important; 3 = useful; 4 = not important; 5 = excessive information). All variables considered by consensus < or = 2 (important to essential) were then assessed as to whether they were recorded on 60 charts randomly selected from each of the four teaching hospitals. Only anesthetic records completed by staff anesthesiologists were evaluated. RESULTS: Ninety percent (47/52) of survey forms were completed and returned. Preoperative variables considered most important to document included examination of the patient's airway and allergy status. Intraoperative variables considered most important for documentation were the patient's vital signs. The only variable to have been recorded on all the anesthetic records was the anesthesiologist's name. The allergy status was the most recorded preoperative variable (84% of charts). The recording rates of intraoperative variables ranged from 100% (anesthesiologist's name, start time of anesthesia) to 24% (estimated blood loss). CONCLUSION: McGill anesthesiologists consider many preoperative and intraoperative variables to be important to document on the anesthetic record. However, subsequent chart review indicated that many of these variables are recorded inconsistently. The transmission of anesthesia-related medical information might be improved if anesthesiologists recorded more consistently information they consider to be important.

Adult↗

PubMed2004

Desflurane does not accelerate recovery from operations of short duration: a practice audit.

PURPOSE: Desflurane, a newer inhalation anesthetic agent, has been promoted as a superior drug because patients will awaken sooner after anesthesia. This has only been proven in operations of long duration (i.e., more than one hour). We assessed our experience using desflurane in short out-patient surgery with a retrospective analysis of a single surgeon's elective laparoscopic cholecystectomy patients. METHODS: With Institutional consent, we performed a retrospective comparison of the postoperative recovery of patients who received desflurane/air/oxygen to historical control patients who received isoflurane/N2O/oxygen. RESULTS: Patient preoperative characteristics were similar in the two groups. Duration of surgery and the time from the end of surgery to patient leaving the operating room for the desflurane and isoflurane/N2O groups were (in minutes) 42.7 +/- 13.5 and 9.6 +/- 4.6 vs 47.2 +/- 15.1 and 8.5 +/- 4.1 respectively (P = NS). Total Aldrete scores upon presentation to the postanesthesia care unit (PACU) were 8.1 +/- 1.4 and 7.9 +/- 1.8 for the two groups respectively (P = NS). The percentage of patients who arrived in the PACU with consciousness scores of 2, 1, 0 for the desflurane and isoflurane/N2O groups were 20.4, 75.5, and 4.1 vs 14.6, 73.2 and 12.2 respectively (P = NS). Mean length of stay in the PACU for the two groups was 160 +/- 111 and 156 +/- 114 min (P = NS). CONCLUSION: Our results show that in short procedures the use of desflurane does not necessarily result in faster patient recovery or discharge from the PACU.

Adult↗

PubMed2002

Acute vision impairment: does it affect an anesthesiologist's ability to intubate the trachea?

UNLABELLED: The result of impaired vision on an anesthesiologist's ability to intubate the trachea is unknown. We studied 12 attending staff anesthesiologists as they intubated 2 anesthesia mannequins (A and B) under 6 conditions. The conditions were: 1) usual vision, 2) central-vision loss with 20/500 bilaterally and a 24 degrees central scotoma, 3) peripheral-field loss with 20/20 bilaterally and a 7 degrees visual field, 4) peripheral-field loss with 20/20 bilaterally and a 3.5 degrees visual field, 5) central-vision loss with 20/200 bilaterally and a 12 degrees central scotoma, and 6) right eye ocular media opacity and 20/70 left eye usual acuity. The time to intubation was recorded by stopwatch from gripping the laryngoscope until the anesthesiologist signaled that the endotracheal tube was properly placed in the trachea. The mean +/- SD times to intubation for Mannequins A and B were 16.0 +/- 3.3, 31.9 +/- 10.4, 26.4 +/- 9.0, 26.4 +/- 7.7, 22.4 +/- 5.1, 25.5 +/- 16.9 and 16.6 +/- 6.6, 26.9 +/- 10.0, 21.4 +/- 9.2, 21.4 +/- 5.8, 21.5 +/- 7.7, 17.7 +/- 5.1 s for the 6 conditions, respectively. Multiple analysis of variance revealed a highly significant difference for the time to successful intubation between the anesthesiologists' usual vision and the vision-impaired conditions. There was a significant improvement in time to successful intubation from the first to subsequent intubation attempts. There were also more esophageal intubations in the vision-impaired conditions. This implies that anesthesiologists who develop acute severe vision impairment might have more difficulty intubating the trachea, which could initiate more critical incidents. The results of this study cannot be applied to anesthesiologists with chronic vision impairment. IMPLICATIONS: We found that acute severe vision impairment adversely affects the anesthesiologist's ability to intubate the trachea. This implies that anesthesiologists with acute onset of severe visual handicaps might have more difficulty intubating the trachea, which could initiate more critical incidents.

Acute Disease↗

PubMedDate not supplied

Ketorolac analgesia for inguinal hernia repair is not improved by peripheral administration.

PURPOSE: It has been suggested that ketorolac, a non-steroidal anti-inflammatory drug (NSAID) available for parenteral use, may result in prolonged (24 hr) postoperative analgesia through a peripheral mechanism when added to local anesthetic infiltration. Our objective was to assess this effect by controlling for systemic absorption of the drug. METHODS: This randomized, double-blind trial studied 40 men undergoing elective inguinal hernia repair under spinal anesthesia. All patients received 19 mL of lidocaine 1% infiltrated in the operative field before incision. Patients were randomized into two groups of 20. The surgical site group received ketorolac 30 mg added to the lidocaine infiltration. In the control group, ketorolac 30 mg was injected subcutaneously in the contralateral abdominal wall. Numeric rating scores (0-10) of pain at rest and with movement were recorded at the time of discharge from the recovery room and at 24 hr postoperatively. Time to first analgesia, postoperative iv morphine use, total time in the recovery room, and total oral analgesic use in the first 24 hr were also compared. RESULTS: There were no significant differences between groups with respect to any of the measured variables. In both groups, pain scores were low at rest (1.9 +/- 1.4 vs 2.2 +/- 1.8, surgical site and systemic groups, respectively) and moderate with movement (5.3 +/- 2.2, 5.0 +/- 1.8) after anesthetic recovery. Pain scores were similar at 24 hr (1.1 +/- 1.3, 1.9 +/- 1.6 at rest; 5.7 +/- 2.0, 6.2 +/- 2.2 with movement). CONCLUSION: Adding ketorolac to lidocaine infiltration for hernia repair does not improve or prolong postoperative analgesia compared to systemic administration.

Adult↗