Donald D. Mathes

Dilutional acidosis: is it a real clinical entity?

Dilutional acidosis occurs as a result of rapid extracellular volume expansion decreasing the measured serum bicarbonate. This phenomenon is not well described in the literature. Searching the English medical literature, we found only one case report of dilutional acidosis 1 and no case reports of dilutional acidosis occurring within the perioperative period. Several authors have concluded that dilutional acidosis has little actual clinical significance because of cellular buffering in which rapid extracellular volume expansion caused only minimal changes in measured extracellular bicarbonate and pH levels. 2-4 We report a case of dilutional acidosis occuring intraoperatively as a direct result of giving a large volume of isotonic saline.

The importance of the postoperative anesthetic visit : Do repeated visits improve patient satisfaction or physician recognition ?

This study evaluates whether repeated postoperative visits by the anesthesiologist improve patient ability to recall the anesthesiologists name and the patients perception of and satisfaction with anesthesia services.In a randomized, prospective trial, 144 patients with an anticipated postoperative length of stay of at least three days were enrolled in three groups: Group A patients (n = 48) had one postoperative visit, Group B (n = 48) had two postoperative visits, and Group C (n = 48) had three postoperative visits. All postoperative visits were performed by the attending anesthesiologist on consecutive postoperative days. Patients were contacted two days after their last postoperative visit to complete a study questionnaire. Patients were able to recall the anesthesiologists name significantly less frequently than the surgeons name, and there was no difference in name recall among groups. Recall was not affected by patient age, sex, or ASA physical status; the mode of contact (telephone versus personal visit); the anesthesiologists gender; the presence of preoperative medication; or the identity of the preoperative evaluator. Patients could identify the anesthesiologists gender approximately 85% of the time, regardless of group, and were more likely to identify female anesthesiologists (P = 0.026, odds ratio 3.3). Patient evaluation of hospital, surgical, and anesthesia care was favorable in all groups and did not vary with group. Increasing the number of postoperative visits does not improve patient name recognition of the anesthesiologist or increase patient satisfaction with or perception of anesthesia services. (Anesth Analg 1996;83:793-7)

Rhabdomyolysis and Myonecrosis in a Patient in the Lateral Decubitus Position

RHABDOMYOLYSIS, from muscle necrosis, is known to occur in certain surgical positions, most notably the dorsal lithotomy and knee chest. This complication is often attributed to compromise of venous and arterial blood flow. Several cases of rhabdomyolysis and gluteal myonecrosis have been reported to occur in patients in the lateral decubitus position undergoing hip surgery. These complications have been attributed to the posterior clamp pressing directly on the buttocks instead of the sacrum area and to the anterior public clamp being placed against the anterior part of the dependent thigh, causing vascular compromise at the groin. 1,2 We report a case of rhabdomyolysis occurring solely from the direct and prolonged pressure of the operating room bed against the gluteal and flank muscles in a patient in the lateral decubitus position.

Video as a Patient Teaching Tool: Does It Add to the Preoperative Anesthetic Visit?

M eeting the anesthesiologist is one of the surgical patient’s highest priorities preoperatively (l), and several reports document that this interaction reduces patient anxiety (2-4). High anxiety may be associated with poorer surgical outcome (5), whereas improved patient education is associated with increased patient satisfaction (6) and improved clinical outcome (7). Video instruction may supplement conventional instruction techniques for general medical patients (8) and aid in obtaining informed consent (9). No study has specifically evaluated an instructional video about anesthesia as a tool for educating surgical patients about their upcoming anesthetic and facilitating the anesthesiologist-patient relationship. The hypothesis of this study is that viewing an anesthesia preoperative video will improve patient knowledge and patient perception of the upcoming anesthetic and surgery compared to a standard preoperative interview without video instruction.

Bleomycin and hyperoxia exposure in the operating room.

I s hyperoxia exposure (FIo, 2 30%) in a patient previously treated with bleomycin (BLM) safe? This question is controversial and has elicited many conflicting case reports and studies. This paper examines the following: 1) the history of BLM use; 2) the mechanism of damage and pharmacokinetics of BLM; 3) the risk factors predisposing the patients to pulmonary toxicity from BLM; 4) conflicting case studies of BLM-treated patients and hyperoxia exposure; 5) animal studies on BLM hyperoxia exposure which help explain the conflicting human data; and 6) a new chemotherapy drug which may replace BLM.

Ambulatory surgery: room air versus nasal cannula oxygen during transport after general anesthesia.

We compared outpatients transported to the postanesthesia care unit (PACU) while breathing room air to 2–4 L/min nasal cannula oxygen (O2) to test the hypothesis that routine supplemental O2 during transport is not required after general anesthesia in an ambulatory surgery center. We also examined whether the arbitrary arrival PACU O2 saturations of >92% may be used to predict an infrequent incidence of subsequent significant desaturations (<90%) in the PACU. One-hundred-ninety patients were randomized to receive either room air or 2–4 L/min nasal cannula for transport to PACU after receiving general anesthesia. O2 saturations were recorded before surgery, just before leaving the operating room, and upon arrival in the PACU. The lowest O2 saturation occurring in the PACU was also recorded. The mean arrival PACU O2 saturation was 95.0 in the Room Air group, compared with 97.2 for the Nasal Cannula (NC) group, a statistically significant difference (P < 0.001). In the Room Air group, 20% had arrival O2 saturations ≤92%, and half of these (10%) had O2 saturations <90%. In the NC group, 6% had O2 saturations ≤92%, of which one third (2%) were <90% on arrival in the PACU. All of these initial desaturations were easily corrected with face-tent O2 administration, deep breathing, or both. Subgroup analysis revealed that patients whose ages were 60 yr or older or those weighing 100 kg or more had lower arrival room air saturations than their younger or slimmer counterparts. In the Room Air group, only three (3.9%) of the patients that arrived in PACU with O2 saturations >92% had subsequent desaturations <90%, compared with seven (7.9%) in the NC group. We conclude that most adult patients undergoing ambulatory surgery can be transported safely to the PACU breathing room air after general anesthesia. However, patients whose age was ≥60 yr or weight was ≥100 kg, or for whom transient O2 desaturation on transport may be harmful, should be transported while breathing nasal O2 via nasal cannula.

Iatrogenic superior gluteal mononeuropathy

Injuries to the superior gluteal nerve (SGN) have been reported as a result of trauma, pyriformis muscle entrapment, injections, and lumbar lordosis and inadequate back stabilization. We report 3 patients who developed isolated SGN injuries, 1 after a partial nephrectomy and 2 following revision of a total hip arthroplasty. SGN should be suspected in anyone developing an abnormal gait after hip or pelvic surgery or after prolonged lateral decubitus positioning.